Throttle body

A throttle body for controlling a plurality of throttle valves in a multi-cylinder engine. The throttle valves of at least two of the cylinders are structurally connected to each other.

TECHNICAL FIELD

The present invention relates, for example, to an electronic controlled throttle body used in a multi-cylinder engine.

BACKGROUND

In recent years, it has been common to use an electronic throttle control device that detects the actuated amount of a throttle grip or an accelerator pedal and controls, based on the actuated amount of the throttle grip or the accelerator pedal, the opening of a throttle valve through a motor.

When the throttle control device of this type is to be disposed in an engine provided with an injector supplying fuel through injection into an intake passageway, it is desirable that, for example, a motor and a throttle opening sensor be disposed as compactly as possible, while avoiding interference with a fuel injection valve.

An arrangement is known in which the motor is disposed on the same side as the injector. See Japanese Patent Laid-open No. 2002-256895. If the motor is disposed on the same side as the injector, however, a wide space must be provided on an upper portion of the throttle body. This presents the problem of uneven distribution of a space around the throttle body.

In some known configurations, the motor and the throttle opening sensor may be disposed in an axial direction of the throttle valve. This, however, results in the length of the throttle body in the direction of cylinder arrangement being elongated by the length of these parts. This, in turn, leads to an enlarged engine.

SUMMARY

The present invention is related to a throttle body. The throttle body can be used in a motor for controlling a throttle valve in a multi-cylinder internal combustion engine.

According to one aspect of the invention, a throttle body includes some of a plurality of throttle valves that are structurally connected together. This arrangement preferably allows the throttle valves connected together to be disposed in close proximity to each other, thus contributing to a shorter length in the cylinder arrangement direction. The arrangement also preferably allows the connected throttle valves to be integrally driven.

According to another aspect, a throttle body for controlling a throttle valve in an internal combustion engine includes a throttle opening sensor that detects the opening of the throttle valve and an injector that are disposed oppositely on either side of a throttle body main body. This arrangement disposes the throttle opening sensor and the injector on either side of the throttle body main body. The arrangement thus preferably allows a space around the throttle body main body to be compactly arranged, enabling an effective use of the surrounding space.

According to yet another aspect, the motor and an injector are disposed oppositely on either side of a throttle body main body. This arrangement disposes the motor and the injector on either side of the throttle body main body. The arrangement thus preferably allows a space around the throttle body main body to be compactly arranged, enabling an effective use of the surrounding space.

According to another aspect, some of a plurality of throttle valves are structurally connected together. This arrangement preferably allows engine valves to pause in at least part of the cylinders in the multi-cylinder internal combustion engine. This arrangement preferably allows the throttle valve to be closed by the motor in the cylinder, in which the engine valves pause.

DETAILED DESCRIPTION

A first preferred embodiment of the present invention will be described with reference to the accompanying drawings. Referring toFIGS. 1 and 2, a water-cooled four-cycle in-line four-cylinder engine1is used in a motorcycle.

The engine1is mounted on a vehicle body frame with a crankshaft (not shown oriented toward a vehicle width direction).

The engine1comprises a cylinder block2, on a top surface of which a cylinder head3is secured. Further, a head cover4is attached to a top surface of the cylinder head3. A cam chain case5is formed on a side portion of the engine1. The engine1is provided with cylinders in order of cylinder #1, cylinder #2, cylinder #3, and cylinder #4from the side of the cam chain case5. Each cylinder is provided with two intake valves and two exhaust valves, to be described further below.

The aforementioned four cylinders are disposed in the vehicle width direction. An intake valve opening8and an exhaust valve opening9are formed in a recessed portion7forming a combustion chamber6of the cylinder head3in each of these cylinders. The intake valve opening8and the exhaust valve opening9are opened and closed by an intake valve10and an exhaust valve11, respectively.

An exhaust port12, communicating with the exhaust valve opening9, is formed to face a front wall of the cylinder head3and connected to an exhaust pipe not shown. An intake port13, communicating with the intake valve opening8, is formed to face a rear wall of the cylinder head3. A throttle body14is connected to each intake port13.

The throttle body is connected substantially horizontally. An intake duct16is connected to an air intake port15on an upstream side of the throttle body14. An air cleaner18provided with an air cleaner element17is provided inside the intake duct16. Intake air that flows through the air cleaner18is introduced into each cylinder through the throttle body14.

