![working principle of ic engines working principle of ic engines](https://upload.wikimedia.org/wikipedia/commons/4/47/Four_stroke_engine_diagram.jpg)
They are also used in many small utility applications. They power cars, trucks, trains and most marine vessels. Reciprocating piston engines are perhaps the most common form of internal combustion engine known. In internal combustion (IC) engines, the working fluid consists of air, a fuel-air mixture or the products of combustion of the fuel-air mixture itself. In a rotary engine, the working fluid spins a rotor that is connected to the output shaft. The linear motion is then commonly converted to rotary motion through a crank-slider (connecting rod/crankshaft) mechanism. In reciprocating engines, the working fluid is used to move a piston in a linear fashion. They can also be classified as either reciprocating or rotary. This heat is used to raise the temperature and pressure of a working fluid that is then used to perform useful work. Heat engines are energy conversion machines-they convert chemical energy in a fuel into work by combusting the fuel in air to produce heat. Basic design and performance parameters in internal combustion engines include compression ratio, swept volume, clearance volume, power output, indicated power, thermal efficiency, indicated mean effective pressure, brake mean effective pressure, specific fuel consumption, and more. The combustion process can be theoretically modeled by applying laws of mass and energy conservation to the processes in the engine cylinder. A number of other engine classifications are possible, based on engine mobility, application, fuel, configuration, and other design parameters. In each case, the engine may be equipped with either a spark-ignited (SI) or a compression-ignited (CI) combustion system.
![working principle of ic engines working principle of ic engines](https://cdn.britannica.com/72/93572-004-26C16785/engine-strokes-combustion-intake-compression-exhaust-stroke.jpg)
Ideally the efficiency of 4-stroke engine should be double of 2-stroke engine, but in actuality it is never so.Reciprocating internal combustion engines-a subclass of heat engines-can be operated in the four- and two-stroke cycles. Since the 4-stroke engines produce two rotations while 2-stroke engine produces single rotation each time the fuel is burnt, the efficiency of 4-stroke engines is greater than in 2-stroke engines. The stroke is the distance traveled by the piston inside the cylinder it is usually equal to the length of the cylinder. That means each time the fuel is burnt there are two rotations of the wheels of the vehicle. In the case of four-stroke engines, the fuel is burnt for every four strokes of the piston inside the cylinder. This means for every single rotation of the wheel the fuel is burnt. In the case of the two stroke engine, for every two strokes of the piston inside the cylinder the fuel is burnt.
![working principle of ic engines working principle of ic engines](https://img.yumpu.com/62845563/1/500x640/lecture-3-ic-engine.jpg)
The SI and CI engines are either two stroke or four stroke engines. In CI engines the fuel used is diesel hence they are also called Diesel engines. The fuel is compressed to high pressures and it starts burning, hence these engines are called compression ignition engines. In the case of CI engines, burning of the fuel occurs because of the high pressure exerted on the fuel. In these engines the fuel used is petrol or gasoline, hence SI engines are also known as Petrol or Gasoline Engines. Due to this fact they are called spark ignition engines. In SI engines the burning of fuel occurs by a spark generated by the spark plug located in the cylinder head of engine. It is this reason that even the IC engines are broadly classified into two types: SI engines and CI engines. Since reciprocating engines are the most widely used engines, they have become synonymous with the name IC engines. Reciprocating engines are classified into two types: spark ignition (SI) engines and compression ignition (CI) engines. They are the most widely used type of engine. In automobiles, reciprocating engines are used. The reciprocating motion of the piston is converted into the rotary motion of the vehicle’s wheels. In the case of the reciprocating engines, a piston reciprocates within a cylinder. In rotary engines, a rotor rotates inside the engine to produce power. There are two types of IC engines: rotary and reciprocating engines. After combustion of fuel, much heat energy is generated, this is converted into mechanical energy. Internal Combustion Engines, more popularly known as IC engines, are the ones in which the combustion of fuel takes place inside the engine block itself.