Entire Vehicle (Commercial Vehicle Technology) 3662607654, 9783662607657

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Commercial Vehicle Technology

Michael Hilgers Wilfried Achenbach

Entire Vehicle

Commercial Vehicle Technology Series Editors Michael Hilgers, Weinstadt, Baden-Württemberg, Germany Wilfried Achenbach, HPCC2D-ENG, Daimler Trucks North America LLC, Portland, OR, USA

More information about this series at http://www.springer.com/series/16469

Michael Hilgers · Wilfried Achenbach

Entire Vehicle

Michael Hilgers Daimler Truck Stuttgart, Germany

Wilfried Achenbach Daimler Truck Portland, OR, USA

Commercial Vehicle Technology ISBN 978-3-662-60765-7 ISBN 978-3-662-60766-4  (eBook) https://doi.org/10.1007/978-3-662-60766-4 © Springer-Verlag GmbH Germany, part of Springer Nature 2021 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Planung/Lektorat: Markus Braun This Springer Vieweg imprint is published by the registered company Springer-Verlag GmbH, DE part of Springer Nature. The registered company address is: Heidelberger Platz 3, 14197 Berlin, Germany

Preface

For my children Paul, David and Julia, who share my passion for trucks, and for my wife Simone Hilgers-Bach who indulges us.

I have worked in the commercial vehicle industry for many years. I constantly hear comments which express essentially the same sentiment, “You develop trucks? That’s a young boy’s dream!” Indeed it is! Inspired by this enthusiasm, I have tried to learn as much as I possibly can about what goes into making commercial vehicles. In the process, I have discovered that one has not really grasped the subject matter until one can explain it cogently. Or to put it more clearly, “In order to really learn, you must teach.” Accordingly, as time went on I began to write down as many technical aspects of commercial vehicle technology as I could in my own words. I very quickly realized that the entire project needed to be organized logically, and once that was in place, the basic framework of this series of booklets on commercial vehicle technology practically compiled itself. This booklet in the series Commercial vehicle technology provides an introduction to the topic, and goes on to explain the commercial vehicle from the point of view of the user, that is to say the customer who uses the vehicle to earn a living. This is followed by a discussion of the fundamental qualities of the commercial vehicle as a whole. Other books in this series then deal with specific technical systems or properties of the vehicle. At this point, I would like to express my sincere thanks to my managers and many colleagues in the trucks division of Daimler AG for their support in the completion of this series. I would especially like to thank Dr. Lars Türk for his valuable suggestions and for proofreading the original German text. The most important new contributors to this text are my colleagues from Daimler Trucks North America, namely Derek Rotz and Dr. David Kayes who enriched and completed this text by adding information and figures on truck technology typical for the US. A very big thanky to their magnificent work! v

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Preface

My thanks go to the Springer Verlag for their friendly cooperation, which led to the present result. Finally, I have a personal favor to ask. It is important to me that this work should continue to be expanded and refined. In this, valued readers, I would sincerely welcome your help. I ask that you send technical notes and suggestions for improvement to the following email address: [email protected]. The more specific your comments are, the easier it will be for me to understand their implications, and possibly incorporate them in future editions. If you should discover inconsistencies in the content, or if you would like to applaud my efforts, I ask that you send all such messages to the same email address. And now I wish you much enjoyment reading this booklet the Entire vehicle. Stuttgart-Untertürkheim August 2015, February 2019

Michael Hilgers

Contents

1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 History. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 A Few Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2.1 The Coordinate System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 Trucks as Investment Goods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1 The Application. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2 Profitability of the Commercial Vehicle. . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.2.1 Optimizing Income . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.2.2 Costs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.3 Trucks from the Driver’s Perspective. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.4 Customer Purchasing Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3 Entire Vehicle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3.1 The Vehicle Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3.1.1 Tractor Unit or Truck. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 3.1.2 Vehicle Configuration and Operating Case. . . . . . . . . . . . . . . . . . . 19 3.1.3 Effects of Production on the Vehicle Concept. . . . . . . . . . . . . . . . . 20 3.2 Legal Framework Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 3.2.1 Emissions Regulations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 3.2.2 Weight and Size Regulations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3.2.3 Safety Regulations in the U.S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.3 Vehicle Variants. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 3.3.1 Axle Formulas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 3.3.2 Geometry of the Vehicle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 3.4 Driving Resistance and Longitudinal Dynamics. . . . . . . . . . . . . . . . . . . . . 35 3.5 Lateral Dynamics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 3.6 Weight of the Entire Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3.7 Comfort . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 3.7.1 Ride Comfort. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

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Comprehension Questions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Abbreviations and Symbols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

1

Introduction

Commercial vehicles move over 10 billion tons of freight in the United States every year [7]. These include finished products that consumers sees directly, such as bread for your sandwich, but also intermediate products that are used to make the finished products, such as the flour delivered to the baker several days earlier. Refuse vehicles then regularly collect trash, scrap paper and organic waste. The free availability of goods depends on road-based goods transport using trucks and transporters (Fig. 1.1). Commercial vehicles contribute significantly to our high standard of living. Our goods are also transported by rail and inland watercraft, but only the commercial vehicle, which can travel on roads, has a network that is extensive enough to meet our supply needs. Do you know of a supermarket with its own railhead? Transporting goods by commercial vehicle is also very efficient. Technically, trains travel at the same speed or even faster than commercial vehicles. With that said, the average speed by rail from the shipping point to the recipient by rail are discouraging slow in nearly every country. On the other hand, over long distances and when the goods involved are ­non-perishable, non-urgent, bulky and/or very heavy, the advantages of transporting by rail or barge are undeniable. The intercontinental traffic of goods that characterizes our globalized economy is assured to a large extent by large sea-going ships.

1.1 History The truck is almost as old as the car. It was logical to extend the advantages of the automobile to move goods as well. The first truck was built by ­Daimler-Motoren-Gesellschaft in Cannstatt, Germany in 1896, 10 years after the first

© Springer-Verlag GmbH Germany, part of Springer Nature 2021 M. Hilgers and W. Achenbach, Entire Vehicle, Commercial Vehicle Technology, https://doi.org/10.1007/978-3-662-60766-4_1

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1 Introduction

Fig. 1.1   Trucking moves america forward campaign, american trucking association

appearance of the car [8]. The vehicle had a payload of 1.5 tons (t) and an unladen weight of 1.2 t. Driving power was supplied by a 4-horsepower, two-cylinder engine [9]. None of those first trucks exist today. Figure 1.2 shows a commercial vehicle which was produced two years later, which is now the oldest commercial vehicle still in existence.

Fig. 1.2   The oldest truck powered with an internal combustion engine still in existence, produced in 1898. The engine is located under the driver’s seat and the cargo area (underfloor). With a displacement of about 1.51 it delivered approximately 5.6 horsepower (4.1 kW). It was capable of carrying a payload of 1250 kg. The vehicle is on display in the Mercedes-Benz Museum in Stuttgart, Germany. Photo: Michael Hilgers

1.2  A Few Terms

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The first trucks were intended for use in agriculture, as is revealed in this advertising copy produced by the Daimler-Motoren-Gesellschaft for the Cannstatt Festival of 1897: A Daimler is a useful beast, it pulls like an ox as all can see; It eats no hay at the end of the day and only drinks when work is going well; it threshes and saws and pumps for you, and will work when cash is tight, as often happens; It never suffers from foot-and-mouth and does not play mischievous tricks. It does not answer back in anger, it will not consume your precious corn. So buy yourself a workhorse like this, and you will want for nothing more.

However, the advantages of the truck were also very soon recognized by other companies wanting to transport heavy goods quickly and reliably – such as breweries1 or flour mills. Nowadays, trucks have made their mark in every last corner of the world.

1.2 A Few Terms A great deal of effort has been expended in defining various terms for regulations and standards. I try to avoid that. But it is helpful to define exactly what is meant by some terms from the outset. This is my short version: • A vehicle is anything that travels. • A motor vehicle is a vehicle with its own source of driving power which is not restricted to a track (no rails, etc.). • An automobile (motor vehicle) is a multitrack motor vehicle (a motorcycle, e.g., motorbike is single-track). • Trailers are vehicles without their own drive system. • Semitrailers or semi-trailers are trailers whose considerable portion of the weight is supported by the tractor vehicle and that are connected to the tractor by a fifth wheel coupling.

1One

is reminded of the imposing brewery drays pulled by as many as six horses, which had to be fed, groomed and trained!

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1 Introduction

Fig. 1.3   Coordinate system as used in commercial vehicles: The x-direction is the direction of travel of the vehicle. The axis that projects vertically is the z-axis and the y-axis is determined consequently as projecting transversely to the vehicle, from the right side to the left

• Tractors are motor vehicles which pull a trailer. • A commercial vehicle is designed for the commercial transport of passengers or goods and has a permissible gross vehicle weight of more than 3.5 t.2 • Goods vehicles are commercial vehicles which are used for the transport of goods. All other terms will (hopefully) be explained by the text.

1.2.1 The Coordinate System In engineering we need a coordinate system. In this book, the coordinate system is fixed relative to the vehicle, as shown in Fig. 1.3: The direction of travel is the positive x-axis.

2According

to this definition, taxis in the form of cars are not commercial vehicles.

1.2  A Few Terms

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The z-axis is perpendicular to the ground plane and points upwards. Since we technology professionals use the conventional, three-dimensional, right-handed coordinate system, the y-axis is fixed: The y-axis is projected parallel to the axles of the vehicle. The positive direction of the y-coordinates progresses from the right to the left side of the vehicle viewed in the direction of travel. This coordinate system is basically standard in the technical literature. For rotational movements about the axes, the following technical terms are used: rotation about the vertical axis (z-axis) is called yaw, rotation about the longitudinal axis of the vehicle (x-axis) is called roll and when the vehicle rotates about the y-axis, we refer to it as pitch.