A butterfly type throttle valve20is provided in an intake passageway19of the throttle body14. The throttle valve20can be actuated between a fully open position and a fully closed position. The throttle valve20is preferably of an electronic throttle control type. Specifically, the throttle valve20is opened or closed, being operatively connected to a motor21(21A,21B), in accordance with a grip opening manipulated by a rider to accelerate or decelerate. A throttle opening sensor22for detecting a throttle opening is operatively connected to the throttle valve20. The throttle opening sensor22is capable of accurately detecting a rotating angle of the throttle valve20as the throttle valve20is rotated by the motor21.

More specifically, the throttle body14comprises four throttle valves20,20,20,20provided in a throttle body main body140, as shown inFIG. 4. The throttle body main body140comprises three sections connected to each other: a first-second throttle body main body140A corresponding to cylinder #1and cylinder #2; a third throttle body main body140B corresponding to cylinder #3; and a fourth throttle body main body140C corresponding to cylinder #4.

A mounting bracket24for the third throttle body main body140B is tightened and secured using a bolt25to a mounting bracket23provided on an upper portion of the first-second throttle body main body140A. A mounting bracket27for the fourth throttle body main body140C is tightened and secured using a bolt28to a mounting bracket26of the third throttle body main body140B.

The throttle valves20of the first-second throttle body main body140A are connected to each other through a common first-second shaft29. Both end portions of the first-second shaft29are rotatably supported through bearings30by the first-second throttle body main body140A. That is, two of the total four throttle valves20are structurally connected to each other. The throttle opening sensor22is mounted on the first-second throttle body main body140A with screws31coaxially on an end portion of the first-second shaft29on the side of the cam chain case5. A pulley32is mounted on an end portion of the first-second shaft29opposite to the cam chain case5. Injectors33,33are inserted and secured slantwise toward each intake valve10on an upper portion, or an upper wall, of the first-second throttle body main body140A. Each injector33injects fuel into each intake passageway19.

The injectors33are connected to a fuel supply pipe34(seeFIGS. 1 and 2). The first-second motor21A is mounted on a side of the first-second throttle body main body140A opposite to the injector33. The first-second motor21A is mounted by means of a clamping bracket36so that a driving shaft35thereof runs parallel with the first-second shaft29. A pulley42is mounted on an end portion of the driving shaft35of the first-second motor21A opposite to the cam chain case5.

Both end portions of a shaft37of the throttle valve20of the third throttle body main body140B are rotatably supported through the bearings30on the third throttle body main body140B. A pulley38having two pulley grooves38M,38S is mounted on an end portion of the shaft37opposite to the cam chain case5. There is an injector33having the same configuration as that described earlier provided on an upper portion of the third throttle body main body140B. The injector33is inserted and secured slantwise toward the intake valve10.

A mounting seat39is formed in an extended manner on a lower portion of the third throttle body main body140B. A sensor shaft40of a throttle opening sensor22is mounted to this mounting seat39. The sensor shaft40is inserted by way of a bearing30and secured in position with screws31so as to run parallel with the shaft37. A pulley41is mounted on an end portion of the sensor shaft40of the throttle opening sensor22opposite to the cam chain case5. That is, the throttle opening sensor22is mounted on a side opposite to the injector33.

The motor21B is mounted by way of a bracket, not shown on a front side of the throttle opening sensor22and on an opposite side of the injector33. The motor21B is mounted so that a driving shaft35thereof runs parallel with the shaft37. A pulley42is mounted on an end portion of the driving shaft35of the motor21B opposite to the cam chain case5. The motor21B is therefore preferably mounted on a side opposite to the injector33. As shown also inFIG. 3, the pulley groove38M in the pulley38of the shaft37and a pulley groove in the pulley42of the motor21B are connected by way of an endless wire43. The pulley groove38S in the pulley38of the shaft37and a pulley groove in the pulley41of the throttle opening sensor22are connected by way of an endless wire44.

The fourth throttle body main body140C has substantially the same configuration as the third throttle body main body140B. Both end portions of a shaft37of the throttle valve20are rotatably supported through bearings30on the fourth throttle body main body140C. A pulley38having two pulley grooves38M,38S is mounted on an end portion of the shaft37opposite to the cam chain case5. An injector33, having the same arrangement as that described earlier, is also mounted on an upper portion of the fourth throttle body main body140C. The injector33is inserted and secured slantwise toward the intake valve10.

A mounting seat39is formed in an extended manner on a lower portion of the fourth throttle body main body140C. A sensor shaft40of a throttle opening sensor22is mounted to this mounting seat39. The sensor shaft40is inserted by way of a bearing30and secured in position with screws31so as to run parallel with the shaft37. A pulley41is mounted on an end portion of the sensor shaft40of the throttle opening sensor22opposite to the cam chain case5. That is, the throttle opening sensor22is mounted on a side opposite to the injector33.

