JP2002357124A - Cooling water piping structure of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a local bending part 22 of piping extending from a radiator 4 to an engine body 1 from becoming an obstacle against air bleeding when pouring water. SOLUTION: A cooling water system consists of the engine body 1, the radiator 4, an upper part cooling water passage 12, and a lower part cooling water passage 10. Water is poured through a water filling port 6 in an upper part of the radiator 4 when pouring water, and cooling water flows into the engine body 1 through the upper part cooling water passage 12. The upper part cooling water passage 12 is provided with the bending part 22 bent downward to avoid the interference with other parts, and air bleeding pipings 31 are arranged in parallel to connect its both side parts mutually. Even if cooling water is collected in the bending part 22 when pouring water, it is possible to bleed air from the engine body 1 side through the air bleeding piping 31 to avoid remaining of air.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling water piping structure for an automobile engine or the like, and more particularly to a cooling water piping structure in which air is taken out when cooling water is injected.

[0002]

2. Description of the Related Art If air is mixed in a cooling water system including a water jacket, a radiator, and a cooling water pipe between them in an engine body, an intended cooling performance cannot be maintained, so that cooling water cannot be maintained. It is necessary to prevent air from remaining inside the cooling water system during water injection work.

A water injection port for water injection is generally provided, for example, in the upper part of a radiator or in the middle of a cooling water pipe near a radiator which is the uppermost part of a cooling water system. If not provided, the air in the system must be discharged from the water injection port when water is injected into the system.

Therefore, for example, Japanese Patent Application Laid-Open No.
As disclosed in Japanese Patent Application Laid-Open Publication No. H10-163, there is also known a configuration in which a thin air vent passage is provided from an upper portion of a water jacket where air tends to remain to a position of a radiator cap serving as a water inlet.

[0005]

In recent years, the density of various components in an engine room of an automobile has been increasing more and more, and the degree of freedom of the layout of cooling water piping tends to be restricted accordingly. Therefore, for example, in order to avoid interference with some parts, the cooling water pipe from the water inlet to the engine body may be locally bent downward in a U-shape on the way. In such a case, when water is injected from the water inlet on the radiator side, the cooling water pipe becomes locally blocked when the cooling water accumulates in the bent portion, and the downstream side, that is, the engine body side A large amount of air may remain.

Further, in the configuration in which the air vent passage is provided from the engine body to the position of the radiator cap as in the above-described conventional case, the air vent passage becomes very long, and the piping layout becomes difficult. For example, there is a place that hangs down in the middle of this air vent passage, and if cooling water accumulates here, smooth air bleeding cannot be performed, so basically from the engine body side to the radiator cap side It is necessary to configure the air vent passage so as to gradually increase toward the bottom. However, achieving this in a confined space is very difficult.

[0007]

Therefore, according to the present invention, a cooling water pipe connected to the engine body has a water inlet at an appropriate position, and the cooling water pipe extends from the water inlet to the engine body. In a cooling water pipe structure of an engine in which a part of a cooling water pipe is provided with a locally bent part that is bent downward, in parallel with the bent part so that both ends of the bent part communicate with each other. It has an air vent pipe provided,
Further, both ends of the air vent pipe are connected to upper portions of the passage cross section of the cooling water pipe, respectively.

That is, in the present invention, the air bleeding pipe having a necessary minimum length is provided so as to bypass the bent portion bent downward. Of course, the air vent pipe may be thinner than the cooling water pipe, and its tip is opened at the top of the cross section of the passage of the cooling water pipe. At the time of water injection, the cooling water accumulates in the bent portion, but the air downstream of this, that is, the air on the engine body side gathers upward, so that it is pushed out to the upstream side of the bent portion, that is, the water injection port side through the air release pipe, Gas-liquid replacement is performed smoothly without the bending portion becoming an obstacle. The water inlet is provided at an upper part of a radiator which is an end of the cooling water pipe, or at a position in the middle of a cooling water pipe which is an uppermost part of the cooling water system.

In one embodiment of the present invention, one end of the air vent pipe on the engine body side is connected to the highest position on the inner wall surface of the cooling water pipe extending from the bent portion to the engine body. Have been. Thereby, after the injected cooling water fills the inside of the engine main body, the inside of the cooling water pipe gradually fills from the engine main body side, and after the entire area of the engine main body side from the bent portion is injected,
It will reach the end opening of the air vent pipe. That is,
Air does not remain in the cooling water pipe downstream of the bent portion.

[0010] In the third aspect of the present invention, the connection position of the tip of the air vent pipe on the water inlet side with respect to the cooling water pipe is higher than the connection position of the tip of the engine body side. With this, when the water level in the cooling water pipe gradually increases during water injection, the opening at the end of the passage on the engine body side is first closed, and then the passage on the water injection port side is closed. The opening at the end is closed. In other words, the opening at the passage end on the water inlet side is not closed first, and the air bleeding is not hindered.

