summer training report

A

SUMMER TRAINING REPORT

Submitted By: Asha Kumari

Submitted to:

Mr. Laxman Kumar Pandey

Department of

Mechanical & Automation Engineering

Amity School of Engineering & Technology

Amity University Rajasthan

1

2014

ACKNOWLEGMENT

It has come out to be a great pleasure and experience for me to be a summer trainee

at Vipul Motors (MSIL).I wish to express my indebtedness to those who guided and

helped me, Mr. Laxman Kumar Pandey, Mr. Amit Sharma, Naresh Dutta (General

Manager, Vipul Motors) & Mr.ChandraShekhar. This would not have been

successful without their help and precious suggestions. Finally I want to thank all my

colleagues who made the experience good at the training.

Asha Kumari

TABLE OF CONTENTS

1. Introduction……………………………………………….

…………….............5

2. Transmission

Systems.........................................................................................7

3. Manual Transmission

System.............................................................................9

3.1

Advantage.....................................................................................................10

3.2

Clutch............................................................................................................10

3.3 Gear Box in Front Wheel Drive or

Transaxle...............................................12

3.4Gear Box in Rear Wheel

Drive.......................................................................13

3.5 Gear Shift

Lever.............................................................................................14

3.6 Shift

Fork........................................................................................................15

3.7 Gear Shift Control Lever and Cable

Components..........................................16

3.8 Gear Shift and Select Shaft Assembly

components........................................17

3.9 Gear Shift

mechanism.....................................................................................17

3.10. Input Shaft And Counter Shaft Assembly

components................................20

3.11. Gear

Box.......................................................................................................20

3.12 The Drive

Shaft..............................................................................................30

3.13 Differential Gear

Box.....................................................................................31

3.14 Transfer Gear

Box..........................................................................................34

3.15 Defects in Gear

Box.......................................................................................34

3.16 Manual Transmission Symptom

Diagnosis....................................................35

4. Automatic

Transmission..........................................................................................36

4.1

Description.......................................................................................................3

7

4.2 Functions of Components..........................................................................38

4.3 Automatic Transmission Modes.................................................................39

4.4 Electronic Control....................................................................................39

5. Automatic Manual Transmission………………………………………………..

…48

5.1 Direct Shift Transmission…………………………………………………...

…48

5.2 Electro Hydraulic Manual

Transmission………………………………………49

5.3

Advantages…………………………………………………………………….50

5.4

Disadvantages………………………………………………………………….50

6. Continuously Variable

Transmission………………………………………………51

6.1 Advantage of the

CVT…………………………………………………………52

6.2 Disadvantage of the

CVT……………………………………………………...52

7. Advance

Features…………………………………………………………………..53

7.1 Detent Pin

Technology………………………………………………………...53

7.2 Diagonal Shift

Assistance……………………………………………………...54

7.3 Reverse Shift

Prevention……………………………………………………….54

7.4 Reverse Gear

Actuation………………………………………………………..55

8. Case

Study……………………………………………………………………........56

9.

Conclusion………………………………………………………………………….

58

10.

Reference………………………………………………………………………….5

9

1. INTRODUCTION

Before the steam engine was invented, all of the physically demanding jobs like

construction, agriculture, shipping, and even traveling, were done by strong animals

or human beings themselves. The invention of the steam engine prompted the

Industrial Revolution, at which time human beings started using automated machines

to reduce human work load and increase job efficiency.

Even though it solves the dimension and slow start issues of the steam engine, the

internal combustion engine generates another serious problem. When the piston is

running at high speed, the pressure needed is also high, which violates the physics

rule of motion. Running an engine at high speed with high pressure is not efficient,

and also decreases the engine life. To solve this problem, the transmission system

was invented.

To transfer engine power efficiently, the gear ratio between the engine and wheels

plays a very important role. When we use a screwdriver, the portion we hold has a

larger diameter, while the portion contacting with the screw has smaller diameter.

This design makes users use less force to unscrew a screw while applying force on a

larger diameter portion of the screw driver. Therefore, attaching a smaller gear to the

engine side and connecting it to a larger gear to deliver power to wheels helps

overcome friction when moving a static vehicle.

The figure 2 shows that the large gear of the wheels needs less force to drive it.

However, it also shows that when the engine gear turns one circle, the wheel gear

only turns about one half. The car won’t run as fast as possible.

Consider the following situation from Figure 3: the wheel gear has a smaller size,

which needs more force to move it while the car is static.

It won’t even be possible to move the car if the engine power is not large enough.

However, when the engine gear turns 1 cycle, the wheel gear may turn 2, which

makes the car run faster.

Based on the physics rule of motion, after the object starts moving, the driving force

needed becomes smaller. Therefore, if the car can run on the large gear condition

(Figure 2) when starting, but change to a small gear (Figure 3) when moving, that is,

applying a large force when starting, but a small force when moving, this will makes

the power transmission much more efficient.

2. TRANSMISSION SYSTEMS

The most common transmission systems used in Maruti cars the automotive industry

are:

• Manual transmission,

• Automatic transmission,

• Semi-automatic transmission,

• Continuously-variable transmission (C.V.T.).

Manual Transmission

The first transmission invented was the manual transmission system. The driver

needs to disengage the clutch to disconnect the power from the engine first, select the

target gear, and engage the clutch again to perform the gear change. This will

challenge a new driver. It always takes time for a new driver to get used to this skill.

Automatic Transmission

An automatic transmission uses a fluid-coupling torque converter to replace the

clutch to avoid engaging/disengaging clutch during gear change. A completed gear

set, called planetary gears, is used to perform gear ratio change instead of selecting

gear manually. A driver no longer needs to worry about gear selection during driving.

It makes driving a car much easier, especially for a disabled or new driver. However,

the indirect gear contact of the torque converter causes power loss during power

transmission, and the complicated planetary gear structure makes the transmission

heavy and easily broken.

Semi-Automatic Transmission

A semi-automatic transmission tries to combine the advantages of the manual and

automatic transmission systems, but avoid their disadvantages. However, the

complicated design of the semi-automatic transmission is still under development,

and the price is not cheap. It is only used for some luxury or sports cars currently.

