JP7366879B2 - diesel engine - Google Patents

Description

The present invention relates to a diesel engine, and more particularly, to a diesel engine capable of precise fuel injection.

Conventionally, there is a diesel engine that includes a swirl chamber type combustion chamber, an insertion hole in a cylinder head toward the swirl chamber, and a fuel injector inserted into the insertion hole (for example, see Patent Document 1).

JP2020-67065A (see Figure 1)

[Problem] Precise fuel injection may not be possible.
In the engine of Patent Document 1, when the main body of the fuel injector is disposed within the cylinder head, the fuel injector main body may overheat due to the heat of the cylinder head, making it impossible to perform precise fuel injection.

An object of the present invention is to provide a diesel engine that can perform precise fuel injection.

The main configuration of the present invention is as follows.
As illustrated in FIG. 1(A), a cylinder (3), a cylinder head (1), a vortex chamber (2) in the cylinder head (1), and a main combustion chamber (4) in the cylinder (3). , a communication port (5) that communicates the main combustion chamber (4) and the vortex chamber (2), an insertion hole (1a) in the cylinder head (1) facing the vortex chamber (2), and an insertion hole (1a). In a diesel engine equipped with a fuel injector (7) inserted into the
As illustrated in FIG. 1(A), a sleeve (10) protrudes from the insertion hole (1a) to the outside of the cylinder head (1), and a pressure receiving surface (10) provided at the protruding end (10a) of the sleeve (10). 10b),
The fuel injector (7) includes a main body part (7c) with a large diameter, a nozzle part (7d) with a small diameter, and a pressing surface (7e) formed at a step between the main body part (7c) and the nozzle part (7d). Equipped with
The nozzle part (7d) of the fuel injector (7) is inserted from the inside of the sleeve (10) into the insertion hole (1a), and the fuel injector (7) is pressed toward the vortex chamber (2) by the pressing force (11). The pressure force (11) applied to the fuel injector (7) is received from the pressure surface (7e) of the fuel injector (7) via the washer (12) by the pressure receiving surface (10b) of the sleeve (10). is,
As illustrated in FIG. 1(A), the sleeve (10) includes a sleeve extension cover (28a) extending from the protrusion end (10a) in the protrusion direction, and the sleeve extension cover (28a) connects the washer (12) with the sleeve extension cover (28a). is covered from the outer circumferential side,
The main body (7c) of the fuel injector (7) is fitted into the extension end (28aa) of the sleeve extension cover (28a),
As illustrated in FIG. 1(A) etc., the inner circumferential surface (28ad) of the extension end (28aa) of the sleeve extension cover (28a) and the outer circumferential surface (7cb) of the main body (7c) of the fuel injector (7) ) is sealed with a ring gasket (28ac).

The present invention has the following effects.
<<Effect 1>> Precise fuel injection can be performed.
As illustrated in FIG. 1(A), in this engine, the main body (7c) of the fuel injector (7) is moved away from the cylinder head (1) by the sleeve (10), so the heat of the cylinder head (1) increases. The main body (7c) of the fuel injector (7) is not easily overheated, and precise fuel injection can be performed.
<<Effect 2>> Waterproofing and dustproofing can be achieved from the outer peripheral side of the washer (12) to the inside of the sleeve (10).
As illustrated in FIG. 1(A), in this engine, the washer (12) is covered from the outer circumferential side with the sleeve extension cover (28a), so waterproofing from the outer circumferential side of the washer (12) into the sleeve (10) is prevented. and dustproofing.
<<Effect 3>> Waterproofing and dustproofing can be achieved from the extension end (28aa) of the sleeve extension cover (28a) to the inside of the sleeve extension cover (28a).

FIG. 1(A) is an elevational cross-sectional view of a vortex chamber and its surrounding parts, and FIG. FIG. 1(C) is an enlarged view of FIG. 1(A) in direction C, and FIG. 1(D) is an enlarged view of FIG. 1(A) in direction of arrow D. 2(A) shows a basic example, and FIG. 2(B) shows a first modified example. 3(A) is a basic example, FIG. 3(B) is a modified example 2-1, FIG. 3(C) is a modified example 2-2, FIG. 3(D) shows modification example 2-3. 4(A) is a basic example, FIG. 4(B) is a modified example 3-1, and FIG. 4(C) is a modified example 3-2. It shows.

5(A) is a modification example 4-1, FIG. 5(B) is a modification example 4-2, and FIG. 5(C) is a modification example 4. -3, FIG. 5(D) shows modification 4-4. 6(A) is a basic example, FIG. 6(B) is a modified example 5-1, and FIG. 6(C) is a modified example 5-2. , FIG. 6(D) shows modification example 5-3. 7(A) shows a modification 5-4, and FIG. 7(B) shows a modification 5-5. FIG. 8(A) shows a modification 6-1, and FIG. 8(B) shows a modification 6-2. FIG. 9(A) shows a basic example, and FIG. 9(B) shows a seventh modified example. 10(A) shows a basic example and FIG. 10(B) shows a modified example 8. FIG.

11(A) is a sectional view taken along the line XIA-XIA of FIG. 1(B), and FIG. 11(B) is a sectional view of FIG. 1(B). ), and FIG. 11(C) is a diagram equivalent to FIG. 1(C). 12(A) is a diagram corresponding to FIG. 11(A), FIG. 12(B) is a diagram corresponding to FIG. 11(B), and FIG. (C) is a diagram corresponding to FIG. 11(C). FIG. 11A is a diagram corresponding to FIG. 11A regarding a first comparative example of a fuel injection hole of a fuel injector. FIG. 12 is a diagram corresponding to FIG. 11(A) regarding a second comparative example of a fuel injection hole of a fuel injector. 15(A) is a diagram corresponding to FIG. 11(A), FIG. 15(B) is a diagram corresponding to FIG. 11(B), and FIG. 15(C) is a diagram corresponding to a third comparative example of a fuel injection hole of a fuel injector. 11(C).

1 to 12 are diagrams for explaining a diesel engine according to an embodiment of the present invention. FIG. 1 is a basic example of each part of the engine used in the engine of the embodiment, and FIGS. 2 to 12 are illustrations of the sleeve, sealing structure, etc. used in the embodiment. These are basic examples and modified examples.
Further, FIGS. 13 to 15 are diagrams of comparative examples with respect to basic examples and modified examples regarding fuel injection holes used in the embodiment of the present invention.

