The amount of exhaust emissions (CO, HC, NOx) is controlled
by a combination of engine modifications and special control components.
The basic system control is composed of the combustion chamber, intake manifold, camshaft and ignition system.
These items are integrated into a highly effective system
which controls exhaust emissions while maintaining good drivability and
fuel economy.
Air/Fuel Mixture Control System [Multiport Fuel Injection (MFI) System]
The MFI system uses signals from the heated oxygen sensor to
activate and control the injector installed in the manifold for each
cylinder, thus precisely regulating the air/fuel mixture ratio and
reducing emissions.
This in turn allows the engine to produce exhaust gases of
the proper composition to permit the optimum use of a three-way
catalyst. The three-way catalyst is designed to convert the three
pollutants (1) hydrocarbons (HC), (2) carbon monoxide (CO), and (3)
oxides of nitrogen (NOx) into harmless substances. There are two
operating modes in the MFI system.
1. |
Open Loop air/fuel ratio is controlled by information programmed into the ECM. |
2. |
Closed Loop air/fuel ratio is adjusted by the ECM based on information supplied by the oxygen sensor. |