Pressure-based transient intake manifold temperature reconstruction in Diesel engines

Temperature measurements by the typical thermocouples contain some first-order dynamics with varying time-constants and need to be reconstructed in transient conditions for improving the accuracy of the temperature information. Particularly, for Diesel engine advanced combustion mode control, the accurate acquisitions of the rapidly varying transient temperatures, such as the intake manifold gas temperature, are of importance. In this paper, a temperature reconstruction method, without using additional sensors, is proposed by utilizing the counterpart pressure signal. Through investigating the thermocouple dynamics in terms of the intake manifold pressure and temperature, an intake manifold temperature model was derived. According to this proposed temperature model, the transient temperature reconstruction can be formulated as a thermocouple time-constant estimation problem. Within this framework, an extended Kalman filter (EKF) based method was devised for the parameter estimations. The proposed method was validated through high-fidelity GT-Power engine model simulations as well as experimental results obtained on a multi-cylinder medium-duty Diesel engine.