In the embodiment of the present invention shown in FIG. 1, a vertical in-line multi-cylinder electronic fuel injection diesel engine is used.
As shown in FIG. 1(A), this engine includes a cylinder (3), a cylinder head (1) assembled on the upper part of the cylinder (3), and a piston (14) fitted inside the cylinder (3). It is equipped with

As shown in Figure 1(A), this engine has a vortex chamber (2) in the cylinder head (1), a main combustion chamber (4) in the cylinder (3), and a vortex chamber (4) in the cylinder head (1). A communication port (5) that communicates the chamber (2), an insertion hole (1a) in the cylinder head (1) facing the vortex chamber (2), and a fuel injector (7) inserted into the insertion hole (1a). We are prepared.

This engine is a 4-cycle engine, and in this engine, compressed air is forced into the vortex chamber (2) from the main combustion chamber (4) through the communication port (5) near the top dead center of the compression stroke. The injection fuel (13) shown in Fig. 11(A) is injected from the fuel injector (7) into the swirling flow (2a) of the compressed air generated in (2), and the combustion gas generated by combustion in the swirl chamber (2) is injected into the main combustion chamber (4) from the communication port (5) shown in FIG. 1(A), and the unburned fuel contained in the combustion gas is mixed with the air in the main combustion chamber (4) and combusted.

As shown in FIG. 1(A), a piston ring (14a) is fitted onto the piston (14), with the cylinder center axis (3a) side being the front side and the cylinder peripheral wall (3b) side being the rear side. ) is provided with a gas guide groove (14b) that becomes shallower as it approaches the front side.
The vortex chamber (2) is spherical and formed within the cylinder head (1). The symbol (2b) in FIG. 1(A) is the center of the vortex chamber (2).
The communication port (5) is formed in a mouthpiece (15) fitted inside the cylinder head (1), and is directed rearward and upwardly toward the vortex chamber (2) from the main combustion chamber (4). The opening (5d) of the communication port (5) on the main combustion chamber (4) side is arranged directly above the rear end (14c) of the gas guide groove (14b).
The main combustion chamber (4) is formed in a space sandwiched between the cylinder head (1) and the piston (14) from above and below within the cylinder (3).
A head gasket (16) is sandwiched between the cylinder (3), the cylinder head (1), and the mouthpiece (15).

As shown in FIG. 1(A), this engine includes a sleeve (10) that protrudes from the insertion hole (1a) to the outside of the cylinder head (1), and a sleeve (10) provided at the protruding end (10a) of the sleeve (10). It is equipped with a pressure receiving surface (10b).
As shown in FIG. 1(A), the fuel injector (7) has a large diameter main body part (7c), a small diameter nozzle part (7d), and a step difference between the main body part (7c) and the nozzle part (7d). It is provided with a pressing surface (7e) formed in the section.
In this engine, the nozzle part (7d) of the fuel injector (7) is inserted from the inside of the sleeve (10) to the insertion hole (1a), and the fuel injector (7) is pushed into the vortex chamber (2) by the pressing force (11). ) side, and the pressing force (11) applied to the fuel injector (7) is received by the pressure receiving surface (10b) of the sleeve (10) from the pressing surface (7e) of the fuel injector (7) via the washer (12). It is configured so that
As shown in FIG. 1(A), the sleeve (10) includes a sleeve extension cover (28a) extending from the protrusion end (10a) in the protrusion direction, and the washer (12) is attached to the sleeve extension cover (28a). Covered from the outside.
The main body (7c) of the fuel injector (7) is fitted into the extension end (28aa) of the sleeve extension cover (28a).

As shown in FIG. 1(A), in this engine, the main body (7c) of the fuel injector (7) is kept away from the cylinder head (1) by the sleeve (10), so the heat of the cylinder head (1) The main body (7c) of the fuel injector (7) is unlikely to overheat, allowing precise fuel injection.
Further, in this engine, since the sleeve extension cover (28a) covers the washer (12) from the outer circumferential side, it is possible to make the inside of the sleeve (10) waterproof and dustproof from the outer circumferential side of the washer (12).
In this engine, the pressing force (11) applied to the fuel injector (7) is generated by the fuel injector (7) receiving the elastic restoring force of a compressed spring plate (not shown).

As shown in FIG. 1(A), the inner peripheral surface (28ad) of the extension end (28aa) of the sleeve extension cover (28a) and the outer peripheral surface (7cb) of the main body (7c) of the fuel injector (7) The space between them is sealed with a ring gasket (28ac).
Therefore, in this engine, it is possible to achieve waterproofing and dustproofing from the extension end (28aa) of the sleeve extension cover (28a) into the inside of the sleeve extension cover (28a).
As shown in FIG. 1(A), a gas seal (7f) is fitted onto the nozzle part (7d), and this gas seal (7f) connects the inner peripheral surface of the insertion hole (1a) with the nozzle part (7d). ) is sealed to prevent combustion gas generated in the vortex chamber (2) from leaking to the outside through the insertion hole (1a).

The fuel injector (7) is of the electronic fuel injection type.
The electronic fuel injector (7) is electronically controlled by the engine ECU, and injects a predetermined amount of fuel (13) at a predetermined timing.
ECU is an abbreviation for electronic control unit.
In this engine, electronic components within the main body (7c) of the fuel injector (7) are less likely to overheat, and precise electronic fuel injection control can be performed.

As shown in FIG. 1(A), in this engine, a valve body (7da) is housed in the nozzle part (7d) of the fuel injector (7), and a valve body (7da) is housed in the main body part (7c) of the fuel injector (7). The electronic components of the (7da) valve drive system (7ca) are housed here.
Therefore, in this engine, the electronic components of the valve drive device (7ca) in the main body (7c) are not easily overheated by the heat of the cylinder head (1), and precise electronic fuel injection control can be performed.
Electronic components of the valve drive device (7ca) include an electromagnetic coil of an electronic solenoid, a piezo element, etc.

