JPH10103196A - Multi-intake valve type engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impede sticking of fuel to a cylinder internal wall while adopting a constitution injecting fuel in an intake passage. SOLUTION: An intake passage is constituted by a swirl forming passage 8b and a fuel supplying passage 8c having an opening/closing passage 24 in the upstream and a fuel injection passage 17 in the downstream. The fuel injection device 17 is formed into a constitution making fuel flow into almost the center of a combustion chamber by pressure air. The opening/closing valve 24 is constituted to be closed when an engine operating region is in a low load low speed operating region and opened when in the other operating region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiple intake valve type engine for supplying fuel to the center of a combustion chamber of each cylinder.

[0002]

2. Description of the Related Art Among harmful components in engine exhaust gas,
In many cases, HC is discharged from an exhaust port in a state where fuel attached to an inner wall of a cylinder is not burned. That is,
The fuel that has flowed into the cylinder from the intake port together with the intake air adheres to the cylinder by colliding with the cylinder inner wall on the opposite side to the intake port, and is discharged from the exhaust port opened above the attachment portion during the exhaust stroke. Conventionally, a structure such as injecting fuel toward the center of the combustion chamber by a fuel injection device is employed to prevent the fuel from adhering to the inner wall of the cylinder as much as possible.

[0003]

However, in the structure in which fuel is injected into the intake passage, the fuel is blown into the cylinder together with the intake air flow during the intake stroke. Therefore, the fuel is injected into the cylinder only by adjusting the direction of fuel injection. It could not be prevented from sticking to the inner wall. In particular, when the engine operating range is in the low-load low-speed operating range, the flow rate of intake air is slow, and fuel easily adheres to the inner wall of the cylinder, so that the amount of HC emission increases.

The present invention has been made in order to solve such a problem, and has a multi-intake valve type which can prevent fuel from adhering to the inner wall of a cylinder while adopting a structure for injecting fuel into an intake passage. The purpose is to provide an engine.

[0005]

SUMMARY OF THE INVENTION In a multiple intake valve type engine according to the present invention, a plurality of intake passages communicating with one combustion chamber form a swirl flow around a cylinder axis. A swirl forming passage, and a fuel supply passage having a fuel injection means and having a flow of intake air controlled by an intake pause means, wherein the fuel injection device injects fuel when the intake valve is open. And spraying the fuel injected from the fuel injection port of the fuel injection device main body with the pressurized air toward the cylinder center side and the upstream side of the intake passage from the stem as viewed from above the cylinder on the upper surface of the valve body of the intake valve. Thereby, the structure is made to flow into substantially the center of the combustion chamber, and the intake pause means stops the flow of intake air in the fuel supply passage when the engine operation range is in the low load low speed operation range, In which the intake to the fuel supply passage is configured to flow when in the operating range.

According to the present invention, when the engine operating range is in the low-load low-speed operating range, the intake from the fuel supply passage is stopped, and the intake air flows into the cylinder only from the swirl forming passage and enters the cylinder. A swirl consisting of the intake flow is generated. When the fuel strikes the valve element of the intake valve, the flow direction is changed to a direction toward the center of the combustion chamber, and the flow velocity is reduced. The fuel is supplied to the substantially center of the combustion chamber (the center of the swirl) together with the compressed air. That is, when the engine operating range is in the low-load low-speed operating range, the fuel is supplied to the inside of the air wall formed in the cylinder.

A multi-intake valve engine according to another invention is the multi-intake valve engine according to the invention described above, wherein the intake pause means is constituted by an on-off valve provided upstream of the fuel injection device in the fuel supply passage. It was done. According to the present invention, the configuration for stopping the flow of intake air in the fuel supply passage may be simple.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. FIG. 1 is a sectional view of an upper portion of a cylinder of a multi-intake valve engine according to the present invention, FIG.
FIG. 3 is an enlarged sectional view showing a fuel injection device mounting portion. FIG. 4 is a configuration diagram for explaining the direction of fuel injection, and FIG. 5 is a perspective view of the same.

