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At present, biodiesel fuels using natural-origin materials are expanding in share, and there are many different kinds. Biodiesel fuel generates organic acid when it deteriorates, so care is needed when evaluating the influence of the fuel on automotive fuel-line materials. A model biodiesel fuel was designed taking into account deterioration of the fuel and mixing of impurities into it. Durability of automotive fuel-line rubber and plastic materials were evaluated by using the model fuel. From the evaluation results, it was found that fluoroelastomer (hereafter referred to as FKM) and polyacetal resin (hereafter referred to as POM) deteriorate depending on specific fuel properties and deterioration state. In this paper, we report evaluating results of biodiesel fuels on the automotive fuel-line rubber and plastic materials, and the importance of biodiesel fuel property management.

Appropriate emergency response information is required for first responder before hydrogen fuel cell vehicles will become widespread. This paper investigates experimentally the hydrogen dispersion in the vicinity of a vehicle which accidentally releases hydrogen horizontally with a single volumetric flow of 2000 NL/min in the under-floor section while varying cross and frontal wind effects. This hydrogen flow rate represents normally a full throttle power condition. Forced wind was about maximum 2 m/s. The results indicated that the windward side of the vehicle was safe but that there were chiefly two areas posing risks of fire by hydrogen ignition. One was the leeward side of the vehicle's underbody where a larger region of flammable hydrogen dispersion existed in light wind than in windless conditions. The other was the area around the hydrogen leakage point where most of the leaked hydrogen remained undiffused in an environment with a wind of no stronger than 2 m/s.

The localized fire test provided in the Global Technical Regulation for Hydrogen Fuel Cell Vehicles gives two separate test methods: the ‘generic installation test - Method 1′ and the ‘specific vehicle installation test - Method 2′. Vehicle manufacturers are required to apply either of the two methods. Focused on Method 2, the present study was conducted to determine the characteristics and validity of Method 2. Test results under identical burner flame temperature conditions and the effects of cylinder protection covers made of different materials were compared between Method 1 and Method 2.

Downsizing or higher compression ratio of SI engines is an appropriate way to achieve considerable improvements of part load fuel efficiency. As the compression ratio directly impacts the engine cycle thermal efficiency, it is important to increase the compression ratio in order to reduce the specific fuel consumption. However, when operating a highly boosted / downsized SI engine at full load, the actual combustion process deviates strongly from the ideal Otto cycle due to the increased effective loads requiring ignition timing delay to suppress abnormal combustion phenomena such as engine knocking. This means that for an optimal design of an SI engine between balances must be found between part load and full load operation. If the knocking characteristic can be accurately predicted beforehand when designing the combustion chamber, a reduction of design time and /or an increase in development efficiency would be possible.

In order to clarify future automobile technologies and fuel qualities to improve air quality, second phase of Japan Clean Air Program (JCAPII) had been conducted from 2002 to 2007. Predicting improvement in air quality that might be attained by introducing new emission control technologies and determining fuel qualities required for the technologies is one of the main issues of this program. Unregulated material WG of JCAPII had studied unregulated emissions from gasoline and diesel engines. Eight gaseous hydrocarbons (HC), four Aldehydes and three polycyclic aromatic hydrocarbons (PAHs) were evaluated as unregulated emissions. Specifically, emissions of the following components were measured: 1,3-Butadiene, Benzene, Toluene, Xylene, Ethylbenzene, 1,3,5-Trimethyl-benzene, n-Hexane, Styrene as gaseous HCs, Formaldehyde, Acetaldehyde, Acrolein, Benzaldehyde as Aldehydes, and Benzo(a)pyrene, Benzo(b)fluoranthene, Benzo(k)fluoranthene as PAHs.

Water management is one of the key factors to ensure high performance, cold start and durability of polymer electrolyte fuel cells (PEFCs), and it is important to understand the behavior of liquid water in PEFCs. X-ray computed tomography (X-ray CT) imaging and the two-phase lattice Boltzmann method (two-phase LBM) are applied to analyze the mechanism of water transport in the gas diffusion layers (GDLs) and the gas channels in generating PEFCs. The results of the two-phase LBM are compared with those of X-ray CT imaging, and are found to agree qualitatively in that water is discharged along the hydrophilic channel wall and accumulated in the GDL, especially under the rib. The effects of the wettability of the GDLs, and of the gas channels, the diameter of the carbon fibers, and the porosity of the GDLs on water discharge from the GDLs and gas channels are also investigated.