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Trucks as Investment Goods

The range of activities in which trucks are used is enormous. But wherever they are used, all of these activities share a common element: the truck is an asset used to earn money, either directly or indirectly. The traditional carrier earns its money directly from moving freight, using a truck as an asset. In the vocational segment, businesses make money providing a different service, in which the truck is only the instrument to deliver the service. Examples of this would be a mobile concrete pump, a roadsweeping machine, a refuse collection vehicle, or a crane mounted on a truck chassis. The gardener or tradesman who drives a truck also belongs in this category. In these cases, the end product is not the transport of goods; but without the truck it would be incalculably more difficult to deliver the requested service. In this case as well, the truck falls under the heading of an asset. The huge variety of tasks involving the use of a truck has led to the development of a plethora of specialized vehicle models, designed specifically to carry out a respective task. The various vehicle manufacturers already produce a considerable number of different vehicle types. Specialization is then further refined by the truck equipment manufacturer, sometimes also called body builder, who installs the body on the manufacturer’s road-ready vehicle. Sometimes the body is much more expensive than the basic vehicle. See also [6].

© Springer-Verlag GmbH Germany, part of Springer Nature 2021 M. Hilgers and W. Achenbach, Entire Vehicle, Commercial Vehicle Technology, https://doi.org/10.1007/978-3-662-60766-4_2

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2.1 The Application The enormously-varied range of applications the truck is expected to perform is reflected in the variety of different vehicles. Certain applications require highly specialized vehicle bodies, or trailers. For example, there are tankers for petroleum products as well as for food), vehicle carriers, cement mixers, road sweepers, construction material transporters with loading crane, logging trucks, dumpers, container trucks and many more (Fig. 2.1). The closest thing to a standard vehicle is the tractor-trailer combination. A tractor pulls a number of different trailers and so it affords a certain amount of flexibility. This is why in the US as well as in Europe, tractor-trailers account for the largest percentage of new vehicles in the heavy commercial vehicle segment. The proportion of vehicle registrations of tractor-trailers is growing. The standard semitrailer is a trailer with tarp or box body. More and more tractor-trailer combinations are also used on construction sites, pulling semitrailers with a dump box. Besides the load that is actually transported, the application is also defined by other criteria, for example, the route: Does the load have to be transported through the city or hauled over long distances on major roads? Is the route flat and undemanding or is it hilly? Perhaps the vehicle must even travel off-road? Both the load and the transport route are being considered to find the best vehicle configuration and successfully complete the transport task as economically as possible. This brings us neatly to the next section in which we talk about profitability.

Fig. 2.1   Examples of various applications in highway, vocational and medium duty market segments

2.2  Profitability of the Commercial Vehicle

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2.2 Profitability of the Commercial Vehicle The purpose of a commercial vehicle is to earn money. The profit is calculated by subtracting costs from income. Therefore, the vehicle operators wants a vehicle that enables them to perform many, well-paid transport tasks all the while incurring the lowest possible costs.

2.2.1 Optimizing Income The correct vehicle and vehicle equipment help the carrier or vehicle operator to increase his income. There are operations that must be billed according to the mass of the cargo transported. These may involve bulk materials or construction materials (cement truck). The right vehicle for these tasks is a payload-optimized vehicle with low unladen weight in which the carrier can transport the largest possible (paid) quantity of cargo. Other operations are paid according to volume, so in these cases the carrier is interested in being able to transport the greatest volume possible. For this, there are vehicle concepts which maximize freight volume, such as low-frame vehicles (lowliners), extended length semitrailers (special permit required) or articulated trains with ­low-mount coupling systems. Since the carriers can generate additional income with each trip, it is in their best interest to complete individual load assignments as quickly as possible. Here, too, they are helped by vehicle technology: Semitrailer and bodies that are optimized for the cargo in question facilitate fast loading and unloading, so the vehicle is soon back on the road again. Navigation systems reduce out-of-route miles and help the driver to choose the quickest route or avoid traffic jams. Depending on the situation, it may be worth opting for high engine power so that the resulting high average speeds enable a high customer turnover for the operator or to take on heavy hauls. Wear-free permanent brakes (retarders), which enable safe downhill driving, might help drivers to achieve higher transport speeds. Another highly effective optimization strategy is to avoid having to make empty trips and to transport return cargo whenever possible. When (paid) cargo is transported on both the outbound and the return journeys, this is called backhauling. If this does not happen, it is called deadheading. Vehicle technology helps to move the vehicle with loads on both the outward and return journeys as often as possible, for example, by using the above-mentioned flexible semitrailer that are suitable for various types of cargo. Another way to optimize revenue is to specialize. If a transportation company gains a reputation as a specialist in certain tasks, it becomes easier to receive orders in this segment. It also happens that in certain segments of goods transport, the cargo rates that can be commanded may simply be higher than in other segments. Specialization may be

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associated with the goods that are being transported (fresh products, heavy loads) or with certain destinations. Finally, certain soft factor that can contribute to revenue optimization should also be mentioned: A visually appealing vehicle fleet may convince more prospects to decide to work with a given transportation service provider. A modern vehicle – perhaps even of a certain brand – can enhance a company’s image and indicate that the customer has found a highly capable contractor. This effect is as important for the gardener or tradesman whose customers are the end consumer as it is for multinational freight forwarding companies that wish to project a vital, high-performance organization.

2.2.2 Costs Besides optimizing income, the second approach is to reduce the costs of operating the vehicles. Expenses of a long-distance haulage company are listed in Fig. 2.2. Figure 2.3 shows a comparison of the various cost elements. The breakdown of costs shown here represents a sample of motor carriers in North America over a five-year span. The cost structure varies based on industry sector, size of fleet, type of operation, region and average age of equipment. The distribution of costs also changes constantly due to relative price fluctuations over time, particularly in driver wages and benefits, and fuel. Different trucking companies may have different cost ratios, even if they hauls similar freight.1 Driver wages and benefits The driver accounts for a large portion of the costs including wages, benefits and bonuses. This is primarily due to an aging demographic and a continued shortage of qualified drivers. Loss of value, depreciation In typical long-haul businesses, the procurement costs, or the loss of value (depreciation) of the vehicle represent only a small part of the total costs. Loss of value consists of a time-dependent component (the vehicle ages) and a usage-dependent component (the vehicle wears out). The residual value that can be recouped at the end of the planned

1Example:

A fictitious transportation company A attaches great importance to the latest technology and well-trained drivers. Fictitious transportation company B pays its drivers less, and they are therefore less well trained, change employers more frequently and take less care to drive in a way that conserves materials. Company A will presumably have somewhat higher expenses for the driver and depreciation, whereas company B will spend more money on fuel, repairs and maintenance. Both companies may transport the same goods and both can operate successfully on the market.

2.2  Profitability of the Commercial Vehicle

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Mileage-related depreciation (wear and tear) Fuel costs

Variable costs

Other operating materials (DEF*, windshield washer fluid, etc.)

Costs of vehicle operation

Lubricants (oil and grease) Maintenance and repair (incl. replacement parts) Vehicle cleaning Cost of tires Mileage-related road use (tolls) -- Other -Expenses

Driver costs

Surcharges Social security payments

Vehicle fixed costs

Wages Time-related depreciation Third-party financing costs (interest, leasing payments)

Cost of vehicle ownership

Road tax Time-related road use fee (vignette, or road tax) Insurance Inspection fees Parking costs

Company fixed costs

Administrative personnel costs Office rental

Administration costs

Office materials, communication costs, etc. Insurance (non-vehicle related) Contingency costs (payment default, uninsured damage, etc.) Consultancy costs, premiums and commissions -- Other --

Imputed employer's salary

Fig. 2.2   Expenses for global consideration of a long-distance haulage company (*DEF = Diesel Exhaust Fluid)

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useful life of the vehicle reduces the degree to which procurement costs play into the total costs situation. In total, the procurement price of the truck is not a dominant factor in the total cost consideration over its entire service life.2 Of course the costs for the body, which on vocational vehicles may be several times greater than the vehicle costs, must also be taken into account. Financing costs Besides the loss of value the vehicle undergoes, the interest and charges the carrier has to pay to purchase a vehicle must also be considered. If the vehicle is paid for directly from company capital, without financing, imputed interest must be taken into account to reflect the fact that the money might have realized a profit if it had been used elsewhere. For example, instead of buying the truck, the company could have left the cash in its bank account and reaped the benefits of the interest.3 For readers who would like to learn more about this, these are also referred to as opportunity costs. Repairs and maintenance In a typical motor carrier, maintenance and repairs make up about 9% of total costs. Repair and maintenance costs fluctuate in proportion to vehicle utilization. The more intense and the longer the vehicle is utilized, the greater the wear and tear. Both cost types can also be significantly influenced by the driver. A driver who drives smoothly subjects the equipment to less stress, thereby reducing both maintenance and repair costs. Accidents for which the driver is responsible are reflected directly in this cost category. Various driver assistance systems designed to reduce the likelihood and seriousness of an accident have the capability to lower repair costs. Lastly, a labor shortage of repair technicians in the United States have also driven up repair costs over time. The vehicle owner can also enter into a service contract instead of having to include the maintenance costs in his cost calculations. These service contracts are offered by the vehicle manufacturers and provide customers better certainty. Then, instead of the maintenance costs, the cost calculation must reflect the costs of the service contract as well as any costs were not covered by the service contract. In the event of unscheduled repairs, additional costs may arise besides the costs of the repair, such as the cost of a replacement vehicle.

2In

this context, one often speaks of, = Total Cost of Ownership (TCO). This describes the total costs over the period of use of the vehicle. 3In light of the interest rates in recent years, a rather doubtful pleasure.

