JP2007321668A - Method for pumping fuel into fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for pouring fuel into a fuel injection valve capable of surely pouring working oil into the fuel injection valve and removing air in the fuel injection valve in a short period of time and not necessary to wipe a fuel injection valve surface after pouring working oil. <P>SOLUTION: This method for pouring fuel includes a vacuuming step opening a first connection port and closing a second connection port and sucking air or fuel in the fuel injection valve by a vacuum pump, and a fuel pouring step opening the second connection port and closing the first connection port and pouring pressurized fuel in the fuel tank into the fuel injection valve. The fuel pouring step is executed after the vacuuming step. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for injecting fuel into a fuel injection valve.

  Conventionally, as shown in FIG. 3, the primary piston 96 and the secondary piston 94 are slidable in the housing 91 in the longitudinal direction of the fuel injection valve in the piston receiving holes 95 and 93 extending in the longitudinal direction of the fuel injection valve. A hydraulic chamber 97 (also referred to as a displacement expansion chamber) is defined by the bottom surface of the primary piston 96, the top surface of the secondary piston 94, and the inner wall surfaces of the piston receiving holes 95 and 93, and the hydraulic chamber 97 is made into hydraulic fluid. For example, when the actuator 99 is extended, for example, to fill with fuel and start fuel injection, and the primary piston is displaced toward the hydraulic chamber, the volume of the hydraulic chamber decreases and the pressure in the hydraulic chamber increases, thereby increasing the secondary pressure. The piston is displaced in the direction away from the hydraulic chamber, and the actuator is contracted, for example, to stop fuel injection, and the primary piston is changed in the direction away from the hydraulic chamber. Then, a fuel injection valve is known in which the volume of the hydraulic chamber increases and the pressure in the hydraulic chamber decreases, thereby causing the secondary piston to displace toward the hydraulic chamber (for example, Patent Document 1 or 2). .

  In such a fuel injection valve, the primary piston and the secondary piston are inserted oil-tightly into the piston accommodating holes, respectively, so that the hydraulic oil is not leaked from the hydraulic chamber as much as possible. In other words, it is not easy for fluid to enter the hydraulic chamber from the outside.

  Then, when the primary piston is displaced toward the hydraulic chamber, the hydraulic oil in the hydraulic chamber acts as an incompressible fluid, so that the displacement of the primary piston is quickly transmitted to the secondary piston. However, if air bubbles, such as air or hydraulic oil vapor, are present in the hydraulic chamber, these bubbles act as a compressive fluid, so even if the primary piston is displaced, the secondary piston cannot be displaced quickly, and as a result There is a possibility that the fuel injection timing may deviate from the normal time due to a delay. Further, when the bubbles are injected together with the fuel, the amount of the fuel actually injected becomes smaller than the regular fuel. That is, the fuel injection timing or the fuel injection amount may deviate from the normal timing or amount.

  By the way, immediately after the fuel injection valve is assembled, the fuel injection valve is not filled with fuel, and naturally, only air exists in the hydraulic chamber. In this state, when the fuel supply device is connected to the fuel injection valve and fuel injection is to be executed, the primary piston is displaced because the hydraulic oil is not infiltrated and air exists in the hydraulic chamber. However, the secondary piston does not displace following the displacement, and the injection amount and the injection timing are greatly different from the normal required values.

  For the above reasons, it is necessary to completely fill the hydraulic chamber with fuel as hydraulic oil before fuel injection is executed. Conventionally, fuel is injected into the fuel injection valve by the following method.

  FIG. 5 is a diagram showing a conventional method for injecting fuel into a fuel injection valve (see, for example, Patent Document 3). As shown in FIG. 5, the vacuum chamber 31 has a size that allows the entire container 30a to be placed therein, and has a structure that can be sealed. A vacuum pump 32 is connected to the vacuum chamber 31. By operating the vacuum pump 32, the atmospheric pressure in the vacuum chamber 31 can be made lower than the external atmospheric pressure (atmospheric pressure). .

  The container 30 a in which the fuel F is stored and the fuel injection valve 90 is installed is installed in the vacuum chamber 31. And after sealing the vacuum chamber 31, the vacuum pump 32 is operated and the atmospheric pressure in the vacuum chamber 31 is reduced. At this time, the air in the vacuum chamber 31 is discharged to the outside and the hydraulic pressure of the fuel that is the working oil is also reduced, so that the air present in the fuel injection valve 90 is easily discharged. That is, the air in the hydraulic chamber 97 is also easily discharged to the outside. As a result, the hydraulic oil is injected into the hydraulic chamber 97 in exchange for such air discharge, and eventually the hydraulic chamber 97 is filled with the hydraulic oil.

