JP2516285B2 - Measuring method of oil leakage of fuel injection valve - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil leak amount measuring method for inspecting whether or not the oil leak amount of a fuel injection valve is within a standard value.

[0002]

2. Description of the Related Art For example, as a fuel injection valve of a gasoline engine, a needle type electromagnetic fuel injection valve is generally used in which a needle is lifted by exciting a solenoid to open a nozzle hole at the tip.

FIG. 4 is a sectional view showing the overall construction of the electromagnetic fuel injection valve 1.

In FIG. 1, reference numeral 21 is an injection valve holder having a cylindrical solenoid 22 inside and a fuel inlet 23 provided on a side surface, and 24 is an injection valve holder 21.
A cap attached to the base end of the injection valve holder 21 and a body 26 attached to the tip of the injection valve holder 21; 27 a body 26 and the injection valve holder 2;
The stopper is interposed between the stopper 1 and the stopper 1.

The body 26 has a relatively large opening 28 at the center of the tip, and a conical seating surface 29 is formed on the upstream side of the opening 28.

A needle 30 is provided at the center of the body 26.
Is slidably fitted. The needle 30 is constantly urged downward in the drawing by a coil spring 31 arranged in the injection valve holder 21, and the tip end portion thereof is the seating surface 2 described above.
9 is seated to seal the opening 28, and is lifted upward when the solenoid 22 is excited. The sliding stroke of the needle 30 is regulated to a fixed amount by the stopper 27.

A tubular protector 32 is fitted and fixed to the tip of the body 26, and a plate-shaped plate orifice 33 is sandwiched and fixed between the protector 32 and the tip of the body 26. ing. The plate orifice 33 is arranged along the front end surface of the body 26 so as to close the opening 28 of the body 26, and has a nozzle hole 34 communicating with the opening 28.

Therefore, when the needle 30 is lifted, fuel is injected from the opening 28 through the injection hole 34.

By the way, the needle 3 of the fuel injection valve 1
Although oil leaks from between 0 and the seating surface 29, the amount of leaked oil must satisfy the standard.
Therefore, conventionally, the amount of oil leakage of the fuel injection valve 1 is measured by the following three methods (1) to (3), and an inspection as to whether or not the standard is satisfied is performed.

(1) Visual method After a lapse of a certain time period in which it is possible to determine whether the amount of oil leaking from the fuel injection valve is within a standard value, it is visually determined.

(2) Weight method The oil leakage after a certain period of time is absorbed by a filter paper or the like, and the weight is measured by an electronic balance. Then, subtract the weight of the filter paper only from the measured weight, divide by the specific gravity of the oil,
Calculate the amount of leakage.

(3) Differential pressure detection method Using a differential pressure type leak tester, the differential pressure change between the master side, that is, the fuel injection valve side without oil leakage, and the work side, that is, the measured fuel injection valve side, is used as the oil leakage amount. Replace and ask.

[0013]

However, each of the above-mentioned conventional oil leak measuring methods has the following drawbacks.

(1) Visual method Since the visual measurement person's experience and feelings are used, the judgment result is inaccurate, and it takes a long time before the judgment can be made.

(2) Gravity method Since it is necessary to use a filter paper or an electronic balance, automation is difficult.

(3) Differential pressure detection method Not only is the equipment complicated and expensive, but it also takes a short time due to leakage from the jig, movement of the O-ring, influence of temperature, etc., and mixing of air with oil. Measurement of extremely small amount of oil will be inaccurate.

Therefore, there has been a demand for a method for measuring the amount of oil leakage of a fuel injection valve that is accurate and can be automated.

[0018]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention makes the injection hole portion of the fuel injection valve and the upper end portion of the transparent thin tube contact each other, and the inside of the transparent thin tube is inserted through the fuel injection valve. The measuring oil is filled in and the needle of the fuel injection valve is reciprocated by turning the fuel injection valve on and off to suck the measuring oil in the transparent thin pipe to the first predetermined position in the fuel injection valve. It is judged whether or not the measuring oil has moved from the first predetermined position to the second predetermined position within a predetermined time, and it is judged whether or not the oil leakage amount of the fuel injection valve is within the predetermined amount. The feature is that it is done.