In these figures, reference numeral 1 denotes a multi-intake valve type multi-cylinder engine according to this embodiment, 2 denotes a cylinder body of the engine 1, 3 denotes a cylinder head, 4
Denotes a head cover, 5 denotes a piston, 6 denotes a combustion chamber, and 7 denotes a spark plug. The spark plug 7 is disposed on the cylinder axis.

As shown in FIG. 2, the cylinder head 3 has two intake ports 8 for each cylinder and an exhaust port 9 formed in a bifurcated shape, and has two intake ports 8a, 8a and exhaust ports 9a, 9a with the intake valves 10, 10 and the exhaust valves 11,
It is configured to open and close at 11. The intake ports 8, 8 are formed so as to be symmetrical in the left-right direction in FIG. 2 and their axes are parallel to each other in plan view shown in FIG.

The intake valve 10 and the exhaust valve 11 are configured to be driven by a valve operating mechanism 12 having a conventionally known structure. Reference numeral 13 denotes a valve lifter of the valve mechanism 12, 1
4 is a valve spring (see FIG. 3), 15 is an intake camshaft, and 16 is an exhaust camshaft. In FIG. 1, the valve spring 14 is omitted.

In the cylinder head 3, a fuel injection device 17 is mounted on one upper side of two intake ports 8 provided for each cylinder, and an intake manifold 18 is mounted on an upstream end of both intake ports 8, and exhaust gas is exhausted. An exhaust manifold 19 is attached to the downstream end of the port 9. The intake passage 8b of the intake port 8 having the fuel injection device 17 of the two intake ports 8, 8 constitutes a fuel supply passage according to the present invention, and the intake passage 8c of the other intake port 8 according to the present invention. The swirl forming passage is configured. Further, the exhaust manifold 19 is provided with a 0 ₂ sensor 21, a catalyst 2
An exhaust pipe (not shown) having 2 is attached to the downstream end.

The intake manifold 18 comprises an intake pipe 18a for each cylinder and a surge tank 18b, and a throttle valve 20 is provided at one end of the surge tank 18b.
The intake pipe 18a is formed in a bifurcated form by branching an internal intake passage in the middle so that the downstream end communicates with the two intake ports 8 of each cylinder.
A butterfly-shaped opening / closing valve 24 is interposed in an intake passage 23 communicating with the valve. This on-off valve 24 constitutes the intake pause means according to the present invention.

The on-off valve 24 is mounted on an operating shaft 25 passing through the intake pipe 18a, and is configured to operate a driving device 26 connected to one end of the operating shaft 25. The driving device 26 is configured to close the on-off valve 24 when the operating range of the engine 1 is in the low-load low-speed operating range, and to open the on-off valve 24 when the engine 1 is in another operating range.

As shown in FIG. 3, the fuel injection device 17 includes an injection fuel passage forming member 27 fitted and fixed to the cylinder head 3, and a fuel injection device main body 28 fixed to the injection fuel passage formation member 27. It is composed of When the intake valve 10 is open, the fuel injection device main body 28 feeds fuel pumped from a fuel supply source (not shown).
The nozzle portion 28a is ejected from the center of the tip end of the injection fuel passage forming member 27.
7a. A seal 29 is interposed between the base of the nozzle portion 28a and the wall surface of the nozzle hole 27a. Also, a seal 30 is interposed between the injection fuel passage forming member 27 and the cylinder head 3.

The nozzle hole 27a has a structure in which a gap is formed between the tip of the nozzle portion 28a and the wall surface of the hole. This gap is indicated by the symbol S in FIG. This gap S
Is an annular groove 27 formed on the hole wall surface of the nozzle hole 27a.
b, a communication hole 27c extending from the annular groove 27b, and an air hole 31 formed in the cylinder head 3 to open to the atmosphere.

The injection fuel passage forming member 27 has an injection fuel passage 32 for guiding the fuel injected from the fuel injection device main body 28 to the intake passage 8 b in the intake port 8. An air passage 33 for supplying compressed air is formed. The injection fuel passage 32 is
The upstream end is the center of the tip of the fuel injection device main body 28 on the inner bottom surface of the nozzle hole 27a, that is, the nozzle portion 28
a is opened at a portion facing a fuel injection port (not shown),
The downstream end indicated by reference numeral 32c in FIG. In the fuel injection device 17, the opening at the downstream end 32c of the injection fuel passage 32 forms a fuel injection port.

