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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 particulate trap oxidizer system to reduce diesel particulate emissions has been developed. This system consists of a ceramic foam filter with an optimum volume, shape, and mesh number in terms of collection efficiency, pressure loss and particulate blow-off; a catalyst with a low activated-temperature for particulate incineration and with no sulfate formation during highway driving; and a regeneration system which prevents particulate overcollection during long-term continuous low-load/low-speed driving where it is difficult to achieve self-burning of particulates with a catalytic reaction. This paper describes the development of the particulate trap oxidizer system with these technologies and presents the results of practicability evaluations and 50,000-mile vehicle durability tests.

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.