JPH09257631A - Leak tester having temperature-error compensating function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compensate for the measuring error caused by the temperature change of a body under inspection and to improve the accuracy of a leak test with regard to a leak tester having a temperature-error compensating function for inspecting the airtightness of the body uner indpection such as the fuel supply device in an inter nal combustion engine. SOLUTION: In a leak tester, which inspects the sealing property of a body under inspection 1 by applying fluid pressure on the body under inspection 1 having a heat source, a master 2 having the specified internal volume and heat capacity, a pressure source 3, which supplies fluid having the approximately same pressure to the body under inspection 1 and the master 2, and measuring devices 4 and 5, which measure the pressure difference between the pressure of the fluid supplies to the body under inspection 1 from the pressure source 3 and the pressure of the fluid supplied to the master 2, and provided. A heating device 30, which heats the master 2 to the specified temperature, is provided so as to detects the presence or absence of the leak to the outside of the body under inspection 1 based on the measured results of the measuring device 4 and 5 and to compensate for the measuring error caused by the temperature change of the body under inspection 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak tester for inspecting the airtightness of an object to be inspected such as a fuel supply device in an internal combustion engine, and more particularly to a leak error tester having a temperature error compensating function suitable for an object to be inspected having a heat source Regarding leak tester.

[0002]

2. Description of the Related Art Conventionally, in a fuel supply system for an internal combustion engine, a leak test is carried out in order to confirm whether airtightness (or liquidtightness) is sufficiently secured. This leak test is usually performed in a state where an injector or the like is attached to the cylinder head and the fuel supply device is assembled. In the following, the fuel supply device in the assembled state as described above is referred to as a work.

Then, a leak test is usually carried out using the following leak tester. Here, the leak tester has a hollow container (hereinafter referred to as a master) that has the same volume as the work and is formed in a hermetically sealed state, and a fluid pressure (for example, an air pressure) of the same pressure on each of the work and the master. ) Is supplied, and a differential pressure leak tester for measuring an internal pressure difference between the master and the work is provided.

When air pressure is simultaneously supplied to the work and the master, if the work leaks fluid, a differential pressure is generated between the master and the work, and this differential pressure is detected by the differential pressure leak tester. Of. And this gives
The airtightness of the above-mentioned fuel supply device can be confirmed. By the way, in recent years, also in an internal combustion engine that mainly uses gasoline as fuel (hereinafter referred to as a gasoline engine), as in a diesel engine, a direct fuel injection internal combustion engine or a direct injection internal combustion engine that directly injects fuel into a cylinder. Institutions are proposed.

In such an in-cylinder injection type internal combustion engine, the fuel injection timing can be greatly changed according to the operating state of the engine, and the exhaust gas can be reduced while improving the performance of the engine. Become. Explaining the fuel supply device in such a cylinder injection type internal combustion engine, FIG. 4 is a schematic configuration diagram showing such a fuel supply device.

This fuel supply system is equipped with a fuel direct injection type internal combustion engine (cylinder injection type internal combustion engine) for directly injecting fuel into a cylinder (combustion chamber), and as shown in FIG. A fuel passage 7 that communicates with the tank 21 is provided. In the fuel passage 7, a fuel feed passage 7A that feeds fuel from the fuel tank 21 to the injector 6 and surplus fuel that has not been injected by the injector 6 are supplied to the fuel tank. It is composed of a fuel return passage 7B for returning to. A high pressure fuel pump 8 is provided in the fuel feed passage 7A. Further, the fuel is supplied to the injector 6 through the delivery pipe 6A, but here, the delivery pipe 6A itself is considered to be a part of the fuel passage 7.

The high-pressure fuel pump 8 pressurizes the fuel discharged from the low-pressure fuel pump (not shown) up to about several tens of atmospheres, and delivers the fuel to the delivery pipe 6A side. As a result, the fuel pressure on the upstream side of the high-pressure fuel pump 8 is increased to, for example, about 50 atmospheres. A high-pressure regulator 11 is provided in the downstream portion of the injector 6, that is, the fuel return passage 7B. The high-pressure regulator 11 is closed until the discharge pressure from the high-pressure fuel pump 8 exceeds a set pressure, and when the discharge pressure exceeds the set pressure, the excess pressure fuel is returned to the fuel tank side. Thus, the fuel pressure in the injector 6 is stabilized at a predetermined pressure.

