Critical aspects on the control in the low temperature combustion systems for high performance DI Diesel engines

The present paper describes one of the Low Temperature Combustion (LTC) management philosophies, today under development for application to Diesel engines, showing and analysing some critical aspects deriving from its use. In particular, starting from the analysis of the application of LTC to a four-cylinder Diesel engine, at the state of the art of current technology, the emission performance for LTC and conventional Diesel combustion are compared, together with the constraint in the application of LTC to the limited low load-low speed range. Moreover, the problems relative to different air/fuel feeding for each cylinder, knocking, torque drop and high smoking event during transient conditions, different actuation velocity of the components (of injection, turbo, EGR and swirl control systems) during the switch between LTC and conventional combustion, are presented and critically commented, indicating the main research drivelines for practical application.