Circuit/System Description
The engine control module (ECM) supplies a high voltage supply circuit and a high voltage control circuit for each fuel injector. The injector high voltage supply circuit and the high voltage control circuit are both controlled by the ECM. The ECM energizes each fuel injector by grounding the control circuit and supplying each fuel injector with up to 250 V and 20 A on the voltage supply circuit to activate the Piezo type fuel injectors. This is controlled by boost capacitors in the ECM. During the 250 V boost phase, the capacitor is used to charge the injector piezo stack, allowing for injector opening. The injector is then held open with this high voltage. At the end of the injection event the ECM closes the injector by discharging the injector piezo stack. The ECM monitors the status of the voltage supply and voltage control circuits. The injectors are separated into the following four groups:
- Group 1- injectors 1 and 4
- Group 2- injectors 2 and 3
When a fuel injector circuit fault condition is detected by the ECM, the specific fuel injector or the two fuel injectors in the affected group may be disabled.