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The efficiency of the NOx Storage and Reduction (NSR) catalysts used in the aftertreatment of diesel engine exhaust gases can potentially be increased by using reactive reductants such as CO and H₂ that are formed during in-cylinder combustion. In this study, a multi-dimensional computational fluid dynamics (CFD) code coupled with complex chemical analysis was used to study combustion with various fuel after-injection patterns. The results obtained will be useful in designing fuel injection strategies for the efficient formation of CO.

The purpose of this paper is to outline a new computer controlled transfer for four-wheel drive vehicles, which AISIN-WARNER LIMITED of Japan has developed in cooperation with TOYOTA MOTOR CORPORATION. Certain difficulties still remain with shafting of a conventional transfer. Coupled with a 4-speed automatic transmission, the new transfer discussed in this paper consists of 3 wet clutches, a simple planetary gear set, a chain for front drive and a control unit. This transmission-transfer combination (30-80LE) has realized “ON THE GO SHIFT” for easier operations of the 4WD applications.

By developing a mechanical-firing sensor using rotational inertia effect, we have completed miniaturization of the sensor and have developed a new-type mechanical-firing airbag system. This airbag system has been confirmed to have superior occupant protection performance after conducting a variety of vehicle crash tests and sled tests.

A very difficult problem exists regarding windshield shape, and that is to create a balance between aerodynamics and optical distortion. To assist in solving this problem, this study, concerning the characteristics of visual perception for the optical distortion when drivers receive visual information through a windshield, was carried out. In this study, the windshield area was divided into 4 zones from the viewpoints of the level of drivers' fixation frequency and types of objects observed. Distortion was defined as the gap angle ( distortion angle ), which crossed the lines of a grid board with and without a windshield, and distortion angles were measured on a total of 4 windshields. Four drivers indicated areas in each windshield in which they felt the area was distorted. As a result, the thresholds of optical distortion were shown as a function of the horizontal and vertical distortion angles by discriminatory analysis.

The authors developed a low-speed in-vehicle network for the body control system on passenger cars, where the most remarkable effects to reduce the number of wire harnesses could be expected. First, the authors analyzed the body control system to clarify the specifications required to build a low-speed in-vehicle network. Then the authors worked out optimum communication protocol, placing emphasis on cost reduction which is the key to expanding the applications of the low-speed in-vehicle network over wider fields. The low-speed in-vehicle network was evaluated for its performance through simulation and on-vehicle tests, and proved the practical validity of the concept. It was also verified that introducing the low-speed in-vehicle network has a satisfactory effect to reduce the number of wire harnesses.

In order to correspond to the exhaust emissions regulations that become severe every year, more advanced engine control becomes necessary. Engine engineers are concerned about the Hydrocarbons (HCs) that flow through the air-intake ports and that are difficult to precisely control. The main sources of the HCs are, the canister purge, PCV, back-flow gas through the intake valves, and Air / Fuel ratio (A/F) may be aggravated when they flow into the combustion chambers. The influences HCs give on the A/F may also grow even greater, which is due to the increasingly stringent EVAP emission regulations, by more effective ventilation in the crankcase, and also by the growth of the VVT-operated angle and timing, respectively. In order to control the A/F more correctly, it is important to estimate the amount of HCs that are difficult to manage, and seek for suitable controls over fuel injection and so on.

A multi-dimensional numerical method for predicting the warm-up characteristic of automobile catalytic converter systems was developed to effectively design catalytic converter systems which achieve low tail pipe emissions with satisfactory packagebility. The features of the method are; (1) consideration of the governing phenomena such as gas flow, heat transfer, and chemical reactions (2) capability of predicting warm-up characteristic for not only the catalytic converters but also the system as a whole during emission test modes such as the USA LA-4 mode. The description of the method is presented. The experimental verifications of the method were conducted to assure the accuracy of it. The effect of design parameters such as electrically heated catalyst (EHC), high loading of noble metal and thin honeycomb wall on warm-up characteristic of the catalyst are analyzed in the paper.

