JP2022093105A - Electronic fuel injection type diesel engine - Google Patents

Abstract

To provide an electronic fuel injection type diesel engine which can perform precise fuel injection control despite the accumulation of soot on the exit of a fuel injection hole of a fuel injector.SOLUTION: An electronic fuel injection type diesel engine includes a vortex chamber 2, a fuel injector 7 directed to the vortex chamber 2, a communication port led out of the vortex chamber 2, and a main combustion chamber communicated with the vortex chamber 2 via the communication port. On an injector tip surface 8 facing the vortex chamber 2, a fuel injection hole 9 is provided. The fuel injection hole 9 is formed in a flare tapered shape. When the total opening area of an inlet opening 9a of the fuel injection hole 9 of one fuel injector 7 is A square mm and the displacement of one cylinder is C cubic mm, a value of A/C which is obtained by dividing the former value A by the latter value C is 0.5×10-6-1.0×10-6.SELECTED DRAWING: Figure 2

Description

The present invention relates to an electronic fuel injection diesel engine, and more particularly to an electronic fuel injection diesel engine capable of precise fuel injection control regardless of the accumulation of soot at the outlet of the fuel injection hole of the fuel injector.

Conventionally, as an electronic fuel injection diesel engine, it is equipped with a vortex chamber, a fuel injector directed to the vortex chamber, a communication port derived from the vortex chamber, and a main combustion chamber that communicates with the vortex chamber via the communication port. There are some (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2020-67065 (see FIG. 1)

<< Problems >> Soot may reduce the accuracy of fuel injection control.
In the engine of Patent Document 1, when the fuel injection hole of the fuel injector has a single-diameter cylindrical shape, the fuel injection is hindered by a small amount of soot deposit deposited at the outlet of the fuel injection hole, and the fuel injection control is performed by the soot. There is a risk that the accuracy of the fuel will decrease.

An object of the present invention is to provide an electronic fuel injection type diesel engine capable of precise fuel injection control regardless of the accumulation of soot at the outlet of the fuel injection hole of the fuel injector.

The main configurations of the present invention are as follows.
As illustrated in FIG. 1 (A), the vortex chamber (2), the fuel injector (7) directed to the vortex chamber (2), and the communication port (5) derived from the vortex chamber (2). It is provided with a main combustion chamber (4) that communicates with the vortex chamber (2) via the communication port (5).
As illustrated in FIGS. 1 (B), 2 (B), and 3 (B), a fuel injection hole (9) is provided on the injector tip surface (8) facing the vortex chamber (2).
As illustrated in FIGS. 2 (A) and 2 (A), the fuel injection hole (9) has a tapered shape and has a tapered shape.
As illustrated in FIGS. 1B, 2B, and 3B, each fuel injector (7) is provided with a plurality of fuel injection holes (9).
The total opening area of the inlet opening (9a) of the fuel injection hole (9) of one fuel injector (7) exemplified in FIGS. 2 (B) and 3 (B) is defined as A square mm.
With the displacement of one cylinder as C cubic mm,
An electronic fuel injection diesel engine characterized in that the value of A / C obtained by dividing the former value A by the latter value C is 0.5 × 10 ^-6 to 1.0 × 10 ^-6 . ..

The invention of the present application has the following effects.
<< Effect 1 >> Precise fuel injection control can be performed regardless of soot accumulation.
In this engine, as illustrated in FIGS. 2 (A) and 2 (A), the fuel injection hole (9) has a tapered shape, so that even if soot is accumulated at the outlet of the fuel injection hole (9). , Fuel injection is not easily disturbed, and precise fuel injection control can be performed regardless of the accumulation of soot at the outlet of the fuel injection hole (9) of the fuel injector (7).
<< Effect 2 >> Soot is unlikely to be generated in the vortex chamber (2).
As illustrated in FIGS. 1 (B), 2 (B), and 3 (B), since this engine has a plurality of fuel injection holes (9) for each fuel injector (7), FIG. The injection fuel (13) shown in 2 (B) and 3 (B) is widely dispersed in the vortex chamber (2), the mixture of the compressed air and the injection fuel (13) becomes good, and the injection fuel (13) becomes good in the vortex chamber (2). It is hard to generate soot.

