JP2749108B2 - Fuel injection device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electromagnetic fuel injection valve arranged near an intake port of an internal combustion engine.

[Conventional technology]

A conventional multipoint fuel injection system is disclosed in
As described in Japanese Patent Application Laid-Open Publication No. H10-209, a fuel injection valve for each cylinder is provided on the intake pipe wall of the engine, and fuel is supplied from the fuel injection valve in the direction of the intake valve.

[Problems to be solved by the invention]

The above prior art does not consider the effect of the air flow in the intake pipe on the spray ejected from the fuel injection valve. When the fuel is injected when the intake valve is open during acceleration, high revolution, or the like, the fuel is injected. The spray is bent and cannot be evenly dispersed in the cylinder, the liquid film flows unevenly into the cylinder, the HC emission increases, and the fuel flows only into the oil,
This caused the lubricating oil to be diluted by the fuel.

It is an object of the present invention to uniformly disperse fuel injected from a fuel injection valve in a cylinder, promote evaporation of the fuel, reduce a liquid film in the cylinder, increase HC, and prevent lubricating oil dilution by fuel. Is to do.

[Means for solving the problem]

In order to achieve the above object, the present invention is basically configured as follows.

According to a first aspect of the present invention, in a fuel injection device provided with a fuel injection valve near an intake port of an internal combustion engine, a tubular body protruding into an intake pipe is attached to a tip of the fuel injection valve, and the tubular body is attached to a tip of the tubular body. A fuel collision cylindrical member is provided across the cylindrical body, and the diameter Dt of this cylindrical member and the nozzle diameter of the fuel injection valve
the ratio of d _N, and _{0.5 ≦ Dt / d N ≦ 5} , and characterized by comprising a length lt of the cylindrical member, the ratio of the diameter Dt of the cylindrical member as lt / Dt ≧ 1.0.

According to a second aspect of the present invention, a wedge-shaped member is provided so that the sprayed fuel collides with the tip of the fuel injection valve. A cut surface is arranged so as to face the tip of the fuel injection valve, and a width l ₂ orthogonal to a longitudinal side of a surface opposite to the tip cut surface of the wedge-shaped member and a nozzle diameter d of the fuel injection valve The ratio of _N is l ₂ / d _N ≧ 1.0, and the ratio of the width l ₃ perpendicular to the longitudinal side of the tip cut surface of the wedge-shaped member to the nozzle diameter d _N is 0.5 ≦ l ₃ / d _N ≦ 2.

According to a third aspect of the present invention, a wedge-shaped member is provided so that the sprayed fuel collides with the tip of the fuel injection valve. the ratio of but the arranged to the distal end facing the fuel injection valve, the nozzle diameter d _N of the width l ₂ and the fuel injection valve that is perpendicular to the longitudinal direction of the side of the tip curved surface opposite to the surface of the wedge-shaped member was a l ₂ / d _N ≧ 1.0, and characterized by comprising the relationship between the radius R and the nozzle diameter d _N of the tip curved surface of the wedge-shaped member as _{0.5 ≦ 2R / d N ≦ 2.5} .

[Action]

Operation of the first invention: The fuel injected from the fuel injection valve attached near the intake port passes through the cylindrical body provided at the tip of the fuel injection valve, collides with the collision member, and is atomized. As a result, the injected fuel can be evenly dispersed in the cylinder without being affected by the airflow in the intake pipe even if the fuel is ejected when the intake valve is open, and the fuel is promoted to evaporate. In addition, the liquid film in the cylinder can be reduced, and increase in HC and dilution of lubricating oil by fuel can be prevented. In particular,
The ratio of the above-mentioned ratio of the nozzle diameter d _N of the diameter Dt and the fuel injection valve of the cylindrical member for the fuel collision, and 0.5 ≦ Dt / d _N ≦ 5, and a length lt of the cylindrical member, the diameter Dt of the cylindrical member By setting lt / Dt ≧ 1.0, 200 required to obtain a homogeneous mixture is generally obtained.
Spray formation with a particle size of μm or less has become possible.

