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During next decade, automotive engineers will take up unprecedented challenges to meet a variety of technical demands on passenger cars. While performance, refinement and reliability will continue to be major technical goals of passenger cars, reducing their impact on the environment not only in urban areas but also on the global basis will become an increasingly urgent issue. In addition, the need for energy and resources saving will necessitate development of more fuel efficient cars, exploitation of alternative energy and recycled materials. In this paper, the authors will review various alternative engines as candidates to satisfy the above demands. The authors will also discuss various alternative transportation energy sources such as alcoholic fuels, natural gas, hydrogen and electricity. Finally the trends of future passenger car engine design will be discussed.

A new combustion system - called MCA-JET- has been developed to improve combustion under the low speed, low load conditions typical of urban driving. Engines with this new system incorporate a special “jet valve”, in addition to the inlet and exhaust valves of the conventional combustion chamber, which directs air or a super-lean mixture towards the spark plug, and induces a strong swirling flow in the cylinder. This swirl persists during the compression and expansion processes, moves the mixture spirally and helps the flame to propagate. As a result, the combustion of lean mixtures, including those with exhaust gas recirculation, can be carried out rapidly and thus the fuel economy improved.

Subcompact cars generally use 4-cylinder engines, because of their advantages over 6-cylinder or 8-cylinder engines in production cost, engine size, weight, combustion efficiency, emission control, etc. The 4-cylinder engine, however, has an inherent shortcoming of second order vibration in the vertical and rolling directions, originating from the reciprocating masses and explosions in the engine. A new in-line 4-cylinder engine with its vibration reduced to a level comparable to the 6-cylinder engine or rotary engine has been recently developed while retaining the advantages mentioned above. The engine incorporates a unique balancing system, which reduces the booming to a minimum in the vehicle passenger compartment.

This paper outlines the design features of the 4-cyl, overhead camshaft 1.6-liter Dodge Colt engine together with four other single and double overhead camshaft engines in the same family. These engines have been developed for high performance with a compact size and reduced weight. The Dodge Colt engine, in particular, has been designed to be in compliance with stringent 1972 United States emissions standards. Emission controls achieved with this engine, such as improved combustion chamber design of small surface/volume ratio and various control systems, are described in some detail.

The paper describes the designing points and the research results obtained during the development of 2 liter and 3 liter capacity diesel engines, and also reviews the development of small diesel engines. It comoares the diesel engine with the same bore and stroke gasoline engine, simultaneously developed, on the bases of their performances and structures.