Continuously Variable Transmission (C.V.T.)

The Continuously Variable Transmission (C.V.T.) is a transmission in which the

ratio of the rotational speeds of two shafts, as the input shaft and output shaft of a

vehicle or other machine, can be varied continuously within a given range, providing

an infinite number of possible ratios. The other mechanical transmissions described

above only allow a few different gear ratios to be selected, but this type of

transmission essentially has an infinite number of ratios available within a finite

range. It provides even better fuel economy if the engine is constantly made run at a

single speed. This transmission is capable of a better user experience, without the rise

and fall in speed of an engine, and the jerk felt when changing gears. Maruti offers

C.V.T. transmission in” KIZASHI”

3. MANUAL TRANSMISSION SYSTEM

Manual transmissions also referred as stick shift transmission or just ‘stick', 'straight

drive', or standard transmission because you need to use the transmission stick every

time you change the gears. To perform the gear shift, the transmission system must

first be disengaged from the engine. After the target gear is selected, the transmission

and engine are engaged with each other again to perform the power transmission.

Manual transmissions are characterized by gear ratios that are selectable by locking

selected gear pairs to the output shaft inside the transmission. The transmission

provides five forward speeds and one reverse speed by means of three synchromesh

devices and three shafts-input shaft, countershaft and reverse gear shaft. All forward

gears are in constant mesh, and reverse uses a sliding idler gear arrangement. The

low speed synchronizer sleeve & hub is mounted on countershaft and engaged with

countershaft 1st gear or 2nd gear, while the high speed synchronizer sleeve & hub is

done on input shaft and engaged with input shaft 3rd gear or 4th gear. The 5th speed

synchronizer sleeve & hub on input shaft is engaged with input shaft fifth gear

mounted on the input shaft. The double cone synchronizing mechanism is provided

to 2nd gear synchromesh device for high performance of shifting to 2nd gear. The

countershaft turns the final gear and differential assembly, thereby turning the front

drive shafts which are attached to the front wheels.

The Components of a Transmission System are

• Clutch

• Gear Box/Transaxle

• Differential

• Drive Shaft/Axle

• Propeller Shaft

• Transfer Gear Box

3.1 ADVANTAGES

• Cars with M/T are cheaper to buy• Gives higher fuel efficiency• Has lower maintenance cost• Gives complete control to driver

3.2 CLUTCH

3.2.1. Construction

The clutch is a diaphragm spring clutch of a dry single disc type. The diaphragm

spring is of a tapering-finger type, which is a solid ring in the outer diameter part,

with a series of tapered fingers pointing inward. The disc, carrying four torsional coil

springs, is positioned on the transaxle input shaft with an involute spline fit. The

clutch cover is secured to the flywheel, and carries diaphragm spring in such a way

that the peripheral edge part of the spring pushes on the pressure plate against

flywheel (with the disc in between), when the clutch release bearing is held back.

This is the engaged condition of the clutch. Depressing the clutch pedal causes the

release bearing to advance and pushes on the tips of the tapered fingers of the

diaphragm spring. When this happens, diaphragm spring pulls the pressure plate

away from flywheel, thereby interrupting the flow of drive from flywheel through

clutch disc to transaxle input shaft.

The three main parts of clutch are:

1. Driving member: consists of a flywheel mounted on the engine crank shaft.

The flywheel is bolted to cover which carries a pressure plate or driving disc,

pressure springs and releasing levers.

2. Driven member: consists of a disc or plate called clutch plate. It is free to

slide length wise on the splines of the clutch shaft.

3. Operating member: consists of a foot pedal, linkage, release or throw-out

bearing, release levers and springs necessary to ensure the proper operation of

the clutch.

3.2.2. Clutch System Symptoms Diagnosis

3.3. Gear Box in Front Wheel Drive or Transaxle

A separate clutch shaft drives the input shaft via a splined coupling. The gears on the

countershaft are meshed with the gears on the input/main shaft. In a transaxle the

drive is directly transmitted to the differential.

• Reverse gear shaft is generally located in the gear box above the input shaft.

• The reverse idler gear is located on this shaft.

• The idler gear is meshed with the reverse gear to reverse the motion of the

vehicle.

3.4. Gear Box in Rear Wheel Drive

A separate clutch shaft drives the input shaft via a splined coupling. The gears on the

countershaft are meshed with the gears on the main shaft. In this reverse shaft is

below countershaft.

3.5. Gear Shift Lever

• The gear shift lever is present inside the drive compartment of the vehicle.

• The purpose of a gear shift lever is enable the driver to select different

gears during the drive.

• The car may have 4 or 5 forward gears and a reverse gear which can be

selected as per the driving needs.

• Gear shift lever mechanism is of 2 types:

1. Direct shift type

2. Indirect shift type

3.5.1. Indirect Shift Type

• In this type of shifting mechanism a cable or a rod connects the lever to

the transmission.

• This type of shifting mechanism is generally used in front wheel drive

vehicles.

3.5.2. Direct Shift Type

.

• In this type, the shift lever is connected directly to the transmission.

• This type of shift lever mechanism is used in rear wheel drive vehicles.

3.6. Shift Fork

• The shift fork is connected to the gear shift shaft, it is used to engage the hub

assembly with the selected gear.

• The shift fork is connected to the gear shift lever by the shift shaft.

• When the gear is selected the corresponding shift forks which are connected

to the shift shaft also move.

• During a gear change one shift fork moves one hub assembly away from the

gear and another shift fork moves the hub assembly for the newly selected

gear.

3.7. Gear Shift Control Lever and Cable Components

3.8. Gear Shift and Select Shaft Assembly components

3.9. Gear Shift Mechanism

The gear shifting control system consists of the following main parts. Movement of

gear shift control lever assembly (16) is transmitted to gear shift & select shaft

assembly (10) through gear shift control cable (1) and gear select control cable (2).

