Combustion torque estimation utilizing smoothed implicit derivatives from crank sensor samples

This paper presents a torque estimation method for a reciprocating engine from crank sensor signals. The method calculates angular velocity and acceleration of an engine crankshaft utilizing smoothed implicit derivatives from crank sensor samples. Then crankshaft torque is calculated through the motion equations of an engine. Combustion torque, which contains useful information for engine control, is estimated from the crankshaft torque by using the property of specific points in the equations of motion. Estimation results for measurement data confirm the ability of the method to estimate combustion torque in practical.