- What is internal combustion engine?
It is a heat engine where the combustion of air and fuels take place inside the cylinder and generate torque used to move automobile.
- Who invented the internal combustion engine?
The Man behind this invention is JEAN JOSEPH ETIENNE LENOIR .Lenoir was born in mussy-la-ville, a part of Belgium in 1832.At the age of 28 he moved to France where he started to show keen interested toward electroplating. His interest towards electroplating and doing analysis of working of electricity led Lenoir to create the first single-cylinder two stroke engine.
Classification of Internal Combustion engine:-
- According to design
- Reciprocating Engine (use in automobiles)
- Rotary Engine (use in turbine)
- According to type of Fuel
- Petrol engine (Gasoline engine)
- Diesel engine
- Gas turbine(LPG,CNG)
- Alcohol engine (ethanol ,methanol etc)
- of stroke per cycle
- Two stroke
- Four stroke
- According to working cycle
- Otto cycle engine( constant volume )
- Diesel cycle engine(constant pressure)
- Dual combustion cycle engine(semi diesel cycle )
- According to No. Of cylinder
- Single cylinder
- Multi cylinder
- According to air –fuel mixture supply
- Carburetted type( fuel supply using carburettor)
- Injection type (fuel injection into cylinder just before ignition)
- Method of cooling
- Air cooled
- Water cooled
- Speed of engine
- High speed
- Medium speed
- Low speed
- Cylinder arrangement
- Piston engine
- Governing method
- Hit and miss governed engine
- Quantitatively governed engines
- Qualitatively governed engine
- For land transportation
- Marine engine for propulsion of ships
- Aircraft engine
- Industrial engine
- Prime movers for electrical generator
Check what the main components of IC engine are:-
Cylinder: its very important part of piston , in which piston move or reciprocate .It should have high strength and must be capable to handle pressure above bar and temperature and above 2000.
The ordinary engine which we are using now made of a cast iron and heavy duty engines are made of steel alloy or aluminium alloy. Multicylinder engines are cast in one block known as cylinder block.
Cylinder head: Its is top end of cylinder where inlet and exhaust valve ,spark plug or injectors are mounted. To make air tight joint a copper or asbestos gasket is provided between the engine cylinder and cylinder head.
Piston: piston transmits the force exerted by burning of fuel and air mixture to the connecting rod. Pistons are usually made of aluminium alloy which has good heat conducting property and greater strength at higher temperature.
Piston rings: This rings are located between the piston and cylinder and made of steel alloys which retain elastic properties even at very high temperature.
Types of piston rings :- 1) Compression Rings
2) Oil Rings
Compression ring is upper ring of the piston which provides air tight seal to prevent leakages of the burnt gases into the lower portion.
Oil ring is lower ring which provides effective seal to prevent leakage of the oil into the engine cylinder.
Connecting rod: Main function of connecting rod is to convert reciprocating motion of piston into circular motion of the crank shaft. The smaller end of the connecting rod is connected with the piston by gudgeon pin and bigger end of the connecting rod is connected with the crank with crank pin. Connecting rod are made of steel alloy or aluminium alloys.
Crankshaft: Main function of crankshaft is to converts the reciprocating motion of the piston into the rotary motion with the help of connecting rod. The special steel alloys are used for the manufacturing of the crankshaft. It consists of eccentric portion called crank.
Crank case: it is metal housing around the cylinder and crankshaft of the IC engine and also serve as a sump for the lubricating oil.
Flywheel: Main function of flywheels is to store rotational energy and it is mounted on the crankshaft and it maintain speed of crankshaft constant. It store excess energy during the power stroke, which is returned during other stroke.
Different terminology used in IC engine:-
- Cylinder bore (D): The nominal inside diameter of the engine cylinder.
- Piston area (A): The area of circle of diameter equal to the cylinder bore.
- Stroke (L): The maximum distance travelled by the piston in the cylinder in one direction is known as stroke.
- Dead centre: The position of the working piston and the moving parts which are mechanically connected to it at the moment when the direction of the piston motion is reversed (at either end point of the stroke).
(a) Bottom dead centre (BDC): The extreme position of the piston at the bottom of the cylinder of the vertical engine.
(b) Top dead centre (TDC): The extreme position of the piston at the top of the cylinder of the vertical engine.
- Displacement volume or swept volume (Vs): The nominal volume generated by the working piston when travelling from the one dead centre to next one and given as,
Vs=A × L
- Clearance volume (Vc): The volume contain in the cylinder above the top of the piston, when the piston is at top dead centre.
- Cylinder volume (V): Total volume of the cylinder.
V= Vs + Vc
- Compression ratio (r): Is a ratio of the volume when the piston is at bottom dead centre to the volume when the piston is at top dead centre.
Compression ration varies from 5:1 to 10:1 for petrol engine and from 12:1 to 22:1 for diesel engines.
Compression ration =
What is SI engine:-
SI engine is spark ignition engine , in which air-fuel mixture is ignite using spark plug.
What is CI engine:-
CI engine is compression ignition engine, in which fuel is injected in the form of spray and ignition caused by the high temperature of the air in the cylinder due to mechanical compression.
Comparison Between SI and CI engine:-
|Sr.No||SI Engine||CI Engine|
|1||It work on otto cycle and combustion of fuel take place at constant volume (V=Constant).||It work on diesel cycle and combustion of fuel take place at constant pressure (P=constant).|
|2||It suck mixture of petrol and air during suction stroke .||It suck air during suction stroke.|
|3||Carburettor is used to mix air and fuel in required proportion and supply to engine during suction stroke.||Injector is used to inject the fuel at the end of combustion stroke.|
|4||Fuel –air mixture ignite using spark plug.||Fuel is injected in the form of fine spray. The temperature of the compressed air is sufficiently high to ignite the fuel.|
|5||Compression ratio is between 6 to 10.||Compression ratio is between 15 to 25.|
|6||Starting of engine is easy due to low compression ratio.||Starting of engine is difficult due to high compression ratio.|
|7||Running cost is high .||Running cost is low.|
|8||Thermal efficiency is about 26%.||Thermal efficiency is about 40%.|
|9||This are high speed engine.||This are low speed engine.|
|10||Generally used in light duty vehicle such as scooter, motorcycle, and car . This are also used in aeroplanes .||Generally used in heavy duty vehicles like truck, buses and earth moving machine.|
Comparison between Two stroke vs Four stroke engine:-
|Sr.No.||Two stroke engine||Four stroke engine|
|1||One revolution of crankshaft and two stroke of the piston||Two revolution of crankshaft and four stroke of the piston|
|2||One power stroke in each revolution of crankshaft||One power stroke in two revolution of crankshaft|
|3||Flywheel is lighter (uniform turning movement)||Flywheel is heavy( non-uniform turning movement)|
|4||Power produce is twice the 4 stroke engine||Power produce is less|
|5||Light and compact||Heavy and bulky|
|6||High cooling is required||Lesser cooling is required|
|7||High Rate of wear and tear||Low rate of wear and tear|
|8||Initial cost is low||High initial cost|
|9||Volumetric efficiency is low due to lesser time of induction||Volumetric efficiency is high due to high time of induction|
|10||Thermal efficiency is low||Thermal efficiency is high|
|11||It used where low cost, compactness and light weight are important||It used where efficiency is imporatant|