- High Efficiency: Four-stroke petrol engines are relatively efficient in converting the energy stored in petrol into mechanical work. The complete combustion process allows for a higher expansion ratio and a more complete burning of the fuel, leading to better fuel efficiency.
- Smooth Operation: The four-stroke cycle, with its distinct phases of intake, compression, combustion, and exhaust, allows for smooth and consistent power delivery. The power strokes occur every other revolution, providing a more regular and balanced transfer of power.
- Less Noise and Vibration: Four-stroke engines generally produce less noise and vibrations compared to two-stroke engines. This is because the combustion process is more gradual, and the reciprocating masses are better balanced, resulting in quieter operation and reduced vibrations.
- Lower Emissions: Four-stroke engines produce fewer pollutants compared to two-stroke engines. Since the combustion takes place inside a closed chamber, there is better control over the fuel-air mixture and combustion process, resulting in reduced emissions of unburned hydrocarbons, carbon monoxide, and nitrogen oxides.
- Versatility: Four-stroke petrol engines are widely used in various applications, including cars, motorcycles, generators, lawnmowers, and other small engines. Their adaptability to different operating conditions and power requirements makes them versatile power sources.
Disadvantages of Four Stroke Petrol Engine:
- Complex Design: Compared to two-stroke engines, four-stroke engines have a more complex design. The presence of valves, camshafts, and other components required for the four-stroke cycle adds to the complexity and cost of manufacturing and maintenance.
- Higher Weight: Four-stroke engines are generally heavier than two-stroke engines of similar power output. The additional components and the requirement for a more robust cylinder head and block contribute to the increased weight.
- Lubrication Complexity: Four-stroke engines require a more intricate lubrication system compared to two-stroke engines. In a four-stroke engine, the oil needs to be circulated and pumped to various engine components, such as the crankshaft, camshaft, and valve train, to ensure proper lubrication.
- Susceptibility to Oil Contamination: Four-stroke engines are more susceptible to oil contamination compared to two-stroke engines. This is because the oil is not mixed with the fuel, as in two-stroke engines. As a result, there is a higher risk of particles and debris accumulating in the oil, leading to potential engine damage if the oil is not changed regularly.
