JP3386227B2 - Fuel injection device for reed valve type multi-cylinder two-cycle engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION The present invention relates to a
Fuel injection system for multi-cylinder two-stroke engine
I do. [0002] 2. Description of the Related Art Conventionally, a multi-cylinder two-stroke engine has
There is one configured as follows. That is, a cylinder group composed of a plurality of cylinders
Numbers are provided. In the intake passage provided for each cylinder
Reed valves are provided, and each intake passage of the same cylinder group is
It is merged upstream of the reed valve and
A throttle valve is provided. Each passing through the above intake passage
Fuel injection that supplies fuel to the intake air drawn into the cylinder
A valve is provided. Then, when the engine is driven, a certain cylinder is
The suction process into the crankcase (hereinafter simply referred to as the suction process)
), The reed valve of that cylinder opens,
External air passes through the throttle valve, intake passage, and reed valve
Inhaled into the ink case. [0005] This intake air is reserved in the crankcase.
After being compressed, it is supplied to the combustion chamber in the same cylinder in the scavenging process
Is done. In addition, fuel is injected into this intake,
They are mixed and burned in a combustion chamber. [0006] By the way, in the above-mentioned structure,
In the same cylinder group in a multi-cylinder two-cycle engine
Phase difference so that each reed valve opens at unequal intervals.
In some cases, it is driven as follows.
Problem. [0007] That is, in a certain cylinder group, driving in the earlier phase is performed.
The moving cylinder (hereinafter referred to as the "first cylinder")
The pressure (negative pressure) in the crankcase is the pressure in the intake passage.
When the pressure drops below the force, the reed valve opens and intake air is cranked.
It flows into the case. At this time, the negative pressure of the crankcase
Propagation to the intake passage also causes a negative pressure in the intake passage. In this case, as described above, the same cylinder group
In order to open each reed valve at irregular intervals,
Phase after driving with a short phase difference from "cylinder"
Cylinder (hereinafter referred to as the “later cylinder”) is the suction process
, The intake passage in the intake process of the "first cylinder"
Of the "later cylinder" where this negative pressure remains than the negative pressure of
The negative pressure in the intake passage during the suction process is higher.
You. This phenomenon is caused by an idler with a small throttle valve opening.
This is particularly noticeable at the time of running. As described above, the reed valve is a crankcase.
Of the reed valve
The opening timing of the intake passage is
In the latter cylinder where the negative pressure is high, the top dead center of the
Open timing of the reed valve on the "first cylinder"
A valve opening delay occurs in comparison. For this reason, compared to the "first cylinder"
In all cases, the “rear cylinder” has a larger intake volume (
Air input). Usually, the fuel injection amount is
Determined from the tor opening and the engine speed, the "first cylinder"
And the “later cylinder” have substantially the same fuel injection amount,
The air-fuel ratio (A / F) of the “late cylinder” with a small amount of incoming air is
It becomes larger (darker) than that of the “first cylinder”
This may cause fluctuations in the rotation of the gin. Therefore, the volume of the intake passage must be sufficiently large in advance.
In other words, in the above-mentioned "destination cylinder" suction process,
For the magnitude of the negative pressure in the intake passage and the suction process of the "later cylinder"
Too large difference between the magnitudes of negative pressure in the intake passage
In the first cylinder and the second cylinder.
To make sure that there is no difference in air-fuel ratio between
Conceivable. However, in this case, the intake passage
The problem that the engine becomes large
This is not preferred. [0012] SUMMARY OF THE INVENTION The present invention focuses on the above situation.
The intake air flow of each cylinder in the same cylinder group
Paths are merged with each other upstream of the reed valve of each cylinder.
In a cylinder group with a throttle valve at the junction,
Cylinders open at unequal intervals.
When driven with
By making the amount almost the same to eliminate engine speed fluctuations,
Even if you do this, the engine will not be large
The purpose is to be. [0013] [MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
Of the reed valve type multi-cylinder two-stroke engine of the present invention
The fuel injection device includes a cylinder group 3 including a plurality of cylinders 7 and 8.
