Real-time combustion torque estimation on a diesel engine test bench using an adaptive Fourier basis decomposition

We propose an estimator of the combustion torque on a diesel engine using as only sensor the easily available instantaneous crankshaft angle speed. The observer consists in an adaptive filter on the coefficients on the Fourier basis decomposition designed on a physics-based time-varying model for the engine dynamics. Convergence is proven, using a Lyapounov function in both continuous and discrete cases. A test bench and development environment is presented. Performance is studied through simulations and real test bench experiments. Specific features of this observer are: a combustion model free dynamics expressed in angular time, and phase shift free reconstruction of the mass torque.