Further, a bypass connecting the upstream side portion and the downstream side portion of the high pressure regulator 11 and the throttle 18 so that the fuel in the injector 6 portion can be discharged to the fuel tank side by bypassing the high pressure regulator 11. A passage 20 is provided. The bypass passage 20 is provided with the solenoid valve 10. The operation of the solenoid valve 10 is controlled by a controller (not shown). The solenoid valve 10 opens the bypass passage 20 when it is supplied with electric power and opens the bypass passage 20 when it is not supplied with electric power. Twenty is closed. Then, in this controller, the solenoid valve 10 is opened when the engine is started, and the solenoid valve 10 is controlled to be closed in the normal operation state (after the start).

[0009]

It is conceivable to perform a leak test in the fuel supply device for such a cylinder injection type internal combustion engine as in the leak test described above. That is, the upstream side of the fuel feed passage 7A (that is, the upstream side of the high-pressure fuel pump 8) of the fuel supply device as the work and the master are connected to an air pressure source, and the air pressurized by this air pressure source is used as fuel. It is conceivable to perform a leak test by simultaneously supplying the supply device and the master and detecting the occurrence of leakage with a differential pressure leak tester.

By the way, in a fuel supply system for a cylinder injection type internal combustion engine, the fuel pressure in the fuel supply system becomes high, and therefore it is necessary to perform a leak test at a high pressure. However, the high-pressure fuel pump provided in the fuel supply device for a direct injection internal combustion engine as described above can pressurize the fuel to a high pressure state by being driven by the engine, but from the outside of the pump (particularly, When a high-pressure working fluid acts (from the upstream side of the pump), the oil seal and the like may be damaged.

Therefore, in order to avoid such a situation,
It is conceivable to perform the leak test by connecting the air pressure source 3 to the fuel return passage 7B on the downstream side of the high-pressure regulator 11 and supplying pressurized air in the direction opposite to the fuel supply direction. That is, since the check valve for preventing the backflow of the fuel is provided in the fuel passage on the downstream side of the high-pressure fuel pump 8 as described above, the pressurized air is supplied from the downstream side of the high-pressure fuel pump 8. Then, the high-pressure fuel pump 8 should not be damaged.

However, when performing the leak test in this way, the solenoid valve 10 must be operated (opened) in order to supply the fluid pressure (eg, air pressure) from the fuel return passage 7B side. Therefore, it is necessary to apply a voltage to the solenoid valve 10, but in this case, heat is generated from the solenoid valve 10. For example, when a voltage is applied to the solenoid valve 10 for about 5 seconds, the temperature of the work rises by about 0.1 degree. Therefore, there is a problem in that a temperature difference occurs between the work and the master, and an accurate leak test cannot be performed.

Further, since the measurement error in the leak test caused by the temperature change generally increases as the fluid pressure during the leak test increases, it is necessary to perform the leak test in a state where the fluid pressure is high. In the engine fuel supply system, there is a problem that such a temperature change has a great influence on a measurement error in the leak test.

A technique relating to a leak test automation device is disclosed in Japanese Utility Model Laid-Open No. 3-110341, but this technique stops the pressure supply when the pressure exceeds a specified value, so that airtightness is maintained. It is not a technique for reducing measurement error due to temperature change in inspection, and cannot solve the above-mentioned problems. The present invention has been devised in view of the above problems, and a leak tester with a temperature error compensating function, which is capable of compensating a measurement error due to a temperature change of an object to be inspected and improving the accuracy of a leak test. The purpose is to provide.

[0015]

Therefore, the leak tester with a temperature error compensating function of the present invention as set forth in claim 1 applies a fluid pressure to an object to be inspected having a heat source to inspect the hermeticity of the object to be inspected. In the leak tester, a master having a predetermined internal volume and a heat capacity, a pressure source for supplying a fluid having substantially the same pressure to the inspection object and the master, and a fluid pressure supplied to the inspection object by the pressure source. And a measuring device for measuring a pressure difference between the master and the fluid pressure supplied to the master, and detecting the presence or absence of leakage of the inspected object to the outside based on the measurement result of the measuring device, and the inspected object. In order to compensate the measurement error due to the temperature change, the heating device for heating the master to a predetermined temperature is provided.

