JP3586553B2 - Multi-valve engine cooling system - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multi-valve engine in which a plurality of exhaust valves are arranged for each cylinder, and more particularly to a cooling device for cooling the multi-valve engine.
[0002]
[Prior art]
A multi-valve engine is known in which a plurality of intake / exhaust valves are arranged on a cylinder head for one cylinder, thereby increasing the area of the valve to increase the intake / exhaust efficiency and enabling high speed and high output. .
In this type of multi-valve engine, high-temperature exhaust gas is exhausted from the combustion chamber to the exhaust port via each exhaust valve, so that the wall between the exhaust valves of the cylinder head located between the exhaust valves has the above-mentioned exhaust gas. It is easily heated to high temperature by heating with gas.
[0003]
[Problems to be solved by the invention]
For this reason, large thermal distortion may occur in the wall between the exhaust valves of the cylinder head, and the exhaust valve may be closed in an incomplete state, or the cylinder head may be damaged by thermal distortion.
SUMMARY OF THE INVENTION It is an object of the present invention to reduce the occurrence of thermal distortion on a wall between exhaust valves of a cylinder head in a multi-valve engine.
[0004]
[Means for Solving the Problems]
[Invention of claim 1]
In order to achieve the above object, the invention according to claim 1 is configured as follows, for example, as shown in FIGS.
In a multi-valve engine having a plurality of exhaust valves (5) for one cylinder (3), cooling is performed on a wall (13) between exhaust valves of a cylinder head (2) located between the exhaust valves (5). A passage (12) is provided, and a cooling medium is passed through the cooling passage (12),
Without providing a cooling passage (12) in the wall (31) between the intake and exhaust valves located between the intake valve (4) and the exhaust valve (5), the glow plug (9) is penetrated ,
As illustrated in FIG. 3, at the position of the fuel injection nozzle (8), on a cross-sectional view cut in a direction orthogonal to the axial direction of the crankshaft,
By inclining the glow plug (9) by a predetermined inclination angle (Θ) with respect to the fuel injection nozzle (8) oriented along the central axis (3a) of the cylinder (3), the tip of the glow plug (9) is When approaching the fuel injection nozzle (8) in the cylinder (3),
In the intake port (6) located beside the fuel injection nozzle (8), a part of the peripheral surface at the intermediate portion of the plug body (9a) of the glow plug (9) is exposed.
[0005]
[ Invention of Claim 2 ]
According to a second aspect of the present invention, the configuration of the first aspect of the present invention is further configured as follows.
A plurality of intake valves (4) are provided for one cylinder (3), and a cooling wall is provided between the intake valves (4) of the cylinder head (2) located between the intake valves (4). The configuration is such that no passage (12) is provided.
[0006]
[Action]
[Claim 1]
The invention of claim 1 operates as follows, for example, as shown in FIGS.
The high-temperature exhaust gas is discharged from the combustion chamber to the exhaust port (7) through the exhaust valves (5), so that the thickness between the exhaust valves of the cylinder head (2) located between the exhaust valves (5). Although the wall (13) tends to be heated by the exhaust gas, a cooling medium passes through a cooling passage (12) provided in the wall (13) between the exhaust valves of the cylinder head (2), and the exhaust gas is exhausted. By cooling the inter-valve wall (13), the temperature of the exhaust-valve wall (13) of the cylinder head (2) is suppressed from increasing.
[0007]
[Claim 2]
The second aspect of the present invention operates as follows.
Since intake air having a relatively low temperature passes through the intake valves (4), the wall (14) between the intake valves of the cylinder head (2) located between the intake valves (4) is connected to the exhaust valves (5). It is difficult to raise the temperature as compared to the wall (13) between the exhaust valves of the cylinder head (2) located between them.
[0008]
A cooling passage (12) is provided in the wall (13) between the exhaust valves of the cylinder head (2), which is easily heated to a high temperature. A cooling passage (12) is not provided in the wall (14) between the intake valves of the head (2) so that the wall (14) between the intake valves is not cooled too much by the cooling medium. The temperature difference between the cylinder head (2) around the exhaust valve (5) and the cylinder head (2) around the intake valve (4) can be reduced.
[0009]
In addition, as much as the cooling medium is not supplied to the intake valve wall (14) of the cylinder head (2), the cooling medium is supplied to the exhaust valve wall (13) of the cylinder head (2). The cylinder head (2) in the vicinity of the exhaust valve (5), which is likely to be sent to the cooling passage (12) and is likely to become hot, can be more strongly cooled.
[0010]
【The invention's effect】
[Claim 1]
The invention according to claim 1 has the following effects because it is configured and operates as described above.
