JP2003095176A - In-take system component configuration for fuel injection engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a component configuration for configuring in-take system components in an efficient space for a swing unit type fuel injection engine with a suction piston mounted on a throttle body rocking together with the engine. SOLUTION: The in-take system for the fuel injection engine comprises the engine 29 rockingly mounted on a body frame 34 together with a rear wheel, the throttle body 48 provided on an in-take passage at the rear upper part of a rocking center 31 of the engine, and a suction piston 51 mounted protruding on the upper side of the throttle body, wherein an injector 50 and a suction pressure sensor 57 are provided on the throttle body 48 or in the in-take passages 39, 40 in a range up to the height of the top of the suction piston 51.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a component arrangement structure in an intake system of a fuel injection engine.

[0002]

2. Description of the Related Art In a small motorcycle such as a scooter,
A swing unit type engine is used. In this swing unit engine, an engine unit is formed by integrally connecting an engine crankcase and a speed reducer case, a rear wheel is connected to the speed reducer, and a swing unit is attached to a vehicle body frame through a damper so that the engine unit The front part of the is pivotally attached to the vehicle body frame via a pivot. As a result, the engine unit can rotate together with the rear wheels within an angular range centered on the pivot, and swings with respect to the vehicle body frame to absorb vibration during traveling.

As a swing unit type engine for such a small motorcycle, a two-cycle engine equipped with a carburetor has been used in the past, but a fuel injection type engine has been used for high precision operation controllability and improvement of exhaust gas emission. The use of a 4-cycle engine is considered and is under development. Since the injection control and the ignition control are performed according to the operating state of such a fuel injection engine, the cooling water temperature, the intake air temperature, the intake negative pressure, etc. are detected, and these detection signals are sent to the engine control device (E
CU). The ECU controls the drive of the engine according to a predetermined program or map based on these operating state detection signals.

On the other hand, in an automobile engine equipped with a carburetor, there is known an intake system structure having a suction piston in an intake passage between the carburetor and the air cleaner. This suction piston moves forward and backward in the intake passage based on the negative pressure of the intake air to change the passage cross-sectional area, thereby controlling the intake air amount, obtaining optimum engine performance according to the operating state, and passing through the intake passage. This is to prevent sound leakage to the outside.

This suction piston is composed of a diaphragm chamber composed of a first chamber and a second chamber which are partitioned by a diaphragm, and a piston which moves back and forth in the intake passage in conjunction with the diaphragm chamber. The first chamber on one side of the diaphragm communicates with the intake passage through the opening at the tip of the piston inserted into the intake passage. Since the area of the intake passage is reduced by the piston, the piston tip portion and the downstream side thereof are in a large intake negative pressure state. Therefore,
Intake negative pressure acts on the first chamber through the inside of the piston.

On the other hand, the second chamber on the other side of the diaphragm communicates with the intake passage upstream of the piston via the communication passage. The intake passage on the upstream side of the piston is connected to the air cleaner and is in a substantially atmospheric pressure state. Therefore, substantially atmospheric pressure acts on the second chamber via the communication passage. As a result, a pressure difference is generated on both sides of the diaphragm, and the diaphragm is deformed by this pressure difference, and the piston moves forward and backward in the intake passage.

On the other hand, in the fuel injection engine, a throttle body having a throttle valve is connected in the middle of the intake passage, and the intake air amount is controlled by opening / closing the throttle valve. In such a fuel injection engine, the fuel injection control can be performed with high accuracy according to the operating state by electronic control, and the operating performance and exhaust gas emission countermeasures can be sufficiently secured. It has never been used before.

However, in the fuel injection engine, it is required to further finely control the fuel in a wide control range according to the operating condition to further improve the operating performance and the exhaust gas emission.

