INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING AND TECHNOLOGY (IJMET) International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 6340(Print), ISSN 0976 6340 (Print) ISSN 0976 6359 (Online) Volume 6, Issue 1, January (2015), pp. 92-97 IAEME: www.iaeme.com/ijmet.asp Journal Impact Factor (2015): 8.8293 (Calculated by GISI) www.jifactor.com IJMET I A E M E 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 nonprofessional, 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 92
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. 93
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). 94
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. 95
MCU WITH SPI MCP3202 ADC 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. REFERENCES 1. R. P. G. Heath and A. J. Child, Zeroshift, Milton Keynes, 2007, Zeroshift Automated Manual Transmission (AMT), the Automotive Research Association of India, Pune, India, SAE Paper No. 2007-26-061. 2. Peter Händel, 2008, Discounted least-squares gear-shift detection using accelerometer data, IEEE Transactions on Instrumentation and Measurement, Technical report IR-EE-SB, 2008:034. 3. Guihe Qin, Anlin Ge, and Ju-Jang Lee, 2004, Knowledge-Based Gear-Position Decision IEEE transactions on intelligent transportation systems, Vol. 5, No. 2. 4. M. Tideman, M. C. van der Voort, and F. J. A. M. van Houten, 2004, Design and Evaluation of a Virtual Gearshift Application, IEEE Intelligent Vehicles Symposium University of Parma, Parma, Italy. 96
5. Lu Xi, Xu Xiangyang, Liu Yanfang, 2009, Simulation of Gear-shift Algorithm for Automatic Transmission Based on MATLAB, IEEE World Congress on Software Engineering, DOI 10.1109/WCSE.2009.198, 978-0-7695-3570-8/09. 6. Muntaser Momani, Mohammed Abuzalata, Igried Al-Khawaldeh and Hisham Al-M ujafet, 2010, Pneumatic, PLC Controlled, Automotive Gear Shifting Mechanism Maxwell Scientific Organization, Research Journal of Applied Sciences, Engineering and Technology 2(3): 245-251, ISSN: 2040-7467. 7. Matthias Lindner and Thomas Tille, 2009, Design of Highly Integrated Mechatronic Gear Selector Levers for Automotive Shift-By-Wire Systems, IEEE/ASME transactions on Mechatronics. 8. Sunil Dutta, Dinesh Kumar and Pradeep Kumar, 2010 Reliability analysis of defense vehicles gear box assembly under preventive maintenance, Indian Journal of Science and Technology, ISSN: 0974-6846, Vol.3 No.3 9. Kanade Jyoti Suresh and Kulkarni Vishwashri Amrut, A Versatile Microcontroller Based Semiconductor Device Tester International journal of Electronics and Communication Engineering &Technology (IJECET), Volume 5, Issue 2, 2014, pp. 42-49, ISSN Print: 0976-6464, ISSN Online: 0976 6472. 10. Mahesh Sharma and K. Singh, Automated Testing of Ni-Cd Batteries Using Microcontroller Based Charge-Discharge System International Journal of Electrical Engineering & Technology (IJEET), Volume 5, Issue 5, 2014, pp. 28-35, ISSN Print: 0976-6545, ISSN Online: 0976-6553. 11. Maha M. Lashin, A Metal Detector Mobile Robot As A New Application of Microcontroller International journal of Computer Engineering & Technology (IJCET), Volume 5, Issue 7, 2014, pp. 24-35, ISSN Print: 0976 6367, ISSN Online: 0976 6375. 97