JPH0654108B2 - Engine intake system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an engine in which two combustion passages of an engine, that is, two intake passages that are opened and closed by intake valves, that is, two intake ports are opened. Of the intake device.

(Prior Art) In some engines, two combustion passages each opened and closed by an intake valve are opened in one combustion chamber to increase the intake passage area and improve the charging efficiency. is there.

In order to increase the air utilization rate during combustion and minimize the number of fuel injection valves among those having two intake passages for one combustion chamber, for example, Japanese Utility Model Laid-Open No. 60-26284. As disclosed in Japanese Patent Laid-Open No. 2004-242242, there is one in which fuel injected from one injection hole of one fuel injection valve is applied to the branch portions of two intake ports to distribute the fuel to each intake port. Further, for example, as disclosed in Japanese Utility Model Laid-Open No. 59-116570, the fuel from one fuel injection valve having two injection holes corresponding to each intake valve is supplied to each intake passage. There is one that injects and distributes over almost the entire valve face of the intake valve that opens and closes.

(Problems to be Solved by the Invention) By the way, recently, in order to improve the combustibility, particularly to increase the combustion speed as much as possible, an ignition plug is provided almost at the center of the combustion chamber. When such an engine having two intake passages and injecting and distributing fuel from one fuel injection valve to the two intake ports is applied to the engine as described above, Collision fuel is dispersed by the branch part of the intake port,
Since the air in each intake port can be effectively used by the fuel injection from the two injection holes, the overall mixing property of the air and the fuel is improved, but the air-fuel ratio becomes large, that is, lean and the ignitability is improved. Then it becomes unfavorable.

Therefore, an object of the present invention is to distribute and supply the fuel from one fuel injection valve to the valve faces of two intake valves, and in the case where the ignition plug is provided substantially in the center of the combustion chamber. Even if there is, it is an object of the present invention to provide an intake device for an engine that has good ignitability.

(Means and Actions for Solving Problems) In order to achieve the above-mentioned object, in the present invention, basically, fuel injected from one fuel injection valve, that is, 2
The fuel supplied to the combustion chamber through the two intake valves is concentrated as much as possible around the spark plug, that is, near the center of the combustion chamber, so that the air-fuel ratio around the spark plug becomes rich. Specifically, for one combustion chamber of the engine, a first intake passage opened and closed by a first intake valve and a second intake passage opened and closed by a second intake valve are opened, and one fuel injection is performed. In an engine intake system in which fuel from a valve is injected toward the valve faces of the two intake valves, an ignition plug is arranged substantially at the center of the combustion chamber, and the fuel injection valve includes first and second fuel injection valves. The injection path of the first injection hole is to the valve face of the first intake valve, and the injection path of the second injection hole is to the valve face of the second intake valve. On the other hand, the configuration is such that it is set so as to pass radially inward of the combustion chamber with respect to the corresponding valve stems of both intake valves.

As described above, the fuel injected from each injection hole passes radially inward of the combustion chamber with respect to the valve stem of the intake valve. The fuel is supplied in such a manner that it will be concentrated in the center of the combustion chamber as much as possible while being diffused into the air. As a result, the air-fuel ratio around the spark plug becomes rich and the ignitability is improved.

(Embodiment) An embodiment will be described below with reference to the accompanying drawings.

In FIGS. 1 and 2, reference numeral 1 denotes an engine body, which is composed of a cylinder block 2, a cylinder head 3, a cylinder head cover 4, and the like. A piston 6 is provided in each cylinder 5 of the engine body 1. A combustion chamber 7 is formed above the piston 6. In this combustion chamber 7, two first and second intake ports 8 and 9 are provided.
The first and second exhaust ports 10, 10 'are open. Each of the intake ports 8 and 9 is equipped with an intake valve 11 (the intake valve on the side of the second intake port 9 is not shown), and each of the exhaust ports 10 and 10 'is provided with an exhaust valve 12 (the second exhaust port). The exhaust valve on the side of the port 10 'is equipped with (not shown), and these valves are operated by the valve operating mechanism 13 to open and close each port 8, 9, 10, 10' at a predetermined timing. ing. Further, the combustion chamber 7 is equipped with a spark plug 14.

