The goal of minimizing CO2 emissions in internal combustion engines requires an optimized tuning of the individual system components. To optimize the internal combustion engine-turbocharger system, a hardware-in-the-loop method is being developed to simulate engine operation on a hot gas test bench.
The continuous tightening of CO2 emissions legislation requires a constant evolution of internal combustion engines. One technology for reducing engine CO2 emissions is downsizing, which involves reducing the cylinder volume or the number of cylinders to decrease weight and friction losses. To compensate for the resulting power deficit, turbocharging via exhaust gas turbochargers is employed. This allows for the further utilization of energy remaining in the exhaust gas, thereby increasing the engine's efficiency additionally.
A development challenge lies in the efficiency of the internal combustion engine-turbocharger system. Due to the transient operation of internal combustion engines, exhaust gas pulsations occur, which are not optimal for the continuous operation of a turbocharger at its efficiency optimum in a given operating point. This challenge must be addressed through the optimal tuning of the turbocharger to the engine operation.
The aim of the project is to develop a hardware-in-the-loop method that can be used to simulate engine operation on a turbocharger hot gas test bench. This allows for the optimization of the turbocharger for a specific engine in early development stages when the engine is not yet available as hardware.
In the first step, the engine map of a turbocharged gasoline engine is measured on a test bench. Based on the measurement data, a predictive 1D simulation model of the engine is validated and simplified into a real-time model. This real-time model is then coupled to a hot gas test bench and provides the engine boundary conditions for applying the turbocharger with the exhaust gas pulsations from engine operation. The conversion into real pulsations is achieved through the control of a rotating flap based on the real-time engine model.
In the final step, an equivalent representation of the turbocharger map limits in real engine operation and in the developed method should be demonstrated. In a potential follow-up project, this method can then be expanded and optimized for further systems.