WO2016159409A1

WO2016159409A1 - Method for inspecting for coolant leakage

Info

Publication number: WO2016159409A1
Application number: PCT/KR2015/003221
Authority: WO
Inventors: 오창복; 권혁환; 배지원
Original assignee: 태원물산 주식회사
Priority date: 2015-03-31
Filing date: 2015-03-31
Publication date: 2016-10-06
Also published as: KR20160116901A

Abstract

The present invention comprises the steps of: injecting compressed air into an inspection area of a body being inspected, and determining whether air is leaking therefrom by changes in the pressure and temperature values of the compressed gas; if air is determined to be leaking from the body being inspected, then measuring the amount of air being leaked therefrom; and converting the measured air leakage amount to a coolant leakage amount.

Description

How to test for coolant leak

The present invention relates to a cooling water leak inspection method, and more particularly to a cooling water leakage inspection method for inspecting the leakage amount of the cooling water based on the air leakage amount of the test object.

Background Art Conventionally, in producing a product or a part that requires leakage prevention, it is determined whether or not there is a leak on the production process line to determine whether the product is defective.

In particular, sealing in parts using working fluid is an important factor in terms of preventing aging and failure of component parts. For example, when a leak occurs in a finished vehicle to which an automotive part using working fluid is applied, The problem arises that the operation itself becomes impossible. Therefore, a leak test is performed on the production process line of the automotive parts in which the working fluid is used. However, when a liquid such as water is used, problems such as rust may occur before the engine is mounted. Normally, air is used for leak testing. In particular, as the standards for air leakage allowances have recently been strengthened, for example, in the case of water pumps, the standards that were 8 cc / min or less at 1.5 bar of air pressurization were strengthened to 1 cc / min or less at the same air pressurization. There is a trend.

On the other hand, the air leakage test for automobile parts uses a flow rate or a differential pressure type, but the differential pressure air leakage test is used because it is difficult to install a flowmeter because the sealing area is wide and the leakable area is many places. do.

Differential pressure leak tests currently used for automotive parts typically press the final product tightly onto the leak test jig and then pressurize the test product formed between the final product and the jig at a pressure of typically 1.5 bar through a compressed air inlet. Is done by injecting the air. In the state where the compressed air in the inspection region was maintained at the predetermined pressure at the start of the inspection, the differential pressure from the initial pressure was confirmed after a predetermined time had elapsed through the leak detection unit, and the control unit of the air leakage tester was converted into a constant value from the differential pressure value. Convert air leakage through the equation.

This converted air leakage amount value is compared with a reference value, and it is judged that it is bad if this reference value is abnormal. On the other hand, in the case of the air used in the conventional differential pressure air leakage test, the compressed air is introduced into the inspection area inside the sealed jig by using a compressor, the compressed air rises above the initial temperature during the compression process, in particular the detection time While the temperature of the compressed air inside the jig changes depending on the external environment such as seasonal factors, this causes serious problems in detection accuracy and detection reliability. In addition, in some cases, there is a problem that the defective product is leaked out to become a factor to increase the quality cost, or the regular product is mistaken as a defective product to increase the loss cost.

Moreover, in the conventional differential pressure leakage test, since it is judged only by the amount of air leakage, it was insufficient to judge the amount by which the coolant can actually leak.

Background art of the present invention is disclosed in Korean Patent Laid-Open No. 2012-0013526 (2012.02.15, leak inspection apparatus and method).

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a cooling water leakage inspection method for inspecting the leakage of cooling water based on the air leakage of the inspected object.

Another object of the present invention is to provide a cooling water leakage test method to improve the reliability of the leak test results, and to determine whether or not to accurately leak the test object.

Cooling water leakage test method according to an aspect of the present invention comprises the steps of injecting compressed air into the inspection region of the inspected object to determine whether the air leaks from the inspected object by the change in the pressure value and temperature value of the compressed air; If it is determined that the air leaks from the inspected object, measuring the amount of air leaked from the inspected object; And converting the measured air leakage into cooling water leakage.

In the present invention, the step of determining whether the air leaks from the test subject comprises the steps of storing compressed air such that the air pressure inside the air cylinder has a first pressure value; Adjusting the temperature of the compressed air stored in the air cylinder to satisfy a first temperature value; Injecting the compressed air stored in the air cylinder into an inspection region formed between a jig and a test object; And detecting the leakage of the inspected object by detecting a change in the pressure value and the temperature value of the compressed air in the inspection region.

