JPH07119585A - Fuel injection valve inspecting device - Google Patents

Abstract

PURPOSE:To increase a measurement precision for a fuel leakage amount so as to improve reliability in good/defect determination by detecting a condition change in fuel, which leaks to a leakage fuel sump chamber communicated with an injection part of a fuel injection valve. CONSTITUTION:A fuel injection valve 1 is positioned in a set platform 20, and a pressure in a valve chest 16 is increased when fuel is fed to a fuel supply port, 13 from a fuel supplying unit 19 at a pressure close to an actual using condition. During the increase of the pressure, fuel in the valve chest 16 leaks from between a valve seat 8 and a valve unit 12, and the leakage fuel flows from a sack hole 7 into a leakage fuel sump chamber 22 via an injection hole 6. When a pressure of the sump chamber 22 is increased, a float 23 is shifted, and a detection object unit 23a of the float 23 is brought close to a reference object unit 25a of a displacement sensor 25. Subsequently, the displacement sensor 25 outputs a float displacement distance DELTAX and its displacement time DELTAT to a data processing unit 26, so that a fuel leakage amount Q per unit time is detected. In addition, the data processing unit 26 compares the reference leakage amount and the measured leakage amount with each other so as to determine whether it is a good item or not, and information that it is a good/defective item is indicated in a display unit 27.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for inspecting a fuel injection valve used in an internal combustion engine.

[0002]

2. Description of the Related Art An internal combustion leak of a fuel injection valve is one of important valve characteristics because it adversely affects fuel economy and fuel injection metering. Therefore, the fuel leak is inspected before mounting the fuel injection valve on the engine.

A conventional fuel leak inspection device for a fuel injection valve is disclosed in, for example, Japanese Patent Laid-Open No. 4-370365. In this device, air is supplied to the master fuel injection valve and the sample fuel injection valve instead of fuel, the air leak amounts of these are measured, and both air leak amounts are compared with each other to determine the quality of the sample fuel injection valve. Making a decision.

[0004]

However, since the quality of the actual fuel leakage is estimated by comparing the air leak amounts, the conditions when the fuel injection valve is actually used and the conditions at the time of inspection are different. As a result, there are problems that the accuracy of the fuel leakage amount is deteriorated and the reliability of the pass / fail judgment is lacking.

An object of the present invention is to make these conditions as close as possible to reduce the cause of error and improve the measurement accuracy of the fuel leakage amount to improve the reliability of the quality judgment.

Since the fuel injection valve described in the above publication is opened / closed by an electromagnetic actuator, the valve closed state can be arbitrarily maintained, but the fuel injection valve used in a diesel engine or the like is opened / closed by the fuel pressure and thus closed. It is difficult to maintain the valve state. Therefore, depending on the type of valve, the measuring means using air cannot be applied as it is, and it has been desired to devise a more versatile measuring means.

[0007]

In a fuel injection valve inspection apparatus according to the present invention, when a fuel injection valve for injecting fuel at a fuel pressure to be inspected is set, a leakage fuel reservoir chamber communicating with an injection hole thereof, The fuel injection valve includes means for supplying fuel and means for detecting a change in the state of the fuel leaking into the storage chamber. In particular, the present inspection device is characterized in that the fuel to be actually used is supplied to the fuel injection valve at a pressure close to the state of use.

[0008]

When the fuel is supplied to the fuel injection valve, the fuel inside the valve leaks from the injection hole to the reservoir chamber as the pressure increases. Then, the state change of the fuel in the storage chamber is detected.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a fuel injection valve inspection apparatus according to a first embodiment of the present invention will be described with reference to FIG.

First, an example of the fuel injection valve 1 to be inspected will be outlined. This fuel injection valve 1 is generally called a seat valve, and a body nozzle 3 is fitted in a nozzle holder 2 and a needle 4 is inserted into this body nozzle 3. An injection port portion 5 is projectingly provided at the tip of the body nozzle 3, and an injection hole 6 in the injection port portion 5 communicates with a valve seat 8 via a suck hole 7. The needle 4 is supported movably with respect to the body nozzle 3 by the guide portion 9 on the proximal end side thereof, and the valve opening pressure adjusting spring 11 is interposed between the valve opening pressure adjusting bolt 10 and the guide portion 9 in the nozzle holder 2. ing. The valve opening pressure adjusting spring 11 biases the needle 4 toward the valve seat 8, and the valve portion 12 on the tip end side of the needle 4 is pressed against the valve seat 8. The nozzle holder 2 has a fuel supply port 13
And the supply port 13 is provided with a passage 14 of the nozzle holder 2.
Further, the valve seat 8 communicates with a passage 15 of the body nozzle 3 and a valve chamber 16 in the body nozzle 3.

Next, a device 17 for inspecting such a fuel injection valve 1 will be described. The inspection device 17 is roughly divided into a fuel leak amount detection unit 18 and a fuel supply unit 19. In the fuel leak amount detection unit 18, a leak fuel reservoir chamber 22 is formed in the center of a positioning recess 21 on the lower side of the set table 20, and a float 23 is movably inserted into the reservoir chamber 22. . The displacement sensor 25 is attached to the cover 24 on the set table 20, and the float 23 protruding from the set table 20 is close to the displacement sensor 25 in the cover 24.

The displacement sensor 25 measures a change in the distance between the reference object portion 25a and the detection object portion 23a of the float 23. The displacement distance ΔX of the float 23 with respect to the reference set distance Xo and the float 23. Of the displacement time ΔT from the start to the end of the movement of the
It is designed to output to 6. Then, the data processing unit 26 uses the input signal from the displacement sensor 25 to calculate the average fuel leakage amount Q per unit time by the following relational expression.
Is calculated.

