AGRI Grovestudies
Section A
1 a. Stroke - It
is the linear distance traveled by the piston from Top dead centre (TDC) to
Bottom dead centre (BDC).
1 b. TDC is TOP DEAD CENTRE….A term used in Vertical INTERNAL COMBUSTION (IC)
engine. It is the topmost position of a piston upto which it can reach after the
compression stroke or exhaust stroke.
1 c. Swept
volume - It is the volume (A x L) displaced by one stroke of the piston where A
is the cross sectional area of piston and L is the length of stroke.
OR
Swept Volume is volume between top dead centre and bottom dead centre. As piston moves from
one dead centre to another it sweeps this volume, so it is called swept volume. It is also called displacement volume. Which is mentioned in unit cc (cubic centimeter). Swept Volume tells how much fuel and/or air is sucked in and swept out of the engine.
Section B
2 a. There
are different sources of farm power available in India which are classified as
(i)
Human power
(ii)
Animal power
(iii)
Mechanical power (Tractors + Power tillers + Oil
engines)
(iv)
Electrical
power
(v)
Renewable energy (Biogas + Solar energy + Wind
energy)
2 b. Based on
combustion of fuel:
(i)
External combustion engine
(ii)
Internal combustion engine.
External combustion engine Here, the
working medium, the steam, is generated in a boiler, located out side the
engine and allowed in to the cylinder to operate the piston to do mechanical
work.
Internal combustion engine In internal
combustion engine, the combustion of fuel takes place inside the engine
cylinder and heat is generated within the cylinder. This heat is added to the
air inside the cylinder and thus the pressure of the air is increased
tremendously. This high pressure air moves the piston which rotates the crank shaft
and thus mechanical work is done.
2c. Four
stroke cycle engine - When the cycle is completed in two revolutions of the
crankshaft, it is called four stroke cycle engine.
FOUR STROKE CYCLE ENGINE ( DIESEL/ PETROL ENGINE) In four
stroke cycle engines the four events namely suction, compression, power and
exhaust take place inside the engine cylinder. The four events are completed in
four strokes of the piston (two revolutions of the crank shaft). This engine
has got valves for controlling the inlet of charge and outlet of exhaust gases.
The opening and closing of the valve is controlled by cams, fitted on camshaft.
The camshaft is driven by crankshaft with the help of suitable gears or chains.
2d. An internal
combustion (IC) engine has several major components, including:
Cylinder: It is the cylindrical chamber in which the combustion of
fuel takes place.
Piston: It is a cylindrical component that moves up and down
inside the cylinder. It is connected to the crankshaft through a connecting
rod.
Crankshaft: It converts the reciprocating motion of the piston into
rotary motion, which is then transmitted to the wheels in the case of an
automobile.
Connecting rod: It connects the piston to the crankshaft, transmitting power
from the former to the latter.
Spark Plug: It creates a spark in the combustion chamber to ignite the
fuel-air mixture.
Camshaft: It operates the intake and exhaust valves, controlling the
flow of air and fuel into the engine, and the exhaust out of it.
Valve Train: It consists of the valves, rocker arms, push rods, and
lifters that control the flow of air and fuel into the engine and exhaust out
of it.
Fuel System: It consists of a fuel pump, fuel injectors, carburetor,
and other components that supply the engine with fuel.
Ignition System: It includes the spark plug, distributor, ignition coil, and
other components that generate the spark to ignite the fuel-air mixture.
Lubrication System: It consists of an oil pump, oil filter, and oil cooler
that keep the engine lubricated and cool.
I.C.
Engines by AGRI Grovestudies (agrigovestudie.blogspot.com)
Section C
3 a.
3 b. The engine in
your car works best at a high temperature. When the engine is cold, components
wear out easily, emits more pollutants, and the engine becomes less efficient.
Thus, another important task of the cooling system is to allow the engine to warm up as quickly as possible, and then to maintain a constant engine temperature. The
main function of a cooling system is to ensure that the engine runs at its
optimum operating temperature. If the cooling system or any part of it fails,
it will overheat the engine, which can lead to many serious issues.
Radiator
The
radiator acts as a heat exchanger for the engine. It is usually made of
aluminum and has many small diameter pipes with fins attached to them.
Furthermore, it exchanges the heat of the hot water coming from the engine with
the ambient air. It also has a drainage plug, an inlet port, a sealed cover,
and an outlet port.
Water pump
When
the coolant cools after being in the radiator, the water
pump sends the fluid back to the cylinder block, heater
core, and cylinder head. Eventually, the liquid enters the radiator again,
where it cools down again.
4a. The fuel supply
system generally consists of the following components:
Fuel Tank: The fuel tank is a container where the petrol is
stored until it is needed by the engine.
Fuel Pump: The fuel pump is responsible for pumping the
petrol from the fuel tank to the engine. There are two types of fuel pumps -
mechanical and electric. A mechanical pump is driven by the engine itself,
while an electric pump is powered by electricity.
Fuel Filter: The fuel filter is designed to remove any
impurities or contaminants from the petrol before it reaches the engine. This
is important to ensure that the engine is not damaged by particles in the fuel.
Fuel Injectors: The fuel injectors are responsible for
delivering the correct amount of fuel to each cylinder of the engine. The
injectors are controlled by the engine's electronic control unit (ECU), which
uses input from various sensors to determine the correct amount of fuel to
inject.
Carburetor (Optional): Some older petrol engines use a
carburetor instead of fuel injectors. The carburetor mixes the petrol with air
in the correct ratio before delivering it to the engine.
4b.