In the present invention, the step of determining whether the test object is leaking comprises the steps of measuring the pressure value and the temperature value of the compressed air in the inspection area; Measuring a change in pressure and temperature of the compressed air inside an inspection area; Calculating an air leakage amount of the inspected object by using a change in pressure and temperature of the compressed air in the inspection region; And determining that leakage occurs in the inspected object when the calculated air leakage amount is greater than or equal to a set value.

In the present invention, further comprising the step of finally determining the coolant leakage based on the coolant leakage amount.

In the present invention, the final step of determining the coolant leakage based on the coolant leakage amount, the leakage of the coolant leakage if the time when the total amount of coolant of the coolant occurs by a predetermined set amount within the predetermined set time when leaked by the coolant leakage amount It is characterized by determining.

The present invention can estimate the leakage portion and the leakage amount of the cooling water based on the air leakage amount of the test subject.

In addition, the present invention can minimize the inspection area and minimize the temperature change of the compressed air during the inspection time, thereby reducing the air leakage deviation, it is possible to improve the detection reliability and detection accuracy. In addition, by reducing the customer leakage of defective parts and errors that determine the regular goods as defective goods, it has the effect of minimizing the quality cost and reducing the cost.

1 is a block diagram showing a cooling water leak auditing apparatus according to an embodiment of the present invention.

2 is a block diagram illustrating a coolant leakage test apparatus according to another exemplary embodiment of the present invention.

3 is a flow chart showing a cooling water leak inspection method according to an embodiment of the present invention.

Hereinafter, a coolant leakage inspection method according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this process, the thickness of the lines or the size of the components shown in the drawings may be exaggerated for clarity and convenience of description. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to the intention or convention of a user or an operator. Therefore, the definitions of these terms should be made based on the contents throughout the specification.

1 is a block diagram showing a coolant leakage test apparatus according to an embodiment of the present invention.

First, the derivation process of the conversion equation used in the cooling water leakage test method according to an embodiment of the present invention will be described. In this embodiment, the compressed air used is set as an ideal gas in the inspection region, and therefore, the compressed air in the inspection region satisfies the following ideal gas state equation (Equation 1).

Equation 1

Where P is the pressure of the gas, V is the volume of the gas, m is the mass of the gas, R is the gas constant, and T is the absolute temperature. Therefore, the mass m of the gas may be expressed as in Equation 2 below.

Equation 2

Here, when both sides are differentiated with respect to time, the volume in the inspection area is constant with respect to the change in time, and can be expressed as in Equation 3 below.

Equation 3

In the case of integrating both sides of the equation (3) with respect to time, the volume in the inspection area is V ₁ , the temperature in the inspection initial jig is T ₁ , the pressure in the inspection initial jig is P ₁ , and the temperature in the jig after the time t is elapsed. If T ₂ , the pressure in the jig is P ₂ , and the amount of change in pressure when t time elapses is P and the amount of change in temperature is T, the following equation (4) can be expressed.

Equation 4

Therefore, the leakage amount per unit time is as follows.

Equation 5

Equation 6

Where V1 is the volume in the test area, is the density of compressed air, T ₁ is the temperature of the compressed air in the test area at the start of the test, T ₂ is the temperature of the compressed air in the test area at the end of the test, and P ₁ is the test start. The pressure of the compressed air in the inspection region at the time of test, P ₂ is the pressure of the compressed air in the inspection region at the end of inspection, t is the inspection time.

Table 1 below shows the calculation result in the conversion equation considering the temperature change of the compressed air when the allowable air leakage is 1 cc / min using the above equation. As can be seen from Table 1, when the allowable air leakage amount is 1 cc / min or less, when the test compressed air rises 5 times in the jig during the detection time compared to the case where the temperature is the same in the jig (Case 3), the indicated air leakage amount is about 1 cc / min was reduced (Case 4), and when the temperature dropped 5, the indicated air leakage increased by about 1 cc / min (Case 5).

