•  The PCM controls fuel injection timing by driving the TCV mounted to the injection pump by modifying the hydraulic pressure applied to the timer piston and by moving the position of the timer piston.

•  The PCM calculates the target fuel injection amount based on input signals, and determines the opening angle of the timer control valve according to this calculation.

•  The TCV is driven by the duty signal sent from the PCM. The longer the duty signal is ON, the more the valve opens, and injection timing also becomes faster.

•  Basic fuel injection timing is pre‐programmed into the PCM and is determined by engine speed and fuel injection amount.

•  A correction value suitable for starting is pre‐programmed into the PCM and is determined by engine speed and engine coolant temperature.

•  A correction value suitable for driving is pre‐programmed into the PCM and is determined by engine speed and engine coolant temperature.

•  The target timer piston position is calculated from fuel injection timing calculated in the PCM.

•  TCV drive control performs feedback control by sending a duty signal to the TCV to make the actual timer position approach the target timer position.