Operation of the Second Invention: Fuel injected from the fuel injection valve is:
Two sprays are formed in an arbitrary direction by collision with the wedge-shaped member and by a wedge angle. Further, the injected fuel collides with the cut end surface of the wedge-shaped member, so that the collision between the fuel and the collision member is efficiently performed, and the atomization of the fuel can be achieved. In particular, the results of the test, l ₂ / d _N ≧ 1.0 and the width l ₂ perpendicular to the longitudinal direction of the side ratio of the nozzle diameter d _N of the fuel injection valve of the front end cut surface opposite to the surface of the wedge-shaped member and then, and, by a 0.5 ≦ l ₃ / d _N ≦ 2 the ratio of the width l ₃ and the nozzle diameter d _N perpendicular to the longitudinal direction of the sides of the front end cut surface of the wedge-shaped member, the fuel atomization The particle size can be minimized.

Operation of the third invention: The fuel injected from the fuel injection valve is:
In the same manner as in the second invention, two sprays are formed in an arbitrary direction by colliding with the wedge-shaped member and depending on the wedge angle. In addition, the injected fuel collides with the tip curved surface (radius R surface) of the wedge-shaped member, so that the collision between the fuel and the collision member is efficiently performed, and the fuel can be atomized. In particular, results of the test, the tip curved surface of the wedge member and the width l ₂ perpendicular to the longitudinal direction of the side of the opposite surface the ratio of the nozzle diameter d _N of the fuel injection valve and l ₁ / d _N ≧ 1.0 ,
And, the relationship between the radius R and the nozzle diameter d _N of the tip curved surface of the wedge-shaped member by a _{0.5 ≦ 2R / d N ≦ 2.5} , may work to minimize the particle size of the fuel atomization.

〔Example〕

 FIG. 1 shows an embodiment of the present invention.

Reference numeral 1 denotes an electromagnetic fuel injection valve, which includes a yoke 2, a core 3, an electromagnetic coil 4, a plunger 5, a spring 6, a valve body 7, a nozzle 8, and the like. The plunger 5 and the valve body 7 are integrally connected, and the valve body 7
The tip is urged near the nozzle 8 by the force of the spring 6.

When the electromagnetic coil 4 is energized, a magnetic circuit is formed by the yoke 2, the core 3, the plunger 5, and the like. The plunger 5 is magnetically attracted against the force of the spring 6, and opens.

A hollow cylindrical cover (tubular body) 9 is provided at the tip of the injection valve 1 and the collision member 11 is provided at the tip of the cover 9 so as to cross the cover.
Is provided. The cover 9 is fixed to the injector by caulking or the like. The cover 9 is a gasoline-resistant hollow cylinder made of metal or resin, and has a ventilation hole 10 in a part thereof.

As shown in FIG. 2, the collision member 11 of this embodiment collides and atomizes the fuel in a pin shape (cylindrical member) having a cylindrical cross section. The collision member 11 uses gasoline-resistant metal (such as stainless steel) or resin.

FIG. 3 shows the relationship between the diameter Dt of the collision member 11 and the spray spread angle θ shown in FIG. As the diameter of the collision member 11 increases, the spray spread angle θ can be increased. As shown in FIG. 3, an arbitrary θ can be obtained by changing the diameter.

FIG. 5 shows a change in θ when the fuel pressure is 300 kPa and the distance L between the collision member 11 and the nozzle 8 is changed. When L increases, the fuel velocity when colliding with the collision member 11 decreases due to friction with the air, so that the collision force decreases,
θ decreases.

FIG. 6 shows the relationship between the fuel pressure Pf and θ. As Pf increases, the fuel speed increases, and θ increases.

As described above, the spray spread angle θ can be changed by selecting the diameter Dt of the collision member 11, the distance L between the collision member 11 and the nozzle 8, and the fuel pressure Pf. However, the particle size of the spray varies greatly depending on the above dimensions. Hereinafter, means for forming a spray having a particle diameter of 200 μm or less, which is generally required to obtain a homogeneous mixture, will be described.

FIG. 7 shows the relationship between the diameter D of the collision member 11 and the average spray particle diameter. The nozzle orifice diameter d _N = φ0.7 mm. Dt
Is larger than 0.4 mm and larger than 3 mm. The reason is,
When Dt is 0.4 mm or less, all of the supplied fuel is not atomized by collision and becomes large. Further, when Dt is 3 mm or more, fuel adheres to the collision member, and coarse particles are easily generated.

Shows the relationship between the collision member diameter D and the nozzle diameter d _N in FIG. 8. In order to reduce the particle size, as _{0.5 ≦ Dt / d N ≦ 5} , pick Dt and d _N. Since generally d _N depends on the maximum flow rate of the spray valve, in accordance with the d _N, pick Dt.

