Patent ID: 8001767
Filing Date: 2011-08-23
Classification: F02D,F02M,Y02T

Abstract:
1. An engine controller comprising an exhaust purifying device for purifying NOx at an air-fuel ratio richer than stoichiometry, wherein a first combustion region, a second combustion region, and a third combustion region are defined as combustion regions having air-fuel ratios of the mixture gas feeding combustion that sequentially vary from rich to lean, wherein combustion regions are switched from the first combustion region to the third combustion region via the second combustion region, or from the third combustion region to the first combustion region via the second combustion region, the engine controller further comprising: means for estimating the mass of NOx emission downstream of the exhaust purifying device online upon passing of the second combustion region; means for estimating torque variation online upon passing of the second combustion region; and combustion control means for reducing the mass of NOx emission downstream of the exhaust purifying device and the torque variation below predetermined values based on the estimated value of the mass of NOx emission and the estimated value of the torque variation when the second combustion region is passed.