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The cruise control as one of promising vehicle active control has been receiving a considerable attention in recent years, so the related problems are discussed in this paper. Mathematical model of the engine under the steady state and general dynamics equation of the Continuously Variable Transmission(CVT) are given, the regulating principle of the operating state of the engine is analyzed, and the conjugate gradient method employed to solve the optimal control problem of the vehicle in the cruise control is described, so the operating state of the engine could be controlled. At end of paper, some results are provided to verify the approach based on the vehicular powertrain with a hydromechanical CVT.

A major co-operative international research program known as DIVINE (Dynamic Interaction between Vehicles and Infrastructure Experiment) has been completed by the Organisation for Economic Cooperation and Development OECD). DIVINE involved seventeen OECD member countries, and included specialists in vehicles, pavements, bridges, road management and transport policy. Inter-linked research projects were carried out in nine countries and the project took almost four years to complete. DIVINE set out to investigate the benefits of “road-friendly” suspensions for reducing pavement wear and to develop better means of assessing vehicle suspensions for road-friendliness. This paper summarises the most important results of DIVINE and presents means of assessing and simulating the road-friendliness of truck suspensions. Dynamic loading depends on the vehicle suspension, and the use of air suspension generally reduces dynamic loading.

A new oval test track will be designed, constructed and operated in a manner that will successfully pull-together representatives from virtually all of the key interests in dealing with the challenging issues of highway pavement and truck durability. With construction scheduled to begin in the Summer of 1998 and completion scheduled for late 1998 or early 1999, the mission and commitment for this venture is to pull-together the people from several state DOTs, respective universities, and, of vital importance, the truck manufacturing industry. Results from these tests, over a period of a few years, will provide answers that not only greatly improve performance of hot mix asphalt pavements in all state DOTs, but also efficiently and productively address issues of durability and wear performance of medium / heavy duty trucks and key components.

This study revisits pavement roughness and examines the suitability of the International Roughness Index (IRI) to describe passenger car ride quality, as well as heavy vehicle excitation and dynamic loads. It describes the development of a new pavement roughness index, called RIDE (Roughness Index for Driving Expenditure). RIDE is based on sprung mass acceleration, rather than relative axle displacement like the IRI. RlDE is calculated in the frequency domain on the basis of the transfer function of a reference vehicle. It results in the root-mean-square (RMS) acceleration of the sprung mass per unit length of pavement traveled. This index is compatible to the current ISO and it is also related to heavy vehicle dynamic excitation.

The development of larger more productive innovative heavy vehicle combinations for public road operations relies heavily on proving new vehicle concepts to both government and local authorities. In a number of cases simulation modelling has proved to be a useful tool in showing that proposed innovative heavy vehicle concepts are safer and more efficient alternative to conventional equipment. This paper provides examples of the use of AUTOSIM™ in developing custom yaw/roll and yaw/roll/pitch models for investigating the dynamic performance of combination vehicles. Models are described for large innovative road trains which incorporate B-doubles units. Consideration is given to the modeling of the trailing fidelity of these vehicles on non-planar surfaces and examples of model outputs for combination vehicles operating on various three-dimensional features are presented.

There are many ways to analytically represent a hydraulic powertrain mount. The application of the model significantly affects the type of model that should be used. An effective mass model can accurately represent hydraulic powertrain mount component level characteristics but a balanced force model is needed when the hydraulic powertrain mount is a component in a larger systems model. There are two types of hydraulic powertrain mounts that are widely used, inertia dominant and viscous dominant. Hydraulic powertrain mounts can be configured with a decoupler which can function as a small amplitude disconnect for idle isolation, affect the high frequency dynamic stiffness, and also affect the large amplitude ride frequency response.

The variation in the decoupling effect of exhaust flexible couplings under a vertical preload caused by changes in the direction of the exhaust pipe routing was investigated. Both self-supporting and underbody flexible couplings were tested. The results indicate that, in general, a preload decreases the decoupling efficiency of both types of flexible couplings. In addition, the results indicate that the efficiency of the flexible coupling is effected by the following three conditions: the direction of preload with respect to gravity, the location of the preload relative to the coupling, and the stiffness of the various components of the flexible coupling.

Many design philosophies have been used to design engine mount systems. One is to place the stiffness roll axis coincidental to the torque axis (crankshaft), to produce pure roll under static torque. Another is to focus the mount system to align with the inertial roll axis and uncouple dynamic roll. Recent trends have been to abandon mount system focusing as a criterion, in favor of controlling the six natural frequencies of the powertrain on the mount system. This paper discusses a technique to focus the mounts to uncouple the dynamic matrix, as much as possible within design constraints, while also maintaining control of the powertrain rigid body natural frequencies. Using engine mount system focusing to uncouple the dynamic matrix reduced lateral shake in an experimental vehicle. This reduction in vehicle shake was substantiated by total vehicle system models, experimental measurement, and subjective evaluation.

The laboratory tests used to define API GL5 have been the cornerstone of gear oil development for well over thirty years. In that time they have served the market very well. Lubricants developed with these test methods have provided adequate protection of axle components from severe wear, scuffing, corrosion, and oxidation. Recently, however, there has been an increasing trend toward extended drain intervals which changes the picture. Coupled with longer oil drain intervals there is a continuing increase of power throughput in the equipment. The combination of increased power and extended service life places significant stress on the oil such that the load carrying ability and thermal and oxidative stability could be greatly diminished under these conditions. During the past ten years the industry has been actively working toward a new gear oil specification that will address the performance needs of today's vehicles.

