Abstract

Eighty percent of energy used world-wide begins as heat from fossil fuels which are rapidly being depleted. Heat engines that use much of this energy must be more efficient in the future. An Atkinson-Diesel (A-D) cycle is proposed. The A-D engine will cause less environmental harm while also using less energy. It combines three key elements—(1) an Atkinson-Diesel cycle with high intrinsic thermodynamic efficiency, (2) two-stroke operation to minimize losses, and (3) a long-stroke, high-compression geometry. The efficiency of the ideal Atkinson-Diesel cycle is presented and shown to correlate well with a modified air-standard analysis for a compact, high-compression A-D engine. The engine's compression ratio of 35 enables low emissions through a combination of lean-burn, exhaust retention, and fuel selection. The A-D engine can use many kinds of clean-burning and renewable fuels and is calculated to have a brake efficiency near 60%. Conversion to this engine has the potential to save 17 million barrels of oil per day, or 20% of world oil consumption.