JPH1123405A - Leakage testing method for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a leak testing method for an engine which enables detection of presence/absence of a leakage of an upright intake port joint plane quickly and easily without considering the endurance of a seal. SOLUTION: In the production of an internal cylinder injection gasoline engine in which an upright intake port pierces both of a cylinder head 1 and a cam shaft body joined on the cylinder head 1 to communicate with a combustion chamber, at the stage of mutual joint of the cylinder head 1 and the cam shaft body 2, each part communicating with the outside of the cylinder head 1 and the cam shaft body 2 penetrated by the upright intake port are masked by an injector surface masking member 20, a lower masking member 21, an upper masking member 22 and a side masking member 23 while compressed air is supplied from one location of these masked parts. At the same time, changes in the pressure of the compressed air are checked to detect a leak from the upright intake port joint plane between the cylinder head 1 and the cam shaft body 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak test method for inspecting the airtightness of an upright intake port mating surface in an automobile engine.

[0002]

2. Description of the Related Art In recent years, in a gasoline engine, as in the case of a diesel engine, a direct injection gasoline engine that directly injects fuel into a cylinder has been realized. In such a direct injection gasoline engine, the fuel injection timing can be largely changed according to the operating state of the engine, and the exhaust gas can be reduced while improving the performance of the engine.

[0003] In the cylinder head of such a direct injection gasoline engine, an upright intake port is adopted from the viewpoint of easy flame propagation, thermal load on the injector, ease of layout, intake efficiency, and the like. It is also well known. This upright intake port allows the flow entering the cylinder from the port to create a tumble flow in the opposite direction to that of a conventional engine, and is injected into a small piston cavity, which is also new to the engine. A flow suitable for transporting the fuel to the spark plug is obtained.

[0006] As shown in FIG. 6, in the above-described in-cylinder injection gasoline engine, the cylinder head 10
0 and the rocker cover 101 mounted on the upper surface of the cylinder head 100, the above-described upright intake port 102 is formed. In the figure, 103 is an exhaust port,
It communicates with the combustion chamber 104 together with the upright intake port 102. Reference numeral 105 denotes an intake valve for opening and closing the upright intake port 102 by the valve operating mechanism 106, and reference numeral 107 denotes the valve operating mechanism 10
An exhaust valve 8 opens and closes the exhaust port 103.

Therefore, the cylinder head 10 at the factory
After assembling the locker cover 101 with the
A leak test is performed on the mating surface A of the upright intake port 102 between 0 and 101.

As described in Japanese Patent Application No. 7-317681 filed by the present applicant, this leak test is for preventing the lubricating oil inside a cylinder head or the like from entering the intake passage and hindering combustion. In this application, as shown in FIG.
A balloon-type seal 110 made of a soft material is inserted into the inside 02, and air is supplied through an air supply pipe 112 to the space formed between the balloon-type seal 110 and the upper surface seal 111 pressed against the upper surface of the rocker cover 101, and pressurized. Then, the leak (leakage) at the mating surface A is detected by detecting the internal pressure of this space and comparing it with a predetermined set pressure.

[0007]

In the above-mentioned conventional leak test method, since the balloon type seal 110 made of a soft material is used, the handling is troublesome and it takes time for the test. Since the contact surface of 110 (the inner wall surface of the upright intake port 102) has a casting surface, there is a problem in the durability of the seal, which is not suitable for mass production equipment. For this reason, the inventor of the present application has set the intake port 10
It was considered that the opening of the combustion chamber 2 was closed, but it was difficult to seal the opening due to its complicated shape. Further, after the intake valve 105 was assembled, the intake valve 105 was in the way and could not be closed. There was an inconvenience of becoming.

SUMMARY OF THE INVENTION An object of the present invention is to provide a leak test method for an engine that can quickly and easily detect the presence or absence of a leak at a mating surface of an upright intake port without considering the durability of the seal. is there.

[0009]

According to a first aspect of the present invention, there is provided a leak test method for an engine, comprising: a cylinder head having an intake port and a camshaft body joined to the cylinder head; In manufacturing an engine that communicates with the combustion chamber through both of the cylinder head and the camshaft body, at the stage where the cylinder head and the camshaft body are joined to each other, a portion where the intake port communicates with the outside of the cylinder head and the camshaft body is described. Masking from the outside, supplying compressed fluid from one of these masked portions, and detecting pressure fluctuation of the fluid to detect a leak at the joint surface between the cylinder head and the camshaft body. It is characterized by the following. According to this, it is possible to quickly and easily detect the presence / absence of a leak at the mating surface of the upright intake port without considering the durability of the seal. In addition, since the test can be performed with the intake and exhaust valves incorporated, there is an advantage that it is not necessary to disassemble the cylinder head and the camshaft body again after the test.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an engine leak test method according to the present invention will be described in detail using embodiments with reference to the drawings.