As shown in FIG. 1(A), this engine includes an engine cooling air passage (1b), in which the outer peripheral surface (7cb) of the main body (7c) of the fuel injector (7) ) and the outer peripheral surface (10g) of the sleeve (10) are exposed.
In this engine, the heat of the main body (7c) and sleeve (10) of the fuel injector (7) is radiated to the cooling air passing through the engine cooling air passage (1b), and the heat of the cylinder head (1) is used to inject the fuel injector ( The main body (7c) of 7) is not easily overheated, and precise electronic fuel injection control can be performed.
During engine operation, engine cooling air generated by an engine cooling fan (not shown) passes through the engine cooling air passage (1b).

In the engine of FIG. 1(A), the basic example of the sleeve (10) shown in FIG. 2(A) is used, and the sleeve (10) of this basic example is configured as a separate part from the cylinder head (1), It is attached to the cylinder head (1).
Therefore, in this engine, heat transfer from the cylinder head (1) to the sleeve (10) is obstructed at the attachment point of the sleeve (10), and the heat of the cylinder head (1) is transferred to the main body of the injector (7). The electronic components in 7c) are not easily overheated, and precise electronic fuel injection control can be performed.
Furthermore, when the sleeve (10) of this basic example is used, the sleeve (10) of modification example 1 shown in FIG. Compared to the above, the cylinder head (1) has a simpler shape, making it easier to manufacture the cylinder head (1).

In the engine of FIG. 1(A), the cylinder head (1) is provided with a fitting hole (1c) provided at the outer opening of the insertion hole (1a), and the proximal end of the sleeve (10) is inserted into the fitting hole (1c). The part (10c) is fitted inside.
The base end (10c) of the sleeve (10) is press-fitted into the insertion hole (1c).
The proximal end (10c) of the sleeve (10) may be fixed to the insertion hole (1c) by any one of press-fitting, adhesion, welding, press-fitting and gluing, or press-fitting and welding. Adhesive is used for bonding.
In this engine, the cylinder head (1) can be made of cast iron, and the sleeve (10) can be made of steel. The cylinder head (1) is made of aluminum die-casting, and the sleeve (10) may be made of aluminum or other metal. A heat-resistant resin may be used for the sleeve (10). The material of the cylinder head (1) and the material of the sleeve (10) may be the same or different.

As in Modification 1 shown in FIG. 2(B), the sleeve (10) may be integrally molded with the cylinder head (1).
When the sleeve (10) of the modification 1 shown in FIG. 2(B) is used, the sleeve (10) of the basic example shown in FIG. 2(A), that is, the sleeve (10) that is a separate part from the cylinder head (1) This has the advantage of reducing the number of parts compared to when using
The other configurations and functions of Modified Example 2 of FIG. 2(B) are the same as those of the basic example of FIG. 2(A) unless there is any particular contradiction. In FIG. 2(B), the same elements as in FIG. 2(A) are given the same reference numerals as in FIG. 2(A).

In the engine shown in FIG. 1(A), the basic example shown in FIG. 3(A) is used for the sealing structure of the pressure receiving surface (10b) of the sleeve (10).
As shown in FIG. 3(A), in this basic example, the pressure contact between the pressing surface (12a) of the washer (12) and the pressure receiving surface (10b) of the sleeve (10) is made only by the pressing force (11). Sealed.

The sealing structure of the pressure receiving surface (10b) of the sleeve (10) is as shown in Modification 2-1 shown in FIG. 10b) may be sealed with an adhesive (17).
When this modification 2-1 is used, the sealing by pressure bonding is strengthened by the adhesive (17), and the sealing performance is improved.
In this case, it becomes difficult for water and dust to enter the sleeve (10) from between the pressing surface (12a) of the washer (12) and the pressure receiving surface (10b) of the sleeve (10). Water and dust that have entered the sleeve (10) enter the fuel injector (7) and cause its failure. Further, water that enters the sleeve (10) before baking the engine is vaporized by the heat during baking, causing the coating to swell from the inside and causing peeling.

The sealing structure of the pressure receiving surface (10b) of the sleeve (10) is as shown in Modification 2-2 shown in FIG. 10b) may be sealed with grease (18).
According to this modification 2-2, the sealing by pressure bonding is strengthened by the grease (18), and the sealing performance is improved.

The sealing structure of the pressure receiving surface (10b) of the sleeve (10) is as shown in Modification 2-3 shown in FIG. 10b) may be sealed with a sheet gasket (19).
When this modification 2-3 is used, the sealing by pressure bonding is strengthened by the sheet gasket (19), and the sealing performance is improved.
Materials such as metal, resin, and rubber can be used for the sheet gasket (19).

In the engine of FIG. 1(A), the basic example shown in FIG. 4(A) is used for the pressing surface (12a) of the washer (12) and the pressure receiving surface (10b) of the sleeve (10).
In the basic example shown in FIG. 4(A), the pressure receiving surface (10b) of the sleeve (10) and the pressing surface (12a) of the washer (12) are both composed of only flat surfaces.

The pressing surface (12a) of the washer (12) and the pressure receiving surface (10b) of the sleeve (10) are similar to the sleeve as shown in Modification 3-1 and Modification 3-2 shown in FIGS. 4(B) and 4(C). Concentric circular or spiral grooves (20) extending in the circumferential direction are formed on both or one of the pressure receiving surface (10b) of (10) and the pressing surface (12a) of the washer (12), Good too.
In modification 3-1 shown in FIG. 4(B), concentric circular grooves (20) are formed, and in modification 3-2 shown in FIG. 4(B), spiral grooves (20) are formed. There is.
When Modification 3-1 and Modification 3-2 are used, the pressure contact area between the pressing surface (12a) of the washer (12) and the pressure receiving surface (10b) of the sleeve (10) is reduced by the groove (20). Contact pressure increases and sealing performance improves.
Furthermore, even if water or dust enters the groove (20), it is difficult for the water or dust to enter the sleeve (10) because it moves along the groove (20) in the circumferential direction.