<< Effect 3 >> The required output can be obtained, and soot is less likely to be generated in the vortex chamber (2).
In this engine, since the A / C value is set to 0.5 × 10 ^-6 to 1.0 × 10 ^-6 , the following effects can be obtained.
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 required output may not be obtained. .. When the value of A / C 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 ( The oil droplets of the injected fuel (13) do not become fine in 2), the mixture of the compressed air and the injected fuel becomes poor, and soot is likely to be generated in the vortex chamber (2).
On the other hand, when the A / C value is 0.5 × 10 ^-6 to 1.0 × 10 ^-6 , the required output can be obtained and soot is less likely to be generated in the vortex chamber (2). ..

In the figure explaining the electronic fuel injection type diesel engine which concerns on embodiment of this invention, FIG. 1A is a vertical sectional view of a vortex chamber and its peripheral portion, and FIG. An enlarged view of the arrow, FIG. 1 (C) is an enlarged view of the arrow in the C direction of FIG. 1 (A), and FIG. 1 (D) is an enlarged view of the arrow in the D direction of FIG. 1 (A). It is a figure explaining the basic example of the fuel injection hole of the fuel injector used for the engine of FIG. 1, FIG. 2A is a sectional view taken along the line IIA-IIA of FIG. 1A, and FIG. ) Corresponding diagram, FIG. 2 (C) is a corresponding diagram of FIG. 1 (C). It is a figure explaining the deformation example of the fuel injection hole of the fuel injector used for the engine of FIG. 1, FIG. 3 (C) is a diagram corresponding to FIG. 3 (C). It is a figure corresponding to FIG. 2A explaining the first comparative example of the fuel injection hole of a fuel injector. It is a figure corresponding to FIG. 2A explaining the second comparative example of the fuel injection hole of a fuel injector. 6 (A) is a diagram corresponding to FIG. 2 (A), FIG. 6 (B) is a diagram corresponding to FIG. 2 (B), and FIG. 6 (C) is a diagram illustrating a third comparative example of a fuel injection hole of a fuel injector. Is a diagram corresponding to FIG. 2C.

1 to 3 are views for explaining an electronic fuel injection diesel engine according to an embodiment of the present invention, FIG. 1 is an embodiment, FIG. 2 is a basic example of a fuel injection hole used in the embodiment, and FIG. 3 is an embodiment. This is a modification of the fuel injection hole used in.
4 to 6 are views for explaining a comparative example of the fuel injection hole to be compared with a basic example and a modification of the fuel injection hole used in the embodiment of the present invention, FIG. 4 is a first comparative example, and FIG. 5 is a diagram. The second comparative example and FIG. 6 are the third comparative example.

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 in the cylinder (3). It is equipped with.

As shown in FIG. 1 (A), this engine has a vortex chamber (2), a fuel injector (7) directed to the vortex chamber (2), and a communication port (5) derived from the vortex chamber (2). ) And a main combustion chamber (4) communicating with the vortex chamber (2) via the communication port (5).
This engine is a 4-cycle engine. In this engine, compressed air is pushed from the main combustion chamber (4) to the vortex chamber (2) through the communication port (5) near the top dead point of the compression stroke, and the vortex chamber is used. The injected fuel (13) shown in FIG. 2 (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 vortex chamber (2). Is ejected from the communication port (5) shown in FIG. 1 (A) into the main combustion chamber (4), and the unburned fuel contained in the combustion gas is mixed with the air in the main combustion chamber (4) and burned.
The fuel injector (7) is electronically controlled, and a predetermined amount of injection fuel (13) is injected at a predetermined timing.

As shown in FIG. 1A, a piston ring (14a) is externally fitted to the piston (14), and the piston (14) has the cylinder center axis (3a) side as the front side and the cylinder peripheral wall (3b) side as the rear side. ) Is provided with a gas guide groove (14b) that gradually becomes shallower as it approaches the front side.
The vortex chamber (2) is spherical and is formed in the cylinder head (1).
The communication port (5) is formed in a base (15) fitted in the cylinder head (1), and is directed from the main combustion chamber (4) diagonally upward to the vortex chamber (2). The opening (5d) on the main combustion chamber (4) side of the communication port (5) is arranged directly above the rear end portion (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 in the cylinder (3).
A gasket (16) is sandwiched between the cylinder (3), the cylinder head (1), and the base (15).

