BASIC ENGINE COMPONENTS
Although reciprocating internal combustion engines appear quite simple, they are highly complicated machines. Hundreds of components must perform their functions satisfactorily to produce output power. There are two kinds of engines viz., ignition and compression ignition engine.
let us now go through the vital engine components and the nomenclature related to an engine.
Engine components
An exploded engine view is shown in the figure . The main components of the engine and their functions are briefly described below.
1) Cylinder Block:
The cylinder block is the main supporting structure for the various components. The cylinder of a multicylinder engine is cast as a single unit, called a cylinder block. The cylinder head and cylinder block are provided with water jackets in the case of water cooling or with cooling fins in the case of air cooling. The cylinder head is mounted on a cylinder block. The cylinder head gasket is incorporated between the cylinder block and cylinder head. The cylinder head is held tight to the cylinder block by several bolts or studs. The bottom portion of the cylinder block is called a crankcase. A cover called crankcase which is machined and finished accurately to cylinder shape is called bore or face.
The cylinder block is the main supporting structure for the various components. The cylinder of a multicylinder engine is cast as a single unit, called a cylinder block. The cylinder head and cylinder block are provided with water jackets in the case of water cooling or with cooling fins in the case of air cooling. The cylinder head is mounted on a cylinder block. The cylinder head gasket is incorporated between the cylinder block and cylinder head. The cylinder head is held tight to the cylinder block by several bolts or studs. The bottom portion of the cylinder block is called a crankcase. A cover called crankcase which is machined and finished accurately to cylinder shape is called bore or face.
2) Cylinder:
It is the main part of the engine inside which the piston reciprocates to and fro. It should have a high strength to withstand high pressure above 50 bar and temperature above 2000 oC. The ordinary engine is made of cast iron and heavy-duty engines are made of steel alloys or aluminum alloys. In the multi-cylinder engine, the cylinders are cast in one block known as a cylinder block.
It is the main part of the engine inside which the piston reciprocates to and fro. It should have a high strength to withstand high pressure above 50 bar and temperature above 2000 oC. The ordinary engine is made of cast iron and heavy-duty engines are made of steel alloys or aluminum alloys. In the multi-cylinder engine, the cylinders are cast in one block known as a cylinder block.
3) Cylinder head:
The top end of the cylinder is covered by a cylinder head over which inlet and exhaust valve, spark plug, or injectors are mounted. A copper or asbestos gasket is provided between the engine cylinder and cylinder head to make an airtight joint.
The top end of the cylinder is covered by a cylinder head over which inlet and exhaust valve, spark plug, or injectors are mounted. A copper or asbestos gasket is provided between the engine cylinder and cylinder head to make an airtight joint.
4) Piston:
The piston of an engine is the first part to begin movement and to transmit power to the crankshaft as a result of the pressure and energy generated by the combustion of the fuel. It fits perfectly into the cylinder providing a gas-tight space with the piston rings and the lubricant. Usually made of aluminum alloy which has good heat-conducting property and greater strength at a higher temperature.
The piston of an engine is the first part to begin movement and to transmit power to the crankshaft as a result of the pressure and energy generated by the combustion of the fuel. It fits perfectly into the cylinder providing a gas-tight space with the piston rings and the lubricant. Usually made of aluminum alloy which has good heat-conducting property and greater strength at a higher temperature.
5) Piston rings:
These are housed in the circumferential grooves provided on the outer surface of the piston and made of steel alloys which retain elastic properties even at high temperature. 2 types of rings- compression and oil rings. The compression ring is an upper ring of the piston which provides an airtight seal to prevent leakage of the burnt gases into the lower portion. The oil ring is a lower ring that provides an effective seal to prevent leakage of the oil into the engine cylinder.
These are housed in the circumferential grooves provided on the outer surface of the piston and made of steel alloys which retain elastic properties even at high temperature. 2 types of rings- compression and oil rings. The compression ring is an upper ring of the piston which provides an airtight seal to prevent leakage of the burnt gases into the lower portion. The oil ring is a lower ring that provides an effective seal to prevent leakage of the oil into the engine cylinder.
6) Combustion Chamber:
The space enclosed in the upper part of the cylinder, by the cylinder head and the piston top during the combustion process, is called the combustion chamber. The combustion of fuel and the consequent release of thermal energy results in the building up of pressure in this part of the cylinder.
The space enclosed in the upper part of the cylinder, by the cylinder head and the piston top during the combustion process, is called the combustion chamber. The combustion of fuel and the consequent release of thermal energy results in the building up of pressure in this part of the cylinder.