Since the cooling passage is provided in the wall between the exhaust valves of the cylinder head located between the plurality of exhaust valves, the wall between the exhaust valves is strongly cooled and is hardly heated. Therefore, it is possible to reliably prevent a large thermal distortion from being generated on the wall between the exhaust valves of the cylinder head, thereby closing the exhaust valve in an incomplete state due to the thermal distortion of the cylinder head, or causing the cylinder head to be thermally damaged. Damage can be reliably prevented.
[0011]
[Claim 2]
The second aspect of the present invention has the following effects since it is configured and operates as described above.
A cooling passage is provided in the wall between the exhaust valves of the cylinder head, which tends to increase the temperature, and the cooling wall is provided in the wall between the intake valves of the cylinder head, which cools the wall between the exhaust valves strongly, while the wall between the exhaust valves is hardly heated. Therefore, the temperature difference between the cylinder head around the exhaust valve and the cylinder head around the intake valve can be reduced. Therefore, the thermal balance of the entire cylinder head is maintained high, and the thermal distortion of the cylinder head due to the difference in temperature depending on the position of the cylinder head can be more reliably prevented.
[0012]
In addition, the cooling medium is easily sent to the cooling passage of the cylinder head between the exhaust valves because the cooling medium need not be supplied to the cylinder wall between the intake valves of the cylinder head. As a result, the cylinder head around the exhaust valve can be more strongly cooled.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a multi-valve multi-cylinder diesel engine to which an embodiment of a multi-valve engine cooling device according to the present invention is applied will be described with reference to FIGS. 1 to 3.
1 is a longitudinal sectional view showing a main part of a cylinder head of the engine, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG. 3 is a longitudinal sectional view showing a main part of the engine.
[0014]
In the cylinder head (2) of the engine (1), two pairs of intake valves (4) and two pairs of exhaust valves (5) are arranged for each cylinder (3). An intake port (6) and an exhaust port (7) are respectively connected to the pair of intake valve (4) and exhaust valve (5). The pair of intake valves (4) and exhaust valves (5) are simultaneously driven to open and close by a valve operating device described later.
The cylinder head (2) has a fuel injection nozzle (8) for injecting fuel into the combustion chamber (11) for each cylinder (3), and a mixture in the combustion chamber (11) is warmed when the cold start is performed. A glow plug (9) is arranged.
[0015]
Further, a cooling passage (12) is formed in the cylinder head (2), and the cooling water passing through the cooling passage (12) is cooled by a radiator (not shown) or a cooling passage (not shown) of the cylinder block (15). 16) and the like, and circulates to the cooling passage (12) of the cylinder head (2).
Further, the cooling passage (12) of the cylinder head (2) is provided between the exhaust valve wall (13) of the cylinder head (2) located between the two exhaust valves (5) of each cylinder (3). , But not on the wall (14) between the intake valves of the cylinder head (2) located between the two intake valves (4) in each cylinder (3). .
[0016]
By configuring the cooling passage (12) of the cylinder head (2) as described above, the following operation can be obtained.
That is, the exhaust valve thick wall (13) of the cylinder head (2) is heated by the high-temperature exhaust gas discharged from the combustion chamber (11) through the exhaust valve (5) to the exhaust port (7). Although it is easy to increase the temperature, the cooling water passing through the cooling passage (12) of the exhaust valve wall (13) cools the exhaust valve wall (13), so that the exhaust valve wall (13) Temperature is prevented. Also, since relatively low-temperature intake air passes through the intake port (6) and the intake valve (4), the wall (14) between the intake valves of the cylinder head (2) is hardly heated to a high temperature. By not providing the cooling passage (12) in the meat wall (14), the meat wall (14) between the intake valves is prevented from being excessively cooled by the cooling water.
[0017]
On the other hand, as shown in FIG. 3, the glow plug (9) is provided on the cylinder head (2) as follows.
That is, the plug insertion hole (17) is made to pass through the cylinder head (2), and a female screw is formed on the upper part of the plug insertion hole (17). The glow plug (9) has an external thread formed on the upper part of the plug body (9a). When the plug body (9a) is inserted into the plug insertion hole (17) and the male screw of the plug body (9a) is screwed into the female screw of the plug insertion hole (17), the plug body (9a The glow plug (9) is fixed to the cylinder head (2) in a state where a part of the peripheral surface at the intermediate portion of ()) is exposed in the intake port (6). The lower portion of the plug body (9a) is sealed with a sealing material (not shown) or the like.
