JPH09159566A - Leakage test method of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance detecting accuracy of a leakage test. SOLUTION: The whole openings except at least a single opening are masked among plural openings of respective passages of a water system and an oil system formed in this engine 10 which is in a semi-finish condition where at least a locker cover 38, a cylinder head 13, a cylinder block and an oil pan 20 are integrally installed through a gasket, and air is supplied in a fluid passage from this unmasked single opening, and the inside is pressurized, and a leakage of the engine in a semi-finish condition is detected on the basis of a pressure change in this fluid passage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine leak test method for detecting a leak in an intake passage, an exhaust passage, a cooling water passage, and an oil passage provided in an automobile engine.

[0002]

2. Description of the Related Art Generally, an automobile engine has a cylinder head and a rocker cover mounted on a cylinder block, and main motion system parts such as pistons, connecting rods, and crankshafts incorporated therein. An intake pipe and an exhaust pipe are attached to the outside. An intake port and an exhaust port that communicate with the combustion chamber are provided on both sides of the cylinder head, and an intake valve and an exhaust valve are provided at each port so that they can be opened and closed. Then, when the engine is driven, the intake valve and the exhaust valve move up and down to open and close the intake port and the exhaust port, thereby sucking the air-fuel mixture into the combustion chamber and discharging the combustion gas.

In such an automobile engine, a leak test is conducted after assembly and production in a factory. That is,
The engine is provided with air passages, oil passages, and cooling water passages for intake and exhaust over the cylinder head, cylinder block, etc.However, due to machining errors of each part, poor assembly accuracy, scratches during transportation, etc. There is a risk that a leak portion may occur on the oil passage or the cooling water passage. This leak test is for detecting a leak portion generated in each passage.

When performing the above-mentioned leak test of each passage, an opening portion of each passage, for example, an opening end portion of an intake pipe or an exhaust pipe connected to a cylinder head is mounted on an automobile engine in which each component is assembled. Is closed by a masking member, and air is supplied to the inside of the closed passage to apply pressure. Then, the leak is detected by detecting the internal pressure of the fluid passage and comparing it with a predetermined set pressure.

[0005]

However, as described above, the engine for performing the leak test is in a state in which the parts such as the intake pipe and the exhaust pipe are assembled on the outside of the engine body. A leak test is performed by blocking the air passage and oil passage formed by these accessory parts. Therefore, it is difficult to identify the detected leak location because there are many connection parts in the engine body and accessory parts. Therefore, it is possible to detect only large leaks due to lack of assembled parts,
It was difficult to detect minute leaks due to processing errors of each part, poor assembly accuracy, scratches, and the like. Particularly, it occurs in a cylinder block or the like during casting. If there is a porosity and there is a defect that oil oozes through this porosity, even if a leak is found in the engine after completion,
It is extremely difficult to find the cause because there are many leak factors.

The present invention is intended to solve such a problem, and an object of the present invention is to provide an engine leak test method for improving the detection accuracy of the leak test.

[0007]

According to the engine leak test method of the present invention for achieving the above object, at least the rocker cover, the cylinder head, the cylinder block, and the oil pan are interposed with each other through a gasket in the engine production process. A semi-finished engine that is assembled integrally into a single body by masking all the openings except at least one of the plurality of openings of the fluid passage formed in the engine. Air is supplied from one opening into the fluid passage to pressurize the inside of the fluid passage, and the leak of the engine in the semi-finished state is detected based on the pressure fluctuation in the fluid passage.

Therefore, the engine is in a semi-finished state in which the rocker cover, the cylinder head, the cylinder block, and the oil pan are integrally assembled with each other through the gasket. If all of the openings are masked except one and air is supplied from the unmasked openings to the inside of the fluid passage, the inside of the fluid passage is pressurized and maintained at a predetermined pressure. Due to the pressure fluctuations, engine leaks are detected.

[0009]

Embodiments of the present invention will be described below.

