Fuel injection device

Abstract

A fuel injection device is provided, wherein a fuel introducing flow path (22) for introducing high-pressure fuel into a control room (12) from a fuel supplying flow path (16), and a check valve for controlling the opening and the closing of a clearance (42) are formed inside an orifice plate (7). Therefore, the time (valve-opening response time) from the opening of a solenoid-controlled valve tothe opening of a needle (4) is shortened. In addition, the time (valve-closing response time) from the closing of the solenoid-controlled valve to the closing of the needle (4) is shortened. The closing of the needle (4) is accelerated, and the valve-closing responsiveness is improved. Additionally, in an injection period that the solenoid-controlled valve is opened, the check valve is closed andthe needle (4) is opened, the check valve closes the fuel introducing flow path (22) with a larger flow path section area, so abnormal injection actions such as the closing of the needle (4) can be prevented during the fuel injection into a combustion chamber of a cylinder of an engine.

Description

technical field [0001] The present invention relates to a fuel injection device for injecting fuel into a combustion chamber of an internal combustion engine, and in particular to a fuel injection device that uses at least two first and second control valves to control the fuel pressure in the control chamber, thereby improving the stability of the needle. A fuel injection device (injector) with valve opening responsiveness and needle closing responsiveness. Background technique [0002] In the past, such as Figure 10 with Figure 11 As shown, a known fuel injection device (injector of prior art 1) has the following components (for example, refer to Japanese Patent Application Laid-Open No. 09-032681): a needle 102 for switching to and from the combustion chamber of an internal combustion engine (engine) The nozzle hole 101 for injecting fuel; the nozzle chamber 103, the fuel pressure inside the nozzle chamber 102 applies the oil pressure (valve opening force: F1) to the n...

AI Technical Summary

Problems solved by technology

[0011] However, in the case of the injector of prior art 2, when the valve 121 of the electromagnetic control valve is opened, the fuel in the control chamber 104 will flow out from the outlet orifice 119, causing the fuel pressure in the control chamber 104 to drop, And a lot of high-pressure fuel will be discharged from the inlet orifice 118 to the low-pressure side due to the suction effect generated by the fuel flow rate flowing through the fuel discharge flow path 116, the so-called spray effect (or injector effect).

[0012] In addition, the injection water hammer (pressure fluctuation) caused by the valve opening of the needle 102 is applied to the intermediate valve 108 from the fuel supply channels 111 to 113 and the fuel introduction channels 114 and 115, causing the intermediate valve 108 to open.

The opening of the intermediate valve 108 may cause high-pressure fuel to flow into the control chamber 104 during the fuel injection, causing the needle 102 to close the valve and causing fuel injection to be interrupted.

[0013] Moreover, since the middle valve 108 is in the shape of a flat plate, the contact with the seat surface of the orifice plate 106 (seating) is realized in a plane, therefore, when the needle 102 opens the valve, it is easy for the high-pressure fuel to flow from the fuel introduction flow path 115 to the control chamber. Leaks in 104 that could affect stable fuel injection

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