5 are provided, and the intake passage 3 provided in each of the cylinders 7 and 8 is provided.
4 is provided with a reed valve 18 for each of the cylinder groups 3 to 5.
The reed valves 18 in the same cylinder group open at irregular intervals
Each of the intake passages 3 to 5 is arranged upstream of the reed valve 18.
The throttle valve 27 is installed at the junction 34a.
KeBy injecting fuel 35 into the intake passage 34Above intake
The intake air 40 is drawn into the cylinders 7 and 8 through the passage 34.
On the other hand, when the fuel injection valve 36 for supplying the fuel 35 is provided,
Here, any one of the plurality of cylinder groups 3 to 5
Reed valve 18 and throttle valve 27 in cylinder groups 3 to 5
Between the intake passage 34 and the other cylinder groups 3 to 5.
The intake passage 34 between the throttle valve 18 and the throttle valve 27
A communication passage 43 for communicating with each other is provided., The fuel injection valve 3
6 directs the fuel 35 toward the valve hole 20 of the reed valve 18.
To be injected into the intake passage 34That
You. [0014] [Operation] The operation of the above configuration is as follows. In FIGS. 1, 2 and 5, for example,
For example, the “earlier cylinder” 7 in the first cylinder group 3
(A in FIG. 5), the intake passage 3 of the first cylinder group 3
When the outside air 39 is sucked through 4
The inside of the intake passage 34 has a negative pressure (part B in FIG. 5). After that, a certain phase from the above "first cylinder" 7
The “later cylinder” 8 driven with a delay (60 °) difference
(C section in FIG. 5)
When the outside air 39 is inhaled (D part in FIG. 5),
Than the negative pressure in the intake passage 34 during the suction process of the cylinder 7
During the suction process of the “later cylinder” 8 where this negative pressure remains,
Of the intake passage 34 to be higher.
You. However, the intake passage 34 of the first cylinder group 3
Are the intake passages 34 of the second cylinder group 4, which is another cylinder group,
A communication passage 43 communicates with the intake passage 34 of the third cylinder group 5.
Have been Therefore, the inside of the intake passage 34 of the first cylinder group 3
When the negative pressure of the intake passage 34 increases, the intake passage 34
The second cylinder group 4 and the third cylinder group through the communication passage 43.
The outside air 39 is sent from each of the intake passages 34 of FIG.
Even during the suction process of the “later cylinder” 8,
The negative pressure of the cylinder is prevented from becoming higher,
7 and the “back cylinder” 8
When the negative pressure in the intake passage 34 at the time of
The magnitudes of the negative pressures of the intake passages 34 in the portions A and C are different from each other.
Is almost the same as Therefore, the “top cylinder” 7 with respect to the top dead center
The opening timing of the reed valve 18 of the “first cylinder” 7 and the “rear cylinder”
Cylinder "8" Reed valve of "Last cylinder" 8 against top dead center
18 is almost the same as the opening timing. On the other hand, the intake passages 34 communicate with each other.
Thus, the substantial capacity of each intake passage 34 is
Although large, the individual intake passages 34 are small in shape.
Will be kept as it is. [0021] Embodiments of the present invention will be described below with reference to the drawings.
You. 1 to 4, reference numeral 1 denotes a multi-cylinder 2
This is a cycle engine. The engine 1 is detachable from the ship 2.
Used as a drive source for an outboard motor attached to a ship
It is. The arrow Fr in the figure is in front of the ship 2 in the traveling direction.
Is shown. The engines 1 are sequentially arranged in a line downward.
The first cylinder group 3 and the second cylinder group which are a plurality of cylinder groups
4 and a third cylinder group 5. In addition, each of these
The cylinder groups 3, 4, and 5 each include two cylinders, each of which has a plurality of cylinders.
