The complete cycle of an engine requires four piston strokes: intake, compression power, and exhaust.

发动机完整的循环要求有活塞的四个冲程：进气、压缩、做功、排气。

youdao

The cycle of operation of the four-stoke engine begins with the piston at TDC and the intake valve open.

四冲程发动机的工作循环是以活塞在上止点、进气门打开为开始的。

youdao

Otto built the practical four-stroke internal combustion engine called the "Otto Cycle Engine, " and as soon as he had completed his engine, he built it into a motorcycle.

奥托制造了第一台实用的四冲程内燃机，叫做“奥托循环发动机”，并且当完成制造他的发动机后他就把发动机安装在摩托车上。

youdao

For years he had contemplated the inefficiencies of the traditional four-stroke Otto cycle engine (named for its 1876 developer, Nikolaus A. Otto).

FORBES: How To Get 50 MPG Out Of Your Gasoline Engine

When powered by gasoline, the C-MAX Energi uses the all-new 2.0-liter Atkinson-cycle four-cylinder engine - powerful and fuel efficient and among the most advanced non-turbocharged four-cylinder powertrains Ford has ever offered.

ENGADGET: Ford's 2013 C-Max Energi rolls out 95 MPGe, arrives later this fall

During the class, we walked through my Desire Engine framework, a four-step cycle that creates preferences and usage habits.

FORBES: How Investment Drives Engagement