FIG. 1 is a system configuration diagram showing one embodiment of an engine leak test method according to the present invention. FIGS. 2 and 3 are diagrams of an engine to which an engine leak test method according to the present invention is applied. FIG. 4 is a sectional view of a cylinder head portion, FIG. 4 is a bottom view of the cylinder head, and FIG. 5 is a plan view of a camshaft body.

First, in the engine leak test method according to the present invention, an intake port penetrates both a cylinder head and a camshaft body (also referred to as an integral cam cap) joined on the cylinder head to a combustion chamber. Applies to communicating engines.

That is, as shown in FIG. 2, a camshaft body 2 (not shown) is provided on the upper surface of a cylinder head 1 on the left bank side of a V-type 6-cylinder DOHC gasoline engine having three cylinders on one bank side. Upright intake ports 4 tightly joined via gaskets and communicating with the respective combustion chambers 3 formed in the cylinder head 1 are formed by vertically penetrating the two members 1 and 2 for two per combustion chamber 3. Is done.

On the upper surface of the camshaft body 2, each branch pipe 5 of the intake manifold is joined via a seal member 6 to communicate with each of the upright intake ports 4. A pair of left and right rocker covers 8 are joined through the intermediary.

The cylinder head 1 is formed with two exhaust ports 9 communicating with each combustion chamber 3 (only one exhaust port 9 is shown per combustion chamber 3) and is joined to the side surface of the cylinder head 1. It is connected to each branch pipe of the exhaust manifold (not shown).

Each of the upright intake ports 4 is opened and closed by an intake valve 10 through a valve operating mechanism 11, and the exhaust port 9 is opened and closed by an exhaust valve 12.
3 for opening and closing.

The camshaft body 2 is supported by bolts 14 to support the camshafts 11a and 13a of the valve mechanisms 11 and 13 in cooperation with a semicircular bearing (not shown) on the upper surface of the cylinder head 1. A plurality of cam caps 15 arranged in a plurality of rows in the cylinder row direction are integrally formed with a frame-shaped plate (beam member) 16 by casting. And this camshaft body 2
It is manufactured as an integral part of the cylinder head 1 and is provided for transportation.

The engine leak test according to the present invention is performed by the cylinder head 1 and the camshaft body 2.
Are performed at a stage where they are mutually joined via a liquid gasket in a state where the valve train components shown in FIG. 2 are assembled. In this state, the portion that communicates with the joint surface A, which is the leak confirmation portion, and communicates with the outside is the upper end a of the intake port of the camshaft body 2, the upper end b of the spark plug mounting hole 17 formed on the same surface as the upper end a, There are five locations: the lower surface c of the combustion chamber 3 in the cylinder head 1, the end d on the exhaust port side, and the opening e of the injector mounting hole 18. These are all other parts (above and the intake manifold,
Is a portion to which a cylinder block, an exhaust manifold, and an injector are attached, and its surface is smoothly cut. An intake manifold having a hole communicating with the hole 17 is fixed to the upper end b of the ignition plug mounting hole 17, and an ignition coil is hermetically fixed to the hole. In addition, each valve 10.1
Since the gap between the pipe 2 and the surrounding guide pipe 19 is very small, there is almost no leakage.

That is, as shown in FIG. 1, the cylinder head 1 and the camshaft body 2 which have been conveyed to the leak test device by a conveyor (not shown) are firstly moved by a swingable injector surface masking member 20. Each injector mounting hole 1 opening on the side surface of the cylinder head 1
8 is closed.

Next, each of the combustion chambers 3 and the like, which are opened on the lower surface of the cylinder head 1, is closed by a vertically movable lower surface masking member 21 having a pressurizing port 21a, and the cylinder head 1 and the camshaft body are kept in this state. 2 is lifted up to a predetermined position (see the state of FIG. 1).

Next, each of the upright intake ports 4 and the spark plug mounting holes 17 opened on the upper surface of the camshaft body 2 by a vertically movable upper surface masking member 22 having a pressurizing port 22a.
Etc. are closed.

Finally, each of the exhaust ports 9 and the like which are opened on the side surface of the cylinder head 1 are closed by a horizontally movable side masking member 23 having a pressurizing port 23a.

As a result, all the spaces of the cylinder head 1 and the camshaft body 2 including the upright intake port 4 are sealed.

The injector surface masking member 2
0, lower surface masking member 21, upper surface masking member 22
The side masking member 23 is appropriately supported on a single gantry 24 as a leak test device via a support base and a support column, and performs the above-described required operation via a guide member as appropriate by expansion and contraction of an air cylinder or the like. It has become.

