Advanced military diesel engine

A modified engine cycle based on the early intake valve closing of the Miller or the Adkinson cycle is proposed to meet the needs of the future Military Advanced Diesel Engine. The concpet involves the principle of short, effective compression with long expansion ratio to provide high brake thermal efficiency. This concept is executed by a variable timing rotary valve placed before the standard intake poppet valve. Easy starting can be had by reverting the rotary valve in phase with the conventional intake valve timing. The rotary valve and the variable timing mechanism are the only additional equipment needed to fulfill the requirements of this engine cycle. Thus, a low cost, simple and reliable high output engine can be achieved. The concept can also be used on a gasoline reciprocating engine. Since the effective compression ratio is low, the compression temperature is lower, resulting in an ideal natural gas engine, or low NOx emission engine as well. The modified Miller cycle engine can be insulated with proper ceramic coating and low specific heat rejection of 12 but/bhp-hr can be achieved. High temperature components and tribology will be incorporated in the cylinder liner, piston ring and piston area.