In response to such a demand, it has been considered to provide a suction piston in the intake system like the carburetor. In this case, in the swing unit type engine, the throttle body swings together with the engine. A suction piston having a relatively large shape is attached to the throttle body, and when the suction piston swings, the arrangement of parts in the swinging range is restricted. Particularly in motorcycles, there is a large space limitation around the engine, and it is necessary to compactly arrange the injector, the intake pressure sensor, and the like provided in the intake system together with the suction piston.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above points, and in a swing unit type fuel injection engine in which a suction piston is attached to a throttle body that swings together with the engine, the intake system parts are provided in a space. It is an object of the present invention to provide a component arrangement structure of an intake system of a fuel injection engine that is efficiently disposed.

[0011]

In order to achieve the above object, according to the present invention, an engine is swingably attached to a vehicle body frame together with a rear wheel, and a throttle body is provided on an intake passage above a swing center of the engine. In an intake system of a fuel injection engine having a suction piston attached so as to project above the throttle body, an injector and an intake pressure sensor are provided in the throttle body or the intake passage in a range not higher than the height of the top of the suction piston. Provided is a component arrangement structure of an intake system of a fuel injection engine characterized by being provided.

According to this structure, since the injector and the intake pressure sensor are provided at a position below the height of the top of the suction piston having a relatively large shape, even if they are swung, they are covered within the swing range of the suction piston. It is possible to dispose the injector and the intake pressure sensor by effectively utilizing the dead space generated by the swing of the engine without interfering with other parts around the engine.

In a preferred configuration example, the intake pressure sensor is attached to the throttle body adjacent to the suction piston, and the injector is attached to the intake passage downstream of the throttle valve of the throttle body.

According to this structure, the intake pressure sensor is compactly mounted adjacent to the suction piston of the throttle body, and the injector is compactly mounted on the downstream side of the throttle valve, for example, near the intake manifold.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an external view of a small motorcycle to which the present invention is applied.

The vehicle body 1 has a handle 2 at its front part, and the handle 2 is connected to front wheels 5 via a steering shaft 4 which passes through a head pipe 3. The body frame 6 is coupled to the head pipe 3. The vehicle body frame 6 forms a frame structure of the entire vehicle body. The front part of the vehicle body is covered with a cowling 7. The vehicle body 1 includes a vehicle body cover 8 from the outside of the vehicle body frame 6.
Covered with. A seat 9 is provided in the center of the vehicle body, a fuel tank 10 is provided below the seat 9, and a helmet box (a storage case) 11 is provided behind the fuel tank 10. The fuel tank 10 supplies fuel to an injector (not shown) via a fuel hose (not shown). A breather hose 12 is provided on the top of the fuel tank 10.
Is connected to one end and the other end is connected to the canister 13. The canister 13 is connected to an intake system (for example, a throttle body) via a purge hose 14. A throttle wire 15 is attached to a throttle grip (or lever) of a right handle portion (not shown) and is connected to a throttle valve of an intake system. Similarly, a brake cable 16 is attached to a brake lever (not shown) on the steering wheel, and the rear wheel 1
7 is connected to the brake cam shaft 18.

The engine unit 19 is attached to the vehicle body frame 6 at the center of the vehicle body. The engine unit 19
It is composed of an engine (not shown) and a speed reducer 24 integrally connected to a crankcase (not shown) of the engine. The engine unit 19 is rotatably suspended around a pivot 22 with respect to a lower body frame member 21 forming a part of the body frame 6 via an engine bracket 20. The rear wheel 17 is connected to the rear part of the engine unit 19, and the lower end of the damper 23 is pivotally mounted. The upper end of the damper 23 is pivotally attached to a rear body frame (not shown) that constitutes a part of the body frame 6. As a result, the engine unit 19 becomes swingable around the pivot 22 together with the rear wheel 17, and a swing unit type engine is formed.

An air cleaner 25 is provided above the speed reducer 24. The outside air intake opening 25a is provided at the front of the air cleaner 25.
Is provided, and a dustproof cover 26 made of rubber or resin is provided inside the vehicle body cover 8 so as to cover the opening. Two
7 is a stand and 28 is a kick lever.

2 and 3 are a side view and a plan view, respectively, showing a main part of a motorcycle equipped with the fuel injection engine according to the present invention. FIG. 4 is an enlarged view of the intake system part.