[0013]

[Equation 1]

Further, the data processing unit 26 compares the standard set fuel leakage amount Qo stored in advance with the measured fuel leakage amount Q to judge pass / fail, and displays the good product or the defective product on the display unit 27. It has become.

The fuel injection valve 1 is connected to the fuel leak amount inspection unit 18
When positioning on the setting table 20, first, the body nozzle 3 is inserted into the retaining nut 28 and the nozzle holder 2 is screwed, and then the body nozzle 3 is inserted into the positioning recess 21 of the setting table 20. The retaining nut 28 is screwed. In this state, the injection port 5 leaks and the fuel storage chamber 22
The leak fuel storage chamber 22 is sealed by the float 23 and the body nozzle 3.

On the other hand, in the fuel supply unit 19, the fuel supply pump 30 connected to the fuel tank 29 includes a relief valve 31, a pressure reducing valve 32, an accumulator 33 and a pressure gauge 3.
4 and a flow meter 35, the fuel injector 1 is connected to the fuel supply port 13.

Next, the case of inspecting the fuel injection valve 1 by using such an inspection device 17 will be described. First, in a state where the fuel injection valve 1 is separated from the set table 20 of the fuel leak amount inspection unit 18, the set pressures of the relief valve 31 and the pressure reducing valve 32 are adjusted according to the actual working pressure of the fuel, and the pressure gauge 34 While watching, the valve opening pressure adjusting bolt 10 is operated so as to inject at a predetermined valve opening pressure. By the way, before the valve is opened, the pressure of the pressure gauge 34 or a pressure sensor which substitutes for it is proportional to the flow rate of the flow meter 35, but when the valve is opened, the flow rate suddenly increases. You can know the valve pressure. The valve opening pressure can be adjusted arbitrarily. Therefore, the pressure reducing valve 32 is set to a pressure slightly lower than the predetermined valve opening pressure, and the following inspection is performed.

Next, the fuel injection valve 1 is positioned on the set table 20 as described above. When the fuel is sent from the fuel supply unit 19 to the fuel supply port 13 at a pressure close to the actual use state, the fuel is supplied to the valve chamber 16 of the fuel injection valve 1 through the passages 14 and 15, and the pressure in the valve chamber 16 increases. To do. During the increase, the fuel in the valve chamber 16 leaks from between the valve seat 8 and the valve portion 12, and the leaked fuel flows from the suck hole 7 through the injection hole 6 into the leak fuel storage chamber 22.

When the pressure in the leak fuel storage chamber 22 rises,
The float 23 moves and the detection target portion 23a approaches the reference target portion 25a of the displacement sensor 25. Then, the displacement sensor 25 outputs the float displacement distance ΔX and the float displacement time ΔT to the data processing unit 26. Data processing unit 2
Reference numeral 6 detects the fuel leakage amount Q per unit time based on these input signals. Further, the data processing unit 26 compares the standard set fuel leakage amount Qo with the measured fuel leakage amount Q to determine whether the quality is good or bad, and displays a good product or a defective product on the display unit 27.

Since the fuel leak amount Q is very small, a measurement error is likely to occur due to the influence of the thermal expansion of the fuel leak amount detecting section 18. Therefore, it is preferable to measure in a thermostatic chamber.
In the above-described embodiment, the stability is maintained by the weight of the float 23 and the movement resistance force, but in the second embodiment shown in FIG. 2, the float 23 is biased toward the injection port portion 5 side by the vibration-proof spring 36. Therefore, the stability of the float 23 is further assured to improve the measurement accuracy.

The most characteristic point of both the embodiments is that the fuel leakage amount Q is measured in the state where the actual fuel is used and the state is close to the actual use state. Differently, the measurement accuracy can be improved.

Further, since the flow rate of the fuel leaking from the fuel injection valve 1 to the reservoir chamber 22 (the volume change amount of the fluid moving in a unit time) is directly measured, the accuracy of the actual fuel leakage amount can be improved. it can.

As described above, the fuel supply unit 19 is provided with the flow meter 35. With this flow meter 35, the amount of fuel leakage in the guide portion 9 of the needle 4 can be measured. In the above-described embodiment, the flow rate of the fuel leaking from the reservoir chamber 22 is measured by the displacement sensor 25, but as another measuring means, for example, a pressure change in the reservoir chamber having a constant volume is detected and detected. The value may be converted into a flow rate.

[0024]

According to the fuel injection valve inspection apparatus of the present invention, the fuel leakage amount can be measured in the actual fuel usage state, so that the measurement accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a schematic system diagram showing a fuel injection valve inspection device according to a first embodiment of the present invention.

FIG. 2 is a schematic system diagram showing a fuel injection valve inspection device according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel injection valve, 6 ... Injection hole, 17 ... Fuel injection valve inspection device, 18 ... Fuel leak amount detection part, 19 ... Fuel supply part, 22
... Leakage fuel storage chamber, 23 ... Float, 25 ... Displacement sensor.

Claims (1)

[Claims] 1. A leakage fuel storage chamber communicating with an injection hole when a fuel injection valve for injecting fuel at a fuel pressure to be inspected is set, and fuel used for this fuel injection valve at a pressure close to its used state. A fuel injection valve inspection apparatus comprising: a supply unit; and a unit that detects a change in the state of the fuel leaking into the storage chamber.