2.2  Profitability of the Commercial Vehicle

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Tires Tires represent an astonishingly significant expense for the truck company. They become worn and must be replaced in good time. Unfortunately, the individual tire is quite expensive, and many of them are needed all at the same time: a standard tractor semitrailer combination needs ten tires for the tractor and another four for the semitrailer, and possibly a complete set of winter tires. And tires not only represent a cost factor in and of themselves, they also affect the fuel costs [4] through rolling resistance. Vehicle insurance and road tax For the sake of completeness, insurance and road tax expenses are also listed here. The good news is that the associated costs are easy to calculate. They are unavoidable. At the same time, road tax is fixed nationally, so it differs from one country to another. Fuel consumption Fuel consumption represents the second largest cost in long-haul operations (see Fig. 2.3). The volatility in prices over time make fuel a highly monitored topic. As a result, reducing fuel consumption of vehicle operations is of particular interest amongst fleets. That is why an entire book in this series is dedicated to the topic of fuel consumption [4]. Ultimately, the most critical figure for the carrier is the specific fuel economy, or freight efficiency, per transported unit. If the carrier reaches the load limit for his vehicle sooner, consumption per transported unit of weight is the parameter of interest. Freight efficiency is typically expressed as ton-miles per gallon. However, there are also loads in which the vehicle has not reached its limits in terms of transport weight but rather volume. When assessing these kinds of transport tasks, the decisive value is consumption

Fig. 2.3   Breakdown of motor carrier operational costs in the US according to [10]

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per transported cubic meter of capacity. Fully utilizing all available cargo volume is known as cubing-out. This is why long combination vehicles are a topic of discussions on fuel consumption optimization and CO2 reduction. Besides fuel, the truck also consumes engine oil, lubricants and – if it conforms to modern emission standards – Diesel Exhaust Fluid4. Besides the above, windshield washer fluid also has to be added according to consumption, and coolant according to the maintenance schedule. However, compared with the cost of fuel, these consumables are practically negligible. Road use charges Excise taxes are paid on both the federal and state level for fuel consumed by all motor vehicles. The revenues raised from taxation largely fund the maintance and buildup of transportation systems inlcuding highways and bridges the vehicles use. Commercial vehicles have large fuel capacities – typically up to 300 gallons – and can travel across several states between fueling. This situation poses problems, since the collection of taxes and the use of roads often occur in different states. To ensure the collection of state tax revenues is distributed to states where the roads are used, motor carriers are required to submit fuel tax reports. The reports detail the miles a vehicle drives state by state to determine where to distribute tax revenue. This mechanism ensures highway funding is proportional to road use. In other countries (e.g. Europe, Japan) trucks – and in many cases cars – must pay a distance-dependent charge for using parts of the highway network. This toll might represent a quite substantial portion of the total costs of long-distance haulage. Safety, comfort and cost Safety systems may be designed to reduce a vehicle operator’s costs. Most accidents lead to repair costs and a reduction in the vehicle’s value. Additional costs also arise, such as extra costs for a replacement vehicle, and in the worst case if the driver is injured, health care costs and the cost of a substitute driver. Accidents for which the driver is responsible lead to an increase in insurance costs. An accident also negatively impacts the carrier’s adherence to delivery dates and thus also customer satisfaction. Comfortable vehicles can help to reduce costs for similar reasons to safety systems. If the driver is rested and driving in a comfortable vehicle, he or she will drive more safely, and statistically should be involved in fewer accidents. But the more important argument

4Diesel

Exhaust Fluid (DEF) is an aqueous urea solution which is stored in a separate tank in the vehicle and injected into the exhaust system to extract the pollutant nitrogen oxides from the engine exhaust in the catalytic converter and convert them into water vapor and harmless nitrogen.

2.4  Customer Purchasing Criteria

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is that the driver of a comfortable vehicle is more relaxed and drives more smoothly and more attentively, which is more fuel efficient, and consequently generally more economical. Experience has shown that many drivers not only take better care of vehicles they like but also drive them more carefully.

2.3 Trucks from the Driver’s Perspective Apart from the perspective of the motor carrier, who considers the truck as an investment and a machine for earning money, the truck must also meet the needs of the driver. The driver spends many hours in the vehicle and often forms an emotional bond with it. Since good drivers are important to the freight forwarder and should be encouraged to stay with the company, it is important for the vehicle to satisfy the driver’s requirements as well. Or, to put it bluntly, the truck manufacturer has two customers: the freight forwarder (the purchaser) and the driver (the user)! The driver’s assessment of his or her vehicle is particularly important in long-distance haulage. In long-distance haulage, apart from purely driving time, the driver often also remains in the vehicle during moments of free time, recreational phases and sleep. The cab serves as both living and sleeping quarters [5]. According to various studies (for example, [11]), it is becoming more and more difficult to find people who are interested in a career. In view of this trend, it is all the more reason to address the driver's needs regarding the long-haul vehicle. Many freight forwarding companies now take into account drivers’ opinions on different vehicles and equipment variants when considering the purchase of new vehicles. Moreover, as a result of demographic changes and the increasing age of drivers, it is becoming increasingly important to ensure that vehicles and trailers, or bodies, are ergonomically optimized and can be operated with minimum physical effort. Loss of flexibility typically takes place in people much earlier than loss of bodily strength. In distribution haulage, the vehicle is usually less important to the driver, since it is perceived solely as a piece of equipment. The driver’s right to express opinion regarding the purchase of vehicles is of even less importance. Even so, the vehicle manufacturers go to great lengths to accommodate drivers’ needs as diligently as possible in distribution vehicles.

2.4 Customer Purchasing Criteria In summary, the criteria the customer applies when choosing the right vehicle falls into three groups – similarly to the three Sects. 2.1 to 2.3 above: the suitability of the vehicle for the specific transport task, consideration of the total costs over the service life of the vehicle and soft factors.

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2  Trucks as Investment Goods

Vehicle Ancillary criteria • Financing offer

• Brand loyalty • Consulting and customer support by the salesperson

• Manufacturer's workshop network • Own workshop's expertise • Availability of replacement parts

TCO of the vehicle • Fuel consumption • Purchase price and projected resale price • Costs of repair & maintenance

Safety • Comfort • Driving feel • Appearance/Appeal and design

Suitability of the vehicle for purpose • Volume • Payload • Suitability for special body • Off-road capability E m nvir co enta onm bil pa l ity ti-

Soft factors

Fig. 2.4   The criteria a customer applies when purchasing a truck can be summarized in three groups: total costs over the period of use (TCO), suitability for the intended transport task and soft factors such as comfort. Besides these three groups of criteria, which directly describe the vehicle, the decision to purchase is typically influenced by other, more broadly related factors such as the workshop network

Figure 2.4 illustrates these three groups and lists the most important specific purchasing criteria. It is of course possible that the relative importance of the criteria may vary for different purchasing decisions. Besides the criteria relating directly to the vehicle, there are other criteria that can significantly affect the decision to make a purchase. These are, for example, the workshop network, the customer’s own ability to repair a given brand, or even interpersonal criteria such as the relationship between the buyer and the truck salesperson.

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Entire Vehicle

The vehicle manufacturers normally organize their development areas according to their assemblies. There is one area dedicated to the engine, another which makes the axles or develops the cab, and so on. The supplier landscape has also evolved over decades to reflect a breakdown of the vehicle according to assemblies and components. ­Well-respected companies have cultivated their core competence in, for example, vehicle electronics or transmission building. And this logical and traditionally usual separation organization of the vehicle into assemblies is also reflected to some degree in this series of booklets. But this chapter is concerned with the vehicle as a whole. The customer buys an entire vehicle and expects it to have certain characteristics and be suitable for use in certain situations. For the user of the vehicle, the commercial benefit of the vehicle is of utmost importance – as the name commercial vehicle implies. The vehicle is evaluated in its entirety and is perceived by the customer as such. The customer is primarily interested in whether the vehicle is able to carry out the intended transport task. While the engineer takes great pleasure in the individual technical refinements, the customer often finds them irrelevant. A truck consists of several thousand parts, as is illustrated in Fig. 3.1. These must all fit together to form an efficiently functioning entire vehicle. What the individual assemblies and component parts are expected to contribute can be derived from the requirements the entire vehicle must satisfy and its intended purpose.

3.1 The Vehicle Concept The vehicle concept defines the basic mechanical concept, the dimensions and the positioning of the components in the vehicle. The cab concept is visually striking in particular: conventional or cab-over-engine? This question, or at least the question of

© Springer-Verlag GmbH Germany, part of Springer Nature 2021 M. Hilgers and W. Achenbach, Entire Vehicle, Commercial Vehicle Technology, https://doi.org/10.1007/978-3-662-60766-4_3

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4x2 standard tractor

Parts to be installed*

1000 1000 2000

Front and rear axle Transmission Engine

3200

Cab

4500

Chassis

Approx. 12,000

Different parts

8x8 all-wheel drive dumper

Parts to be installed*

5000 300

500

700 1600

Different parts

Driven front and rear axles and through-drive

1000 1500

Transfer case

2000

Engine

2600

Cab

7000

Chassis

1500

300 600

Transmission

700 1350

1600 1900

Approx. 4,700 Approx. 19,000

Approx. 6,500

* Number of parts to be installed from the point of view of the OEM. Many components are delivered as pre-assemblies by the supplier. The number of parts hence depends on the OEM's vertical integration.

Fig. 3.1   Estimated number of parts from which a truck is built in the vehicle manufacturer’s factory. Components that are delivered to the vehicle manufacturer (OEM) as assemblies are considered as single parts, even if the assembly itself consists of many individual components, for example, the seat. Some parts are installed in several different positions. Therefore, the list also shows how many different parts are assembled to build the truck

which cab predominates in a given region, is heavily influenced by legal regulations. This will be discussed later (Sect. 3.2.2). Despite the enormous variety of available vehicles and the fact that in some cases commercial vehicles have been massively adapted for their specific work purpose, some basic constants still apply to the concept of modern commercial vehicles. Trucks have a ladder-type frame as the supporting structure. In North America, a cab is mounted on the frame with an isolation system just behind the engine. In other regions, a sprung cab is mounted on the front of the frame just over the engine. The useful area is in the rear. The drivetrain arrangement is the same in all trucks: all trucks have a front-to-rear installation, the engine is mounted in the front, which is the best position for cooling, and drives at least one rear axle, or sometimes several axles. The engine crankshaft runs parallel to the longitudinal axis of the vehicle. The transmission is mounted behind the engine. Other vehicle concepts

3.1  The Vehicle Concept

19

such as front-wheel drives, transverse-mounted engines, underfloor engines and transaxle configurations are not used at all in trucks. Buses are different in that they can have many different drivetrain configurations. In the standard large European bus the engine and transmission are mounted behind the rear axle; and the engine can be mounted lengthwise or transversely. The rear engine placement is favorable for configuring the driver cockpit and access options, and can be adapted well to the passenger area. By its nature, the cooling of the engine is a bit more complicated. In small buses, the engine is often located at the front like a truck. All trucks and buses have double-pivot steering (Ackermann-steering).

