The combustion engine came into existence about two centuries ago and has undergone constant refinements since then. Despite lacking quite a bit in efficiency and with inherent pollution problems, combustion engines are here to stay due to their adaptability and lack of a cost effective alternative. There is no denying the fact that combustion engines changed lives of man-kind as it evolved over time.
Combustion engines may be broadly classified into two types:
The internal combustion engine can be further classified into various types based on fuel, strokes per cycle, cycle type, number of cylinders, ignition, lubrication type, cooling, valve arrangement, cylinder positioning and pressure boost type to name only a few.
Steam engines were the earliest type of external combustion engine. Other engines that used more or less the same principle, i.e. external heating of fluid, are the rankine cycle engine, Stirling engine, trochilic engine, naphtha engine and nuclear power stations.
Two Stroke Combustion Engine
Four Stroke Combustion Engine
External Combustion Engine
Internal combustion engine has overtaken external combustion steam engines for use in ships and heavy locomotives as well as cars, motorcycles and power tools as well as equipments.
Though advanced, today’s combustion engines have a conversion efficiency of only 30% with the rest of the energy being lost as heat and as an unburnt fuel.