The engine leak test method of the present invention is
In a production process of an engine, a rocker cover, a cylinder head, a cylinder block, and an oil pan are integrally assembled with each other through a gasket to a semi-finished engine. That is, in the engine in this semi-finished state, for example, air passages, oil passages, and cooling water passages are formed as fluid passages by the above-mentioned components, and each passage is open to the outside with a plurality of openings. . Therefore, when performing the leak test, all the openings except at least one of the plurality of openings of each passage are closed by a masking member to seal each passage. Then, air is supplied into the respective passages from the openings of the respective passages that are not closed by the masking member to pressurize the inside. At this time, the pressure in each passage will be maintained at a predetermined pressure, but if there is a leak in a part of the passage, pressure fluctuation will occur in the passage, and based on this pressure fluctuation, engine leakage will occur. Is detected.

Further, in the engine leak test method of the present invention, main motion system parts such as pistons, connecting rods, and crankshafts are incorporated in the semi-finished engine, and a rocker cover, a cylinder head, and a cylinder block. , An oil pan and main motion system parts such as a piston, a connecting rod, and a crankshaft form an air passage, a cooling water passage, and an oil passage of a semi-finished engine. Therefore, all the openings except one of the plurality of openings formed in the engine are closed, and the air is supplied from the openings of the unopened paths to pressurize the inside. Then, the engine leak is detected based on the pressure fluctuation in each passage.

Further, in the engine leak test method of the present invention, among the plurality of openings of the air passage as the fluid passage formed in the semi-finished engine, the air passage communicates with the intake passage or the exhaust passage formed in the cylinder head. Air is supplied from the opening to detect the leak based on the pressure fluctuation in the air passage.

Further, in the engine leak test method of the present invention, a plurality of opening air of the oil passage as the fluid passage formed in the semi-finished engine is supplied, and the leakage is caused based on the pressure fluctuation in the oil passage. To be detected.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a front view of a leak test apparatus for carrying out an engine leak test method according to an embodiment of the present invention, and FIG. 2 is a side view of the leak test apparatus of the present embodiment.
3 is a front view of the left side masking device, FIG. 4 is a side view of the left side masking device, FIG. 5 is a front view of the upper masking device, FIG. 6 is a general engine outline, and FIG. 7 is a leak of the present embodiment. 1 shows a schematic of a semi-finished engine implementing a test method.

An engine corresponding to the leak test method of the present embodiment is, for example, a 4-cylinder DOHC engine.
That is, as shown in FIG. 6, in the engine 10, the cylinder head 13 is fixed on the cylinder block 11 via the cylinder gasket 12, and the piston 15 moves up and down in the cylinder 14 in the cylinder block 11. It fits freely. And cylinder block 1
A crankshaft 16 is rotatably supported on the lower part of the crankshaft 1, and a crankpin 17 is attached to the crankshaft 16 at a position eccentric from the center of the crankshaft 16. The lower end of a connecting rod 18 is connected to the crankpin 17. The upper end is connected to the piston 15. In addition,
A water jacket 19 communicated with the cylinder block 11 and the cylinder head 13 by a passage (not shown).
Is formed, and the oil pan 20 is fixed to the lower portion of the cylinder block 11.

Cylinder block 11 and cylinder head 1
3. The combustion chamber 21 is constituted by the piston 15, the intake port 22 and the exhaust port 23 are connected to the combustion chamber 21, and the intake valve 22 and the exhaust port 23 are provided with the tips of the intake valve 24 and the exhaust valve 25. Facing the combustion chamber 2
1 and each port 22, 23 can be opened and closed. Then, the intake pipe 2 is connected to the intake port 22.
6, exhaust pipes 27 are connected to the exhaust ports 23, respectively.

The cylinder head 13 is provided with a pair of intake camshafts 28 and exhaust camshafts 29 which are parallel to each other along the longitudinal direction thereof, and the intake cams each have a predetermined lift amount for each cylinder. 30 and exhaust cam 3
1 is integrally formed. The pair of cam shafts 28, 29 are respectively provided with a plurality of cam caps 32,
It is rotatably supported by 33. Further, the cylinder head 13 is provided with a pair of intake rocker shaft 34 and exhaust rocker shaft 35 which are parallel to each other along the longitudinal direction thereof.
Rocker arms 36 and 37 are attached to the vehicle 5. Each of the rocker arms 36 and 37 includes an intake cam 30 and an exhaust cam 3.
It drives by 1, and one end is in contact with the upper ends of the intake valve 24 and the exhaust valve 25. A rocker cover 38 is attached to the upper part of the cylinder head 13.

