Estimation of Combustion Information by Crankshaft Torque Sensing in an Internal Combustion Engine

Future emission regulations for internal combustion engines as well as a strive to reduce CO₂ emissions has lead to an increasing interest in control of the combustion process in order to maximize efficiency while keeping the emission levels at a minimum. One possibility to indirectly measure the combustion process quality is by using a crankshaft mounted torque sensor. A signal processing technique is outlined which provides estimates of the gas torque from individual cylinders based on data from a crankshaft mounted torque sensor. The estimates are used for closed loop ignition timing control for the purpose of maximizing engine efficiency. Results from three tests are reported and the presented technique results in a reduced fuel consumption.