JPH0452447Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel control device for an internal combustion engine in which the fuel control member is not mechanically connected to the accelerator pedal.

[Prior Art] In an automatic transmission device that automatically operates a conventional manual synchronized mesh transmission in conjunction with a clutch mechanism, the mechanical connection between the carburetor or fuel injection pump of the internal combustion engine and the accelerator pedal is separated. The throttle valve or fuel lever as a fuel control member is driven by a step motor, and the step motor receives signals from an accelerator sensor (potentiometer, etc.) that detects the amount of depression of the accelerator pedal, and detects driving conditions such as starting and shifting. It is controlled by an electronic control device that receives as input a signal from a sensor that detects a change.

As a fuel control device for an internal combustion engine suitable for the above-mentioned automatic transmission, the device disclosed in Japanese Patent Application Laid-open No. 14834/1983 includes a step motor controlled by an electronic control device and a throttle valve as a fuel control member. Since these are directly connected, it takes time to mechanically set the characteristics of the potentiometer as an accelerator sensor and the opening degree of the throttle valve, as well as to initialize the program. In other words, if there are variations in the characteristics of the potentiometer, it will take a lot of effort to set the potentiometer so that the detection voltage of the potentiometer is 0 at the position where the accelerator pedal is released during factory assembly, and it will also be difficult to Meter characteristics (relationship between operating amount and resistance value)
When this changes, the amount of operation of the step motor controlled by the electronic control device (computer) changes, resulting in a decrease in control accuracy.

Furthermore, if the step motor is directly connected to the throttle valve, there is a risk that the automatic choke mechanism and fuel increase mechanism necessary for cold start of the engine will not work, or even if they do work, the control operation of the step motor will be unreasonable.

[Problems to be solved by the invention] In view of the above-mentioned problems, the purpose of the invention is to eliminate the need for special settings for the correspondence between the accelerator pedal and the accelerator sensor, and to prevent the characteristics of the accelerator sensor from changing during long-term use. An object of the present invention is to provide a fuel control device for an internal combustion engine that does not cause a change in control accuracy even when the engine is in use.

[Means for Solving the Problem] In order to achieve the above object, the configuration of the present invention fixes and supports the fuel lever on a shaft that connects the fuel control member, and supports the drive lever so as to be freely rotatable.
The spring that biases the rotation of the fuel lever toward the idle position biases the protrusion of the fuel lever against the protrusion of the drive lever, causing a disk cam connected to the fuel lever to close the switch and close the switch at the idle position of the fuel control member. An actuating part is provided to open the switch at the maximum fuel amount position, and in the closing operation range of the switch, a signal corresponding to a change in resistance of a potentiometer that detects the amount of depression of the accelerator pedal is sent to a step motor that drives the drive lever. It is equipped with an electronic control device.

[Operation] When the drive lever is rotated by the step motor in the fuel increasing direction around the valve shaft, the protruding piece of the drive lever hits the fuel lever, and the fuel lever releases the fuel together with the valve shaft that supports the fuel control member. Rotated in the direction of increase.

Conversely, when the drive lever is rotated by the step motor in the direction of decreasing fuel, the fuel lever follows the drive lever and is returned by the spring that biases the valve shaft to rotate toward the idle position. Therefore, even if the fuel lever is operated in the fuel increasing direction by an automatic choke mechanism or the like, the operation of the drive lever driven by the step motor is not hindered.

In addition, if the potentiometer as an accelerator sensor wears out after long-term use and the rate of change in resistance value with respect to rotation angle becomes smaller, the amount of depression of the accelerator pedal to fully open the throttle valve will increase. However, the opening degree of the throttle valve changes in proportion to the amount of depression, and when the throttle valve reaches the fully open position, the step motor does not rotate any further due to the action of the cam mechanism and switch, so no readjustment is necessary.

[Embodiment of the invention] The invention will be described based on an embodiment in which the fuel control member is a throttle valve of a carburetor. As shown in FIG. 1 for a four-cylinder engine, an intake manifold 41 is provided with a flat mounting surface 42 having openings 3a, 4a, on which a carburetor (not shown) is placed, and bolt holes 43 It is fixed by screwing a bolt into it. A step motor 6 is attached to a bracket 45 fixed to the intake manifold 41 with bolts 44.
is supported. A conductive wire 46 is drawn out from the step motor 6 and connected to an electronic control device to be described later.

As shown in FIG. 2, the lower end surface 2b of the carburetor 2 is joined to the mounting surface 42 of the intake manifold described above, while an air purifier (not shown) is attached to the upper end surface 2a. The primary air passage 4 and the secondary air passage 3 communicate with the opening 4a and the opening 3a, respectively.

