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Malleable and ductile cast irons are used extensively in gearing and high strength applications within automotive power train applications. Advantages of malleable and ductile cast irons are low material cost with mechanical properties that meet or exceed the requirements of the intended application(s). One disadvantage of the malleable cast iron is the extensive heat treating required to obtain the proper microstructure and mechanical properties. Both malleable and ductile iron components require extensive machining to produce the finished component. The combination of heat treating and extensive machining often results in a component that is costly to manufacture. Recent advances in the Powder Metallurgy (P/M) process including high strength material systems and high density processing have achieved mechanical properties that meet or exceed the level achieved with the current malleable and ductile cast iron materials.

Recent demands within the automotive industry have been for applications requiring high hardness, high hardenability, and increased mechanical performance. These often conflicting requirements necessitated the development of new materials that offer high as-sintered hardness and good static/dynamic mechanical properties without the added expense of a secondary heat treatment. Traditionally, sinter-hardening materials have offered acceptable hardness but at the expense of mechanical properties and sintered density. This paper will document a series of sinter hardening materials that offer good compressibility, high hardness and enhanced mechanical properties. The discussion will focus on utilization of these materials in automotive applications (within both the engine and transmission) such as gears, cams and sprockets that are currently produced by either the press, sinter, and heat treat process or by conventional machining of a casting or wrought material.

A free piston internal combustion engine coupled with a linear generator is proposed for hybrid vehicle application. The engine works on CI two-stroke cycle with direct fuel injection. Uniflow was chosen for an efficient scavenge process. The exhaust valve timing and lift are to be dynamically controlled by electromechanical driven poppet valves, developed by FEV. A numerical simulation model of the proposed engine has been generated in this paper. The piston dynamics, cylinder scavenge process, combustion process, and friction characteristics are coupled together for systematic analysis with the code. It is meant to be a tool for prediction and optimization of the engine design and control parameters, such as fuel injection timing, valve/port timing, and electric power output. The analysis results are discussed in this paper.

Sinterhardening has proven to be an efficient and cost saving way to manufacture high strength components f.e. for gear boxes in an environmetally friendly manner. Material investigations showed that diffusion alloyed materials generally proved to be less sensitive to the hardening conditions and geometry than prealloyed materials either regarding hardness or dimensional change. As sizing of components is difficult to impossible in the sinterhardened condition, shrinkage or swelling has a decisive effect on the final dimensional stability. Compared to casehardening sinterhardening requires a significantly higher alloy content of f.e. Ni or Mo. Despite this particular cost disadvantage, the overall process provides lower costs at similiar strength levels and better tolerances.

Transfer case sprockets usually require quenching to improve hardness and mechanical properties. This additional process step can be avoided with sinter hardening. Indeed, sinter hardening allows the production of P/M parts with high strength and apparent hardness directly from sintering because the martensitic transformation takes place during the cooling portion of the sintering operation. Therefore, this process eliminates the need for a post-sintering heat treatment with all the inherent related problems such as part distortion, oil contamination and added processing costs. Many low alloy steel powders have been developed for sinter hardening applications. These materials, combined with the availability of sintering furnaces equipped with enhanced cooling capacity, make sinter hardening particularly attractive for parts that are difficult to quench because of their size and shape.

The influence of sintering parameters on mechanical properties of three different sinterhardenable grades of powder has been studied. Dimensional change, hardness, strength, and microstructure of specimens were evaluated in different sintering conditions, such as temperature, belt speed, and cooling rate. Conclusions were used to convert a major line of sprockets from a traditional mold, sinter, size, and quench process to a cost effective mold and sinterhard one. Mechanical tests, such as crush tests and engine tests were performed on real parts manufactured using both processes, confirming the validity and the benefits of this conversion.

