Fuel Injection Control

The fuel pressure applied to the fuel injector by the fuel pump is constant relative to the intake manifold pressure by the pressure regulator. The injection fuel amount is determined by the injector operation time.
Injector operation time is determined by adding several compensations to the basic injection time which is calculated on the basis of the intake air volume and engine speed. The information of the intake air volume and that of the engine speed are sent to the ECM from the air flow meter and the ignition coil respectively in the form of electrical signals.
Under this system, the air/fuel ratio is controlled to optimum air/fuel ratio by using the oxygen sensor information. The compensation is as follows:
Warm-Up Enrichment Compensation--during cold engine operation, the air/fuel ratio is adjusted to compensate for coolant temperature.
Starting Enrichment Compensation--improves starting performance.
After Start Enrichment Compensation--maintains engine speed ability after engine start. This compensation gradually decreases according to engine speed.
Acceleration Enrichment Compensation--compensates for engine load during acceleration during warm-up.
After Start Acceleration Enrichment Compensation--Compensates for engine load during acceleration immediately after engine start. This compensation gradually diminishes in proportion to the increase in coolant temperature.
Power Enrichment Compensation--Compensates for high engine loads.
Battery Voltage Compensation--Compensates for injector operation delay time.
Inlet Air Temperature Compensation--Inlet air volume is compensated for depending on its temperature.
Air/Fuel Ratio Compensation--Adjusts air/fuel ratio to its optimum value according to information from the oxygen sensor according to the need of the three-way catalytic converter.
Base Air/Fuel Ratio Compensation--Adjusts air/fuel ratio to its optimum value according to information from the oxygen sensor to compensate for altitude change or barometric pressure change.
Fuel Cut--Fuel cut is implemented during deceleration to reduce HC emissions by stopping injector operation.