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Vehicles have been more required to save energy against the background of the tendency of ecology. As the result of improving efficiency of internal combustion engines and adoption of electric power train, heat loss from engine coolant, which is used to heat the cabin, decreases and consequently additional energy may be consumed to maintain thermal comfort in the passenger compartment in winter. This paper is concerned with the humidity control system that realizes reduction of ventilation heat loss by controlling recirculation rate of the HVAC system by using highly accurate humidity sensor to evaluate risk of fogging on the windshield. As the results of the control, fuel consumption of hybrid vehicles decreases and maximum range of electric vehicles increases.

The effects of diesel fuel properties (aromatic content, cetane index and T90), cetane improver, oxygenates, high boiling point hydrocarbons and aromatics distribution on diesel exhaust emissions were studied under the Japanese 10-15 test cycle and the ECE+EUDC test cycle. The test vehicle was a TOYOTA COROLLA with a natural aspirated, 2.0L displacement, IDI diesel engine. It was demonstrated that particulate emissions are highly correlated with T90 and that NOx is affected by the aromatic content of fuel. A reduction in particulates emissions was observed in fuel with a lower cetane number by adding cetane improver, but this reduction was limited. Cetane improver had no effect on NOx emissions in the 45 # 60 cetane number range. Oxygenates reduced particulate emissions remarkably but had little effect on NOx emissions. A decrease in the soot in particulates was particularly observed.

Roadway departure mitigation systems for helping to avoid and/or mitigate roadway departure collisions have been introduced by several vehicle manufactures in recent years. To support the development and performance evaluation of the roadway departure mitigation systems, a set of commonly seen roadside surrogate objects need to be developed. These objects include grass, curbs, metal guardrail, concrete divider, and traffic barrel/cones. This paper describes how to determine the representative color of these roadside surrogates. 24,762 locations with Google street view images were selected for the color determination of roadside objects. To mitigate the effect of the brightness to the color determination, the images not in good weather, not in bright daylight and under shade were manually eliminated. Then, the RGB values of the roadside objects in the remaining images were extracted.

A new automotive interior component material, TSOP-5 has been developed by refining the technology utilized to develop TSOP-1, the high modulus and high flow material for bumper covers. This new interior component material has excellent molding capability (MI=30dg/min.) yet still maintains high impact resistance which enables the material to be used in areas such as the dash board as well as trim covers requiring to meet the FMVSS 214, the new side impact regulation or the FMVSS 201, the new soft upper trim regulation.

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.

The measuring method of vehicular particulate matter (PM) size distribution to simulate the atmospheric dilution process was studied. PM size distribution was measured with a scanning mobility particle sizer (SMPS). To simulate the atmospheric dilution process with a chassis dynamometer test, a chasing experiment was done in order to obtain reference data. A light duty diesel truck was selected as a basic test vehicle. Three sizes of prototype partial flow diluters (PPFD) were made to reproduce the PM size in the atmosphere. The PM sizes of the chasing experiment and the PPFD experiment was roughly agreed. Differences in the data obtained from a full flow dilution tunnel and the chasing experiments were investigated. The length of the transfer tube greatly affected the smaller side of the PM number concentration.

The combustion chamber deposit (CCD) forming tendency of gasoline components and detergents were investigated with laboratory tests ad engine dynamometer tests. In the dynamometer tests, the driving conditions under which fuels and detergents influence CCD formation were specified, and the effects of different gasoline components and detergent blends on CCD formation were examined. In the laboratory tests, the CCD forming process was investigated thoroughly [10]. The CCD forming tendency of aromatic compounds in gasoline were dependent not only on physical properties such as molecular weight, but also chemical structure (number or position of the alkyl substituents of aromatic molecules). As for oxygenates, engine dynamometer tests with MTBE blended gasoline yielded less CCD than the test without MTBE. The CCD forming tendency of detergents correlated with the thermal decompositon tendency of the detergent package and the concentration of the main agents.

