JP2003106226A - Intake temperature detecting structure for fuel injection engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intake temperature detecting structure for a fuel injection engine capable of minimizing the thermal influence from an engine and the influence of a flow speed, detecting the proper intake temperature necessary for controlling the engine drive, and providing a compact structure. SOLUTION: This intake temperature detecting structure for an fuel injection engine is provided with an air cleaner 25 mounted on an end part of an intake passage 137, a throttle body 48 mounted on the way of the intake passage, an injector 50 faced to an intake passage (intake pipe 40) at a downstream side of the throttle body 48, and an intake temperature sensor 59 for detecting the intake temperature. The air cleaner 25 has a case 67 having an opening 25a for taking the air, and a filter element 68 mounted in the case 67, and an end part of the intake passage (joint) 49 is faced into the case 67. The intake temperature sensor 59 is mounted in the case 67 of the air cleaner 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake temperature detecting structure for a unit swing type 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.

In the intake system of this engine, an air cleaner is provided at the end of the intake passage, and outside air is introduced through the air cleaner. A throttle body forming a part of the intake passage is connected in the middle of the intake passage. A throttle valve is provided in the throttle body to control the intake air amount. An injector is provided facing the intake passage on the downstream side of the throttle body to inject fuel. The intake air that has been injected with fuel to become an air-fuel mixture is sucked into the engine combustion chamber through the intake manifold and the intake valve at the downstream end of the intake passage.

Since injection control and ignition control are performed according to the operating state of such a fuel injection engine, cooling water temperature, intake air temperature, intake negative pressure, etc. are detected, and these detection signals are sent to the engine control unit (ECU). Sent. The ECU controls the drive of the engine according to a predetermined program or map based on these operating state detection signals.

Conventionally, in order to detect the intake air temperature, the temperature sensor detects the atmospheric temperature outside the intake system, and based on the atmospheric temperature, the intake air temperature is corrected with respect to the fuel injection amount, ignition timing, etc., and the engine is driven and controlled. Was.

[0007]

However, if the atmospheric temperature outside the intake system is detected and the intake air temperature is used for the calculation process, the injector portion in which fuel is actually injected in the intake passage located near the engine. Therefore, the difference between the intake air temperature and the intake air temperature becomes large, and there is a possibility that optimal control cannot be performed according to the operating state. In addition, there is a large space constraint on the temperature sensor arrangement, and especially for small motorcycles that require a compact configuration around the engine, providing a temperature sensor outside the intake system will result in a compact layout in terms of component arrangement. Disappear.

To cope with this, if a temperature sensor is provided in the intake pipe to detect the temperature inside the intake passage, heat from the engine will affect the temperature sensor through the metal intake pipe made of aluminum alloy or the like, causing deterioration. And the problem of low reliability of detection occur. Further, when the temperature of the intake air in the intake passage is detected, the temperature fluctuates due to the change in the flow velocity of the intake air, and stable and highly reliable temperature detection becomes impossible.

The present invention has been made in consideration of the above-mentioned conventional technique, and minimizes the thermal influence from the engine and the influence of the flow velocity, detects an appropriate intake temperature necessary for engine drive control, and is compact. The present invention aims to provide a structure for detecting an intake air temperature of a fuel injection engine that can obtain such a structure.

[0010]

In order to achieve the above object, in the present invention, an air cleaner provided at an end portion of an intake passage, a throttle body mounted in the middle of the intake passage, and a downstream side of the throttle body. An injector facing the intake passage and an intake air temperature sensor for detecting the intake air temperature are provided, and the air cleaner has a case having an air intake opening and a filter element provided in the case, and the intake air is provided in the case. In the intake air temperature detection structure of the fuel injection engine facing the end of the passage, the intake air temperature sensor is
Provided is an intake air temperature detecting structure for a fuel injection engine, which is provided in a case of the air cleaner.

According to this structure, the intake air temperature sensor is mounted on the case of the air cleaner, and the intake air temperature introduced into the engine is detected from the temperature inside the air cleaner at the end portion of the intake pipe, so that the temperature of the engine through the intake pipe is increased. In addition to minimizing the thermal effect, it is possible to detect the intake air temperature at the position closest to the temperature in the intake pipe, and obtain an appropriate intake air temperature required for engine drive control.

In a preferred configuration example, the case has a bulge portion near the end portion of the intake passage, the bulge portion being out of the flow path of the intake air, and the bulge portion being provided with the intake air temperature sensor. .

According to this structure, since the intake air temperature of the bulging portion at a position outside the intake air flow path in the air cleaner is detected, the intake air temperature is not affected by the flow velocity of the intake air, and the accurate intake air temperature is detected. The bulging portion has a function as a resonator, and suppresses torque fluctuations of the engine due to blow-in or reverse push-back of intake air due to the relationship between the exhaust and intake valve timings.

In a further preferred configuration example, the intake air temperature sensor is mounted adjacent to the end portion of the intake passage and at a position at the same height as this.

According to this structure, since the intake air temperature sensor is provided laterally adjacent to the end portion of the intake pipe which faces the inside of the air cleaner and projects into the case, the intake air temperature sensor and its mounting portion to the case are provided. It is arranged at a position covered by the intake pipe in the vertical direction, and a compact structure is obtained.