An engine 29 is provided below the fuel tank 10. The engine 29 is a four-cycle single cylinder engine equipped with a fuel injection injector. A crankcase (not shown) of the engine 29 is integrally coupled with a speed reducer 24 including, for example, a V-belt type continuously variable speed reducing mechanism, and constitutes a swing unit engine type engine unit 19 as a whole. The duct 30 is connected to the front part of the speed reducer 24, and the outside air is sucked from the open end 30a thereof to be supplied into the speed reducer 5 to cool the inside. A rear output shaft (not shown) of the speed reducer 24 is connected to an axle of the rear wheel 17.

An engine bracket 20 is integrally connected to the front portion of the swing unit engine type engine unit 19. A link plate 32 is pivotally attached to the engine bracket 20 via a shaft 31. The link plate 32 is connected to the lower body frame member 2 via the pivot 22.
1 is rotatably mounted.

A damper (shock absorber) 23 is provided at the rear of the engine unit 19. Damper 23
The upper end 33 is pivotally attached to the rear body frame member 34, and the lower end 35 is pivotally attached to a bracket 36 at the rear end of the engine unit 19. As a result, the engine unit 19 is swingably attached to the body frame about the pivot 22 on the front side thereof. As shown in FIG. 4, the cylinder 37 of the engine 29 is tilted forward almost horizontally. The crankshaft 38 has an arrow D along with the shaft 31 of the engine bracket 20 (FIG. 2) centering on the pivot 22.
Rocks like.

An intake manifold 39 communicating with an intake port (not shown) of the cylinder head is provided on the intake side of the engine 29.
Also, an intake pipe 40 (FIGS. 3 and 4) connected thereto is provided, and an exhaust pipe 41 (FIG. 3) is connected to the exhaust side. The intake pipe 40 is a bent elbow-shaped intake pipe, and as shown in FIG.
Are butted and fixed by two bolts 44. 45
Is a maintenance cover for the valve cam. The engine 29 is provided with a water temperature sensor 46 (FIGS. 3 and 4). The detection output signal of the water temperature sensor 46 is the water temperature signal cable 89 (FIG. 3).
And to the engine control unit 47 (FIG. 3) via the wire harness 72. Detection signal cables (not shown) for an intake air temperature sensor and an intake pressure sensor, which will be described later, are further connected to the engine control unit 47 via a wire harness 72, and a throttle valve (not shown) is controlled to open and close based on these detection data. To do.

A throttle body 48 is connected to the intake manifold 39 via the curved elbow-shaped intake pipe 40 described above. The throttle body 48 is connected to the air cleaner 25 via a joint 49. The injector 50 is attached to the intake pipe 40.

A throttle valve (not shown) is mounted in the throttle body 48, and a diaphragm type suction piston 51 is mounted upstream of the throttle valve. As will be described later, the suction piston 51 has a diaphragm chamber 52 provided above the throttle body 48, and an atmosphere intake port (atmosphere opening end) 54 of an atmosphere passage 53 for introducing atmosphere into the diaphragm chamber 52 has a throttle. It is provided below the body 48. A throttle wire 15 connected to a throttle lever (not shown) or a throttle grip (not shown) is connected to a valve shaft of the throttle valve via a link 55.

The air intake opening 25a at the front of the air cleaner 25 has a dustproof cover 26 made of rubber or resin (see FIG. 1).
(Dotted line) is covered. A vehicle body cover is further attached to the outside of the dustproof cover 26. The air intake 54 of the suction piston 51 opens inside the dustproof cover 26.

A heater wax type auto choke 56 and an intake pressure sensor 57 are provided on the throttle body 48 adjacent to the suction piston 51 (FIG. 3). The auto choke 56 opens and closes a bypass pipe (not shown) that connects the upstream side and the downstream side of the throttle valve. The intake pressure sensor 57 communicates with the intake manifold 39 or the intake pipe 40 via a negative pressure hose 58 (FIG. 4). An intake air temperature sensor 59 (FIG. 3) is provided in the air cleaner 25.