Using data from the National Automotive Sampling System/Crashworthiness Data System (NASS/CDS) for1995-96, this study updates previous analyses of driver fatalities in airbag-equipped vehicles in the NASS/CDS database for 1989-93 and 1989-94. A total of 59 cases of frontal crashes of airbag-equipped vehicles with driver fatalities were identified in these 8 years of NASS/CDS data, but in 9 cases the fatalities were not related to the impacts (e.g., fire, medical condition). Vehicle intrusion was the cause of the fatal injuries in 27 cases, and 7drivers died from injuries sustained when they were either partially or totally ejected from their vehicles. There was one case in which the airbag did not deploy, although the crash conditions indicated it should have. One driver died from contact with a nonintruding vehicle surface, and the causes of the fatal injuries in 5 cases were unknown.

The use of P/M stainless steel components in automotive exhaust systems continues to grow rapidly. These P/M components have met the stringent requirements demanded for these applications which were formerly only provided by wrought materials. These high density components are being required to pass specific qualification tests designed by OEM's and Tier 1's - Galling, Hot Vibration Leak and High Temperature Oxidation/Corrosion Tests. This paper discusses the performance of P/M stainless steel exhaust flanges and HEGO bosses in a number of OEM and Tier 1 specified performance tests.

The effects of hybridization on heavy-duty vehicles are not well understood. Heavy vehicles represent a broader range of applications than light-duty vehicles, resulting in a wide variety of chassis and engine combinations, as well as diverse driving conditions. Thus, the strategies, incremental costs, and energy/emission benefits associated with hybridizing heavy vehicles could differ significantly from those for passenger cars. Using a modal energy and emissions model, we quantify the potential energy savings of hybridizing commercial Class 3-7 heavy vehicles, analyze hybrid configuration scenarios, and estimate the associated investment cost and payback time.

This paper describes a semi-theoretical simulation model, CYCLE11_CO2, for a transcritical carbon dioxide vapor-compression refrigeration cycle. CYCLE11_CO2 is based on an earlier simulation model, CYCLE11-UA, developed at the National Institutes of Standards and Technology for evaluating alternative refrigerants and refrigerant mixtures. Here we describe CYCLE11_CO2, its inputs, its outputs, and present some typical simulation results. The simulation results are compared to experimental data.

Theromophotovoltaic generators are a convenient solution to extend the range of commercial electric vehicles. High efficiencies and small volumes are required for this application. This paper shows how this problem can be addressed by using a new generation of photovoltaic cells based on quantum low-dimensional structures. Their advantage over the conventional (single gap) cells are remarkable, particularly for the conversion of narrow-band infrared radiation, produced by a combustor coupled to a selective emitter at about 1500K-1800K.

Due to the future application of combustion engines in small and hybrid vehicles, the demand for high efficiency with low mass and compact engine design is of prime importance. The diesel engine, with its outstanding thermal efficiency, is a well suited candidate for such applications. In order to realize these targets, future diesel engines will need to have increasingly higher specific output combined with increased power to weight ratios. This is therefore driving the need for new designs of 3 and/or 4 cylinder, small bore engines of low displacement, sub 1.5l. Recent work on combustion development, has shown that combustion systems, ports, valves and injector sizes are available for bore sizes down to 65 mm.

This paper presents a new hybrid propulsion system that has been developed to address environmental issues related to the automotive powertrain, based on the view that such systems will be a core automotive technology in the future. To achieve market acceptance, it is essential that hybrid systems do not compromise engine performance or driving performance. The following target performance characteristics were considered to be important in the development of this hybrid propulsion system for the Japanese market. First, driving performance should not be sacrificed for the mere reason that it is a hybrid car. Second, fuel economy should be twice that of gasoline-powered vehicles in the same class under 10-15 test mode operation, or even better. Further, performance in other areas should be comparable to conventional vehicles. The system presented here has two motors for propulsion and energy regeneration. Both are inverter type permanent magnetic synchronous motors.

Hybrid electric vehicle with internal combustion engine fueled with hydrogen can be a competitor to the fuel cell electric vehicle that is thought to be the ultimately clean and efficient vehicle. The objective in this research is to pursue higher thermal efficiency and lower exhaust emissions in a hydrogen-fueled engine for the series type hybrid vehicle system. Influences of compression ratio, surface / volume ratio of combustion chamber, and boost pressure on thermal efficiency and exhaust emissions were analyzed. Results showed that reduction of the surface / volume ratio by increased cylinder bore was effective to improve indicated thermal efficiency, and it was possible to achieve 44% of indicated thermal efficiency. However, brake thermal efficiency resulted in 35.5%. It is considered that an improved mechanical efficiency by an optimized engine design could increase the brake thermal efficiency largely.

