Working systems in an automobile
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Transcript of Working systems in an automobile
To run an automobile a number of machines and
mechanism are implemented.
Different Systems like ignition , transmission , cooling
,suspension, exhaust , braking, lubrication system are
used in an automobile.
These all systems working in a single unit make the
automobile to work with it’s efficiency.
The manual transmission system introduced by
Louis- Rene Panhard and Emile Levassor in 1894.
The design of these two Frenchmen is still used in
every transmission system.
For initial motion of the vehicle, a hefty torque is
required as initial load and friction is more.
When the speed reaches to a extent, torque requirement
decreases.
To facilitate this variation , Transmission system comes
in existence
Clutch is used to disengage or engage the gearbox
with the flywheel for shifting the gears.
After engagement power is transmitted to wheel
through gear box, universal joints, propeller shaft,
differential, rear axle.
It should engage the engine and transmission system
gradually to avoid the jerky operation.
It works on the principle of friction and has friction
surfaces on both side.
Several gear ratios are provided by gear box that
allows driver to drive the vehicle at different speeds.
A typical gearbox contains Dog clutch, main shaft,
lay shaft, Selector Mechanism.
The gears mounted on main shaft don’t transmit
power to output shaft.
The power transmission is done with the help of dog
clutches.
Torque and speed variation are obtained using
selector mechanism.
When the 1st gear is selected the dog clutch moves towards
left and engages with 1st gear and the power is transmitted.
When we shift 5th gear, dog clutch engages with the smallest gear
and top speed in achieved an as a result torque is reduced.
The automatic transmission is a device that allows the
changing of the gears automatically.
Mainly 3 Types of automatic transmission are used.
I. Epicyclic gear Box,
II. Torque Convertor,
III.Continuously variable Transmission(CVT).
Automatic transmission does not has clutch pedal.
It is a double planetary gear set.
It consist of 2 Sun gears, 1 ring gear and 3 planet
gears for each sun gear.
All planet gears have single planet carrier.
5 gear ratios can be achieved by connecting or
locking the components.
The torque converter is a device which multiplies the
engine torque and also serves as automatic clutch to
transfer the engine torque.
There are three basic parts of torque converter. They
are:-
1. Impeller,
2. Turbine runner,
3. Stator..
Phase 1
Stall
Impeller rotates,
Turbine does not rotate
Brakes are applied
Phase 2
Acceleration
High impeller speed
Torque Multiplication
Phase 3
Coupling
Turbine gets 90% speed of impeller
Lock up clutch locks the impeller
and turbine
CVT gives numerous numbers of gear ratios
(almost infinite) from its maximum value to minimum
value .
It contains two cone shaped pulleys which are placed
opposite faced and the belt connecting them.
CVT most fuel efficient and very smooth driving
technology of the vehicle.
In the starting condition, the belt is on the smallest part
of input pulley and at the largest part of the output
pulley.
This provides high torque in the initial condition.
At the max. speed, the one end of belt is on the
largest part of I/P pulley and at the same time the
other part is on smallest part of O/P pulley.
This provides maximum speed to the vehicle.
At the different part of the pulley, different gear
ratios are achieved.
Friction phenomenon and lubrication in car
Purpose of lubrication in Car
How Lubrication System Works
Types of Lubricants
All rotating and moving machine parts of an automotive
engine have relative motion as they rub against each other.
Lubrication is required to reduce this rubbing action and
increase the life of the engine.
Lubrication System is mainly employed for 2 reasons:-
1. To reduce the rubbing action between the parts.
2. To dissipate the heat by reducing friction.
A separate system known as lubrication system is
provided in automotives to provide sufficient lubrication
against the friction.
There are three types of lubrication system Pressure
Feed Lubrication system Splash type lubrication system
Charge Lubrication system.
Lubrication: Clearance between moving parts are filled
with oil.
2. Cushioning: Oil layers between the mating parts
provide a cushioning effect against the sudden forces .
3. Cooling: As the oil moves around the engine parts and
cools the parts by absorbing the heat from the surfaces.
4. Cleaning: The piston rings and bearing of gudgeon pin
are exposed to the burned gases and gets contaminated .
Oil helps to wash out these deposits and keep the internal
environment.
5. Sealing: The oil film between the piston and cylinder
forms a seal by filling minute leakage.
6. Noise Reduction : Reduction of friction between the
two surfaces due oil film also decreases the
Lubricant is defined as the substance that improves
the engine efficiency by reducing wear and friction
when it introduced in between two moving surface.
Lubricants are made from base oil (90%) and
additives (10 %).
Vegetable oil, mineral oil; synthetic oil castor oil,
palm oil, sunflower oil and seed oil are some of the
example of base oil .
SAE 10w-20 is the multi graded oil SAE number
recommended by the manufacturer.
SAE stands for Society of Automotive Engineers.
Solid Lubricants:- Teflon or PTFE (Poly tetra fluoro
ethylene), graphite, boron nitride and , cadmium, gold
metal alloys, various bronze alloys are the solid
lubricants.
Advantages:-1. Ability to work under high loads.
2.High thermal stability.
Disadvantages:-1. Higher coefficient of friction and wear
2.Low stability of the lubrication film.
Liquid Lubricants:-Vegetable oil, mineral oil, synthetic
oil, castor oil, sunflower oil and seed oil are the common
liquid lubricants .
Semi Solid Lubricants:-Grease or molybdenum particles
are used as semi solid lubricants.
1.It reduces friction between two moving parts.
2.It acts as a cooling medium by removing heat.
3.Reduce wear of moving parts.
4.Keep engine parts clean by removing dust from the
parts and prevents corrosion of metallic parts.
5. Prevent deposition of carbon particles.
6.It also absorbs shock between two moving parts.
7.Forms good seal between piston rings and cylinder.
Definition
Requirement
Application
Types:-
Rotational Motion sensor
Pressure sensor
Temperature sensor
Linear & Angle position sensor
Principle:-
It works on the thermistor principle.
Definition:-
Temperature sensor generates voltage
according to the temperature of part and sends it to the ECU.
Uses:-
It is used to measure engine temperature and air
intake temperature.
Definition:-Air fuel ratio sensor is used to measure the individual
proportion of air and fuel in the air-fuel mixture that is supplied to the
engine.
Requirement:-To increases the fuel economy and to reduce the harmful
exhaust gases in the exhaust it is necessary to supply the ideal or
Stoichiometric air fuel ratio to the engine.
Function
Definition:-
Air intake pressure sensor is used to measure the
pressure of intake air, atmospheric air and vapour presents in the intake
manifold.
Requirement
Function
Definition:-Rain sensor is used to sense the amount of water on
the windshield when raining.
Requirement:-
It uses an advanced algorithm to determine how
much water is on the windshield.
Function