The injection fuel passage 32 is formed so as to be bent in a crankshaft shape in the injection fuel passage forming member 27, and the downstream portion 3a is opposed to the upstream portion 32a upstream of the bent portion.
2b is unevenly distributed on the cylinder axis side. This downstream part 3
2b is formed in a straight line, and the axis C is directed to the center of the cylinder (the center of the combustion chamber) in the plan view shown in FIGS. 2 and 4 and to the valve body 10a of the intake valve 10 in the side view shown in FIG. It is composed. More specifically, the fuel injection device 17 includes an injection point A (see FIGS. 4 and 5) on the cylinder center side and the upstream side of the intake passage from the stem 10b when viewed from above the cylinder on the upper surface of the valve body 10a of the intake valve 10. Are provided so as to be oriented.

The air passage 33 is connected to the injection fuel passage 3.
The downstream end communicates with the upstream end of the linearly formed downstream portion 32b in FIG. In this embodiment, the portion of the air passage 33 communicating with the downstream portion 32b (the communicating portion is indicated by reference numeral 33a in FIG. 3) is formed such that the cross-sectional area of the passage is smaller than that of the other portions in this embodiment. The structure is such that it substantially coincides with the axis C. That is,
The communication portion 33a of the air passage 33 has an axis line of the intake port 8a.
It is formed so as to be directed in the direction.

The upstream end of the air passage 33 is connected to a compressor (not shown) through a pressurized air passage 34 formed in the cylinder head 3 and an air pipe (not shown) connected to the cylinder head 3. Of the pressurized air supply source. The pressurized air of the pressurized air supply source passes through the pressurized air system, and the flow velocity is increased in the communication portion 33 a of the air passage 33, and is blown out to the downstream portion 32 b of the injection fuel passage 32.

The multiple intake valve type engine 1 constructed as described above
Is the on-off valve 2 when the operating range is in the low-load low-speed operating range.
4 is closed, and the intake port 8 of the two intake ports 8, 8 in which the fuel injection device 17 is not present is located in the cylinder.
Only the intake air is supplied. For this reason, at this time, as shown by an arrow in FIG. 2, the intake air turns around the cylinder axis in the cylinder, and a swirl composed of a swirling flow of the intake air is generated in the cylinder.

On the other hand, fuel is injected from the fuel injection device main body 28 into the injection fuel passage 32 when the intake valve 10 is open, and from the upstream portion 32a of the injection fuel passage 32 through the bent portion to the downstream portion. 32b. The fuel is blown at the upstream end of the downstream portion 32b with pressurized air to form fine particles, and is blown off by the pressurized air to form the downstream portion 32b.
It is injected in the axial direction of b. As a result, the fuel and the high-pressure air having the fine particles are injected from the downstream end 32c of the injection fuel passage 32 toward the intake port along the axis C. The range in which the fuel is injected is shown by a two-dot chain line in FIG. That is,
Intake passage 8b of intake port 8 having fuel injection device 17
The fuel is supplied to the combustion chamber 6 along with the flow of the pressurized air even when the intake air flow is not generated.

The fuel injection device 17 has a fuel injection direction of the axis C.
In this case, the fuel injected from the fuel injection device 17 at this time is blown to the vicinity including the injection point A on the upper surface of the valve body of the intake valve 10. For this reason, the fuel injected from the fuel injection device 17 hits the valve element 10 a of the intake valve 10, whereby the flowing direction is changed to a direction toward the center of the combustion chamber 6 and the flow velocity is reduced.

Therefore, when the engine operating range is in the low-load low-speed operating range, the fuel is supplied at a low speed to the substantially center (the center of the swirl) of the combustion chamber 6 together with the compressed air. That is, the fuel is supplied inside the air wall formed in the cylinder in the cylinder, and does not contact the cylinder inner wall.

