Search Results

In order to maximise engine efficiency it is of interest to find the peak pressure position (PPP) of the cylinder pressure when controlling combustion engines. Cylinder mounted pressure sensors can be used to measure the pressure, but these are expensive and suffer from limited durability. Alternative pressure estimation methods using cheaper and more durable sensors are needed. This paper shows the performance when estimating the cylinder pressure of a five cylinder SI-engine using a crankshaft integrated torque sensor. An engine model is constructed to be able to eliminate the torsional resonances in the sensed torque signal and the cylinder pressure is reconstructed using a parameterised pressure model. The performance of the estimator is studied in three different simulation cases. Finally, the performance based on measured torque is presented.

Feedback control of combustion phasing based on a crankshaft integrated torque sensor was developed for a spark ignited five cylinder engine. A cylinder individual measure for combustion phasing, called 50% torque ratio, is extracted from the torque signal and used by a spark advance controller. The estimated torque ratio is based on a simplified estimation algorithm where torsional resonances in the crankshaft are neglected, thus limiting the operating range up to a maximum of about 2000 rpm. The torque ratio measure has been compared with the existing measure 50% burned mass fraction, and proven to be a reliable measure for combustion phasing. The spark advance controller has been evaluated by using internal EGR changes as combustion disturbances and an examination of its cylinder balancing properties was performed.