Reference numeral 16 is a surge tank, 17 is an intake pipe for each cylinder connected to the surge tank 16, and outside air is introduced into the surge tank 16 through an air cleaner 18, an air flow meter 15, and a throttle valve 19. ing. The intake pipe 17 is connected to the cylinder head 3 to form an intake passage from the air cleaner 18 to the combustion chamber 7.

A common intake passage 20 extends over a predetermined range between the intake pipe 17 and the cylinder head 3, and the common intake passage 2 is defined by a partition wall 23 in the cylinder head 3.
The downstream end of 0 is branched into first and second branch intake passages 21 and 22.

In the supply / intake passage 20, there are two branch intake passages 21 and 2
A single fuel injection valve 24 is disposed slightly upstream of the partition wall 23 that separates the two from each other. This fuel injection valve 24
Has two first and second injection holes, and an example thereof will be described with reference to FIG.

An oil passage 32 is formed in the body 41 of the fuel injection valve 24, a filter 34 is attached to an inlet 33 of the oil passage 32, and a needle holder 35 is provided downstream of the oil passage 32.
Is tightly fitted. In the needle holder 35, an oil passage 36 communicating with the oil passage 32 of the main body 31, a measuring orifice 37 formed at the downstream end of the oil passage 36, and a seat surface 38 formed immediately upstream of the measuring orifice 37. The needle valve 39 is housed in the oil passage 36. A tapered portion 40 is provided at the tip of the needle valve 39, and the tapered portion 40 and the seat surface 38 constitute a valve body that opens and closes the oil passage 36.

The main body 31 includes an electromagnetic solenoid 41 and a main body 31.
Of the core 42 which is housed in the oil passage 32 of the core and moves to the upstream side by exciting the electromagnetic solenoid 41;
A stopper 43 for restricting the amount of shift of 2 to the upstream side and a return spring 44 for urging the core 42 in the downstream direction are provided, and the upstream end of the needle valve 39 is integrally connected to the core 42. The needle valve 39 is a movable valve body that lifts a certain amount by exciting the electromagnetic solenoid 41 and opens the oil passage 36 by separating the tapered portion 40 from the seat surface 38. In FIG. 3, reference numeral 45 indicates a connector.

The two injection holes 46 and 47 are formed in an outer cylinder 48 fitted onto the needle holder 35. A distribution chamber 49 is provided in the outer cylinder 48 concentrically with the metering orifice 37.
The one injection hole 46, 47 penetrates the outer cylinder 48 from the distribution chamber 49 and opens to the outside.

Therefore, by exciting the electromagnetic solenoid 41, an amount of fuel proportional to this excitation time passes through the metering orifice 31 and is then distributed in the distribution chamber 49 (in the embodiment, it is distributed to the same amount). It will be injected from 46 and 47.

Now, next, intake / exhaust ports 8, 9, 1 for the combustion chamber 7
The arrangement relationship of 0, 10 ', the spark plug 14, the fuel injection valve 24, especially the injection holes 46, 47 will be described.
For convenience of explanation, in FIG. 1, the axis of the cylinder 5, that is, the center of the combustion chamber 7 is set to 0, the cylinder arrangement direction, that is, the center line of the longitudinal direction of the engine is passed through the center 0, and the engine is passed through the center 0. Let l be the axial centerline of.

First, the two intake ports 8 and 9 have substantially equal opening areas, are located closer to the one side surface 1a of the engine body 1 (cylinder head 3) than the center line m, and sandwich the center line 1 from each other. Is formed in position. And
They extend substantially parallel to each other and are connected to the intake pipe 17 on the side surface 1a side. Also, two exhaust ports 1
0 and 10 'have substantially the same opening area,
It is located closer to the other side surface 1b of the engine body 1 than the center line m. Such exhaust ports 10 and 10 'are substantially parallel to each other and are connected to an exhaust pipe (not shown) on the side of the other side surface 1b. And the spark plug 14
(Ignition part) is arranged at the center 0 of the combustion chamber 7 (just the position of the center 0 in the embodiment).

