JPH04347340A - Inlet air quantity controller for engine - Google Patents

Abstract

PURPOSE:To install a phasic relationship between a throttle valve and an accelerator pedal alterably as securing their mechanical connection as well as to constitute such a mechanism as preventing a sudden change in engine power at the time of failing in a compact manner. CONSTITUTION:This constoller is made up of installing a phasic regulating means 15 by means of an ultrasonic motor or the like for setting a phasic relationship between an accelerator pedal 17 and a throttle valve 12 to be alterable only in the throttle closing direction at the time of current-energization but locking it at the time of current cutting, together with a throttle mechanism connecting the throttle valve 12 and the accelerator pedal 12 mechanically.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to an engine intake air amount control device in which a mechanism that can electrically control the intake air amount is interposed in the middle of a throttle mechanism that mechanically connects a throttle valve and an accelerator pedal. It is related to.

0002

[Background Art] Conventionally, engine intake air amount control devices have been used to control the opening of the throttle valve in response to the operation amount of the accelerator pedal, constant speed driving control (auto cruise control) that keeps the vehicle speed constant, and wheel slip amount. In order to perform traction control that maintains the engine in a predetermined state, and correction control of the driving feeling that changes the throttle characteristics according to changes in accelerator operation, etc., the mechanical connection between the throttle valve of the intake system and the accelerator pedal is Lose the link,
A known technique is to open and close this throttle valve by driving an actuator in accordance with the amount of accelerator operation, thereby increasing the degree of freedom in its opening and closing characteristics.

However, when the amount of intake air is electrically controlled by the actuator as described above, if a failure occurs in the drive system for opening and closing the throttle valve by this actuator, it becomes impossible to adjust the amount of intake air and the engine rotation slows down. Because there is a risk of the vehicle running out of control, a technology has been developed that maintains the mechanical link between the accelerator pedal and the throttle valve, allowing the throttle valve to return to the fully closed state even in the event of a failure in which electrical control becomes impossible. , for example, JP-A No. 6
It is publicly known as seen in Japanese Patent No. 3-208632.

0004

[Problem to be Solved by the Invention] In order to perform the above-mentioned auto cruise control, traction control, etc., it is desirable to easily configure the throttle valve opening/closing mechanism with a small number of actuators, while also controlling the throttle opening in the event of a system failure. It has become difficult to avoid sudden changes and ensure backup functions.

In other words, if the throttle valve and the accelerator pedal are completely separated and the throttle opening is controlled by electrical means, the throttle can be controlled by a single actuator. However, in this case, if a failure occurs in the control system of the actuator and the control becomes uncontrollable, the throttle valve suddenly closes from its previous opening position, so it is possible to prevent the engine from running out of control. However, the engine output changes rapidly in response to this throttle change, giving the driver a sense of discomfort. Additionally, there is a possibility of a failure in which the throttle valve remains open, and in this case, there is a risk of the engine running out of control. Therefore, it is necessary to install multiple actuators for backup, or to connect the throttle valve and accelerator pedal. However, installing multiple actuators poses major problems in terms of cost and weight, and it is desired to have a reliable backup function with a simple mechanism.

In view of the above circumstances, the present invention has been developed to ensure mechanical connection between the throttle valve and the accelerator pedal while making it possible to change the phase relationship between the two, and to provide a compact mechanism for preventing sudden changes in engine output in the event of a failure. An object of the present invention is to provide an intake air amount control device for an engine configured as follows.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the engine intake air amount control device of the present invention is provided with a throttle mechanism that mechanically connects a throttle valve and an accelerator pedal, and the throttle mechanism is provided with an accelerator pedal. A phase adjustment means is provided that can change the phase relationship between the pedal and the throttle valve only in the closing direction of the throttle valve, and the phase adjustment means is activated by energization and fixes the phase relationship in the current state when the energization is cut off. It is composed of

[0008] The phase adjustment means comprises an ultrasonic motor comprising two plates, a biasing means for pressing both plates with a predetermined pressure force, and an excitation means for applying ultrasonic vibrations to the plates. Can be done.

[0009] Furthermore, the phase adjustment means is provided with a restriction means for restricting operation in the throttle valve opening direction, and further includes an actuator for operating the throttle valve in the opening direction on the accelerator pedal side than the phase adjustment means. It is preferable to do so.

0010

[Function and Effect] In the engine intake air amount control device as described above, when the throttle control is simply performed according to the amount of accelerator operation, the phase adjustment means is in a stopped state and does not work in conjunction with the operation of the accelerator pedal. The throttle valve is mechanically opened and closed. Furthermore, when power is applied to the phase adjustment means to perform auto cruise control, traction control, correction control for driving feeling, etc., this phase adjustment means controls the throttle opening only in the direction of reduction in order to obtain a predetermined amount of intake air. , to obtain predetermined characteristics. In addition,
The throttle opening is corrected in the direction of increase by the driver operating the accelerator pedal in response to insufficient output.