3.9.1. 5th & Reverse Gear Shift Cam

5th & reverse gear shift cam, cam guide return spring and 5th to reverse interlock

guide bolt are provided to prevent the gear from being directly shifted from 5th to

reverse.

• When shift lever is at neutral position between 3rd and 4th gear, 5th & reverse

gear shift cam (2) is under 5th to reverse interlock guide bolt (5) and can turn

freely clockwise (to 3rd gear) and counterclockwise (to 4th gear).

• When shift lever is shifted toward right from neutral position, shift & select

shaft (1) moves up but 5th & reverse gear shift cam (2) is restricted by 5th to

reverse interlock guide bolt (5) and return spring (3) is contracted.

• When shift lever is shifted to 5th gear, shift & select shaft (1) turns clockwise

letting 5th & reverse gear shift cam (2) off from guide bolt and pushed up by

return spring (3). In this state, movement of shift cam is restricted by 5 th to

reverse interlock guide bolt (5) and therefore, gearshift to reverse is not

attainable.

• When shift lever is shifted from neutral position between 5th gear and reverse

gear to reverse gear, 5th & reverse gear shift cam (2) turns counterclockwise

to attain reverse gear.

3.10. Input Shaft And Counter Shaft Assembly components

3.10.1. Input shaft

• Input shaft is a cylindrical shaped body which is used to transmit the power

from the clutch to the gear box.

• The drive received from the clutch is transmitted through a system of gears to

the countershaft.

3.10.2. Countershaft/Lay shaft

• Counter shaft or lay shaft is a cylindrical metal body which runs parallel to

the main shaft.

• Countershaft has a set of gears splined onto its surface.

• The gears on the countershaft are meshed with the gears on the input/main

shaft.

• In a transaxle the drive is directly transmitted to the differential.

3.10.3. Main Shaft/Output Shaft

• Main shaft is cylindrical shaped metal body which transmits the drive from

the gear box to the differential.

• Gears are splined on its surface and are connected to the countershaft.

• The rotation of the main shaft with respect to the input shaft is controlled by

the gear ratio.

• The above type of arrangement is generally found in rear wheel drive

vehicles.

3.11. Gear Box

The following types of gear box are used in automobiles:

1. Sliding Mesh

2. Constant Mesh

3. Synchromesh

3.11.1. SLIDING MESH GEAR BOX

It is the simplest gear box. The following figure shows 4-speed gear box in neutral

position. 4 gears are connected to the lay shaft/counter shaft. A reverse idler gear is

mounted on another shaft and always remains connected to the reverse gear of

countershaft. This “H” shift pattern enables the driver to select four different gear

ratios and a reverse gear.

Gears in Neutral:

When the engine is running and clutch is engaged the clutch shaft gear drives the

countershaft gear. The countershaft rotates opposite in direction of the clutch shaft. In

neutral position only the clutch shaft gear is connected to the countershaft gear. Other

gears are free and hence the transmission main shaft is not turning. The vehicle is

stationary.

First or low shaft gear:

By operating the gear shift lever the larger gear on the main shaft is moved along the

shaft to mesh with the first gear of the counter shaft. The main shaft turns in the same

direction as that of the clutch shaft. Since the smaller countershaft is engaged with

larger shaft gear a gear reduction of approximately 4:1 is obtained i.e. the clutch shaft

turns 4 times for each revolution of main shaft.

Second speed gear

By operating the gear shift lever the third gear on the main shaft is moved along the

shaft to mesh with the third gear of the counter shaft. The main shaft turns in same

direction as clutch shaft. A gear reduction of approximately 3:1 is obtained.

Third speed gear

By operating the gear shift lever, the second gear of the main shaft and countershaft

are demeshed and then the third gear of the main shaft are forced axially against the

clutch shaft gear. External Teeth on the clutch shaft gear mesh with the internal teeth

in the third and top gear. The main shaft turns in same direction as clutch shaft. A

gear reduction of approximately 2:1is obtained i.e. the clutch shaft turns 2 times for

each revolution of main shaft.

.

Fourth speed gear/ Top or High-Speed Gear

By operating the gear shaft lever the third gears of the main and countershaft is

demeshed and the gears present on the main shaft along with the shaft is forced

axially against the clutch shaft gear. External teeth present on the main shaft engage

with the internal teeth present on the main shaft. The main shaft turns along with the

clutch shaft and a gear ratio of approximately 1:1 is obtained.

Reverse gear

By operating the gear shift lever, the last gear present on the main shaft is engaged

with the reverse idler gear. The reverse idler gear is always in mesh with the counters

haft gear. Interposing the idler gear between the counter-shaft reverse gear and main

shaft gear, the main shaft turns in the direction opposite to the clutch shaft. This

reverses the rotation of the wheels so that the wheel backs.

3.11.2. CONSTANT MESH GEARBOX

In this type of gear box, all gears of the main shaft are in constant mesh with the

corresponding gears of the countershaft (Lay shaft). Two dog clutches are provided

on the main shaft- one between the clutch gear and the second gear, and the other

between the first gear and reverse gear. The main shaft is splined and all the gears are

free on it. Dog clutch can slide on the shaft and rotates with it. All the gears on the

countershaft are rigidly fixed with it.

When the left hand dog clutch is made to slide to the left by means of the gear shift

lever, it meshes with the clutch gear and the top speed gear is obtained. When the left

hand dog clutch meshes with the second gear, the second speed gear is obtained.

Similarly by sliding the right hand dog clutch to the left and right, the first speed gear

and reverse gear are obtained respectively. In this gear box because all the gears are

in constant mesh they are safe from being damaged and an unpleasant grinding sound

does not occur while engaging and disengaging them.

