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This paper describes a study which was carried out to determine the feasibility of the diesel as a light duty power plant for American use. As a result of a literature survey and a specific configuration study, nine 96 kW diesel power plants were examined in detail. Further examination of the diesel power plants indicated that only the direct injection four-stroke configurations could meet the primary emission targets using current technology. It was concluded, however, that the diesel engine could provide a viable power plant for light duty vehicles and that considerable improvements in fuel consumption and overall running costs could be obtained.

A computer program -- LeRC3D.Wankel -- was developed to study the flow, spray, and spray combustion in the combustion chambers of Wankel rotary engines. LeRC3D. Wankel is based on an Eulerian-Lagrangian formulation. The gas phase was modelled by an Eulerian approach using the density-weighted, ensemble-averaged conservation equations of mass, momentum (full compressible Navier-Stokes), total energy, and species, closed by a low Reynolds number k-ε turbulence model. The liquid phase, made up of fuel droplets, was modelled by using a Lagrangian approach in which droplet groups are tracked in time. The combustion process which takes place after fuel droplets evaporate and mix with the surrounding air was assumed to be chemical kinetics controlled via a two-step global mechanism. This paper describes the formulation employed in the computer program as well as the essence of the numerical method used to generate solutions. Some computed solutions for the flow field are also presented.

The objectives of this project were to determine the acceptability of various types of stratified charge engines as potential power plants for light duty vehicles and motorcycles in America. The light duty vehicle considered was a four/five seat compact sedan with good acceleration capabilities and exhaust emissions below a primary target of 0.41 g/mile HC, 3.4 g/mile CO, 1.5 g/mile NOx. A secondary target of 0.41 g/mile HC, 3.4 g/mile CO and 0.4 g/mile NOx was also considered. A literature survey was undertaken, comparing stratified charge engines with examples of good conventional gasoline and diesel engines. While some stratified charge engines had exhaust emission or fuel economy advantages, there were always sacrifices in other areas. Eleven engines were configured, four of which were specifically directed towards the secondary emission targets. A method of rating the engines was derived, and the design concepts were compared with two gasoline engines by a jury panel.