Abstract
The main reason for the disadvantages in part load efficiency of gasoline engines in comparison to diesel engines is the pumping work due to the throttle control. A promising concept to prevent pumping losses is the load control by variable valve timing . By this the air mass is controlled by the valve timing of the intake valves without changes in the air density. Investigations of this concept show advantages in fuel consumption in comparison to modern series engines of greater than 15%.
The flexibility of such a system implies its higher complexity. The camshaft is replaced by a system of actuators, driving units and a control system. To take full advantage of the thermodynamic principle, the system components and especially their interactions have to be optimized. The integration of thermodynamics, mechatronics and the vehicle electrical system makes it a new dimension in engine controls.
The paper gives an overview of the thermodynamic motivation, the basic system structure and the operation principle of the actuator. It shows additionally some more detailed examples of aspects like ECU function development, mechatronical simulation, rapid prototyping of closed loop control strategies of the mechatronical actuators and the simulation of the vehicle electrical system.