According to a second aspect of the leak tester with a temperature error compensation function of the present invention, in the apparatus according to the first aspect, the heat source is a valve device that electrically operates to generate heat. A leak tester with a temperature error compensating function according to a third aspect of the present invention is the apparatus according to the second aspect, wherein the master has substantially the same internal volume and heat capacity as the inspected object, and the heating device includes the valve. It is characterized in that the master is heated to substantially the same temperature as the temperature of the device under test when the device is energized.

A leak tester with a temperature error compensating function according to a fourth aspect of the present invention is the apparatus according to the third aspect, wherein the heating device has a conductor having substantially the same heating characteristics as the valve device, and the valve device. And an electric circuit for supplying the same electric current to the conductor. A leak tester with a temperature error compensating function according to a fifth aspect of the present invention is the apparatus according to the fourth aspect, wherein a plurality of pairs of the master and the conductors are provided and power is supplied to each conductor in the electric circuit. It is characterized in that a conductor changeover switch for changing over is provided.

According to a sixth aspect of the present invention, there is provided a leak tester with a temperature error compensating function according to the fourth or fifth aspect, wherein the electric circuit includes the valve device and the conductor with a minimum operating voltage of the valve device. Is configured to be applied. A leak tester with a temperature error compensating function according to the present invention according to claim 7 is the device according to any one of claims 4 to 6, wherein the electric circuit includes the valve device and the conductor, and a minimum operation of the valve device. It has a first circuit for applying a voltage, a second circuit for applying a minimum holding voltage of the valve device, and a voltage changeover switch for switching between the first circuit and the second circuit. I am trying.

According to an eighth aspect of the present invention, there is provided a leak tester having a temperature error compensating function according to any one of the second to seventh aspects, in which the device under test is a fuel supply device used in an internal combustion engine for automobiles. The fuel supply device includes a fuel injection device, a fuel pump for delivering fuel to the fuel injection device, and a fuel return passage for returning surplus fuel in the fuel injection device to a fuel tank. It is characterized in that it is arranged in the return passage.

According to a ninth aspect of the present invention, there is provided a leak tester having a temperature error compensating function, wherein the internal combustion engine is a fuel direct injection type internal combustion engine for directly injecting fuel into a combustion chamber. The valve device is configured to accelerate the discharge of the fuel remaining in the fuel injection device by opening the valve when the amount of fuel delivered from the fuel pump is equal to or less than a predetermined value.

According to a tenth aspect of the leak tester with a temperature error compensating function of the present invention, in the apparatus according to any of the first to ninth aspects, the fluid pressure is pneumatic pressure.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a leak tester with a temperature error compensating function according to an embodiment of the present invention, and FIG. FIG. 3 is a schematic configuration diagram showing (inspection object), and FIG. 3 is a diagram showing heat generation characteristics of the solenoid valve.

In FIGS. 1 and 2, 1 is a fuel supply device as a work (inspection object) having a heat source, 2 and 39 are masters, 3 is an air pressure source (pressure source), and 4 is a differential pressure leak tester. (Measuring device), 5 is a flow meter (measuring device),
6 is a fuel injection valve (hereinafter referred to as an injector) as a fuel injection device, 7 is a fuel passage, 8 is a high-pressure fuel pump (fuel pump) provided upstream of the fuel passage 7, 9, 1
4, 15 are check valves, 10 is an electromagnetic valve (solenoid valve) as a valve device that electrically operates and generates heat, 11 is a high pressure regulator, 12 and 16 are fuel filters, 13, 1
7, 18 are throttles, 30 is a heating device, 31 and 40 are solenoid valves (conductors), 32 is an electric circuit, 33 is a main switch of the electric circuit 32, 34 is a voltage changeover switch, 35 is a conductor changeover switch, 36 Is a switching valve (electromagnetic valve) for switching the supply destination of the pressurized air from the air pressure source 3.

First, in the leak tester according to the embodiment of the present invention, the fuel supply device 1 as a work is shown in FIG.
It will be described based on. The fuel supply device 1 is provided with a fuel direct injection internal combustion engine (cylinder injection internal combustion engine) that directly injects fuel into a cylinder (combustion chamber), and as shown in FIG. 1, an injector 6 and a fuel tank ( (Not shown) is provided with a fuel passage 7 that communicates with a fuel feed passage 7A that feeds fuel from the fuel tank to the injector 6 and excess fuel that has not been injected by the injector 6. It is composed of a fuel return passage 7B for returning to the tank. A high pressure fuel pump 8 is provided in the fuel feed passage 7A. Further, the fuel is supplied to the injector 6 through the delivery pipe 6A, but here, the delivery pipe 6A itself is considered to be a part of the fuel passage 7.

