Which type of engine typically uses a spark plug for ignition?

• A. Diesel engine
• B. Rotary engine
• C. Gasoline engine
• D. Hybrid engine

Answer: (C)

The gasoline engine typically uses a spark plug for ignition because it operates on a four-stroke cycle that requires an external ignition source to ignite the air-fuel mixture in the combustion chamber. The spark plug generates a small spark at precisely the right moment in the compression stroke, initiating the combustion process that powers the engine. This is essential for gasoline engines since they rely on a mixture of air and gasoline, which needs the spark to ignite.

In contrast, diesel engines use compression ignition, where the air is compressed to such a high degree that it ignites the fuel upon injection. Rotary engines, which are a type of internal combustion engine, function similarly to gasoline engines but typically employ ignition methods that are specific to their design. A hybrid engine, which combines both gasoline and electric components, primarily relies on the combustion engine's characteristics; therefore, it may utilize a spark plug for its gasoline component. However, the fundamental mechanism of ignition through a spark plug is most directly characteristic of gasoline engines.