MOTRONIC - MED7 “Gasoline Direct Injection” Technology for Reduction of Fuel Consumption and Emissions

Stringent legal requirements and increased demands of automobile manufacturers are the main driving forces for the development of modern electronic Engine Management Systems (EMS). The European automobile industry has voluntarily promised legislators to cut the average carbon dioxide emissions by 25 % for newly registered cars and station wagons by 2008, compared to levels in 1995. Bosch has provided a technical basis to achieve it with Motronic MED7, an electronically controlled EMS for Gasoline Direct Injection (GDI) engines.

The high-pressure GDI system for spark ignition engines is based on a pressure reservoir, which charges a high-pressure pump up to 12 MPa. The gasoline is injected directly into the combustion chamber via fast and precise electro-magnetic valves. Motronic MED7 enables various operating modes of “direct injection”. The strategy is to divide the combustion chamber into two zones; a combustible air/fuel mixture at the spark plug, cushioned in a thermally insulated layer composed of air and residual gas. With this specific stratified charge, the lambda value in the combustion chamber is between 1.5 to 3. Consequently, GDI engine in part loads achieve very low fuel consumption. With increasing engine load, the Motronic MED7 switches over to a homogenous cylinder charge. GDI also increases the power of gasoline engines.

It is expected that by the year 2007 every second new spark ignition engine in Europe will have GDI technology.