Table 1

Exam conditions	case1	case2	case3	case4	case5
Allowable leakage	8cc / min	1 cc / min	1 cc / min	1 cc / min	1 cc / min
Inspection volume (V1)	200 cc	200 cc	200 cc	200 cc	200 cc
Test pressure (P1)	1.5bar	1.5bar	1.5bar	1.5bar	1.5bar
Initial temperature (T1)	298K	298K	298K	298K	298K
Detection time (t)	5sec	5sec	5sec	5sec	5sec
Pressure (after completion of detection time)	1.3 bar	1.475 bar	1.495 bar	1.495 bar	1.495 bar
Temperature after completion of detection time	298K	298K	298K	303K	293K
Leakage	7.77 cc / min	0.971 cc / min	0.194cc / min	-0.767 cc / min	1.188cc / min

Therefore, in order to improve the detection accuracy, it is necessary to keep the temperature of the inspection region in the jig constant during the detection time. Hereinafter, the coolant leakage inspection apparatus according to the present embodiment for maintaining a constant temperature of the inspection region in the jig during the detection time will be described.

Referring to FIG. 1, the coolant leak test apparatus according to an exemplary embodiment of the present invention may include a compressor 11, a regulator 12, a compressed air injection unit 10, an air cylinder 31, and a first temperature sensor 33. Compressed air temperature control unit 37 including the first pressure sensor 35, a jig 21 for fixing the inspected object 22, and a pressure sensor 41 measuring pressure in the jig 21. , A control unit 42, a conversion unit 50, and an air leakage measurement unit 60.

The compressed air inlet is composed of a compressor 11 and a regulator 12. The compressor 11 pressurizes the gas to generate compressed air, and the regulator 12 adjusts the compressed air to the air pressure necessary for the leak test and delivers it to the air cylinder 31.

In the case of large compressors used in work lines, it is preferable to use a separate small compressor if there is a concern that the temperature change of the compressed air will be large due to excessive air compression.

The compressed air passing through the regulator 12 is injected into the air cylinder 31, and the compressed air is injected until the pressure inside the air cylinder 31 reaches the air pressure required for the leak test. The air cylinder 31 temporarily stores compressed air therein, and has a temperature control device to adjust the temperature of the stored compressed air to satisfy a predetermined temperature range.

On the other hand, at least one cooling fin 32 is formed on the outer surface of the air cylinder 31 shown in FIG. The cooling fin 32 improves the heat conduction efficiency between the air cylinder 31 and the outside air and, by natural convection, rapidly changes the temperature of the compressed air inside the air cylinder 31 within a predetermined range, for example, within 0.1 range of the outside air temperature. Act to regulate them. Therefore, in the cooling water leak inspection apparatus according to an embodiment of the present invention, by leaving the compressed air stored in the air cylinder 31 for a predetermined time, the temperature of the compressed air can be adjusted to have a value substantially equal to the outside temperature. There is no need for a separate complicated temperature control device to control the temperature of the compressed air. Therefore, manufacturing cost, the management cost of an inspection apparatus, etc. can be reduced.

On the other hand, the air cylinder 31 is the first pressure sensor 35 to measure the pressure inside the air cylinder 31 and the first temperature sensor 33 that can measure the temperature inside the air cylinder 31. It is provided. In addition, the coolant leak test apparatus according to an embodiment of the present invention includes a second temperature sensor 51 capable of measuring the outside temperature, so that the measured value of the first temperature sensor 33 and the second temperature sensor ( In contrast to the measured value by 51), it is possible to determine whether or not the temperature inside the air cylinder 31 is within a predetermined range of the outside air temperature, for example, 0.1 range of the outside air temperature.

In addition, the coolant leakage inspection apparatus according to an embodiment of the present invention includes a jig 21 for fixing the inspected object 22, which is a product to be inspected, and forming an inspection region 23 therein. The inspection region 23 refers to a closed space formed between the jig 21 and the inspected object 22 when the inspected object 22 is fixed to the jig 21, and compressed air is discharged from the air cylinder 31. It is the space to be injected. The jig 21 may be provided with a separate sealing device (not shown) or a clamping device (not shown) to fix the subject 22 to the jig 21. In addition, the jig 21 is a second pressure sensor 41 for measuring the pressure of the inspection region 23 inside the jig 21 and a third temperature sensor 24 for measuring the temperature of the inspection region 23. Equipped with.

The third temperature sensor 24 may be composed of a plurality of temperature sensors, and preferably, the plurality of temperature sensors may be disposed in a direction facing each other diagonally on the wall of the jig 21. In this case, by comparing the measured values of the plurality of temperature sensors, it is possible to determine whether or not the temperature distribution of the inspection region 23 inside the jig 21 is constant.