As shown in FIG. 1 (A), the injector insertion sleeve (10) protrudes diagonally upward from the upper surface (1a) of the cylinder head (1), and the injector insertion sleeve (10) and the cylinder head (1). An injector insertion hole (6) is formed from the protruding end portion (10a) of the injector insertion sleeve (10) to the vortex chamber (2).
As shown in FIG. 1A, the fuel injector (7) has a large-diameter injector main body (7c) and a small-diameter nozzle portion protruding from the injector main body (7c) toward the vortex chamber (2). It is provided with (7d) and a pressing portion (7e) formed in a stepped portion between the injector main body portion (7c) and the nozzle portion (7d).
The fuel injector (7) is inserted into the injector insertion hole (6), and the injector tip surface (8) faces the vortex chamber (2).
The fuel injector (7) is pressed in the insertion direction by the pressing force (11), and the pressing force (11) applied to the fuel injector (7) is applied to the injector insertion sleeve (10) via the pressing portion (7e) and the spacer (12). ) Is received by the protruding end portion (10a).
A gas seal (7f) is externally fitted to the nozzle portion (7d), and the circumference of the nozzle portion (7d) is sealed in the injector insertion hole (6) by this gas seal (7f), which is generated in the vortex chamber (2). The generated combustion gas is prevented from leaking to the outside through the injector insertion hole (6).
An electronic valve mechanism such as an electromagnetic coil is built in the injector main body (7c), and a valve body driven by the electronic valve mechanism is housed in the nozzle (7d).

As shown in FIG. 1 (B), the fuel injector (7) is provided with a fuel injection hole (9) on the injector tip surface (8) facing the vortex chamber (2).
As shown in FIGS. 2 (A) and 2 (A), the fuel injection hole (9) has a widened tapered shape.
As shown in FIG. 1 (A), a part of the injector tip surface (8) protrudes into the vortex chamber (2).
In this engine, the entire injector tip surface (8) may protrude into the vortex chamber (2).

In this engine, as shown in FIGS. 2 (A) and 2 (A), the fuel injection hole (9) has a tapered shape, so that even if soot is accumulated at the outlet of the fuel injection hole (9), Fuel injection is not easily disturbed, and precise fuel injection control can be performed regardless of the accumulation of soot at the outlet of the fuel injection hole (9) of the fuel injector (7).

Further, in this engine, as shown in FIG. 1 (A), a part or all of the injector tip surface (8) protrudes into the vortex chamber (2), and therefore, FIGS. 2 (A) and 3 (A). The combustion gas near the outlet of the fuel injection hole (9) shown in FIG. 1 (A) is easily blown off by the swirling flow (2a) shown in FIG. 1 (A), and soot in the combustion gas grows at the outlet of the fuel injection hole (9). hard.

As shown in FIGS. 1A and 1B, the injector tip surface (8) has a cutting-edge protruding surface (8a) having a fuel injection hole (9) and a flat eddy current guide surface provided around the tip surface (8a). (8b) is provided.
As shown in FIG. 1 (A), a part of the vortex flow guide surface (8b) protrudes into the vortex chamber (2).
In this engine, the entire vortex flow guide surface (8b) may protrude into the vortex chamber (2).

As shown in FIG. 1 (A), in this engine, since at least a part of the vortex flow guide surface (8b) protrudes into the vortex chamber (2), the swirling flow (2) swirls in the vortex chamber (2). 2a) is guided by the vortex guide surface (8b), the swirling flow (2a) swirls smoothly in the vortex chamber (2), the mixture of the compressed air and the injected fuel (13) becomes good, and the vortex chamber (2) ) Is less likely to generate soot.
The most advanced protruding surface (8a) of the injector tip surface (8) is formed in a protruding spherical shape.

As shown in FIGS. 1B, 2B, and 3B, this engine is provided with a plurality of fuel injection holes (9) for each fuel injector (7).
Therefore, the injected fuel (13) shown in FIGS. 2 (B) and 3 (B) is widely dispersed in the vortex chamber (2), the compressed air and the injected fuel (13) are mixed well, and the vortex chamber ( It is difficult for soot to be generated in 2).

