BASIC
MECHANICAL AND CIVIL ENGINEERING
UNIT – I
THERMAL ENGINEERING
Classification of internal combustion engine
Working of two stroke petrol engine
Working of two stroke diesel engine
Working of four stroke petrol engine
Working of four stroke diesel engine
Classification of Boilers
Cochran boiler
Locomotive boiler
Classification of Power plants
Working of Thermal power plant
Working of Nuclear power plant
Working of Solar power plant
Working of Wind power plant
Working of Tidal power plant
Working of Geothermal power plant
,Internal Combustion engine – I C engine:
The internal combustion (IC) engine is a heat engine converts chemical energy of fuel
into shaft work. The combustion occurs inside a cylinder and the piston is pushed
down by combustion gas to revolve the crankshaft to perform work.
Classification of internal combustion engine:
I.C. engines can be classified as follows:
1. According to type of ignition of fuel
a. Spark Ignition b. Compression Ignition engine
2. According to type of fuel used
a. Petrol engine b. Diesel engine
3. According to number of strokes required for power
a. Two strokes b. Four strokes
4. According to Thermodynamic cycle
a. Otto cycle b. Diesel cycle
5. According to cylinder arrangement
a. Vertical b. Horizontal
6. According to number of cylinders
a. Single cylinder b. Multi-cylinder
7. According to speed of engine
a. Low speed b. Medium speed c. High speed
8. According to cooling of engine
a. Air cooled b. Water cooled
9. According to lubrication of engine
a. Splash lubrication b. Pressurised lubrication
10. According to application
a. Mobile engine b. Stationary engine
Construction of four stroke engine:
The 4 stroke engine consists of stationary as well as moving components. The
stationary components of the petrol engine are the cylinder, cylinder head, crankcase,
intake and exhaust manifold, spark plug or diesel injector. The moving components of
the engine are piston, connecting rod, crank and crankshaft, intake and exhaust valves.
The cylinder head is mounted over the cylinder block and the piston is placed inside
the cylinder to form a cylinder cavity or combustion chamber. The piston easily
reciprocates inside a cylinder and it is connected to the crankshaft with the help of a
connecting rod. This helps to convert reciprocating motion of piston into rotary
motion of the crankshaft. The inlet and exhaust ports are mounted into the cylinder
head. The inlet valve actuates to control from the intake manifold into the engine
cylinder and the exhaust valve actuates to control the removal of exhaust gases from
cylinder to the exhaust manifold.
Four stroke engine
, Working of four stroke Petrol Engine:
The working of the four stroke petrol engine is done by four strokes of piston:-
1) Inlet Stroke:- While inlet stroke, the piston moves from TDC to BDC with the
inlet valve in open condition and the exhaust valve is in closed condition. During this
stroke, as the piston moves from TDC to BDC, a partial vacuum is created inside the
cylinder to bring the air-petrol mixture from intake manifold into the cylinder. At the
end of the Inlet stroke when the piston reaches the BDC, the inlet valve is closed.
2) Compression Stroke:– During the compression stroke, the piston compresses the
air-petrol mixture to high pressure, by moving from the BDC toward TDC. During
this stroke, both valves (Inlet and Exhaust) remain closed. At the end of the
compression stroke, the spark plug produces the spark to ignite the air-petrol mixture.
3) Power Stroke:- In this stroke, the high-pressure combustion products push the
piston downward (toward BDC) to expand. Hence, the piston gets power due to the
expansion of combustion products. During the power, stroke piston moves from the
TDC toward BDC. At the end of the power stroke, the exhaust valve begins to open.
4) Exhaust Stroke:- In exhaust stroke, the piston moves from BDC to TDC. During
this stroke, burnt gases are released to exhaust pipe through an open exhaust valve.
The exhaust valve closes when the exhaust stroke is completed. After exhaust valve
closes, the intake valve again opens for air-petrol mixture to enter the cylinder.
Working of four stroke Diesel Engine:
The working of the 4-stroke diesel engine is done by four strokes:-
1) Inlet Stroke:- While inlet stroke, the piston moves from TDC to BDC with the
inlet valve in open condition and the exhaust valve is in closed condition. During this
stroke, as the piston moves from TDC to BDC, a partial vacuum is created inside the
cylinder that helps to bring the air from the intake manifold into the cylinder. At the
end of the suction stroke when the piston reaches the BDC, the inlet valve is closed.
