Gas fuel injector

Abstract

The invention provides a gas fuel injector which is provided with an electromagnetic valve in a manner of pulling a valve body to a valve seat to close the valve, and can adjust dynamic flow rate. An electromagnetically driven injector for gaseous fuel is provided with: a cylindrical main body in which a fuel passage is formed; an on-off valve for opening and closing the fuel passage; a solenoid for opening the on-off valve; and a nozzle provided at the tip of the main body. The on-off valve includes a valve body that reciprocates together with a plunger constituting the solenoid, and a valve seat that comes into contact with and separates from the valve body, the plunger being fixed to a holder that is provided on the upstream side of the on-off valve, the holder being provided on the upstream side of the on-off valve. The retainer is provided between a closing spring that urges the plunger in a valve closing direction and an adjustment spring that urges the plunger in a valve opening direction.

Description

Technical Field

[0001] The present invention relates to a normally-closed gas fuel injector for directly injecting a flow rate of gas fuel required for an engine driven by a gas fuel such as hydrogen, LPG (Liquefied Petroleum Gas), CNG (Compressed Natural Gas), etc. into a cylinder. Background Art

[0002] Conventionally, an electromagnetic drive type injector that operates an on-off valve by energizing an electromagnetic coil to excite it and injects a flow rate of fuel required for an engine into a cylinder is well-known.

[0003] The electromagnetic on-off valve (solenoid valve) can be classified into a normally-open type and a normally-closed type, and can also be classified into a type that closes the valve by pushing the valve body against the valve seat and a type that closes the valve by pulling the valve body against the valve seat.

[0004] In an injector for in-cylinder direct injection, a solenoid valve of the type that closes the valve by pushing the valve body against the valve seat has an effect of preventing an unexpected valve opening (valve leakage) when the in-cylinder pressure rises. To adjust the dynamic flow rate, generally, the opening and closing delay time of the valve is adjusted by adjusting the set load of a spring that generates a load in the closing direction.

[0005] However, in an injector having a solenoid valve of the type that closes the valve by pulling the valve body against the valve seat, such as the fuel injection device 1A described in Japanese Patent Application Laid-Open No. 2009-526157 (Patent Document 1) (refer to Figure 2 ), since it is structurally difficult to adjust the set load of the spring 4A, it is difficult to adjust the dynamic flow rate.

[0006] Therefore, there is a demand for being able to adjust the dynamic flow rate even in an injector having a solenoid valve of the type that closes the valve by pulling the valve body against the valve seat.

[0007] Prior Art Documents Patent Documents Patent Document 1: Japanese Patent Application Laid-Open No. 2009-526157 Summary of the Invention Problems to be Solved by the Invention The problem of the present invention is to be able to adjust the dynamic flow rate in an injector having a solenoid valve of the type that closes the valve by pulling the valve body against the valve seat.

[0008] Means for Solving the Problems The present invention, which has been completed to solve the above problems, is an injector for gaseous fuel, an electromagnetic-driven injector that directly injects gaseous fuel into the cylinder of an engine, and is characterized by having: a cylindrical main body in which a fuel passage is formed; an on-off valve disposed in the main body to open and close the fuel passage; a solenoid disposed in the main body to open the on-off valve when energized; and a nozzle provided at the front end of the main body on the downstream side of the on-off valve, and injection holes formed at the front end of the nozzle are inserted into the cylinder; the on-off valve includes a valve body and a valve seat, the valve body is fixed to a plunger constituting the solenoid and reciprocates in the axial direction together with the plunger, the valve seat closes the fuel passage by coming into contact with and separating from the valve body, the plunger is fixed to a retainer, the retainer is provided at the proximal end side of the main body on the upstream side of the on-off valve, and the retainer is provided between a closing spring that biases the plunger in the valve-closing direction and an adjustment spring that biases the plunger in the valve-opening direction.

[0009] Thus, by fixing the retainer to the valve body and combining a closing spring that biases the retainer in the valve-closing direction and an adjustment spring that biases the retainer in the valve-opening direction, the dynamic flow rate can be adjusted according to the set loads of both springs.

