JP2005201080A - Cylinder head cover - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder head cover capable of facilitating maintenance and exchange of a relief valve. <P>SOLUTION: At an ordinary time, after blow-by gas in a top face chamber 2a of a cylinder head separates oil by a first filter 8 over a main gas flow path, it is discharged to the suction side. Meanwhile, when an internal pressure in a cylinder head top face chamber 2a is increased to a value higher than a given value, a relief valve 12 integrated in an oil filer cap 11 is automatically opened to open a bypass flow channel, and blow-by gas is discharged to the suction side through the bypass flow channel. Further, by removing an oil filler cap 11 from a cover body 4, maintenance of the relief valve and its exchange during the occurrence of trouble are executed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cylinder head cover fixed to a cylinder head of an internal combustion engine.

  For example, Patent Document 1 discloses a cylinder head cover in which an oil separation case for separating oil in blow-by gas is formed. A porous filter is arranged in the oil separation case of the cylinder head cover, and blow-by gas in the cylinder head upper surface chamber is discharged from the discharge port to the intake manifold through the filter. The oil separation case is also provided with a relief valve that opens when the internal pressure of the cylinder head upper surface chamber rises to a predetermined value or more and communicates the gas flow path downstream of the porous filter and the cylinder head upper chamber. Thus, the internal pressure of the cylinder head upper surface chamber is prevented from abnormally increasing due to clogging of the filter.

Japanese Utility Model Publication No. 60-143122

However, in the above-described cylinder head cover, the relief valve is formed integrally with the case frame that forms the oil separation case. Therefore, when the relief valve is maintained or replaced, the cylinder head cover is removed after the cylinder head cover is removed. There is a problem that it is necessary to remove the entire case frame from the cylinder head cover.
The present invention has been made to solve such problems, and an object of the present invention is to provide a cylinder head cover that can easily perform maintenance and replacement of a relief valve.

  A cylinder head cover according to the present invention is a cylinder head cover that separates oil and discharges it to an intake side by passing blow-by gas in a cylinder head upper surface chamber through a first filter disposed on a main gas flow path in the cover body. A bypass channel formed in the cover body so as to bypass the first filter and communicate the cylinder head upper surface chamber and the intake side, and is detachably attached to the cover body to block the bypass channel. An oil filler cap and a relief valve that is disposed in the oil filler cap and that automatically opens when the internal pressure of the cylinder head upper surface chamber rises to a predetermined value or more and opens the bypass flow path are provided.

  Normally, blow-by gas in the cylinder head upper surface chamber is discharged to the intake side after the oil is separated by the first filter on the main gas flow path. On the other hand, when the internal pressure of the cylinder head upper surface chamber rises to a predetermined value or more due to clogging of the first filter or the like, the relief valve built in the oil filler cap automatically opens and the bypass flow path is opened. Thereby, blow-by gas in the cylinder head upper surface chamber is discharged to the intake side through the bypass flow path. Also, by removing the oil filler cap from the cover body, the relief valve is maintained and replaced in the event of a failure.

If the cover main body is formed so that the main gas flow path and the bypass flow path have a common discharge port for discharging blow-by gas to the intake side, the structure of the entire cylinder head cover is simplified.
Further, it is preferable that a second filter is disposed on the downstream side of the oil filler cap in the bypass flow path, and the blowby gas that has passed through the relief valve is discharged to the intake side through the second filter. In this case, you may comprise so that the blow-by gas which flows through a main gas flow path may also be discharged | emitted to the intake side through a 2nd filter after passing a 1st filter. In this way, the blow-by gas is discharged to the intake side after passing through the second filter, so that foreign matters are not mixed into the intake side.

  According to the present invention, the bypass passage formed in the cover body so as to bypass the first filter and communicate the cylinder head upper surface chamber and the intake side, and is detachably attached to the cover body. An oil filler cap that shuts off the bypass flow path, and a relief valve that is disposed inside the oil filler cap and that automatically opens when the internal pressure of the cylinder head upper surface chamber rises to a predetermined value or more and opens the bypass flow path. Therefore, the relief valve can be easily maintained and replaced.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows the overall configuration of a cylinder head cover according to an embodiment of the present invention. The cylinder head cover 1 is fixed to the upper part of the cylinder head 2 of the internal combustion engine via an oil seal member 3 and covers the cylinder head upper surface chamber 2a. In the cylinder head upper surface chamber 2a, a valve operating mechanism including a cam shaft for operating an intake valve and an exhaust valve is accommodated. The cylinder head cover 1 has a cover body 4, and an oil separation case 5 and a bypass case 6 are defined in both ends of the cover body 4. The oil separation case 4 and the bypass case 6 A discharge case 7 is defined between the two.

  A first filter 8 made of a porous filter is arranged in the oil separation case 5, and a second filter 9 made of a porous filter having a coarser mesh than the first filter 8 is arranged in the discharge case 7. ing. A gas discharge port 10 connected to an intake manifold (not shown) is formed on the upper wall surface of the discharge case 7. The oil separation case 5 and the bypass case 6 respectively have gas inlets 5a and 6a that communicate with the discharge case 7 and open to the cylinder head upper surface chamber 2a. In the cover body 4, there are a main gas passage extending from the gas inlet 5 a to the gas outlet 10 through the first filter 8 of the oil separation case 5 and the second filter 9 of the outlet case 7, and the gas inlet A bypass passage is formed from 6a to the inside of the bypass case 6 and the gas exhaust port 10 through the second filter 9 of the discharge case 7.

