Final answer:
An Atkinson-cycle engine is designed with a short compression stroke and a long power stroke to increase efficiency, extracting more energy from fuel.
Step-by-step explanation:
A Atkinson-cycle engine is designed with a shorter compression stroke and a longer power stroke to increase efficiency. This mechanism allows the engine to expand the combustible mixture to a greater volume than it was compressed, hence extracting more mechanical energy from a given amount of fuel compared to traditional engines. In the four-stroke internal combustion gasoline engine, the power stroke, where the air-fuel mixture is ignited and pushes the piston down, is designed to maximize the work output from the expanding gases. For diesel engines, similar principles apply where only air is drawn in during the intake stroke and then compressed to a point where fuel is injected and spontaneously ignites.