[0019]

Operation: The transparent thin tube is filled with the measuring oil through the fuel injection valve, and then the needle of the fuel injection valve is reciprocated to suck the measuring oil in the transparent thin tube to the fuel injection valve to a predetermined position. Since the amount of oil leakage from the fuel injection valve to the transparent thin tube is measured, the measurement oil in the transparent thin tube can be measured with high accuracy without air being mixed with the measuring oil.

[0020]

1 is a sectional view of an essential part of an apparatus for carrying out an embodiment of a measuring method according to the present invention, and FIG. 2 is a schematic view of the entire hydraulic circuit of the apparatus.

In FIG. 1, reference numeral 2 is a fixing jig for fixing the fuel injection valve 1. The fixing jig 2 has a supply pipe 3a.
A passage 2a for supplying the measuring oil to the fuel inlet 23 of the fuel injection valve 1 and a passage 2b for returning the measuring oil to the return pipe 3b are formed. Although not shown, the connector portion 25 of the fuel injection valve 1 is connected to a power supply circuit and can supply current to the solenoid 22 to turn on / off the injection valve 1. Further, 4 is, for example, a transparent glass thin tube having a diameter of about 0.356 mm, 6a, 7a,
Reference numeral 8a is a light emitting element, and 6b, 7b and 8b are light receiving elements.
The light-emitting element 6a and the light-receiving element 6b, the light-emitting element 7a and the light-receiving element 7b, and the light-emitting element 8a and the light-receiving element 8b are respectively arranged on the detection element supporting portion 5 so as to face each other with the glass thin tube 4 interposed therebetween. It constitutes a pair of photosensors. The distance h between the photosensors 7a and 7b and the photosensors 8a and 8b is set such that the product of the distance h and the inner diameter area of the glass thin tube 4 becomes an allowable limit value of the oil leakage standard. The detection element supporting portion 5 includes the glass thin tube 4, the photosensors 6a, 6b, 7a, 7b, 8
Along with a and 8b, they are moved in the vertical direction in the figure by a moving means (not shown).

In FIG. 2, the bubble removing tank 9 is connected to an oiltight pressure gauge 12 and a fine pressure adjusting pressure gauge 14 via a filter 10 and a damper 11. The oiltight pressure gauge 12 is connected to the supply valve 16 via the oiltight valve 13, and the fine pressure adjusting pressure gauge 14 is connected to the supply valve 16 via the fine pressure valve 15. The supply valve 16 is connected to the fixing jig 2 via the supply pipe 3a, and the fixing jig 2 is connected to the return valve 17 via the return pipe 3b.

Next, a method for measuring the amount of oil leakage will be described.

FIG. 3 is a flow chart of the above measuring method. In step 100 of this flow chart, the detection element supporting portion 5 which is arranged apart from the fixing jig 2 is moved upward, and the upper end portion of the glass thin tube 4 is moved. Is closely attached to the injection valve 1. Next, in step 101, the measuring oil is supplied to the injection valve 1 via the passage 2a. In this case, the oil tight valve 13, the supply valve 16 and the return valve 17 are open. Further, in this case, the injection valve 1 is turned on and the needle 30 is lifted. Therefore, the measuring oil is supplied from the injection holes 34 into the glass capillary 4 by the capillary phenomenon. Next, in step 102, it is determined whether a predetermined time has elapsed. If the predetermined time has not elapsed, the process returns to step 101. The predetermined time is sufficient for filling the glass capillary 4 with the measuring oil. This is because air is discharged from the inside of the thin glass tube 4 before the measurement of the amount of oil leakage, and a measurement error due to the mixing of air into the oil at the time of measurement is avoided. Now, when the predetermined time has elapsed, the routine proceeds to step 103, where the hydraulic pressure is reduced. That is, the oil-tight valve 13 is closed and the fine pressure valve 15 is closed.
Is opened, and the hydraulic pressure on the injection valve 1 side is reduced. Then, it progresses to step 104 and ON / OFF of the injection valve 1 is repeated. This is because the injection valve 1 is repeatedly turned on and off, and the needle 30 is repeatedly moved up and down (reciprocating motion) to perform a pumping operation.
This is because the measuring oil therein is sucked into the injection valve 1 side. Next, in step 105, it is determined whether the photo sensors 7a and 7b are turned on. That is, the glass thin tube 4
The measuring oil inside rises gradually and the photosensors 7a, 7a
It is judged whether or not the level reaches the level of b. If the level of the photo sensors 7a and 7b has not been reached, step 1
Returning to 04, if it has reached, the routine proceeds to step 106, where the injection valve 1 is turned off. Next, in step 107, normal pressure is applied to the injection valve 1. That is, the oil tight valve 13 is opened. Then, in step 108, it is determined whether or not a predetermined time, for example, one minute has elapsed. If the predetermined time has not elapsed, the process proceeds to step 109, where the photo sensor 8a,
It is determined whether 8b is off, that is, whether the amount of leaked oil exceeds the standard value. If the standard value is exceeded, the process proceeds to step 110, and a failure display is given by an appropriate display means (not shown). If the standard value is not exceeded, the process returns to step 107.