The sealing structure of the pressure receiving surface (10b) of the sleeve (10) is as shown in Modifications 4-1 to 4-3 shown in FIGS. 5(A) to 5(C). A ring gasket (22) fitted into a recessed ring groove (21) may be used.
The ring gasket (22) is an O-ring (22a) in Modification 4-1 shown in FIG. 5(A), and an X-ring (22b) having an X-shaped cross section in Modification 4-2 shown in FIG. 5(B). ), but in the modified example 4-3 shown in FIG. 5(C), a triangular ring (22c) having a triangular cross section is used.
When the ring gasket (22) of Modifications 4-1 to 4-3 is used, the pressing surface (12a) of the washer (12) is ) and the pressure receiving surface (10b) of the sleeve (10) can be reliably sealed.
The ring gasket (22) is made of rubber.

The sealing structure of the pressure receiving surface (10b) of the sleeve (10) may be one using an elastic end (10ab) as in Modification 4-4 shown in FIG. 5(D).
In modification 4-4, the sleeve (10) includes a main body (10ca) on the proximal end (10c) side and an elastic end (10ab) that constitutes a part of the protruding end (10a) . The end portion (10ab) and the main body portion (10ca) are tightly fitted, and the elastic end portion (10ab) is made of a material having a smaller elastic modulus (that is, easier to elastically deform) than the main body portion (10ca) and the washer (12). A pressure receiving surface (10b) of the sleeve (10) is formed at the elastic end (10ab).

When the elastic end (10ab) of this modification 4-4 is used, the washer (12) is pressed by the elastic restoring force of the elastic end (10ab) that is supported by the main body (10ca) in a tight fit and without displacement. Sealing between the surface (12a) and the pressure receiving surface (10b) of the sleeve (10) can be ensured.
In this case, since the elastic end (10ab) functions as a gasket, there is no need for a dedicated gasket to seal the pressure receiving surface (10b) of the sleeve (10).
In addition, as in Modifications 2-1 and 2-2 of FIGS. 3(B) and 3(C), there is a gap between the pressing surface (12a) of the washer (12) and the pressure receiving surface (10b) of the sleeve (10). It may be sealed with adhesive (17) or grease (18).
When the main body part (10ca) and the washer (12) are made of steel, the elastic end part (10ab) may be made of copper, aluminum, rubber, resin, etc., which have a smaller elastic modulus than steel.

In Modification 4-4, the elastic end (10ab) and main body (10ca) are tightly fitted with a nested spigot structure.
That is, the main body (10ca) of the sleeve (10) is provided with a fitting groove (10cb) having an L-shaped inner surface in cross section on the opening periphery of the elastic end (10ab), and the elastic end (10ab) is provided with a fitting groove (10cb) having an L-shaped cross section. The cylindrical part (10ac) is tightly fitted with the cylindrical part (10cb), and the cylindrical part (10ac) extends in the radial direction along the open end surface (10cc) of the main body part (10ca) on the elastic end (10ab) side. A flange portion (10ad) is provided, and the open end surface (10ae) of the flange portion (10ad) is the pressure receiving surface (10b) of the sleeve (10).

The inner circumferential side of the sleeve (10) of the engine in Fig. 1 (A) does not have a gasket and does not have a sealing function like the basic example in Fig. 6 (A), but the inner circumferential side of the sleeve (10) has a sealing function. In order to have this, the inner peripheral surface (10d) of the sleeve (10) is recessed, as shown in Modifications 5-1 to 5-4 shown in FIGS. 6(B) to 7(D) and 7(A). A sealing structure using a ring gasket (24) fitted into the ring groove (23) may also be used.
The ring gasket (24) is an O-ring (24a) in Modification 5-1 shown in FIG. 6(B), and an X-ring (24b) having an X-shaped cross section in Modification 5-2 shown in FIG. 6(C). ), a triangular ring (24c) with a triangular cross section is used in Modification 5-3 shown in FIG. 6(D), and a seal lip ring (24d) is used in Modification 5-4 shown in FIG. 7(A). ing. The seal lip ring (24d) includes a seal lip (24da) on the inner periphery.
The seal lip ring (24d) is press-fitted into the ring groove (23). The ring gasket (24) is pressed against the outer peripheral surface (7de) of the nozzle portion (7d) of the fuel injector (7).

When the ring gasket (22) of Modifications 5-1 to 5-4 is used, the elastic restoring force of the ring gasket (22), which is difficult to displace within the ring groove (21), allows the inner peripheral surface of the sleeve (10) to (10d) and the outer peripheral surface (7de) of the nozzle portion (7d) of the fuel injector (7) can be reliably sealed.

The sealing structure on the inner peripheral side of the sleeve (10) includes a ring gasket (24) fixed to the inner peripheral surface (10d) of the sleeve (10) by baking, as shown in Modification 5-5 shown in FIG. 7(B). ) may be used.
In modification 5-5 shown in FIG. 7(B), a triangular ring (24c) having a triangular cross section is used.
A plurality of these triangular rings (24c) are arranged in the axial direction of the inner peripheral surface (10d) of the sleeve (10).
The triangular ring (24c) is in pressure contact with the outer peripheral surface (7de) of the nozzle portion (7d) of the fuel injector (7).

When the ring gasket (24) of this modification 5-5 is used, the elastic restoring force of the ring gasket (22), which does not shift due to seizure, allows the inner circumferential surface (10d) of the sleeve (10) and the fuel injector (7) to Sealing between the nozzle portion (7d) and the outer circumferential surface (7de) can be ensured.

The sealing structure on the inner circumferential side of the sleeve (10), as shown in Modification 6-1 shown in FIG. An embedded seal (25) embedded between the outer circumferential surface (7de) of 7d) may be used.
The embedded seal (25) is in close contact with the inner peripheral surface (10d) of the sleeve (10) and the outer peripheral surface (7de) of the nozzle portion (7d) of the fuel injector (7).
As the material of the embedded seal (25), resin such as rubber or acrylic can be used.

When the embedded seal (25) of this modification 6-1 is used, the embedded seal (25) does not shift when embedded, and the inner circumferential surface (10d) of the sleeve (10) and the nozzle part (7d) of the fuel injector (7) ) can be reliably sealed with the outer circumferential surface (7de).