Opening and closing of the pipeline connecting the jig 21 and the air cylinder 31 of the coolant leakage inspection apparatus according to the exemplary embodiment of the present invention is controlled by the valve 34. The valve 34 remains closed until the temperature inside the air cylinder 31 satisfies a predetermined range, but opens when the temperature inside the air cylinder 31 satisfies a predetermined range, for example, within 0.1 range of the outside air temperature. Compressed air can be transferred from the air cylinder 31 to the inspection region 23 of the jig 21. On the other hand, when the pressure inside the inspection region 23 of the jig 21 reaches the pressure necessary for the leakage inspection, the valve 34 is closed to prevent the compressed air from being transferred from the air cylinder 31 into the inspection region 21. do.

On the other hand, in the case of the pipeline connecting between the jig 21 and the air cylinder 31, if the length is longer, there is a possibility that the temperature change may increase due to the influence of the outside air during the injection of compressed air bar length It needs to be minimized. In addition, since the inspection area 23 inside the jig 21 includes a pipeline connecting the valve 34 and the jig 21, in order to reduce the loss of compressed air, the inspection area can be minimized. The valve is preferably arranged as close to the jig 21 as possible.

In the coolant leak test apparatus according to an exemplary embodiment of the present invention, whether the air to be inspected is leaked by measuring a change in pressure and temperature in the test area 23 inside the jig 21 during the test time t. Determine. Specifically, the initial temperature T1 and the initial pressure P ₁ inside the jig 21 at the start of the air leakage test are measured, and the temperature (in the jig 21 after the predetermined test time t has elapsed) T ₂ ) and the pressure P ₂ are measured and the air leakage amount is calculated through the above-described equation (6) in the controller 42 using the value.

The air leak rate measurement unit 60 collects air leaking from the leaked portion of the inspected object and measures the leak of air leaked from the inspected object. Here, the time for collecting the air may be employed a variety of times to check the leakage site and to confirm the leakage amount. For example, when measuring the air leakage amount from the leaked portion through the air leakage measurement unit 60, a water submersion test may be employed, in this case, the air leakage measurement unit 60 is used to detect the air bubbles leaking from the test subject Can be captured through For reference, as the air leakage measuring unit 60, various devices for collecting air leaking from the inspected object may be all adopted.

The conversion unit 50 converts the air leakage measured by the air leakage measurement unit 60 into the cooling water leakage.

The coolant leakage amount may be calculated through Equation 7 below.

Equation 7

Here, Q _l is the coolant leakage amount, Q _a is the air leakage amount collected by the air leakage measurement unit 60, _a is the air viscosity, _l is the coolant viscosity, (P _i ) _l is the coolant test pressure, (P _i ) _a is the air test pressure.

Referring to FIG. 2, the coolant leak inspection apparatus according to another embodiment of the present invention is the same as the coolant leak leakage apparatus shown in FIG. 2 except for the configuration of the air cylinder 31.

The air cylinder 31 of the coolant leak inspection apparatus according to the second embodiment of the present invention, unlike the air cylinder 31 shown in the first embodiment, does not include the cooling fins 32 on the outer surface thereof, An element 36 is provided. In a closed circuit connected with two different types of metals, the thermoelectric element 36 generates a voltage difference between both ends of a conductor when heat is applied to one of the junctions. On the contrary, when a DC current is applied to both ends, the thermoelectric element 36 is absorbed at the junction according to the current direction. It uses the thermoelectric phenomenon which generates heat difference by heating. The thermoelectric element 36 may be operated by applying a predetermined power according to an external control switch. In this case, the thermoelectric element 36 is provided with a heat sink 37 having a sufficient size. In addition, the thermoelectric element 36 has a configuration in which a drive fan 38 is fixed to the heat sink 37.

According to the above configuration, when the temperature inside the air cylinder 31 rises above a predetermined temperature according to the surrounding environment, the inside of the air cylinder 31 by using the cooling function of the thermoelectric element 36 to correspond thereto. The temperature can be adjusted to an appropriate level. This enables accurate temperature control within a short time.

In other words, by utilizing the function of the thermoelectric element 36, the drive fan 38 is operated to bring the air flow inside the air cylinder 31 into contact with the heat sink 37, thereby providing the compressed air inside the air cylinder 31. The temperature can be adjusted to a temperature range suitable for differential pressure air leakage testing.

