Electric Feed Pump Simulation and Control for Fuel Saving and System Cost Reduction

摘要

Current market drivers for automotive and light commercial engines and powertrain systems are mainly the new CO_2 emission regulations all over the world and the pollutant emission reduction in the emerging markets, at minimal system cost. For both reasons, the adoption of a regulated electric low pressure fuel pump is very advantageous for electronically controlled diesel systems, customized for the emerging markets. Usually, the fuel delivery from the feed pump is performed at the maximum flow rate and a pressure regulator discharges the exceeding fuel amount either from the rail or upstream the high pressure pump. Therefore, at part load, the electric feed pump flow is higher than the request for engine power generation. For the purpose of this paper, the low pressure fuel pump is controlled for fuel delivery according to the engine request (reduced fuel consumption), thus avoiding the use of a pressure regulator valve (reduced cost). The development of the system was carried out with an SIL approach, by simulating the performance of the ECU control on a validated plant model, thus also reducing the costs related to engine testing. The performance of the rail pressure control was compared to the state-of-the-art systems. A sensitivity analysis to system parameters dispersion was also carried out, to verify the feasibility on actual system and the constraints. Then, the control was tested at the engine bench for a preliminary tuning and evaluation of the fuel saving.