Abstract: Modern diesel passenger cars already fulfll high demands regarding the reduction in NO_x emissions through complex exhaust aftertreatment systems. With the consideration of real driving emissions, the reduction in NO_x emissions in high transient engine operation becomes even more challenging. Apart from increasing the complexity of exhaust aftertreatment systems, internal engine measures play a major role. The approach to reducing NO_x emissions described in this paper uses the precise control of the combustion. For this purpose, the method of digital combustion rate shaping control is applied, which allows the realization of a predefned combustion by automatically adapting the injection profle during operation. Within this work, this controller is extended in order to control the predefned combustion trace based on target NO_x values. First, the working principal of the state-of-the-art digital combusting rate shaping controller is explained. In the next step, the design and strategy of the extended control approach are explained and validated. Finally, its potential to reduce engine-out NO_x emissions during transient driving situations is evaluated based on simulations of the WLTC. It is shown that the control concept fulflls the requirements and is able to efectively reduce high NO_x peaks during transient operation.

Key words: Diesel engine , · Emission control , · Combustion rate shaping , · Closed loop combustion control , · NO_x , Control ,