Research and Development Work to Optimize the Diesel Engine Design, to Operate at Greater than 42% Fuel Efficiency

LiquidPiston, Inc. is developing a new engine technology that is uniquely positioned to provide a solution to the Army’s objectives for an improved compression ignition engine. LPI’s new High Efficiency Hybrid Cycle (HEHC) engine will have the following predicted characteristics: Compression Ratio: Variable, from 15:1 to 28:1 Power: 650HP Efficiency, at all power loads: >42%, potentially as high as 50% Specific power:(half aluminum, half steel: 1.4 [hp/lb] Power Density : 80 [hp/cu ft] Fuel injection pressure: 30,000 [psi] Fuel efficiency of over 42% will be achieved by using a new thermodynamic cycle, which combines 1) high compression ratio (similar ot that of the Diesel cycle), 2) constant volume combustion (similar to the Otto cycle), and 3) full utilization of expansion (Atkinson or Miller cycles). The new engine’s compactness is due to a rotary piston design with lack of valves and a valve drive mechanism. Air-standard thermodynamic calculations have been completed to predict the engine’s efficiency.