7) Connecting rod:
It converts the reciprocating motion of the piston into circular motion of the crankshaft, in the working stroke. The smaller end of the connecting rod is connected with the piston by a gudgeon pin and the bigger end of the connecting rod is connected with the crank pin. The special steel alloys or aluminum alloys are used for the manufacture of connecting rods.
It converts the reciprocating motion of the piston into circular motion of the crankshaft, in the working stroke. The smaller end of the connecting rod is connected with the piston by a gudgeon pin and the bigger end of the connecting rod is connected with the crank pin. The special steel alloys or aluminum alloys are used for the manufacture of connecting rods.
8) Crankshaft:
It converts the reciprocating motion of the piston into the rotary motion with the help of connecting rod. The journals of the crankshaft are supported on main bearings, housed in the crankcase. Counter-weights and the flywheel bolted to the crankshaft help in the smooth running of the engine. The special steel alloys are used for the manufacturing of the crankshaft. It consists of an eccentric portion called a crank.
It converts the reciprocating motion of the piston into the rotary motion with the help of connecting rod. The journals of the crankshaft are supported on main bearings, housed in the crankcase. Counter-weights and the flywheel bolted to the crankshaft help in the smooth running of the engine. The special steel alloys are used for the manufacturing of the crankshaft. It consists of an eccentric portion called a crank.
9) Crankcase:
It houses the cylinder and crankshaft of the IC engine and also serves as a sump for the lubricating oil.
It houses the cylinder and crankshaft of the IC engine and also serves as a sump for the lubricating oil.
10) Flywheel:
This is usually made of cast iron. It is a big wheel mounted on the crankshaft, whose function is to maintain its speed constant. It is done by storing excess energy during the power stroke, which is returned during other strokes.
This is usually made of cast iron. It is a big wheel mounted on the crankshaft, whose function is to maintain its speed constant. It is done by storing excess energy during the power stroke, which is returned during other strokes.
11) Engine Bearings:
The crankshaft and camshaft are supported on anti-friction bearings. These bearings must be capable of standing at high speed, heavy load, and high temperatures. Normally, cadmium, silver, or copper lead is coated on the steel back to give the above characteristics. For single cylinder vertical/horizontal engines, the present trend is to use ball bearings in place of main bearings of the thin shell type.
The crankshaft and camshaft are supported on anti-friction bearings. These bearings must be capable of standing at high speed, heavy load, and high temperatures. Normally, cadmium, silver, or copper lead is coated on the steel back to give the above characteristics. For single cylinder vertical/horizontal engines, the present trend is to use ball bearings in place of main bearings of the thin shell type.
12) Inlet Manifold:
The pipe which connects the intake system to the inlet valve of the engine and through which air or air-fuel mixture is drawn into the cylinder is called the inlet manifold.
The pipe which connects the intake system to the inlet valve of the engine and through which air or air-fuel mixture is drawn into the cylinder is called the inlet manifold.
13) Exhaust Manifold:
The pipe which connects the exhaust system to the exhaust valve of the engine and through which the products of combustion escape into the atmosphere is called the exhaust manifold.
The pipe which connects the exhaust system to the exhaust valve of the engine and through which the products of combustion escape into the atmosphere is called the exhaust manifold.
14) Valves:
To allow the air to enter into the cylinder or the exhaust, gases to escape from the cylinder, valves are provided, known as inlet and exhaust valves respectively. The valves are mounted either on the cylinder head or the cylinder block.
To allow the air to enter into the cylinder or the exhaust, gases to escape from the cylinder, valves are provided, known as inlet and exhaust valves respectively. The valves are mounted either on the cylinder head or the cylinder block.
15) Camshaft:
The valves are operated by the action of the camshaft, which has separate cams for the inlet, and exhaust valves. The cam lifts the valve against the pressure of the spring and as soon as it changes position the spring closes the valve. The cam gets to drive through either the gear or sprocket and chain system from the crankshaft. It rotates at half the speed of the camshaft.
The valves are operated by the action of the camshaft, which has separate cams for the inlet, and exhaust valves. The cam lifts the valve against the pressure of the spring and as soon as it changes position the spring closes the valve. The cam gets to drive through either the gear or sprocket and chain system from the crankshaft. It rotates at half the speed of the camshaft.
16) Spark Plug:
It is a component to initiate the combustion process in Spark-Ignition (SI) engines and is usually located on the cylinder head.
It is a component to initiate the combustion process in Spark-Ignition (SI) engines and is usually located on the cylinder head.
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