The intake pressure sensor 57 may be provided near the intake manifold. Further, a throttle position sensor (not shown) is provided on the valve shaft of the throttle valve on the side opposite to the link 55.
May be provided. In this case, the auto choke 56 is provided upstream of the throttle valve so as not to interfere with the throttle position sensor.

The front lower portion of the fuel tank 10 is fixed to the left and right vehicle body frame members 61 via brackets 60. A fuel hose 62 is pulled out from the rear of the fuel tank 10 and supplies fuel to the injector 50. The fuel hose 62 is fixed to the rear body frame member 34 via a stay 63 (FIGS. 2 and 4). 64 (FIG. 2) is an overflow pipe. Reference numeral 65 (FIG. 3) shows a battery, and 66 (FIG. 3) shows a recovery tank for cooling water. As shown in FIG. 3, a secondary air introduction system 86 for purifying exhaust gas is provided on the right side of the center of the vehicle body. This secondary air introduction system 8
6 communicates with the intake manifold via a negative pressure hose 87,
External air is supplied to a catalyst (not shown) via an air hose 88 according to negative intake pressure to reburn the exhaust gas.

A blow-by gas hose 90 is connected to the air cleaner 25, as shown in FIG. The blow-by gas hose 90 communicates with a cam chain chamber (not shown) that communicates with a crankcase (not shown) of the engine 29, and prevents oil seal dropout and loss horsepower due to pressure rise in the crankcase of the engine or the like. The blow-by gas hose 90 is connected to the clean side of the air cleaner after passing through the element, and the blow-by gas is introduced into the combustion chamber again.

FIG. 5 is a view showing the mounting state of the intake pressure sensor, which is a view of the throttle body portion as viewed from the right side of the vehicle body. Adjacent to the rear side surface of the diaphragm chamber 52 of the suction piston 51 mounted on the throttle body 48,
The intake pressure sensor 57 is attached to the bolt 10 via the bracket 73.
It is fixed to the throttle body 48 by 6. The intake pressure sensor 57 is connected to the intake manifold 39 via a negative pressure hose 58.
(Or the intake pipe 40).

FIG. 6 is a piping configuration diagram of the intake pressure sensor 57. A throttle body 48 is connected to the upstream side (air cleaner side) of the intake manifold 39 or the intake pipe 40. A throttle valve 74 is provided in the throttle body 48. The intake manifold 39 is provided with a negative pressure outlet 75, and a joint (negative pressure outlet pipe) 7 with a narrowed tip
6 is press-fitted and mounted. A negative pressure hose 58 is attached to the joint 76, and is fixed by tightening with a band 77.

The negative pressure hose 58 is connected so as to open at a position toward the detection center C of the intake pressure sensor 57 (for example, the center of the detection diaphragm). As a result, the intake negative pressure can be detected with high accuracy.

FIG. 7 is a configuration diagram of the intake passage. The intake pipe 40 is connected to an intake manifold 39 formed on a cylinder head of the engine by a bolt 44 via a flange 43 and a heat insulating material 42 at a mating surface P on the engine side.

The intake pipe 40 is made of, for example, an aluminum alloy,
A rubber joint 78 is baked and fixed to the upstream end. The throttle body 48 is press-fitted into the rubber joint 78, and the outer peripheral recess 78 a of the rubber joint 78 is
Fit a band (not shown) on and fix it. By connecting the throttle body 48 via such a rubber joint 78, vibrations from the engine are blocked to suppress noise leakage from the air cleaner to the outside, and the suction piston 51 and the throttle mounted on the throttle body 48 are also suppressed. It is possible to reduce the thermal influence on the valve 74 and the like and achieve highly accurate and reliable operation.