A second-generation power control unit (PCU) for a two-motor hybrid system is proposed. An optimally designed power module, which is a key component of the PCU, is applied to increase heat-resistant temperature, while the basic structure of the first generation is retained and the power semiconductor chip is directly cooled from the single side. In addition to the optimum design, by decreasing the power loss as well as increasing the heat-resistant temperature of the power semiconductors (IGBT: Insulated Gate Bipolar Transistor and FWD: Free Wheeling Diode), the proposed PCU has attained 25% higher power density and 23% smaller size compared to first-generation units, maintaining PCU efficiency (fuel economy). To achieve a high yield rate in the power module assembly process, a new screening technology is adopted at the initial stage of power module manufacturing.

An investigation based on human visual search functions was conducted into the causative factors of traffic accidents at clear intersections in rural areas. The results indicated that it is difficult for drivers to detect a vehicle traveling on a collision course because the vehicle remains in the same position in the driver's visual field. Two systems are introduced to assist drivers' visual searches. One system uses an image processing technique, and the other utilizes DGPS and IVC techniques. This paper presents the development of the assistance system.

If a compressed hydrogen tank for vehicles is filled with hydrogen gas more quickly, the gas temperature in the tank will increase. In this study, we conducted hydrogen gas filling tests using the TYPE 3 and TYPE 4 tanks. During the tests, we measured the temperature of the internal liner surface and investigated its relationship with the gas temperature in the tank. We found that the gas temperature in the upper portion of the TYPE 4 tank rose locally during filling and that the temperature of the internal liner surface near that area also rose, resulting in a temperature higher than the gas temperature at the center of the tank. To keep the maximum temperature in the tank below the designed temperature (85°C) during filling and examine the representative tank internal temperatures, it is important to examine filling methods that can suppress local rises of tank internal temperature.

In recent years, the increased use of electric power steering in vehicles has increased the importance of issues such as making systems more compact and lightweight, and dealing with increased development man-hours. To increase development efficiency, the use of a “Hardware in the loop simulator” (HILS) is being tested to shift from the previous development method that relied on a driver's subjective evaluation in an actual vehicle test to bench-test development. Using HILS enables tasks such as specification studies, performance forecasts, issue identification and countermeasure proposals to be performed at an early stage of development even when there is no prototype vehicle. This report describes a case study of using HILS to solve the issues of reducing the load by adjusting the geometric specifications around the kingpin and eliminating the tradeoff by adding a new EPS control algorithm in order to make the electric power steering (EPS) more compact and lightweight.

A sports car exhibits many challenges from an aerodynamic point of view: drag that limits top speed, lift - or down force - and balance that affects handling, brake cooling and insuring that the heat exchangers have enough air flowing through them under several vehicle speeds and ambient conditions. All of which must be balanced with a sports car styling and esthetic. Since this sports car applies two electric motors to drive front axle and a high-rev V6 turbo charged engine in series with a 9-speed double-clutch transmission and one electric motor to drive rear axle, additional cooling was required, yielding a total of ten air cooled-heat exchangers. It is also a challenge to introduce cooling air into the rear engine room to protect the car under severe thermal conditions. This paper focuses on the cooling and heat resistance concept.

The weight-saving requirements for automobiles are important. In order to produce a lighter engine, an aluminum block with cast-iron liners and a hypereutectic aluminum-silicon alloy block have been developed. (1)*, (2), (3), (4), (5), (6) We developed a new aluminum engine block which has the cylinder bore surface structure reinforced with short ceramic fiber. We also established technology suitable for mass-production including a fiber preform process and a non-destructive inspection method. In this paper, the optimum properties and production technology of MMC engine blocks are introduced. A portion of the paper is dedicated to the results of a comparison study between a new light-weight aluminum engine block, a hypereutectic aluminum-silicon engine block and an aluminum engine block with cast-iron liners.

A method of predictive simulation of flow-induced noise using computational fluid dynamics has been developed. The goal for the developed method was application in the vehicle development process, and the target of the research was therefore set as balancing the realization of a practical level of predictive accuracy and a practical computation time. In order to simulate flow-induced noise, it is necessary to compute detailed eddy flows and changes in the density of the air. In the research discussed in this paper, the occurrence or non-occurrence of flow-induced noise was predicted by conducting unsteady compressible flow calculation using large eddy simulation, a type of turbulence model. The target flow-induced noise for prediction was narrow-band noise, a type of noise in which sound increases in specific frequency ranges.

