Fuel injection

FUEL INJECTION

Multi-port injection

MEMS, multi-port fuel injection system incorporates four fuel injectors fitted between the pressurised fuel rail and the inlet manifold. Each injector comprises of a solenoid operated needle valve and a specially designed nozzle to ensure good fuel atomisation.

The amount of fuel injected is determined by how long the injector(s) is held open (known as the injector pulse width). To achieve the required air to fuel ratio the ECM receives signals from the following inputs.

1. Crankshaft position sensor (engine speed)
2. Manifold absolute pressure sensor (engine load)
3. Inlet air temperature sensor (inlet air temperature)
4. Coolant temperature sensor (engine temperature)
5. Throttle position sensor (rate of throttle opening)
6. Battery voltage (state of battery charge)
7. Oxygen sensor (oxygen content of exhaust gases)

Further refinement of the fuel to air ratio is achieved by the ECM using the following information:

Battery Voltage Correction

The ECM senses battery voltage and applies adjustments to injector pulse width. These compensate for the effects of any fluctuations in injector pulse widths due to variations in battery voltage.

Over-speed Fuel Cutoff

Above 7000 rev/min, the ECM inhibits the earth path from the injectors. When the engine speed drops to 6990 rev/min, fuel is re-instated to ensure driveability is not impaired.

Idle Air Fuel Ratio

During idle conditions the ECM implements an idle air fuel ratio map. The ECM implements this map when the engine speed is below an idle speed set point.

NOTE: The idle CO is adjustable via the serial port using TestBook.