Hereinafter, a coolant leakage inspection method according to an exemplary embodiment of the present invention will be described in detail with reference to FIG. 3.

Referring to FIG. 3, first, the air is compressed using the compressor 11 (S10). At this time, the temperature of the air is higher than the initial temperature in the process of compressing the air using the compressor (11).

Next, the pressure of the air compressed by the compressor 11 using the regulator 12 is adjusted to the pressure necessary for the air leakage test (S20).

Then, the compressed air passed through the regulator 12 is injected into the air cylinder 31 (S30). The inside of the air cylinder 31 is then filled by the compressed air that has passed through the regulator 12. Therefore, as the compressed air is injected, the pressure inside the air cylinder 31 increases, and the pressure inside the air cylinder 31 is measured through the pressure sensor 35 to determine the pressure inside the air cylinder 31. It is determined whether the pressure is satisfied, that is, the pressure value required for the air leakage test (S40). As a result of the determination, if it is determined that the pressure inside the air cylinder 31 does not satisfy the predetermined pressure value, while the injection of compressed air into the air cylinder 31 is continued (S30), the inside of the air cylinder 31 The air pressure is measured again to determine whether or not the predetermined pressure value is satisfied (S40).

When it is determined that the pressure inside the air cylinder 31 satisfies a predetermined pressure value, here, the pressure value required for the air leakage test, the injection of compressed air into the air cylinder 31 is stopped, and the air cylinder 31 is stopped. The temperature inside is measured by the 1st temperature sensor 33, and it is determined whether the temperature inside the air cylinder 31 satisfies the range of predetermined temperature value, for example, the range of 0.1 of the outside temperature value (S50).

If it is determined that the temperature inside the air cylinder 31 does not satisfy the range of the predetermined temperature value, the temperature of the compressed air inside the air cylinder 31 is adjusted using the compressed air temperature controller (S60). do.

Adjusting the temperature of the compressed air inside the air cylinder 31 (S60), according to an embodiment of the present invention shown in Figure 1, the compressed air inside the air cylinder 31 is predetermined from the temperature of the outside air By standing until it reaches within the range, it can be made to adjust the temperature of the compressed air in the air cylinder 31 within a predetermined range. In this case, the temperature of compressed air can be adjusted simply without using a complicated temperature control apparatus. On the other hand, a plurality of cooling fins 32 are formed on the outer surface of the air cylinder 31 of the differential pressure type air leak device according to the present invention shown in FIG. 1, and the outside of the air cylinder 31 is caused by natural convection. The heat transfer is made easy.

In addition, adjusting the temperature of the compressed air inside the air cylinder 31 (S60) according to the embodiment of the present invention shown in Figure 2, the function of the thermoelectric element 36 installed inside the air cylinder 31 By using the air cylinder 31 may be made of a step of adjusting the temperature of the compressed air. On the other hand, according to a preferred embodiment of the present invention, the thermoelectric element 36 is provided with a heat sink 37 on one surface thereof, and further provided with a drive fan 38 that can be driven toward the heat sink 37, the air cylinder The compressed air inside the 31 can be made directly to the heat sink 37, so that the cooling efficiency can be further increased.

As in the embodiment of the present invention, when the thermoelectric element 36 is used, it is possible to precisely control the temperature within a short time as compared to the case where the temperature inside the air cylinder 31 is satisfied until the predetermined temperature range is satisfied. Has the advantage.

When it is determined that the temperature inside the air cylinder 31 satisfies the range of the predetermined temperature value, the valve 34 is opened to compress the compressed air stored in the air cylinder 31 to the jig 21 and the inspected object. Compressed air is injected into the inspection region 23 formed between the ends 22 (S70).

When compressed air is injected into the inspection region 23, the pressure inside the inspection region 23 is measured through the pressure sensor 41, so that the pressure inside the inspection region 23 is necessary for leak inspection, for example. It is determined whether or not the first pressure value has been reached (S80). If it is determined that the pressure inside the inspection region 23 has not reached the pressure value required for the leakage inspection, injection of compressed air (S70) is continued into the inspection region 23.

