Real-Time Back Torque Measurement Using Contactless Telemetry on Electric Starter System of a Two-Wheeler Fired Engine

In a two-wheeler, electric starter system generally One way clutch is coupled with the magneto rotor. This allows the transfer of torque from the electric motor to the magneto rotor and finally to the crankshaft to start the internal combustion engine. After the electric starter, has started the internal combustion engine, one way clutch automatically goes into idling mode. In two-wheeler, internal combustion engine is susceptible to misfire due to variations in combustion behavior. This sometimes leads to knocking and unpredictably high back torque. This acts on the starter system and leads to failure of One way clutch, starter gears or the starter motor. It is not feasible to predict the back torque realistically. It is also very challenging to make real time measurement of back torque on the fired engine. In this paper, we are attempting to explain a unique testing methodology which was adopted to overcome this challenge and successfully measure the back torque accurately. The instrumented test vehicle was mounted on a chassis dynamometer. Back torque was simulated using specific test cycle. The measurement was carried out with the help of instrumented magneto rotor using strain gauges as torque sensing elements. For sensing the torque signal, telemetry system was used and for data logging Rotec system was used. Telemetry sensor was fixed onto the extended crankshaft and the receiver was mounted onto a housing. Torque signal was measured from instrumented magneto rotor with Strain gauges. Signals received from strain gauges were amplified and logged into Rotec DAC system and were further analyzed with Rotec software. The crankshaft speed was also measured with the help of optical speed sensor. Back torque was analyzed with respect to the crankshaft speed. Thus, this measurement resulted in thorough understanding of the back torque in two-wheeler internal combustion engine.