A fuel injection valve 39 for injecting fuel into the intake port 22 is mounted on the cylinder head 13, and the tip end thereof faces the combustion chamber 21 and the fuel introduced into the combustion chamber 21 A spark plug 40 for igniting an air-fuel mixture is attached with a cord cap for power distribution attached to its upper end.

Therefore, when the crankshaft 16 is rotationally driven, the piston 1 is moved through the connecting rod 18.
5 reciprocates in the cylinder 14. On the other hand, the camshafts 87, 29 synchronized with the drive of the crankshaft 16
Each cam 30, 31 is driven by the rotation of the rocker arm 3
At the same time when the intake valve 24 and the exhaust valve 25 are opened and closed via 6, 37, the fuel injection valve 39 injects high-pressure fuel into the intake port 22.
The steps of compression, explosion and exhaust are repeated. That is, when the intake valve 24 is opened, the intake port 22 is provided in the combustion chamber 21.
The air-fuel mixture is introduced into the air-fuel mixture from the spark plug 40, and the air-fuel mixture compressed by the rise of the piston 15 is ignited from the ignition plug 40 and exploded, and then the exhaust gas is exhausted from the exhaust port 23 when the exhaust valve 25 is opened.

The leak test method of this embodiment is performed in the semi-finished state of the engine 10 described above. As shown in FIG. 7, the semi-finished engine 10 includes a cylinder block 11, a cylinder head 13, and an oil pan 2.
No. 0, rocker cover 38, etc. are respectively assembled through a gasket, and main motion system parts such as piston 15, crankshaft 16, connecting rod 18, etc., each valve 24, 25, each camshaft 28, 29, etc. This is the engine body that incorporates the valve operating system components. That is,
Here, the engine body is the cylinder block 1 described above.
1, the cylinder head 13, the oil pan 20, and the rocker cover 38 are basic components that are assembled with each other, and additional components can be assembled from the outside without disassembling them into the basic components again. This allows the engine to be completed. Since the main motion system parts and the valve train system parts cannot be assembled from outside the engine body, they are installed inside before the engine body is assembled.

In the semi-finished engine 10, these components form an oil passage such as an air passage or an oil passage and a water passage such as a cooling water passage.
That is, on the upper surface of the engine 10 (the rocker cover 38, the cylinder head 13), there are four spark plug cap mounting holes (hereinafter referred to as plug holes) A communicating with the oil passage, and filler cap mounting holes (hereinafter referred to as plug holes). Hereinafter, referred to as an oil supply hole) B is formed. Also, the engine 10
A water pump mounting hole (hereinafter referred to as a pump hole) C communicating with the water passage is formed in the front surface of the (cylinder block 11). Further, on the rear surface portion of the engine 10 (rocker cover 38, cylinder head 13, cylinder block 11), a breather hole D communicating with the oil passage, two water outlet holes E communicating with the water passage, and an oil passage Is formed with a crankshaft oil hole (hereinafter, referred to as an oil supply crank hole) F.

Further, the engine 10 (cylinder head 1
3. On the left side surface of the cylinder block 11), there are an intake hole G and an oil level gauge insertion hole (hereinafter referred to as a level gauge hole) H communicating with the oil passage, and a water drain hole J communicating with the water passage. Has been formed. Furthermore,
Engine 10 (rocker cover 38, cylinder block 1
On the right side surface of 1), there is an exhaust hole K communicating with the oil passage.
And a PCV (positive crankcase ventilation) hole L and a water nipple hole M communicating with the water passage.
Are formed.

Here, the engine 1 in the semi-finished state described above
A leak test device corresponding to 0 will be described. FIG.
As shown in FIG. 2, in the leak test apparatus 40, the upper support base 41, the plurality of support columns 42, and the lower support base 4 are provided.
3, a gantry 44 is configured, and a gantry 44 is provided on the gantry 44 so that the gantry 44 can be conveyed from left to right in FIG. 1, stops at a predetermined work position, and reaches a predetermined height at this stop position. You can go up and do a leak test. On the other hand, the engine 10 described above is mounted on the pallet 46 in a state where at least the cylinder block 11, the cylinder head 13, the rocker cover 38, the oil pan 20, etc. are assembled.