As shown in FIGS. 1B, 2B, and 3B, 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 FIG. 1 (B), the total opening area of the six inlet openings (9a) of the fuel injection hole (9) of one fuel injector (7) is A square mm. The amount of fuel for one cylinder is C cubic mm, and the value of A / C obtained by dividing the former value A by the latter value C is 0.75 × ^10-6 . Specifically, the total opening area A of the six inlet openings (9a) of the fuel injection hole (9) was 0.224 square mm, and the displacement C for one cylinder was 299000 cubic mm.
In this engine, it is desirable that the A / C value is 0.5 × 10 ^-6 to 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 required output may not be obtained. .. When the value of A / C 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 ( The oil droplets of the injected fuel (13) do not become fine in 2), the mixture of the compressed air and the injected fuel becomes poor, and soot is likely to be generated in the vortex chamber (2).
On the other hand, when the A / C value is 0.5 × 10 ^-6 to 1.0 × 10 ^-6 , the required output can be obtained and soot is less likely to be generated in the vortex chamber (2). ..

In the basic example of the fuel injection hole (9) shown in FIG. 1 (B), the total opening area of the six outlet openings (9b) of the fuel injection hole (9) of one fuel injector (7) is set to B square mm. 1. The total opening area of 6 inlet openings (9a) of the fuel injection holes (9) of one fuel injector (7) is A square mm, and the former value B is divided by the latter value A. The value was set to 1.26. Specifically, as described above, the total opening area A of the six inlet openings (9a) of the fuel injection hole (9) is 0.224 mm2, and the six outlet openings (9b) of the fuel injection hole (9) are six. The total opening area B of the above was 0.282 mm2.
In this engine, it is desirable that the B / A value is 1.08 to 1.44.

When the value of B / A is less than 1.08, the total opening area B of the outlet opening (9b) is too small with respect 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.
When the B / A value exceeds 1.44, the total opening area B of the outlet opening (9b) is too large for 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 is high at the outlet of the injection hole (9), and a large amount of soot deposits may interfere with fuel injection, resulting in a decrease in the accuracy of fuel injection control.
On the other hand, when the B / A value is 1.08 to 1.44, the fuel injection is not hindered by a small amount of soot deposits, and the soot deposits at the outlet of the fuel injection hole (9). The growth rate of the object is slow, and the accuracy of fuel injection control does not easily decrease.

The reason why the growth rate of soot deposits increases at the outlet of the fuel injection hole (9) when the B / A value exceeds 1.44, whereas the growth rate slows down at 1.44 or less. , Is estimated as follows. That is, in the former, the gap (9) formed around the injected fuel (13) at the outlet of the fuel injection hole (9) becomes excessive, and a large amount of combustion gas containing soot flows into this gap (9). While the soot deposit grows rapidly, in the latter, the gap (9) formed around the injected fuel (1) at the outlet of the fuel injection hole (9) becomes an appropriate size, and the soot deposits. It is presumed that the growth rate of the object and the removal rate of the soot deposit by the injection fuel (13) antagonize each other, and the soot deposit grown at the outlet of the fuel injection hole (9) is immediately removed by the injection fuel. ..

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

In the modified example of the fuel injection hole (9) shown in FIG. 3, as shown in FIG. 3 (C), the vortex chamber side extension line (7b) of the injector central axis (7a) passes through the communication port (5). As shown in FIG. 3B, a plurality (6) fuel injection holes (9) of each fuel injector (7) are arranged around the central axis (7a) of each injector, and FIG. 3C is shown. As shown in the above, a part number (5) of the vortex chamber side extension line (9d) of the injection hole center axis (9c) of the plurality (6) fuel injection holes (9) of each fuel injector (7). Abuts on the peripheral edge (5b) of the vortex chamber side opening (5a) of the communication port (5). The remaining number (1) penetrates the communication port (5).
In this engine, the entire number (6) may abut on the peripheral edge (5b) of the vortex chamber side opening (5a) of the communication port (5).
In this engine, a large amount of injection fuel (13) is injected into the main combustion chamber (4) through the communication port (5), so that excessive combustion in the vortex chamber (2) is prevented and the vortex chamber (2) is prevented. ) Is less likely to generate soot.

