JPH04298664A - Intake air quantity regulating device for internal combustion engine - Google Patents

Abstract

PURPOSE:To remarkably improve a mounting property by utilization of a small sized and inexpensive PM type stepping motor by providing a throttle valve to open/close a main intake passage introducing intake air to an internal combustion engine, and a bypass flow regulating valve to open/close a bypass intake passage. CONSTITUTION:A throttle valve 16 is opened or closed with a stepping motor 20. An intake air quantity to a main intake passage 22 is increased or decreased corresponding to increase or decrease of the intake air quantity necessary for an internal combustion engine 18. While follow-up delay is not generated in the stepping motor 20, a bypass flow regulating valve 12 is opened or closed in the relation corresponding to increase or decrease of a necessary intake air quantity with an actuator 10. When the necessary intake air quantity is suddenly changed to decrease, follow-up delay is generated in the stepping motor 20. Then, it is detected by a follow-up delay detecting means 4, the actuator 10 begins to be controlled following to follow-up delay compensation control condition 8a.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for regulating the amount of air taken into an internal combustion engine. In particular, the present invention relates to a device that uses a stepping motor to open and close a throttle valve for adjusting the amount of intake air.

(Background of the Invention) In order to optimally control the opening degree of a throttle valve according to the operating condition of an internal combustion engine,
A structure in which the throttle valve is opened and closed by a stepping motor has been developed, and is published in Japanese Patent Application Laid-Open No. 2-42150, Japanese Patent Application Laid-Open No. 63-143359, and the monthly "Internal Combustion Engine" No. 2.
It is disclosed in Volume 8, No. 2, page 54 et seq. in this case,
Stepping motors are required to (1) open and close the throttle valve at a sufficiently high speed to quickly change the operating state of the internal combustion engine, that is, have a small follow-up delay, and (2) accurately control the amount of intake air. (3) It must be possible to adjust the opening of the throttle valve in small steps, that is, the resolution must be small, and (3) it must have enough torque to open and close the throttle valve against the frictional force of the throttle shaft and the force due to the intake air flow. It will be done.

[0003] In order to make the resolution of the throttle valve opening finer or to increase the torque, a speed reduction mechanism may be interposed between the throttle valve and the stepping motor. However, when a speed reduction mechanism is used, the opening/closing speed of the throttle valve decreases and the follow-up delay becomes large.

0004

2. Description of the Related Art The throttle body disclosed in the above-mentioned "Internal Combustion Engine", Vol. 28, No. 2, pp. 54-56 uses a hybrid stepping motor that has excellent followability, resolution, and torque characteristics. Also, JP-A-2-4
In the techniques described in Japanese Patent Laid-open No. 2150 and Japanese Patent Laid-Open No. 63-143359, the driving method of the stepping motor is devised to ensure high-speed response.

[0005]

However, the hybrid stepping motor itself is expensive, and it is preferable to use a cheaper and smaller PM stepping motor. However, PM type stepping motors have problems in followability, resolution, and torque characteristics, and cannot be put to practical use. Furthermore, even if a hybrid stepping motor is used, tracking performance, resolution,
If the requirements for torque characteristics etc. become higher, larger and more expensive motors will have to be used, which cannot be said to be a perfect solution in terms of mounting ease and cost.

[0006] Furthermore, as described in the above-mentioned Japanese Patent Laid-Open Publication No. 2-42150 and Japanese Patent Laid-Open No. 63-143359, a method is adopted in which the driving method of the stepping motor is devised to ensure high-speed response. There is a limit to its responsiveness, and it cannot be said to be a sufficient solution. Particularly when the target number of steps changes frequently or when the stepping motor needs to be reversed quickly, the occurrence of a follow-up delay cannot be avoided no matter how devised the drive system is. Techniques for opening and closing the throttle valve using actuators other than stepping motors have also been proposed (for example, Japanese Patent Laid-Open No. 61-43
According to this method, the opening degree of the throttle valve cannot be adjusted as accurately as when using a stepping motor, and this method is also not a sufficient solution.

Therefore, the present invention aims to develop a technique that improves the followability of the intake air amount adjusting device as a whole by compensating for the drawback of the stepping motor, which has a problem with high-speed followability, by other means. did. According to the present invention, it is possible to secure necessary followability, resolution, and torque characteristics while using an inexpensive and small PM stepping motor. Furthermore, when a hybrid stepping motor is used, faster response can be ensured without increasing the size of the motor. Furthermore, no special innovation is required for the stepping motor drive method, and a simple and inexpensive stepping motor controller is sufficient.