Composed of cylinders, one of which is driven in the previous phase
The “first cylinder” 7 and the other cylinders are the “first cylinder” 7
The later cylinder 8 that is driven later with a certain phase difference
You. The engine 1 is provided by a casing 9 covering the engine.
And the casing 9 is attached to the ship 2
Can be The engine 1 is common to each of the cylinder groups 3 to 5.
It has a crankcase 10 and this crankcase 10
Accommodates a vertically oriented crankshaft 11 whose axis is almost vertical.
The crankshaft 11 is opposed to the crankcase 10.
It is rotatably supported around its axis. On the rear surface of the crankcase 10, each cylinder
Each cylinder of “first cylinder” 7 and “back cylinder” 8 of groups 3 to 5
The main body 12 is attached, and these “first cylinders” 7
Each cylinder body 12, 12 of the "later cylinder" 8 is viewed in plan.
Backward from the rear surface of the crankcase 10 so that it becomes V-shaped
It is projected toward. In addition, each of these cylinder bodies 1
The ignition plugs 15 are attached to the protruding ends of
The discharge portion of each ignition plug 15 is
It faces the combustion chamber in the body 12. The front of the crankcase 10
Intake ports for the "cylinder of 7" and "cylinder of the back" 8 respectively
16 are formed, and these intake ports 16 are independent of each other.
ing. Each of these intake ports 16 has a reed valve 1
8 are provided. Each of these reed valves 18 is
Valve Book Removably Attached to Opening Edge of Air Port 16
A body 19 and a plurality of valve holes 20 formed in the valve body 19
And a lead 21 for opening and closing these valve holes 20 freely.
It is configured. On the front face of the valve body 19, each of the cylinder groups 3 to
Air intake manifold 23 common to 5 is detachable
Attached to. This air intake manifold
The valve 23 is a thick plate-shaped manifold attached to the valve body 19.
Hold body 24 and this manifold body 24
And a plurality of six through holes 25 penetrating in the direction.
These through holes 25 are connected to the “first cylinder” 7 and the “back cylinder”.
For each of the "cylinders" 8
I have. The reed valve 18 group for each of the cylinder groups 3 to 5
On the upstream side, that is, the “first cylinder” of each cylinder group 3 to 5
7 and two reed valves 18, 1 corresponding to “later cylinder” 8
8 is provided with a throttle valve 27 on the upstream side.
I have. Each of these throttle valves 27 is
Valve body 28 removably attached to the front of body 24
And a slot provided to traverse the inside of the valve body 28.
Torque shaft 29 and attached to the throttle shaft 29
Each of the cylinder groups 3 to 5 includes a butterfly valve element 30.
Two corresponding to the “first cylinder” 7 and the “back cylinder” 8
At both downstream ends of the through holes 25, 25, the rear end of the valve body 28 is provided.
Inside communicates. Each throttle shaft 2 of the throttle valve 27
9 are connected to each other by interlocking means 31. Soshi
If the operator operates the interlocking means 31,
Each valve element 30 is synchronized with each other via each throttle shaft 29.
The same on-off valve operation is performed. The front end of each valve body 28 has
And a common silencer 33 is detachably mounted
I have. In the above case, the slots communicating with each other
Air intake manifold inside the valve body 28 of the valve 27
23, both through holes 25, both valve bodies 19 of both reed valves 18
Inside and the intake port 16 serve as intake passages 34, respectively.
ing. In this case, each intake passage 3 of the same cylinder group 3 to 5
4 are merged upstream of each reed valve 18,
The throttle valve 27 is provided at the junction 34a.
You. The above-mentioned throttle valve 27 can be easily formed.
To each cylinder group 3-5 individually.
It is provided in an upright shape. The fuel 35 is injected into the intake passage 34.
A fuel injection valve 36 is provided. This fuel injection valve 36
Are provided for each of the reed valves 18 and the slots
The valve 27 is detachably attached to the valve body 28 of the valve 27.
You. In addition, each of the fuel injection valves 36 is supplied from the fuel tank.