As shown in FIG. 3C, in the modified example of the fuel injection hole (9), the front-rear direction orthogonal to each other when viewed in a direction parallel to the vortex chamber side extension line (7b) of the injector central axis (7a). Assuming a vortex chamber side opening (5a) and a similar imaginary line (5c) with each dimension in the lateral direction enlarged by 1.5 times, this similar imaginary line (5c) and the vortex chamber side The peripheral surface of the vortex chamber side opening (5a) where the peripheral surface of the vortex chamber between the opening (5a) and the vortex chamber side extension line (9d) of the injection hole center axis (9c) of the fuel injection hole (9) abuts. It is said to be 5b).
In the modified example of the fuel injection hole (9) shown in FIG. 3, the same elements as the basic example of the fuel injection hole (9) shown in FIG. 2 are designated by the same reference numerals as those in FIG. Unless otherwise specified, the elements of the modified example of the fuel injection hole (9) shown in FIG. 3 have the same structure and function as the elements of the basic example of the fuel injection hole (9) shown in FIG.

When the state of soot generation in the vortex chamber (2) was investigated, the total number of the vortex chamber side extension lines (9d) of the injection hole center axis (9c) of the plurality (6) fuel injection holes (9) ( FIG. 3 shows a basic example of FIG. In the modified example of, the soot in the vortex chamber (2) is compared with the third comparative example of FIG. The amount of soot generated was small.
In the third comparative example shown in FIG. 6, the same elements as the basic example shown in FIG. 2 and the modified example shown in FIG. 3 are designated by adding 100 to the reference numerals of FIGS. 2 and 3. The same applies to the first comparative example shown in FIG. 4 and the second comparative example shown in FIG.

As shown in FIG. 2A, in the basic example of the fuel injection hole (9), the expansion of each injection hole center axis (9c) (or its vortex chamber side extension line (9d)) with respect to the injector center axis (7a). The opening angle (α) is 4 °.
As shown in FIG. 3A, in the modified example of the fuel injection hole (9), the expansion of each injection hole center axis (9c) (or its vortex chamber side extension line (9d)) with respect to the injector center axis (7a). The opening angle (α) is 7 °.
In this engine, it is desirable that the expansion angle (α) of each injection hole center axis (9c) (or its vortex chamber side extension line (9d)) with respect to the injector center axis (7a) is 4 ° to 7 °. ..

When the expansion angle (α) is less than 4 °, some of the plurality of injected fuels (13) are likely to overlap each other, and soot is likely to be generated in the vortex chamber (2).
When the expansion angle (α) exceeds 7 °, most of the injected fuel (13) collides with the inner surface of the vortex chamber (2) without passing through the communication port (5), and enters the vortex chamber (2). Soot is likely to be generated due to excessive combustion in.
On the other hand, when the expansion angle (α) is 4 ° to 7 °, soot is unlikely to be generated in the vortex chamber (2).

When the state of soot generation in the vortex chamber (2) was investigated, in the basic example (Fig. 2) where the expansion angle (α) was 4 ° and the modified example (Fig. 3) where the expansion angle (α) was 7 °, the first of 0 °. Compared with the comparative example (FIG. 4), the second comparative example at 1 ° (FIG. 5), and the third comparative example at 10 ° (FIG. 6), soot was generated less in the vortex chamber (2).

As shown in FIG. 2A, in the basic example of the fuel injection hole (9), the taper angle (β) of each fuel injection hole (9) is set to 12 °.
As shown in FIG. 3A, in the modified example of the fuel injection hole (9), the taper angle (β) of each fuel injection hole (9) is set to 18 °.
In this engine, the taper angle (β) is preferably 12 ° to 18 °.

When the taper angle (β) is less than 12 °, the outlet opening (9b) is too small for the inlet opening (9a) of the fuel injection hole (9), and a small amount deposited at the outlet of the fuel injection hole (9). The soot may interfere with fuel injection and reduce the accuracy of fuel injection control.
When the taper angle (β) exceeds 18 °, the outlet opening (9b) is too large for the inlet opening (9a) of the fuel injection hole (9), and soot is deposited at the outlet of the fuel injection hole (9). The growth rate of objects is high, and a large amount of soot deposits interfere with fuel injection, which may reduce the accuracy of fuel injection control.
On the other hand, when the taper angle (β) is 12 ° to 18 °, a small amount of soot deposits do not interfere with fuel injection, and soot deposits grow at the outlet of the fuel injection hole (9). The speed is slow and the accuracy of fuel injection control does not easily decrease.

