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opposed-piston engine
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Diagram showing four types of gasoline engines: an opposed-piston engine with pistons facing each other, a Wankel rotary engine with a triangular rotor, an in-line engine with pistons arranged vertically, and a V-type (V-8) engine with pistons set in a V shape. Arrows indicate the direction of motion in each engine.
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opposed-piston engine

Also known as: opposed-cylinder engine
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Diagram showing four types of gasoline engines: an opposed-piston engine with pistons facing each other, a Wankel rotary engine with a triangular rotor, an in-line engine with pistons arranged vertically, and a V-type (V-8) engine with pistons set in a V shape. Arrows indicate the direction of motion in each engine.
gasoline engines Gasoline engine types include (A) opposed-piston engines, (B) Wankel rotary engines, (C) in-line engines, and (D) V-8 engines.

An opposed-piston engine is a type of internal combustion engine where two pistons move in opposite directions within the same cylinder. This design offers excellent balance because the reciprocating masses move against each other. Unlike other two-stroke engines, opposed-piston designs eliminate the need for poppet valves, using ports in the cylinder wall instead, which are covered and uncovered by the pistons. This configuration contributes to efficient scavenging, where exhaust gases are expelled and a fresh fuel mixture is introduced.1

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5 Britannica Sources
  1. gasoline engine - Opposed-piston engines
  2. piston and cylinder
  3. piston engine
  4. gasoline engine - Pistons
  5. gasoline engine - Two-stroke cycle

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