Mechatronic system based manual transmission

1. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 6, Issue 1, January (2015), pp. 92- 97© IAEME
92
MECHATRONIC SYSTEM BASED MANUAL
TRANSMISSION
P. Sarath Babu
Asst. Professor, Dept of Mechanical Engineering,
Vel Tech Dr. RR & Dr. SR Technical University, Avadi, Chennai-600062.
ABSTRACT
People using old second hand cars in cities, particularly novice drivers engage irrelevant
gears; this in turn leads to fuel wastage and importing more petrol and diesel. One simple solution is
to educate and alert the drivers. In the current paper we explain how to design a low cost, add-on
type of s assembly unit which can be fitted on any existing vehicle. This assembly unit along with
the necessary signal conditioning circuit with implemented on a microcontroller. By listening to this
alarm, the drivers can engage proper gear to enhance the fuel efficiency. By linking the speed and
load information available with the engine management system, with the proposed system, one can
even educate and guide a driver to use correct gears.
Keywords: Transmission, Code warrior IDE, Microcontroller.
I. INTRODUCTION
In the current scenario, fuel efficiency is considered to be the most important factor while
buying a vehicle (car) by any end user. Designing any fuel saving unit is always considered to be a
challenging task for engineers. In fact, it is relatively easy to implement such a system in modern
vehicles thanks to plenty of electronics available in it. But it is always an uphill task in improving the
fuel efficiency of older (or used) vehicles. The proposed system tries to solve this problem at a low
cost.
One simple way to improve the fuel efficiency [1] in any vehicle is to engage appropriate
gears, particularly according to the speed. A professional, trained driver does this properly. But non-
professional, particularly novice, self driving operators do not use relevant gears. The worst scenario
happens, in city driving conditions. Particularly under severe traffic conditions, the drivers engage
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ISSN 0976 – 6340 (Print)
ISSN 0976 – 6359 (Online)
Volume 6, Issue 1, January (2015), pp. 92-97
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2. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 6, Issue 1, January (2015), pp. 92- 97© IAEME
93
wrong gears. We would like to design an add-on electronic control unit which will guide the driver
through relevant audio alarms. By linking with the speed of the vehicle, one can advice a driver to
engage the correct gear.
II. ISSUES WITH GEAR SHIFTING SYSTEM
The major task of improving fixed-ratio gear-boxes and its control systems is decreasing of
acceleration time and shortening of gear-shift [4] time. They make high demands of gear-boxes for
automobiles. If we look at the gear-shift process on the basis of stated parameters, then the general
gear-shift time includes the following components:
• Time of driver’s reaction.
• Time of clutch operation.
• Time of gearshift mechanism operation.
• Time based on gearbox design.
It is crucial to control various gear combinations (ratios) to multiply engine speed and torque
during the gear shifting process in any manual transmission [1]. If everything is mechanical, then
there can be component failures. In today’s scenario drivers change the gears using palming method.
Drivers are not aware that specific speed ratios are received by the gearbox or not. Once the driver
accelerates the vehicle either in the forward or reverse direction, he has to know which gear was
being engaged. The amount of time needed for changing gears smoothly is also very important. This
time will increase according to the total travel time of the vehicle. To overcome this, the control
system shall receive transmission gear position information pertaining to a specific speed ratio. Once
the driver knows which gear was received by the transmission, he can drive the vehicle with relevant
gear. This is possible if we design an automatic sensing unit using sensor assembly.
III. TRANSMISSION
The purpose of transmission system is to provide high torque at the time of starting, hill
climbing, accelerating and pulling a load. The vehicle will have to face the resistances like wind
resistance, gradient resistance and rolling resistance. The tractive effort is different at various speeds.
The variation of total resistance to the vehicle motion should be equal to the tractive effort of the
vehicle at any given speed.
In an automobile, there are three types of transmissions namely
1. Manual
2. Automatic
3. Continuously variable
III.1 MANUAL TRANSMISSION
A manual transmission system is fundamentally a more efficient system because there is a
complete mechanical linking of engine, gearing and wheels. The manual transmission is placed amid
the drive shaft and the clutch, and designed to provide the torque necessary for the movement of the
vehicle by transferring the power of the engine to the drive wheels. During the transmission of
power, gears on shafts are meshed with each other. The driver shifts [4] the gears, with the use of the
gear stick.

3. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 6, Issue 1, January (2015), pp. 92- 97© IAEME
94
III.2 AUTOMATIC TRANSMISSION
Automatics are less fuel-efficient by design - they don't maintain a continuous mechanical
link between engine and wheels since the system always includes a fluid filled torque converter. A
torque converter is a hydraulic fluid coupling between engines and gearing. Automatic transmission
[5] is less fuel efficient than manual transmission primarily due to pumping losses in the torque
converter and hydraulic actuators [6]. In addition, a hydraulic control system demands power from
the engine. In the case of automatic transmission there is a mechanism that changes the gear ratio
automatically. This means that the driver does not have to change the gear manually.
III.3 CONTINUOUSLY VARIABLE TRANSMISSION
CVT (continuously variable transmission) is not well understood but offers fuel efficiency
benefits over both manuals and automatics. This type of transmission is becoming more widespread
because of its advantages. Like a manual system it has a direct mechanical link between engine,
gearing and wheels. Unlike a manual system it requires no clutch, no gear changing but infinite
gearing ratios. At the heart of the design is a single cone shaped gear replacing the various different
cogs in a manual gearbox. If the vehicle is traveling slowly the wider end of the cone is used and at
high speeds the smaller end is used. In effect the cone offers us an unlimited number of gears.
The proposed solution is a modification of add-on solution to the manual transmission system. The
main objective of this work is to develop sensor based automatic sensing assembly unit which can be
fitted on an existing gearbox unit externally.
IV. SPECIFIC OBJECTIVES OF THIS STUDY ARE SUMMARIZED AS FOLLOWS
• To develop the necessary sensor assembly unit for detecting the position of the gear stick.
• To develop the required mechanical unit to house the sensor assembly.
• Display unit which shows which desired gear is engaged in the transmission system.
V. DESIGN OF SMART SYSTEM
The system design of the proposed ECU (Electronic Control Unit) comprises of designing the
following parts.
1. Assembly unit
2. Mechanical unit
3. Display unit
V.1 ASSEMBLY UNIT
The IR sensors are mounted in the sensor assembly. Assembly will sense the gear position of
the gear stick. Code Warrior is an IDE designed to support the software development for all
microcontroller products manufactured by Freescale. Code Warrior has a built-in simulator [5] that
can be used by the user to debug his or her program code. Code Warrior can support software
debugging via the serial monitor. The necessary electric circuit is connected to microcontroller
board. The board is interfaced with LCD display using Serial Peripheral Interface (SPI).

4. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 6, Issue 1, January (2015), pp. 92- 97© IAEME
95
Fig 1: Normal Gear system
V.2 MECHANICAL UNIT
The gear stick [1] has almost always been placed between the front seats. This space is
therefore occupied and cannot be used for other things. The reason for having the gear stick in this
position [3] is because of the mechanical linkage between the gear stick and the gearbox. This
linkage goes from the bottom end of the gear stick, under the floor, and to a connector on the
gearbox. The gearbox (at least on rear wheel drive cars) is positioned right in front of the gear stick,
under the floor. This makes the placing of the gear stick convenient [7].
This design allows drivers to save wear on the engine by selecting the appropriate gearing.
This mechanical unit has black color with shading. So this can be placed on existing and old lever
operated gear changing vehicles.
Fig 2: Mechanical lever and gear arrangement
V.3 DISPLAY UNIT
The main parts of the SPI are status, control and data registers, shifter logic, baud rate
generator, master/slave control logic, and port control logic. For displaying gear indication, we use
the SPI (Serial Peripheral Interfacing) of microcontroller as shown in Fig.3.

5. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 6, Issue 1, January (2015), pp. 92- 97© IAEME
96
Fig.3 Serial peripheral interfacing (SPI)
VI. THE PROPOSED SOLUTION HAS FOLLOWING MERITS
• By looking at the alarm, a driver can be notified about which gear is currently.
• By interfacing it with the speed of the vehicle, we can alert a driver only if an improper gear
is engaged.
VII. CONCLUSIONS AND FUTURE ENHANCEMENTS
A gear shifter is a fixture in a vehicle which allows the driver to select the gear ratios that are
most appropriate for the speed and conditions. A classic place for the gear lever to mount is at the
center console of the vehicle. The assembly unit is mounted to the gear stick. In a manual
transmission car, drivers have the option of selecting gear ratios with the gear stick. In order to
improve safety and comfort in manual transmission type vehicles we have proposed our “automatic
identification gear position system with electronic controlled method”.
This is an innovative concept. It is a new dimension in the transmission system of a car. This
is a simple and versatile pack. By implementing this system in a car, we can achieve smooth
operation, save fuel consumption, reduce shift jerk and decrease friction in a clutch to controllable
limits. When changing gears, the driver only needs to operate the shifter. An electromechanical or
hydraulic actuator can be used to perform the engaging and disengaging of the cutch. It can relieve
driving effort, making gearshift easier and improve the comfort with respect to a conventional
manual transmission.
VIII. ACKNOWLEDGEMENT
This work forms part of the Research and development activities of Dept of Mechanical
Engineering, Vel Tech Dr RR & Dr SR Technical University, Avadi, Chennai-600062.
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MCU WITH
SPI
MCP3202
ADC

6. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print),
ISSN 0976 – 6359(Online), Volume 6, Issue 1, January (2015), pp. 92- 97© IAEME
97
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