When the engine operating range shifts from the low-load low-speed operating range to the high-load high-speed range, the on-off valve 24 is opened, so that intake air flows into the cylinder from both intake ports 8,8. At this time, the fuel is supplied to the combustion chamber 6 together with the intake air flowing through the intake passage 8b and the compressed air. When the fuel flows into the combustion chamber 6, the valve 1 of the intake valve 10
The flow direction resulting from hitting 0a is changed to a direction pointing toward the center of the combustion chamber 6, and the flow velocity decreases.

Therefore, even if an intake air flow occurs in the intake port 8 having the fuel injection device 17, the fuel stays at the center of the combustion chamber 6. That is, fuel does not adhere to the cylinder inner wall over the entire engine operating range.

Second Embodiment A fuel injection device may be configured as shown in FIG. FIG. 6 is a plan view showing another embodiment of the fuel injection device. In FIG. 6, the same reference numerals are given to the same or equivalent members as those described in FIG. 1 to FIG. 5, and detailed description is omitted. .

The fuel injection device 17 shown in FIG. 6A has a fuel injection device main body 28 and an injection fuel passage forming member 29.
The axes of (a downstream portion of the injection fuel passage not shown) are inclined with respect to the intake port 8 in a plan view, and the direction of the fuel injection is directed to the injection point A of the intake valve 10.

The fuel injection device 17 shown in FIG. 6B has a fuel injection device main body 28 and an injection fuel passage forming member 29.
The axis of (the downstream portion of the injection fuel passage not shown) is parallel to the intake port 8 in plan view, and the fuel injection direction is directed to the injection point A of the intake valve 10. For this reason, in this embodiment, the fuel injection device 1
7 is unevenly distributed on the other intake port 8 side. 6A and 6B, even if it is configured as shown in FIGS.
The same effect as when adopting the form shown in FIG. 5 is obtained.

Third Embodiment The fuel injection device can be further configured as shown in FIG. FIG. 7 is a cross-sectional view showing another embodiment of the fuel injection device. In FIG. 7, the same or equivalent members as those described in FIGS. 1 to 5 are denoted by the same reference numerals, and detailed description is omitted. .

The fuel injection device 17 shown in FIG. 7 is disposed below the intake port 8 in the cylinder head 3, and the tip of the injection fuel passage forming member 27 faces the intake passage 8b from below. For this reason, the fuel injection device main body 28 projects obliquely downward from the side of the cylinder head 3. The injection fuel passage 32 of the injection fuel passage forming member 27 has a cross section L such that the upstream portion 32a extends on the same axis as the fuel injection device main body 28 and the downstream portion 32b extends in a direction substantially perpendicular to the upstream portion 32a. It is formed in the shape of a letter. The axis C of the downstream portion 32b is directed to the center of the cylinder (the center of the combustion chamber) in plan view when the cylinder head 3 is viewed from above, and is directed to the valve body 10a of the intake valve 10 in side view shown in FIG. Make up.

When the fuel injection device 17 is configured as described above, the fuel injection device main body 28 can be disposed in a wide space beside the cylinder body 2, so that interference between the fuel injection device main body 28 and other members is prevented. The fuel injection port (downstream end 32 c of the injection fuel passage 32) can be made closer to the combustion chamber 6 while avoiding.

In each of the above-described embodiments, an example has been shown in which the on-off valve 24 provided in the fuel supply passage (intake passage 8b) constitutes the intake stop means. The intake valve 10 that opens and closes the valve 8b may be constituted by a valve pause device that keeps the intake valve 10 in a fully closed state.

