Motronic MED7 for Gasoline Direct Injection Engines: Engine Management System and Calibration Procedures 1999-01-1284
This paper describes the main strategies of the advanced Motronic MED7 engine management system for gasoline direct injection. This concept supports all required operation modes e.g. stratified, homogeneous lean and semi stratified to meet the highest fuel savings provided by the customers GDI combustion concept. Coordinated with Bosch GDI-components this system offers the highest performance for the future emission standards ULEV, EUIII and EUIV and meets all EOBD-requirements. The main structure of this system is based on the engine torque and is coordinating all activities via torque and efficiencies. The different operating modes are coordinated by a special dynamic mode manager, which is able to select the optimal operating mode under all conditions. The aftertreatment concept is based on an exhaust catalyst system comprising a fast heated pre-catalyst for early HC-reduction and a main catalyst with a NOx-adsorber anda TWC. Three sensors are necessary to allow the optimal control of this aftertreatment system. The MED7 is using an extended diagnosis concept, which is monitoring not only the intake air-path but also the fuel-path. The scheduling of all important diagnosis functions is done by a new diagnosis system manager, which offers an advantage with a dynamic structure for easy calibration. The procedure of the calibration has been newly developed to save calibration time and to give a better understanding of the physical behaviour of a GDI-engine.