Introduction to Internal Combustion Engines

An internal combustion engine (ICE) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is applied typically to pistons, turbine blades, rotor or a nozzle. This force moves the component over a distance, transforming chemical energy into useful work. This replaced the external combustion engine for applications where weight or size of the engine is important.

Based on the experimental results the combustion in SI engines takes place in three stages as follows:

1. Period of ignition Lag Or preparation phase.

2. Flame propagation phase.

3. after burning or flame termination phase.

A valve timing diagram is a graphical representation of the opening and closing of the intake and exhaust valve of the engine, The opening and closing of the valves of the engine depend upon the movement of piston from TDC to BDC, This relation between piston and valves is controlled by setting a graphical representation between these two, which is known as valve timing diagram

Knocking, in an internal-combustion engine, sharp sounds caused by premature combustion of part of the compressed air-fuel mixture in the cylinder. In a properly functioning engine, the charge burns with the flame front progressing smoothly from the point of ignition across the combustion chamber

Emission control system, in automobiles, means employed to limit the discharge of noxious gases from the internal-combustion engine and other components. ... There are three main sources of these gases: the engine exhaust, the crankcase, and the fuel tank and carburetor.