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A new compact five-speed automatic transmission (A650E) has been developed for front engine rear wheel drive cars. The development of this transmission has been aimed at improving fuel consumption, power performance, engine noise reduction during highway cruising and smooth acceleration by employing a wide range of gearing and close gear ratios. Generally a five-speed automatic transmission is larger than a four-speed, because of additional friction elements and gears. This can result in a change in the floor panel of the car body. However, by removing a one-way clutch for second gear and employing a unique gear-train layout, this transmission has the same circumference and length as the conventional four-speed automatic transmission (A340E)(1).1 In order to reduce first or second gear noise, gear specification and supporting structures of planetary gears have been optimized by FEM analysis.

TOYOTA has developed the world's first eight-speed automatic transmission (AA80E) for front-engine, rear-drive passenger cars. The AA80E developed for high-torque engines raises the level of power performance and fuel efficiency. To meet the size requirements needed for mounting in a passenger car application, an 8-speed geartrain, torque converter, transmission case and hydraulic control device were all newly-developed. Furthermore, the AA80E has benefited from technical developments to achieve an extremely high level of quietness and shifting performance. In this paper, the details of the AA80E are introduced.

A new five-speed automatic transaxle, U150E, has been developed for FWD passenger cars. The goals of the development of this transaxle are fuel economy improvement, better acceleration performance, and a smoother shift feel. U150E achieved its targets by adopting a wide gearing range and using hydraulic control system design based on various simulations. This paper describes the major features, performance of this automatic transaxle, and technical points of the development.

Improvement of warming performance is required for engine cooling system, because such improvement has an important role for lower emissions. However, the cooling performance and the warming performance of engine are related to the transactions. To improve such trade-off relation between the two performances, oil-cooled system was developed which components are simpler than conventional water-cooled system with a single cylinder, 339cc engine. The oil-cooled system has an “oil jacket” that closely encircles the combustion chamber to cool the cylinder head and cylinder sufficiently. This system adopts the engine lubrication oil to cool combustion chamber, thus the average temperature of the combustion chamber is higher than usual water-cooled engine that enables better warming performance.

An oil-cooled engine has been developing to achieve better warm-up performance. The oil-cooled engine has an oil jacket that pass through around the exhaust port and the cylinder liner. Fins were installed inside the oil jacket to enhance cooling performance. The result of a bench test shows that the fins enhance the cooling performance with slight loss of warm-up performance. The aim of this study is to clarify effects of the fins. This study conducted two simulations. One is a cooling simulation that was conducted to clarify the reason why the fins enhanced the cooling performance. The other is a warm-up simulation that was conducted to clarify the reason why the fins almost maintained the warm-up performance. The cooling simulation was conducted by steady flow simulation. It simulated a full-load operation of the bench test. It compared converged temperature between the engines with/without the fins. The warm-up simulation was conducted by unsteady flow simulation.

The aim of this study is to analyze the emission improvement in the oil-cooled engine by use of internal cylinder gas pressure measurement and 3D simulation of thermal flow and combustion. In the previous study, two test engines were designed to evaluate the benefits of the oil-cooled engine. One was an oil-cooled, and the other was a water-cooled engine. Both engines were single cylinder engines with SOHC valve-train systems. The hardware specifications of both engines were exactly the same except for their cooling systems in order to clarify how the difference in engine cooling system affects their cooling performance, warm-up performance and emission performance.