The height in claim 2 or 3 is based on the attitude of the engine when water is injected, generally, the attitude when the engine is mounted on an automobile or the like.

[0012]

According to the cooling water piping structure for an engine according to the present invention, even if a local bending portion is present in the cooling water piping, the cooling water piping can be reliably moved to the water injection port side without using a separate air release valve. Air can be pushed out, and smooth gas-liquid replacement can be performed. Further, since the air vent pipe has a minimum length required to bypass a local bending portion, there is little restriction on the pipe layout, and as a result, it is possible to achieve a reliable and smooth air vent, and as a result, water injection Work operability is improved.

Further, according to the configuration of the second aspect, the air inside the cooling water pipe on the engine body side than the bent portion can be more reliably discharged.

According to the third aspect of the present invention, the air vent pipe is reliably maintained in the communicating state until the air downstream of the bent portion is completely discharged, and the air remaining near the bent portion is further reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

This embodiment is an example in which the present invention is applied to a V-type engine for automobiles. First, an outline of the configuration of the entire cooling water system will be described with reference to FIG. A water jacket (not shown), which is generally constituted by the cylinder head 3 and serves as a water passage, is formed therein. The engine main body 1 is mounted on a vehicle in a so-called vertical position, and a radiator 4 is disposed at a front position of a vehicle body in front of the vehicle.
The radiator 4 has an upper tank 4a and a lower tank 4b, and a water inlet 6 closed by a radiator cap 5 is provided in the upper tank 4a. A cooling water inlet 9 provided with a water pump 8 together with a known thermostat valve 7 is provided on the front surface of the cylinder head 3 of the engine body 1.
And the lower tank 4b are connected by the lower cooling water passage 10. The lower cooling water passage 10 is substantially entirely constituted by a rubber hose. A cooling water outlet 11 is provided on the rear surface of the cylinder head 3, and the cooling water outlet 11 is connected to the upper tank 4 a by an upper cooling water passage 12.

In such a cooling water system, during normal operation, cooling water is supplied from the lower tank 4b of the radiator 4 to the engine body 1 via the lower cooling water passage 10 with the operation of the water pump 8, and Body 1
After each part is cooled, the cooling water returns to the upper tank 4a of the radiator 4 via the upper cooling water passage 12. On the other hand, at the time of water injection, the cooling water is injected from the water inlet 6 at the upper part of the radiator 4, and flows into the engine body 1 through the upper cooling water passage 12 after the inside of the radiator 4 and the lower cooling water passage 10 are full.

The upper cooling water passage 12 has a metal cooling water pipe 13 extending forward from the rear surface of the cylinder head 3 along the side surface of the cylinder head 3, a cooling water pipe 13 and an upper tank 4a. And a rubber hose 14 connected thereto. Although a bypass passage 15 (see FIGS. 2 and 3) is provided from the cooling water pipe 13 to the cooling water inlet 9 as described later,
In FIG. 1, illustration is omitted.

FIG. 2 is a rear view of the engine body 1, and FIG. 3 is a side view. As shown in these figures, the cooling water pipe 13 is connected to one of the banks via a flange 21 at the end. It is fixed to the rear face of the cylinder head 3, extends from the rear face of the cylinder head 3 of the other bank, and extends forward along the side face of the cylinder head 3. The cooling water pipe 13 is connected to the flange 2
1 and extends along substantially the same height, but the front portion connected to the rubber hose 14 is inclined obliquely upward. Then, in the vicinity of crossing the rear surface of the cylinder head 3 and approaching the side surface of the cylinder head 3, U
The bending portion 22 is bent in a letter shape. This is to avoid interference with a cam angle sensor (not shown) arranged at the rear end of one camshaft of the cylinder head 3. On the side of the cylinder head 3, as shown in FIG. 3, the exhaust manifold mounting surface 23, the cooling water pipe 13 passes above the exhaust manifold (not shown). More specifically, the cooling water pipe 13 is composed of two pipes before and after, and both are connected in series at the connection part 23.
The bypass passage 15 branches off from the vicinity of the front end of the cooling water pipe 13 to the side.

In the present invention, an air vent pipe 31 is provided in parallel with the bending portion 22. This air vent pipe 31
Is a first portion provided near the engine body 1 of the bending portion 22.
A connector 32, a second connector 33 provided near the water inlet 6 of the flexible portion 22, and a rubber hose 34 connecting the two.
, And is disposed above the cooling water pipe 13 and slightly outside. The first connector 32 is provided so as to protrude laterally from the cooling water pipe 13, and as shown in FIG.
The upper cooling water passage 12 in the inside 3 communicates with the uppermost part of a circular passage cross section through an opening 35. The second connector 33 is connected to the upper surface of the cooling water pipe 13 in a substantially vertical direction. Therefore, the internal passage is also opened at the top of the cross section of the upper cooling water passage 12. I have.