Two parallel HEV control concepts: ‘thermostat’ and ‘power split’ are compared in this paper. To achieve a substantial improvement in fuel economy, the ‘thermostat’ or ‘on/off’ control technique intended to improve the fuel efficiency of a series HEV has been adopted and designed for parallel HEV. Among different ‘power split’ concepts developed for parallel hybrids only the ‘electrically assist’ algorithm is considered in this paper. These two control concepts are compared for three parallel HEV architectures: pre-transmission, post-transmission and continuous variable transmission hybrids. The comparison study also includes the effect of hybridization factor-the ratio of the electric power to the total propulsion power. The matrices of comparison are level of performance, energy consumption and exhaust emissions. The SAE J1711 partial charge test procedure is followed.

A regenerative braking model for a parallel Hybrid Electric Vehicle (HEV) is developed in this work. This model computes the line and pad pressures for the front and rear brakes, the amount of generator use depending on the state of deceleration (i.e. the brake pedal position), and includes a wheel lock-up avoidance algorithm. The regenerative braking model has been developed in the symbolic programming environment of MATLAB/SIMULINK/STATEFLOW for downloadability to an actual HEV's control system. The regenerative braking model has been incorporated in NREL's HEV system simulation called ADVISOR. Code modules that have been changed to implement the new regenerative model are described. Resulting outputs are compared to the baseline regenerative braking model in the parent code. The behavior of the HEV system (battery state of charge, overall fuel economy, and emissions characteristics) with the baseline and the proposed regenerative braking strategy are first compared.

Numerical simulations of the flow inside a passenger compartment are compared with experimental data obtained from velocity field measurements using Particle Image Velocimetry (PIV). Comparisons are made in the front part of the passenger compartment with the air-distribution system operated in a ventilation mode. The sensitivty of the CFD-model to the boundary conditions was investigated and two different turbulence models were tested. Computations and experiments resulted in similar results for the overall flow field, however, rather large differences were found in the vertical spreading of the jet from the dashboard nozzle. The width of the jet was lower in the measurements than in the simulations. This difference is believed to be caused by the high diffusivity obtained when using a k-epsilon model in combination with an unstructured grid.

A traditional method of controlling evaporator superheat in a vapor compression air conditioning system is the thermostatic expansion valve (TXV). Such systems are often used in automotive applications. The TXV depends on superheat to adjust the valve opening. Unfortunately, any amount of superheat causes that evaporator to operate at reduced capacity due to dramatically lower heat transfer coefficients in the superheated region. In addition, oil circulation back to the compressor is impeded. The cold lubricant almost devoid of dissolved refrigerant is quite viscous and clings to the evaporator walls. A system that could control an air conditioner to operate with no superheat would either decrease the size of its existing evaporator while maintaining the same capacity, or potentially increase its capacity with its original evaporator. Also, oil circulation back to the compressor would be improved.

The automatic climate control system has been developed to improve cabin thermal comfort. However it is getting very hard to develop more comfortable and high-level system with current techniques. This report introduces a completely new automatic climate control system utilized an applied “Neural Network” to achieve highly flexible thermal comfort.

Current systems of air diffusion inside the car cabin are leading in some conditions to passenger discomfort. To solve this problem our company has developed a new concept of air diffusion. It consists in an air distribution system composed of a wide central air diffusion area on the top of the instrument panel and two lateral outlets. To evaluate the comfort performances of the concept a methodology based on experiments, simulation and subjective evaluation has been defined and used. The comparison between the current air diffusion and the new one shows a significant impact on the driver's and passenger's comfort. The purpose of this paper is to describe the methodology developed to analyze the air diffusion impact on the comfort and the improvements obtained by the new concept.