In order to carry out a leak test of the engine 10, it is necessary to close the opening ends of the oil passage and the water passage to seal the inside, and the pedestal 44 is opened on the outer surface of the engine 10. A masking jig for closing the formed hole is provided. This masking jig is an upper masking jig 5 for closing each passage on the upper surface of the engine 10.
1, 52, a front masking jig 53 for closing each passage on the front surface of the engine 10, a rear masking jig 54 for closing each passage on the rear surface of the engine 10, and the engine 1
0, a left side masking jig 55 for closing each passage on the left side surface and a right side masking jig 56 for closing each passage on the right side surface of the engine 10. The upper masking jigs 51 and 52 close the plug hole A and the oil supply hole B of the engine 10, the front masking jig 53 closes the pump hole C of the engine 10, and the rear masking jig 5
4 can block the breather hole D, the water outlet hole E, and the crank hole F of the engine 10. Also,
The left side masking jig 55 closes the intake hole G, the level gauge hole H, the water inlet fitting hole I and the water drain hole J of the engine 10, and the right side masking jig 56 the exhaust hole K and PCV of the engine 10. The hole L and the water nipple hole M can be closed.

That is, a guide rail 61 is fixed to the above-mentioned pedestal 44, and a box-shaped lifting frame 62 is movably supported along the guide rail 61, and each masking jig 51 is supported on the lifting frame 62. , 52, 53,
54, 55, 56 are attached. Further, an elevating cylinder 63 is attached to the gantry 44, one end of a traction cable 65 is connected to a drive rod 64 that can be reciprocally driven upward, and the other end of the traction cable 65 is located above the gantry 44. It is connected to the upper part of the elevating frame 62 by being guided by the attached pulley 66. Therefore, when the elevating cylinder 63 is driven to extend or contract the drive rod 64, the elevating frame 62 is lowered or raised via the traction cable 65, whereby the masking jigs 51, 5
2, 53, 54, 55, 56 are the holes A of the engine 10
The L can be moved to the lowered position where it can be closed and the upper standby position.

The masking jigs 51, 5 described above are used.
Reference numerals 2, 53, 54, 55, and 56 denote the holes A to L of the engine 10 when the air cylinder is expanded and contracted at the above-described lowered position.
It has a similar structure.
Therefore, in the following description, the left side masking jig 55
Only the upper masking jig 51 will be described in detail. Further, the leak test apparatus 40 of the present embodiment can be applied to at least two types of engines, and two upper masking jigs 51 and 52 are used for holes in the upper surface of the engine. Correspondingly, each masking jig 5 for the holes in the front and rear surface parts and the left and right surface parts of the engine
This can be done by moving and adjusting the positions of 3, 54, 55 and 56.

In the left side masking jig 55, as shown in FIG.
As shown in FIG. 4, a pair of guide rails 72 are fixed along the vertical direction on the vertical board 71 fixed to the above-described lifting frame 62.
A moving plate 73 is movably supported on the unit 2. An air cylinder 74 is attached to the board 71,
The tip of the drive rod 75 extending downward is attached to the moving plate 73.
It is connected to. Further, a pair of support cylinders 76 are fixed to the moving plate 73, and a pair of support rods 78 fixed to the support plate 77 are inserted and fitted into the support cylinders 76, so that the support plate 77 extends in the horizontal direction. It is free to move. An air cylinder 79 is attached to the moving plate 73, and the tip of the horizontally extending drive rod 80 has a support plate 77.
It is connected to.

Four masking members 81 are attached to the support plate 77 corresponding to the intake holes G formed in the left side surface of the cylinder head 13 of the engine 10. The masking member 81 has a seal member 82 on the front surface, and can press the left side surface portion of the cylinder head 13 to close each intake hole G. Further, a masking member 83 is attached to the support plate 77 corresponding to the water inlet fitting hole I formed on the left side surface portion of the cylinder head 13. The masking member 83 has a seal member 84 on the front surface, and can press the left side surface portion of the cylinder head 13 to close the water inlet fitting hole I.