The motor21B is mounted by way of a bracket, not shown on a front side of the throttle opening sensor22and on an opposite side of the injector33. The motor21B is mounted so that a driving shaft35thereof runs parallel with the shaft37. A pulley42is mounted on an end portion of the driving shaft35of the motor21B opposite to the cam chain case5. That means that the motor21B is mounted on a side opposite to the injector33. The pulley groove38M in the pulley38of the shaft37and a pulley groove in the pulley42of the motor21B are connected by way of an endless wire43. The pulley groove38S in the pulley38of the shaft37and a pulley groove in the pulley41of the throttle opening sensor22are connected by way of an endless wire44.

As shown inFIGS. 5 and 6, a valve pause mechanism is provided for the intake valve10and the exhaust valve11in each cylinder of the engine1.

In each ofFIGS. 5 and 6, only one intake valve10of two intake valves10is shown. The other intake valve10and the two exhaust valves11are omitted in the drawings for clarity purposes.

The valve pause mechanism50includes the following components: a valve lifter52of a cap shape vertically slideably fitted by insertion into the cylinder head3and slidingly contacting a valve moving cam51; a pin holder53vertically slideably fitted into the valve lifter52; a slide pin55slideably fitted in the pin holder53to form a hydraulic chamber54(shown only inFIG. 6) with an inner peripheral surface of the valve lifter52; and a return spring56provided in a space between the slide pin55and the pin holder53and exhibiting a spring force urging the slide pin55in a direction of reducing a volume of the hydraulic chamber54. A hydraulic supply passageway63for supplying the hydraulic chamber54with hydraulic oil is provided in the cylinder head3.

A retainer58is provided for a valve stem57of the intake valve10. A coil spring59provided between the retainer58and the cylinder head3biases the intake valve10in a direction of closing the intake valve opening8. A coil spring60disposed on an outside of the coil spring59biases the pin holder53upward.

A hole61passing through an end portion of the valve stem57of the intake valve10is formed in a bottom wall of the pin holder53. A receiving hole62receiving the end portion of the valve stem57is formed in the slide pin55.

Referring toFIG. 5, when hydraulic oil is not being supplied through the hydraulic supply passageway63to the hydraulic chamber54, the force of the return spring56moves the slide pin55to the right inFIG. 5. This brings the receiving hole62into alignment with the hole61in the pin holder53. As a result, the end portion of the valve stem57of the intake valve10is inserted through the receiving hole62. In this configuration, the motion of the valve moving cam51is not transmitted to the intake valve10, allowing the intake valve10to pause.

Referring, on the other hand, toFIG. 6, when the hydraulic oil is supplied through the hydraulic supply passageway63to the hydraulic chamber54, the return spring56contracts, causing the slide pin55to move to the left inFIG. 6. The end portion of the valve stem57is not therefore inserted into the receiving hole62. A bottom surface of the slide pin55then abuts on a leading end of the valve stem57. The motion of the valve moving cam51is then transmitted to the intake valve10. The intake valve10therefore operates.

The hydraulic oil, in an oil pan64, is supplied to a main hydraulic passageway66by a pump65. A branch passageway67from the main hydraulic passageway66is connected to the hydraulic supply passageway63. A spool valve68is provided for the branch passageway67. The spool valve68functions as follows. When the spool valve68is operated to a position in which the hydraulic oil is supplied through the branch passageway67to the hydraulic supply passageway63(FIG. 6), the intake valve10is placed in an active state. When the spool valve68is operated to a position in which the hydraulic oil is supplied through the branch passageway67by way of a drain passageway69back to the oil pan64(FIG. 5), the intake valve10is placed in a pause state.

The spool valve68is operated based on an input signal to an ECU70, such as a signal indicating a grip opening, an engine speed NE, or the like. The ECU70produces an output of a rotation command signal to each of the motors21A,21B, driving the throttle valve20based on an opening signal provided by the throttle opening sensor22. A fuel injection amount at the injector33is adjusted based on a control signal from the ECU70.

When the throttle valve20is rotated by each of the motors21A,21B through detection of the grip opening, a predetermined amount of fuel in accordance with the detected grip opening is injected from the injector33. If, at this time, predetermined conditions are met to let the intake valve10pause, supply of fuel from the injector33can be stopped by the ECU70and the throttle valve20can be closed by driving the motors21A,21B. When the valve pause is canceled and the intake valve10is operated again, therefore, the throttle valve in the closed position can be operated to gradually open using the motors21A,21B.