[0010] In the present invention, the set load of the adjustment spring is set by a piston installed from the proximal end side of the main body, and in this case, the assembly of the adjustment spring can be easily performed.

[0011] In the present invention, the piston can change its position in the axial direction, and the set load of the adjustment spring can be adjusted by the position of the piston. In this case, for example, one type of adjustment spring can be used to set multiple set loads to absorb deviations during manufacturing.

[0012] Effects of the Invention According to the present invention, in an injector of an electromagnetic valve having a method of pulling the valve body toward the valve seat to close the valve, the dynamic flow rate can be easily adjusted. Description of the Drawings

[0013] Figure 1 It is a longitudinal sectional view showing the main part in a preferred embodiment of the gaseous fuel injector of the present invention.

[0014] Figure 2 It is a longitudinal sectional view showing a conventional fuel injection device.

[0015] Description of the Reference Numerals 1 Gas fuel injector, 10 Main body, 11 Fuel passage, 12 Inlet body, 13 Outlet body, 20 On / Off valve, 21 Valve body, 22 Valve seat, 23 Seat surface, 24 Valve hole, 30 Solenoid, 31 Solenoid coil, 32 Fixed iron core, 33 Plunger, 40 Retainer, 41 Closing spring, 42 Adjustment spring, 43 Stopper, 44 Piston. DETAILED DESCRIPTION

[0016] Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. In this specification, gas fuel refers to fuel supplied to an engine and combusted in a gaseous state, such as hydrogen, LPG, CNG, or LNG (Liquefied Natural Gas).

[0017] Figure 1 This is a longitudinal sectional view showing a main part of a preferred embodiment of the gas fuel injector according to the present invention.

[0018] The gas fuel injector 1 is an electromagnetically driven gas fuel injector, and has an on-off valve 20 and a solenoid 30 inside a cylindrical main body 10 formed with a fuel passage 11. The on-off valve 20 includes a valve body 21 and a valve seat 22, which opens and closes the fuel passage 11. The solenoid 30 opens the on-off valve 20 when energized. The gas fuel injector 1 is used to supply gas fuel that has been decompressed and adjusted to a specified pressure from a fuel injection hole formed on a nozzle not shown in the figure at a flow rate required by the engine.

[0019] During use, the electromagnetic coil 31 of the solenoid 30 is energized and excited, whereby the fixed core 32 attracts the plunger 33 to open the on-off valve 20 and directly inject gaseous fuel from the fuel injection hole into the cylinder of the engine.

[0020] The main body 10 is cylindrical in shape and includes an inlet 12 for introducing gas fuel and an outlet 13 for ejecting gas fuel.

[0021] Furthermore, a retainer 40 capable of reciprocating in the axial direction is provided inside the inlet body 12 , and a closing spring 41 urging in the valve closing direction and an adjustment spring 42 urging in the valve opening direction are arranged across the retainer 40 , which is a feature of the present invention.

[0022] One end of the closing spring 41 contacts the retainer 40 , and the other end contacts a stopper 43 formed inside the inlet body 12 .

[0023] One end of the adjustment spring 42 contacts the retainer 40 , and the other end contacts a piston 44 that is positionally variable in the axial direction within the inlet body 12 .

[0024] In addition, in the present embodiment, the closing spring 41 and the adjusting spring 42 are compression coil springs, but other biasing units that exert elastic repulsive force may also be used.

[0025] The on-off valve 20 includes a valve body 21 and a valve seat 22. The valve body 21 is fixed to the plunger 33 and reciprocates in the axial direction together with the plunger 33. The valve seat 22 has a seat surface 23 that contacts and separates from the valve body 21 and a valve hole 24 that penetrates the central portion thereof. The on-off valve 20 pulls the valve body 21 toward the valve seat 22 and brings the valve body 21 into contact with the valve seat 22, thereby closing the valve.

