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In order to further improve the performance of NOx storage-reduction catalysts (NSR catalysts), focus was placed on their high temperature performance deterioration via sulfur poisoning and heat deterioration. The reactions between the basicity or acidity of supports and the storage element, potassium, were analyzed. It was determined that the high temperature performance of NSR catalysts is enhanced by the interaction between potassium and zirconia, which is a basic metal oxide. Also, a new zirconia-titania complex metal oxides was developed to improve high temperature performance and to promote the desorption of sulfur from the supports after aging.

This paper introduces a minivan with a newly developed hybrid system known as THS-C (The Hybrid System - CVT). This hybrid system employs a highly efficient engine, a high performance exhaust emission control system, a high efficiency metal belt CVT, and a super efficient motor. System control of the engine, motor and CVT optimizes the operation of both the motor and the engine. With these improvements, this new vehicle achieves over 80% better fuel economy than a comparable conventional vehicle. Exhaust emissions are dramatically reduced using precision control during the engine starts and stops.

Ignition and combustion control of HCCI (Homogeneous Charge Compression Ignition) in DI (Direct Injection) Diesel Engine were examined. In this study, double injection technique was used by Common Rail injection system. The first injection was used as an early injection for fuel diffusion and to advance the changing of fuel to lower hydrocarbons (i.e. low temperature reaction). The second injection was used as an ignition trigger for all the fuel. It was found that the ignition of the premixed gas could be controlled by the second injection when the early injection was maintaining low temperature reaction. It was found that as the boost pressure increased, ignition timing advanced slightly and the rate of pressure increase markedly decreased. The rate of pressure increase is one of the factors concerning operation limit in this combustion. Therefore, the VNT (Variable Nozzle Turbo-charger) was applied to the production engine to allow boost pressure control.

To realize the high performance of the three-way catalyst, this development focused on the heat resistance of the CeO2-ZrO2 solid solution (CZ) that possesses the oxygen storage capacity (OSC). A new concept of the OSC compound with high durability is proposed. We devised a new method of inhibiting the coagulation of the primary CZ particles by placing diffusion barrier layers made of alumina among the primary CZ particles. This material is called “ACZ”. The specific surface area of ACZ was larger than that of the conventional CZ after durability test. The sintering of Pt on the ACZ-added catalyst is inhibited and the crystal size of CZ in the ACZ-added catalyst is smaller than that in the CZ-added catalyst. The OSC and the light off temperature of the ACZ-added catalyst are improved.

A new rubber recycling technology to produce a thermoplastic elastomer (TPE) based on ethylene-propylene-diene rubber (EPDM) waste was developed. In this technology, the developed process consists of devulcanization of EPDM waste, blending of the devulcanized EPDM and polypropylene (PP), and dynamic vulcanization of the rubber component. All three are set up in as a continuous process in which the Recycled Rubber based Thermoplastic Elastomer (which is indicated as “RR-TPE” henceforth) is finally obtained. The RR-TPE exhibits elasticity and mechanical properties similar to those of commercial Thermoplastic olefins (TPO). These properties may be due to a suitably formed phase structure. Automotive parts are being developed and are going to be produced with the RR-TPE manufactured by this new technology. This technology will contribute to both protecting the environment and saving resources.

The UNIBUS (Uniform Bulky Combustion System) based on the HCCI (Homogeneous Charge Compression Ignition) concept uses an early injection quantity, timing, boost pressure, EGR, etc. for ignition control [1]. To further expand the operation range from the present level, the effects of the atmospheric conditions on ignition and combustion were calculated using CHEMKIN in the present study. When controlling the start timing of the high temperature reaction to suppress the early ignition, it is more effective to apply EGR than boost pressure. If fuel quantity is increased to expand load, it is possible to suppress a sharp cylinder pressure rising rate by increasing the boost pressure. Furthermore, it has become apparent that the cause of this is an increase in heat capacity.