In Biodiesel Fuel Research Working Group(WG) of Japan Auto-Oil Program(JATOP), some impacts of high biodiesel blends have been investigated from the viewpoints of fuel properties, stability, emissions, exhaust aftertreatment systems, cold driveability, mixing in engine oils, durability/reliability and so on. This report is designed to determine how high biodiesel blends affect oil quality through testing on 2005 regulations engines with DPFs. When blends of 10-20% rapeseed methyl ester (RME) with diesel fuel are employed with 10W-30 engine oil, the oil change interval is reduced to about a half due to a drop in oil pressure. The oil pressure drop occurs because of the reduced kinematic viscosity of engine oil, which resulting from dilution of poorly evaporated RME with engine oil and its accumulation, however, leading to increased wear of piston top rings and cylinder liners.

The reduction of particulate emissions is one of the most important challenges facing the development of future gasoline engines. Several studies have demonstrated the impact of fuel chemical composition on the emissions of particulate matter, more particularly, the detrimental effect of high boiling point components such as heavy aromatics. Fuel contamination is likely to become a critical issue as new regulations such as Real Driving Emissions RDE involves the use of market fuel. The objective of this study is to investigate several experimental approaches to detect the presence of Diesel contamination in Gasoline which is likely to alter pollutant emissions. To achieve this, a fuel matrix composed of 12 fuels was built presenting diesel fuel in varying concentrations from 0.1 to 2% v/v. The fuel matrix was characterized using several original techniques developed in this study.

Improving the engine efficiency to respond to climate change and energy security issues is strongly required. In order to improve the engine efficiency, lower fuel consumption, and enhance engine performance, OEMs have been developing high compression ratio engines and downsized turbocharged engines. However, higher compression ratio and turbocharging cause cylinder pressure to increase, which in turn increases the demand voltage for ignition. To reduce the demand voltage, a new ignition system is developed that uses a high voltage Zener diode to maintain a constant output voltage. Maintaining a constant voltage higher than the static breakdown voltage helps limit the amount of overshoot produced during the spark event. This allows discharge to occur at a lower demand voltage than with conventional spark ignition systems. The results show that the maximum reduction in demand voltage is 3.5 kV when the engine is operated at 2800 rpm and 2.6 MPa break mean effective pressure.

The potential of high efficiency zero-emission engines fueled by hydrogen, which is regarded as a promising form of energy for the future, is being researched. The argon circulated hydrogen engine [ 1 ] is one system theoretically capable of achieving both high efficiency and zero emissions, and its feasibility for use in vehicles has been studied. Specifically, tests were performed to verify the following issues. It was examined whether stable hydrogen combustion could be achieved under an atmosphere of argon and oxygen, which has a high specific heat ratio, and whether the substantial thermal efficiency improvement effect of the argon working gas could be achieved. An argon circulation system was also studied whereby steam, which is the combustion product of the hydrogen and oxygen emitted from the engine, is separated by condensation to enable the remaining argon to be re-used.

The change of the fuel flow rate in an injector with mileage accumulation causes poor drivability and exhaust emission deterioration in Otto-type methanol fueled vehicles with a multi-point fuel injection system. This is one of the serious problems which needs to be solved for the practical use of methanol fueled vehicles. The investigation results reveal that the wear of contact surfaces between a valve needle and a valve body increases the resistance force for valve needle movement and causes the change of dynamic fuel flow rate in the injector. The effects of several countermeasures to solve this problem are evaluated.

Catalyst specifications and converter layouts were studied to identify the high conversion performance under various in-use driving conditions, high mileage intervals and extended life cycle. The effects of volumes, configuration, selection and loading distribution of precious metals, additive components and substrate type for catalyst were studied on engine dynamometers and vehicle tests to optimize a catalyst converter system. Moreover, model gas experiments were conducted to analyze deterioration mechanisms and conversion characteristics of catalysts. As a result, the concept of a divided catalyst converter system, which provides separate functions for a close-coupled and an under-floor catalyst, was found to be effective for the future exhaust system. For reducing HC emissions, the close-coupled catalyst should warm up quickly and resist a high temperature. The under-floor catalyst, located at a rather low temperature position, is durable and maintains high NOx conversion.

In this study, we combined a diesel engine with the Toyota Hybrid System (THS). Utilizing the functions of the THS, reducing engine friction, lowering the compression ratio, and adopting a low pressure loop exhaust gas recirculation system (LPL-EGR) were examined to achieve both low fuel consumption and low nitrogen oxides (NOx) emissions over a wide operating range. After applying this system to a test vehicle it was verified that the fuel economy greatly surpassed that of a conventional diesel engine vehicle and that NOx emissions could be reduced below the value specified in the Euro 6 regulations without DeNOx catalysts.