The operation of the injector 6 is computer controlled so that a required fuel injection amount can be obtained at a required timing in accordance with the engine speed, the intake air amount, and the like. The high-pressure fuel pump 8 pressurizes the fuel discharged from the low-pressure fuel pump (not shown) to about several tens of atmospheres, and delivers the fuel filtered by the fuel filter 12 to the delivery pipe 6A side. This allows
The fuel pressure on the upstream side of the high-pressure fuel pump 8 is increased to, for example, about 50 atmospheres.

The high-pressure fuel pump 8 has a portion to which high pressure cannot be applied (a portion to which high-pressure fluid cannot be applied) such as an oil seal. Also, the fuel feed passage 7A
A check valve 9 is provided on the downstream side of the high-pressure fuel pump 8 to prevent the reverse flow of the fuel delivered from the high-pressure fuel pump 8. The check valve 9 is composed of, for example, a steel ball and a steel sheet.

Further, the downstream portion of the injector 6, that is,
The high pressure regulator 1 is installed in the fuel return passage 7B of the fuel passage 7.
1 is provided. The high-pressure regulator 11 is closed until the discharge pressure from the high-pressure fuel pump 8 exceeds a set pressure, and when the discharge pressure exceeds the set pressure, the excess pressure fuel is returned to the fuel tank side. Thus, the fuel pressure in the injector 6 is stabilized at a predetermined pressure. Here, the above-mentioned set pressure is set to, for example, about 5 MPa (that is, about 50 atm) in consideration of combustion stability and fuel consumption. Further, a diaphragm 18 is provided on the downstream side of the high pressure regulator 11.

On the other hand, the upstream side portion and the downstream side portion of the high pressure fuel pump 8 are connected so that the fuel passing through the fuel feed passage 7A of the fuel passage 7 can be fed to the injector 6 by bypassing the high pressure fuel pump 8. A bypass passage 19 is provided. The bypass passage 19 has a fuel feed passage 7A.
Check valve 14 for passing fuel only from the upstream side to the downstream side of
Is provided. If the high pressure fuel pump 8 does not operate sufficiently and the downstream side of the high pressure fuel pump 8 has a lower fuel pressure than the upstream side of the check valve 14, the non-return valve 14 will not operate.
The bypass passage 19 is closed when 9 is opened and the high-pressure fuel pump 8 operates sufficiently and the fuel pressure on the downstream side of the high-pressure fuel pump 8 becomes higher than that on the upstream side.

A throttle 13 is also provided between the bypass passage 19 and the high pressure fuel pump 8. Further, the fuel in the injector 6 portion can be discharged to the fuel tank side by bypassing the high pressure regulator 11.
A bypass passage 20 that connects the upstream side portion and the downstream side portion of the high-pressure regulator 11 and the throttle 18 is provided. The bypass passage 20 is provided with a solenoid valve 10 for adjusting the discharge pressure from the high-pressure fuel pump 8 to a set pressure, and a throttle 17 is provided immediately downstream of the solenoid valve 10.

Further, the high-pressure fuel pump 8 and the bypass passage 2
A fuel discharge passage 7C for discharging fuel from the drain chamber in the high-pressure fuel pump 8 to the outside is provided between the fuel discharge passage 7C and 0.
The check valve 1 is provided in the fuel discharge passage 7C in order to prevent high pressure from being applied to the high-pressure fuel pump 8 at the time of checking the tightness.
5 are provided. The check valve 15 has the same structure as the check valve 9.

A fuel filter 16 is provided in the fuel return passage 7B upstream of the bypass passage 20 and the high pressure regulator 11. The operation of the solenoid valve 10 is controlled by a controller (not shown), and the bypass passage 20 is provided while receiving power supply.
Is opened, and the bypass passage 20 is closed when the power supply is cut off. Then, in this controller, the solenoid valve 10 is opened when the engine is started, and the solenoid valve 10 is controlled to be closed in the normal operation state (after the start).