An air-mix type 2-hole injector has been developed for 4-valve engines. In order to finely atomize the fuel whilst maintaining the separation of the twin sprays that assures minimal wetting of the partition between the siamese ports, the location of the air inlet passages was optimized and studies were conducted to determine the appropriate geometry of the fuel separation portion of the adapter. High speed photographs verify that the finalized adapter realizes centralized fuel flow through the splayed conduits so that the maximum air entrainment is achieved. This new injector both improves transient response and reduces HC emissions under all temperature conditions. It further enables injection timing to be retarded to the intake stroke at the same low HC level.

The effects of the phosphorus and sulfated ash contents of engine oils on the deactivation of monolithic three-way catalysts and oxygen sensors were studied. The effect of temperature was evaluated as well. The catalysts and oxygen sensors were poisoned in a 100-hour engine bench test. As a result, it was learned that engine oils with higher phosphorus contents showed a higher concentration of phosphorus on the catalyst surfaces, and the ability of the catalysts to convert carbon monoxide and oxides of nitrogen decreased. However, the phosphorus content was not observed to have any effect on hydrocarbons. The sulfated ash reduced the phosphorus concentration on the catalyst surface, but it also had a negative effect on the catalytic activity. The deactivation of the catalysts was much more noticeable at 800°C than at 720°C. In the tests at 720°C and 800°C, no deactivation of the oxygen sensors was observed, regardless of the composition of the engine oil.

A description is made of new control methods to improve response of wheel slip regulation. These methods enabled a new Traction Control (TRC) system based on throttle control rather than brake pressure to be developed. Major points are as follows: (1) Use of fuel injection cut-off to minimize delay (2) Additional adaptive throttle control logic By these means, a response nearly equal to that with brake pressure control is achieved at lower cost and with a considerable weight saving. Furthermore, the system, by suppressing noise and vibration, enhances the driver's control ability.

EXPERIMENTAL ANALYSIS for the increase of the radiator cooling air has been performed with special attention to the utilization of air pressure in high-speed running conditions. Measurements of pressure distributions at the radiator cooling air intake showed that the prevention of the occurrence of separations around the bumper is the efficient method to increase the cooling air. Furthermore, the optimum configuration for the radiator cooling air discharge has also been experimentally studied using a simplified model which simulates the under part of the engine compartment. These improvements made the vehicle radiator cooling air volume increase 14% under high-speed running conditions.

In order to realize higher response and lower emissions for 4-valve engines, TOYOTA has researched ways to homogenize the air-fuel mixture in the combustion chamber as well as to reduce intake port wall-wetting. To achieve these items we have developed an air-assisted type two-hole injector (air-assisted injector) system which has improved both fuel atomization and spray directions. This system has been introduced to a 3Liter V-6 passenger car engine and mass produced. The air-assisted injector atomizes the fuel by causing the air to collide and mix with the fuel. In order to obtain the air needed for atomization under all driving conditions, including idling, a new type idling speed control valve (ISCV) which has two air outlet passages has been developed. By means of this new ISCV, the new air-assisted injector system improves both fuel atomization and engine idling speed control during cold and hot engine conditions.

Recycling has become, and will continue to be one of the key technical issues for the automotive industry's role in protection of the global environment. Continued increases in vehicle registrations and use of non-metallic automotive materials will present a increasing opportunity for the utilization of currently wasted resources. Toyota has set up a management body and continues efforts to establish the necessary technologies and strategies for reduction and recovery of these wasted materials as valuable resources. Automakers worldwide are currently investigating numerous technically feasible recycling methodologies. These technologies may be useful for post-use vehicle recycling, but will require further development. It is important to focus current efforts on investigation of as many of these as possible in cooperation with related organizations.

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.

In order to adapt to energy security and the changes of global-scale environment, further improvement of fuel economy and adaptation to each country’s severer exhaust gas emission regulation are required in an automotive engine. To achieve higher power performance with lower fuel consumption, the engine’s basic internal design such as an engine block and cylinder head were changed and the combustion speed was dramatically increased. Consequently, stroke-bore ratio and valve layout were optimized. Also, both flow coefficient and intake tumble ratio port were improved by adopting a laser cladded valve seat. In addition, several new technologies were adopted. The Atkinson cycle using a new Electrical VVT (Variable Valve Timing) and new combustion technology adopting new multi-hole type Direct fuel Injector (DI) improved engine power and fuel economy and reduced exhaust emissions.

