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The fuel cell bus program at Georgetown University (GU) has directed the operational development and testing of three hybrid fuel cell powered buses for transit operation. These are the world's first liquid-fueled, fuel cell powered road vehicles. This paper describes the emissions testing of one of these buses on a heavy duty chassis dynamometer at West Virginia University (WVU). The tested bus was driven by a 120 kW DC motor and utilized a 50 kW phosphoric acid fuel cell (PAFC) as an energy source with a 100 kW battery for supplemental power. A methanol/water fuel mixture was converted by a steam reformer to a hydrogen rich gas mixture for use in a fuel cell stack. Emissions from the reformer, fuel cell stack and startup burner were monitored for both transient and steady-state operation.

This paper discusses controller development for an active, off-road vehicle suspension system. A brief review of electronic filters and their characteristics is used to provide insight on the difficulties of designing a control algorithm for negotiating hilly and rough terrain at higher speeds. Two controller designs are presented. One was designed by pole placement and causes the suspension response to approximate a Type 1 Chebychev filter. The other was designed using constrained optimization. A comparison and discussion of simulation results leads to the conclusion that the suspension should be adaptively or predictively controlled for arbitrary terrain and velocity conditions.

In this study, a series of tests have been carried out to evaluate the effects of the injection rate and timing on bsfc, NOx, and PM emissions in a heavy-duty diesel engine with TICS FIE system. Injection line pressure, cylinder pressure, NOx and smoke were measured with various injection times and injection rates. The injection rate was altered at a fixed injection timing, which could be realized either by changing the TICS setting time or by using different cam profiles. The injection time was varied by using TICS timing control function at a given setting time. A parametric study of the injection rate in in-line pump system was tried to correlate injection rate variations with combustion characteristics and emission. Two parameters, the injection pressure rising rate and the initially injected fuel quantity were introduced to characterize fuel injection.

Effects of fuel properties, in terms of the 90% boiling point (T90) and the polycyclic aromatic hydrocarbon (PAH) content, as well as oxidation catalysts on diesel exhaust emissions have been examined using three direct injection (DI) diesel engines and two diesel passenger cars equipped with oxidation catalysts. The diesel emission tests using two series of test fuels, one for examining the effects of the T90 and another for polycyclic aromatic hydrocarbons, have indicated that total hydrocarbons (THC) and particulate matter (PM) decrease as the T90 is reduced. PM and THC were also found to be on a declining trend with a decreasing content of polycyclic aromatic hydrocarbons. The extent of these effects of fuel properties on exhaust emissions varied with engine and car models, and appeared to be smaller in engines or cars having lower exhaust emissions.

A new 12.5 L four-valve heavy duty diesel engine has demonstrated that Powdered Metal (PM) is an effective material alternative to wrought steel for the valve bridge. The valve bridge, an element that spans the pair of intake or exhaust valves, allows a single rocker arm to actuate the pair of valves. The component is subjected to a high number of cycles at a moderately high load and geometry precision is essential for desirable wear characteristics. The PM material selected, MPIF FL4605-120HT, has replaced 8620 steel after making component geometry changes. The PM part has a higher load capacity than the original design with equivalent wear characteristics and offers a 80% cost saving over the original design. This paper presents the geometry changes defined by FEA analysis and component testing performed to verify the change from wrought steel to PM. A required characteristic of this component is moderately high fatigue strength.

In the case of turbocharged heavy duty diesel engines, the total efficiency of the turbocharger is higher than for smaller turbos for passenger cars. It is difficult to recirculate exhaust gas because of higher intake manifold pressure in comparison to exhaust gas pressure. IHI has developed a new turbocharger for exhaust gas recirculation for heavy duty diesel engines. It has a recirculation port at compressor side. The port is connected with a narrow annular slit located at the diffuser inlet, where the static pressure is lower than intake manifold. The result of JIS diesel 13 mode test with this turbocharger showed 26 % lower NOx without significant penalty of fuel consumption.

The time and the distance traveled during the acceleration and the velocity retaking are parameters used for the comparison and the project of vehicles. In this paper equations for the calculation of those parameters are presented. Several criteria are presented for the shift gears. It is also verified the occurrence or not of total slip during the acceleration of the vehicle. The theoretical models were implemented in a developed computational system. Such system was applied in a Mercedes-Benz do Brazil sample vehicle, in order to facilitate comparisons between the simulate values and the experimental road tests.