A fuel rail 37 capable of supplying the fuel 35 is provided,
The fuel 35 is pressurized and passes through the fuel rail 37.
Then, the fuel is supplied to each fuel injection valve 36. The fuel injection valve 36 is of an electromagnetic type and is electrically operated.
If you turn it on (or off), you will burn
The material 35 is directed toward the valve hole 20 of the reed valve 18 and the intake passage 34
It is to be injected into. When the engine 1 is driven, for example, the first cylinder
When the "first cylinder" 7 of the group 3 is in the suction and compression process,
The throttle valve 27 corresponding to the "first cylinder" 7
The outside air 39 passes through the passage 34 and the reed valve 18 sequentially,
It is sucked into the rank case 10. At this time,
The inside of the passage 34 has a negative pressure.
When the reed 21 of the reed valve 18 is elastically bent, the valve hole 20 is closed.
open. At the time of this inhalation, the
In the intake passage 34, the fuel 3
5 is injected and a mixture 4 of the fuel 35 and the intake air 40 is injected.
1 is sucked into the crankcase 10 and precompressed.
You. This pre-compressed 41 is the subsequent scavenging and explosion process
As described above, the fuel is sucked into the combustion chamber in the “preceding cylinder” 7.
Later, it is burned. In the above case, the "first cylinder" of the first cylinder group 3
7 is the first cylinder, and “the rear cylinder” 8 of the first cylinder group 3 is the
The “first cylinder” 7 of the two-cylinder, second cylinder group 4 is the third cylinder,
The “back cylinder” 8 of the upper second cylinder group 4 is the fourth cylinder, the third cylinder
The “first cylinder” 7 of the group 5 is the fifth cylinder,
If the “later cylinder” 8 is the sixth cylinder,
The sixth cylinder has the same phase difference (crank angle
Of the first cylinder group 3 described above.
Of the cylinder "7"
You. From this, in the same cylinder group 3 to 5,
Is 60 ° from the “first cylinder” 7 to the “back cylinder” 8,
300 degrees from the "back cylinder" 8 to the "front cylinder" 7
Drive at unequal intervals as described above,
Reed valve 18 of cylinder 7 and reed valve 1 of rear cylinder 8
The valve 8 also opens at irregular intervals. In the above configuration, each of the cylinder groups 3 to 5
The reed valve 18 and the slot in one of the cylinder groups
Intake passage 34 between the cylinder group 27 and the other cylinder group.
Intake passage 34 between reed valve 18 and throttle valve 27
A communication passage 43 is provided to communicate the two with each other. With respect to the configuration related to the communication passage 43,
This will be described more specifically. The air intake manifold 23
A groove-shaped first communication passage 44 is formed on the rear surface of the manifold body 24.
And the first communication passage 44 is connected to the “after” of the first cylinder group 3.
The through-hole 25 corresponding to the “cylinder” 8 and the “front end” of the second cylinder group 4
And the through-hole 25 corresponding to the "cylinder 7"
I have. Also, on the rear surface of the manifold body 24
A groove-shaped second communication passage 45 is formed.
Is a through hole 25 corresponding to the “later cylinder” 8 of the second cylinder group 4
And a through-hole 2 corresponding to the “first cylinder” 7 of the third cylinder group 5
5 are communicated with each other. On the other hand, the throttle valve 27 of the first cylinder group 3
The intake passage 34 in the valve body 28 and the second cylinder group 4
The intake passage 34 in the valve body 28 of the rotary valve 27
Connected to each other by an elastic and flexible connecting tube 46
Have been. The inside of the connection tube 46 is a third communication passage 47.
The third communication passage 47 allows the two intake passages
34, 34 are communicated with each other. The throttle valve 2 of the second cylinder group 4
7, the intake passage 34 in the valve body 28, and the third cylinder group 5
Intake passage 34 in the valve body 28 of the throttle valve 27
Is a connecting tube 48 having the same configuration as the connecting tube 46.
Are connected to each other. This connecting tube 48
The inside is a fourth communication passage 49.