The sealing structure on the inner circumferential side of the sleeve (10) is formed by connecting the inner circumferential surface (10d) of the sleeve (10) and the nozzle portion ( A filling sealing agent (26) filled between the outer circumferential surface (7de) of 7d) and the outer peripheral surface (7de) may be used.
The filling sealant (26) is filled in the gap between the inner circumferential surface (10d) of the sleeve (10) and the outer circumferential surface (7de) of the nozzle portion (7d) of the fuel injector (7).
Grease or resin can be used as the material for the filling sealant (26).
The peripheral wall of the sleeve (10) is provided with an injection hole (10e) for injecting the filling sealant (26).
After filling and sealing agent (26) is injected into the injection hole (10e) , the injection hole (10e) is closed with a plug (10f).

When the filling sealing agent (26) of this modification 6-2 is used, the filling sealing agent (26) is filled with the inner peripheral surface (10d) of the sleeve (10) and the nozzle portion (7d) of the fuel injector (7). The sealing between the outer peripheral surface (7de) and the outer circumferential surface (7de) can be ensured.

In the engine shown in Fig. 1(A), the outer peripheral side of the washer (12) is made waterproof and dustproof only by the sleeve extension cover (28a) as in the basic example shown in Fig. 9(A). As in modification 7 of B), an attachment cover (28b) attached to the fuel injector (7) may be added.
The mounting cover (28b) is locked to the main body (7c) of the fuel injector (7).

In this engine, the mounting cover (28b) allows the inner peripheral surface (28ad) of the extension end (28aa) of the sleeve extension cover (28a) to be connected to the outer peripheral surface (7cb) of the main body (7c) of the fuel injector (7). Waterproofing and dustproofing can be achieved from the sealed area into the sleeve extension cover (28a).

The basic examples and modified examples shown in FIGS. 2 to 9 can be freely combined with each other.
FIG. 10(A) is a basic example of a combination of the basic examples shown in FIGS. 2 to 9. FIG. 10(B) is a modified example of a combination of the adhesive (17) of Modified Example 2-1 of FIG. 3(D) and the elastic end portion (10ab) of Modified Example 4-4 of FIG. 5(D). It is 8. Modification 8 includes the structure of the pressure receiving surface of the sleeve shown in FIGS. 4(B) and (C), and the sealing structure of the inner peripheral side of the sleeve shown in FIGS. 6(B) to (D) and 7(A) and (B). may be combined.

Next, the arrangement of the tip of the fuel injector (7) will be explained.
As shown in FIG. 1(B), the fuel injector (7) is provided with a fuel injection hole (9) at the tip surface (7db) of the nozzle portion (7d) facing the vortex chamber (2).
As shown in FIG. 1(A), in this engine, a part of the tip surface (7db) of the nozzle portion (7d) protrudes into the vortex chamber (2).
In this engine, the entire tip surface (7db) of the nozzle portion (7d) may protrude into the vortex chamber (2).

In this engine, as shown in FIG. 1(A), part or all of the tip surface (7db) of the nozzle portion (7d) of the fuel injector (7) protrudes into the vortex chamber (2). The combustion flame near the outlet of the fuel injection hole (9) shown in 11(A) and 12(A) is easily blown away by the swirling flow (2a) shown in FIG. 1(A), and the heat of the combustion flame causes the fuel injector ( The electronic components of the valve drive device (7ca) in the main body (7c) of 7) are not easily overheated, and precise electronic fuel injection control can be performed.

Next, the fuel injection hole (9) of the fuel injector (7) will be explained.
FIG. 11 shows a basic example of the fuel injection hole (9), and FIG. 12 shows a modification 9.
As shown in FIGS. 11(A) and 12(A), the fuel injection hole (9) has a tapered shape that widens at the front.

In this engine, as shown in FIGS. 11(A) and 12(A), the fuel injection hole (9) has a tapered shape, so even if soot accumulates at the outlet of the fuel injection hole (9), Fuel injection is less likely to be disturbed, and precise fuel injection control can be performed regardless of soot accumulation at the outlet of the fuel injection hole (9) of the fuel injector (7).

In addition, in this engine, as shown in Fig. 1(A), part or all of the tip surface (7db) of the nozzle part (7d) of the fuel injector (7) protrudes into the vortex chamber (2). , the combustion gas near the outlet of the fuel injection hole (9) shown in FIGS. 11(A) and 12(A) is easily blown away by the swirling flow (2a) shown in FIG. 1(A), and the soot in the combustion gas is It is difficult to grow at the exit of the fuel injection hole (9).

As shown in FIGS. 1(A) and 1(B), a flat vortex guide surface (7dc) is formed around the fuel injection hole (9) on the tip surface (7db) of the nozzle portion (7d) of the fuel injector (7). It is equipped with
As shown in FIG. 1(A), the entire vortex guide surface (7dc) protrudes into the vortex chamber (2).
In this engine, a part of the vortex guide surface (7dc) may protrude into the vortex chamber (2).

As shown in FIG. 1(A), in this engine, at least a part of the vortex guide surface (7dc) protrudes into the vortex chamber (2), so the swirling flow ( 2a) is guided by the vortex guide surface (7dc), the swirl flow (2a) smoothly swirls inside the vortex chamber (2), the compressed air and the injected fuel (13) are mixed well, and the swirl flow (2a) is guided by the vortex guide surface (7dc). ) is difficult to generate soot.
The fuel injection hole (9) is formed on the most convex surface (7dd) in the center of the distal end surface (7db) of the nozzle portion (7d).

As shown in FIGS. 1(B), 11(B), and 12(B), this engine includes a plurality of fuel injection holes (9) for each fuel injector (7).
Therefore, the injected fuel (13) shown in 11(B) and 12(B) is widely dispersed in the vortex chamber (2), and the mixture of the compressed air and the injected fuel (13) is improved, and the vortex chamber (2) ) is difficult to generate soot.

As shown in FIGS. 1(B), 11(B), and 12(B), six fuel injection holes (9) are provided for each fuel injector (7).
In this engine, it is desirable to provide 2 to 6 fuel injection holes (9) for each fuel injector (7).

