Search Results

An advanced low heat rejection engine concept has been selected based on a trade-off between thermal insulating performance and available technology. The engine concept heat rejection performance is limited by available ring-liner tribology and requires cylinder liner cooling to control the piston top ring reversal temperature. This engine concept is composed of a titanium piston, headface plate and cylinder liner insert with thermal barrier coatings. Monolithic zirconia valve seat inserts, and thermal barrier coated valves and intake-exhaust ports complete the insulation package. The tribological system is composed of chrome oxide coated cylinder, M2 steel top piston ring, M2 steel valve guides, and an advanced polyol ester class lubricant.

This paper describes the progress on the Cummins-TARADCOM adiabatic turbocompound diesel engine development program. An adiabatic diesel engine system adaptable to the use of high performance ceramics which hopefully will enable higher operating temperatures, reduced heat loss, and turbo-charged exhaust energy recovery is presented. The engine operating environments as well as the thermal and mechanical loadings of the critical engine components are covered. Design criteria are presented and techniques leading to its fulfillment are shown. The present shortcomings of the high performance ceramic design in terms of meeting reliability and insulation targets are discussed, and the needs for composite designs are shown. A ceramic design methodology for an insulated engine component is described and some of the test results are shown. Other possible future improvements such as the minimum friction-unlubricated engine through the use of ceramics are also described.

Joint development of the adiabatic engine by Cummins Engine Company and the U. S. Army began with a feasibility analysis ten years ago. The effort was initially driven by the expectation of substantial performance improvement, a reduction in cooling system size, and several additional benefits. Program emphasis turned quickly to experimentation with the goal of demonstrating the feasibility of the adiabatic engine in working hardware. Several significant achievements were realized as have been reported earlier. Further development of the adiabatic engine is expected to be more evolutionary, paced by available technology in the areas of materials and tribology. Analysis capability necessary for insulated engine development has been found to be inadequate. Additional effort has gone into the development and validation of insulated engine analysis tools, both for cycle simulation and structural modeling.