Spark-ignition engines closed-loop control (SIECC)

As the spark ignition engines highest efficiency is obtained at knock borderline, more than any aspects in these engines, attentions have been and being paid to identification of this undesired complex phenomenon (knock) and its borderline, and to control the engine operating conditions to avoid it. Fuel economy, engine performance optimization problems are also greatly depend on this borderline control. As a realistic engineering solution, in the current work, the engine cylinder pressure and temperature and composition of the fuel are used as inputs to an online closed loop control system to perform the identification of knock borderline. The loop actuating signal will then adjust the engine variables to maintain the engine performance by the borderline. The experimental part of the study was conducted in the University of Bradford Engine Laboratory (UK). Cylinder pressure data were obtained at 24 to 72 KHz sampling frequency from a variable compression ratio research engine (Ricardo E6)