In the basic example of the fuel injection hole (9) shown in FIGS. 1(B), 11(A), and 11(B), the inlet opening (9a) 6 of the fuel injection hole (9) of one fuel injector (7) Assuming that the total opening area of the cylinders is A square mm and the displacement of one cylinder is C cubic mm, the A/C value obtained by dividing the former value A by the latter value C is 0.75 × 10 ^-6 . I did it like that. Specifically, the total opening area A of the six inlet openings (9a) of the fuel injection holes (9) was 0.224 square mm, and the displacement C for one cylinder was 299,000 cubic mm. The same thing was done in Modified Example 9 of the fuel injection hole (9) shown in FIG.
In this engine, it is desirable that the A/C value is between 0.5×10 ⁻⁶ and 1.0×10 ⁻⁶ .

If the A/C value is less than 0.5×10 ^-6 , the total opening area A of the inlet opening (9a) of the fuel injection hole (9) may be insufficient, and the necessary output may not be obtained. . When the A/C value exceeds 1.0×10 ^-6 , the total opening area A of the inlet opening (9a) of the fuel injection hole (9) becomes excessive, the fuel injection speed is slow, and the vortex chamber ( 2) The oil droplets of the injected fuel (13) do not become fine within the vortex chamber (2), resulting in poor mixing of the compressed air and the injected fuel, and soot is likely to be generated within the vortex chamber (2).
On the other hand, when the A/C value is between 0.5×10 ^-6 and 1.0×10 ^-6 , the necessary output can be obtained and soot is hardly generated in the vortex chamber (2). .

In the basic example of the fuel injection hole (9) shown in FIG. 11(A), the total opening area of the six outlet openings (9b) of the fuel injection hole (9) of one fuel injector (7) is assumed to be B square mm. , assuming that the total opening area of the six inlet openings (9a) of the fuel injection holes (9) of one fuel injector (7) is A square mm, the former value B is divided by the latter value A, which is B/A. The value has been changed to 1.26 (see note). Specifically, the total opening area A of the six inlet openings (9a) of the fuel injection hole (9) is 0.224 square mm, and the six outlet openings (9b) of the fuel injection hole (9) are as described above. The total opening area B was 0.282 square mm. In modification 9 of the fuel injection hole (9) shown in FIG. 12(A), the value of B/A is slightly larger than 1.26.
In this engine, it is desirable that the B/A value is between 1.08 and 1.44.

If the value of B/A is less than 1.08, the total opening area B of the outlet opening (9b) is too small compared to the total opening area A of the inlet opening (9a) of the fuel injection hole (9), and the fuel A small amount of soot deposited at the outlet of the injection hole (9) may interfere with fuel injection and reduce the accuracy of fuel injection control.
If the value of B/A exceeds 1.44, the total opening area B of the outlet opening (9b) is too large compared to the total opening area A of the inlet opening (9a) of the fuel injection hole (9), and the fuel The growth rate of soot deposits at the outlet of the injection hole (9) is fast, and a large amount of soot deposits may obstruct fuel injection and reduce the accuracy of fuel injection control.
On the other hand, when the B/A value is between 1.08 and 1.44, fuel injection is not hindered by a small amount of soot deposits, and soot deposits at the exit of the fuel injection hole (9) The growth rate of substances is slow, and the accuracy of fuel injection control is less likely to deteriorate.

The reason why the growth rate of soot deposits at the exit of the fuel injection hole (9) becomes faster when the value of B/A exceeds 1.44, whereas the growth rate slows down when the value is 1.44 or less. , is estimated as follows. That is, in the former case, the gap (9h) formed around the injected fuel (13) at the exit of the fuel injection hole (9) becomes too large, and a large amount of combustion gas containing soot flows into this gap (9h). Whereas soot deposits grow rapidly, in the latter case, the gap (9h) formed around the injected fuel (13) at the exit of the fuel injection hole (9) becomes a moderate size, and soot deposits grow rapidly. This is presumed to be because the growth rate of the substance and the removal rate of soot deposits by the injected fuel (13) are comparable, and the soot deposits that have grown at the outlet of the fuel injection hole (9) are immediately removed by the injected fuel. .

As shown in FIG. 2(C), in this engine, the vortex chamber side extension line (7b) of the injector center axis (7a) passes through the communication port (5), and as shown in FIG. 11(B), multiple The (6) fuel injection holes (9) are arranged around the injector center axis (7a), and as shown in FIG. 11(C), the plural (6) fuel injection holes (9) The total number (six) of the extension lines (9d) on the vortex chamber side of the injection hole center axis (9c) are made to pass through the communication port (5).
In this engine, only a part of the total number (six) of the vortex chamber side extension lines (9d) may pass through the communication port (5).
In this engine, a large amount of injected fuel (13) is injected into the main combustion chamber (4) through the communication port (5), so excessive combustion in the vortex chamber (2) is prevented and the vortex chamber (2) is injected into the main combustion chamber (4). ), it is difficult to generate soot.
A plurality of (six) fuel injection holes (9) are arranged at constant intervals around the injector center axis (7a) in the circumferential direction of the most protruding surface (8a) of the injector tip surface (8). has been done.

In the fuel injection hole (9) of modification 9 shown in FIG. 12, as shown in FIG. 12(C), the extension line (7b) of the injector center axis (7a) on the vortex chamber side passes through the communication port (5). , as shown in FIG. 12(B), a plurality of (six) fuel injection holes (9) of each fuel injector (7) are arranged around each injector center axis (7a), and as shown in FIG. ), some of the extension lines (9d) on the vortex chamber side of the injection hole center axis (9c) of the plurality (6) fuel injection holes (9) of each fuel injector (7) (5) ) abut against the peripheral edge (5b) of the vortex chamber side opening (5a) of the communication port (5). The remaining number (1) passes through the communication port (5).
In this engine, the total number (six) may abut against the peripheral edge (5b) of the vortex chamber side opening (5a) of the communication port (5).
In this engine, since a large amount of injected fuel (13) is injected into the main combustion chamber (4) through the communication port (5), excessive combustion in the vortex chamber (2) is prevented and the vortex chamber (2) is injected into the main combustion chamber (4). ), it is difficult to generate soot.