Thus, the two intake passages 34, 34 are communicated with each other.
I have. The reason for providing the communication passage 43 will be described in particular in FIG.
This will be described with reference to FIGS. 1, 2, 5, and 6. 5 and 6 show the crank angle on the horizontal axis,
On the vertical axis, the negative pressure of the intake passage 34 and the opening degree of the reed valve 18 are shown.
Is shown. FIG. 5 shows an embodiment of the present invention, and FIG.
In the following, reference numerals A to D in FIG. 5 and A 'in FIG.
To D ′ correspond to each other. In FIGS. 1, 2 and 5, for example,
If the “first cylinder” 7 in the first cylinder group 3 is
(Part A in FIG. 5).
When the outside air 39 is sucked through the passage 34,
Accordingly, the inside of the intake passage 34 becomes negative pressure (part B in FIG. 5). Thereafter, a certain phase from the "first cylinder" 7
The “later cylinder” 8 driven with a delay (60 °) difference
(C section in FIG. 5)
When the outside air 39 is inhaled (D part in FIG. 5),
Than the negative pressure in the intake passage 34 during the suction process of the cylinder 7
During the suction process of the “later cylinder” 8 where this negative pressure remains,
Of the intake passage 34 to be higher.
You. However, the intake passage 34 of the first cylinder group 3
Are the intake passages 34 of the second cylinder group 4, which is another cylinder group,
In the intake passage 34 of the third cylinder group 5, first to fourth communication passages 44,
45, 47, and 49 are communicated by the communication passage 43.
Have been For this reason, the inside of the intake passage 34 of the first cylinder group 3
When the negative pressure of the intake passage 34 increases, the intake passage 34
The second cylinder group 4 and the third cylinder group through the communication passage 43.
The outside air 39 is sent from each of the intake passages 34 of FIG.
Even during the suction process of the “later cylinder” 8,
The negative pressure of the cylinder is prevented from becoming higher,
7 and the “back cylinder” 8
When the negative pressure in the intake passage 34 at the time of
The magnitudes of the negative pressures of the intake passages 34 in the portions A and C are different from each other.
Is almost the same as Therefore, the “first cylinder” 7 with respect to the top dead center
The opening timing of the reed valve 18 of the “first cylinder” 7 and the “rear cylinder”
Cylinder "8" Reed valve of "Last cylinder" 8 against top dead center
18 is almost the same as the opening timing. That is,
Difference in crank angle between open timings of both reed valves 18
(Parts A to C) are the “first cylinder” 7 and the “second cylinder” 8
Approximately the same as the phase difference (60 °)
The intake air amounts in these cylinders 7 and 8 become substantially the same. this
Therefore, the air-fuel ratio of each of the cylinders 7 and 8 becomes substantially the same.
Thus, rotation fluctuation of the engine 1 can be eliminated. In the second cylinder group 4 and the third cylinder group 5,
The relationship between the “first cylinder” 7 and the “back cylinder” 8 is also
This is the same as that shown for the one-cylinder group 3. On the other hand, the intake passages 34 communicate with each other.
Thus, the substantial capacity of each intake passage 34 is large.
However, in terms of shape, the individual intake passages 34 are small.
The engine 1 is large in this way
Is prevented. By the way, in contrast to FIG.
Referring to FIG. 6, the one shown in FIG.
Therefore, the following problem occurs. That is, the “first cylinder” in the first cylinder group 3
7 is the inhalation process (A 'part in FIG. 6).
When outside air 39 is sucked through the intake passage 34 of the cylinder group 3
This suction causes a negative pressure in the intake passage 34.
(Part B 'in FIG. 6). After that, a certain phase from the "first cylinder" 7
The “later cylinder” 8 driven with a delay (60 °) difference
(C 'portion in FIG. 6)
When the outside air 39 is inhaled (D 'part in FIG. 6),
From the negative pressure in the intake passage 34 during the intake process of the cylinder 7
Also, the suction process of the “later cylinder” 8 where this negative pressure remains
If the negative pressure in the intake passage 34 at
I do. That is, the intake air during the intake process of the “first cylinder” 7
The suction pressure of the “later cylinder” 8 is lower than the negative pressure of the passage 34.