New 2A/F systems different from usual A/F-O2 systems are being developed to cope with strict regulation of exhaust gas. In the 2A/F systems, 2A/F sensors are equipped in front and rear of a three-way catalyst. The A/F-O2 systems are ideas which use a rear O2 to detect exhaust gas leaked from three-way catalyst early and feed back. On the other hand, the 2A/F systems are ideas which use a rear A/F sensor to detect nearly stoichiometric gas discharged from the three-way catalyst accurately, and to prevent leakage of exhaust gas from the three-way catalyst. Therefore, accurate detection of nearly stoichiometric gas by the rear A/F sensor is the most importrant for the 2A/F systems. In general, the A/F sensors can be classified into two types, so called, one-cell type and two-cell type. Because the one-cell type A/F sensors don’t have hysteresis, they have potential for higher accuracy.

The SEA model of wind noise requires the quantification of both the acoustic as well as the turbulent flow contributions to the exterior pressure. The acoustic pressure is difficult to measure because it is usually much lower in amplitude than the turbulent pressure. However, the coupling of the acoustic pressure to the surface vibration is usually much stronger than the turbulent pressure, especially in the acoustic coincidence frequency range. The coupling is determined by the spatial matching between the pressure and the vibration which can be described by the wavenumber spectra. This paper uses measured vibration modes of a vehicle window to determine the coupling to both acoustic and turbulent pressure fields and compares these to the results from an SEA model. The interior acoustic intensity radiating from the window during road tests is also used to validate the results.

This research aimed to identify how combustion characteristics are affected by the addition of hydrogen to methane, which is the main components of natural gas, and to study a combustion method that takes advantage of the properties of the blended fuel. It was found that adding hydrogen did not achieve a thermal efficiency improvement effect under stoichiometric conditions because cooling loss increased. The same result was obtained under EGR stoichiometric conditions. In contrast, under lean burn conditions, higher thermal efficiency and lower NOx than with methane combustion was achieved by utilizing the wide flammability range of hydrogen to expand the lean limit. Although NOx can be decreased easily by the addition of large quantities of hydrogen, the substantially lower energy density of the fuel causes a substantial reduction in cruising range. Consequently, this research improved the combustion of a CNG engine by increasing the tumble ratio to 1.8.

The study of 10% ethanol blended gasoline (E10 gasoline) utilization has been conducted in the Japan Auto-Oil Program (JATOP). In order to clarify the impact of E10 gasoline on vehicle performances, exhaust emissions, evaporative emissions, driveability and material compatibility have been investigated by using domestic gasoline vehicles including mini motor vehicles which are particular to Japan. The test results reveal that E10 gasoline has no impact on exhaust emissions, engine startup time and acceleration period under the hot start condition, but a slight deterioration is observed in some test cases under the cold start condition using E10 gasolines with 50% distillation temperature (T50) level set to the upper limit of Japanese Industrial Standards (JIS) K 2202. Regarding evaporative emissions, the tested vehicles shows no remarkable increase in the hot soak loss (HSL), diurnal breathing loss (DBL) and running loss (RL) testing with E10 gasolines.

Model based control design is an important method for optimizing engine operating conditions so as to simultaneously improve engines' thermal efficiency and emission profiles. Modeling of intake system that includes an intake throttle valve, an EGR valve and a variable geometry turbocharger was constructed based on conservation laws combined with maps. Calculated results were examined the predictive accuracy of fresh charge mass flow, EGR rate and boost pressure.

In this study, it is purpose to make clear the effect of cavitation phenomenon on the spray atomization. In this report, the cavitation phenomenon inside the nozzle hole was visualized and the pressure measurements along the wall of the nozzle hole were carried out by use of 25-times enlarged acrylic nozzle. For the representatives of regular gasoline, single and two-component fuels were used as a test fuel. In addition, various cavitating flow patterns same as experimental conditions were simulated by use of Barotropic model incorporated in commercial code of Star-CD scheme, and compared with experimental results.