Torque Sensing for Controlled Alternative-Fuel Combustion in Diesel Engines

An analytical and experimental research investigation was performed to evaluate the applicability of various sensor-based torque-measurement schemes to adaptive electronic control systems for diesel engines operating with alternative fuels. Based on analytical considerations, it was determined that the sub-cyclic flywheel speed perturbations which result from local angular accelerations and decelerations induced by the periodic impulsive sub-cycle torque contributions of the individual cylinders of an engine could provide a practical, cost-effective and sufficiently accurate means for torque sensing in both new and existing vehicle configurations. The efficacy of this scheme was experimentally demonstrated on a dynamometer-mounted four-cylinder direct-injection diesel engine through tests in which torque levels predicted on the basis of measured flywheel speed variations were found to be in good agreement with values measured on a reference torque meter under both steady-state and transient engine operating conditions.