3.1.1 Tractor Unit or Truck Truck transportation is divided into two transport concepts. First there is the tractor unit, which has no cargo area or other useful area of its own. The tractor is intended to pull a semitrailer, and is only suitable for transporting goods in combination with said trailer. Then there is the truck with a cargo area or body.

3.1.2 Vehicle Configuration and Operating Case Besides the basic choice between a tractor-semitrailer combination and a truck-trailer, the carrier’s decision for the right vehicle is determined by many other parameters as well: • The cargo the vehicle is intended to carry (the nature of the cargo and the total load capacity). Obviously, a vehicle for transporting lumber or logs should be configured differently from one that will spends its operating life making deliveries to newspaper stands in the heart of the city. • The terrain the vehicle will have to negotiate. • The condition of the infrastructure within its operating range. • The climatic conditions in which the vehicle will operate. • The length of the routes and the total annual mileage planned for the vehicle. • The amount of traffic and routes it will travel (Are there many bends? How often will the vehicle accelerate and brake?) The congestion in Asian conurbations is undoubtedly one of the reasons why a typical light-duty truck is much more widespread there than in Europe or the US. • The customer segment the vehicle is intended to address. • Treconceived expectations in specific markets. Even historically-developed market preferences contribute to the fact that vehicles in different countries look different. • The legal provisions in the countries where the vehicle is to be registered and operated.

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Table 3.1  Reference value for the use of commercial vehicles in various segments Vehicle segment

Average speed

Total mileage over the service life of the vehicle

Annual mileage

Long haul trucks

62 mph

1 million miles

120,000 miles

Distribution trucks

40 mph

300,000 miles

30,000 miles

Cars

60 mph

120,000 miles

12,000 miles

[15] shows examples of how the various parameters of vehicle usage are considered in order to assemble the right vehicle for the customer. Period of use, average speed and product service life can greatly differ according to the segment in which the vehicle is used. Table 3.1 illustrates the vastly different usage profiles of motor vehicles with reference to operating years and miles traveled.

3.1.3 Effects of Production on the Vehicle Concept Besides the determinations that are of importance for the user, the vehicle manufacturer makes additional concept decisions while developing the vehicle. These include ­production-driven considerations which do not affect the customer. One important criterion for production is that it must be possible to manufacture the vehicle inexpensively and reliably. Some vehicles and their production concepts are produced in low volume and as a consequence the technical product concepts might differ from vehicles that are produced in large numbers. The vehicle manufacturer also ensures that an additional product is compatible with its own product portfolio and shares as many common parts with the existing products.

3.2 Legal Framework Conditions The legal provisions that have had the greatest impact on American vehicles have been the emission regulations, including tailpipe emissions of criteria pollutants (pollutants known to cause health or welfare problems) and of greenhouse gases (GHGs). Additionally, regulation of On-Board Diagnostic (OBD) systems to monitor those gaseous emissions have driven significant engineering effort. Similarly, size and weight regulations have driven the vehicles’ configurations; and safety regulations impact the designs of many vehicle systems and components. The following sections will address each of these areas of the regulations and will describe how manufacturers comply to the regulatory requirements.

3.2  Legal Framework Conditions

21

3.2.1 Emissions Regulations United States Environmental Protection Agency (EPA), California Air Resources Board (CARB), and Environment and Climate Change Canada (ECCC) regulate criteria pollutants from the engines used in heavy-duty vehicles. The engines are tested and certified on engine dynamometers in certified laboratories. The engines are then driven over prescribed test cycles: the Federal Test Procedure that simulates transient driving in stopand-go situations and the Ramped Modal Cycle that simulates steady state driving and a variety of speed and load points. The engines’ emissions must be below prescribed levels that have ratcheted down over time. The most important emissions are nitrogen oxides (NO and NO2, jointly referred to as NOx) and particulate matter, which includes soot and ash, as well as the material adsorbed on the surface of the soot and ash, all of which are jointly referred to as PM, or particulate matter). Technologies to tune an engine to reduce PM emissions have normally increased NOx emissions and vice versa; only with the invention of exhaust gas aftertreatment equipment have manufacturers been able to lower both pollutants’ emissions simultaneously. The ratcheting down of the NOx and PM is shown in Fig. 3.3:

Fig. 3.2   Legally regulated outer dimensions in the United States for width (top right), tractor semitrailer (top left) and double trailers (bottom)

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Fig. 3.3   US emission legislation for NOx and PM

Additionally, CARB limits NOx emissions from engines during idling. The Clean Idle certification requirement limits emissions to 30 grams of NOx per hour during a prescribed idling test, or else the engine must shut down within five minutes of beginning to idle. Future regulations will involve much more stringent NOx regulations and requirements that NOx aftertreatment systems be demonstrated to function properly for much longer lifetimes than today. CARB regulates OBD systems, and the other agencies – EPA and ECCC – require CARB OBD certification. To get OBD certification, an engine must monitor dozens of controls that keep engines compliant with criteria pollutant emissions. This includes exhaust gas recirculation systems, which help keep combustion temperatures low and thus help minimize NOx formation, and particulate filters, which trap PM. To obtain OBD certification, engines must also monitor the engine’s diagnostics that keep it performing properly, including tailpipe NOx sensors. Within the OBD regulations is a catch-all that requires monitoring for the malfunction of any electronic powertrain component/system not otherwise described in the regulations that provides input to (directly or indirectly) or receives commands from the on-board computer(s), and can affect emissions during any reasonable in-use driving condition or) is used as part of the diagnostic strategy for any other monitored system or component. OBD systems must be tested and demonstrated its capability to discover faults, even when the engine has aged several years. CARB regularly audits in-use vehicles by triggering faults; if an engine’s OBD system fails to properly detect the faults, then the manufacturer may be forced to recall and fix all such engines. Since 2012, the EPA, CARB, and ECCC have regulated greenhouse gases (GHGs) and fuel consumption. Vehicle GHG emissions are primarily related to fuel consumption, that is the burning of fuel produces carbon dioxide, the primary GHG, such that fuel consumption and GHG emissions rise and fall with each other. CARB initially

3.2  Legal Framework Conditions

23

regulated by requiring SmartWay certification, a previously voluntary certification that proved a vehicle used some fuel saving technologies like aerodynamic chassis fairings. Now, the three agencies require that each vehicle’s GHG emissions be below a certain level. Because there are so many variants of trucks and tractors, the agencies provide a regulatory GHG simulation tool called the Greenhouse Gas Emissions Model, or GEM, which takes inputs such as aerodynamics and tire data to simulate vehicles’ performance on regulatory drive cycles. From 2012 to 2020 (Phase 1 of the GHG regulations), the standards were relatively loose and required only a few technologies to comply, mainly aerodynamics and tires. In 2021, Phase 2 of the agencies’ program will start, when the standards get significantly more difficult and require many more technologies to comply, including transmission optimization, powertrain downspeeding, eCoast, and more. A manufacturer is required to show that, at the end of each year, the manufacturer’s fleet on average complies. Individual vehicles may exceed the GHG emission limit as long as other vehicles make up the deficit. Along with the fuel consumption aspect of GHG emissions, the agencies have regulated air-conditioner (AC) leakage. In Phase 1 of the GHG regulations, only tractors were regulated. In Phase 2, all vehicles will be regulated, including vehicles built in stages by multiple manufacturers, such as the custom chassis that get sent for body upfitting with outside companies. The manner of certification is that the completed vehicle’s AC system must emit less than 1.5% per year of AC refrigerant, when simulated through a Society of Automotive Engineers procedure called SAE J2727. This procedure tallies all the AC items on a vehicle and applies industry-accepted values for the leakage from each feature, for example, one dual-piston compressor, two meters of steel lines, etc. with X emissions per compressor and Y emissions per meter of line. In addition to these regulations, vehicles with volatile fuels (gasoline, natural gas, propane) are subject to evaporative, refueling emission limits. Evaporative limits involve testing a vehicle in an environmental shed that simulates several days of daytime heating and nighttime cooling. The agencies limit the amount of fuel emitted with the air that is breathed into the fuel tank when the hot in-tank air cools and is then expelled when the air rewarms. Refueling limits involve testing the amount of fuel vapor pushed out of the tank when liquid fuel is pumped in during refueling. The agencies limit the amount in a way that fuel tanks must trap fuel vapors. Because diesel has very low volatility – meaning that its fuel creates very little vapors – essentially no limit applies. All of these emission regulations are enforced through type certification, which means that manufacturers must perform testing and submit to the regulatory agencies evidence of passing the tests, at which point the agencies give certificates that allow manufacturers to introduce their products into commerce. The agencies may (and frequently do) audit certified products. If the agencies find noncompliances, they may demand that the engines or vehicles be recalled and brought into compliance. Or they may void a certificate, blocking a manufacturer from legally selling products. Emission legislation is enacted regionally. The strictest limits are imposed by emission legislation in Japan, the US and Europe. Other countries generally take their lead

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from those legislations with a certain time lag. Although the absolute limits in the leading markets look similar and are marching practically in lockstep towards ever stricter emission levels, the requirements actually imposed on engines and automotive technology vary quite a bit. This is because the test cycles implemented in Europe, the US and Japan are different.

