JPH11223154A - Diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently secure a passage cross section area for an intake port or a water jacket even when a glow plug is arranged in a cylinder head. SOLUTION: A circumferential wall part 6a in an intake port 6 positioned between a circumferential face of a plug main body 9a of a glow plug 9 and the intake port 6 arranged inside a cylinder head 2 is cut off, and a part of the circumferential face in the intermediate part of the plug main body 9a is exposed toward the inside of the intake port 6a. Under this condition, the plug main body 9a of the glow plug 9 is passed through the circumferential wall part 6a of the intake port 6 so as to be supported.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a diesel engine provided with a glow plug for warming an air-fuel mixture in a combustion chamber in order to facilitate a cold start.

[0002]

2. Description of the Related Art Normally, in a diesel engine, a plug body of a glow plug is passed through a cylinder head, and a heat portion of the glow plug is located in a combustion chamber. Is warmed, which facilitates cold start.

Incidentally, in addition to the glow plug, an intake / exhaust port, a water jacket, a fuel injection nozzle and the like are arranged in the cylinder head. For this reason,
Due to the size limitation of the cylinder head, it is difficult to arrange the glow plug on the cylinder head with a margin. In this case, if the passage cross-sectional area of the intake port or the water jacket is reduced to some extent, a sufficient space for disposing the glow plug can be secured in the cylinder head.

[0004]

However, if the passage cross-sectional area of the intake port or the water jacket is reduced to arrange the glow plug in the cylinder head as described above, the following problem occurs. That is, when the glow plug is disposed with the passage cross-sectional area of the intake port reduced, the passage resistance of the intake port increases and the volume efficiency decreases. In addition, when the glow plug is arranged by reducing the passage sectional area of the water jacket,
The cooling efficiency of the cylinder head decreases. It is an object of the present invention to ensure a sufficient passage cross-sectional area of an intake port and a water jacket even if a glow plug is arranged in a cylinder head.

[0005]

Means for Solving the Problems [Invention of claim 1] The invention of claim 1 is, for example, shown in FIG.
As shown in FIG. 2 and FIG. 2, the configuration is as follows. A diesel engine which supports a plug body (9a) of a glow plug (9) through a peripheral wall (6a) of an intake port (6) provided in a cylinder head (2),
The peripheral wall (6a) of the intake port (6) located between the peripheral surface of (9a) and the intake port (6) is deleted, and the plug body (9a) is exposed inside the intake port (6). It is configured as follows.

[Invention of Claim 2] The invention of Claim 2 is, for example, as shown in FIG. 3, configured as follows in the configuration of Claim 1 described above. The shaft core (9b) of the plug body (9a) is configured to pass through the bottom wall (6b) of the peripheral wall (6a) of the intake port (6).

[0007]

The invention of claim 1 operates as follows, for example, as shown in FIGS. The peripheral surface of the plug body (9a) of the glow plug (9) and the intake port (6)
By removing the peripheral wall portion (6a) of the intake port (6) located between the peripheral surface of the plug body (9a) and the intake port
When there is a peripheral wall (6a) of the intake port (6)
The passage cross-sectional area of the intake port (6) can be made larger than that of [see a two-dot chain line diagram in FIG. 2]. Thereby, the intake port (6)
Can reduce the passage resistance and maintain a high volumetric efficiency.

The plug body (9a) of the glow plug (9)
Is exposed inside the intake port (6), so that the exposed portion of the plug body (9a) is less likely to be cooled. That is,
The air in the intake port (6) is less likely to remove the heat of the plug body (9a) than the metal forming the wall of the cylinder head (2). The portion is less likely to be cooled than when the portion is covered by the peripheral wall (6a) of the intake port (6).

[Claim 2] The invention of claim 2 operates as follows, for example, as shown in FIG. The axis (9b) of the plug body (9a) of the glow plug (9) is connected to the intake port (6).
The plug body (9a) is shifted toward the center in the intake port (6) by an amount corresponding to the portion passing through the bottom wall portion (6b) of the peripheral wall portion (6a). As a result, the space occupied by the plug main body (9a) in the peripheral wall (6a) of the intake port (6) is reduced, and the cylinder head (2) is provided with a sufficient space for the space. Therefore, the cooling passage (12) can be enlarged without making the passage sectional area of the intake port (6) too small.

[0010]

[Embodiment 1] The invention of the above-described embodiment 1 has the following effects because it is configured and operates as described above. By removing the peripheral wall of the intake port between the peripheral surface of the plug body of the glow plug and the intake port, the passage cross-sectional area of the intake port can be increased, so that the passage resistance of the intake port can be reduced and the volume can be reduced. High efficiency can be maintained. Therefore, the intake air can be sufficiently supplied to the combustion chamber, and the air-fuel mixture can be sufficiently combusted in the combustion chamber, whereby the output loss of the engine can be reduced.

Further, since the plug body of the glow plug is exposed in the intake port, the exposed portion of the plug body is hardly cooled, and accordingly, the glow plug is hardly cooled excessively. The heating part of the plug is quickly heated.

[Claim 2] The invention of claim 2 has the following effects since it is configured and operates as described above.
As the glow plug moves closer to the center side of the intake port, there is room in the cylinder head, so that the cooling passage in the cylinder head can be enlarged without reducing the passage sectional area of the intake port much. This allows powerful cooling of the cylinder head.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a multi-valve multi-cylinder diesel engine to which the present invention is applied will be described below with reference to FIGS. FIG. 1 is a longitudinal sectional view showing a main part of the engine, and FIG. 2 is a sectional view taken along line II-II in FIG.