3.11.3. SYNCROMESH GEAR BOX

In sliding Mesh Gear box the two meshing gears need to be revolve at equal

peripheral speeds to achieve a jerk less engagement and it is true for constant mesh

gear box in which the peripheral speeds of sliding dog and the corresponding gear on

the output shaft must be equal. The peripheral speed is given by:

ν= лd1N1=лd2N2

Where d1 and N1 are pitch circle diameter and r.p.m. of gear and d2 and N2 diameter

and r.p.m. of attached dog respectively. Now N1 ≠ N2 since d1 ≠ d2. Thus there is a

difference in gear and dog which necessitates double declutching. The driver has to

disengage the clutch twice in quick succession therefore it is referred as double

declutching. There are two steps involved in this process:

1. The clutch is disengaged i.e. first declutching and the gear system is placed in

its neutral position. Now the clutch is reengaged and acceleration pedal is

pressed to adjust the engine speed according to driver’s judgment.

2. The clutch is disengaged(i.e. second declutching) again the appropriate gear is

engaged and then the clutch is re-engaged.

It is that gear box in which sliding synchronizing units are provided in place of

sliding dog clutches as in case of constant mesh gear box. With the help of

synchronizing unit, the speed of both the driving and driven shafts is synchronized

before they are clutched together through train of gears. The arrangement of power

flow for the various gears remains the same as in constant mesh gear box. The

synchronizer is made of frictional materials. When the collar tries to mesh with the

gear, the synchronizer will touch the gear first and use friction force to drive the gear

to spin at the same speed as the collar. This will ensure that the collar is meshed into

the gear very smoothly without grinding.

Synchromesh gear devices work on the principle that two gears to be engaged are

first bought into frictional contact which equalizes their speed after which they are

engaged readily and smoothly. The following types of devices are mostly used in

vehicles:

i. Pin Type

ii. Synchronizer ring type

A synchronizing system is used for smooth meshing. Synchromesh works like a

friction clutch. In the following figure two conical surfaces cone-1 is the part of the

collar and the cone-2 is the part of the gear wheel. Cone1, 2 are revolving at different

speeds. While cone-2 is revolving, cone-1 gradually slides into it. Friction slows or

speeds up the gear

wheel. Finally both the

cones revolve at same

speed.

In the following Fig. collar and gear wheel are separate and they are revolving at

different speeds. The internal cone comes in contact with the outer cone of the gear

wheel. Friction slows or speeds up the gear wheel.

And when the collar and gear wheel rotate at same speed the spring loaded outer ring

of the collar is pushed forward. The dog slides smoothly into mesh without clashing.

The collar and gear wheel lock and revolve at same speed. This is the principle of

synchromesh.

The advantage of this type of gear

transmission has an advantage of

allowing smooth and quick shifting

of gears without quick shifting gears

without danger of damaging of gears

and without necessity for double

clutching.

3.12. The Drive Shaft

The drive shaft, or propeller shaft, connects the transmission output shaft to the

differential pinion shaft. Since all roads are not perfectly smooth, and the

transmission is fixed, the drive shaft has to be flexible to absorb the shock of bumps

in the road. Universal, or "U-joints" allow the drive shaft to flex (and stop it from

breaking) when the drive angle changes.

Drive shafts are usually hollow in order to weigh less, but of a large diameter so that

they are strong. High quality steel, and sometimes aluminum are used in the

manufacture of the drive shaft. The shaft must be quite straight and balanced to avoid

vibrating. Since it usually turns at engine speeds, a lot of damage can be caused if the

shaft is unbalanced, or bent. Damage can also be caused if the U-joints are worn out.

There are two types of drive shafts, the Hotchkiss drive and the Torque Tube Drive.

The Hotchkiss drive is made up of a drive shaft connected to the transmission output

shaft and the differential pinion gear shaft. U-joints are used in the front and rear.

The Hotchkiss drive transfers the torque of the output shaft to the differential. No

wheel drive thrust is sent to the drive shaft. Sometimes this drive comes in two pieces

to reduce vibration and make it easier to install (in this case, three U-joints are

needed).The two-piece types need ball bearings in a dustproof housing as center

support for the shafts. Rubber is added into this arrangement for noise and vibration

reduction.

The torque tube drive shaft is used if the drive shaft has to carry the wheel drive

thrust. It is a hollow steel tube that extends from the transmission to the rear axle

housing. One end is fastened to the axle housing by bolts. The transmission end is

fastened with a torque ball. The drive shaft fits into the torque tube. A U-joint is

located in the torque ball, and the axle housing end is splined to the pinion gear shaft.

Drive thrust is sent through the torque tube to the torque ball, to transmission, to

engine and finally, to the frame through the engine mounts. That is, the car is pushed

forward by the torque tube pressing on the engine.

3.13. Differential Gear Box

Differentials are a variety of gearbox, almost always used in one of two ways. In one

of these, it receives one input and provides two outputs; this is found in every

automobile. In automobile and other wheeled vehicles, the differential allows each of

the driving wheels to rotate at different speeds, while supplying equal torque to each

of them. In the other, less commonly encountered, it combines two inputs to create an

output that is the sum (or difference) of the inputs. In automotive applications, the

differential and its housing are sometimes collectively called a "pumpkin" (because

the housing resembles a pumpkin).

3.13.1. Purpose

The differential gear box has following functions:

1. Avoid skidding of the rear wheels on a road turning.

2. Reduces the speed of inner wheels and increases the speed of outer wheels,

while drawing a curve.

3. Keeps equal speeds of all the wheels while moving on a straight road.

4.

Eliminates a single rigid rear axle, and provides a coupling between two rear

axles.