After the above-mentioned sealing, one of the pressure openings 21a, 22a, 23a of the lower surface masking member 21, the upper surface masking member 22, and the side surface masking member 23 is used, for example, as shown in FIG. The compressed air is supplied from the compressed air supply device 25 to the space of the cylinder head 1 and the camshaft body 2 including the upright intake port 4 through the leak tester 26, which is an air flow tester, to the predetermined pressure. Press.

When the predetermined pressure is reached, the air supply is stopped,
Thereafter, a leak tester compares the pressure with a set pressure or the like to detect whether or not there is a leak at the upright intake port mating surface A (see FIG. 2) between the cylinder head 1 and the camshaft body 2.

Each of the above masking members has a relatively thick rubber or the like at its joint surface with the engine, which is much more durable than a conventional balloon made of a thin rubber or the like, and which allows smooth cutting. Since the processing surface is pressed, the durability is further improved and the sealing property is also good.

Further, since the leak test can be performed with the valve train components shown in FIG. 2 assembled, extra work such as disassembling the cylinder head and the camshaft body again after the leak test and assembling the valve train components is performed. Does not require Therefore, this test method has an advantage that the leak test process can be easily incorporated in the middle of the production line without disturbing the engine production order. In addition, this method has no problem even if the test is performed with the spark plug or the injector attached. in this case,
The masking member 20 is unnecessary, and the member 22 does not need to close the spark plug mounting hole 17. Further, the injector surface masking member 20, the lower surface masking member 2
1, top masking member 22 and side masking member 2
Since each of the operations 3 is also a simple operation, automation is easy. That is, in the method of the present invention, when checking for the presence or absence of a leak at the joint surface between the cylinder head and the camshaft body at the intake port, the method communicates with the intake port instead of directly closing the intake port before or after the joint surface or the intake port itself. The test is performed by closing each opening to the outside. According to this, the test can be performed irrespective of the shape of the intake port or the combustion chamber, or the presence or absence of the internal components. Of course, the test can be performed regardless of the open / close state of the intake and exhaust valves 10 and 12.

As described above, the present invention is applied to an engine in which the intake port extends through both the cylinder head and the camshaft body. Therefore, gasoline is directly injected into the combustion chamber. It is suitable for use in a direct injection gasoline engine that causes an ignition explosion. In addition, the camshaft body in the present invention refers to a camshaft body that includes a valve train component inside and has an intake port that is joined to the cylinder head and communicates with the cylinder head, regardless of its name. Needless to say, it also includes the rocker cover shown in FIG.

The present invention is not limited to the above embodiment,
It goes without saying that various changes can be made without departing from the spirit of the present invention.

[0031]

As described above, according to the first aspect of the present invention, an engine is manufactured in which the intake port penetrates both the cylinder head and the camshaft body joined to the cylinder head to communicate with the combustion chamber. In doing so, at the stage where the cylinder head and the camshaft body are joined to each other, the portion where the intake port communicates with the outside of the cylinder head and the camshaft body is masked from the outside, and among the masking portions, By supplying the compressed fluid from one place and detecting the pressure fluctuation of the fluid, the leak at the joint surface between the cylinder head and the camshaft body is detected, so that the leakage can be quickly performed without considering the durability of the seal. In addition, the presence or absence of a leak can be easily detected.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing an embodiment of an engine leak test method according to the present invention.

FIG. 2 is a sectional view of a cylinder head portion of an engine to which an engine leak test method according to the present invention is applied.

FIG. 3 is a cross-sectional view of different portions of a cylinder head of an engine to which an engine leak test method according to the present invention is applied.

FIG. 4 is a bottom view of the cylinder head of the engine to which the engine leak test method according to the present invention is applied.

FIG. 5 is a plan view of a cylinder head portion of the engine to which the engine leak test method according to the present invention is applied.

FIG. 6 is a sectional view of a cylinder head portion of an engine showing a conventional leak test method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Camshaft body 3 Combustion chamber 4 Upright intake port 9 Exhaust port 20 Injector surface masking member 21 Lower surface masking member 22 Upper surface masking member 23 Side masking member A Upright intake port mating surface

Claims (1)

[Claims] When manufacturing an engine in which an intake port penetrates both a cylinder head and a camshaft body joined to the cylinder head to communicate with a combustion chamber, the cylinder head and the camshaft body are interconnected. At this stage, the portion where the intake port communicates with the outside of each of the cylinder head and the camshaft body is masked from each outside, and the compressed fluid is supplied from one of the masked portions and the pressure of the fluid is increased. A leak test method for an engine, wherein a leak at a joint surface between the cylinder head and the camshaft body is detected by detecting a fluctuation.