  Thereafter, the vacuum pump 32 is stopped so that the pressure inside the vacuum chamber 31 is the same as the pressure outside the vacuum chamber 31. Next, the container 30 a is removed from the vacuum chamber 31 while maintaining the state where the entire fuel injection valve 90 is immersed in the hydraulic oil. Thereafter, the fuel injection valve 90 is taken out from the container 30a. Since the working oil adheres to the surface of the fuel injection valve immediately after this removal, it is necessary to wipe this working oil manually using a waste cloth.

  In this conventional method, as described above, since it takes a long time to allow fluid to enter the hydraulic chamber of the fuel injection valve from the outside, it takes a long time of about 40 minutes to fill the hydraulic chamber with fuel. . In addition, it was a cumbersome task to wipe off the hydraulic oil adhering to the surface of the fuel injection valve by hand. For these reasons, the process of injecting hydraulic oil into the fuel injection valve has become inefficient, which has seriously hindered the production efficiency of the fuel injection valve.

JP 2005-54599 A JP 2005-76571 A JP 2003-269285 A

  The present invention has been made in view of the above problems, and an object of the present invention is to inject fuel oil into a fuel injector and inject fuel into a fuel injector, particularly a fuel injector having a hydraulic chamber filled with hydraulic fluid. To provide a method for injecting fuel into a fuel injection valve, which can remove bubbles (air) in the valve reliably and in a short time and does not need to wipe the surface of the fuel injection valve after injection of hydraulic oil. is there.

The present invention provides a fuel injection method according to each of the claims as means for solving the above-mentioned problems.
According to the first aspect of the present invention, the fuel injection method is such that the first connection port is opened and the second connection port is closed simultaneously, and the air or fuel in the fuel injection valve is sucked and discharged by the vacuum pump. And a fuel injection step of injecting the pressurized fuel in the fuel tank into the fuel injection valve by opening the second connection port and simultaneously closing the first connection port, and injecting the fuel after the evacuation step The step is executed.

  By making the evacuation step and the fuel injection step independent from each other and executing the fuel injection step after executing the evacuation step, the injection of hydraulic oil into the hydraulic chamber of the fuel injection valve and the bubbles in the chamber are performed. (Air) can be removed reliably and in a short time, and it is possible to eliminate the need to wipe the surface of the fuel injection valve after the hydraulic oil is injected.

  According to the second aspect of the present invention, the fuel injection method is characterized in that the evacuation step and the fuel injection step are alternately performed. By executing these steps alternately a plurality of times, it is possible to more reliably remove bubbles (air) in the hydraulic chamber of the fuel injection valve.

  According to the third aspect of the present invention, the fuel injection system includes a switching valve having a function of switching between the first connection port and the second connection port. By adopting this switching valve, the fuel injection system can be made simple and compact.

  According to a fourth aspect of the present invention, the fuel injection method is characterized in that the fuel injection step is started after the negative pressure in the fuel injection valve becomes a predetermined value or less in the evacuation step.

  According to the fifth aspect of the present invention, the fuel injection method also executes the fuel injection amount measurement step in parallel with the fuel injection step, and when a predetermined time has elapsed from the start of fuel injection in the fuel injection step. When the fuel injection amount is less than a predetermined value, the evacuation step is started.

  According to the invention described in claim 6, the fuel injection valve is provided with a hydraulic chamber filled with hydraulic oil. If the method according to the present invention is used as a method for injecting fuel into a fuel injection valve provided with a hydraulic chamber, the effect is remarkable.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a view for explaining a vacuuming step according to the first embodiment of the present invention. FIG. 2 is a view for explaining the fuel injection step of the first embodiment according to the present invention. FIG. 3 is a cross-sectional view of the fuel injection valve. FIG. 4 is a view for explaining a fuel injection method according to the present invention.

(First embodiment)
In FIG. 1, 90 is a fuel injection valve, 90a is a fuel injection port of the fuel injection valve 90, 1 is a switching valve, 1a is a first connection port of the switching valve 1, 1b is a second connection port of the switching valve 1, 1c is a third connection port of the switching valve 1, and 1d is a connection port switching butterfly valve. 2 is a fuel tank, 3 is a pressure pump, 4 is a vacuum pump, 5 is a vacuum gauge, and 6 is a fuel flow meter. 5 is a vacuum gauge for measuring a negative pressure in a first connection pipe 11 described later, 6 is a flow meter for measuring a fuel flow rate in a second connection pipe 12 described later, and 7 is a controller. 11 is a first connection pipe that connects the first connection port 1a of the switching valve 1 and the vacuum pump 4, and 12 is a second connection pipe that connects the second connection port 1b of the switching valve 1 and the fuel tank. , 13 is a third connection pipe that connects the fuel injection port 90a and the third connection port 1c of the switching valve 1. F is a fuel stored in the fuel tank 2 and pressurized by the pressurizing pump 3 through an air reservoir.