Power is supplied from the engine, via the transmission or gearbox, to a drive

shaft termed as propeller shaft, which runs to the differential. A spiral

bevel pinion gear at the end of the propeller shaft is encased within the differential

itself, and it meshes with the large spiral bevel ring gear termed as crown wheel. The

ring and pinion may mesh in hypoid orientation. The ring gear is attached to a carrier,

which holds what is sometimes called a spider, a cluster of four bevel gears in a

rectangle, so each bevel gear meshes with two neighbors and rotates counter to the

third that it faces and does not mesh with. Two of these spider gears are aligned on

the same axis as the ring gear and drive the half shafts connected to the

vehicle's driven wheels. These are called the side gears. The other two spider gears

are aligned on a perpendicular axis which changes orientation with the ring gear's

rotation. These two gears are just called pinion gears, not to be confused with the

main pinion gear. (Other spider designs employ different numbers of pinion gears

depending on durability requirements.) As the carrier rotates, the changing axis

orientation of the pinion gears imparts the motion of the ring gear to the motion of

the side gears by pushing on them rather than turning against them (that is, the same

teeth stay in contact), but because the spider gears are not restricted from turning

against each other, within that motion the side gears can counter-rotate relative to the

ring gear and to each other under the same force (in which case the same teeth do not

stay in contact).Thus, for example, if the car is making a turn to the right, the main

ring gear may make 10 full rotations. During that time, the left wheel will make more

rotations because it has further to travel, and the right wheel will make fewer

rotations as it has less distance to travel. The side gears will rotate in opposite

directions relative to the ring gear by, say, 2 full turns each (4 full turns relative to

each other), resulting in the left wheel making 12 rotations, and the right wheel

making 8 rotations. The rotation of the ring gear is always the average of the

rotations of the side gears. This is why if the wheels are lifted off the ground with the

engine off, and the drive shaft is held (preventing the ring gear from turning inside

the differential), manually rotating one wheel causes the other to rotate in the

opposite direction by the same amount. When the vehicle is traveling in a straight

line, there will be no differential movement of the planetary system of gears other

than the minute movements necessary to compensate for slight differences in wheel

diameter, undulations in the road (which make for a longer or shorter wheel path),

etc.

3.13.2. Loss of Traction:

One undesirable side effect of a differential is that it can reduce overall torque - the

rotational force which propels the vehicle. The amount of torque required to propel

the vehicle at any given moment depends on the load at that instant - how heavy the

vehicle is, how much drag and friction there is, the gradient of the road, the vehicle's

momentum and so on.

3.14. Transfer Gear Box

The function of the transfer gear box is to distribute the torque generated in

the engine to all four wheels of the vehicle.

The transfer gear box is controlled by the driver, the control is located in the

vehicle compartment it is either in the form of a transfer lever or a button.

The transfer gear box connects the drive from the engine to the second

propeller shaft which transmits power to the front wheels of the vehicle.

3.15. DEFECTS IN GEAR BOX

The defects encountered in a Manual Transmission System are

• Abnormal Noise

• Gear Engagement and Disengagement Problems

• Gear Jumping Out

• Oil Leakage

3.16. Manual Transmission Symptom Diagnosis

4. AUTOMATIC TRANSMISSION

Automatic transmission or A/T has no clutch. It changes gears automatically as

vehicle moves, thus freeing the driver from hassle of shifting gears. This automatic

transmission is electronic full automatic transaxle with forward 4-speed and reverse

1-speed .The torque convertor is a 3 element,1-step and 2 phase type and is equipped

with an automatically controlled lock up mechanism.

The gear change device consists of a ravigenau type planetary gear unit 3 multiple

disc type clutches,3 multiple disc type brakes and 2 one way clutches.

The hydraulic pressure control device consists of valve body assembly, pressure

solenoid valve (linear solenoid), 2 shift solenoid valves, TCC solenoid valves (TCC

pressure control solenoid valve) and a timing solenoid valve. Optimum line pressure

complying with engine torque is produced by the pressure control solenoid valve in

dependence upon control signal from transmission control module (TCM). This

makes it possible to control the line pressure with high accuracy in accordance with

engine power and running conditions to achieve smooth shifting characteristics and

high efficiency.

A clutch-to-clutch control system is provided for shifting between third and fourth

gear. This clutch-to-clutch control system is made to function optimally, so that

hydraulic pressure controls such as shown below are conducted.

When upshifting from 3rd to 4th gear, to adjust the drain hydraulic pressure at

releasing the forward clutch, a timing solenoid valve is used to switch a hydraulic

passage with an orifice to another during shifting.

When downshifting from 4th to 3rd gear to adjust the line pressure applied to forward

clutch at engaging the forward clutch, a timing solenoid valve is used to switch a

hydraulic passage with an orifice to another during shifting.

When upshifting from 3rd to 4th gear with engine throttle opened, to optimise the line

pressure applied to the forward clutch at releasing the forward clutch, the learning

control is processed to compensate the switching timing of the timing solenoid at

every shifting.

When downshifting from 4th to 3rd gear with engine throttle opened, to optimize the

line pressure applied to the forward clutch, the learning control is processed to

compensate the line pressure ate every shifting.

4.1. DESCRIPTION

1st 2.875 Front sun gear 242nd 1.568 Rear sun gear 303rd 1.000 Long pinion gear 204th 0.697 Short pinion gear 19Rev 2.300 Ring gear 69

PrimaryFinal

PRND32L

TypeCapacity

2 sets

Number of teeth

Wet type multi-plate clutchWet type multi-plate brake

Forward 4-speed, rev. 1-speed, Ravigneau planetary gear

81-40LS3-element, 1-step, 2-phase with lock-up mechanism

2.02400 +/- 150 rpm

SUZUKI ATF 3317 or MOBIL 3309

Forward 1st <--->2nd<--->3rd (<---4th) automatic shiftForward 1st <--->2nd(<---3rd) automatic shiftForward 1st (<---2nd<---3rd) fixedRadiator-assisted cooling (water cooling)

Neutral, output shaft fixed, engine startReverseNeutral, output shaft free, engine startForward 1st <--->2nd<--->3rd<--->4th automatic shift

TypeType

Stall torque ratioStall speed

Torque converter

Forced pumping type by oil pump

One way clutch1.0234.277Direct cable shifting

Transmission

Shift mechanism

5.8 litres

Type

Control components

Reduction ratio

3 sets3 sets

Internal involute gear (non-crescent)Engine-driving

Gear ratio

LubricantLubrication

Oil pump

Cooling typeTypeDriveType

Type

Position

4.2. FUNCTION OF COMPONENTS

1.Input shaft 2.Front sun gear 3.Rear sun gear 4.Planetary long pinion 5.Planetary short pinion 6.Planetary carrier 7.Ring gear 8.Counter drive gear 9.Counter driven gear 10.Differential drive pinion

