Crank-Angle Based Control of High Speed Diesel Engines

The diesel engine can be viewed as a discrete system. Modem electronically controlled injection systems, such as the Lucas EPIC pump, are synchronised to the torque cycle with one sample per fire. Thus the sample interval decreases with increasing engine speed. Linear phenomena such as drivetrain resonances become nonlinear in the crank-angle (sampling) domain. We derive a discrete linear crank-domain model for the engine whose parameters are related to time-domain properties and vary with engine speed. This model is verified by simulation. The successful application of the model to real engine data for system identification and control design is discussed.