A known throttle valve is supported by a valve shaft 21 inside the primary air passage 4 in order to control the amount of mixture or fuel taken into the cylinders of the engine. The opening degree of the throttle valve is controlled by a step motor 6 which is driven in relation to the amount of depression of the accelerator pedal 31. The fuel lever 23 and the throttle valve connected to the valve shaft 21 are rotationally biased to the idle position by a return spring (not shown).

According to the present invention, the drive lever 22 is freely rotatably supported on the valve shaft 21, and the adjustment bolt 14, which is a protrusion that is screwed and supported on the protrusion 22a formed at the tip of the drive lever 22, is attached to the fuel lever 23. Projection piece 23a
It is said that it is possible to collide with Pin 10 to drive lever 22
One end of the link 9 is connected by this. The other end of the link 9 is connected by a pin 8 to an arm 7 connected to the main shaft 5 of a step motor 6 containing a reduction gear.

Control signals corresponding to the amount of depression of the accelerator pedal 31, the idle position of the throttle valve, the fully open position of the throttle valve, the start of the vehicle, the gear change state of the transmission, etc. are applied to the step motor 6 from the electronic control unit 30. For this purpose, the accelerator pedal 31 is equipped with an accelerator sensor 32 consisting of a potentiometer that detects the amount of depression as a change in resistance, and the change in resistance of the potentiometer is inputted to the electronic control unit 30 as a digital signal by an AD converter 33. . Further, signals corresponding to the start of the vehicle, the shift position of the transmission, the engagement and disengagement of the clutch mechanism, etc. are inputted to the electronic control unit 30 as digital signals.

In order to detect the idle position and the fully open position of the throttle valve, a fan-shaped cam 20 is formed integrally with the drive lever 22, and on both ends of the cam 20 there are recesses (or protrusions) as actuating parts for opening and closing the switch 16, which will be described later. good) 20a and 20b are provided. A bell crank 18 having a roller 19 that engages with a cam 20 is supported by a support shaft 17 on a bracket 50 fixed to an intake manifold 41 shown in FIG.

A switch 16 is supported by a bolt 51 on a bracket 50, and an end of a bell crank 18 is extended opposite a contact 16a of the switch 16. The bell crank 18 has a spring 52 wound around the support shaft 17.
(FIG. 3), the roller 19 is urged to rotate clockwise in FIG. 2, and the roller 19 is engaged with the cam 20.

Next, the operation of the fuel control device for an internal combustion engine according to the present invention will be explained. The resistance characteristic of the accelerator sensor 32 is that, as shown by the line 61 in FIG. 4, the resistance value is highest at the release position of the accelerator pedal 31 (return position due to the spring), and the resistance value is highest at the position where the accelerator pedal 31 is fully depressed. is set in advance to be 0. This only requires that the resistance of the accelerator sensor 32 change within the operating range of the accelerator pedal 31, and does not require strict adjustment. During normal driving, the accelerator pedal is 3.
The step motor 6 is driven in proportion to the change in resistance of the accelerator sensor 32 caused by the operation 1, and the opening degree of the throttle valve is controlled.

Now, when the accelerator pedal 31 is slightly depressed from the release position, the step motor 6 is driven by a signal from the electronic control unit 30 in the direction of fully opening the throttle valve. That is, the drive lever 22 is rotated counterclockwise about the valve shaft 21 in FIG.
The protruding piece 23a is pushed and the fuel lever 23 is rotated. When the throttle valve is slightly rotated from the idle position in the opening direction by the fuel lever 23 and the roller 19 rides up from the recess 20a of the cam 20 to the protrusion,
The bell crank 18 is rotated counterclockwise about the support shaft 17, and the contact 16a is closed.

The operation signal of the switch 16 at this time is input to the electronic control device 30. That is, as shown in FIG. 4, the number of steps of the step motor 6 until the switch 16 closes at the operating point S1 is stored in the memory of the electronic control unit 30 as an idle position signal. As the resistance value detected by the accelerator sensor 32 changes from the resistance value R1 at the idle position to the resistance value R2 at the fully open position, the step motor 6 is driven by the number of steps proportional to the resistance change.
The opening of the throttle valve is increased.

When the accelerator pedal 31 is fully depressed, the fuel lever 23 is rotated counterclockwise together with the valve shaft 21 by the drive lever 22 connected to the step motor 6, and the roller 19 that abuts the cam 20 is moved into the recess 20b. When it falls, contact 16 of switch 16
a is opened. The operation signal of the switch 16 at this time is input to the electronic control device 30, and the electronic control device 3
The step signal applied from 0 to the step motor 6 is stopped, and the step motor 6 is no longer rotated and is held at that position.