FIG. 9 shows the relationship between the ratio of the length lt of the collision member 11 to the diameter Dt of the collision member and the particle diameter d. When lt is small, the fuel that has collided with the collision member easily adheres to the support portion 10a of the collision member, and the particle size increases. In order to obtain a small particle size, lt / Dt ≧ 1.0.

FIG. 10 shows the relationship between the distance L between the collision member 11 and the nozzle 8 and the particle size. When L increases, the fuel velocity at the time of collision with the collision member decreases, so that L tends to increase.
When the fuel pressure Pf is 300 kPa, L is set to 50 mm or less. When Pf is 500 kPa, it should be 60 mm or less.

A small particle size can be obtained by selecting L or Pf such that

FIG. 11 shows another embodiment of the present invention. In this embodiment, the collision member 11 is supported by a support portion 10a protruding from the cover 9.

FIG. 12 shows the relationship between the length 1 of the support portion 10a and the particle size. l
If is small, the fuel that has collided with the collision member 11 rebounds and adheres to the inner wall of the cover 9, and therefore tends to increase. The increase due to the rebound depends on the fuel pressure Pf. To get a small particle size, And When Pf is 300 kPa, for example, l ≧ 2 mm.

FIG. 13 is a cross-sectional view of a different type of injection valve from the above-described embodiment,
FIG. 14 shows an enlarged view of the nozzle portion. Note that in the code,
The same reference numerals as those in the above-described embodiments indicate the same or common elements. For impinging enable collision member fuel jetted from the nozzle, it is necessary to select a nozzle diameter d _N and length L _N.
In this example, although not shown, the collision member is arranged at a distance L from the nozzle 8.

FIG. 15 shows the relationship between the nozzle L _N / d _N and the spray divergence angle θ. Increasing L _N / d _N can decrease θ. This is because the fuel ejected from the nozzle 8 is rectified by the approach section. When the distance L between the nozzle 8 and the collision member is about 70 mm, it is possible to efficiently collide with the collision member by setting L _N / d _N to 3 or more. Further, it is possible to prevent fuel from adhering to the inner wall surface of the cover. When the inner diameter of the cover is large such as φ10mm or more, the length L
Is shorter, L _N / d _N may be 3 or more.

FIG. 16 shows another embodiment of the present invention. By attaching the adapter 12 with the orifice 12a to the tip of the valve element 7 of the pintle type injection valve, a rod-shaped spray can be formed.

FIG. 17 shows the relationship between the cover length L and the spray particle size.
As L increases, the collision speed of the fuel decreases, and the fuel easily adheres to the inner wall of the cover.
Becomes larger.

FIG. 18 shows the relationship between the ratio of the cover length L to the cover long diameter Dc and the particle diameter. When L _N / d _N increases, the fuel tends to adhere to the inner wall of the cover, and the value increases. Nozzle L _N
When / d _N be increased, since the spread of the fuel jet from the nozzle is reduced, the fuel becomes unlikely to adhere to the inner wall.

That is, if L / D _C ≦ 4 or L _N / d _N ≧ 3 is satisfied, the collision between the fuel and the collision member can be effectively performed, and the particle diameter can be reduced.

FIG. 19 shows a technique which triggered another embodiment of the present invention shown in FIG. In this example, the collision member 11 is a member 11-1 having a wedge-shaped cross section, and a holding member for the collision member is provided on the cover 9.
Press in with 11a. When the collision member 11 has a cylindrical shape, depending on the diameter of the cylindrical shape, fuel easily adheres to the collision member 11, and when the amount of fuel ejected from the nozzle is small, the fuel supply becomes discontinuous or coarse. Easy to generate particles. The wedge shape 11-1 can solve the above problem. 2 in any direction depending on wedge angle
Two sprays can be formed. However, compared to the cylindrical shape, the particle size of the spray formed by the atomization by collision when the fuel amount is large is large. This is because the direction of the fuel is largely changed in the cylindrical member due to the collision, and the fuel is easily atomized. Therefore, the following measures were taken.

Figure 20 in a wedge-shaped collision member 11-1 bottom width l ₂ and the nozzle diameter d _N perpendicular to the longitudinal direction of the side of (the tip cut surface of the wedge-shaped member surface opposite) ratio and the particle size Show the relationship. When l ₂ / d _N becomes small, the fuel ejected from the nozzle cannot be atomized by the collision member, and becomes large. In order to reduce the particle size, it is necessary to satisfy l ₂ / d _N ≧ 1.0. Also eliminate fuel metering errors by an opening length l ₄ is the cross-sectional area of the opening 9a is more than twice the orifice cross-sectional area of the fuel nozzle.