As shown in FIG. 12(C), in the fuel injection hole (9) of Modification Example 9, the front and rear sides are perpendicular to each other when viewed in a direction parallel to the vortex chamber side extension line (7b) of the injector center axis (7a). Assuming a similar imaginary line (5c) similar to the vortex chamber side opening (5a) in which each dimension in the direction and lateral direction is enlarged by 1.5 times, this similar imaginary line (5c) and the vortex chamber The peripheral surface of the vortex chamber between the side opening (5a) and the vortex chamber side opening (5a) is the peripheral edge of the vortex chamber side opening (5a) where the vortex chamber side extension line (9d) of the injection hole center axis (9c) of the fuel injection hole (9) abuts. (5b).
In modification 9 of the fuel injection hole (9) shown in FIG. 12, the same elements as in the basic example of the fuel injection hole (9) shown in FIG. 11 are given the same reference numerals as in FIG. The elements of the modified example of the fuel injection hole (9) shown in FIG. 12 have the same structure and function as the elements of the basic example of the fuel injection hole (9) shown in FIG. 11, unless otherwise specified.

When we investigated the soot generation situation in the vortex chamber (2), we found that the total number of extension lines (9d) on the vortex chamber side of the injection hole center axis (9c) of the multiple (6) fuel injection holes (9) ( The basic example shown in Fig. 11 where 6 pieces) pass through the communication port (5), and Fig. 12 where some of the pieces (5 pieces) abut against the peripheral edge (5b) of the vortex chamber side opening (5a) of the communication port (5). In Modified Example 9, compared to the third comparative example of FIG. The amount of soot generated was small.
In the third comparative example shown in FIG. 15, the same elements as the basic example shown in FIG. 11 and the modified example shown in FIG. 12 are given the same reference numerals as those in FIGS. The same applies to the first comparative example shown in FIG. 13 and the second comparative example shown in FIG. 14.

As shown in FIG. 11(A), in the basic example of the fuel injection hole (9), the center axis (9c) of each injection hole (or its extension on the vortex chamber side (9d)) is expanded with respect to the injector center axis (7a). The opening angle (α) is 4°.
As shown in FIG. 12(A), in modification 9 of the fuel injection hole (9), the center axis (9c) of each injection hole (or its extension on the vortex chamber side (9d)) with respect to the injector center axis (7a) is The expansion angle (α) is 7°.
In this engine, the expansion angle (α) of each injection hole center axis (9c) (or its extension on the vortex chamber side (9d)) with respect to the injector center axis (7a) is preferably 4° to 7°. .

When the expansion angle (α) is less than 4°, parts of the plurality of injected fuels (13) are likely to overlap each other, and soot is likely to be generated within the vortex chamber (2).
When the expansion angle (α) exceeds 7°, most of the injected fuel (13) does not pass through the communication port (5) and collides with the inner surface of the vortex chamber (2). Soot is likely to be generated due to excessive combustion.
On the other hand, when the expansion angle (α) is 4° to 7°, soot is hardly generated in the vortex chamber (2).

When we investigated the soot generation situation in the vortex chamber (2), we found that in the basic example (Fig. 11) where the expansion angle (α) is 4° and the modified example 9 (Fig. 12) where the expansion angle (α) is 7°, the expansion angle (α) is 0°. Compared to the 1st comparative example (FIG. 13), the 1° second comparative example (FIG. 14), and the 10° third comparative example (FIG. 15), less soot was generated in the vortex chamber (2).

In the fuel injection holes (9) of the basic example shown in FIG. 11(A), the taper angle (β) of each fuel injection hole (9) is 12°.
In modification 9 of the fuel injection holes (9) shown in FIG. 12(A), the taper angle (β) of each fuel injection hole (9) is 18°.
In this engine, the taper angle (β) is preferably 12° to 18°.

If the taper angle (β) is less than 12°, the outlet opening (9b) is too small compared to the inlet opening (9a) of the fuel injection hole (9), and a small amount of dirt may accumulate at the outlet of the fuel injection hole (9). The soot may interfere with fuel injection, reducing the accuracy of fuel injection control.
If the taper angle (β) exceeds 18°, the outlet opening (9b) is too large relative to the inlet opening (9a) of the fuel injection hole (9), and soot may accumulate at the outlet of the fuel injection hole (9). The growth rate of soot is fast, and a large amount of soot deposits may obstruct fuel injection and reduce the accuracy of fuel injection control.
On the other hand, when the taper angle (β) is between 12° and 18°, fuel injection is not hindered by a small amount of soot deposits, and the soot deposits grow at the exit of the fuel injection hole (9). The speed is slow and the accuracy of fuel injection control is less likely to decrease.

When we investigated the growth rate of soot deposits at the outlet of the fuel injection hole (9), we found that in the basic example (Fig. 11) where the taper angle (β) is 12° and the modified example 9 (Fig. 12) where the taper angle (β) is 18°. Compared to the first comparative example at 0° (Fig. 13), the second comparative example at 6° (Fig. 14), and the third comparative example at 24° (Fig. 15), the amount of soot at the outlet of the fuel injection hole (9) was The growth rate of the deposit was slow.

As in the third comparative example in FIG. 15, when the taper angle (β) exceeds 18°, the growth rate of soot deposits increases at the outlet of the fuel injection hole (109), whereas The reason why the growth rate becomes slow when the taper angle (β) is 18° or less, as in the basic example and Modification 9 in FIG. 12, is estimated as follows. That is, in the former case, a relatively large gap (109h) is formed around the injected fuel (113) at the exit of the fuel injection hole (109), and a large amount of combustion gas containing soot flows into this large gap (109h). Whereas soot deposits grow rapidly, in the latter case, the gap (9h) around the injected fuel (13) at the exit of the fuel injection hole (9) becomes moderately large, and the soot deposits grow rapidly. It is presumed that this is because the speed and the removal speed of soot deposits by the injected fuel (13) are comparable, and the soot deposits that have grown at the exit of the fuel injection hole (9) are immediately removed by the injected fuel.

As shown in FIG. 11(A), in the basic example of the fuel injection hole (9), the included angle between the injector center axis (7a) and the inner circumferential surface (9g) of each injection hole along the injector center axis (7a) is (γ) is assumed to be 1°.
As shown in FIG. 12(A), in the modification 9 of the fuel injection hole (9), there is a gap between the injector center axis (7a) and the inner circumferential surface (9g) of each injection hole along the injector center axis (7a). The angle (γ) is 3°.
In this engine, the included angle (γ) is preferably 1° to 3°.