[0011] When a failure occurs, the power to the phase adjustment means is cut off, and the phase adjustment means fixes the phase relationship between the accelerator pedal and the throttle valve in the current state, thereby adjusting the throttle valve in response to the opening/closing operation of the accelerator pedal. At that time, the phase adjustment means operates only in the valve closing direction, so that when the accelerator pedal is released, the throttle valve always returns to the fully closed state, preventing the engine from running out of control. It does not cause fluctuations such as the throttle valve closing suddenly, and there is no discomfort to the driver due to sudden changes in engine output, and good driving performance can be maintained.Moreover, the compact mechanism with few actuators reduces costs. This is advantageous in terms of weight.

[0012] Furthermore, the regulating means regulates the operation of the throttle valve in the opening direction, and prevents the throttle valve from opening in the opening direction due to intake negative pressure, thereby improving safety. moreover,
In the case of auto cruise control, etc., an actuator opens the throttle valve to open the throttle by a predetermined amount, eliminating the need to operate the accelerator pedal, and reducing the opening from this opening using a phase adjustment means to the predetermined opening. It is something to be adjusted. Furthermore, safety is improved by notifying the driver of the control to the opening side, and backup in the event of a runaway can be provided by the phase adjustment means.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration diagram of an engine intake air amount control device in one embodiment.

A throttle valve 12 is interposed in an intake passage 11 that supplies intake air to the engine body (not shown), and an ultrasonic motor as a phase adjustment means 15 is installed on a valve shaft 13 of the throttle valve 12. Valve shaft 1 of ultrasonic motor 15
The drum 16 on the opposite side from the accelerator pedal 1 has one end.
The other end of the accelerator wire 18 connected to 7 is connected,
A throttle mechanism is configured to mechanically connect the throttle valve 12 and the accelerator pedal 17.

The ultrasonic motor 15 has two plates, a first plate 21 (hereinafter referred to as rotor) and a second plate 22 (hereinafter referred to as stator), as shown in FIG. 2, although the detailed structure will be described later. and both plates 21, 22
a biasing means 23 (disc spring) for pressing with a predetermined pressure force;
It consists of an excitation means 24 (drive circuit) that applies ultrasonic vibration to the stator 22, and when activated by energization, the phase relationship between the accelerator pedal 17 and the throttle valve 12 can be changed and adjusted only in the closing direction of the throttle valve 12. . The operation of the ultrasonic motor 15 is controlled based on a control signal from the control unit 20, and when the ultrasonic motor 15 is not energized, the ultrasonic motor 15 is in a fixed state. , the throttle valve 12 opens and closes mechanically in conjunction with the operation of the accelerator pedal 17.

The ultrasonic motor 15 is also provided with a regulating means 27 for regulating the operation of the throttle valve in the opening direction so that the throttle valve 12 does not open more than the throttle opening corresponding to the operation amount of the accelerator pedal 17. We are prepared. Furthermore, an auto-cruise actuator 28 is installed that operates the drum 16 side of the ultrasonic motor 15 in the throttle opening direction so as to operate the accelerator wire 18 in the valve opening direction. That is, the locking member 29 is attached to the rotor 21.
is attached to the drum 16 (stator 22), and a stopper 30 is attached to the drum 16 (stator 22), and a locking member 29 is arranged so as to be able to come into contact with the stopper 30 from the valve closing side. Further, the auto-cruise actuator 28 is arranged so as to operate the stopper 30 in the valve-opening direction when activated.

To explain the configuration of the ultrasonic motor 15 in detail, a stator 22 made of an elastic body 22a and a piezoelectric body 22b is disposed adjacent to the drum 16, and the stator 22 is opposite to the drum 16. Slider 21 on the side
A rotor 21 made of a friction material 21b and a friction material 21b is disposed, and the rotor 21 is pressed against a stator 22 by the biasing force of a disc spring 23, and the stator 22 is pressed against the drum 16. The shaft to which the rotor 21 is attached serves as a valve shaft 13 that passes through the intake passage 11, and a throttle valve 12 is installed therein.On the other hand, the stator 22 and the drum 16 are arranged on the accelerator side shaft 31, and the ultrasonic motor 15 When not operating (current cut), the drum 16, stator 22, and rotor 21 rotate together by the disc spring 23.

In the stator 22, a piezoelectric material 22b (piezoelectric ceramic) which is polarized and divided into half wavelengths is bonded to an excitation elastic material 22a. The same piezoelectric material 22b is adhered to the remaining half with a 1/4 wavelength shift and is installed in a predetermined arrangement. In addition, a small electrode is provided in a part of the piezoelectric body 2 which is excited.
The voltage generated by the elastic body 22b is taken out and the frequency is fed back to the drive circuit 24 (excitation circuit), so that even if the resonance point of the elastic body 22a shifts due to temperature or load, the excitation follows it.