In the field of automotive body electronic control such as control of door locks, power windows, and wipers, there is a growing need of multiplexing communication to reduce the amount of wire harnesses. To meet this need, we developed a multiplexing communication protocol particularly suited to the body electronic control. Based on the developed protocol, we designed a communication control IC and a simple driver/receiver circuit with a few discrete components. The bus access method of the communication is the CSMA/CD with nondestructive bit arbitration, and its bit rate is 5 kbps. Its transmission media is a single wire. The communication IC has a multiplexing control block and a serial I/O block for an interface with a host CPU. It was fabricated using CMOS technology and has a chip of 2.6mm x 3.0mm in size that contains about 5,000 transistors. The driver/receiver circuit consists of one transistor, one capacitor and several resistors.

Electronic Control Units (ECUs) for automobiles are usually composed of a main single-chip microcomputer and peripheral circuits with some standard and/or custom ICs. The peripheral circuits vary with the kinds of control or models of automobiles. When the peripheral circuits are replaced with a single-chip microcomputer, the ECU becomes compact and low in cost. This is because the ECU is constructed with only two LSIs and can be used for various kinds of control and various models of automobiles only by changing the program of the microcomputer. The microcomputer, however, requires many I/O functions and high reliability. We have developed a new 4-bit microcomputer suitable for these requirements. The new microcomputer has two remarkable features. One is powerful I/O functions such as high speed I/O, serial I/O, parallel I/O, analog I/O, and default output that is generated in place of the calculated output by the main CPU when it fails.

A new 4.5 liter in-line 6 cylinder engine,1 FZ-FE has been developed for the Toyota Land Cruiser. To obtain high power, fuel efficient engine, we adopted the most advanced Toyota technologies, such as Toyota original 4 Valve DOHC system with scissors gear between camshafts, compact combustion chamber with smooth inlet and outlet system, KCS and so on. The engine produces 212 HP at 4600 rpm and 275 ft-lbs at 3200 rpm. Aluminum cylinder head,short skirt cylinder block stiffened with aluminum oil pan give the engine light weight and make it rigid enough to have low vibration and quietness. And we also designed every engine part appropriately so as to make the engine durable enough in severe operating condition of off-road vehicle.

Development of a new battery system for Toyota Estima Hybrid, the world's first minivan hybrid vehicle, has been completed. The battery pack that consists of 30 nickel metal hydride battery modules is compactly arranged under the 3rd seat in the cabin along with components such as the battery cooling blower and the ducts. This arrangement was designed in consideration of user's vehicle use, passengers' comfort and efficient battery-cooling performance.

Over the last few decades, in-cylinder visualization using optically accessible engines has been an important tool in the detailed analysis of the in-cylinder phenomena of internal combustion engines. However, most current optically accessible engines are recognized as being limited in terms of their speed and load, because of the fragility of certain components such as the elongated pistons and transparent windows. To overcome these speed and load limits, we developed a new generation of optically accessible engines which extends the operating range up to speeds of 6000 rpm for the SI engine version, and up to in-cylinder pressures of 20 MPa for the CI engine version. The main reason for the speed limitation is the vibration caused by the inertia force arising from the heavy elongated piston, which increases with the square of the engine speed.

In SI engines with port injection system, fuel behavior both in the intake port and in the cylinder has significant influence on the transient A/F characteristics and HC emissions [1]. Therefore, to improve the engine performance, it is very important to understand fuel behavior in the intake port and in the cylinder [2, 3]. This paper describes the following three unique methods to analyze fuel behavior in port injected SI engines and some test results. (1) Observation of fuel behavior in the intake port, using a transparent intake air tube and a strobe synchronized TV-photographic system. (2) Observation of fuel behavior in the cylinder, using a glass cylinder and fluorescent fuel. (3) Measurement of fuel wall wetting in the intake port and in the cylinder, using the engine with electronically controlled hydraulically driven in-take/exhaust valves.

Transmission error is the main cause of gear noise in automobile transmissions, and recently can be estimated by numerical analysis [1]. First, in this report, we establish the accurate numerical analysis of transmission error by using FE analysis and Hertz's contact analysis of gear tooth stiffness. Secondly, on the basis of the established numerical analysis, we develop a new tooth flank form to reduce transmission error. The new tooth flank form aims to ensure the coincidence of meshing stiffness at all meshing positions. Finally, a validation test using an experimental prototype is performed, and we confirm that the estimated effect by the new tooth flank form has been obtained.