The negative pressure in the intake passage 34 at the time of
6 than the negative pressure of the intake passage 34 in the section A ′,
The negative pressure in the intake passage 34 becomes significantly larger. For this reason, with respect to the top dead center of the "preceding cylinder" 7,
Compared to the opening timing of the reed valve 18
8 at the opening timing of the reed valve 18 with respect to the top dead center.
Valve lag (C 'to E') occurs, which is lower than that of the "first cylinder" 7.
In all, the “back cylinder” 8 is the intake air to the crankcase 10
The amount is reduced. As a result, in the above (prior art) section,
As described, the problem of causing engine rotation fluctuation
Is generated. However, as described with reference to FIG.
According to the above, the provision of the communication passage 43 solves the above problem.
Is decided. In FIG. 3, the throttle valve 27 is opened.
The degree is reduced and the engine is idling. This
In the idling state, the intake passage 34
Since the pressure tends to be particularly high,
Thus, the above-mentioned effect is remarkable. In the above case, any of the cylinder groups 3 to 5
Between the downstream end 34b of the junction 34a
An intake passage 34 between the valve body 30 of the rottle valve 27 and
And the downstream end 34b of the merging section 34a in the cylinder groups 3 to 5
Between the valve element 30 of the throttle valve 27 during idling
The third communication passage 47 of the communication passage 43 connects with the intake passage 34.
They are in communication with each other. According to this configuration, the following operation and effect can be obtained. That is, in the intake passage 34 of a certain cylinder group 3 to 5,
Intake air sent from the intake passages 34 of the other cylinder groups 3 to 5
Reference numeral 40 denotes a slot through the third communication passage 47 of the communication passage 43.
Whether it is sent to the junction 34a downstream of the throttle valve 27
The intake air 40 passes through each intake passage 34 more evenly.
It is supplied to each reed valve 18. Therefore, each cylinder 7, 8
In the intake process, each intake passage 3 of the same cylinder group 3 to 5
The magnitude of the negative pressure at 4 is closer to each other,
The amount of intake air to the cylinders 7 and 8 can be further equalized. In FIG. 4, as described above, the first communication passage
44 and the second communication passage 45 are connected to the valve body 19 of the reed valve 18.
And the manifold body of the air intake manifold 23
The groove is formed on the mating surface with the groove 24. others
Therefore, the first communication passage 44 and the second communication passage 45 are bent.
Even if the shape is somewhat complicated, such as
There is an advantage that can be. Although the above description is based on the illustrated example, the engine
1 may be used for automobiles and motorcycles
No. Also, the direction of the engine 1 may be any direction,
For example, the cylinder groups 3 to 5 are arranged in front and rear or left and right.
And each cylinder is located above the crankcase 10.
May be protruded. Further, the communication path 43 is a first communication path.
44 and the second communication passage 45 alone.
In this case, the number of parts of the communication passage 43 can be reduced. Also,
The passage 43 includes only the connection tube 46 and the fourth communication passage 49.
In this case, the throttle valve 27
When individually provided, the respective intake passages 34 communicate with each other.
Easy to make. [0063] According to the present invention, there are provided a plurality of cylinders.
Cylinder groups are provided, and the intake passages
A reed valve is provided for each reed in the same cylinder group.
The valves open at irregular intervals, leading to the intake passages of the same cylinder group.
At the upstream of the valve and throttle at the junction.
Provide a valve,Inject fuel into the intake passageAbove air intake
Supply fuel to intake air that is drawn into each cylinder through the road
Valve type multi-cylinder two-cycle engine equipped with a fuel injection valve
In the gin fuel injection device, the plurality of cylinder groups
Reed valve and throttle valve in any cylinder group
And the reed valve and switch in the other cylinder group.
