Application of a phase-change heat storage for warming-up the internal combustion engine in a hybrid drive system: Simulations and experiment

In today's automotive industry, the Hybrid Drive System (HDS) is one of the commonly used solutions. The driving conditions of a vehicle in urban traffic mean that the Internal Combustion Engine (ICE), which is part of the drive system, is exposed to work in particularly unfavorable thermal conditions. The low average load of the ICE and the intermittent nature of its operation make it difficult for the cooling system to obtain and maintain the assumed operating temperature of ICE, which increases internal heat losses and fuel consumption. The solution proposed by the authors is the use of a Heat Storage (HS) with Phase Change Material (PCM) in the cooling system of ICE. The heat stored in it is used for warming-up the ICE. In this paper, the authors included a process for selecting selected parameters of the HS in connection with the properties of the HDS. Simulation and experimental results of the solution are presented on the example of the Toyota Yaris Hybrid car. The results obtained both in computer simulations and road tests indicate the possibility of effective heating of the ICE. The differences between the results obtained in simulation and in road tests for ambient temperatures ≥0 °C are insignificant (approx. 6 %) and confirm the correctness of the selection of the heat accumulator parameters.