When it is determined that the pressure inside the inspection region 23 reaches the pressure value required for the leakage inspection, the leakage inspection is started to jig 21 to change the temperature change and the pressure variation inside the inspection region 23 for a predetermined time t. Measurement (S90) is performed using the third temperature sensor 24 and the pressure sensor 41 installed in the).

Next, the measured temperature value (T ₁ ) and pressure value (P ₁ ) at the start of the leak test and the temperature value (T ₂ ) and pressure value (P ₂ ) at the end of the leak test are expressed in the above equation (6). Substituting the controller 42 calculates an air leakage amount of the inspected object 22 (S100).

The control section 42 determines whether the air leakage amount calculated as a result of conversion by the conversion formula is equal to or greater than the set value (S110). In step 22, it is determined that leakage has occurred (S120).

Subsequently, the control unit 42 controls the air leakage measuring unit 60 to measure the air leakage amount leaking from the leaked portion of the object under test (S130).

When the air leakage amount is measured by controlling the air leakage amount measurement unit 60, the control unit 42 converts the air leakage amount to the coolant conversion amount using the above equation (6) (S140).

Subsequently, when the controller 42 leaks the coolant conversion amount, the controller 42 determines whether the total amount of coolant leaked by the preset amount is within the set time (S150). Here, the set amount and the set time are previously set values as the basis values which can be judged that the coolant leakage is serious when the set amount is leaked for the set time. For example, the set amount may be set to 1 cc, and the set time may be set to 30 minutes.

For reference, the dynamic viscosity of 25 air is 1.85X10 ^-5 Ns / m ² , the dynamic viscosity at the operating temperature of 90 ° C is about 10 cP (= 0.01Ns / m ² ), If 3.5 bar is generated inside the pump, the amount of cooling water converted to 0.046 cc / min is substituted by Equation 6 above.

In this case, assuming that the coolant is concentrated in a specific leakage part of the test object, it may be determined that 1cc is generated when the coolant operates under the same conditions for about 21.7 minutes.

That is, when leaking with the coolant conversion amount, the controller 42 determines that there is a coolant leakage when the total amount of leaked coolant water generated by the preset amount is within the set time (S160).

As described above, the present embodiment can estimate the leaked portion of the inspected object and the leaked amount of the coolant based on the leaked air of the inspected object.

In addition, the present embodiment can minimize the inspection area and minimize the temperature change of the compressed air during the inspection time, thereby reducing the air leakage deviation, thereby improving detection reliability and detection accuracy. In addition, by reducing the customer leakage of defective parts and errors that determine the regular goods as defective goods, it has the effect of minimizing the quality cost and reducing the cost.

Although the present invention has been described with reference to the embodiments shown in the drawings, it is merely exemplary and various modifications and equivalent other embodiments are possible to those skilled in the art. I will understand. Therefore, the true technical protection scope of the present invention will be defined by the claims below.

Claims

Injecting compressed air into a test region of the inspected object to determine whether air leaks from the inspected object by a change in pressure and temperature of the compressed air;

If it is determined that the air leaks from the inspected object, measuring the amount of air leaked from the inspected object; And

And converting the measured air leakage into coolant leakage.
The method of claim 1, wherein the determining of whether the air leaks from the inspected object is performed.

Storing compressed air such that the air pressure inside the air cylinder has a first pressure value;

Adjusting the temperature of the compressed air stored in the air cylinder to satisfy a first temperature value;

Injecting the compressed air stored in the air cylinder into an inspection region formed between a jig and a test object; And

And detecting the leakage of the inspected object by detecting a change in the pressure value and the temperature value of the compressed air in the inspection area.
The method of claim 2, wherein the determining of the leakage of the test object is performed.

Measuring a pressure value and a temperature value of the compressed air in the inspection area;

Measuring a change in pressure and temperature of the compressed air inside an inspection area;

Calculating an air leakage amount of the inspected object by using a change in pressure and temperature of the compressed air in the inspection region; And

And determining that leakage occurs in the inspected object when the calculated air leakage amount is equal to or larger than a set value.
The method of claim 1, further comprising the step of finally determining the coolant leakage based on the coolant leakage amount.
The method of claim 4, wherein the final determination of the coolant leakage based on the coolant leakage amount,

Coolant leakage test method characterized in that when the leakage of the coolant leakage amount of the coolant is determined as the leakage of the coolant if the time that the total amount of coolant occurs by a predetermined set amount is within a predetermined set time.