Communication for communicating the intake passage with the rottle valve to each other
Set up a roadThe fuel is injected into the reed valve by the fuel injection valve.
So that it is injected into the intake passage toward the valve hole.Beat
Therefore, the following effects are obtained. That is, the “first cylinder” in a certain cylinder group is
During the intake process, outside air is passed through the intake passage of the cylinder group.
When inhaling, the suction causes a negative pressure in the intake passage.
become. At this time, a certain phase from the above “first cylinder”
The later cylinder, which is driven later by the difference,
When the outside air is sucked through the upper intake passage,
This negative pressure is higher than the negative pressure in the intake passage during the suction process of the cylinder.
Intake in the “late cylinder” suction process where pressure remains
The negative pressure in the passage tends to be higher. However, the intake passage of the cylinder group described above
Communication with the intake passage of the cylinder group
You. Therefore, the negative pressure in the intake passage of a certain cylinder group
When the air pressure is going to increase,
Outside air is fed from the intake passage of another cylinder group through the passage
Therefore, even during the aforementioned “later cylinder” intake process,
The higher the negative pressure in the road, the lower the pressure
Between the "cylinder" inhalation process and the "later cylinder" inhalation process
The negative pressure in the intake passage at this time becomes substantially the same. Therefore, with respect to the top dead center of the "preceding cylinder"
The opening timing of the reed valve of the "first cylinder" and the "
Opening of the reed valve of the "later cylinder" against the top dead center of the "cylinder"
Is almost the same as the
The volume becomes almost the same. For this reason, the empty
The fuel ratio is almost the same and engine speed fluctuations can be eliminated.
Can be. On the other hand, the above-mentioned intake passages communicate with each other.
Therefore, the substantial capacity of each intake passage increases.
However, in terms of shape, the individual intake passages are kept small
Therefore, when the engine performance is improved as described above
However, the engine is prevented from becoming large.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view taken along line 1-1 of FIG. FIG. 2 is a plan view of the engine. FIG. 3 is a partially enlarged sectional view of FIG. 2; FIG. 4 is a view taken along line 4-4 in FIG. 3; FIG. 5 is a graph showing a relationship between a crank angle, a negative pressure in an intake passage, and an opening degree of a reed valve. FIG. 6 is a graph showing a relationship between a crank angle, a negative pressure in an intake passage, and an opening degree of a reed valve in a conventional example. [Description of Signs] 1 Engine 3 First cylinder group 4 Second cylinder group 5 Third cylinder group 7 “First cylinder” 8 “Rear cylinder” 10 Crankcase 16 Intake port 18 Reed valve 27 Throttle valve 30 Valve element 34 Intake passage 34a Merging portion 34b Downstream end 35 Fuel 36 Fuel injection valve 39 Outside air 40 Intake 41 Air-fuel mixture 43 Communication passage

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI F02M 69/10 F02M 35/10 102G 102K (58) Investigated field (Int.Cl. ⁷ , DB name) F02M 35/10 F02M 69 / 10 F02B 33/30

Claims (1)

(57) [Claims 1] A plurality of cylinder groups each including a plurality of cylinders are provided, and a reed valve is provided in an intake passage provided in each cylinder. opened at irregular intervals, the throttle valve to the merging section provided to the intake passages of the same cylinder group are merged upstream of the reed valve, the intake
The fuel injection system of the injection to the lead valve type multi-cylinder two-stroke engine provided with a fuel injection valve for supplying fuel to the intake air sucked to the intake passage as in each cylinder a fuel in the passage, the plurality Among the cylinder groups, a communication path is provided for communicating an intake passage between a reed valve and a throttle valve in one of the cylinder groups and an intake passage between a reed valve and a throttle valve in another cylinder group with each other , With the above fuel injection valve
Fuel is injected into the intake passage toward the valve hole of the reed valve.
A fuel injection device for a reed valve type multi-cylinder two-cycle engine which is designed to be shot .