When the included angle (γ) is less than 1°, parts of the plurality of injected fuels (13) are likely to overlap each other, and soot is likely to be generated within the vortex chamber (2). When the expansion angle (α) exceeds 3°, most of the injected fuel (13) does not pass through the communication port (5) and collides with the inner surface of the vortex chamber (2). Soot is likely to be generated due to excessive combustion.
On the other hand, when the included angle (γ) is 1° to 3°, soot is hardly generated within the vortex chamber (2).

When we investigated the soot generation situation in the vortex chamber (2), we found that in the basic example (Fig. 11) where the included angle (γ) is 1° and the modified example 9 (Fig. 12) where the included angle (γ) is 3°, the first Compared to the comparative example (FIG. 13) and the 4° comparative example (not shown), the amount of soot generated in the vortex chamber (2) was smaller.

As shown in FIG. 11(A), in the basic example of the fuel injection hole (9), the inlet opening edge (9e) of the fuel injection hole (9) has a sharp pin angle (9f) that is not chamfered. ing.
Also in modification 9 of the fuel injection hole (9) shown in FIG. 12(A), the inlet opening edge (9e) of the fuel injection hole (9) is provided with a sharp pin angle (9f) that is not chamfered. .

In this engine, the inlet opening edge (9e) of the fuel injection hole (9) is left with a sharp pin angle (9f) that is not chamfered, thereby eliminating the need for chamfering and manufacturing the fuel injector (7). becomes easier.
In addition, in this engine, the fuel injector (7) injects fuel into the vortex chamber (2), so the fuel injection pressure is lower than that of a direct injection type, and the pin angle (9f) due to the fuel injection pressure is reduced. Wear is less likely to occur, and fuel injection accuracy is less likely to deteriorate due to this.

The pin angle (9f) is a sharp opening edge with an R of 0.1 mm or less.

(1)...Cylinder head, (1a)...Insertion hole, (1b)...Engine cooling air passage, (2)...Vortex chamber, (3)...Cylinder, (4)...Main combustion chamber, (5)...Communication port , (6)...Insertion hole, (7)...Fuel injector, (7c)...Body part, (7cb)...Outer peripheral surface, (7d)...Nozzle part, (7db)...Tip surface, (7dc)...Vortex guide surface , (10)...Sleeve, (10a)...Protruding end, (10b)...Pressure receiving surface, (11)...Press force, (12)...Washer, (12a)...Press surface, (17)...Adhesive, ( 18) Grease, (19) Sheet gasket, (20) Groove, (28a) Sleeve extension cover, (28aa) Extension end, (28ac) Ring gasket, (28ad) Inner peripheral surface.

Claims (8)

A cylinder (3), a cylinder head (1), a vortex chamber (2) in the cylinder head (1), a main combustion chamber (4) in the cylinder (3), a main combustion chamber (4) and a vortex chamber. (2), an insertion hole (1a) in the cylinder head (1) facing the vortex chamber (2), and a fuel injector (7) inserted into the insertion hole (1a). In addition, in diesel engines,
A sleeve (10) protruding from the insertion hole (1a) to the outside of the cylinder head (1), and a pressure receiving surface (10b) provided at the protruding end (10a) of the sleeve (10),
The fuel injector (7) includes a main body part (7c) with a large diameter, a nozzle part (7d) with a small diameter, and a pressing surface (7e) formed at a step between the main body part (7c) and the nozzle part (7d). Equipped with
The nozzle part (7d) of the fuel injector (7) is inserted from the inside of the sleeve (10) into the insertion hole (1a), and the fuel injector (7) is pressed toward the vortex chamber (2) by the pressing force (11). The pressure force (11) applied to the fuel injector (7) is received from the pressure surface (7e) of the fuel injector (7) via the washer (12) by the pressure receiving surface (10b) of the sleeve (10). is,
The sleeve (10) includes a sleeve extension cover (28a) extending from the projecting end (10a) in the projecting direction, and the sleeve extension cover (28a) covers the washer (12) from the outer peripheral side.
The main body (7c) of the fuel injector (7) is fitted into the extension end (28aa) of the sleeve extension cover (28a),
The inner peripheral surface (28ad) of the extended end (28aa) of the sleeve extension cover (28a) and the outer peripheral surface (7cb) of the main body (7c) of the fuel injector (7) are sealed with a ring gasket (28ac). A diesel engine characterized by: The diesel engine according to claim 1 ,
Equipped with an engine cooling air path (1b), the outer peripheral surface (7cb) of the main body (7c) of the fuel injector (7) and the outer peripheral surface (10g) of the sleeve (10) are exposed within the engine cooling air path (1b). This diesel engine is characterized by: In the diesel engine according to claim 1 or claim 2 ,
A diesel engine characterized in that the sleeve (10) is a separate part from the cylinder head (1) and is attached to the cylinder head (1). The diesel engine according to any one of claims 1 to 3 ,
A diesel engine characterized in that a pressure surface (12a) of a washer (12) and a pressure receiving surface (10b) of a sleeve (10) are sealed with an adhesive (17). The diesel engine according to any one of claims 1 to 3 ,
A diesel engine characterized in that the space between the pressing surface (12a) of the washer (12) and the pressure receiving surface (10b) of the sleeve (10) is sealed with grease (18). The diesel engine according to any one of claims 1 to 3 ,
A diesel engine characterized in that the space between the pressing surface (12a) of the washer (12) and the pressure receiving surface (10b) of the sleeve (10) is sealed with a sheet gasket (19). The diesel engine according to any one of claims 1 to 6 ,
Concentric circular or spiral grooves (20) extending in the circumferential direction are formed on one or both of the pressure receiving surface (10b) of the sleeve (10) and the pressing surface (12a) of the washer (12). Features a diesel engine. The diesel engine according to any one of claims 1 to 7 ,
A fuel injection hole (9) is provided on the tip surface (7db) of the nozzle part (7d) facing the vortex chamber (2),
A diesel engine characterized in that a part or all of the tip surface (7db) of the nozzle part (7d) protrudes into the vortex chamber (2).

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