3.2.2 Weight and Size Regulations In order to protect roadways and bridges, heavy-duty vehicles are subject to weight limitations per unit length, as well as their length, width, height, and the types of trailers they may pull. US weight laws are referred to as bridge laws, in that they protect bridges and involve calculation of the weight on any one bridge (combination of axles) within a vehicle. The bridge formula was introduced in 1975 to reduce the risk of damage to highway bridges by requiring more axles, or a longer wheelbase, to compensate for increased vehicle weight. The formula may require a lower gross vehicle weight, depending on the number and spacing of the axles in the combination vehicle. In order to comply, vehicles must limit overall weight and provide enough distance between axles to spread the weight across a large area of roadway. Compliance with the Federal Bridge Formula weight limits is determined by using the formula or table of Fig. 3.4. Beyond the limits of this formula, no single axle may support a gross load of more than 20,000 lb, no tandem more than 34,000 lb, and no vehicle (without a special permit) more than 80,000 lb. The vehicle with weights and axle dimensions shown in the Fig. 3.5 is used to illustrate a Federal Bridge Formula check. Before checking for compliance with the Federal Bridge Formula, a vehicle’s ­single-axle, tandem-axle, and gross weight should be checked. Here, the single axle (1) does not exceed 20,000 lb, tandems 2–3 and 4–5 do not exceed 34,000 lb each, and the gross weight does not exceed 80,000 lb. Therefore, these preliminary requirements are satisfied. Truck weight is regularly checked in the US (Fig. 3.6). In the United States and Canada, on-road vehicles are limited to 2.6 m, or approximately 102 inches width, with certain items exempted from consideration (including mirrors). Aerodynamic features that extend less than 3 inches from the side of a vehicle are not counted. In other countries, the width limits are more extreme and the exempted items more limited. For example, in Australia, the width limit is 2.5 m and aerodynamic features count in the width measurement. Similarly, vehicles are limited in length. In the United States and Canada, straight trucks are limited to 40 ft, and trailers are generally limited to 53 ft (with limited exceptions). Tractors’ lengths are generally not regulated, only the trailers. Certain types of trailers may be used in certain states, but generally a 53 ft trailer is compliant. Each state has its own rules and certain heavy-haul types of trailers are permitted in some states but

3.2  Legal Framework Conditions

25

Fig. 3.4   Bridge Formula and table to determine weight limits in the US

not others. These specifications are just a general rule of thumb and care should be exercised to ensure vehicles comply with the local requirements. Vehicles are limited generally to 13 ft six inches in height, except when granted with a special permits. Notwithstanding the height rules, what constrains the height of the vehicles many times is the height when piggy-backed for initial transportation. All of these regulations are enforced through roadside inspections. If a vehicle is found during a roadside inspection to be oversized or overweight for its size, then the

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Fig. 3.5   Illustration of a Federal Bridge Formula check for a tractor semitrailer

Fig. 3.6   Trucks entering weigh station for weight compliance check. (Photo: Derek Rotz)

vehicle inspector may ticket the driver or hold the vehicle, preventing further operation. Figure 3.2 illustrates the permissible outer dimensions in the United States. Conventional and cab-over-engine tractors in light of the length regulations As stated above, tractors’ lengths are generally not regulated in North America, only the trailers. Hence conventional tractors are widespread. The conventional vehicle ­(cab-behind-engine) has a number of advantages: It is easy for the driver to get into the cab, and the engine is readily accessible. One just has to just pop the hood, similar to a car. The installation position of the engine is also less constricted, which incidentally helps with cooling the engine. The complicated cab mounting (rotating at the front and detachable at the back) and the cab tilting mechanism of a cab-over-engine solution are not required. Naturally, the cab-behind-engine vehicle has a long wheelbase, and the

3.2  Legal Framework Conditions

27

Fig. 3.7   Two concept vehicles: a the Mercedes-Benz Future Truck from 2014 and b the Freightliner Inspiration Truck from 2015. Concept vehicle a is a cab-over-engine vehicle in which the cab sits above the engine. Concept vehicle b is a cab-behind-engine vehicle such as are commonly used in North American long-distance haulage. Photos: Daimler AG

driver is seated between the axles. This arrangement offers a good level of driving comfort and involves considerably less effort than with cab-over-engine versions, in which the driver’s seat is positioned over the front axle. In Europe, Japan and other regions of the world the cab-over-engine configuration is dominant. Cab-over-engine literally means that the cab is located over the engine. Figure 3.7. shows the difference between cab-over-engine and cab-behind-engine using the example of two concept vehicles.

Real Axle Loads in a Tractor Semitrailer Combination The axle loads in a tractor semitrailer combination can easily be calculated to a good approximation. The geometry of the trailer determines how the load is distributed over the axle group on trailer and the kingpin. The geometry of the tractor unit determines hows the fifth-wheel load is spread to the front and rear axles of the tractor. The decisive dimensions for these purposes are the wheelbase and the distance between the rear axle and the kingpin.1 Let us first consider how the gravitational force of the load FG bears on the fifth-wheel coupling and the rear axle group of the semitrailer (see Fig. 3.8). The torque balance at the contact point of the trailer axle group yields the following equation: FGS · l2 = FG · h1 (3.1) h1 FGS = FG · l2 1The

distance between the rear axle and the kingpin is the distance between the rear axle contact line and the vertical line through the kingpin (line of force application of the semitrailer) – see Fig. 3.8.

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13.60 m 12 m

l1

l2

l3

b1

Fs

b2

center of gravity of the load

FG

h1

Fs FVA s

FAA

FHA

r

Fig. 3.8   Calculation of axle loads for a tractor semitrailer combination

Accordingly, FGS is the component of the gravitational force of the load that is supported by the fifth-wheel coupling. h1 is the distance between the center of gravity of the load from the centerline of the rear axle group, and l2 is the distance between the kingpin (support point for the semitrailer load) and the centerline of the rear axle group. The gravitational force of the load on the Semitrailer axles is:

FGA = FG − FGS h1 = FG − FG · l2   h1 = FG · 1 − l2

(3.2)

Now the dead weight of the semitrailer must be assigned to the fifth wheel load and the rear axle group:

FAA

h1 FS = FFifth-wheel load EMPTY + FG · l2   h1 = FAxle load EMPTY + FG · 1 − l2

(3.3)

The fifth-wheel load bears on the tractor. The distribution to the front axle and rear axles of the tractor is calculated from the wheelbase r and the distance between the rear axle and the fifth wheel kingpin s on the tractor unit:

3.2  Legal Framework Conditions

FFifth-wheel load FA · r = FS · s s FFifth-wheel load FA = FS · r

29

(3.4)

The portion supported by the rear axle is:

FFifth-wheel load RA = FS − FFifth-wheel load FA s = FS − FS · r   s = FS · 1 − r

(3.5)

Adding in the tractor yields:

FHA

s FVA = FFront axle EMPTY + FS · r  s = FRear axle EMPTY + FS · 1 − r

(3.6)

3.2.3 Safety Regulations in the U.S Three types of laws regulate heavy-duty vehicles’ safety in the United States: Federal Motor Vehicle Safety Standards (FMVSSs), Federal Motor Carrier Safety Regulations (FMCSRs), and product liability law. FMVSSs are rules that apply to new vehicles at the time the vehicles are introduced into commerce; vehicle manufacturers must certify that the vehicles comply with the safety standards. FMCSRs are the rules that apply to in-use vehicles. If a government vehicle inspector finds that a vehicle does not comply with a FMCSR, the inspector may deem the vehicle improperly maintained and may ticket the vehicle operator. Lastly, product liability law is the set of rules developed through court cases where plaintiffs have alleged that a vehicle manufacturer or operator was negligent in designing, manufacturing, or maintaining a vehicle even if the vehicle complied with all FMVSSs and FMCSRs. In turn, FMVSSs and FMCSRs define the floor or the minimum requirements but not necessarily everything should be done. Canada uses very similar regulations; its manufacturer rules, the CMVSSs, mirror the US FMVSSs albeit with some additional requirements like displaying kilometers per hour on speedometers and illuminating daytime running lights. FMVSSs FMVSSs (and CMVSSs) define requirements for a large number of safety systems. General ideas behind the rules include making vehicles safe in braking events (FMVSS 121), making them safe in aggressive turns (FMVSS 136), providing adequate lighting and providing uniform messaging through exterior lighting (FMVSS

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108) and uniform messaging through the symbols displayed on instrument clusters in various vehicles (FMVSS 101), preventing rapid expansion of fires if a fire occurs (FMVSS 302), and more. Below is a list of some of the FMVSSs relevant to heavy-duty vehicles: § 571.101 Standard No. 101; Controls and displays. § 571.102 Standard No. 102; Transmission shift position sequence, starter interlock, and transmission braking effect. § 571.103 Standard No. 103; Windshield defrosting and defogging systems. § 571.104 Standard No. 104; Windshield wiping and washing systems. § 571.105 Standard No. 105; Hydraulic and electric brake systems. § 571.106 Standard No. 106; Brake hoses. § 571.108 Standard No. 108; Lamps, reflective devices, and associated equipment. § 571.109 Standard No. 109; New pneumatic and certain specialty tires. § 571.111 Standard No. 111; Rear visibility. § 571.113 Standard No. 113; Hood latch system. § 571.116 Standard No. 116; Motor vehicle brake fluids. § 571.117 Standard No. 117; Retreaded pneumatic tires. § 571.118 Standard No. 118; Power-operated window, partition, and roof panel systems. § 571.119 Standard No. 119; New pneumatic tires for motor vehicles with a GVWR of more than 4,536 kg (10,000 lb.) and motorcycles. § 571.120 Tire selection and rims and motor home/recreation vehicle trailer load carrying capacity information for motor vehicles with a GVWR of more than 4,536 kg (10,000 lb.). § 571.121 Standard No. 121; Air brake systems. § 571.124 Standard No. 124; Accelerator control systems. § 571.125 Standard No. 125; Warning devices. § 571.131 Standard No. 131; School bus pedestrian safety devices. § 571.136 Standard No. 136; Electronic stability control systems for heavy vehicles. § 571.201 Standard No. 201; Occupant protection in interior impact. § 571.202 Standard No. 202; Head restraints; Applicable at the manufacturers option until September 1, 2009. § 571.202a Standard No. 202a; Head restraints; Mandatory applicability begins on September 1, 2009. § 571.203 Standard No. 203; Impact protection for the driver from the steering control system. § 571.204 Standard No. 204; Steering control rearward displacement. § 571.205 Standard No. 205, Glazing materials. § 571.206 Standard No. 206; Door locks and door retention components. § 571.207 Standard No. 207; Seating systems. § 571.208 Standard No. 208; Occupant crash protection. § 571.209 Standard No. 209; Seat belt assemblies.

