Power Stroke |
One power stroke per two crankshaft revolutions |
One power stroke per crankshaft revolution |
Flywheel and Balance |
Requires heavier flywheel; less balanced |
Requires lighter flywheel; more balanced |
Engine Weight |
Heavier engine |
Lighter engine |
Design Complexity |
More complex due to valves |
Simpler, no valves (uses ports) |
Cost |
Higher cost |
Lower cost |
Efficiency |
Less mechanical efficiency due to more friction |
Higher mechanical efficiency, fewer moving parts |
Lubrication System |
Complicated system; consumes less oil |
Simple system; consumes more oil |
Usage |
Used in cars, buses, and trucks |
Used in mopeds, scooters, and motorcycles |