This is because the fuel remaining on the downstream side of the delivery pipe 6A is discharged at the last engine stop. That is, when the engine is switched from the operating state to the engine stopped state, the high-temperature and high-pressure fuel remains in the delivery pipe 6A and the fuel return passage 7B. Vapor (air bubbles) is generated, and when the engine is operated next time, the pressure in the delivery pipe 6A and the fuel return passage 7B does not rise easily and the startability is deteriorated.
Therefore, the solenoid valve 10 is provided in the bypass passage 20 as described above, and the solenoid valve 10 is opened at the time of starting.

By the way, such a fuel supply system is designed to be used in a cylinder injection type internal combustion engine for an automobile. Therefore, the solenoid valve 10 is usually operated by the voltage of the automobile battery (generally 12V). Are controlled. When such a relatively high voltage (12V) acts on the solenoid valve 10, a large amount of heat is generated from the solenoid valve 10, and the solenoid valve 10 becomes a heat source in the work (inspection object) 1.

Here, the temperature characteristics due to the applied voltage of the solenoid valve 10 will be described with reference to FIG. The vertical axis of FIG. 3 indicates the temperature (° C.), and the horizontal axis indicates the time (second). Line A shows the temperature characteristics when a voltage of 4 V is applied to the solenoid valve 10 as the lowest voltage that can maintain the operating state,
Line B shows the temperature characteristic when a voltage of 7V is applied as the minimum voltage required to operate the solenoid valve 10, and line C shows the temperature characteristic when a voltage of 12V is applied to the solenoid valve 10. .

According to this, when the voltage is applied to the solenoid valve 10, the temperature difference is not so large, but if the voltage application is continued, the temperature difference increases with time.
That is, when the voltage of 12 V is continuously applied to the solenoid valve 10, the temperature rises rapidly as shown by the line C. On the other hand, when the voltage of 7 V is continuously applied to the solenoid valve 10, it is understood that the temperature rise is relatively small as shown by the line B. Further, when the voltage of 4 V is continuously applied to the solenoid valve 10, it can be seen that almost no temperature rise is observed as shown by the line B. In addition, the solenoid valve 1
Even if a relatively low voltage of 4 V or 7 V is applied to 0, some temperature change will occur.

Therefore, in the present invention, by providing the heating device 30 in the leak tester, the temperature error due to the heat generation of the solenoid valve 10 during the leak test is compensated. The heating device 30 will be described in detail later. Next, the master 2, 39, the air pressure source 3, the differential pressure leak tester 4, the flow meter 5, and the heating device 30 in the leak tester according to the embodiment of the present invention will be described in order.

Master 2 (hereinafter referred to as first master 2)
Is configured to have the same internal volume and heat capacity as the fuel supply device 1 as a work. Further, the leak tester of the present embodiment is provided with a master 39 (hereinafter, referred to as a second master) configured similarly to the first master 2. The fuel supply device 1 is made of the same material (in this example, an aluminum alloy) in consideration of the measurement error due to the thermal conductivity.

The air pressure source 3 is a high-pressure pump device for pressurizing air to a high pressure, and includes the fuel supply device 1 and the first
Is configured to be able to supply air of the same pressure to the master 2 (or the second master 39) of the high pressure fuel pump 8 during normal operation of the fuel supply device 1.
It is configured so that pressurized air equivalent to the pressure (for example, 50 to 60 atmospheric pressure) applied to the downstream side of the is supplied.

Further, the air pressure source 3 is connected to the fuel supply system 1 via the differential pressure leak tester 4 and the first air supply passage 38A.
Is connected to the fuel return passage 7B. Further, the air pressure source 3 includes the differential pressure leak tester 4 and the second air supply passage 38.
It is connected to the first master 2 via B and is connected to the second master 39 via the differential pressure leak tester 4 and the third air supply passage 38C. Further, the second air supply passage 38B and the third air supply passage 38C are connected via an electromagnetic valve 36, and the supply of the pressurized air can be switched by the electromagnetic valve 36.

The differential pressure leak tester (measuring device) 4 is a pressure difference between the air pressure (fluid pressure) supplied to the fuel supply device 1 by the air pressure source 3 and the air pressure supplied to the first master 2 (ie, external pressure). Pressure difference caused by leak and internal leak)
The pressure difference detected by the differential pressure leak tester 4 is converted into a flow rate. The external leak means a leak from the fuel supply device 1 to the outside, and the internal leak means a leak inside the fuel supply device 1. Here, as a case where the internal leak occurs, for example, a leak from the check valves 9 and 14 of the fuel supply device 1 can be considered.