3.2  Legal Framework Conditions

31

§ 571.210 Standard No. 210; Seat belt assembly anchorages. § 571.212 Standard No. 212; Windshield mounting. § 571.217 Standard No. 217; Bus emergency exits and window retention and release. § 571.219 Standard No. 219; Windshield zone intrusion. § 571.220 Standard No. 220; School bus rollover protection. § 571.221 Standard No. 221; School bus body joint strength. § 571.222 Standard No. 222; School bus passenger seating and crash protection. § 571.226 Standard No. 226; Ejection Mitigation. § 571.301 Standard No. 301; Fuel system integrity. § 571.302 Standard No. 302; Flammability of interior materials. § 571.303 Standard No. 303; Fuel system integrity of compressed natural gas vehicles. § 571.304 Standard No. 304; Compressed natural gas fuel container integrity. § 571.305 Standard No. 305; Electric-powered vehicles: electrolyte spillage and electrical shock protection. Be sure to look for additional regulations, as the regulations may change. All FMVSSs (and CMVSSs) are self certified. This means that a manufacturer validates certification and documents that every vehicle is compliant; but the manufacturer does not submit such certification to a government authority prior to introducing the product into commerce, as in type certification like with emissions regulations. Regulatory agencies may test a vehicle to determine if the vehicle truly complied with the regulations, and if the vehicle did not comply, the manufacturer could be forced to recall the vehicle and remedy the problem. Alternatively, regulatory agencies may demand from manufacturers records demonstrating that, at the time a vehicle was introduced into commerce, the manufacturer had certified it as compliant with adequate justification that the vehicle in fact complied. FMCSRs FMCSRs involve many of the same topics as FMVSSs, including lights, brakes, and safety systems. In some cases, the FMCSRs simply refer back to the FMVSSs. For example, in the case of lights and brakes, the FMCSRs state that an in-use vehicle must meet the FMVSS 108 and 121 standards, respectively, in force at the time the vehicle was built. Because those standards point back to the FMVSSs, vehicle owners who are responsible for the FMCSR compliance expect vehicle manufacturers to build compliant vehicles. Some FMCSRs relate to safety features that a customer may install on a vehicle or may buy with the new vehicle, for example, fuel tanks. When the vehicle manufacturer sells a vehicle with fuel tanks, those must comply with the drop test, the flame test, and so on that are in the FMCSR. If a vehicle owner replaces a fuel tank, then that replacement tank must comply with the same test requirements. Similarly, there is an FMCSR that prohibits a vehicle operator from installing components on certain areas of a windshield. When a manufacturer sells items for windshield, the manufacturer must design the components such that they do not violate the operator’s FMCSR obligation. Below is a list of some of the FMCSRs relevant to heavy-duty vehicles:

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§ 393.9 Lamps operable, prohibition of obstructions of lamps and reflectors. § 393.11 Lamps and reflective devices. § 393.13 Retroreflective sheeting and reflex reflectors, requirements for semitrailers and trailers manufactured before December 1, 1993. § 393.17 Lamps and reflectors - combinations in driveaway-towaway operation. § 393.19 Hazard warning signals. § 393.22 Combination of lighting devices and reflectors. § 393.23 Power supply for lamps. § 393.24 Requirements for head lamps, auxiliary driving lamps and front fog lamps. § 393.25 Requirements for lamps other than head lamps. § 393.26 Requirements for reflectors. § 393.28 Wiring systems. § 393.30 Battery installation. § 393.40 Required brake systems. § 393.41 Parking brake system. § 393.42 Brakes required on all wheels. § 393.43 Breakaway and emergency braking. § 393.44 Front brake lines, protection. § 393.45 Brake tubing and hoses; hose assemblies and end fittings. § 393.47 Brake actuators, slack adjusters, linings/pads and drums/rotors. § 393.48 Brakes to be operative. § 393.49 Control valves for brakes. § 393.50 Reservoirs required. § 393.51 Warning signals, air pressure and vacuum gauges. § 393.52 Brake performance. § 393.53 Automatic brake adjusters and brake adjustment indicators. § 393.55 Antilock brake systems. § 393.60 Glazing in specified openings. § 393.61 Truck and truck tractor window construction. § 393.62 Emergency exits for buses. § 393.65 All fuel systems. § 393.67 Liquid fuel tanks. § 393.68 Compressed natural gas fuel containers. § 393.69 Liquefied petroleum gas systems. § 393.70 Coupling devices and towing methods, except for driveaway-towaway operations. § 393.71 Coupling devices and towing methods, driveaway-towaway operations. § 393.75 Tires. § 393.76 Sleeper berths. § 393.77 Heaters. § 393.78 Windshield wiping and washing systems.

3.3  Vehicle Variants

33

§ 393.79 Windshield defrosting and defogging systems. § 393.80 Rear-vision mirrors. § 393.81 Horn. § 393.82 Speedometer. § 393.83 Exhaust systems. § 393.84 Floors. § 393.86 Rear impact guards and rear end protection. § 393.87 Warning flags on projecting loads. § 393.88 Television receivers. § 393.89 Buses, driveshaft protection. § 393.90 Buses, standee line or bar. § 393.91 Buses, aisle seats prohibited. § 393.93 Seats, seat belt assemblies, and seat belt assembly anchorages. § 393.94 Interior noise levels in power units. § 393.95 Emergency equipment on all power units. § 393.201 Frames. § 393.203 Cab and body components. § 393.205 Wheels. § 393.207 Suspension systems. § 393.209 Steering wheel systems. Bear in mind that this list may not be up to date, as regulations are subject to change. It is good practices to regularly check with the compliance department to obtain the latest version of regulations.

3.3 Vehicle Variants 3.3.1 Axle Formulas The axle formula describes how many axles the vehicle has and what functions the axles perform. The first digit in the axle formula indicates how many wheels or dual wheels the vehicle has. The second digit indicates how many of the wheels are driven. A slash is then followed by the number of steered wheels. A vehicle with wheel formula:

 8 × 4 4

(3.7)

has eight wheels or dual wheels, i.e., four axles. Of these, two axles are driven and two are steered. Letter combinations give additional information:

34

3  Entire Vehicle

4x2

6x2 VLA

4x4

6x4

6x2

6x6

steered

with dual wheels

unsteered

with single wheels

driven

not driven

8 x 4/6 ENA

6 x 2/2 DNA

8 x 2/4 ENA

6 x 2/4

8 x 2/6 ENA

8 x 6/4

6 x 2/4 NLA

8 x 4/4 ENA

8 x 8/4

8 x 4/4

Fig. 3.9   Examples of various axle configurations

• • • •

NLA described a trailing axle. DNA stands for a trailing axle with dual wheels. ENA stands for a trailing axle with single wheels. VLA is the leading axle.

Figure 3.9 shows various axle configurations. Other axle configurations are conceivable. A fifth axle, which are becoming more and more popular further increases the number of possible axle formulas.

3.3.2 Geometry of the Vehicle When defining the entire vehicle, the outer dimensions of the vehicle are important features. The boundary conditions, which must be complied with, are derived from the legal provisions set forth in Sect. 3.2.2.

35

3.4  Driving Resistance and Longitudinal Dynamics

Max. body length

Front overhang

Approach angle

Wheelbase

Ramp breakover angle

Rear overhang

Ground clearance

Departure angle

Overall length

Fig. 3.10   Angles of approach/departure and ramp breakover angle, shown here on a light truck with four-wheel drive. This illustration is based on [17]

However, there are a lot of other dimensions which differentiate the vehicles. These include, for example, the wheelbase, the distance between the rear axle and the ­fifth-wheel kingpin, the tire size and the frame track. Other typical dimensions which are of particular relevance for off-road vehicles are, for example, the overhang (front and rear), the angles of approach and departure, the ramp breakover angle and ground clearance. These are illustrated in Fig. 3.10.

3.4 Driving Resistance and Longitudinal Dynamics In this case longitudinal dynamics deals with how fast a vehicle can go, and how well it accelerates. Of course, the term longitudinal dynamics sounds much more fun than speed and acceleration, so we will continue to call it longitudinal dynamics. Longitudinal dynamics is the result of the interplay between driving resistance and the force that is available to overcome driving resistance. Driving resistance in turn is made up of air resistance, rolling resistance and grade resistance when the vehicle is climbing or descending a gradient. Ocassionally in literature, the force needed to accelerate the vehicle is considered as part of the driving resistance. This practice will not be adopted here, not least because, strictly speaking, it is incorrect.2

FDriving resistance−during−constant−travel = FAero + FRoll + FGrade

2Driving

resistance interferes with or changes the uniform, smooth movement of the vehicle.