In addition, an oil filler cap 11 is detachably attached to the cover body 4, and the gas inlet 6a of the bypass case 6 is normally closed by the tip of the cap 11, that is, the oil filler cap. 11 bypasses the bypass channel.
The oil filler cap 11 has a relief valve 12 inside. The relief valve 12 has a relief flow path 12a formed so as to escape from the front end portion of the oil filler cap 11 to the side portion, and automatically opens when the internal pressure of the cylinder head upper surface chamber 2a rises to a predetermined value or more. The relief channel 12a is set to open. The relief flow path 12a is located on the bypass flow path. Therefore, when the relief valve 12 is opened and the relief flow path 12a is opened, the bypass flow path is also opened.

The oil filler cap 11 is attached by screwing to the cover body 4. However, when the cap 11 is attached to the cover body 4, the bypass case 6 spreads on the outer periphery of the front end portion of the cap 11. 11, the outlet of the relief channel 12 a is configured to communicate with the inside of the bypass case 6 in any direction in the bypass case 6.
Further, O-rings 13 and 14 that are seal members are provided between the front end portion of the oil filler cap 11 and the lower wall surface of the bypass case 6 and between the base end portion of the oil filler cap 11 and the upper surface of the cover body 4, respectively. Is arranged.
In addition, the gas inlet 6a of the bypass case 6 also serves as a gas inlet of the bypass flow path as an oil inlet for injecting lubricating oil into the cylinder head upper surface chamber 2a.

  Next, the operation of the cylinder head cover 1 having the above configuration will be described. In normal times, the blow-by gas in the cylinder head upper surface chamber 2a is discharged to the intake side through the main gas flow path as indicated by the solid line arrow in FIG. That is, blow-by gas flows into the oil separation case 5 from the gas inlet 5a, and after the oil is separated by the first filter 8, it passes through the second filter 9 of the discharge case 7 from the gas discharge port 10. It is discharged to the intake manifold. An oil discharge port 5b is formed in the lower wall surface of the oil separation case 5, and the oil separated from the blow-by gas by the first filter 8 is discharged from the oil discharge port 5b into the cylinder head upper surface chamber 2a. Is done.

  Further, when the first filter 8 is clogged due to sludge generated by the reaction between the additive contained in the oil in the blow-by gas and the moisture in the blow-by gas, the internal pressure of the cylinder head upper surface chamber 2a is increased. When the internal pressure of the cylinder head upper surface chamber 2a rises to a predetermined value or more, the relief valve 12 built in the oil filler cap 11 is automatically opened to open the bypass flow path. As shown, the blow-by gas in the cylinder head upper surface chamber 2a flows into the bypass case 6 from the gas inlet 6a through the relief flow path 12a, and further passes through the second filter 9 of the discharge case 7 to exhaust the gas. It is discharged from the outlet 10 to the intake manifold. Accordingly, the internal pressure of the cylinder head upper surface chamber 2a is prevented from rising abnormally, and as a result, problems such as oil leaking from the boundary between the cylinder head cover 1 and the cylinder head 2 are prevented.

  Here, since the relief valve 12 is provided in the oil filler cap 11, and this cap 11 is detachable with respect to the cover main body 4, when the relief valve 12 breaks down, the cylinder head cover 1 is attached to the cylinder head. The relief valve can be easily replaced by simply removing the oil filler cap 11 from the cover body 4 and replacing the cap 11 with a new one without removing it from the cover body 4. Accordingly, the relief valve can be easily maintained and assembled. In addition, since only the oil cap 11 needs to be replaced when the relief valve fails, the cost can be kept low.

Since the relief valve 12 is provided in the oil filler cap 11, the oil inlet of the oil filler cap 11 can be used as the gas inlet 6a of the bypass case 6, that is, the gas inlet of the bypass channel. The structure could be simplified.
The blow-by gas that has passed through the relief flow path 12a of the relief valve 12 passes through the second filter 9 of the discharge case 7 and is discharged from the gas discharge port 10 to the intake manifold. It is possible to prevent foreign matters from being mixed in.

It is sectional drawing which shows the cylinder head cover which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Cylinder head cover, 2 Cylinder head, 2a Cylinder head upper surface chamber, 3 Oil seal member, 4 Cover main body, 5 Oil separation case, 5a, 6a Gas inlet, 5b Oil exhaust port, 6 Bypass case, 7 Discharge case, 8 1 filter, 9 second filter, 10 gas outlet, 11 oil filler cap, 12 relief valve, 12a relief flow path, 13, 14 O-ring.

Claims (4)

In the cylinder head cover that separates and discharges oil to the intake side by passing blowby gas in the cylinder head upper surface chamber through the first filter disposed on the main gas flow path in the cover body,
A bypass flow path formed in the cover body so as to bypass the first filter and communicate the cylinder head upper surface chamber and the intake side;
An oil filler cap that is detachably attached to the cover body and blocks the bypass flow path;
A cylinder head cover, comprising: a relief valve disposed in the oil filler cap and automatically opened when the internal pressure of the cylinder head upper surface chamber rises to a predetermined value or more to open the bypass passage.   2. The cylinder head cover according to claim 1, wherein the cover main body has a common outlet for the main gas flow path for discharging blow-by gas to the intake side and the bypass flow path.   The second filter is disposed downstream of the oil filler cap in the bypass flow path, and blow-by gas that has passed through the relief valve is discharged to the intake side through the second filter. Item 3. The cylinder head cover according to Item 1 or 2.   4. The cylinder head cover according to claim 3, wherein the blow-by gas flowing through the main gas flow path is also discharged to the intake side through the second filter after passing through the first filter.

Images