As the demand for improved fuel economy increases and new CO2 regulations have been issued, aerodynamic drag reduction has become more critical. One of the important factors to consider is cooling drag. One way to reduce cooling drag is to decrease the air flow volume through the front grille, but this has an undesirable impact on cooling performance as well as component heat load in the under-hood area. For this reason, cooling drag reduction methods while keeping reliability, cooling performance and component heat management were investigated in this study. At first, air flow volume reduction at high speed was studied, where aerodynamic drag has the greatest influence. For vehicles sold in the USA, cooling specification tends to be determined based on low speed, while towing or driving up mountain roads, and therefore, there may be extra cooling capacity under high speed conditions.

Recently, the California Air Resources Board (CARB) has proposed a new set of evaporative emissions and “Useful Life” standards, called LEVII EVAP regulations, which are more stringent than those of the enhanced EVAP emissions regulations. If the new regulations are enforced, it will become increasingly important for the carbon canister to reduce Diurnal Breathing Loss (DBL) and to prevent deterioration of the canister. Therefore, careful studies have been made on the techniques to meet these regulations by clarifying the working capacity deterioration mechanism and the phenomenon of DBL in a carbon canister. It has been found that the deterioration of working capacity would occur if high boiling hydrocarbons, which are difficult to purge, fill up the micropores of the activated carbon, and Useful Life could be estimated more accurately according to the saturated adsorption mass of the activated carbon and the canister purge volume.

One-box type vehicles are especially liable to a loss of stability when entering a region of cross-wind. The reasons for this instability were investigated using scale models and by means of a mathematical simulation. Results indicated that yawing moment attains a peak at a precise position of the vehicle relative to the cross-wind. Visualization of the air flow and measurement of the pressure distributions established the cause of the phenomenon. Furthermore a study was conducted into the effects of body shape on stability and the efficacy of various modifications was assessed.

The emission characteristics of hydrocarbons during the cold start and the warm-up have been investigated. Timed sampling of hydrocarbon emissions upstream and downstream of a close-coupled catalytic converter have been carried out. The experimental results show that the emission characteristics of hydrocarbons are influenced by both the engine operating conditions and the heating characteristics of the catalytic converter. In the case of engine-out hydrocarbons, the total amount of hydrocarbons drastically decreases but the percentage contribution of the C2-C4 olefins to the engine-out hydrocarbons increases as the warm-up proceeds. Since these olefins have relatively high maximum incremental reactivity (MIR) factors, the specific reactivity (SR) of the engine-out hydrocarbons gradually increases during the warm-up. The adsorption and desorption processes of the engine-out hydrocarbons on the catalyst occur before the catalyst light-off.

The higher compression ratio engines, two-stroke engines and flexible fuel vehicles currently under development tend to face the problems of spark plug fouling owing to the necessity of using cold type spark plugs. This paper analyzes the sparking of fouled spark plugs and investigates the characteristics required of an ignition system in order to avoid fouling problems. The results clearly establish that to maintain a strong spark even when the plug is fouled, a high voltage should be instantaneously applied to the spark plug. A series-gap on the high-tension side was confirmed to be an effective means of achieving this and a new plug cap provided with a series-gap has resolved fouling problems such as failure to start. Lately, fuel economy and long-term energy conservation have become critically important. For automobiles, higher compression ratio engines, two-stroke engines and flexible fuel vehicles (FFVs) are being developed.

The emission regulations for diesel engines are continually becoming stricter to reduce pollution and conserve energy. To meet these increasingly stringent regulations, a new exhaust after-treatment device is needed. Recently, the authors proposed the simultaneous electrochemical reduction (ECR) system for diesel particulate matter (PM) and NOx. In this method, a gas-permeable electrochemical cell with a porous solid oxide electrolyte is used for PM filtering on the anode. Alkaline earth metal is coated on the cathode for NOx storage. Application of voltage to both electrodes enables the simultaneous reduction of PM and NOx by the forced flow of oxygen ions from the cathode to the anode (oxygen pumping). In this study, the basic characteristics of the ECR system were investigated, and a disk-shaped electrochemical cell was evaluated.