[0034]

As described above, in the multi-intake valve engine according to the present invention, the multiple intake passages communicating with one combustion chamber are changed to a swirl flow in which the intake air flow in the cylinder is centered on the cylinder axis. A swirl-forming passage, and a fuel supply passage having a fuel injection means and having a flow of intake air controlled by an intake pause means, wherein the fuel injection device supplies fuel when the intake valve is open. In addition to the injection structure, the fuel injected from the fuel injection port of the fuel injection device body is blown by pressurized air to the cylinder center side and the upstream side of the intake passage from the stem in the cylinder top view on the upper surface of the valve body of the intake valve. Thereby, the structure is such that the air flows into substantially the center of the combustion chamber, and the intake pause means stops the flow of the intake air in the fuel supply passage when the engine operation region is in the low-load low-speed operation region. When the engine is in the low-load, low-speed operation range, the intake from the fuel supply passage is stopped, and only the swirl-forming passage is provided. Then, the intake air flows into the cylinder, and a swirl composed of the intake air flow is generated in the cylinder. The fuel strikes the valve body of the intake valve,
The flowing direction is changed to a direction pointing toward the center of the combustion chamber, and the flow velocity is reduced.

Therefore, when the engine operating range is in the low-load low-speed operating range, the fuel is supplied to the inside of the cylindrical air wall formed in the cylinder and does not contact the cylinder inner wall. Therefore, all the fuel is burned, and the emission amount of the HC component can be reduced. Even if the engine operating area shifts to the high-load high-speed operating area side and the intake air flow also occurs in the fuel supply passage, the fuel stays in the center of the combustion chamber, so the entire engine operating area The fuel does not adhere to the inner wall of the cylinder, and the emission amount of the HC component can be suppressed low.

A multi-intake valve engine according to another aspect of the present invention is the multi-intake valve engine according to the above-described invention, wherein the intake pause means is constituted by an on-off valve provided upstream of the fuel injection device in the fuel supply passage. Therefore, the configuration for stopping the flow of the intake air in the fuel supply passage may be simple. Therefore, it is possible to suppress an increase in cost in carrying out the present invention as low as possible.

[Brief description of the drawings]

FIG. 1 is a sectional view of an upper portion of a cylinder of a multiple intake valve engine according to the present invention.

FIG. 2 is a plan view of an upper portion of a cylinder of the multi-intake valve engine according to the present invention.

FIG. 3 is an enlarged sectional view showing a fuel injection device mounting portion.

FIG. 4 is a configuration diagram for explaining a direction of fuel injection.

FIG. 5 is a perspective view for explaining the direction of fuel injection.

FIG. 6 is a plan view showing another embodiment of the fuel injection device.

FIG. 7 is a sectional view showing another embodiment of the fuel injection device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 3 ... Cylinder head, 6 ... Combustion chamber, 7 ...
Spark plug, 8: intake port, 8a: intake port, 8b, 8
c ... intake passage, 10 ... intake valve, 10a ... valve body, 10b ...
Stem, 17: fuel injection device, 24: on-off valve, 27: injection fuel passage forming member, 28: fuel injection device main body, 32 ...
Injected fuel passage 33, air passage.

────────────────────────────────────────────────── ─── front page continued (51) Int.Cl. ⁶ identifications FI F02D 9/02 361 F02D 43/00 301D 43/00 301 301U 45/00 312J 45/00 312 F02M 69/04 G F02M 69/04 P 69/08 69/08 69/00 350P 350W

Claims (2)

[Claims] In a multiple intake valve type engine in which a plurality of intake passages communicate with one combustion chamber, the intake air flowing into the cylinder becomes a swirling flow about a cylinder axis in the plurality of intake passages. A swirl forming passage, and a fuel supply passage having a fuel injection means and having a flow of intake air controlled by an intake pause means, wherein the fuel injection device injects fuel when the intake valve is open. And spraying the fuel injected from the fuel injection port of the fuel injection device main body with the pressurized air toward the cylinder center side and the upstream side of the intake passage from the stem as viewed from above the cylinder on the upper surface of the valve body of the intake valve. With this structure, the intake air flow is made to flow into substantially the center of the combustion chamber, and the intake pause means stops the flow of intake air in the fuel supply passage when the engine operation range is in the low-load low-speed operation range. A multi-intake valve type engine wherein the intake air flows through a fuel supply passage when the engine is in another operating range. 2. The multi-intake valve type engine according to claim 1, wherein the intake pause means is constituted by an on-off valve provided on the fuel supply passage on the upstream side of the fuel injection device. engine.