On the other hand, the flow meter (measuring device) 5 is for measuring the amount of fluid leaked inside the fuel supply device 1. The flow meter 5 is a fuel feed passage 7A of the fuel supply device 1 and is connected to the upstream side of the high pressure fuel pump 8, and the upstream side of the high pressure fuel pump 8 is open to the atmosphere. That is, the high-pressure fuel pump 8 itself pressurizes the low-pressure fuel on the upstream side to a high pressure and discharges it to the downstream side. However, when a high-pressure working fluid acts from the outside, a seal portion (not shown) or the like is generated. May be damaged. This is because, during normal use of the high-pressure fuel pump 8, no high pressure is applied to the high-pressure fuel pump 8 from the outside, so that the high-pressure fuel pump 8 itself does not need excessive pressure resistance. Therefore, in a portion where high pressure does not act during normal use of the high-pressure fuel pump 8 (for example, the downstream seal portion), sufficient pressure resistance performance for the leak test is not ensured and high-pressure fluid may be applied. You can't.

Therefore, while opening the upstream side of the high-pressure fuel pump 8 to the atmosphere to protect the high-pressure fuel pump 8, the flow meter 5 detects the amount of air leaked internally from the check valves 9, 14, 15. -ing The heating device 30 is
The first master 2 is heated to the same temperature as the temperature of the fuel supply device 1 when the solenoid valve 10 is energized.
The electromagnetic valves 31 and 40 having the same heating characteristics as those of the above, and the electric circuit 32 that energizes these electromagnetic valves 31 and 40 and the electromagnetic valve 10 with the same value are provided.

This electric circuit 32 has a minimum operating voltage application circuit section (first circuit) 32C for applying a minimum voltage (for example, 7V) required to operate the solenoid valve 10.
And a minimum holding voltage application circuit section (second circuit) 32D for applying a minimum required voltage (for example, 4V) to maintain the valve open state of the solenoid valve 10, and further, It has a first conductor circuit portion 32A and a second conductor circuit portion 32B that can be switched to either of them by the body changeover switch 35.

Here, in the first conductor circuit portion 32A,
The same solenoid valve 31 as the solenoid valve 10 of the fuel supply device 1 is provided, and this solenoid valve 31 is attached to the master 2. Further, the second conductor circuit portion 32B is provided with the same solenoid valve 40 as the solenoid valves 10 and 31, and the solenoid valve 40 is attached to the master 39. Further, the minimum operating voltage applying circuit section 32C is provided with a voltage changeover switch 34 so that the minimum operating voltage applying circuit section 32C and the minimum holding voltage applying circuit section 32D can be switched.

Further, the minimum holding voltage applying circuit section 32D is provided with a resistor 37, and the voltage changeover switch 34 is switched to the minimum operating voltage applying circuit section 32C side by the action of the resistor 37. Rather, the voltage of the solenoid valve 10 and the solenoid valve 31 or the solenoid valve 40 is set to be lower when switched to the minimum holding voltage application circuit 32D side.

The main switch 33 controls ON / OFF of power supply to the solenoid valve 10 and the solenoid valve 31 or the solenoid valve 40. Reference numeral 50 denotes a relay, which operates the solenoid valve 10 by turning on the main switch 33. Since the leak tester as one embodiment of the present invention is configured as described above, the leak test can be performed as described below.

When conducting a leak test using the first master 2, the conductor selector switch 35 is switched to the first conductor circuit section 32A side (that is, the first master 2 side), and the solenoid valve 36 is turned on. Switching to the second air supply passage 38B side (that is, the first master 2 side). If the main switch 33 is turned on under such a state, the solenoid valve 10 is opened by applying the minimum operating voltage (7 V) to the solenoid valve 10 of the fuel supply device 1, and the first valve is opened. A voltage of 7V is also applied to the solenoid valve 31 of the master 2. That is, the main switch 33 and the voltage changeover switch 34
By turning on both, the solenoid valve 10 is operated (opened)
The minimum required voltage of 7V is applied to the solenoid valve 10, and the solenoid valve 31 is also applied with a voltage of 7V.

Thereafter (after about 1 second), the applied voltage of both is dropped to the minimum operating voltage (for example, 4 V) capable of maintaining the operating state of the solenoid valves 10 and 31, and the leak test is started.
That is, by turning off the voltage changeover switch 34, the applied voltage to both the solenoid valves 10 and 31 is set to 4V,
The leak test is started in this state. As a result, the operating voltage of the solenoid valve 10 can be significantly reduced,
The generation of heat from the solenoid valve 10 can be suppressed.