The suction piston 51 is a diaphragm chamber 5 integrally formed on the upper side of the throttle body 48.
2 and a piston 79 that moves back and forth in the intake passage 48a of the throttle body 48. The diaphragm chamber 52 has a first chamber (upper chamber) 81 and a second chamber (lower chamber) 82 partitioned by the diaphragm 80. First chamber 81
Penetrates the diaphragm 80 and communicates with the inside of the piston 79. A negative pressure port 83 is formed at the tip of the piston 79 to introduce intake negative pressure into the first chamber 81. A spring 84 is provided between the ceiling surface of the diaphragm chamber 52 and the bottom of the piston 79. By this spring 84, the piston 7
9 is urged in a direction of advancing into the intake passage 48a of the throttle body 48 (direction of closing the intake passage 48a). The intake negative pressure introduced into the piston 79 acts in the direction of pulling up the piston 79 (the direction of opening the intake passage 48a) against the spring 84.

An atmosphere passage 53 passing through the outer surface of the throttle body 48 communicates with the second chamber 82 below the diaphragm 80. Atmosphere intake 54 at the end of the atmosphere passage 53
Opens below the throttle body 48. 2nd chamber 8
Atmospheric pressure introduced from the atmospheric air intake 54 acts on 2. Therefore, the diaphragm 80 has the first
A force corresponding to the pressure difference between the chamber 81 and the second chamber 82 acts to move the piston 79 back and forth in the opening / closing direction.

Adjacent to the suction piston 51, the intake pressure sensor 57 is attached to the throttle body 48 via the bracket 73 (see FIG. 5) as described above. The intake pressure sensor 57 communicates with the intake manifold 39 via the negative pressure hose 58 as described above (see FIG. 6). Fuel tank (not shown) to the intake pipe 40 via a fuel hose 62
Is attached to the injector 50. The injector 50 is provided facing the intake passage on the downstream side of the throttle valve 74 of the throttle body 48. Both the intake pressure sensor 57 and the injector 50 are provided at a position lower than the top of the suction piston 51.

As described above, the intake pressure sensor 57 and the injector 50 are arranged in the space below the suction piston 51, which is the largest component of the intake system components attached to the throttle body 48. As a result, in the swing unit type engine, when the intake system swings, the intake pressure sensor 57 and the injector 50 do not interfere with the surrounding body frame and other parts, and these cannot be arranged by the surrounding parts. Can be efficiently accommodated within the swing range. The positions of the intake pressure sensor 57 and the injector 50 are not limited to the positions shown in the figure as long as they are below the suction piston 51, and the throttle body 48, the intake pipe 40, and the like depending on surrounding parts, the body frame structure, and the like. And the intake manifold 39 can be mounted at any suitable location.

FIG. 8 is a side view of the main part of the intake system of the engine. As described above, the engine unit 19 swings around the pivot 22 and the shaft 31 as two pivot points. The cylinder axis C of the engine 29 tilts forward, and an intake pipe 40 and a throttle body 48 are connected to an intake manifold 39 communicating with the cylinder head. A suction piston 51 is attached so as to project above the throttle body 48. The link 55 is fixed to the throttle valve shaft 93 of the throttle body 48. The end of the throttle wire 15 is locked to the bracket 96 and the wire core wire is fixed to the link 55. This allows the link 5 to be operated by the throttle operation.
5 is rotated to open / close a throttle valve (not shown) fixed to the valve shaft 93. 97 is an idol adjust task ryu.

An intake pressure sensor 58 is fixed to the throttle body 48 by a bolt 106 via a bracket 73 adjacent to the suction piston 51. Intake pressure sensor 5
7 communicates with the intake manifold 39 via a negative pressure hose 58. An injector 50 communicating with the fuel tank 10 (see FIG. 2) via a fuel hose 62 is attached to the intake pipe 40.

As described above, both the intake pressure sensor 57 and the injector 50 are provided at a position lower than the top of the suction piston 51. In this way, the intake pressure sensor 57 and the injector 50 are provided in the space below the suction piston 51, which is the largest of the intake system components attached to the throttle body 48.
In the swing unit type engine, the intake pressure sensor 57 is provided when the intake system swings.
The injector 50 does not interfere with the surrounding body frame and other parts (for example, the battery 65 shown in FIG. 3 and a transverse frame (not shown) connecting the left and right body frames 34 behind it, a fuel tank, etc.). ,
These can be efficiently accommodated within the swing range of the intake system where the peripheral parts cannot be arranged. The fuel tank 10
There may be a case where a helmet box (a storage case) is arranged. Also in this case, as in the case of the fuel tank,
The injector 50, the intake pressure sensor 57, and the like can be arranged in the swinging intake system space below the helmet box without interfering with the bottom surface of the helmet box or other components.

