Optimal control of a fuel-fired auxiliary heater for an improved passenger vehicle warm-up

In order to mitigate the comfort problems during a vehicle warm-up, the vehicles propelled by high-efficiency engines are increasingly equipped with auxiliary heaters. Although the usage of an auxiliary heater improves engine efficiency during warm-up, a higher total fuel consumption results in general. In this paper, an optimal, model-based feedback control law for the optimal operation of a fuel-fired heater with respect to passenger comfort and fuel economy is derived. To this end, a control-oriented mathematical model of the system is established, calibrated, and validated. Based on this model, an optimal control problem is formulated and solved. In simulation studies, the functionality of the resulting optimal controller is demonstrated, and its superiority to the state-of-the-art control laws is assessed.