Further, a fixed plate 86 is attached to the base plate 71 by a connecting rod 85, an air cylinder 87 is attached to the fixed plate 86, and a cylinder block is provided at the tip of a horizontally extending drive rod 88. A masking member 89 is attached so as to correspond to the water drain hole J formed in the left side surface portion of 11. This masking member 8
The urethane rubber 9 is capable of being closed by fitting it into the water inlet fitting hole I. In addition, another substrate 90 fixed to the lifting frame 62
A fixed plate 92 is fixed to the fixed plate 92 by an L-shaped mounting bracket 91.
3 is rotatably attached. On the other hand, an air cylinder 95 is attached to the lower part of the fixed plate 92 by a mounting bracket 94.
Is installed. The tip end of the drive rod 96 of the air cylinder 95 is connected to the base end of the rotating piece 93, and the tip end is masked corresponding to the level gauge hole H formed on the left side surface of the cylinder block 11. Member 97
Is installed. The masking member 97 is made of urethane rubber and can be closed by being fitted in the level gauge hole H.

Therefore, when the drive rod 75 is expanded and contracted by the air cylinder 74, the moving plate 73 moves up and down, and the vertical positions of the masking members 81 and 83 mounted on the moving plate 73 via the support plate 77 and the like are set to the engine. It can be positioned according to the type of. And the air cylinder 7
When the drive rod 80 is extended by 9, the support plate 77 is guided by the support rod 78 and the support cylinder 76 to move forward,
The masking member 81 can press and close the intake holes G, and the masking member 83 can press and close the water inlet fitting hole I. Further, when the drive rod 88 is extended by the air cylinder 87,
The masking member 89 at the tip can be fitted into the water drain hole J to close it. Furthermore, the air cylinder 95
When the drive rod 96 is contracted by the rotating rod 93, the rotating piece 93 rotates counterclockwise in FIG. 4, and the masking member 97 at the tip end can be fitted into the level gauge hole H and closed.

In the upper masking jig 51,
As shown in FIG. 5, a pair of guide rails 101 are fixed to the elevating frame 62 along the horizontal direction, and a moving plate 103 is movably supported on the guide rails 101 by a guide member 102. Then, the lifting frame 62
An air cylinder 104 is attached to the moving plate 103, and the tip of a horizontally extending drive rod 105 is connected to the moving plate 103. An air cylinder 106 is attached to the moving plate 103, and an insertion rod 108 that is inserted into and removed from the cylinder head 13 through the rocker cover 38 is connected to the tip of the drive rod 107 that extends downward. There is. A masking member 109 is attached to the tip of the insertion rod 108 corresponding to the plug hole A formed in the upper surface of the cylinder head 13, and the masking member 89 is made of urethane rubber. It can be closed by fitting it into the plug hole A. Furthermore, the moving plate 103 has an air cylinder 1
10 is attached, and a masking member 112 is attached to the tip of the drive rod 111 extending downward corresponding to the oil supply hole B formed in the upper surface of the rocker cover 38.
This masking member 112 has a seal member 113 on the front surface,
The oil supply hole B can be closed by pressing the upper surface of the rocker cover 38.

Therefore, when the drive rod 105 is expanded and contracted by the air cylinder 104, the moving plate 103 moves in the horizontal direction,
The masking members 109 and 112 mounted on the moving plate 103
The left and right positions of the engine can be positioned according to the type of engine. Then, when the drive rod 107 is extended by the air cylinder 106, the masking member 109 at the tip of the insertion rod 108 can be fitted into the plug hole A and closed. Further, when the drive rod 111 is extended by the air cylinder 110, the masking member 112 at the tip end can be pressed against the oil supply hole B to close it.

The upper surface of the cylinder head 13 has 4
Although two plug holes A are formed, the masking member 10
Reference numeral 9 is for closing only one oil supply hole A adjacent to the oil supply hole B, and other plug holes A are closed by a masking member provided separately, but its operating mechanism is the masking member 109. The description is omitted because it is almost the same as.

The water-based passage and the oil-based passage in the engine 10 are closed and sealed by the masking members 51 to 56, and air can be supplied to the passages to pressurize them. ing. For example, in a water passage, as shown in FIG.
An air passage 121 is formed in the air passage 121. One end of the air passage 121 opens into the water inlet fitting hole I,
The other end is open to the outside and is connected to an air supply device (for example, an air pump) 122. Therefore, by supplying compressed air from the air supply device 122 through the water passage 121 to the water passage through the water inlet fitting hole I, the internal air pressure can be increased.