In this embodiment, as shown in FIG. 2, the cooling passage (12) is not provided in the intake / exhaust valve interwall (31) located between the intake valve (4) and the exhaust valve (5). The glow plug (9) is penetrated. Also, as shown in FIG. 3, at a position of the fuel injection nozzle (8), on a sectional view cut in a direction orthogonal to the axial direction of the crankshaft, the direction along the central axis (3a) of the cylinder (3) is shown. By inclining the glow plug (9) by a predetermined inclination angle (Θ) with respect to the fuel injection nozzle (8), the tip of the glow plug (9) approaches the fuel injection nozzle (8) in the cylinder (3). In doing so, a part of the peripheral surface at the intermediate portion of the plug body (9a) of the glow plug (9) is exposed in the intake port (6) located beside the fuel injection nozzle (8). .
[0018]
The above-described valve train is configured as follows.
That is, a rocker arm bracket (21) is fixed to the upper surface of the cylinder head (2) with fixing bolts (22), and the rocker arm bracket (21) supports a rocker arm shaft (23).
A rocker arm (24) corresponding to an intake valve (4) and an exhaust valve (5) is swingably supported on the rocker arm shaft (23). That is, the pair of intake valves (4) are connected to the output portion (25) of the intake valve rocker arm (24) via the valve bridge (27), and the rocker arm (24) for the exhaust valve. The pair of exhaust valves (5) are connected to the output section (25) via a valve bridge (27).
[0019]
The upper end (29) of the push rod (28) is connected to the input section (26) of the rocker arm (24). The push rod (28) swings up and down in conjunction with a valve operating cam shaft (not shown). Thus, the pair of intake valves (4) and the pair of exhaust valves (5) are simultaneously opened and closed simultaneously.
A nozzle pressing plate (30) is fixed to the upper end of the rocker arm bracket (21), and the upper end of the fuel injection nozzle (8) is pressed by the nozzle pressing plate (30). The fuel injection nozzle (8) is prevented from rising.
[0020]
The above embodiment can be modified as follows.
That is, in the above description, two exhaust valves (5) are arranged for each cylinder (3), but three or more exhaust valves (5) may be arranged for each cylinder (3). Good. In this case, too, the cooling passages (12) are provided in the exhaust valve wall (13) of the cylinder head (2) located between the exhaust valves (5) of the cylinders (3). Further, one intake valve (4) may be arranged for each cylinder (3), or three or more intake valves may be arranged for each cylinder (3).
[0021]
Further, the cooling medium flowing through the cooling passage (12) is not limited to cooling water, and may be, for example, oil.
Further, it goes without saying that the present invention can be applied to a multi-valve gasoline engine, and can also be applied to a single cylinder engine.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a multi-valve multi-cylinder diesel engine to which an embodiment of a cooling device for a multi-valve engine according to the present invention is applied, showing a main part of a cylinder head of the engine.
FIG. 2 is a sectional view taken along the line II-II in FIG.
FIG. 3 is a longitudinal sectional view showing a main part of the engine.
[Explanation of symbols]
2 ... Cylinder head, 4 ... Intake valve, 5 ... Exhaust valve, 12 ... Cooling passage, 13 ... Cylinder head wall between exhaust valves, 14 ... Cylinder head wall between intake valves.

Claims (2)

In a multi-valve engine having a plurality of exhaust valves ( 5 ) for one cylinder ( 3 ) ,
Each exhaust valve (5) to the cylinder head (2) of the exhaust valve between the meat wall (13) located between each other a cooling passage (12), to pass a medium for cooling to the cooling passage (12) Make up,
Without providing a cooling passage (12) in the wall (31) between the intake and exhaust valves located between the intake valve (4) and the exhaust valve (5) , the glow plug (9) is penetrated,
At the position of the fuel injection nozzle (8), on a sectional view cut in a direction orthogonal to the axial direction of the crankshaft,
By inclining the glow plug (9) by a predetermined inclination angle (Θ) with respect to the fuel injection nozzle (8) oriented along the central axis (3a) of the cylinder (3), the tip of the glow plug (9) is When approaching the fuel injection nozzle (8) in the cylinder (3),
In the intake port (6) located beside the fuel injection nozzle (8), a part of the peripheral surface at the intermediate portion of the plug body (9a) of the glow plug (9) is exposed. Cooling system for multi-valve engines. The cooling device for a multi-valve engine according to claim 1 ,
A plurality of intake valves (4) are provided for one cylinder (3). Cooling is provided between the intake valve wall (14) of the cylinder head (2) located between the intake valves (4). It was configured not to provide a passage (12),
A cooling device for a multi-valve engine, characterized in that:

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