FIG. 7, on which the abscissa represents the grip opening and the ordinate represents the throttle valve opening, illustrates the following. Specifically, when the grip starts opening, the opening of the throttle valves20in cylinder #1and cylinder #2increases. When the throttle valves20in cylinder #1and cylinder #2are fully open, the throttle valve20in cylinder #3opens according to the grip opening. When throttle valve20in cylinder #3fully opens, then the throttle valve20in cylinder #4opens according to the grip opening.

In a range having a small grip opening, therefore, the throttle valves20are integrated together in the two cylinders of cylinder #1and cylinder #2, thus allowing throttle control to be performed even more precisely.

In accordance with the embodiment of the present invention described in the foregoing, the throttle valves20,20corresponding to cylinder #1and cylinder #2are structurally connected together by means of the common first-second shaft29. This allows the connected throttle valves20,20to be disposed in close proximity to each other. This arrangement helps shorten the length of the engine1in the direction of cylinder layout. The arrangement also allows the connected throttle valves20,20to be integrally driven.

A lightweight engine1can therefore be made. Reliability in the electronic throttle control device can also be even further enhanced, since the connected throttle valves20,20can be controlled to open or close simultaneously according to the intention of the rider to accelerate or the like. As touched upon earlier, the throttle opening sensor22is mounted on the end portion of the first-second shaft29for the first-second throttle body main body140A. The throttle valves20,20are structurally connected together using the first-second shaft29, which results in the length in the vehicle width direction being shorter by the amount corresponding to the structural connection. This provides for extra allowance for the length. The throttle opening sensor22does not, therefore, contribute to an increased dimension in the width of the engine1.

The throttle opening sensor22and the injector33are disposed oppositely on either side of the third or fourth throttle body main body140B,140C. This allows the throttle opening sensor22and the injector33to be disposed separately over the third or fourth throttle body main body140B,140C located therebetween. The arrangement thus allows a space around the third and the fourth throttle body main body140B,140C to be compactly arranged, enabling an effective use of the surrounding space.

As a result, even when the embodiment of the present invention is applied to a multi-cylinder engine including the four-cylinder engine as embodied in the present invention, there is no need of expanding the gap between cylinders. Thus, downsizing of the engine1is achieved.

The first-second motor21A and the injector33are disposed oppositely on either side of the first-second throttle body main body140A. This allows the first-second motor21A and the injector33to be disposed separately over the first-second throttle body main body140A located therebetween. The arrangement thus allows a space around the first-second throttle body main body140A to be compactly arranged, enabling an effective use of the surrounding space.

As a result, even when the embodiment of the present invention is applied to a multi-cylinder engine including the four-cylinder engine as embodied in the present invention, there is no need of expanding the gap between cylinders. Thus, downsizing of the engine1is achieved.

The engine is therefore preferably constructed so that the intake valve10and the exhaust valve11can be brought into a pause state in part of the cylinders of the engine1, or all of the four cylinders according to the embodiment of the present invention. When the intake valve10and the exhaust valve11are in the pause state, therefore, the throttle valve22can be operated to close using the motor21. This preferably prevents a valve actuation operation from being resumed from the valve pause state with the throttle valve22left open. This allows the valve pause state to smoothly shift to the valve actuation state. That is, the electronic throttle control device, using the motor21to open or close the throttle valve20, is combined with the valve pause mechanism50. This combination allows the throttle valve20to be closed during the valve pause state. A closed throttle valve20can therefore be gradually opened during transition to the valve actuation state. As a result, a shift from the valve pause operation to the valve actuation operation can be smoothly made.

The present invention has been described with reference to a specific exemplary embodiment thereof as applied to a motorcycle. It will be understood that the invention is not limited thereto and can also be applied to a four-wheel vehicle. In an application to a four-wheel vehicle, the accelerator pedal opening can be used instead of the grip opening. The present invention has also been described with reference to a specific exemplary embodiment thereof, wherein each of the four cylinders is provided with four valves. The invention nonetheless can be applied to an engine having two valves in each cylinder. The valve pause mechanism is only an example. A valve pause mechanism using a rocker arm to let the valve pause can still be used. Various forms of other embodiments are possible, including one embodiment in which one pair of the intake valve and the exhaust valve of a cylinder is caused to pause, with the other intake and exhaust valves being operated normally.