[0026] The solenoid 30 includes an electromagnetic coil 31, a fixed iron core 32 located inside the electromagnetic coil 31, and a plunger 33 (movable iron core) disposed opposite to the fixed iron core 32.

[0027] The fixed iron core 32 is constituted by a cylindrical boss portion that is a part of the outlet body 13 made of a magnetic material.

[0028] The plunger 33 is fixed to the retainer 40. The retainer 40 is disposed inside the inlet body 12 on the upstream side of the on-off valve 20. The retainer is provided between a closing spring 41 that biases the plunger 33 in the valve closing direction ( Figure 1 the upward direction in Figure 1 ), and an adjusting spring 42 that biases the plunger 33 in the valve opening direction (

[0029] the downward direction in Figure 1 ). The acting force of the closing spring 41 is set to be greater than the acting force of the adjusting spring 42. Therefore, when not energized, the on-off valve 20 is closed, that is, a so-called normally closed injector.

[0030] Next, the operation of the solenoid 30 will be described. When current is supplied to the electromagnetic coil 31 (when energized), the fixed iron core 32 generates a magnetic field, the plunger 33 is attracted by the fixed iron core 32, the retainer 40 fixed to the plunger 33 moves in the valve opening direction, the valve body 21 moves in the valve opening direction as the plunger 33 moves, and the valve body 21 separates from the seat surface 23 and the valve opens.

[0031] At this time, by using the closing spring 41 and the adjustment spring 42 disposed with the retainer 40 interposed therebetween, the dynamic flow rate can be adjusted according to the set loads of both springs.

[0032] Furthermore, since the set load of the adjustment spring 42 is set by the piston 44 attached from the base end side of the inlet body 12 in the main body 10 , the adjustment spring 42 can be easily assembled.

[0033] Moreover, in this embodiment, the assembly position of the piston 44 can be changed in the axial direction. Therefore, the set load of the adjustment spring 42 can be adjusted by the position of the piston 44. For example, one adjustment spring can be used to set multiple set loads, and deviations can be absorbed during manufacturing, etc., so that the opening and closing valve 20 can be constructed with high precision and stability.

[0034] The piston 44 can be assembled by any fixing method such as bolting or welding.

[0035] As described above, the present invention can easily adjust the dynamic flow rate of a normally closed gas fuel injector that directly injects gas fuel into a cylinder of an engine by electromagnetic drive.

Claims

1. An injector for gaseous fuel is an electromagnetic-driven injector for directly injecting gaseous fuel into the cylinder of an engine, and is characterized in that comprising: a cylindrical main body having a fuel passage formed therein, an opening / closing valve disposed within the main body for opening and closing the fuel passage, a solenoid disposed within the main body for opening the opening / closing valve upon energization, and a nozzle provided at a front end portion of the main body on the downstream side of the opening / closing valve, and an injection hole formed at a front end of the nozzle is inserted into the cylinder; the opening / closing valve includes a valve body and a valve seat, the valve body being fixed to a plunger constituting the solenoid and reciprocating in the axial direction together with the plunger, and the valve seat opening and closing the fuel passage by contacting and separating from the valve body, the plunger is fixed to a retainer, the retainer being provided at a proximal end side of the main body on the upstream side of the opening / closing valve, the retainer is disposed between a closing spring that biases the plunger in the valve closing direction and an adjustment spring that biases the plunger in the valve opening direction.

2. The gas fuel injector according to claim 1, wherein the adjustment spring has a set load set by a piston mounted from the proximal end side of the main body.

3. The gas fuel injector according to claim 2, wherein [[ID=*]]the assembly position of the piston can be changed in the axial direction, and the set load of the adjustment spring can be adjusted by the position of the piston. It should be noted that there is an error in the original text. In the Chinese text, the item number in is incorrect. It should be instead of [[ID=*]]. The corrected translation is as follows:

3. The gas fuel injector according to claim 2, wherein the assembly position of the piston can be changed in the axial direction, and the set load of the adjustment spring can be adjusted by the position of the piston.

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