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2-speed automatic transmission controller for electric vehicles
Published:
February 6, 2023
Category:
Case Study
Background
Automobile sector is changing rapidly as electric vehicles playing a vital role in the industry. So many advancements in technology and engineering are taking place. Transmission systems of the vehicles are also evolving day by day. Only automatic transmission is used in the electric vehicles as the speed variations are less and it gives comfort to driving the vehicle. The control of the automatic transmission is necessary to attain smoother shifting, leading to better drivability.
The client has one of the largest after-market networks serving the industrial and automotive markets and making advances in the area of electric mobility. They developed a two-speed automatic gearbox system for electric vehicles coupled with the motor. A controller was required to control the automatic transmission and hence improve the efficiency of the electric motor by automatically selecting the right gear as per the vehicle speed. Two-speed automatic transmission with the controller completes the Transmission Control Unit (TCU) which governing automation of gear-shifting process in the transmission system.
The company is on the mission of contributing to making motion and mobility more efficient, intelligent and sustainable. They approached Intrinsig solutions for the hardware and software development of the transmission controller as they are prioritizing the local design and development of EV-related solutions, given the growing market of electric vehicles across the country. This system has lived up to the expectations of acquiring higher transmission efficiency at high gears, which makes it a promising prospect.
Solutions
Intrinsig worked closely with the company’s team to design and develop the transmission controller for the two-speed automatic gearbox system which is called the Transmission Control Unit (TCU). The new technology improves the efficiency of electric DC motor, by automatically selecting the right gear as per vehicle speed.
Intrinsig team developed a prototype after the functional review of the two-speed auto-shifting transmission system. The transmission control unit uses sensors from the vehicle and reads the information provided by engine control unit (ECU) and transmits the vehicle speed, and other inputs such as motor current sensor value, clutch position and throttle position via standard CAN bus protocol. The read parameters are processed in the algorithm that decides the best gear ratio for the given operating conditions, therefore can optimize the overall motor efficiency and increase the performance of the electric vehicles. The TCU is mounted in-line with the electric motor.
Also, Intrinsig focused on fault management and implemented Design Failure Modes and Effects Analysis (DFMEA) to the two-speed automatic transmission system. This approach helped to identify the possible risks, failure modes and their effects on the system. In case of fault, transmission controller calibrates the sensors and sends the signal to vehicle control unit (VCU). UART protocol is used for the diagnostics of faults.
Benefits
- Improvement in the working efficiency of the motor.
- Reduction in the energy consumption of vehicles.
- Better vehicle’s acceleration performance and climbing ability.
- Fault diagnosis and management system makes it a reliable system.
