7.4 Driveline Speed Control

The background and problems with traditional diesel engine speed control (RQV) were covered in Section 7.3. Driveline speed control is here defined as the extension of RQV control with engine controlled active damping of driveline resonances. Active damping is obtained by using a feedback law that calculates the fuel amount so that the engine inertia works in the opposite direction of the oscillations, at the same time as the desired speed is obtained. The calculated fuel amount is a function of the engine speed, the wheel speed, and the drive-shaft torsion, which are states of the Drive-shaft model, derived in Section 7.1. These variables are estimated by a Kalman filter with either the engine speed or the wheel speed as input. The feedback law is designed by deriving a criterion in which the control problem is given a mathematical formulation.

The RQV control scheme gives a specific character to the driving feeling e.g., when going uphill and downhill. This driving character is possible to maintain when extending RQV control with active damping. Traditional RQV control is further explained in Section 7.4.1. Thereafter, the speed control problem keeping RQV characteristics is formulated in Section 7.4.2. The problem formulation is then studied in the following sections. The design based on the Drive-shaft model is simulated together with the more complicated Nonlinear clutch and drive-shaft model as vehicle model. Some important disturbances are simulated that are difficult to generate in systematic ways in real experiments. Finally,...