[0043]

As described above, according to the present invention, the injector and the intake pressure sensor are provided at a position below the height of the top portion of the suction piston having a relatively large shape. The injector and the intake pressure sensor can be arranged by being covered by the swing range and not interfering with other parts around the engine and effectively utilizing the dead space generated by the swing of the engine.

[Brief description of drawings]

FIG. 1 is an external view of a small motorcycle according to the present invention.

FIG. 2 is a side view of a main part of the motorcycle shown in FIG.

FIG. 3 is a plan view of a main part of the motorcycle shown in FIG.

FIG. 4 is a configuration diagram of an engine portion of the motorcycle of FIG.

5 is a mounting structure diagram of the intake pressure sensor of the motorcycle of FIG.

FIG. 6 is a layout configuration diagram of the intake pressure sensor of FIG.

FIG. 7 is a configuration diagram of an intake passage according to the present invention.

FIG. 8 is a side view of the main part of the intake system of FIG.

[Explanation of symbols]

1: vehicle body, 2: steering wheel, 3: head pipe, 4: steering shaft, 5: front wheel, 6: vehicle body frame, 7: cowling, 8: vehicle body cover, 9: seat, 10: fuel tank, 11: helmet box, 12: breather hose, 13: canister, 14: purge hose, 15: throttle wire, 16: brake cable, 17: rear wheel, 18: brake camshaft, 19: engine unit, 20: engine bracket, 21: lower body frame Member, 22: pivot, 23: damper, 24:
Reduction gear, 25: Air cleaner, 25a: Air intake opening, 26: Dust cover, 27: Stand, 28: Kick lever, 29: Engine, 30: Duct, 30a: Open end, 31: Shaft, 32: Link Plate, 33: top,
34: rear body frame member, 35: lower end, 36: bracket, 37: cylinder, 38: crankshaft, 39: intake manifold, 40: intake pipe, 41: exhaust pipe, 42: heat insulating material, 43: flange, 44: Bolts, 45: maintenance cover, 46: water temperature sensor, 47: engine control unit, 48: throttle body, 49: joint, 49
a: joint end, 50: injector, 51: suction piston, 52: diaphragm chamber, 53: atmosphere passage, 54: atmosphere intake, 55: link, 56: auto choke, 57: intake pressure sensor, 58: negative pressure Hoses, 5
9: intake air temperature sensor, 60: bracket, 61: vehicle body frame member, 62: fuel hose, 63: stay, 64: overflow pipe, 65: battery, 66: recovery tank, 72: wire harness, 73: bracket,
74: throttle valve, 75: negative pressure outlet, 76: joint, 77: band, 78: rubber joint, 78
a: concave portion, 79: piston, 80: diaphragm, 8
1: first chamber, 82: second chamber, 83: negative pressure port, 84:
Spring, 86: Secondary air introduction system, 87: Negative pressure hose, 88: Air hose, 89: Water temperature signal cable,
90: blow-by gas hose, 91: blow-by gas pipe, 106: bolt.

Claims (2)

[Claims] 1. An engine is swingably attached to a body frame together with a rear wheel, a throttle body is provided on an intake passage above a swing center of the engine, and a suction piston is attached so as to project above the throttle body. In the intake system of the fuel injection engine, the injector and the intake pressure sensor are provided in the throttle body or the intake passage within a range of the height of the top of the suction piston or less. Arrangement structure. 2. The intake pressure sensor is attached to a throttle body adjacent to a suction piston, and the injector is attached to an intake passage downstream of the throttle valve of the throttle body. Structure of the intake system parts for fuel injection engine.