In this way, the rotation angle of the step motor 6 is controlled in proportion to the amount of depression of the accelerator pedal between the operating point S1 and the operating point S2 of the switch 16 which detects the idle position and the fully open position of the throttle valve.

According to the present invention, the fuel lever 23 that interlocks the throttle valve and the drive lever 22 that interlocks with the step motor 6 are independent, and the step motor 6 rotates the drive lever 22 at the same time as the accelerator pedal 31 is depressed. When activated, the fuel lever 23 is pushed by the drive lever 22 and rotated, opening the throttle valve. On the other hand, when the automatic throttle mechanism or fuel increase mechanism operates during a cold start, only the fuel lever 23 turns the fuel. Since the step motor is rotated in the increasing direction, the normal operation of the step motor is not disturbed.

Furthermore, when the throttle valve leaves the idle position, the signal value (step number) given to the step motor 6 is memorized, and the step number is determined based on the difference between this signal value and the subsequent detection value (signal value) of the accelerator sensor 32. Since the rotation angle of the motor 6 is controlled, even if the resistance characteristics of the potentiometer as the accelerator sensor 32 vary, the idle position of the throttle valve does not change. Therefore, it is not necessary to set the initial positions of the accelerator sensor 32 and the accelerator pedal 31 with great precision, making assembly very easy.

The deviation (play) between the idle position of the throttle valve and the operating point S1 of the switch 16 can be easily adjusted using the adjustment bolt 14 as necessary.

In the above-described embodiments, the fuel control member is a throttle valve of a carburetor. However, the present invention also applies to a fuel injection pump in which the control lever is actuated by the drive lever 22. If so, similar effects can be obtained.

[Effects of the invention] As described above, the present invention fixes and supports the fuel lever on the shaft that connects the fuel control member, supports the drive lever in a freely rotatable manner, and uses a spring to rotationally bias the fuel lever to the idle position. The projecting piece of the fuel lever is biased against the projecting piece of the drive lever, and an actuating part is provided on the disc cam connected to the fuel lever to close the switch at the idle position of the fuel control member and open the switch at the maximum fuel amount position. , is equipped with an electronic control device that sends a signal corresponding to a change in resistance of a potentiometer that detects the amount of depression of the accelerator pedal to the step motor that drives the drive lever in the closing operation range of the switch, so that the step motor can increase fuel. When the step motor is driven in the fuel direction, the fuel lever is rotated by being pushed by the drive lever, and the fuel control member is rotated in the fuel increasing direction.When the step motor is driven in the fuel decreasing direction, the fuel lever is rotated. It is rotated following the drive lever by the force of the spring. Therefore, the following effects can be obtained.

(a) Even if the position of the fuel control member is adjusted by directly operating the fuel lever, for example by an automatic chock mechanism, the operation of the step motor is not hindered, and the fuel control member is controlled in response to the surrounding conditions. It is possible to do so.

(b) There is no need for strict initial settings regarding the correspondence between the accelerator pedal and the potentiometer as an accelerator sensor, and even if the characteristics of the accelerator sensor change over a long period of use, the control accuracy will not change.

(c) Since the drive lever that interlocks with the step motor and the fuel lever that interlocks the fuel control member are coaxially supported, the overall configuration can be made compact.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing how the fuel control device for an internal combustion engine according to the present invention is attached to the intake manifold, Fig. 2 is a front view of the control device, Fig. 3 is a side view of the control device, and Fig. 4 FIG. 2 is a diagram illustrating the operating characteristics of the control device. 2... Carburetor, 6... Step motor, 7...
Arm, 9...Link, 16...Switch, 16a...
...Contact, 17...Spindle, 18...Bell crank,
20...Cam, 21...Valve shaft, 22...Drive lever, 22a, 23a...Protrusion piece, 23...Fuel lever, 31...Accelerator pedal, 32...Accelerator sensor.

Claims (1)

[Scope of utility model registration request] A fuel lever is fixedly supported on a shaft that connects the fuel control member, and a drive lever is freely rotatably supported, and a protrusion of the fuel lever is attached to a protrusion of the drive lever by a spring that biases the fuel lever to rotate to an idle position. an actuating portion is provided on a disk cam connected to the fuel lever, which closes the switch at the idle position of the fuel control member and opens the switch at the maximum fuel amount position;
The internal combustion engine is characterized by comprising an electronic control device that sends a signal corresponding to a change in resistance of a potentiometer that detects the amount of depression of the accelerator pedal to a step motor that drives the drive lever in the closing operation range of the switch. Engine fuel control system.