A tooth-shaped notch is provided on one side of the elastic body 22a to amplify and transmit the excitation to the rotor 21. This rotor 21 is fixed to the valve shaft 13, and has an elastic body 22a.
A friction material 21b that generates torque is adhered to the surface in contact with. Further, the contact pressure between the stator 22 and the rotor 21 is applied by the disc spring 23, and the contact pressure between the stator 22 and the rotor 21 is increased by the disc spring 23.
A high frequency oscillation power source by a drive circuit 24 is connected to the piezoelectric body 22b.

To explain the operating principle, the standing wave generation mechanism is that when an alternating current voltage is applied to the polarized piezoelectric material 22b, vibrations of expansion and contraction are generated continuously, and the elasticity attached to the piezoelectric material 22b The body 22a includes a piezoelectric body 22
Deflections occur alternately, with the extended side being a valley and the contracted side being a peak, and a standing wave that repeatedly moves up and down at the same location is generated in the elastic body 22a. Furthermore, the elastic body 22a
By attaching piezoelectric bodies 22b that are polarized in the direction of thickness and shifted by 1/4 wavelength to The waves interfere with each other and are combined to form a traveling wave.

[0021] The traveling wave formed on the surface of the elastic body 22a is propagating at the speed of sound, and the mass points on the surface are performing elliptical motion in the opposite direction to the traveling direction of the wave. The rotor 21 (moving body) that is pressed against the surface of the elastic body 22a contacts the elastic body 22a at its apex,
Due to mutual frictional force, it moves at a predetermined vibration speed in the opposite direction to the traveling wave, and the output shaft, that is, the valve shaft 13, rotates with respect to the stator 22 (drum 16) in the direction in which the throttle valve 12 closes.

Further, in order to detect the operating state of the ultrasonic motor 15 and perform feedback control, the drum 1
An accelerator sensor 33 that is a potentiometer that detects the amount of rotation (accelerator opening) of 6 is installed, and a throttle sensor 34 that is a potentiometer that detects the throttle opening is installed on the valve shaft 13. These signals are output to the control unit 20 and used to control the ultrasonic motor 15.

The drive control of the ultrasonic motor 15 is performed by outputting a control signal from the control unit 20 to the drive circuit 24, as shown in FIG. A phase adjustment signal from the calculation section 25 is output. This control amount calculation unit 25 receives detection signals such as accelerator opening, engine rotation speed, vehicle speed, and wheel speed via an input interface circuit 38, and calculates a target throttle opening based on traction control and auto cruise control. When this target throttle opening becomes smaller than the accelerator opening corresponding to the operation amount of the accelerator pedal 17, the ultrasonic motor 15 is energized so that the actual throttle opening becomes the target throttle opening. The throttle opening is controlled by outputting a signal that drives the throttle opening in the closing direction.

The control unit 20 also has an auto-cruise command section 26, which inputs signals such as a main operation signal, a vehicle speed set signal, a brake signal, and a vehicle speed to an interface circuit 38.
When performing auto-cruise control, based on the signal received through the auto-cruise control and determining the conditions for establishing auto-cruise control, a command signal is output to drive the auto-cruise actuator 28, while stopping the auto-cruise control. In this case, control is performed to stop outputting the command signal and stop driving the autocruise actuator 28.

Furthermore, the control unit 20 is equipped with a fault diagnosis circuit 37, and this fault diagnosis circuit 37 detects that the actual throttle opening in the control of the throttle valve 12 does not approach the target throttle opening even after a predetermined period of time has elapsed. When a failure occurs, a signal is output to the drive circuit 24 to cut off the power to the ultrasonic motor 15.

Next, the failure diagnosis control processing by the control unit 20 will be explained based on the flowchart of FIG. In this fault diagnosis subroutine, first,
In step S1, it is determined whether or not a drive signal is being output to the ultrasonic motor 15. If the determination is YES and drive control of the ultrasonic motor 15 is being performed, a fail flag (described later) is flagged in step S2. Determine whether F is set to 1. If the failure diagnosis has not been performed, the fail flag F is reset to 0, so the process proceeds to step S3, where the control amount calculation section 25 performs a reduction operation by driving the ultrasonic motor 15 for the accelerator opening. The target throttle opening TVo and the actual throttle opening TV measured by the throttle sensor 34 are input.