MECHANICAL AND CIVIL ENGINEERING
UNIT – I
THERMAL ENGINEERING
Classification of internal combustion engine
Working of two stroke petrol engine
Working of two stroke diesel engine
Working of four stroke petrol engine
Working of four stroke diesel engine
Classification of Boilers
Cochran boiler
Locomotive boiler
Classification of Power plants
Working of Thermal power plant
Working of Nuclear power plant
Working of Solar power plant
Working of Wind power plant
Working of Tidal power plant
Working of Geothermal power plant
,Internal Combustion engine – I C engine:
The internal combustion (IC) engine is a heat engine converts chemical energy of fuel
into shaft work. The combustion occurs inside a cylinder and the piston is pushed
down by combustion gas to revolve the crankshaft to perform work.
Classification of internal combustion engine:
I.C. engines can be classified as follows:
1. According to type of ignition of fuel
a. Spark Ignition b. Compression Ignition engine
2. According to type of fuel used
a. Petrol engine b. Diesel engine
3. According to number of strokes required for power
a. Two strokes b. Four strokes
4. According to Thermodynamic cycle
a. Otto cycle b. Diesel cycle
5. According to cylinder arrangement
a. Vertical b. Horizontal
6. According to number of cylinders
a. Single cylinder b. Multi-cylinder
7. According to speed of engine
a. Low speed b. Medium speed c. High speed
8. According to cooling of engine
a. Air cooled b. Water cooled
9. According to lubrication of engine
a. Splash lubrication b. Pressurised lubrication
10. According to application
a. Mobile engine b. Stationary engine
Construction of four stroke engine:
The 4 stroke engine consists of stationary as well as moving components. The
stationary components of the petrol engine are the cylinder, cylinder head, crankcase,
intake and exhaust manifold, spark plug or diesel injector. The moving components of
the engine are piston, connecting rod, crank and crankshaft, intake and exhaust valves.
The cylinder head is mounted over the cylinder block and the piston is placed inside
the cylinder to form a cylinder cavity or combustion chamber. The piston easily
reciprocates inside a cylinder and it is connected to the crankshaft with the help of a
connecting rod. This helps to convert reciprocating motion of piston into rotary
motion of the crankshaft. The inlet and exhaust ports are mounted into the cylinder
head. The inlet valve actuates to control from the intake manifold into the engine
cylinder and the exhaust valve actuates to control the removal of exhaust gases from
cylinder to the exhaust manifold.
Four stroke engine
, Working of four stroke Petrol Engine:
The working of the four stroke petrol engine is done by four strokes of piston:-
1) Inlet Stroke:- While inlet stroke, the piston moves from TDC to BDC with the
inlet valve in open condition and the exhaust valve is in closed condition. During this
stroke, as the piston moves from TDC to BDC, a partial vacuum is created inside the
cylinder to bring the air-petrol mixture from intake manifold into the cylinder. At the
end of the Inlet stroke when the piston reaches the BDC, the inlet valve is closed.
2) Compression Stroke:– During the compression stroke, the piston compresses the
air-petrol mixture to high pressure, by moving from the BDC toward TDC. During
this stroke, both valves (Inlet and Exhaust) remain closed. At the end of the
compression stroke, the spark plug produces the spark to ignite the air-petrol mixture.
3) Power Stroke:- In this stroke, the high-pressure combustion products push the
piston downward (toward BDC) to expand. Hence, the piston gets power due to the
expansion of combustion products. During the power, stroke piston moves from the
TDC toward BDC. At the end of the power stroke, the exhaust valve begins to open.
4) Exhaust Stroke:- In exhaust stroke, the piston moves from BDC to TDC. During
this stroke, burnt gases are released to exhaust pipe through an open exhaust valve.
The exhaust valve closes when the exhaust stroke is completed. After exhaust valve
closes, the intake valve again opens for air-petrol mixture to enter the cylinder.
Working of four stroke Diesel Engine:
The working of the 4-stroke diesel engine is done by four strokes:-
1) Inlet Stroke:- While inlet stroke, the piston moves from TDC to BDC with the
inlet valve in open condition and the exhaust valve is in closed condition. During this
stroke, as the piston moves from TDC to BDC, a partial vacuum is created inside the
cylinder that helps to bring the air from the intake manifold into the cylinder. At the
end of the suction stroke when the piston reaches the BDC, the inlet valve is closed.