Then, in step 108, when a predetermined time has elapsed, the process proceeds to step 111, and the acceptance is displayed by the display means (not shown). Next, in step 112, the supply of the measurement oil is stopped, and in step 113, the detection element support portion 5 is moved downward to separate the glass thin tube 4 from the injection valve 1.

The photosensors 6a and 6b are jig oil leak sensors. If the photosensors 6a and 6b are turned on while the oil leak amount of the injection valve 1 is being measured, the jig 2 and the glass capillary tube are turned on. It is probable that jig oil leakage such as oil leakage from No. 4 occurred. Therefore, this photo sensor 6
When a and 6b are turned on, the measurement is interrupted.

As described above, according to the embodiment of the present invention, the measuring glass thin tube 4 is filled with the measuring oil in advance, and the glass thin tube 4 is pumped by turning on / off the injection valve 1. The measurement oil is raised to a predetermined position, and then it is determined whether or not the amount of oil leaked within a predetermined time is within a standard value by detecting the oil level position of the measurement oil in the glass capillary 4 with a photo sensor. Since this is done, the amount of oil leakage of the injection valve 1 can be measured with high accuracy and automation becomes possible. Furthermore, since the amount of oil leakage can be measured using an inexpensive glass thin tube, the equipment cost can be reduced.

Photosensors 6a, 6b, 7a, 7
The positions of b, 8a, 8b on the detection element supporting portion 5 may be arbitrarily adjusted.

Further, the measuring oil in the glass capillary 4 may be discharged by air blow after every measurement.

[0030]

As described above, according to the present invention, the injection hole portion of the fuel injection valve and the upper end portion of the transparent thin tube are brought into contact with each other, and the measuring oil is injected into the transparent thin tube through the fuel injection valve. When the fuel injection valve is full, the needle of the fuel injection valve is reciprocated to cause the measuring oil in the transparent thin tube to be sucked into the fuel injection valve to the first predetermined position. Since it is determined whether or not the vehicle has moved from the first predetermined position to the second predetermined position within a predetermined time, it is determined whether or not the oil leakage amount of the fuel injection valve is within a predetermined amount. The amount of oil leakage can be measured with high accuracy and the measurement can be automated without air being mixed into the measuring oil in the transparent thin tube at the time of measurement.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of an apparatus for carrying out an embodiment of the present invention.

FIG. 2 is an overall schematic diagram of a hydraulic circuit.

FIG. 3 is a flowchart of an embodiment of the present invention.

FIG. 4 is a sectional view of an electromagnetic fuel injection valve.

[Explanation of symbols]

1 ... Fuel injection valve, 2 ... Fixing jig, 4 ... Transparent thin tube, 30 ...
needle.

Claims (1)

(57) [Claims] 1. An injection hole portion of a fuel injection valve and an upper end portion of a transparent thin tube are brought into contact with each other to fill the measuring oil into the transparent thin tube through the fuel injection valve, and by turning on / off the fuel injection valve. The needle of the fuel injection valve is reciprocated so that the measuring oil in the transparent thin tube is sucked up to the first predetermined position by the fuel injection valve, and the measuring oil in the transparent thin tube is moved from the first predetermined position within a predetermined time. A method for measuring the amount of oil leakage from a fuel injection valve, wherein it is determined whether or not it has moved to a second predetermined position, and whether or not the amount of oil leakage from the fuel injection valve is within a predetermined amount.