Further, as shown in FIGS. 21 and 22, the front end (tapered side) 11 'of the wedge-shaped collision member 11-1 facing the injection port of the fuel injection valve, as shown in FIG. 22 (a). Cut to a plane. A width perpendicular to the longitudinal direction of the sides of the front end cut surface of the wedge-shaped member 11-1 l _3, in the case where the nozzle diameter d _N
FIG. 23 (b) shows the relationship between l ₃ / d _N and the particle size.

By making l / d _N close to 1, it can be reduced.
This is because the collision between the fuel and the collision member is efficiently performed by the flat portion (tip cut surface) 11 '. When l ₃ / d _N is small, the fuel does not completely collide, and when l ₃ / d _N is large, the fuel adheres to the flat portion 11 ′ and becomes large. for that reason,
In order to obtain a small particle size, 0.5 ≦ l ₃ / d _N ≦ 2.

The wedge tip 11 'may be curved as shown in FIG. 22 (b). In this case, if the radius of the curved surface is R, a spray having a small particle diameter can be formed by satisfying 0.5 ≦ 2R / d _N ≦ 2.5.

FIG. 24 shows another embodiment of the present invention. In this example, the cover 9
21 and 22 (a) similar wedge-shaped collision members
In addition to providing 11, an air passage 15 is provided outside the inner cylinder 9-1 of the cover. In the present embodiment, the cover 9 supporting the wedge-shaped member 11 has a double structure, and the cover 9-1 and the cover 9-
An air passage 15 is provided between the air passage 15 and the air passage 15 and air is introduced into the air passage 15 from the throttle valve upstream of the engine intake system.
The air ejected from the outlet 17 is set to collide with the wedge-shaped member 11. Thereby, the fuel that has collided with the collision member 11 can be further atomized by air. In particular, near idle where the pressure difference upstream and downstream of the throttle valve is large,
By increasing the flow velocity of the air flowing through the air passage 15, the atomization of the particle diameter of the spray can be promoted, and the combustion can be improved.

When the engine speed 1000rpm in FIG. 25, when changing the intake pipe pressure P _B, shows the spray particle size. In the case of only collision members, if _PB is small, the fuel amount is small,
Fuel adheres to the collision member and the particle size increases. If only the assist air is, when P _B increases, eliminates the air flow, atomization can not be performed by the assist air.
The larger this reason P _B, the particle diameter increases. By combining the collision member and the assist air to form a spray of small particle size regardless of the P _B. That is, good combustion can be achieved.

FIG. 27 shows an example in which the present invention is applied to an intake port injection engine. In comparison with the conventional example in FIG. 26, in the conventional injection valve, the fuel spray is easy to flow due to the air in the intake pipe, and the particle size is as large as 200 μm. The amount of discharge increases and the amount of fuel attached to the cylinder wall increases. On the other hand, when the cover 9 is provided and the fuel is atomized by the collision member 11 as shown in FIG. 27, the fuel is uniformly dispersed around the intake valve and in the cylinder without being affected by the air flow velocity in the intake pipe. Can be done.

〔The invention's effect〕

According to the present invention, the fuel can be uniformly dispersed in the cylinder, so that the evaporation of the fuel is promoted in the cylinder and the liquid film of the fuel is reduced, so that the HC emission is reduced and the lubricating oil is not diluted by the fuel. Has the effect of doing