  The switching valve 1 is a two-way solenoid valve (two-way solenoid valve), and the third connection port 1c connected to the fuel injection port 90a of the fuel injection valve 90 is always open. It has a function of switching the opening and closing of the connection port 1a and the second connection port 1c. In the second or third embodiment described later, the controller 7 receives signals from the vacuum gauge 5 or the flow meter 6, internally processes those signals in an internal circuit, and sends a control signal to the switching valve 1. Send.

  FIG. 1 represents the evacuation step of the present invention. That is, the first connection port 1a connected to the vacuum pump 4 is opened, and the second connection port 1b connected to the fuel tank 2 is closed. The vacuum pump 4 sucks air or fuel in the fuel injection valve 90 (including air or fuel in the hydraulic chamber 97) through the third connection pipe 13, the switching valve 1 and the first connection pipe 11 to the fuel tank. Discharge. This is a so-called vacuuming operation. By this evacuation operation, the inside of the fuel injection valve 90 (including the hydraulic chamber 17) is in a state close to vacuum.

  FIG. 2 represents the fuel injection step of the present invention. That is, the first connection port 1 a connected to the vacuum pump 4 is closed, and the second connection port 1 b connected to the fuel tank 2 is opened. The fuel F is stored in the fuel tank 2 and is pressurized by the pressurizing pump 3 through the air L at, for example, 0.1 MPa. The fuel F pressurized by the pressurizing pump 3 through the air L is contained in the fuel injection valve 90 (including hydraulic pressure) via the second connection pipe 12, the switching valve 1, the third connection pipe 13, and the fuel injection port 90a. Injected into the chamber 17).

  Next, a method for injecting fuel into the fuel injection valve 90 will be described. 4A and 4B are diagrams for explaining the fuel injection method according to the present invention. FIG. 4A is a diagram showing the change in the hydraulic chamber fuel amount k with respect to time t, and FIG. 4B is the hydraulic chamber air amount j. It is a figure showing the change with respect to time t. As shown in FIG. 4, the first evacuation step is started at time t1. The state of the switching valve 1 at this time is such that the first connection port as shown in FIG. 1 is opened and the second connection port is closed. At this time, the hydraulic indoor air is sucked by the vacuum pump 4, passes through the discharge pipe 14, and is discharged to the upper air reservoir of the fuel tank 2. At first, the hydraulic indoor air amount j rapidly decreases, and then gradually decreases after a certain point.

  At time t2 after 15 seconds, the butterfly valve of the switching valve 1 is rotated, the first connection port is closed, and the second connection port is opened. Thereby, the first evacuation step is completed, and the first fuel injection step is started. At this time, air is not completely removed in the hydraulic chamber, and there is a residual air amount indicated by Δ.

  For this reason, even if the first fuel injection step is executed for a long time, it is difficult to achieve the target fuel filling into the hydraulic chamber. When the pressurized fuel F starts to flow into the hydraulic chamber 17 at time t2, the residual air is compressed by the pressurized fuel F. At time t3 after about 3 seconds, the fuel injection step is completed, and the second evacuation step is started. Then, the fuel filled in the hydraulic chamber is rapidly decompressed, and the compressed residual air rapidly expands and melts into the fuel as fine bubbles. At time t4, the residual air that has dissolved into the fuel in the form of fine bubbles is sucked by the vacuum pump 4 together with the fuel filled in the hydraulic chamber, passes through the discharge pipe 14, and accumulates in the upper air of the fuel tank 2. Is discharged.

  As a result, the hydraulic indoor air amount becomes substantially zero at time t4. Then, at time t5, 15 seconds after time t3, the second evacuation step is completed, and the second fuel injection step is started. Since the residual air amount in the hydraulic chamber is almost zero, the fuel charge amount k in the hydraulic chamber reaches the target value Z (that is, the hydraulic chamber volume) at time t6, which is 3 seconds after time t5. Thereafter, the coupler (not shown) forming the fuel injection port 90 a is loosened, and the fuel injection valve 90 is removed from the third connection pipe 13. Since the fuel injection valve 90 injects fuel using the fuel injection port 90a, the fuel does not adhere to the surface.

  In this way, a total 18-second cycle in which the evacuation step is executed for 15 seconds and the fuel injection step is executed for 3 seconds is continuously executed twice. Thereby, the amount of residual air in the hydraulic chamber becomes almost zero. That is, since the fuel injection process can be completed with a fuel injection time of 36 seconds for one fuel injection valve, the process time can be greatly reduced as compared with the conventional 40 minutes.

(Second Embodiment)
In the first embodiment, after the evacuation step is executed for 15 seconds, the fuel injection step is started. Although the setting for 15 seconds is based on an experiment, the evacuation step execution time differs depending on the type of the fuel injection valve.

