Actuator torque optimization of an automotive thermal management mechatronic valve based on a hydro-mechanical modelling and experimental validation

Oil is the world's first energy resource as it satisfies 32% of energy needs. It is the most used energy resource in transportation with more than 90% of the final energy consumption. Since several years, improving fuel economy and reducing the Greenhouse-Gas (GHG) emissions have been the determining factors in the development and implementation of innovative automotive technologies that improves efficiency without compromising emissions and costs. Engine thermal management is a one of the research fields that tries to solve this issue. It can be done by controlling temperatures in different cooling circuits with an electronically controlled valve, which respect certain thermal management strategies in which the control varies depending on several parameters such as temperature, load and the engine speed. Designed by MANN+HUMMEL, the ACT valve (Active Cooling thermal management valve) is mainly composed of a rotating cylindrical cam driving by a DC-actuator. It controls, accurately, the distribution and flow of the coolant in different branches of the cooling circuit including the engine and the interior heating/cooling system through valves that manage the opening and closing of branches. This paper is part of a larger work that aims to improve the robustness of the ACT valve design process since the early steps while minimizing the torque requirements of the DC-actuator. Taking into account the multi-physical constraints of the functioning environment such as water regain, mechanical load, fatigue, wear and clearances, but also of manufacturing constraints and process and geometrical tolerances related to the injection of thermoplastic parts. So in order to qualify the design process as robust, these uncertainties must be taken into account from the design phase to ensure the effectiveness and reliability of this valve over its life time. In this paper, we focus on a new hydro-mechanical model which is composed of four different sub-models that has been developed in order to simulate the multi-physical environment and so was validated based on experimental data. The output that interests us the most is the torque required for the cam rotation because its maximum value corresponds to the torque requirement of the DC-Actuator. This model was used to illustrate the cam resistive torque sensitivity to certain geometrical parameters, these computed sensitivity analyses are compared in to those obtained with the experimental way. Once validated the model is then used in a particle swarm based optimization (PSO) process which helps to determine a robust optimal geometric configuration. This work helped to ensure the effectiveness and reliability of this valve over its life time, first by developing a multi-physical core model then by experimentally validating the model capacity to predict new design suggestions based on a particle swarm based optimization (PSO) loop results applied on the model. The next step will be to evaluate experimentally the geometric configuration recommendations of the optimization algorithm then to seek ways to integrate these new configurations in the design process