Differences between a Steam engine and a Petrol engine are:
Steam engine (External combustion engine)
1. Steam engine is an external combustion engine, in which the fuel (coal) is burned in the fire-box of the boiler, outside the cylinder.
2. The propelling power in a steam engine is the steam under pressure.
3. A steam engine is big, heavy, and occupies a lot of space.
4. A steam engine takes a long time to start.
5. The efficiency of a steam engine is low. It is about 20%.
Petrol engine (Internal combustion engine)
1. Petrol engine is an internal combustion engine, in which the fuel (petrol) is burned inside the cylinder of the engine.
2. The propelling power in a petrol engine is the expansive force of the products of combustion of petrol.
3. A petrol engine is small, light, and occupies a small space.
4. A petrol engine can be started at a moment’s notice.
5. The efficiency of a petrol engine is much higher. It is about 40%.