In late 1996, Daimler-Benz together with WABCO and Scania together with Bosch presented the first electronically controlled brake systems (EBS) in their towing vehicles. Since then roughly 2000 ACTROS per month have been produced with EBS. Other vehicle manufacturers will introduce EBS in the near future [5]. The technical advantages of EBS combined with the increased application of disc brakes, are: improved safety through shortened stopping distance better vehicle stability and brake comfort optimized brake monitoring and higher profitability However, with this first step the technical possibilities are limited to towing vehicles combined with conventionally braked trailers. The overall braking performance of the combination unit can be further improved when the trailers are equipped with an electronically controlled brake system.

This paper presents the Vehicle Dynamics Control (VDC) for commercial vehicles developed by BOSCH. The underlying physical concept is discussed in the second section after a short introduction. The third section shows the computer simulation used in the development process. Section four describes the controller structure of the VDC system. In Section five the use and effectiveness of VDC for commercial vehicles is shown in different critical driving situations. This is done by using measured data collected during testing (lane change, circular track) and it demonstrates that the safety improvements achieved for passenger cars are also possible for commercial vehicles.

The European automotive EMC directive, 95/54/EC, provides the EMC approval regime for motor vehicles of 4 wheels or more and all equipment intended for fitment to them. The EMC Chapter of the European multi-directive for 2/3 wheeled vehicles, 97/24/EC, provides the approval regime for these vehicles and their equipment. Regulation 10 of the United Nations Economic Commission for Europe (ECE) is being updated to provide similar EMC requirements. ISO draft standards are available for forestry and agricultural tractors, and for earth-moving machinery. This paper explains the relationship of these different approvals to the general EMC directive, 89/336/EEC, and offers interpretations for vehicles and their components as well as the implications for the various types of aftermarket components.

Transmission shift lever jumpout is a truck system dynamics problem that is caused by engine/transmission pitching in response to rough road input. Severe rotational motion imposes inertial forces on the shift lever system, potentially causing the shift rail to move to neutral. Dynamic testing and analysis has led to suggestions for system design improvement including lever geometry optimization and engine mount stiffness and damping improvement. A counterweight addition to the lever system will also stabilize the dynamics.

Tests of class 2,3,and 5 straight trucks were made to determine the affect of aftermarket aerodynamic aids on fuel economy and handling. It was determined that the potential exists for significant improvement in the fuel efficiency of these classes of trucks.

Allison Transmission has developed a family of two new automatic transmission products, the 1000 Series and the 2000 Series, for the light and medium duty commercial markets. This technical paper will introduce these products by reviewing the early development efforts which helped define the transmission attributes that they should bring to market. This included the analysis of Allison's product portfolio and industry rating requirement trends, and the extensive market research which identified the key product attributes and led to the concept selection. There is also a review of the 1000 Series and 2000 Series product features as well as a discussion on the development of their respective vocational ratings. Future papers will provide greater detail on the various technical aspects of this new product family's design.

Based on analysis problems of vehicle with present automatic transmission, an Intelligent Shift Strategy(ITSS) is proposed for the first time. Three kinds of information, which are the driver intention, the vehicle dynamic characteristics and the outside environment, are included in it, and the humachine technology is applied to decide shift strategy.

The active safety of tractor / trailer-combinations plays an important role in regard to traffic safety in general. For improving the active safety of tractor / trailer-combinations, it is necessary to investigate the interactions between the towing vehicle and the trailer during braking maneuvers. This paper describes the ECE-regulations for the braking force distributions of tractor/full trailer- and tractor / semitrailer-combinations. The influence of different layouts of the braking systems within these regulations on the coupling forces between tractor and trailer and the driving performance of the units during braking is investigated. The dynamical behaviour of a tractor/full-trailer-combination and a tractor / semitrailer-combination are both discussed with the aid of simulations of the ISO-standard testing procedures “Braking in a turn” and “Braking straight ahead”.

Difficulty of the Automatic Transmission(AT) is to properly control its clutch while the vehicle starts. An intelligent hierarchical controller is proposed in this paper. The upper of it is an intelligent PID controller based on a driver's experience and an expert's knowledge. It gives real time signals to the lower controller and coordinates the control between engine and clutch. The lower Variable Structure Fuzzy Controller (VSFC) executes the upper controller's direction signal.

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.