Transient Burned Gas Rate Control on VVA equipped Diesel Engines

This paper addresses the problem of cylinder burned gas rate transient control of VVA equipped Diesel engines. This problem is of importance for NOx emissions reduction. The proposed strategy coordinates existing low-level intake manifold burned gas rate and VVA controllers. To determine relevant control actions, a model of cylinder filling phenomenon is determined. It expresses, under the form of a discrete event dynamics, the behavior of the cylinder burned gas rate at intake valve closure. Interestingly, the model is invertible, thanks to its analytical nature. This property directly suggests an inverse formula that serves as control law. The strategy is efficient as is highlighted by experimental results obtained on a 1.6 L Diesel engine test bench. As a result, NOx emissions are largely diminished during transients.