Engine synchronous sensor processing in the transmission control unit

Abstract

The electronic control units (ECUs) of the modern-day vehicle have evolved significantly over the years, with the increasing range of sensors used. Some of the sensors in the transmission ECU of a conventional diesel truck, such as the inclination sensor and the clutch position sensor, are affected by the vibrations caused by engine rotation, which can result in noisy sensor measurements. The purpose of this master thesis project is to collect sensor information synchronous to the engine rotation in the transmission ECU, in order to filter out the engine vibration from the raw sensor measurements, resulting in better vehicle control. We evaluate the possibility of engine-synchronous sensor acquisition by developing a proof of concept method to communicate the engine-synchronous signal from the engine ECU to the transmission ECU. The two communication methods identified and explored are, first, the dedicated direct-line communication method and, second, the controller area network (CAN) communication method which were implemented in a test-rig setup. An engine-synchronous signal transmitted using the direct-line communication was then used to schedule the filtering software at the transmission control unit for an inclination sensor to filter the vibration noise from the raw inclination sensor values using a simple moving average filter. The developed the synchronous filtering was also implemented and tested on a moving truck and the results were analysed. We were able to transmit a signal engine-synchronously from the engine ECU to the transmission ECU by using the direct-line communication method. This signal was used to engine-synchronously filter the sensor noise using a simple moving average filter in the transmission control unit.