(3.8)

36

3  Entire Vehicle

Fig. 3.11   The gravitational force FG and the gradient angle α together give the normal force FN. That is the force with which the vehicle is pressed down onto the road. In addition, the grade force FH is what propels the vehicle downhill

FH = FG • sin α α α FN = FG • cos α FG = m • g

Aerodynamic drag acts on a rolling vehicle as follows FAero:

FAero = 1/2 · ρ · v2 · A · cd

(3.9)

Where v is the speed, ρ is the density of the air and A · cd describes the shape of the vehicle. A is the leading surface of the vehicle, while the cd value describes the aerodynamic quality of the shape. A moving truck is also subject to rolling friction force FRoll:

FRoll = mTotal · g · cRoll · cos(α)

(3.10)

In this equation, the factor cos(α) takes into account the reduced normal force when the vehicle is driving up a gradient (see Fig. 3.11). When the vehicle is driving uphill, the grade force FGrade must be overcome:

FGrade = mTotal · g · sin(α)

(3.11)

These forces slow the vehicle down. In order to maintain speed, the drive unit of the vehicle must deliver an equivalent driving force. If the vehicle is to not only maintain constant speed but actually accelerate, an accelerating force must be calculated into this3:

FAcceleration = mTotal · a · fRot

(3.12)

fRot is a correction factor which takes into account the fact that an additional force is needed to overcome the moment of inertia of rotating masses (wheels, driveshaft, etc.). fRot is also called the allowance for rotating parts. Accordingly, the total force equation may be expressed as follows:

Ftotal = FAero + FRoll + FGrade + FAcceleration

(3.13)

The power input that is required to overcome driving resistance and accelerate the vehicle is calculated by:

3As

was mentioned earlier, we do not include this force with the driving resistance. We consider driving resistance to be only the force that acts against even motion.

37

3.4  Driving Resistance and Longitudinal Dynamics

PPower = FDriving resistance · v + FAcceleration · v = FAero · v + FRoll · v + FGrade · v + FAcceleration · v = 1/2 · ρ · v3 · A · cd

(3.14)

+ mTotal · g · cRoll · cos(α) · v + mTotal · g · sin(α) · v + mTotal · a · fRot · v

A reduction in driving resistance results in lower fuel consumption for the same driving. Of course, if the driving resistance is reduced, the additional power performance available can also be used to increase the performance. [18] shows both of these options for comparison. The energy that is used to overcome the aerodynamic drag and the rolling resistance must be considered as lost energy. On the other hand, the energy applied to overcoming the grade resistance (driving uphill) or used for accelerating is then stored in the vehicle as potential energy4 or kinetic energy5. This energy is expended in a coasting phase or dissipated by braking. A force counteracting the driving resistance must be available to propel the vehicle. If the force available from the drive unit is greater than the driving resistance, the vehicle will accelerate. Since the aerodynamic drag increases with speed, the driving resistance also increases with speed, and the vehicle will continue to move faster until the driving resistance and the driving force are in equilibrium again. The equilibrium state is characterized by the equation (quantitatively):

FPowertrain = FDriving resistance−at−Constant speed = FAerodynamic drag + FRolling resistance + FGrade

(3.15)

The driving power is calculated from the torque M at the drive wheel and the radius of the drive wheel:

FPowertrain =

MDrive axle rTires

(3.16)

The drive axle torque is in turn derived from the engine torque and the transmission ratios of the drivetrain, that is to say the gear ratio of the transmission and the axle gearing:

FPowertrain = MEngine · iGear · iAxle transmission ·

4Potential

1 rTires

(3.17)

energy is energy that is derived from the position of a body in a force field. For example, the positional energy of an elevated body. 5Kinetic energy is the energy of a body in motion.

38

3  Entire Vehicle 800

Engine power [hp]

pe

uro

700 600 500 400

ine

Ma

200

gine

en lling

se

Best

100

out

in s

tern

es t in w

u

outp

tio

duc

pro

u

xim

300

ng me

ed

fer

of put

s erie

E n in

pean

Euro

nce

ista ng-d

lo

ge

haula

2015

2005

1995

1985

1975

1965

1955

0

Year

Fig. 3.12   Trend in engine power in Europe. The maximum available engine power in series-manufactured trucks increases by an average of 10 hp per year. The engine power requested most often by longdistance haulage customers increases on average by about six hp per year

The power input is calculated as:

PPowertrain = FPowertrain · v

(3.18)

In 2014, engines generating around 450 hp were used in standard long-distance hauling trucks in order to offer appropriate driving performance. More powerful engine outputs are available. Figure 3.12 shows the evolution of engine power in trucks over the last 50 years. The power of the most common engines (fleet vehicles, etc.) increased by an average of about six hp per year. The maximum power of the most powerful engines offered in series-produced vehicles increased by about 10 hp per year. The various symbols in Fig. 3.12 stand for different vehicle manufacturers. It is noticeable that several manufacturers compete for the crown in producing the most powerful engine.

3.5 Lateral Dynamics Lateral dynamics is concerned with how a vehicle behaves in bends. By virtue of their design, this is not a strong point for trucks, and the driver is always well advised to approach bends with caution. The tilt threshold of a loaded truck with a relatively low center of gravity is reached with a lateral acceleration in the order of about 0.7 g, i.e. 0.7 times normal g­ -force.6 6Acceleration

due to gravity is denoted by the letter g and is equivalent to about g = 9.81  m/s2.

3.5  Lateral Dynamics

39

Maximum lateral acceleration [g]

Fig. 3.13   Maximum possible lateral acceleration as a function of the center of gravity, according to Eq. 3.22

1,00

0,80

0,60

0,40 1,5

1,8

2,1

2,4

2,7

Height of center of gravity [m]

If the center of gravity of the load is high, the possible lateral acceleration is lower. Figure 3.13 shows qualitatively how the maximum possible lateral acceleration changes as a function of the center of gravity. Figure 3.14 shows the geometric relationships. If the vehicle is considered as an idealized rigid body, the forces act on the center of gravity of the vehicle. The resulting force FR consisting of centrifugal force FZ and gravity force FG must be within the tire contact patch of the vehicle. The outermost point of this tire contact patch is essentially the corner point of the tire. The borderline case is reached when the resulting force FR just passes through this point: (3.19)

FZ < FG · tan α

a

b

c

d

Width w 2.55 m Borderline case Center of gravity

Vehicle tilts

Fz

b/2

FG

h α

threshold

FR

Fig. 3.14   Simple parallelogram of forces to estimate a vehicle’s tilt threshold

Low center of gravity

40

3  Entire Vehicle

For angle α (see Fig. 3.14 a):

tan α =

=

b/2 h

b 2·h

(3.20)

(3.21)

With FZ m  · alateral and FG = m  · g, the following applies approximately as the condition for tilt stability:

alateral < g ·

b 2·h

(3.22)

This estimation of the tilt threshold does not take certain effects into account: In this case the vehicle is treated as a rigid body and deformations are ignored. In real-life situations, the vehicle leans; the tires and frame bend, and the ­asymmetrically-acting forces cause one side of the vehicle to bear down on the suspension. The body and frame also move towards each other, within certain limits. These effects cause the center of gravity to shift outwards and reduce the possible lateral acceleration. The tilt threshold can be lowered particularly severely by a shifting load. For example, liquids may swish back and forth or hanging pig carcasses may swing outwards and seriously impact the vehicle’s stability. A further effect which is not considered here is that the vehicle may skid sideways. This at least temporarily reduces the danger of tilting. The side-slip angle is described as how much the vehicle’s current direction of motion deviates from the vehicle’s longitudinal axis. When the side-slip angle is clearly visible or felt unmistakably, the vehicle is said to be drifting.

3.6 Weight of the Entire Vehicle The motor carrier needs to know the curb weight of a vehicle for certain transport tasks. Since the statutory gross weight of the vehicle and the axle loads must be complied with (see Sect. 3.2.2), the unladen weight of the vehicle is critical for determining the payload the vehicle can carry when transporting heavy goods. “Tank-silo” forwarders are a typical example of these. These are haulage companies which transport liquids such as mineral oil, chemicals or food (milk, red wine) in tanker trucks. Tanker trailers often have a volume of over 30,000 l. But since the dead weight of a tractor unit can easily amount to 14 t, the tank can only be loaded with 26 t (here we consider a 40 t weight limit), even though – depending on the liquid in question – there might still be plenty of room in the tank. If the curb weight of the vehicle can be lowered, the company’s productivity increases.

3.7 Comfort

41

3.7 Comfort Comfort is a big subject. From comfort in operation of the vehicle (maintenance, driveaway control) to sleeping. Many aspects of comfort are essentially determined by the cockpit and are therefore explained in the context of the cab (see [5]). But some comfort requirements can only be met by optimizing the entire vehicle.

3.7.1 Ride Comfort Suspension is important for ride comfort. All the ups and downs of the road are dependably communicated to the load via the path: Tires – Axle – Frame – Body, and to the driver via the path: Tires – Axle – Frame – Cab – Seat. Both vertical and horizontal impacts are transmitted. In order to protect the load and lighten the burden on the driver, the bumps are attenuated by components that soften and absorb them. The primary suspension system is the chassis suspension. This consists of the bouncy tires and the actual suspension assembly in the axle support. Steel and air springs are used. This primary axle suspension system must be able to support a very wide weight range, because the axle load on a fully loaded truck can be as much as ten times more than on an unloaded vehicle. The secondary suspension system consists of the suspension elements in the cab. The cab mounting and the spring behavior of the seat. The entire suspension system, from the unevenness in the road to the driver, is illustrated schematically in Fig. 3.15. To achieve optimum driver comfort, all the spring and damping elements in the system must be tuned to work together.

Fig. 3.15   Elastic components which help to enhance suspension comfort for the driver. To deliver optimum suspension comfort, the individual suspension elements must be designed to work together

Seat bolster Suspension seat Cab mounting Axle suspension

Tires

Comprehension Questions

The comprehension questions serve to test how much the reader has learned. The answers to the questions can be found in the section to which the respective question refers. If you have difficulty answering the questions, we recommend that you reread the relevant section. A.1 Costs (a) What costs are involved in the operation of a truck? (b) What influences can change these costs? A.2 Coordinate system (a) How is the coordinate system normally determined? In what direction do the x- and y-axes point? (b) What are yaw, roll and pitch? A.3 Wheel configuration (a) What does the wheel configuration describe? (b) What is a 6 × 4/2? A.4 Dimensions (a) What is the maximum permissible length for a tractor semitrailer combination and a double trailer combination in the US? (b) Why are (nearly) all trucks in the US conventional vehicles? (c) Why do cab-over-engine vehicles exist in other countries?