[0016]

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 the front wheels 5 via a steering shaft 4 through which a head pipe 3 is inserted. 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 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 above-mentioned bent elbow-shaped intake pipe 40. 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 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 horizontal sectional view of the air cleaner 25. The air cleaner 25 has a cylindrical filter element 68 mounted in a case 67. The air intake opening 25a opens in the case 67. A duct 69 is connected to the filter element 68. The outside air introduction port 70 at the end of the duct 69 opens to face the air intake opening 25a formed in the case 67. A joint 49 is connected to the front portion of the case 67, and the joint end 4
9 a faces the inside of the case 67 and opens. A blow-by gas hose 90 is provided at a position outside the duct 69 in the case 67.
A blow-by gas pipe 91 for connecting (FIG. 2) is provided. Reference numeral 100 is a drain pipe, and 100a is its stopper.

The outside air has an air intake opening 2 by negative pressure of intake air.
5a (arrow A), flows in the duct through the outside air intake 70 of the duct 69 (arrow B), passes through the inside of the cylindrical filter element 68 from the outer peripheral side (arrow C), and escapes into the case 67 ( (Arrow D) is introduced into the joint 49 from the joint end 49a (arrow E), and is sucked by the engine 29 through the throttle body 48 and the intake pipe 40 as shown in FIGS.

The case 67 has a flow path for the outside air (arrow A,
B, C, D, E) has a bulge portion 67a at a position apart from it. The intake air temperature sensor 59 is attached to the bulging portion 67a via the grommet 71. This intake air temperature sensor 59
It is connected to the engine control unit 47 (FIG. 3) via a lead wire (not shown) and a wire harness 72 (FIG. 3). In this way, by providing the intake air temperature sensor 59 in the bulging portion 67a (the portion that functions as a resonator that suppresses torque fluctuations of the engine and retains air) that is off the outside air flow path of the case 67, the flow rate of the outside air to be sucked The outside air temperature can be detected stably and accurately without being affected.

Further, by mounting the intake air temperature sensor 59 on the case 67 made of a resin material through the grommet 71 made of rubber or another elastic resin material, the intake air temperature sensor 5
The heat transfer from the engine to 9 is effectively blocked,
The intake air temperature sensor 59 is thermally protected and a highly reliable function is maintained.

6 and 7 are a top view and a side view, respectively, showing the structure of the entire intake passage according to the present invention.

As shown in the figure, the intake passage 137 includes an intake manifold 39 having an intake valve 99 attached to an end thereof,
The intake pipe 40 to which the injector 50 is attached, the throttle body 48 to which the throttle valve 74 is attached, and the joint 49 to which the air cleaner 25 is connected are connected. The joint end 49a is an air cleaner 2
5 and projects into the case 67. Case 67 is
An air intake opening 25a is provided, and the air intake opening 25a
The outside air introduction port 70 at the end of the duct 69 opens to face a. The duct 69 is connected to the filter element 68. As shown by the dotted arrow R in the figure, the air intake opening 25
A flow path is formed in the case 67 from a through the duct 69, the filter element 68, and the joint end 49a into the intake passage 137. As described above, the intake air temperature sensor 59 is attached to the bulging portion 67a of the case 67 at a position outside the flow path R.

As shown in FIG. 7, the intake air temperature sensor 59 is mounted adjacent to the end of the joint 49 protruding into the case 67 and at a position substantially the same height as the end of the joint 49. With such an arrangement, the intake air temperature sensor 59 does not protrude from the joint 49 in the vertical direction, and a compact structure can be obtained.

[0039]

As described above, according to the present invention, the intake air temperature sensor is mounted on the case of the air cleaner, and the intake air temperature introduced into the engine is detected from the temperature inside the air cleaner at the end of the intake pipe. The thermal influence of the engine via the intake pipe can be minimized, and the intake air temperature at the position closest to the temperature in the intake pipe can be detected, so that an appropriate intake temperature required for engine drive control can be obtained.

Further, by detecting the intake air temperature of the bulging portion (resonator portion) located outside the intake air flow path in the air cleaner, a stable and accurate intake air temperature can be detected without being influenced by the flow velocity of the intake air. .

Further, by providing an intake air temperature sensor on the side adjacent to the end portion of the intake pipe projecting into the air cleaner, the intake air temperature sensor and its mounting portion to the case are vertically connected to the intake pipe (joint). It is arranged in a covered position and a compact structure is obtained.

[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 horizontal sectional view of the air cleaner of the motorcycle of FIG.

FIG. 6 is a plan view of an intake passage according to the present invention.

FIG. 7 is a side view of the intake passage 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, 67: case, 67a: bulge part, 68 : Filter element, 69: duct, 70: outside air inlet, 7
1: Grommet, 72: Wire harness, 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, 99: Intake valve, 100: Drain pipe, 100a: stopper, 137: intake passage.

Claims (3)

[Claims] 1. An air cleaner provided at an end of an intake passage, a throttle body mounted midway in the intake passage, an injector facing the intake passage downstream of the throttle body, and an intake air temperature sensor for detecting an intake air temperature. The air cleaner has a case having an air intake opening and a filter element provided in the case, and an intake air temperature detection structure for a fuel injection engine in which the end of the intake passage faces the case. In the intake air temperature detection structure for a fuel injection engine, the intake air temperature sensor is provided in a case of the air cleaner. 2. The case has a bulge portion near the end of the intake passage, the bulge portion being out of the flow path of the intake air, and the bulge portion being provided with the intake air temperature sensor. The intake air temperature detection structure for the fuel injection engine described in 1. 3. The fuel injection engine according to claim 1 or 2, wherein the intake air temperature sensor is mounted adjacent to the end portion of the intake passage and at a position substantially equal in height to the end portion. Intake temperature detection structure.