A New Development of Internal Combustion Engine Air-Fuel Ratio Control With Second-Order Sliding Mode

A novel application of a second-order sliding mode control (SMC) scheme to the air-fuel ratio (AFR) control of automobile internal combustion engines is developed in this paper. In this scheme, the sliding surface $S[x(t)]$ is steered to zero in finite time by using the discontinuous first-order derivative of a control variable $u̇c(t)$⁠, and the corresponding actual control variable $uc(t)$ turns out to be continuous, which significantly reduces the undesired chattering. Its sliding gain is adjusted by a novel radial basis function network based adaptation method derived using the Lyapunov theory. It not only avoids handling the unavailable parameters and variables, but also saves the unnecessary manual adjusting time of the second-order SMC. The proposed method is applied to a widely used engine benchmark, the mean value engine model for evaluation. The simulation results show substantially improved AFR control performance compared with the conventional SMC.