The moment of inertia of the crankshaft cannot be ignored when analyzing the dynamics of a motorcycle. In this research, the tire friction force (calculated by drag and tire side force) was used as an index of the drive performance. The ratio of roll rate and steering torque (here after referred to as a roll rate gain) was used as an index of the cornering performance, and it was analyzed as the influence of the moment of inertia of a crankshaft on the drive performance as well as cornering performance. As a result, the influence on drive performance and cornering performance by the moment of inertia has been found.

The reduction of fuel consumption is of great importance to automobile manufacturers. As a prospective means to achieve fuel economy, lean burn is being investigated at various research organizations and automobile manufacturers and a number of studies on lean-burn technology have been reported to this date. This paper describes the development of a four-valve lean-burn engine; especially the improvement of the combustion, the development of an engine management system, and the achievement of vehicle test results. Major themes discussed in this paper are (1) the improvement of brake-specific fuel consumption under partial load conditions and the achievement of high output power by adopting an optimized swirl ratio and a variable-swirl system with a specially designed variable valve timing and lift mechanism, (2) the development of an air-fuel ratio control system, (3) the improvement of fuel economy as a vehicle and (4) an approach to satisfy the NOx emission standard.

We had developed Electric Servo Brake System, which can control brake pressure accurately with a DC motor according to brake pedal force. Therefore, the system attains quality brake feeling while reflecting intentions of a driver. By the way, “Build-up” is characteristics that brake effectiveness increases in accordance with the deceleration of the vehicle, which is recognized as brake feeling with a sense of relief as not to elongate an expected braking distance at a downhill road due to large-capacity brake pad such as sports car and large vehicles. Then, we have applied the optical characteristic control to every car with Electric Servo Brake System by means of brake pressure control but not brake pad. Hereby, we confirmed that the control gives a driver the sense of relief and the reduction of pedal load on the further stepping-on of the pedal. In this paper, we describe the development of brake feel based on the control overview.

Test procedures for evaluating vehicle compatibility were investigated based on accident analysis and crash tests. This paper summarizes the research reported by Japan to the IHRA Compatibility Working Group. Passenger cars account for the largest share of injuries in head-on collisions in Japan and were identified as the first target for tackling vehicle compatibility in Japan. To ascertain situations in collisions between vehicles of different sizes, we conducted crash tests between minicars and large cars, and between small cars and large cars. The deformation and acceleration of the minicar and small car is greater than that of large car. ODB, Overload and MDB tests were performed as procedures for evaluating vehicle compatibility. In overload tests, methods to evaluate the strength of the passenger compartment were examined, and it is found that this test procedure is suitable for evaluating the strength of passenger compartments.

The distribution of concentrations of hydrogen leaking into the front compartment and the dispersion after the leak was stopped were investigated to obtain basic data for specifying the mounting positions of hydrogen leak detecting sensors and the threshold values of alarms for compressed hydrogen vehicles. Ignition tests were also conducted to investigate the flammability and the environmental impact (i.e. the impact on human bodies). These tests were also conducted with methane to evaluate the protection against hydrogen leaks in vehicles in comparison with natural gas (methane). We found that the concentration of hydrogen in the front compartment reached 23.7 vol% maximum when hydrogen gas was allowed to leak for 600 sec from the center of the bottom of the wheelbase at a rate of 131 NL/min, which is the allowable limit for a fuel leak at the time of collision of compressed hydrogen vehicles in Japan.

Instantaneous temperature of in-cylinder gas provides a lot of useful and local information for analyzing the combustion process in an internal combustion engine. From the standpoint of applicability to a practical engine, the infrared monochromatic radiation pyrometry required only a single optical window is considered to be more suitable comparing with the conventional infrared absorption-emission pyrometry with two optical windows. Then, the former pyrometer is used to measure the mean gas temperatures averaged on an optical path (or cylinder diameter) of a spark ignition engine connected to a prechamber with a torch nozzle of various area sizes. These measured temperature-crankangle diagrams not only clarify the influences of torch jet flow on the combustion processes, but also correspond well to the heat release rates calculated from the pressure diagrams.

Diesel emissions are significant issue worldwide, and emissions requirements have become so tough that. the application of after-treatment systems is now indispensable in many countries To meet even more stringent future emissions requirements, it has become apparent that the improvement of market fuel quality is essential as well as the development in engine and exhaust after-treatment technology. Japan Clean Air Program II (JCAP II) is being conducted to assess the direction of future technologies through the evaluation of current automobile and fuel technologies and consequently to realize near zero emissions and carbon dioxide (CO2) emission reduction. In this program, effects of fuel properties on the performance of diesel engines and a vehicle equipped with two types of diesel NOx emission after-treatment devices, a Urea-SCR system and a NOx storage reduction (NSR) catalyst system, were examined.