  As a countermeasure, the negative pressure at that position is detected by a vacuum gauge 5 installed between the vacuum pump 4 and the first connection port 1a of the switching valve 1, and the negative pressure is reduced to a predetermined value or less in the vacuuming step. After that, the controller 7 may issue a command to the switching valve 1 to start the fuel injection step. By detecting this negative pressure, it can be substantially confirmed that the amount of air j in the hydraulic chamber has become, for example, Δ or less, and the same effect as in the first embodiment can be obtained. Thereby, it becomes possible to respond to the fuel injection process of many types of fuel injection valves.

(Third embodiment)
The fuel injection step further includes a fuel injection amount measurement step for measuring the fuel injection amount to the fuel injection valve in the fuel injection step. At the time of executing the fuel injection step, the fuel injection amount measurement step is also executed in parallel. If the fuel injection amount is less than a predetermined value (for example, the target fuel filling amount Z in the hydraulic chamber) when a predetermined time has elapsed from the time, the evacuation step may be started.

  Only in the first cycle, the residual air amount in the hydraulic chamber becomes almost zero, and the fuel amount in the hydraulic chamber reaches the target filling amount Z in most cases, so the third embodiment is effective. As a result of experiments using ten fuel injection valves, there were nine fuel injection valves in which the amount of fuel in the hydraulic chamber reached the target filling amount Z only in the first cycle. In this case, it is not necessary to execute the second cycle.

  More specifically, as shown in FIG. 1, a fuel flow meter 6 is installed in the second connection pipe 12, and in the fuel injection step, the fuel flow rate is measured when a predetermined time (for example, 15 seconds) elapses from the start of fuel injection. . This fuel flow rate becomes the amount of fuel injected into the hydraulic chamber 17 of the fuel injection valve. When the fuel flow rate is less than the target fuel filling amount Z, the controller 7 issues a command to the switching valve 1, ends the fuel injection step, and starts the evacuation step. When the fuel flow rate is equal to or higher than the target fuel filling amount Z, the fuel injection process of the fuel injection valve is completed. Thereby, when fuel is injected into a large number of fuel injection valves, the total time required for the process can be greatly reduced.

  By the method described above, injection of hydraulic oil into the fuel injection valve and removal of bubbles (air) in the fuel injection valve can be performed reliably and in a short time, and the surface of the fuel injection valve after injection of hydraulic oil is wiped off. Is no longer necessary.

It is a figure for demonstrating the evacuation step of 1st Embodiment which concerns on this invention. It is a figure for demonstrating the fuel injection | pouring step of 1st Embodiment which concerns on this invention. It is sectional drawing of a fuel injection valve. It is a figure for demonstrating the fuel injection method which concerns on this invention. It is a figure for demonstrating the fuel injection method to the conventional fuel injection valve.

Explanation of symbols

90 Fuel Injection Valve 1 Switching Valve 2 Fuel Tank 3 Pressure Pump 4 Vacuum Pump

Claims (6)

A fuel injection valve (90);
A vacuum pump (4) connected to the fuel injection valve via a first connection port (1a);
Fuel injection to a fuel injection valve comprising a fuel tank (2) connected to the fuel injection valve via a second connection port (1b) and receiving fuel (F) stored therein. In the system,
Evacuation step of opening the first connection port and closing the second connection port, and sucking and discharging air or fuel in the fuel injection valve by the vacuum pump;
A fuel injection step of opening the second connection port and closing the first connection port and injecting pressurized fuel in the fuel tank into the fuel injection valve;
A fuel injection method for a fuel injection valve, wherein the fuel injection step is executed after the evacuation step.   The fuel injection method according to claim 1, wherein the evacuation step and the fuel injection step are alternately performed.   The first connection port has a third connection port (1c) connected to the fuel injection port (90a) of the fuel injection valve (90), the first connection port (1a), and the second connection port (1b). The fuel injection method according to claim 1 or 2, wherein the fuel injection system includes a switching valve (1) having a function of switching between the first connection port and the second connection port. Detecting the negative pressure upstream of the vacuum pump;
4. The fuel injection method according to claim 1, wherein the fuel injection step is started after the negative pressure becomes equal to or lower than a predetermined value in the vacuuming step. 5. A fuel injection amount measuring step of measuring a fuel injection amount into the fuel injection valve in the fuel injection step;
During the fuel injection step, a fuel injection amount measurement step is also executed in parallel.
5. The evacuation step is started when the fuel injection amount is less than a predetermined value when a predetermined time has elapsed from the start of fuel injection in the fuel injection step. 6. The fuel injection method described in 1.   The fuel injection method according to any one of claims 1 to 5, wherein the fuel injection valve (90) includes a hydraulic chamber (97) filled with hydraulic oil.

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