Development of Transmission Specifications for an Electric Vehicle

Year: 2011
Editor: Chakrabarti, A.
Author: Mahala, K.Manoj; Deb,Anindya
Section: Enabling Technologies & Tools
Page(s): 292-299


At present, a great deal of efforts are on to develop personal modes of transportation such as an electric vehicle (EV) with potentially a higher degree of sustainability as compared to a conventional IC (internal combustion) engine powered vehicle. A transmission system with torque amplification capabilities is essential for an IC engine-based vehicle as, at low rpm, such engines develop extremely low torques which are not sufficient to move a vehicle from rest. However this is not the case for a DC (direct current) motor powered electric vehicle in which the motor intrinsically generates a high torque at rest conditions and delivers maximum power over a wide range of speed which can be well within the operational requirement of a vehicle. Thus,by varying the armature speed of a DC motor with an electronic controller and maintaining a uniform gear ratio, its drivability can be achieved. As most small EVs using DC traction motors are equipped with a single gear transmission system, it may appear that multi-speed gears are redundant for such vehicles. The current study dispels this myth by showing that a two-speed gear box can actually improve the functionality of a DC traction motor-based EV by increasing the rated top speed, initial acceleration and gradeability. In the process,a systematic methodology is developed for estimating traction requirements when a vehicle is propelled into motion from rest and remains in accelerated or steady state conditions subsequently. Together with this, a step-by-step approach has been devised for arriving at the specifications for a two-speed gear box taking into account speed-dependent motor torque and power characteristics.

Keywords: Electric Vehicle, Drivetrain.


Please sign in to your account

This site uses cookies and other tracking technologies to assist with navigation and your ability to provide feedback, analyse your use of our products and services, assist with our promotional and marketing efforts, and provide content from third parties. Privacy Policy.