Explain heat engines, state factors of engine operation, and list differences between 2 and 4 cycle engines.

What is an heat engine? (2mks) A heat engine is a device that converts thermal energy (heat) into mechanical energy (work) by exploiting a temperature difference between a heat source and a heat sink.

State three factors of engine operation and 4 cycle engine operation. (3mks)

• Three factors of engine operation: Fuel-air mixture ratio, ignition timing, and compression ratio.
• 4-cycle engine operation: A 4-cycle engine completes one power cycle in four piston strokes (intake, compression, power, exhaust) and two crankshaft revolutions.

List 2 major difference between 2 and 4 cycle engine when the piston is moving up. (2mks)

• In a 2-cycle engine, the upward stroke involves compression of the fuel-air mixture and closing of the transfer port.
• In a 4-cycle engine, the upward stroke involves either compression (with both valves closed) or exhaust (