Further, by setting the fuel supply device 1 and the first master 2 or the second master 39 under the same condition, the fuel supply device 1 and the first master 2 or the second master 39 are connected to each other. There is also an advantage that measurement error due to temperature change can be reduced. Further, when the leak test is continuously performed for another fuel supply device 1 after the leak test for the fuel supply device 1 is completed, the conductor changeover switch 35 is set to the second conductor circuit portion 32B side (that is, the second conductor circuit 32B). Of the solenoid valve 36.
To the third air supply passage 38C side (that is, the second master 39
The leak test is performed by using the second master 39 by switching to the side). This is because the first master 2 has heat from the immediately preceding leak test.

When the fuel supply device 1 which has not passed the leak test is continuously retested, the first master 2 or the second master used in the immediately preceding leak test is used.
The master 39 is used to perform the leak test. That is, the conductor changeover switch 35, the solenoid valve 36
Don't switch, but do the leak test continuously. This is because the master and the fuel supply device have the same amount of heat.

Since two pairs of masters, the first master 2 and the second master 39, are provided, the fuel supply device 1 and the master 2 can be used even when the leak test is continuously performed on another inspection object. , 39, the initial temperature difference can be reduced. In the leak tester of the present embodiment, the work is the fuel supply device,
This leak tester is wide and can be used for those requiring a tightness test, and is considered to have a high utility value especially for those requiring high pressure.

In the leak tester of this embodiment, the minimum operating voltage of the solenoid valves 10, 31, 40 is 7V and the minimum holding voltage is 4V.
0 can be operated, and if the temperature change can be suppressed low and the influence of heat in the leak test can be suppressed while maintaining the operating state, voltage other than these can be applied. Good.

Further, in the leak tester of this embodiment, two pairs of the master and the heating device are provided, but the invention is not limited to this, and a plurality of pairs may be provided. Furthermore, in the leak tester of this embodiment,
Although air pressure is used as the fluid pressure, it is not limited to this, and other fluid pressure, such as hydraulic pressure, may be used.

[0054]

As described above in detail, according to the leak tester with the temperature error compensating function of the invention described in claim 1, it is possible to reduce the measurement error due to the temperature change between the object to be inspected and the master. There are advantages. According to the leak tester with temperature error compensating function of the invention described in claim 2, in addition to the effect described in claim 1, in the valve device which electrically operates and generates heat, the temperature between the object to be inspected and the master is increased. There is an advantage that the measurement error due to the change can be reduced.

According to the leak tester with a temperature error compensating function of the present invention described in claim 3, in addition to the effect described in claim 2, there is an advantage that a more accurate leak test can be performed with a simple configuration. According to the leak tester with temperature error compensating function of the present invention described in claim 4,
In addition to the effects described, the inspected object and the master have the same amount of heat, which is advantageous in that a more accurate leak test can be performed.

According to the leak tester with a temperature error compensating function of the present invention described in claim 5, in addition to the effect of claim 4, even when a leak test is continuously performed on another test object, the test object is tested. The advantage is that the initial temperature difference between the master and the master can be reduced. According to the leak tester with a temperature error compensating function of the present invention described in claim 6, in addition to the effect of claim 4 or 5, there is an advantage that heat generation from the valve device can be suppressed.

According to the leak tester with temperature error compensation function of the invention described in claim 7, in addition to the effect described in any one of claims 4 to 6, the heat generation from the valve device can be greatly suppressed. There are advantages. According to the leak tester with a temperature error compensating function of the present invention described in claim 8,
In addition to the effect described in any of 1 to 7, there is an advantage that in the fuel supply device, a measurement error due to a temperature change between the fuel supply device and the master can be reduced.

According to the leak tester with temperature error compensating function of the present invention as defined in claim 9, in addition to the effect as defined in claim 8, in the fuel direct injection internal combustion engine for directly injecting fuel, fuel supply There is an advantage that the measurement error due to the temperature change between the device and the master can be reduced. According to the leak tester with a temperature error compensating function of the invention described in claim 10, in addition to the effect described in any one of claims 1 to 9, there is an advantage that the leak detection capability is high and the cost is low. .

