In this paper a combustion model of Direct Injection Diesel engine is proposed to calculate the in-cylinder pressure and a crank-slider mechanism model to calculate instantaneous indicated torque. The crankshaft is modelled as a rigid body. The parameters of both models are identified via non-linear least square optimization algorithm. The data, used for the identification procedure, are purposely obtained through experiments on a diesel turbocharged BMW MD47 1900cc with a dynamic test-bench.