When the growth rate of soot deposits at the outlet of the fuel injection hole (9) was investigated, it was 0 in the basic example (Fig. 2) where the taper angle (β) was 12 ° and the modified example (Fig. 3) where the taper angle (β) was 18 °. Soot deposits at the outlet of the fuel injection hole (9) compared to the first comparative example of ° (FIG. 4), the second comparative example of 1 ° (FIG. 5), and the third comparative example of 24 ° (FIG. 6). The growth rate of things was slow.

As in the third comparative example of FIG. 6, 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 growth rate of soot deposits increases in FIG. When the taper angle (β) is 18 ° or less as in the basic example and the modified example of No. 3, the reason why the growth rate becomes slow is presumed as follows. That is, in the former, a relatively large gap (109h) is formed around the injected fuel (113) at the outlet of the fuel injection hole (109), and a large amount of combustion gas containing soot flows into this large gap (109h). While the soot deposit grows rapidly, in the latter, the gap (9h) around the injected fuel (13) becomes an appropriate size at the outlet of the fuel injection hole (9), and the soot deposit grows. It is presumed that the speed and the removal rate of the soot deposit by the injection fuel (13) antagonize each other, and the soot deposit grown at the outlet of the fuel injection hole (9) is immediately removed by the injection fuel.

As shown in FIG. 2A, in the basic example of the fuel injection hole (9), the angle between the injector center axis (7a) and the inner peripheral surface (9g) of each injection hole along the injector center axis (7a). (γ) is 1 °.
As shown in FIG. 3A, in the modified example of the fuel injection hole (9), the angle between the injector center axis (7a) and the inner peripheral surface (9g) of each injection hole along the injector center axis (7a). (γ) is set to 3 °.
In this engine, the narrowing angle (γ) is preferably 1 ° to 3 °.

When the sandwiching angle (γ) is less than 1 °, some of the plurality of injected fuels (13) are likely to overlap each other, and soot is likely to be generated in the vortex chamber (2). When the expansion angle (α) exceeds 3 °, most of the injected fuel (13) collides with the inner surface of the vortex chamber (2) without passing through the communication port (5), and enters the vortex chamber (2). Soot is likely to be generated due to excessive combustion in.
On the other hand, when the sandwiching angle (γ) is 1 ° to 3 °, soot is unlikely to be generated in the vortex chamber (2).

When the state of soot generation in the vortex chamber (2) was investigated, the first comparison of 0 ° was performed in the basic example (Fig. 2) with a pinch angle (γ) of 1 ° and the modified example (Fig. 3) with a pinch angle (γ) of 1 °. The amount of soot generated in the vortex chamber (2) was smaller than that of the example (FIG. 4) and the comparative example of 4 ° (not shown).

As shown in FIG. 2A, 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.
As shown in FIG. 3A, even in the modified 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.

In this engine, the inlet opening edge (9e) of the fuel injection hole (9) is left with a sharp pin angle (9f) that has not been chamfered, so that chamfering is not required, and the fuel injector (7) is manufactured. Will be easier.
Further, in this engine, since the fuel injector (7) injects fuel into the vortex chamber (2), the fuel injection pressure can be lower than that of the direct injection type, and the pin angle (9f) due to the fuel injection pressure can be increased. Wear is unlikely to occur, and the resulting deterioration in fuel injection accuracy is unlikely to occur.

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

(2) ... vortex chamber, (4) ... main combustion chamber, (5) ... communication port, (5a) ... vortex chamber side opening, (5b) ... vortex chamber side opening peripheral edge, (7) ... fuel injector, (7a) ... Injector center axis, (7b) ... Injector center axis extension on the vortex chamber side, (9) ... Fuel injection hole, (9a) ... Inlet opening, (9b) ... Outlet opening, (9c) ... Injection hole Central axis, (9d) ... Extension of the central axis of the injection hole on the vortex chamber side, (9e) ... Inlet opening edge, (9f) ... Pin angle, (9g) ... Inner peripheral surface of the injection hole along the central axis of the injector, (α) ) ... Expansion angle, (β) ... Tapered angle, (γ) ... Narrow angle.