Symbol Part name FunctionC1 Forward clutch Meshes intermediate shaft with front sun gearC2 Direct clutch Meshes input shaft with planetary carrierC3 Reverse clutch Meshes intermediate shaft with rear sun gearB1 O/D & 2nd brake Fixes rear sun gearB2 Second brake Fixes rear sun gearB3 1st & reverse brake Fixes planetary carrierF1 One-way clutch No.1 Prevents rear sun gear form turning counterclockwise when B2 is activeF2 One-way clutch No.2 Prevents planetary carrier from turning counterclockwise

4.3. AUTOMATIC TRANSMISSION MODES

In order to select the mode, the driver would have to move a gear shift lever located

on the steering column or on the floor next to him/her. In order to select gears/modes

the driver must push a button in (called the shift lock button) or pull the handle (only

on column mounted shifters) out. In some vehicles position selector buttons for each

mode on the cockpit instead, freeing up space on the central console. Some of the

common modes are:

S1 S2 ST C1 C2 C3 B1 B2 B3 F1 F2Shift

solenoid valve No.1

Shift solenoid

valve No.2

TCC solenoid

valve

Forward clutch

Direct clutch

Reverse clutch

O/D & 2nd

coast brake

2nd brake

1st & reverse brake

One-way clutch No.1

One-way clutch No.2

O O X X X X X X X X XO O X X X O X X O X XO O X X X X X X X X X

1st O O X O X X X X X X O2nd O X X O X X X O X O X3rd X X + O O X X O X X X4th X O + X O X O O X X X1st O O X O X X X X X X O2nd O X X O X X X O X O X3rd X X + O O X X O X X X1st O O O O X X X X X X O2nd O X X O X X O O X O X

L 1st O O O O X X X X O X O

2

PRN

D

3

Solenoid Brake / Clutch / OWCO ON EngagedX OFF Free+ ON only when TCC is operating

4.4. ELECTRONIC CONTROL

The electronic control system consists of:

• Valve Body Components

• Solenoid Operation

• Input / Output Table

• Control Details

4.4.1. Valve Body Components

• A/T range switchThere is no terminal for range “3”.This SW informs starter, reverse lamp and TCM of A/T range to provide the following functions:

• E/G starts in “P” and “N” range only.• Reverse lamp turns on in “R” range.• Range signal is used for gear shift control.

• Shift solenoid No.1, No.2 (S1,S2)TCM actuate these solenoids to perform gear shift control.

1. N” reference line2. Lock washer needle3. Sensor bolt4. Manual select lever

• Timing solenoid (ST)Timing solenoid switches timing valve to:

• apply hydraulic pressure to C1 clutch (C1:Forward clutch).• control hydraulic pressure at C1 clutch drain orifice.

• Output/input speed sensor

S1, S2: Normal open typeCurrent OFF: Valve openCurrent ON: Valve closed

ST : Normal close typeCurrent OFF : Valve closedCurrent ON : Valve open

• Output speed sensor : Differential gear speed• Input speed sensor : C2 drum speed

• ATF temperature sensorAutomatic Transmission Fluid temperature signal is sent to TCM for gear shift control and hydraulic pressure control.

• Pressure control solenoid (SLT)Pressure control solenoid regulates the line pressure linearly according to the signal from TCM. .

• Lock up solenoid (SL)

.

4.4.2. Solenoid Operation

4.4.3. Input / Output Table

1. Pressure control solenoid valve (SLT)2. Shift solenoid valve "A" (S1)3. Shift solenoid valve "B" (S2)4. TCC pressure control solenoid valve (SL)5. Timing solenoid valve (ST)6. Temperature sensor clamp7. Valve body assembly8. Manual valve9. Solenoid lock plate10. O-ringFLD : Apply ATFX : Do not reuse(a) : 11Nm

Gea

r sh

ift c

ontr

ol

Shi

ft t

imin

g co

ntro

l

Tor

que

cont

rol

Slo

pe s

hift

con

trol

Lock

up

cont

rol

Slip

con

trol

Ove

rdriv

e in

hibi

t co

ntro

l

Line

pre

ssur

e co

ntro

l

Ove

rrun

con

trol

Rev

erse

con

trol

Squ

at c

ontr

ol

Throttle position o o o o o o oCoolant temperature o o o oEngine torque o o o oEngine speed o o o oA/C ON/OFF oStop lamp switch o o oRange "3" signal o o o oI/O shaft speed o o o o oVehicle speed o o o o o o o o oATF temperature o o o o o o oShift switch o o o o o o o o o o oTorque reduction request oSlip control signal oShift solenoid No.1 o o o o oShift solenoid No.2 o o o o oTiming solenoid o o oPressure control solenoid o oLock up solenoid o o

Input

Output

Control

Input/Output

4.4.4. Control Details

o Gear Shift Control

Gear shift control is performed according to the gear shift schedule shown in the

Service Manual

o Shift Timing Control

• [Input]

o Engine speed signal

o Input shaft speed signal

o Output shaft speed signal

• [Output]

TCM performs the following controls:

o Timing solenoid ON/OFF control

o Line pressure control solenoid duty control

o Learning Control

TCM learns the followings:

o Engage pressure applied to clutches and brakes

o Relief pressure at clutches and brakes

o Timing of application and relief of pressure

• [Purpose]

Shift shock reduction

a) Gear shifting without one-way clutch: between 3rd and 4th speeds

b) Gear shifting with one-way clutch between 1st and 2nd, 2nd and 3rd

speeds

- Double engagement is avoided by one-way clutch

o Overdrive Inhibit Control

1. At Low temperature

In: Input shaftOut: Output shaftC: ClutchB: Brake[A]Planetary gear free (engine speed rises unnecessarily)[B]Planetary gear locked

In: Input shaft Out: Output shaft C: Clutch B: BrakeF: One-way clutch

Overdrive is inhibited at low temperature.

:ECT < 50oC

:20oC<ATF<130oC

For a faster warming up

2. At “L”, “2” or “3” range

Overdrive is inhibited at “L”, “2” or “3” range

o Slip Control

• Slip: Partial engagement of torque converter clutch (lock up clutch) although

TP-VSS state is out of “lock-up zone”.