Here, when the position of the connection point of the first connector 32 with respect to the upper cooling water passage 12 is compared with the position of the connection point of the second connector 33 with respect to the upper cooling water passage 12, the latter is relatively large. In a high position. Specifically, at least a part of the opening of the passage end of the second connector 33 is higher than the upper edge position of the opening 35 of the passage end of the first connector 32 facing the side. As is apparent from FIG. 3, the engine body 1 is mounted on the vehicle in a posture inclined at an angle of about 2 ° to 5 ° with respect to the horizontal line H so that its front is higher. Yes,
The above-mentioned height is in this vehicle-mounted state.

The opening 35 at the end of the passage of the first connector 32 is provided at the highest position between the bending portion 22 and the engine body 1. Here, the cooling water pipe 13 itself is arranged substantially horizontally from the vicinity of the first connector 32 to the flange portion 21 as shown in FIG. Since the diameter of the pipe 13 is small, and the diameter of the internal passage gradually decreases toward the flange portion 21, focusing on the upper surface position of the inner wall surface where air gathers, the flange portion 2
The first side is lower and gradually increases toward the vicinity of the first connector 32.

In the above configuration, the cooling water is injected from the water injection port 6 above the radiator 4 as described above. The injected cooling water first flows through the inside of the radiator 4 to the lower cooling water passage 10, but the flow is blocked when the thermostat valve 7 is reached, so that the lower cooling water passage 10 and the inside of the radiator 4 Accumulate in After these are filled with water, they flow into the engine body 1 through the upper cooling water passage 12. 2 and 3 show the flow of the cooling water at this time with black arrows. This cooling water is initially supplied to the upper cooling water passage 12.
Flows through the portion near the bottom of the cross section, so that the air in the water jacket is pushed out toward the water inlet 6 through the gap remaining at the top. 2 and 3, the air flow at this time is indicated by white arrows. Then, as a result of gradually filling the inside of the water jacket with the cooling water, the water surface height in the upper cooling water passage 12 gradually increases and eventually reaches a height indicated by reference numeral 36, and the passage cross section of the bending portion 22. Is almost entirely occupied by cooling water. In this state, the bending portion 22
In the above, no air gap remains above the passage cross section of the upper cooling water passage 12. However, the opening 35 located downstream of the bending portion 22, that is, on the side of the engine body 1.
Then, the smooth discharge of the air is continued through the air vent pipe 31, and therefore, the cooling water is injected while being replaced with the air. Therefore, the bending portion 22 does not hinder water injection.

When the water jacket is finally filled, the water level in the upper cooling water passage 12 further rises, and the opening 35 on the engine body 1 side is eventually closed. 1 is completely discharged. When the opening 35 is closed, the opening of the second connector 33 is still above the water surface, and the air bleeding through the air bleeding pipe 31 is not hindered to the end.

As described above, in the configuration of the above-described embodiment, the provision of the air vent pipe 31 enables smooth air vent and water injection regardless of the presence of the bent portion 22.
Since the air vent pipe 31 has a minimum length, there is no occurrence of a defect such as a defect of air vent due to bending in the middle thereof or a clogging.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an entire cooling water system having a piping structure according to an embodiment of the present invention.

FIG. 2 is a rear view of the engine body of the embodiment.

FIG. 3 is a side view of the engine body.

FIG. 4 is an essential part cross-sectional view along the line AA of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine main body 4 ... Radiator 6 ... Water inlet 12 ... Upper cooling water passage 13 ... Cooling water pipe 22 ... Flexure part 31 ... Air release piping

Claims (3)

[Claims] A cooling water pipe connected to an engine body has a water inlet at an appropriate position, and a part of the cooling water pipe extending from the water inlet to the engine body is locally bent downward. In the cooling water piping structure of the engine provided with the portion, an air vent pipe provided in parallel with the flexible portion so that both ends of the flexible portion communicate with each other, and A cooling water piping structure for an engine, wherein both ends are respectively connected to upper portions of a passage cross section of the cooling water piping. 2. An engine body side end of the air vent pipe is connected to a highest position on an inner wall surface of a cooling water pipe extending from the bending portion to the engine body. Item 2. A cooling water piping structure for an engine according to Item 1. 3. The connection position of the tip of the air vent pipe on the water inlet side with respect to the cooling water pipe is higher than the connection position of the tip on the engine body side. Engine cooling water piping structure.