To meet the requirements for higher horsepower and torque as well as lower fuel consumption and emissions, we have developed a new “Intelligent Variable Valve Timing (VV-i)” system. It gives continuously variable intake cam phasing by up to 60 degrees crank angle (CA) . This system not only increases WOT output by optimizing intake valve closing timing but also reduces fuel consumption and NOx/ HC emissions under part load by increasing intake and exhaust valve overlap on 4 stroke Spark Ignited engines. VVT-i has been applied to optimize a new 3-liter inline 6 engine for higher torque and at the same time better fuel economy with continuous and wide-range cam phasing.

A laboratory scale simulation test method was developed to evaluate deterioration of radial lip seals of fluoroelastomer (FKM) compounds for engine crankshafts. The investigation of the collected radial lip seals of FKM compounds from the field with service up to 450,000km indicated that the only symptom of deterioration is a decrease of lip interference. This deterioration was not duplicated under conventional test conditions using an oil seal test machine because sludge build up at the seal lip caused oil leakage. However, revised test conditions make it possible to duplicate the deterioration experienced in the field. An immersion test using a radial lip seal assembled with the mating shaft was newly developed. This test method was found to be useful to evaluate deterioration of radial lip seals using FKM compounds. Oil additives affect the deterioration of lip seal materials significantly. Therefore, immersion tests of four different oils were conducted to evaluate this effect.

A new test machine has been developed which can evaluate vibration due to stick-slip using an actual full-scale clutch pack. Using this machine, a static breakaway friction coefficient measurement test method and a stick-slip test method have been established. Both methods have been shown to provide results which correlate with the results from both a full-scale assembly test and a vehicle shudder evaluation test. The evaluation of the frictional properties of commercial oils using these test methods showed that the static breakaway friction coefficient and the stick-slip properties have generally contradictory performance to each other for automatic transmission. The study of the frictional properties for typical additives and an analysis of the surface of the steel plates with ESCA (Electron Spectroscopy for Chemical Analysis) showed that the frictional properties are significantly affected by the additives adsorbed on the clutch plate sliding surface.

To avoid knocking phenomena, a special crank mechanism for gasoline engine that allowed the piston to move rapidly near TDC (Top Dead Center) was developed and experimentally demonstrated in the previous study. As a result, knocking was successfully mitigated and indicated thermal efficiency was improved [1],[2],[3],[4]. However, performance of the proposed system was evaluated at only limited operating conditions. In the present study, to investigate the effect of piston movement near TDC on combustion characteristics and indicated thermal efficiency and to clarify the knock mitigation mechanism of the proposed method, experimental studies were carried out using a single cylinder engine with a compression ratio of 13.7 at various engine speeds and loads. The special crank mechanism, which allows piston to move rapidly near TDC developed in the previous study, was applied to the test engine with some modification of tooling accuracy.

The characteristics of exhausted smoke of a methanol DI diesel engine which is ignited by diesel fuel are investigated to clarify the soot formation process. At this engine, very little smoke is exhausted when diesel fuel is kept below a certain amount, so soot and smoke emitting characteristics are studied under the various diesel fuel amounts. By analyzing microstructure of soot, it is found that the soot emitted from the methanol diesel engine is composed of inner core and outer shell, similar to that of the conventional diesel engines. From more detailed qualitative analysis, the calcium percentage from the lubricating oil in outer shell is much higher than that of the conventional diesel engines. In consideration of soot characteristics, spray structure and combustion characteristics, the soot formation process of the methanol diesel engine was clarified.

A new stratified charge system has been developed for direct injection gasoline engines. The special feature of this system is employment of a thin fan-shaped fuel spray formed by a slit nozzle and a shell-shaped piston cavity. This system, basically classified into the wall-guided mixture preparation concept that leads air/fuel mixture to the spark plug periphery by means of spray penetration and piston cavity configuration without an extra intake air flow controlling system, obtained wide engine operating area with stratified combustion and high output performance. This report presents the characteristics of stratified mixture formation and combustion, especially the important factor for achieving stable stratified combustion in the high-speed region, which have been clarified through analytical studies.