• During Acceleration

- Gear position is at 3rd or 4th.

- Throttle position and vehicle speed are in slip control zone

- Throttle position and vehicle speed are out of lock up zone

- 40oC<ATF temperature<110oC

- Not driving on an up slope

• During deceleration


- Throttle position is “idle”

- Engine speed > 1200 rpm

- Vehicle speed > 28km/h (at 3rd gear) or 41km/h (at 4th gear)

- 20oC<ATF temperature<110oC

- Not applying hard braking

o Squat Control

Gear is shifting to 2nd until the turbine torque is synchronized and then to 1st

when shifting from N to D to reduce a shock.

o Reverse Control

Gear Neutral1st 1st

2nd

N-D shift

When shifting the A/T select lever from “D”,”3”,”2”,”L” to “R” at 11km/h or

faster, reverse gear is not engaged to protect the automatic transmission.

o Overrun Control

When shifting the A/T select lever from D to 3, 2 or L during high speed

driving, TCM inhibits down-shifting until the vehicle speed goes down to the

specified level in order to prevent engine overrun and to protect automatic

transmission.

o Torque Control

• During shifting, engine torque will fluctuate and this will cause a shock.

• TCM sends torque reduction request signal to ECM when shifting starts.

• ECM retards the ignition timing to reduce the engine torque.

o Lock Up Control

Lock-Up OK condition

The following conditions are all met.


- Throttle position and vehicle speed in a lock-up range at “D” or “3” range.

- ATF temperatures are above 60oC.

- Stop lamp switch is OFF

Lock-Up NG condition

One of the conditions above is not met.

Ignition timing

Retard

o Line Pressure Control

TCM controls pressure control solenoid with duty signal according to the

following signals:

-Engine speed signal (from ECM)

-Throttle position signal (from ECM)

-ATF temperature signal

-Input shaft speed signal

-Output shaft speed signal

Lock up clutch status Throttle position Vehicle speedOver 89% 103-108

50% 67-7010% 39-44

Over 94% 93-9850% 56-6110% 35-40

Over 89% 139-14450% 82-8710% 53-58

Over 94% 129-13450% 73-7810% 51-56

3rd gear lock up

4th gear lock up

ON

OFF

ON

OFF

5. AUTOMATIC MANUAL TRANSMISSION

A automatic-manual transmission (also known as clutch less manual transmission,

automated manual transmission) is a system which uses electronic sensors,

processors and actuators to do gear shifts on the command of the driver. This

removes the need for a clutch pedal which the driver otherwise needs to depress

before making a gear change, since the clutch itself is actuated by electronic

equipment which can synchronize the timing and torque required to make gear shifts

quick and smooth. a semi-automatic transmission can also be switched to manual

mode to perform gear shifting at the drivers wish. The two most common semi-

automatic transmissions are:

1. Direct shift transmission (or dual-clutch transmission).

2. Electro-hydraulic manual transmission (or sequential transmission).

5.1 Direct shift transmission

In direct shift transmission direct shift gear box is used. The Direct-Shift Gearbox or

D.S.G. is an electronically controlled, twin-shaft dual-clutch manual gearbox,

without a conventional clutch pedal, with full automatic or semi-manual control.

Unlike the conventional manual transmission system, there are two different

gear/collar sets, with each connected to two different input/output shafts. The outer

clutch pack drives gears 1, 3, 5 and reverse. It is just like two conventional manual

transmission gear boxes in one. The inner clutch pack drives gears 2, 4, and 6.

Instead of a standard large dry single-plate clutch, each clutch pack is a collection of

four small wet interleaved clutch plates.

Due to space constraints, the two clutch assemblies are concentric. To automatically

shift from 1st gear to 2nd gear, first the computer detects that the spinning speed of the

input shaft is too high, and engages the 2nd gear’s collar to the 2nd gear. The clutch

then disengages from 1st gear’s input shaft, and engages the 2nd gear’s input shaft.

Controlled by computer, the gear shift becomes extremely fast compared with a

conventional manual transmission. Using direct contact of the clutch instead of fluid

coupling also improves power transmission efficiency.

Another advanced technology used for direct shift trans-mission allows it to perform

“double clutching” by shifting the gear to neutral first, adjusting the spinning speed

of the input shaft, and then shifting to the next gear. This makes gear shifting very

smooth.

5.2 Electro Hydraulic Manual Transmission

In electro-hydraulic manual transmission (also known as sequential transmission) the

gear set is almost the same as the conventional transmission system, except that the

shifting of the se-lector is not an “H” pattern. Instead, all selector forks are connected

to a drum. The drum has several grooves, and each has a ball sliding in it. Each fork

hooks up to a ball and can be moved forward and backward when the drum is

turning. Based on the pattern of the grooves on the drum, by turning the drum, each

fork can move forward and backward in turn, which makes gear selection sequential.

Therefore, it is impossible for an electro-hydraulic manual transmission to perform a

gear shift from 1st to 3rd or 4th to 2nd. The shifting must be sequential, like 1st ▬► 2nd

▬► 3rd ▬►4th, or 4th▬►3rd▬►2nd▬►1st.

5.3 Advantages

• Freedom from operating the clutch lever.

• Very comfortable for stop and go traffic.

• Better mileage than automatic transmission.

• Lower cost than automatic transmission.

5.4 Disadvantages

• More expensive than manual transmission.

• Not widely available

6. CONTINUOUSLY VARIABLE TRANSMISSION

The continuously-variable transmission is also an automatic transmission system,

which changes the diameters of input shaft and output shaft directly, instead of going

through several gears to perform gear ratio change. This design can generate an

infinite number of possible gear ratios. Unlike the complicated planetary automatic

transmission system, a C.V.T. only has three major parts:

1. A drive pulley connected to the input shaft.

2. A driven pulley connected to the

output shaft.

3. A belt.

.

