Search Results

Current market drivers for automotive and light commercial engines and powertrain systems are mainly the new CO2 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 increasing request for pollutant emissions reduction spawned a great deal of research in the field of innovative combustion methodologies, that allow obtaining a significant reduction both in particulate matter and NOx emissions. Unfortunately, due to their nature, these innovative combustion strategies are very sensitive to in-cylinder thermal conditions. Therefore, in order to obtain a stable combustion, a closed-loop combustion control methodology is needed. Prior research has demonstrated that a closed-loop combustion control strategy can be based on the real-time analysis of in-cylinder pressure trace, that provides important information about the combustion process, such as Start (SOC) and Center of combustion (CA50), pressure peak location and torque delivered by each cylinder. Nevertheless, cylinder pressure sensors on-board installation is still uncommon, due to problems related to unsatisfactory measurement long term reliability and cost.