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). The pair of intake valve (4) and exhaust valve (5) have an intake port.
(6) and the exhaust port (7) are connected respectively. The pair of intake valves (4) and the exhaust valves (5) are simultaneously driven to open and close simultaneously by a valve gear described later.

The cylinder head (2) is provided with a fuel injection nozzle (8) for injecting fuel into the combustion chamber (11) for each cylinder (3), and a fuel injection nozzle (8) in the combustion chamber (11) when the cold start is performed. A glow plug (9) for warming is arranged. Further, a cooling passage (12) is formed in the cylinder head (2), and cooling water passing through the cooling passage (12) is cooled by a cooling passage (not shown) of a radiator (not shown) or a cylinder block (15). 16) and the like, and circulates to the cooling passage (12) of the cylinder head (2).

On the other hand, the glow plug (9) is provided on the cylinder head (2) as follows. That is, a plug insertion hole (17) is made to pass through the peripheral wall portion (6a) of the intake port (6) in the cylinder head (2), and a female screw is formed on the upper portion of the plug insertion hole (17). Meanwhile, the above glow plug
An external thread is formed on the upper part of the plug body (9a) of (9). Also, the peripheral wall (6a) of the intake port (6) located between the plug insertion hole (17) and the intake port (6) is deleted.
[Refer to a two-dot chain line diagram in FIG. 2].

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 The glow plug (9) is fixed to the cylinder head (2) with a part of the peripheral surface at the intermediate portion of the main body (9a) exposed in the intake port (6).

The lower portion of the plug body (9a) is sealed by a sealing material (not shown) or the like, so that the combustion chamber
The gas in (11) is prevented from leaking into the intake port (6) through a gap between the peripheral surface of the plug body (9a) and the wall of the cylinder head (2).

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 output portion (25) of the rocker arm (24) for the intake valve is connected to the pair of intake valves (4) via the valve bridge (27), and the output portion of the rocker arm (24) for the exhaust valve. (25) has a valve bridge
The pair of exhaust valves (5) are connected via (27).

The input section (2) of the rocker arm (24)
The upper end (29) of the push rod (28) is connected to 6). The push rod (28) is a valve operating cam shaft (not shown).
It swings up and down in conjunction with. This allows
The pair of intake valves (4) and the pair of exhaust valves (5) are simultaneously opened and closed. 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.

Next, a second embodiment of the diesel engine according to the present invention will be described with reference to FIG. The second embodiment has substantially the same configuration as the first embodiment described above, and differs in the following point. That is, the axis (9b) of the plug body (9a) of the glow plug (9) is aligned with the peripheral wall of the intake port (6).
It is configured to pass through the bottom wall portion (6b) in (6a).

Then, the axis (9b) of the plug body (9a)
However, the plug body (9a) is shifted toward the center side in the intake port (6) by an amount corresponding to the portion passing through the bottom wall (6b) of the peripheral wall (6a) of the intake port (6). Accordingly, the cylinder head (2) has a space allowance, and the cooling passage (12a) can be increased without increasing the passage sectional area of the intake port (6) so much that the cooling passage (12) is enlarged. can do. That is, the cooling passage (1) is provided around the exhaust valve (5), which is likely to be heated to a high temperature by the exhaust gas.
As much as 2a) can be added, the cylinder head (2) around the exhaust valve (5) can be strongly cooled.

In FIG. 3 of the second embodiment, the entire peripheral surface of the plug body (9a) of the glow plug (9) is formed by the intake port.
(6) It is exposed inside, but it is not limited to this,
If the axis (9b) of the plug body (9a) passes through the bottom wall portion (6b) of the peripheral wall portion (6a) of the intake port (6), the peripheral surface of the plug body (9a) Part of the peripheral wall of the intake port (6) (6
a) You may be comprised so that it may enter.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a multi-valve multi-cylinder diesel engine to which the present invention is applied, and is a longitudinal sectional view showing a main part of the engine.

FIG. 2 is a sectional view taken along line II-II of FIG.

3 shows a second embodiment of the diesel engine according to the present invention, and is an enlarged view of a cross section corresponding to FIG. 2;

[Explanation of symbols]

2 ... cylinder head, 6 ... intake port, 6a ... peripheral wall of intake port, 6b ... bottom wall at peripheral wall of intake port, 9 ... glow plug, 9a ... plug body of glow plug, 9b ... axis of plug body .

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Aoshima 64 Ishizukitamachi, Sakai-shi, Osaka Inside Kubota Sakai Works

Claims (2)

[Claims] A plug body (9) of a glow plug (9) is attached to a peripheral wall (6a) of an intake port (6) provided in a cylinder head (2).
a) a diesel engine that penetrates and supports a peripheral wall (6a) of the intake port (6) located between the peripheral surface of the plug body (9a) and the intake port (6). A diesel engine, wherein the plug body (9a) is removed so as to be exposed in the intake port (6). 2. The diesel engine according to claim 1, wherein an axis (9b) of the plug body (9a) is connected to the intake port (6).
The diesel engine is configured to pass through a bottom wall portion (6b) of a peripheral wall portion (6a) of the diesel engine.