Technical Paper
The Development of the GM 2.2LCNG BI-Fuel Passenger Cars
1998-10-19
982445
A CNG bi-fuel version of the Chevrolet Cavalier has been developed as an OEM (Original Equipment Manufacturer) vehicle. The fuel management system is an automatically switching bi-fuel system which is able to control fuel flow rate, spark timing, EGR, and perform OBD-II (On-Board Diagnostics II). The system consists of a CNG fuel tank, fuel filter, electric and manual fuel shutoff valves, high and low pressure regulators, gas mass sensor, mixture control valve, gas distribution system, CNG fuel gauge, OEM exhaust gas oxygen sensor, digital engine control unit (ECU), OEM powertrain control module (PCM) and unique wiring harness. This paper discusses the components, operation, and calibration of the CNG bi-fuel management system. A computer engine simulation model able to predict engine performance, fuel economy, and exhaust emissions, was used to assist spark, fuel, and EGR table mapping.
