Compensation Injection Time Compensation Injection is also known as “speed up”. It detects the working condition and load of the engine at that time by various sensors, and sends the signal to the computer (ECU) to calculate the required additional fuel supply. It is used to maintain the stable and smooth operation of the engine. The setting of the compensation injection program is a complicated work, and it also varies from vehicle to vehicle. Generally speaking, the compensation injection programs generally have the following items: cold car start compensation, warm car compensation, start compensation after idling, high temperature compensation, acceleration compensation, high speed/high load compensation, theoretical air-to-fuel ratio feedback compensation, fuel cut-off control. Invalid injection time There will be a delay time between the coil energization and full fuel injection of the injector, which is called “opening delay”, and there is also a delay time after the coil is powered off to the complete stop of fuel injection, which is called “closing delay”. Since the opening delay time is greater than the closing delay time, the actual fuel supply will be less than required, and the opening delay time minus the closing delay time is called “ineffective injection time”.