On the other hand, the fuel injection valve 24 is provided with the common intake passage 20 at a position slightly upstream of the partition wall 23 that separates the intake ports 8 and 9 from each other.
It is located on the upper wall of the. Then, the fuel injection valve 24
Is located at a substantially middle portion in the width direction of the common intake passage 20, that is, on the center line 1 (when viewed in FIG. 1). The fuel injection valve 24 arranged as described above has the first injection hole 4
6 is directed toward the valve face of the first intake valve 11 that opens and closes the first intake port 8, and the injection path X ₂ of the second injection hole 47 is the second intake port. Directed to a second valve face that opens and closes port 9.
Further, the fuel diffusion action of both the injection holes 46 and 47 is set to be relatively small, and the injection path X of the first injection hole 46 opens and closes the first intake port 8 as shown in FIG. The intake valve 11 passes through the center 0 side of the valve stem (valve shaft) 11a, in other words, the valve stem 11a and the partition wall 2
It is designed to pass between 3 and. In addition, the second injection hole 47
As shown in FIG. 1, the injection path X ₂ of the injection path X _{2 is} also closer to the center 0 than the valve stem 11′A of the intake valve that opens and closes the second intake port 9, that is, between the valve stem 11′A and the partition wall 23. It is supposed to pass through. The partition wall 23 has a relatively short length, and the injection passages X and X of both the injection holes 46 and 47 are X.
₂ has a length that does not interfere with the partition wall 23.

In the above configuration, the intake air is supplied to the combustion chamber 7 from both intake ports 8 and 9, and the fuel is supplied through both intake ports 8 and 9, so that the mixing property of the fuel and the intake air is increased. Becomes favorable, which is an advantageous combustion condition for improving the air utilization rate, that is, performing complete combustion to obtain an improved output. Further, the fuel is supplied to the vicinity of the center 0, that is, around the spark plug 14 more than at the circumferential branch portion of the combustion chamber 7, so that the air-fuel ratio around the spark plug 14 becomes rich and the ignition is ignited. Will be improved.
Further, since the ignition plug 14 is located substantially in the center of the combustion chamber 7, the combustion speed is also increased, which is preferable for improving the output. Summing up the above points, conditions effective for combustion such as an increase in air utilization rate, an improvement in ignitability, and an increase in combustion speed are complete, which is extremely advantageous in improving output.

FIG. 4 shows another embodiment of the present invention. The same components as those in the above embodiment are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, one exhaust port 10 is provided, and the spark plug 14 is arranged at a position slightly deviated from the center 0 as compared with that of the above embodiment. Since the operation itself of this embodiment is essentially the same as that of the above embodiment, the duplicated description will be omitted.

The fuel injection valve 24 may be a timed injection type that injects fuel according to the intake stroke, or may be a simultaneous injection type that simultaneously injects fuel to all cylinders.

(Effects of the Invention) As is apparent from the above description, the present invention distributes and supplies fuel to two intake valves by one fuel injection valve to improve the air utilization rate while improving the spark plug. Even when the combustion chamber is provided almost at the center, its ignitability can be improved.

In particular, in the present invention, in order to improve the ignitability,
Since the fuel injection valve is of the two injection hole type and the direction of the injection holes need only be set to a predetermined direction, this is extremely advantageous in terms of cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing an embodiment of the present invention. FIG. 2 is a side sectional view of FIG. FIG. 3 is a sectional view showing an example of a fuel injection valve having two injection holes. FIG. 4 shows another embodiment of the present invention and is a plan view corresponding to FIG. 1: Engine body 7: Combustion chamber 8, 9: Intake port 11: Intake valve 11A, 11'A: Valve stem 14: Spark plug 20: Common intake passage 21, 22: Branch intake passage 23: Partition wall 24: Fuel injection Valves 46 and 47: injection holes X 梢, X ₂ : injection path

Claims (1)

[Claims] 1. A fuel injection system in which a first intake passage opened and closed by a first intake valve and a second intake passage opened and closed by a second intake valve are opened to one combustion chamber of an engine. In an engine intake system in which fuel from a valve is injected toward the valve faces of the two intake valves, an ignition plug is arranged substantially at the center of the combustion chamber, and the fuel injection valve includes first and second fuel injection valves. The injection path of the first injection hole is to the valve face of the first intake valve, and the injection path of the second injection hole is to the valve face of the second intake valve. On the other hand, the intake device for the engine is set so as to pass radially inward of the combustion chamber with respect to the corresponding valve stems of the intake valves.