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a leak tester with a temperature error compensation function according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a fuel supply device as a work (inspection object) in a leak tester with a temperature error compensating function according to an embodiment of the present invention.

FIG. 3 is a diagram showing heat generation characteristics of a solenoid valve used in a fuel supply device as a work (inspection object) in a leak tester with a temperature error compensation function according to an embodiment of the present invention.

FIG. 4 is a schematic configuration diagram showing an example of a fuel supply device for an internal combustion engine.

[Explanation of symbols]

 1 Fuel Supply Device as Workpiece (Inspection Object) 2, 39 Master 3 Air Pressure Source (Pressure Source) 4 Differential Pressure Leak Tester (Measuring Device) 5 Flowmeter (Measuring Device) 6 Injector (Fuel Injecting Device) 6A Delivery Pipe 7 Fuel passage 7A Fuel feed passage 7B Fuel return passage 8 High-pressure fuel pump 9, 14, 15 Check valve 10 Electromagnetic valve (valve device that electrically operates to generate heat) 11 High-pressure regulator 12, 16 Fuel filter 13, 17, 18 Throttle 19, 20 Bypass passage 21 Fuel tank 30 Heating device 31, 40 Electromagnetic valve (conductor) 32 Electric circuit 32A First conductor circuit portion 32B Second conductor circuit portion 32C Minimum operating voltage application circuit portion (first Circuit) 32D minimum holding voltage application circuit section (second circuit) 33 main switch of electric circuit 32 34 voltage switching switch 35 conductor selector switch 36 solenoid valve 37 resistor 38A first air supply passage 38B second air supply passage 38C third air supply passage 50 relay as a switching valve

Claims (10)

[Claims] 1. A leak tester for inspecting the hermeticity of an inspected object by applying fluid pressure to the inspected object having a heat source, a master having a predetermined internal volume and heat capacity, the inspected object and the master. And a measuring device for measuring a pressure difference between a fluid pressure supplied to the device under test by the pressure source and a fluid pressure supplied to the master. A heating device is provided for detecting whether or not there is a leak to the outside of the inspection object based on the measurement result of the measurement device, and for heating the master to a predetermined temperature in order to compensate the measurement error due to the temperature change of the inspection object. A leak tester with a temperature error compensation function. 2. The leak tester with a temperature error compensating function according to claim 1, wherein the heat source is a valve device that electrically operates to generate heat. 3. The master has substantially the same internal volume and heat capacity as the object to be inspected, and the heating device heats the master to a temperature substantially the same as the temperature of the object to be inspected when the valve device is energized. The leak tester with a temperature error compensating function according to claim 2, wherein the leak tester has a temperature error compensating function. 4. The heating device includes an electric conductor having substantially the same heating characteristics as the valve device, and an electric circuit for energizing the valve device and the electric conductor to the same value. The leak tester with a temperature error compensating function according to claim 3. 5. A plurality of pairs of the master and the conductor are provided, and a conductor changeover switch that switches power supply to each conductor is provided in the electric circuit. Leak tester with temperature error compensation function described. 6. The temperature error according to claim 4, wherein the electric circuit is configured to apply a minimum operating voltage of the valve device to the valve device and the electric conductor. Leak tester with compensation function. 7. A first circuit, wherein the electric circuit applies a minimum operating voltage of the valve device to the valve device and the conductor, and a second circuit that applies a minimum holding voltage of the valve device. The leak tester with a temperature error compensating function according to any one of claims 4 to 6, further comprising a voltage changeover switch for switching between the first circuit and the second circuit. 8. The inspected object is a fuel supply device used in an internal combustion engine for an automobile, the fuel supply device, a fuel injection device, a fuel pump for delivering fuel to the fuel injection device, and the fuel. 8. A temperature error compensation according to claim 2, further comprising a fuel return passage for returning excess fuel in the injector to the fuel tank, and the valve device is arranged in the fuel return passage. Leak tester with functions. 9. The internal combustion engine is configured as a fuel direct injection type internal combustion engine that directly injects fuel into a combustion chamber, and the valve device opens when the amount of fuel delivered from the fuel pump is below a predetermined value. The leak tester with a temperature error compensating function according to claim 8, wherein the leak tester is configured to accelerate the discharge of the fuel remaining in the fuel injection device. 10. The leak tester with a temperature error compensating function according to claim 1, wherein the fluid pressure is air pressure.