Navistar International has developed and launched a new model for local and regional vocations, meeting customer expectations while reducing complexity. This was accomplished by listening to customers and delivering a product in a short period of time. This vocationally focused vehicle proves that features associated with a line haul premium conventional can be incorporated in a value driven local / regional day cab tractor. The swift time to market was brought about by a developing climate for performance that includes living values which support success.

Austempered ductile iron (ADI) is a material having excellent mechanical properties and damping capacity. However practical mass production of ADI gears has not been possible due to ADI's poor machinability and distortion during the austempering heat treatment. With a new process method of carrying out hobbing before austempering when the material is in its soft condition, then austempering it and lastly, conducting the shave finishing process, we have diminished the above defects and developed practical ADI gears. These new gears generate less noise than ordinary nitrocarburized steel gears and are superior in pitting resistance.

Technologies and incremental costs for meeting the proposed 2004 US emissions standards for heavy-duty diesel engines are discussed in this paper. Manufacturers will most likely use a combination of technologies including reoptimized combustion chambers, fuel systems, air handling systems, electronic controls and aftertreatment. First year production incremental costs are estimated to range from between $257 and $467 to meet the new standards.

Road unevenness induces longitudinal as well as vertical forces in the suspension. The variation of vertical and longitudinal wheel forces can be of the same magnitude. Much work on vertical loads has been accomplished in heavy vehicle development, but less on longitudinal forces. Wheel forces have been measured on a semi-trailer tractor driven over a test track obstacle. The consistency of test results inspires confidence in the measured loads. Measured forces are compared with results from a simple simulation model. The influence of road-induced longitudinal forces on ride and chassis loads is demonstrated through simulations. The importance of longitudinal suspension compliance is discussed.

Meritor Heavy Vehicle Systems in conjunction with Detroit Diesel Corporation has developed an advanced patented shift system. The system monitors input and output speeds of the transmission, the neutral position of the shift lever, and the position of a ‘shift intent’ switch on the shift knob. The electronic controller processes this information and adjusts engine torque and speed to effect a shift of the manual transmission. This feature significantly reduces the driver workload while shifting.

Eaton has been working on technologies for cost effective, reliable and safe Automated Mechanical Transmissions (AMTs) since the mid 1970's. The company has introduced three different systems since the late 1980's, but all three systems were constrained by the lack of precise engine speed control during shifting. With the advent of electronic engine controls the constraint has been removed and precise engine speed control during shifting can be easily accomplished. The result is a simplified system that is powerfully intelligent and fully capable of automatic shifting i.e., the transmission system determines when to shift and executes the shift without any driver inducement across the broad spectrum of truck usage. This paper discusses some of the AMTs available to the truck market, showing how the system benefits both the OEM and the end user.

Basic lead-acid battery technology has remained virtually unchanged for almost 100 years. Although improvements have been made in chemistry and construction, the common causes that promote battery failure have remained the same. These causes are the result of sulfation buildup (crystallized sulfur molecules) on the battery plates. The most effective solution to this problem is pulse technology. Pulse technology helps eliminate battery failure by maintaining a higher active material processing area while creating a more consistent charge acceptance environment within the battery. As a result, productivity is improved, replacement and other battery-related expenses are avoided, and unnecessary negative environmental impact is averted.

An innovative Power Line Carrier (PLC) Communication system for video and digitally signal processed data distribution using the existing DC copper wire is presented. The major contribution consists of a new signal coupler that achieves a stable transmission bandwidth on the DC electrical lines. Several weeks of continuous beta tests achieved video transmission on the trucks +12V wiring (from the back of the truck to the driver's cabinet) and product manufacturing and delivery has started. Benefits include: simplicity of application; ease of implementation; effectiveness with video and data; applicability to all application types; elimination of coax and twisted pair wiring and its maintenance.

Use of power line technology is desirable for communication on vehicles, since it allows communication without adding wiring complexity beyond that provided by the electrical system, and furthermore allows easy retrofits. In some cases, mixed media systems may be optimal.

Multiplexed buses are necessary to add new electronic control systems on-board vehicles. With roughly 50% of these systems expected to be installed or modified after the vehicle rolls off the assembly line, plug-and-play retrofits are important. Using a network protocol that runs on the electrical wiring in a vehicle reduces wiring for new vehicles. In allowing use of wiring already installed on the vehicle, such a scheme also pays excellent dividends for retrofits. Over the life of a vehicle, networked electronic devices and sub-systems will be obtained from several different suppliers. Standard device profiles and a common network operating system are essential for their easy integration, whether on the assembly line or in the aftermarket.

A technique to compute vehicle weight (GVW or GCW) solely from measurements of force and acceleration taken onboard the tractor is described. A means to measure both variables by a single inexpensive sensor is disclosed, and algorithms are presented. Methods to compensate for real-world variables such as wind and grade are discussed, as are results obtained during 20,000 Km of testing. A potential means to determine GCW onboard the tractor without any additional hardware is presented. Applications, including ITS, are discussed, as are methods for instantaneous calibration.