US 12,258,928 B2
Fuel injector, and method for driving fuel injector
Hisao Ogawa, Kanagawa (JP)
Assigned to MITSUBISHI HEAVY INDUSTRIES ENGINE & TURBOCHARGER, LTD., Sagamihara (JP)
Appl. No. 18/570,843
Filed by MITSUBISHI HEAVY INDUSTRIES ENGINE & TURBOCHARGER, LTD., Sagamihara (JP)
PCT Filed Jun. 22, 2022, PCT No. PCT/JP2022/024918
§ 371(c)(1), (2) Date Dec. 15, 2023,
PCT Pub. No. WO2023/007999, PCT Pub. Date Feb. 2, 2023.
Claims priority of application No. 2021-122450 (JP), filed on Jul. 27, 2021.
Prior Publication US 2024/0295204 A1, Sep. 5, 2024
Int. Cl. F02M 47/02 (2006.01); F02D 41/20 (2006.01)
CPC F02M 47/027 (2013.01) [F02D 41/20 (2013.01); F02D 2041/2017 (2013.01); F02D 2200/0602 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A fuel injector comprising:
a main body part having an inflow port into which fuel that is supplied from a fuel supply source flows, a flow path through which the fuel that has flowed in from the inflow port flows, and a discharge port that is connected to the flow path and discharges the fuel;
a valve unit, at least a part of which is formed using a magnetic body, and which is disposed to be movable in a straight line direction between a position where the discharge port is closed and a position where the discharge port is opened, and is biased in a direction to open the discharge port by pressure of the fuel flowing in from the inflow port, the valve unit being applied with an elastic force in a direction to close the discharge port by an elastic member;
a solenoid device that includes a coil, generates an electromagnetic force by causing a drive current to flow through the coil, and drives the valve unit in the direction to open the discharge port by the electromagnetic force; and
a control unit that variably sets a value of the drive current flowing through the coil in a predetermined period that includes a drive current supply start time point, depending on a supply pressure of the fuel that is supplied to the inflow port,
wherein the control unit makes the value of the drive current in the predetermined period smaller as the supply pressure is higher, and makes the value of the drive current in the predetermined period larger as the supply pressure is lower,
the drive current includes an inrush current that flows through the coil during an inrush period that is a first period that includes a supply start time point in a time series a pull-up current that flows during a pull-up period after the inrush current has flowed, and a hold current that flows during a hold period after the pull-up current has flowed, and
the control unit makes values of the inrush current and the pull-up current smaller as the supply pressure is higher and makes the values of the inrush current and the pull-up current larger as the supply pressure is lower.