🔍 Key Concepts

• Basic engine motion types: reciprocating vs rotary • Where the fuel actually burns: internal vs external combustion • How diesel fuel is ignited compared to gasoline engines

💭 Think About

• Ask yourself: In a diesel, do parts move back-and-forth, rotate, or both — and what is the primary motion type used to describe the engine? • Does a diesel burn its fuel inside the cylinder where the piston moves, or somewhere outside and then transfer heat in? • What specifically causes ignition in a diesel: a spark plug, or very high compression and temperature of the air-fuel mixture?

✅ Before You Answer

• Identify whether a diesel is classified as reciprocating or rotary for exam purposes. • Decide if a diesel is an internal or external combustion engine based on where combustion takes place. • Confirm whether diesel ignition relies on heat from compression or electric spark.