Claims (11)

The vortex chamber (2), the fuel injector (7) directed to the vortex chamber (2), the communication port (5) derived from the vortex chamber (2), and the vortex chamber (5) via the communication port (5). Equipped with a main combustion chamber (4) that communicates with 2)
A fuel injection hole (9) is provided on the injector tip surface (8) facing the vortex chamber (2).
The fuel injection hole (9) has a tapered shape and is provided with a plurality of fuel injection holes (9) for each fuel injector (7).
The total opening area of the inlet opening (9a) of the fuel injection hole (9) of one fuel injector (7) is A square mm.
With the displacement of one cylinder as C cubic mm,
An electronic fuel injection diesel engine characterized in that the value of A / C obtained by dividing the former value A by the latter value C is 0.5 × 10 ^-6 to 1.0 × 10 ^-6 . .. In the electronic fuel injection diesel engine according to claim 1,
The total opening area of the outlet opening (9b) of the fuel injection hole (9) of one fuel injector (7) is set to B square mm.
Let the total opening area of the inlet opening (9a) of the fuel injection hole (9) of one fuel injector (7) be A square mm.
An electronic fuel injection diesel engine characterized in that the value of B / A obtained by dividing the former value B by the latter value A is 1.08 to 1.44. In the electronic fuel injection diesel engine according to claim 1 or 2.
An electronic fuel injection type diesel engine characterized in that 2 to 6 fuel injection holes (9) are provided for each fuel injector (7). In the electronic fuel injection type diesel engine according to any one of claims 1 to 3.
The vortex chamber side extension line (7b) of the injector central axis (7a) passes through the communication port (5), and
A plurality of fuel injection holes (9) are arranged around the injector center axis (7a).
The feature is that all or part of the vortex chamber side extension lines (9d) of the injection hole central axis (9c) of the plurality of fuel injection holes (9) pass through the communication port (5). Electronic fuel injection diesel engine. In the electronic fuel injection type diesel engine according to any one of claims 1 to 3.
The vortex chamber side extension line (7b) of the injector central axis (7a) passes through the communication port (5) and passes through the communication port (5).
A plurality of fuel injection holes (9) of each fuel injector (7) are arranged around the central axis (7a) of each injector.
A part or all of the vortex chamber side extension lines (9d) of the injection hole center axis (9c) of the plurality of fuel injection holes (9) of each fuel injector (7) are on the vortex chamber side of the communication port (5). An electronic fuel-injection diesel engine characterized in that it abuts on the peripheral edge (5b) of the opening (5a). In the electronic fuel injection diesel engine according to claim 5.
When viewed in a direction parallel to the vortex chamber side extension line (7b) of the injector center axis (7a), the vortex chamber side openings (each of which are orthogonal to each other in the anteroposterior direction and the lateral direction are enlarged by 1.5 times, respectively. Assuming 5a) and a similar virtual line (5c), the peripheral surface of the vortex chamber between the similar virtual line (5c) and the vortex chamber side opening (5a) is the center of the injection hole of the fuel injection hole (9). An electronic fuel injection type diesel engine characterized in that the peripheral portion (5b) of the vortex chamber side opening (5a) to which the vortex chamber side extension line (9d) of the axis line (9c) abuts is formed. In the electronic fuel injection type diesel engine according to any one of claims 4 to 6.
An electronic fuel injection diesel engine characterized in that the expansion angle (α) of each injection hole center axis (9c) with respect to the injector center axis (7a) is 4 ° to 7 °. In the electronic fuel injection diesel engine according to any one of claims 4 to 7.
An electronic fuel injection type diesel engine characterized in that the taper angle (β) of each fuel injection hole (9) is 12 ° to 18 °. The electronic fuel injection diesel engine according to any one of claims 4 to 8.
An electron having an angle (γ) between the injector central axis (7a) and the inner peripheral surface (9 g) of each injection hole along the injector central axis (7a) is 1 ° to 3 °. Fuel injection diesel engine. In the electronic fuel injection diesel engine according to any one of claims 1 to 9.
An electronic fuel injection diesel engine characterized in that the inlet opening edge (9e) of the fuel injection hole (9) has a sharp pin angle (9f) that is not chamfered. In the electronic fuel injection diesel engine according to claim 10.
An electronic fuel injection type diesel engine characterized in that the pin angle (9f) is a sharp opening edge having an R of 0.1 mm or less.

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