© Springer-Verlag GmbH Germany, part of Springer Nature 2021 M. Hilgers and W. Achenbach, Entire Vehicle, Commercial Vehicle Technology, https://doi.org/10.1007/978-3-662-60766-4

43

44

A.5 Vehicle combinations What are the most widespread vehicle combinations? A.6 Terminology Explain the following terms: (a) Wheelbase, (b) Ramp breakover angle, and (c) Longitudinal dynamics.

Comprehension Questions

Abbreviations and Symbols

The following is a list of the abbreviations used in this booklet. The letters assigned to the physical variables are consistent with common usage in engineering and natural sciences. The same letter can have different meanings depending on context. For example, lower case c is a very busy letter. Some abbreviations and symbols have been subscripted to avoid confusion and improve the readability of formulas, etc.

Lowercase Latin letters a acceleration b length, often width c coefficient, proportionality constant cd coefficient of drag (Aerodynamics) f coefficient or correction factor fRot additional load factor in rotary motion g normal g force (g = 9.81 m/s2) g gram, unit of mass h length, often height h hour, unit of time hp horsepower, unit of power (not an SI unit) – 1 hp = 735.5 W i gear ratio, ratio of rotating speeds k kilo  = 103 = multiplication factor of 1000 kg kilogram, unit of mass km kilometer, unit of distance – 1 km = 1000 m km/h kilometers per hour, unit of speed – 100 km/h = 27.78 m/s kW kilowatt, unit of power – 1 kW = 1000 Watt kWh kilowatt hour, unit of energy l length l liter, unit of volume – 1 l = 10−3 m3 © Springer-Verlag GmbH Germany, part of Springer Nature 2021 M. Hilgers and W. Achenbach, Entire Vehicle, Commercial Vehicle Technology, https://doi.org/10.1007/978-3-662-60766-4

45

46

Abbreviations and Symbols

lb pounds, unit of mass (not an SI unit) m mass m meter, unit of length m milli  = 10−3 = a thousandth part mph miles per hour, unit of speed (not an SI unit) – 100 mph = 44.70 m/s p pressure r length, often radius rpm revolutions per minute; angular speed s length (distance) t time t ton, unit of mass – 1 t = 1000 kg v speed x typical designator for one of the spatial coordinate axes y typical designator for one of the spatial coordinate axes z typical designator for one of the spatial coordinate axes

Uppercase Latin letters A area, particularly face area CARB california Air Resources Board CO carbon monoxide CO2 carbon dioxide DAS driver Assistance System DNA trailing axle with dual wheels DPF diesel particulate filter E energy ECCC environment and Climate Change Canada, Canadian Standard ECE economic Commission for Europe of the United Nations EEV enhanced Environmentally Friendly Vehicle – European emission standard for buses and trucks (stricter than EURO V) ELR european Load Response Test – Test procedure for emissions legislation ENA trailing axle with single wheels EPA environmental Protection Agency, US government agency ESC european Stationary Cycle – Test procedure for emissions legislation ETC european Transient Cycle – Test procedure for emissions legislation F force FG gravitational force FZ centrifugal force FMCSR federal Motor Carrier Safety Regulations (US)

Abbreviations and Symbols

47

FMVSS federal Motor Vehicle Safety Standard (US) GHG greenhouse gases GPS global Positioning System GWP global Warming Potential HC hydrocarbons J joule, unit of energy K kelvin, unit of temperature on the Kelvin scale M torque, turning moment M mega  = 106 = Multiplication factor of one million MJ megajoule, unit of energy – One million Joules MW megawatt, unit of power – One million Watts N newton, unit of force – 1 N = 1 kgs2m NH ammonia N2O nitrous oxide, laughing gas NOx nitrogen oxide NLA trailing axle NMHC non-methane hydrocarbons OBD on-board diagnosis OEM original Equipment Manufacturer P power, output PM particulate matter StVZO  straßenverkehrszulassungsordnung (German Road Vehicle Registration Regulation) T temperature (in Kelvin or °C) TCO total cost of ownership (costs incurred over the useful life of the vehicle or other asset) TÜV  technischer Überwachungsverein (German technical inspection association) V volume V volt, unit of electrical voltage VLA leading axle W mechanical work or mechanical energy Wkin kinetic energy Wpot potential energy W watt, unit of output Wh watt hour, unit of energy – cf. the more common kWh WHSC world Harmonized Stationary Cycle – Test procedure for emissions legislation, supersedes ESC WHTC world Harmonized Transient Cycle – Test procedure for emissions legislation, supersedes ETC

48

Abbreviations and Symbols

Lowercase Greek letters α angle β angle γ angle μ Friction value, sometimes also µk Coefficient of friction μ stands for micro = 10−6 = a thousandth part ρ Density φ angle

References

General books on automotive engineering 1. Robert Bosch GmbH (pub.): Kraftfahrtechnisches Taschenbuch, 28th edn. Springer Vieweg, Wiesbaden (2014) 2. Braess, H., Seiffert, U. (pub.): Handbuch Kraftfahrzeugtechnik, 7th edn. Springer Vieweg, Wiesbaden (2013) 3. Hoepke, E., Breuer, S. (pub.): Nutzfahrzeugtechnik. 7th edition, Springer Vieweg, Wiesbaden (2013) 4. Hilgers, M.: Fuel Consumption and Consumption Optimization. Commercial Vehicle Technology. Springer, Berlin/Heidelberg/New York (2021) 5. Hilgers, M.: The Driver’s Cab. Commercial Vehicle Technology. Springer, Berlin/Heidelberg/ New York (2021) 6. Hilgers, M.: Vocational Vehicles and Applications. Commercial Vehicle Technology. Springer, Berlin/Heidelberg/New York (2021)

Technical articles 7. Truck Tonnage Index, American Trucking Association (2017) 8. Kaiserliches Patentamt (Imperial Patent Office) Berlin: Patentschrift No. 37435, Fahrzeug mit Gasmotorenbetrieb, granted to Benz & Co in Mannheim (1886) 9. Sievers, I.: 110 Jahre Daimler-Lastwagen. Automobiltechnische Zeitschrift (ATZ) 09/2006 (2006) 10. An Analysis of the Operational Costs of Trucking, ATRI (2018) 11. ZF Friedrichshafen et al.: ZF-Zukunftsstudie Fernfahrer, der Mensch im Transport-und Logistikmarkt (2012). http://www.zf-zukunftstudie.de. Accessed 2012 12. ECE Directives Webpages of the German Federal Ministry for Traffic, Construction and Urban Development. A to Z ! ECE Directives. http://www.bmvbs.de/Verkehr/Strasse/KfZtechnische-Vorschriften-,1446.1032708/ECE-Regelungen.htm 13. Exhaust emission standard for trucks and buses. Table for download on the website of the German Federal Environmental Agency – Version of January 2013. http://www.umweltbundesamt.de 14. Neumann, C., Wüst, K. et al.: Simulation-based homologation of truck ESC systems. 21st Aachen Colloquium Automobile and Engine Technology 2012 (2012) © Springer-Verlag GmbH Germany, part of Springer Nature 2021 M. Hilgers and W. Achenbach, Entire Vehicle, Commercial Vehicle Technology, https://doi.org/10.1007/978-3-662-60766-4

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50

References

15. Edlund, S., Fryk, P.-O.: The right truck for the job with global truck application desription. SAE Paper 2004-01-2645 (2004) 16. Soller, G.: Achslastprobleme abgeblasen! Verkehrsrundschau 3/2009, 54 (2009) 17. Daimler AG, FUSO: Canter. Der Nutzlaster. Product brochure – Version of September 2013 (2013). http://www.fuso-trucks.de. Accessed May 2014 18. Porth, D., Krämer, W.: Einsatz des Fahrleistungsgewinnes durch verbesserte Aerodynamik zur Fahrleistungssteigerung oder zur Verbrauchsminimierung. Automobiltechnische Zeitschrift (ATZ) 5/1993 (1993)

Index

A Aerodynamic drag, 36, 37 Allowance for rotating parts, 36 Angles of approach/departure, 35 Automobile, 3 Axle formula, 33

C Cab-behind-engine, 26 Cab-over-engine, 17, 26 Cd value, 36 Center of gravity, 38 Comfort, 41 Coordinate system, 4 Customer purchasing criteria, 15

D Daimler-Motoren-Gesellschaft, 1, 3 Depreciation, 10 Dimensions, 34 Distance between rear axle and fifth wheel kingpin, 35 Distance between the rear axle and the kingpin, 27 Driving power, 37 Driving resistance, 35

E Energy kinetic, 37 potential, 37 Engine power, 38

Entire vehicle, 17

F Frame track, 35 Front-to-rear installation, 18 Fuel consumption, 13

G Gear ratio, 37 Grade force, 36 Ground clearance, 35

L Ladder-type frame, 18 Lateral dynamics, 38 Leading axle, 34 Longitudinal dynamics, 35

M Maintenance, 12 Motor vehicle, 3

O Overhang, 35

P Paired transportation, 9 Pitch, 5 Power input, 38

© Springer-Verlag GmbH Germany, part of Springer Nature 2021 M. Hilgers and W. Achenbach, Entire Vehicle, Commercial Vehicle Technology, https://doi.org/10.1007/978-3-662-60766-4

51

52 Profitability, 9

Q Quality, aerodynamic, 36

R Ramp breakover angle, 35 Repairs, 12 Ride comfort, 41 Road use charge, 14 Roll, 5 Rolling friction force, 36 Rolling resistance, 35

Index Tilt stability, 40 Tilt threshold, 38 Tire size, 35 Toll, 14 Trailer, 4 Trailing axle, 34 with dual wheels, 34 with single wheels, 34 Trend in engine power, 38

U Unladen weight, 40

V Vehicle concept, 17 S Semitrailer, 3 Semitrailer tractor, 19 Service contract, 12 Suspension, 41

T the transport task, 8

W Wheelbase, 35

Y Yaw, 5