Modern diesel engines are facing highly restrictive demands regarding efficiency and emissions. In order to meet these demands, the complexity of the engines and their control systems is increasing rapidly. Because of this, the task of calibrating traditional open-loop engine control systems is quickly becoming overwhelming and therefore the interest in closed-loop control is growing. Also, the concept of closed-loop control provides higher accuracy and robustness compared to open-loop control. These properties are needed in order to enable the use of more efficient combustion concepts.
Closed-loop control systems rely on accurate information about the controlled process. In this case the controlled process is the combustion within the cylinders of a light-duty diesel engine and combustion information is thus a necessity. This information can be provided by a number of different sensors, the most common being in-cylinder pressure sensors. As alternatives to these sensors, this project investigates the use of information from crankshaft torque and ion current measurements for closed-loop diesel engine control. A large portion of the work therefore consists of developing methods for extracting combustion information from the measured signals.
Project time: 2007-2012