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The main targets concerning development activities for diesel engines are defined by future exhaust gas legislations (EURO IV, V). Due to the conflict between particulate and NOx emissions, both components of the exhaust gas are limited: The combination of direct injection of diesel into the combustion bowl and limited adoption of air swirl causes locally fuel-rich regions which lead to soot and burn at high peak temperatures in stoichometric regions. Simultaneously, the transient drive-off torque and the maximum power output are limited due to the time which is necessary for the mixture formation process. By means of intensified flow energy and a demand-oriented regulation of the air mass flow using an impulse charging device for diesel engines, locally fuel rich regions inside the combustion bowl can be minimized which finally influences the NOx-Soot Trade-Off by inside-engine measures and improves low-end torque and power characteristics.

A variable valve actuation mechanism suitable to activate and deactivate the intake and exhaust valves of reciprocating engines will be presented within this paper. This system called the “CVD System” (Cylinder and Valve Deactivation) allows a reliable activation and deactivation of the valves of conventional cam-controlled valve trains within one engine cycle, independent of the oil feeding system. The system can be used for both the deactivation of single valves of multi-valve engines - e.g. to increase the in-cylinder charge motion - or the deactivation of complete cylinders of multi-cylinder engines. Different to the well known hydraulic valve shifting or switching devices the CVD system represents an electromechanical device with an unlocked (deactivated) position being mechanically offered to a solenoid operated coupling lever once per cam revolution. If valve deactivation is required the solenoid is switched on to cut the force line between cam and valve.