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

Engine

Clutch plate

Fly wheel

Pressure plate

Gear box

Clutch Pedal

Differential

Selector Mechanism

Engine

Flywheel

Gearbox input

Shaft

Gearbox output shaft

Differential

Wheels

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.

Gears on main shaft are mounted on bearing

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

Cushioning

Cooling

Cleaning

Sealing

Noise Reduction

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

Definition

Requirement

Function

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

Requirement

Function

Definition

Requirement

Function

Definition

Requirement

Function

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

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Automobile Engineering by Kripal Singh.