Further, for example, in an oil passage,
As shown in FIG. 5, an air passage 123 is formed in the masking member 112. One end of the air passage 123 is opened to the oil supply hole B, while the other end is opened to the outside to supply an air supply device (for example, an air pump). Etc.) are linked to 124. Therefore,
By supplying compressed air from the air supply device 124 through the air passage 123 to the inside of the oil system passage from the oil supply hole B, the internal air pressure can be increased. The air supplied from the oil supply hole B first enters the inside of the rocker cover 38 and the cylinder head 13, and then enters the cylinder block 11 and the oil pan 20 through a normal oil passage. Further, it enters the intake / exhaust ports 22, 23 through the gap between the intake / exhaust valves 24, 25, and further enters the combustion chamber 21.

Further, pressure detectors (not shown) for measuring the internal air pressure are provided in the water passage and the oil passage sealed by the masking members, respectively.
As shown in FIG. 1, each of the pressure detectors is connected to leak testers 131 and 132 provided so as to be connected to the mount 44. The leak testers 131 and 132 detect a leak in each passage by comparing the measured pressure in the water passage and the oil passage with a preset pressure.

The water inlet passage I is provided in the water passage for supplying air into the water passage and the oil passage in the engine 10, and the oil supply hole B is provided in the oil passage. However, in reality,
By supplying air from the intake hole G, the exhaust hole K, etc., the internal air pressure is promptly made uniform.

A leak test of the engine 10 by the leak test apparatus thus constructed will be described. As shown in FIGS. 1 and 2, the engine 10 has a rocker cover 38, a cylinder head 13, a cylinder block 11 and an oil pan 20 assembled therein and the piston 1 inside.
5, the crankshaft 16, the connecting rod 18, the valves 24 and 25, the camshafts 28 and 29, and the like, are placed on the pallet 46 in a semi-finished state and are conveyed by the conveyor 45. It is stopped at a predetermined position, and is raised by a predetermined height to be positioned at the working position. Then, the lifting cylinder 63 and the lifting frame 62 together with the masking jigs 51, 52, 53, 54,
55 and 56 descend and operate, and the respective holes of the water passage and the oil passage of the engine 10 are closed.

For example, on the left side surface of the engine 10, as shown in FIGS. 3 and 4, the masking jig 55 is used to introduce the intake hole G, the level gauge hole H, the water inlet fitting hole I, and the water of the engine 10. The drain holes J are closed. That is, by driving the air cylinder 79, each masking member 81 mounted on the support plate 77,
The masking member 81 closes each intake hole G and the masking member 83 closes the water inlet fitting hole I by advancing 83 and pressing against the left side surface of the engine 10. Further, by driving the air cylinder 87 to press the masking member 89 against the left side surface of the engine 10,
The masking member 89 closes the water inlet fitting hole I. Further, the air cylinder 95 is driven to rotate the rotating piece 93, and the masking member 97 is brought into pressure contact with the left side surface of the engine 10.
7 closes the level gauge hole H.

On the upper surface of the engine 10,
As shown in FIG. 5, the masking jig 51 closes the plug hole A and the oil supply hole B of the engine 10.
That is, the masking member 109 mounted on the insertion rod 108 is pressed against the upper surface of the engine 10 by driving the air cylinder 106, so that the masking member 109 is fitted into the plug hole A and closed. Further, the air cylinder 110 is driven to bring the masking member 112 into pressure contact with the upper surface of the engine 10, so that the masking member 112 closes the oil supply hole B.

The holes C, D, other than the holes A, B, G, H, I, J on the left side surface and the upper surface of the engine 10 described above.
Similarly for E, F, K, L and M, other masking jigs 5
It is closed by 3, 54 and 56.

Then, from the air supply device 122 to the air passage 121.
The internal pressure is set to a predetermined pressure by supplying compressed air into the water passage through the through. Then, the pressure detector measures the air pressure in the water passage, and the leak tester 131 compares the measured pressure in the water passage with a preset pressure to detect whether there is a leak. Also, the air supply device 12
By supplying compressed air from 4 to the oil passage through the air passage 123, the internal pressure is set to a predetermined pressure. Then, the pressure detector measures the air pressure in the water passage, and the leak tester 132 compares the measured pressure in the oil passage with a preset pressure to detect whether there is a leak.

