Description and Operation

Description

Exhaust emissions (CO, HC, NOx) are controlled by a combination of engine modifications and the addition of special control components. Modifications to the combustion chamber, intake manifold, camshaft and ignition system form the basic control system. These elements are integrated into a highly efficient system that controls exhaust emissions while maintaining good drivability and fuel economy. Air-Fuel Ratio Control System [Multi-Point Fuel Injection (MFI) System] The MFI system uses signals from the heated oxygen sensor to activate and control the injector installed in the intake manifold for each cylinder, thereby precisely adjusting the air-fuel ratio and reducing emissions. This, in turn, allows the engine to produce exhaust gases of the proper composition, enabling the use of a three-way catalytic converter. The three-way catalyst is designed to convert the three pollutants [hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOx)] into harmless substances. The MFI system has two operating modes.

1. 1
   The open-loop air-fuel ratio is controlled by information programmed in the ECM.
2. 2
   The closed-loop air-fuel ratio is controlled by the ECM based on information received from the oxygen sensor.