The control system was also tested for conditions of variable engine speed and torque in order to attempt to simulate conditions closer to real traffic. The combinations of engine speed and torque which were applied, referenced hereafter as Cycle 1 and Cycle 2, are presented in Fig. 6(a) and (b), respectively. The control system’s behaviour, represented in terms of control valve opening and generator temperature, is presented in Fig. 7(a) and (b), while the cooling of the refrigerator is shown in Fig. 8.