In order to meet the demands of the Peak & Hold drive mode for the current decline rate in the solenoid current release stage

the design and performance of a new common rail injector variable freewheeling drive circuitry were studied. To this end

a high side and low side MOS scheme and a single power supply drive mode were adopted in the circuit design. The high side MOS power supply electrode was provided with a reverse diode and capacitance grounding

and the low side MOS drain electrode was set with a diode connected drive power supply. The different effective freewheeling circuits were used to decide the current decline rate to satisfy the demands of Peak & Hold by changing the switching logic of high side and low side MOS in different stages. Results show that compared with the traditional RD freewheeling (R=10 Ω) circuitry

the new design can improve the control precision of variable freewheeling fuel injection quantity. The injector closing time can be shortened by 30 μs

and the injection cycle change rate reduced by 0.36% in a large amount of fuel

while in the small amount of fuel reduced by 2.86%. Moreover

in the current closing stage

the injector can be used to release the electromagnetic energy to the drive power supply

so that the fuel injector solenoid drive energy consumption is reduced. This allows reducing the voltage drop of drive power supply and the recovery time by 1.5 V and 0.5 ms respectively in a large amount of fuel. Since the heat release of the circuit is reduced due to the reduction of energy consumption

the maximum is only 37 ℃

which is 127 ℃ lower than the traditional design.