Then, in step S4, the deviation ΔTV between the target throttle opening TVo and the actual throttle opening TV is determined.
is calculated, and it is determined in step S5 whether the deviation ΔTV is greater than or equal to a certain value A. If this determination is YES and the deviation is greater than or equal to a certain value A, it is determined in step S6 whether this state has continued for a certain period of time or more, and if a continued failure occurs, a fail flag F is set in step S7. At the same time, energization is cut off in step S9. Based on the setting of the fail flag F, the energization cut is continued if the determination in step S2 is YES. If the determination in step S1 is NO and no motor drive command has been issued, the fail flag F is reset in step S8 when the determination in step S5 or S6 is NO and normal operation is performed.

[0028] In the event of the above failure, auto-cruise control is disabled, so the failure diagnosis circuit 37 outputs a stop signal to the auto-cruise command unit 26, thereby outputting a signal to stop the operation of the auto-cruise actuator 28. be.

As a result of the above processing, when auto cruise control or traction control is not performed during normal operation, that is, when the ultrasonic motor 15 is not energized and is not driven, the ultrasonic motor 15 is Both plates 21 and 22 are pressed together and rotated together by the biasing force of a disc spring 23, and are mechanically linked via an accelerator wire 18 in response to the operation of the accelerator pedal 17 to open and close the throttle valve 12. will be held. In addition, when the accelerator opening is opened while driving on a slippery road surface and the wheels slip, the target throttle opening calculated by the control amount calculation unit 25 as a result of traction control may be changed to the actual throttle opening. become smaller,
When reducing the throttle opening, a drive signal is output to the ultrasonic motor 15 to move the rotor 21 to the throttle valve 12.
Operates in the closing direction. At this time, the restricting means 27 prevents the throttle valve 12 from opening in the opening direction beyond the accelerator opening.

Furthermore, when performing auto cruise control, the actuator 28 is operated to open the throttle by a predetermined amount, and from this state the target throttle is adjusted according to the deviation between the two so that the actual vehicle speed becomes the set vehicle speed. The opening degree is calculated, and the throttle valve 12 is driven to the target throttle opening degree by driving the ultrasonic motor 15.

On the other hand, while the throttle opening is controlled to the target throttle opening by driving the ultrasonic motor 15, the actual throttle opening does not match the target throttle opening for a long time, resulting in a poor control state. When a failure occurs, the power supply to the ultrasonic motor 15 is cut off. Accordingly, the first and second plates 21 and 22 of the ultrasonic motor 15 become fixed, the throttle valve 12 opens and closes together with the accelerator pedal 17, and when the accelerator pedal 17 is returned, the throttle valve 12 is also fully closed. This is to prevent the engine from running out of control.

In addition, at this time, the ultrasonic motor 15 becomes stuck due to the power cut, and first the throttle valve 12 is mechanically connected to the accelerator pedal 17 while keeping the current phase state, so that sudden throttle opening is prevented. The opening degree corresponds to the operation of the accelerator pedal 17 without causing a decrease in the amount of the accelerator pedal 17, and the output fluctuation is small and the operation feeling is good.

[Brief explanation of drawings]

[Fig. 1] Overall configuration diagram of an engine intake air amount control device of the present invention.

[Fig. 2] A perspective view of the main parts for explaining the operation of the phase adjustment means.

[Figure 3] Block diagram of control unit

[Figure 4] Main part flowchart diagram for explaining the processing of the control unit

[Explanation of symbols]

11 Intake passage 12 Throttle valve 15 Phase adjustment means (ultrasonic motor) 16
Drum 17 Accelerator pedal 18 Accelerator wire 20 Control unit 21 First plate (rotor) 22 Second plate (stator) 23 Biasing means (disc spring) 24 Vibration means (drive circuit) 25 Controlled amount calculation section 26 Auto cruise command section 27 Regulating means 28 Actuator 29 Locking member 30 Stopper 34 Throttle sensor 37 Failure diagnosis circuit

Claims (4)

[Claims] 1. A throttle mechanism that mechanically connects a throttle valve and an accelerator pedal is provided, and the throttle mechanism is provided with a phase adjustment means that can change the phase relationship between the accelerator pedal and the throttle valve only in the closing direction of the throttle valve. 1. An intake air amount control device for an engine, characterized in that the phase adjustment means is actuated by energization, and is configured to fix the phase relationship in the current state when energization is cut off. 2. The phase adjustment means comprises an ultrasonic motor comprising two plates, a biasing means for pressing both plates with a predetermined pressure force, and an excitation means for applying ultrasonic vibrations to the plates. The intake air amount control device for an engine according to claim 1, characterized in that: 3. The intake air amount control device for an engine according to claim 1, wherein the phase adjusting means is provided with a regulating means for regulating operation in the opening direction of the throttle valve. 4. The intake air amount control device for an engine according to claim 1, further comprising an actuator for operating in a throttle opening direction closer to the accelerator pedal than the phase adjustment means.