This transmission is only offered in Maruti’s Kizashi model .In CVT’s, cars use a

pair of variable-diameter pulleys, each shaped like a pair of opposing cones, with a

metal belt or chain running between them. One pulley is connected to the engine

(input shaft), the other to the drive wheels (output shaft). The central component is

known as the variator: a transmission element resembling a V-belt connects two

axially adjustable sets of pulley halves. As the belt is a highly stressed component it

must be very strong and grip very well. These flexible belts are composed of several

(typically nine or 12) thin bands of steel that hold together high-strength, bow-tie-

shaped pieces of metal. They are also quieter than rubber-belt-driven CVTs. The

halves of each pulley are moveable; as the pulley halves come closer together the belt

is forced to ride higher on the pulley, effectively making the pulley's diameter larger.

Changing the diameter of the pulleys varies the transmission's ratio (the number of

times the output shaft revolves for each revolution of the engine), in the same way

that a 10-speed bike routes the chain over larger or smaller gears to change the ratio.

Making the input pulley smaller and the output pulley larger gives a low ratio (a large

number of engine revolutions producing a small number of output revolutions) for

better low-speed acceleration. As the car accelerates, the pulleys vary their diameter

to lower the engine speed as car speed rises.

6.1 Advantages of the CVT

• Ease of city Driving.

• Fuel economy similar to MT.

• Flexibility:

- Driving flexibility with Automatic and Manual modes.

- Two pedal drive for comfortable ride in start stop city traffic.

- Kick down function for meeting sudden acceleration requirement.

• Hassle free maintenance.

6.2 Disadvantages of the CVT

• Many drivers to not like it because you do not feel the engine accelerating.

• Higher cost.

• Transmitting motion by friction causes greater wear.

• Require special oil and other materials.

7. ADVANCE FEATURES

7.1 Detent Pin Technology

For gear shifting mechanism “Detent Pin” technology is being used for

reduced friction, smoother gear shift & better gear shift feel.

7.1.1 Functions of Detent pin

• Location and positioning of the required gearshift position.

• Locking in place once the gearshift position has been located.

• Ensuring precise and secure gearshift by means of a defined gearshift

resistance.

• Communicating a positive gearshift feel to the driver and a clear

sensation that the gear has been engaged.

7.2 Diagonal Shift Assistance

Diagonal Shift Assist (DSA) adds to the comfort by assisting in

effortless shifting from 5th to 4th gear .

7.3 Reverse Shift Prevention

• The cubic projection on the gear shift and select lever is blocked by the

projection of reverse shift limit yoke when gear shift control lever is shifted

from 5th position to reverse position.

• As cubic projection of gear shift and select lever pushes the reverse shift limit

yoke, the yoke rotates and pushes the cubic projection of the lever toward the

neutral position.

• Gear is shifted into 4th position if gear shift and select lever is still pushed

toward reverse position. Reverse shift limit yoke returns to original position

by spring force.

7.4 Reverse Gear Actuation

1. Gear shift and select lever2. Reverse shift limit yoke[A] : 5th[B] : Reverse[C] : 4th

Weight for New reverse gear actuation mechanism has been reduced by

150gm making lightest in all MSIL models.

8. CASE STUDY

MODEL MILEAGE VEHICLE SYSTEM

SX4 VDI 3664 Kms Transmission

Problem

A repeat complaint was received from the customer for fifth gear slippage in SX4-D

vehicle.

Observation

Vehicle was brought to the workshop and the defect mentioned by the customer was

confirmed during the road test.

Action Taken

• The problem of 5th gear slippage reported by the customer was confirmed

during the road test.

• Vehicle history was checked and it was found that vehicle had reported for

similar complaint at a mileage of 2890 Kms.

• As per vehicle history only circlip was changed during previous visit.

• Gear box was opened and 5th gear assembly was checked.

• 5th gear snap ring was found damaged.

• It caused improper meshing between fifth gear and its counter gear, which

caused chipping off or deep scoring on the gears.

• All the affected parts (gear, countershaft 5th, gear, input shaft 5th, circlip hub

assy, 5th speed sync, bearing,5th gear needle , ring, synchronizer) were

replaced

• Proper road test was taken and performance of the vehicle was found

satisfactory.

Root cause

Gear slippage was due to breakage of the circlip which resulted in improper meshing

of gears and chipping of gear teeth.

Remark

Thus in order to rectify such defect in one visit casual part (circlip) as well as

affected part (fifth gear) should be replaced.

9. CONCLUSION

The 6 weeks Industrial Training at “Maruti Suzuki Training Centre “was indeed the

most learning experience”. It provided me an opportunity to learn practical

application of my technical knowledge. I learnt a lot about automobile in basic

training and worked on transmission in cars. I learnt about different types of

transmission which are used in Maruti cars and the problems concerned with the

latter. During the training, I learnt of their advantages and disadvantages and the

advance features that Maruti Suzuki is introducing for customer satisfaction. Maruti

stands for the customer satisfaction in the market. Maruti Suzuki’s Tagline” WAY

OF LIFE” symbolize the changes within Suzuki. In addition, I gained a good

experience in term of self confidence, real life working situation, interactions among

people in the same field and working with others with different professional

background. I had an interest in understanding basic engineering work and practicing

what has been learnt in the class. Also, the training was an opportunity for me to

increase my human relation both socially and professionally.

10. REFERENCES

[1] http://www.auto.howstuffworks.com

[2] http://www.google.com

[3] http://en.wikipedia.org

[4] http://www.answers.com/

[5] http://www.familycar.com

[6] www.edmunds.com

[7] www.scribd.com

[8] www.workshopsmanual.com

[9] www.motorera.com

http://www.motorera.com/

http://www.workshopsmanual.com/

http://www.scribd.com/

http://www.edmunds.com/

http://www.familycar.com/

http://www.answers.com/

http://en.wikipedia.org/

http://www.google.com/

http://www.auto.howstuffworks.com/

summer training report

Engineering

gear shift lever

differential gear box

transfer gear box

gear shift mechanism

gear shift control lever

drive shaft

gea box

shift fork