[0044]

As described above in detail with reference to the embodiments, according to the engine leak test method of the present invention, at least the rocker cover, the cylinder head, the cylinder block and the oil pan are integrated with each other through the gasket. With respect to the assembled semi-finished engine, all the openings except at least one of the plurality of openings of the fluid passage formed in the engine are masked, and the fluid is discharged from the unmasked opening. Air is supplied to the passage to pressurize the inside, and the leak of the semi-completed engine is detected based on the pressure fluctuation in the fluid passage, so minute leaks at the joints of each part can be easily and Therefore, it is possible to surely detect, and it is possible to improve the detection accuracy of the leak test. In particular, it is possible to reliably deal with a leak due to a porosity or the like of a cylinder block or the like.

According to the engine leak test method of the present invention, the engine in a semi-finished state has the main motion system parts such as the piston, connecting rod and crankshaft incorporated therein, and is formed in this engine. Since the air is supplied from the openings communicating with the upper and lower sides of the piston to pressurize the inside of the multiple openings of the fluid passage, the air pressure is applied to both the upper and lower sides of the piston to create a balanced state. Since there is no pressure fluctuation due to air leakage between the cylinder and the cylinder peripheral wall, and there is no erroneous detection of leak due to this pressure fluctuation, the leak in the fluid passage can be reliably detected.

Further, according to the engine leak test method of the present invention, among the plurality of openings of the fluid passage formed in the semi-finished engine, the opening communicating with the intake passage or the exhaust passage formed in the cylinder head. Since the air is supplied from above to pressurize the inside, a minute leak in the fluid passage communicating with the intake passage or the exhaust passage can be easily and reliably detected.

Further, according to the engine leak test method of the present invention, air is supplied from the opening of the oil filler cap formed in the rocker cover among the plurality of openings of the fluid passage formed in the semi-finished engine. Since the inside is pressurized, the minute leak in the fluid passage communicating with the opening of the oil filler cap can be easily and surely detected.

[Brief description of the drawings]

FIG. 1 is a front view of a leak test apparatus for carrying out an engine leak test method according to an embodiment of the present invention.

FIG. 2 is a side view of the leak test apparatus of this embodiment.

FIG. 3 is a front view of a left side masking device.

FIG. 4 is a side view of a left side masking device.

FIG. 5 is a front view of an upper masking device.

FIG. 6 is a schematic diagram of a general engine.

FIG. 7 is a schematic diagram of an engine in a semi-finished state in which the leak test method of the present embodiment is implemented.

[Explanation of symbols]

 10 Engine 11 Cylinder Block 13 Cylinder Head 20 Oil Pan 38 Rocker Cover 40 Leak Test Device 44 Frame 51-56 Masking Jig 62 Elevating Frame 63 Elevating Cylinder 121,123 Air Passage 122,124 Air Supply Device 131,132 Leak Tester

Claims (4)

[Claims] 1. A semi-finished engine in which at least a rocker cover, a cylinder head, a cylinder block, and an oil pan are integrally assembled with each other through a gasket in an engine production process. All the openings except at least one of the plurality of openings of the fluid passage are masked, and air is supplied into the fluid passage from the unmasked opening to pressurize the inside of the fluid passage. A leak test method for an engine, comprising: detecting a leak of the semi-finished engine based on a pressure fluctuation in the engine. 2. The engine leak test method according to claim 1, wherein the semi-finished engine has main motion system parts such as a piston, a connecting rod and a crankshaft incorporated therein, and is formed in the engine. A leak test method for an engine, wherein air is supplied from the openings communicating with the upper and lower sides of the piston to pressurize the inside of the plurality of openings of the fluid passage. 3. The engine leak test method according to claim 1, wherein among the plurality of openings of the fluid passage formed in the semi-finished engine, an intake passage or an exhaust passage formed in the cylinder head. A method for leak testing an engine, characterized in that air is supplied from an opening communicating with the engine to pressurize the inside. 4. The engine leak test method according to claim 2, wherein, out of a plurality of openings of a fluid passage formed in the semi-finished engine, an air is discharged from an opening of an oil filler cap formed in the rocker cover. A leak test method for an engine, characterized in that the inside is pressurized to supply the inside.