· Easy switching from CNG to gasoline power

· Great potential for reduction of untreated emissions

Bosch has developed a comprehensive engine management system specifically geared to bivalent vehicles which can be alternately powered by gasoline or compressed natural gas (CNG). With ever increasing prices for gasoline and diesel fuels, alternative drive systems are becoming more attractive for drivers. Compressed natural gas is a useable alternative already today. And for very good reasons: CNG is produced without sophisticated refining, its combustion generates a very low degree of emissions, i.e. compared to a gasoline engine, the combustion of CNG produces 25 percent less carbon dioxide. The exhaust fumes, furthermore, do not contain any particulates and are odorless. The CNG engine management system production will be starting in 2006.

The Bosch system for bivalent CNG and gasoline operation consists of an engine control unit, components for fuel supply and mixture formation as well as the required sensors. The Bi-Fuel System from Bosch allows switching from gasoline to CNG operation while driving without interrupting the power output of the combustion engine. The center piece of the system designed by Bosch is the Bi-Fuel control unit NG-Motronic, which is based on the engine management for gasoline injection. Integrating both fuel systems in one single ECU saves costs and reduces the wiring and cable connections in the vehicle.

Bosch developed the Natural Gas Injector NGI 2 specifically for the requirements of blowing in natural gas. The injector has a specific lining and is especially suited for operation with oil free gas. In its outer dimensions, NGI 2 corresponds to the usual gasoline injectors from Bosch and can thus be integrated into existing systems without problems.

In future, CNG power will offer even greater potential: the high knock-resistance of compressed natural gas makes it an ideal candidate for combustion engines with performance enhancing supercharging. This provides development potential for downsizing concepts, which are the basis for designing engines of lower displacement with higher degree of efficiency and performance rating similar to stronger ones.

PI5014 - September 2005