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention, FIG. 2 is an explanatory view of the operation of the first embodiment, and FIG. 3 is a relationship between the diameter Dt of the collision member used in the first embodiment and the spray divergence angle. FIG. 4 is an explanatory diagram of the operation when the diameter of the collision member of the first embodiment is changed, FIG. 5 is a diagram showing the relationship between the distance L to the collision member and the nozzle and the spray spread angle θ 6 figure shows the relationship between the fuel pressure Pf and the spray divergence angle theta, Figure 7 Figure showing the relationship between the collision member diameter Dt and the spray average particle diameter, FIG. FIG. 8 is showing the relationship between the Dt / d _N , FIG. 9 is a diagram showing a relationship with lt / Dt, FIG. 10 is a diagram showing a relationship with a cover length L, FIG. 11 is a sectional view showing a second embodiment of the present invention, FIG. FIG. 13 is a view showing the relationship with the support portion length 1 of the second embodiment, FIG. 13 is a sectional view of an injection valve used in a third embodiment of the present invention, and FIG. 14 is a sectional view showing a nozzle part of the third embodiment. Fig. 15 shows the third embodiment. L _N / d _N and θ
FIG. 16 is a sectional view of the injection nozzle portion, FIG. 17 is a diagram showing the relationship with L, FIG. 18 is a diagram showing the relationship with L / Dc, and FIG. Main part sectional view showing 4 Examples,
FIG. 20 is a diagram showing the relationship with l ₂ / d _N , FIG. 21 is an explanatory view of a main part showing a fifth embodiment of the present invention, and FIG. 22 is a cross section showing the shape of the collision member of the fifth embodiment. figures, FIG. FIG. 23 showing the relationship between the magnitude of the collision member, FIG. 24 sixth cross sectional view showing an embodiment of the present invention, FIG. FIG. 25 is showing a relationship between the intake pressure P _B, FIG. 26 is a diagram in which a conventional fuel injection valve is applied to an engine, and FIG. 27 is a diagram in which a fuel injection valve of the present invention is applied to an engine. 1 ... fuel injection valve, 9 ... cover (tubular body), 11 ... collision member, 19 ... air passage, 20 ... intake valve.

Continuation of front page (56) References JP-A-60-113065 (JP, A) JP-A-59-194569 (JP, U) JP-A-60-100569 (JP, U) JP-A-59-45241 (JP) , U)

Claims (7)

(57) [Claims] In a fuel injection device provided with a fuel injection valve near an intake port of an internal combustion engine, a cylindrical body protruding into an intake pipe is attached to a tip of the fuel injection valve, and a cylindrical body is provided at a tip of the cylindrical body. so as to traverse the body is provided a cylindrical member for the fuel collision, the ratio of the nozzle diameter d _N of the fuel injection valve and the diameter Dt of the cylindrical member, and 0.5 ≦ Dt / d _N ≦ 5, and of the cylindrical member A fuel injection device wherein a ratio of a length lt and a diameter Dt of a cylindrical member is lt / Dt ≧ 1.0. 2. The distance L between the collision member from the nozzle tip of the fuel injection valve and the square of the fuel pressure. 2. The fuel injection device according to claim 1, wherein: Wherein the diameter of the nozzle of the fuel injection valve d _N and length L _N
3. The fuel injection device according to claim 1, wherein a ratio of L _N / d _N 3 ≧ 3 is satisfied. Wherein said tubular body inner diameter D _C and comprising the ratio of the length L as L / D _C ≦ 4 claim 1 to a fuel injection system of any one of claims 3 to. 5. A wedge-shaped member is provided so that the injected fuel collides with the front end of the fuel injection valve. surface is disposed so as to face the tip of the fuel injection valve, the nozzle diameter d _N of the width l ₂ and the fuel injection valve that is perpendicular to the longitudinal direction of the sides of the front end cut surface opposite to the surface of the wedge-shaped member The ratio is l ₂ / d _N ≧ 1.0, and the ratio of the width l ₃ orthogonal to the longitudinal side of the cut end face of the wedge-shaped member to the nozzle diameter d _N is 0.5 ≦ l ₃ / d _N ≦ 2. A fuel injection device, characterized in that: 6. A wedge-shaped member is provided so that the injected fuel collides with the tip of the fuel injection valve, and the wedge-shaped member has a tapered tip side having a curved surface with a radius R. is arranged so as to face the tip of the fuel injection valve, the ratio of the nozzle diameter d _N of the width l ₂ and the fuel injection valve that is perpendicular to the longitudinal direction of the side of the tip curved surface opposite to the surface of the wedge-shaped member and l ₂ / d _N ≧ 1.0, and a fuel injection apparatus characterized by comprising a relationship between the radius R and the nozzle diameter d _N of the tip curved surface of the wedge-shaped member as _{0.5 ≦ 2R / d N ≦ 2.5} . 7. A member for supporting the wedge-shaped member is provided with a passage through which air introduced from an upstream of a throttle valve of an engine intake system is jetted toward the wedge-shaped member. 7. The fuel injection device according to claim 5, wherein the fuel injection device is set to collide with a wedge-shaped member.