In this work, fuzzy second-order sliding mode control (2-SMC) and adaptive sliding mode control (ASMC) are developed for a turbocharged diesel engine (TDE). In control design, the TDE is represented by multi-output multi-input (MIMO) nonlinear model with partially unknown dynamics. To regulate the intake manifold pressure, the exhaust manifold pressure, the compressor flow, and to estimate the unknown functions, a sliding mode control (SMC) combined with fuzzy logic is first developed. Second to reduce the chattering phenomenon without deteriorating the tracking performance, two approaches are investigated. A special case of the 2-SMC: the super-twisting SMC is developed. The results obtained using the ASMC are also presented to compare the performances of both methods. All parameter adaptive laws and robustifying control terms are derived based on Lyapunov stability analysis, so that convergence to zero of tracking errors and boundedness of all signals in the closed-loop system are guaranteed. Simulation results are given to show the efficiency of the proposed approaches.