[0008]

[Means for Solving the Problems] To this end, in the present invention,
The intake air amount adjusting device, the concept of which is schematically shown in FIG. a stepping motor 20 that bypasses the throttle valve 16 and guides a portion of the intake air; a bypass flow rate adjustment valve 12 that opens and closes the bypass intake passage 14; an actuator 10 that opens and closes the bypass flow rate adjustment valve; The intake air amount increase/decrease instruction means 2 instructs to increase or decrease the intake air amount required by the internal combustion engine 18; the follow-up delay detection means 4 detects the occurrence of a follow-up delay of the stepping motor 20; A stepping motor controller 24 correspondingly increases or decreases the number of steps of the stepping motor 20, and when a follow-up delay is not detected by the follow-up delay detection means 4, the actuator 10 increases or decreases in response to an instruction from the intake air amount increase/decrease instruction means 2. According to the requested amount corresponding control mode 8b which controls the operation of the intake air amount increase/decrease instructing means 2, when a follow-up delay is detected by the follow-up delay detection means 4, the intake air amount increase/decrease instruction means 2 is operated to compensate for the influence of the follow-up delay. According to the control mode 8a, an intake air amount adjusting device for an internal combustion engine has been created, which has an actuator controller 8 that controls the operation of the actuator 10 (corresponding to claim 1).

The bypass flow rate regulating valve 12 may be a butterfly type valve that rotates to open and close the flow path, or a plunger or the like that moves back and forth to open and close the flow path. The actuator 10 is preferably a solenoid coil whose duty ratio is controlled or a rotary solenoid, but other actuators such as a motor may also be used. In addition, the intake air amount increase/decrease instruction means 12 may be one that indicates the amount operated by the operator, such as an accelerator operation amount detection sensor, or may be used to maintain the internal combustion engine at a constant rotation speed. The target rotation speed and the actual rotation speed may be compared and instructions may be given to increase or decrease the intake air amount.

[0010] In addition, to the configuration corresponding to claim 1, a means 6 for determining whether or not the internal combustion engine 18 is operating in a substantially steady state is added, and when the internal combustion engine 18 is operating in a steady state, the actuator 10 is activated. Control mode 8 to fix at that position
It is preferable that c is added to the actuator controller 8 (corresponding to claim 2).

[0011]

According to the first aspect of the invention, the stepping motor 20 opens and closes the throttle valve 16, whereby the amount of intake air in the main intake passage 22 is increased or decreased in accordance with the increase or decrease in the amount of intake air required by the internal combustion engine 18. . In addition, when the required intake air amount is constant or changes slowly and there is no follow-up delay in the stepping motor 20, the bypass flow rate adjustment valve 12 is also controlled by the actuator 10 to increase or decrease the required intake air amount. They are opened and closed in corresponding relationships. That is, when the throttle valve 16 is closed, the bypass flow rate adjustment valve 12 is also closed, and when the throttle valve 16 is opened, the bypass flow rate adjustment valve 12 is also closed.
can also be opened. The total intake air amount taken into the internal combustion engine 18 is increased or decreased in accordance with the increase or decrease in the required intake air amount. If a phenomenon such as a sudden change in the required intake air amount occurs, the stepping motor 20 will be delayed in following. Then, this is detected by the follow-up delay detection means 4, and the actuator 10 starts to be controlled according to the follow-up delay compensation control mode 8a.

According to this control mode 8a, the actuator 10 is operated more than the instruction from the intake air amount increase/decrease instruction means 2. For example, when the intake air amount increase/decrease instructing means 2 gives an instruction to rapidly increase the intake air amount, the actuator 10 is opened greatly and rapidly at a speed greater than that corresponding to the request for increasing the intake air amount. For this reason, a follow-up delay occurs in the stepping motor 20, and the fact that the main intake air amount does not increase quickly is compensated for by a sudden increase in the bypass intake air amount.

In this case, when the intake air amount rapid increase signal is generated, the throttle valve 16 is closed and the bypass flow rate regulating valve 12 is also closed. Therefore, there is a margin in the operating range of the bypass flow rate regulating valve 12, and the actuator 10 is not prevented from operating rapidly and greatly as described above.

A completely opposite effect also occurs when the intake air amount is suddenly increased; a delayed change in the main intake air amount is compensated for by a sudden decrease in the bypass intake air amount, and the total intake air amount is suddenly reduced.

According to the second aspect of the invention, in addition to this, it is determined whether or not the internal combustion engine 18 is operating in a substantially steady state. The actuator 10 is locked at that position while operating in a steady state. The intake air amount is finely adjusted by finely adjusting the throttle valve 16, and accurate intake air amount control by the stepping motor 20 is realized.

[0016]

[Embodiments] First Embodiment In this embodiment, the present invention is applied to a vehicle engine 18a. As shown in FIG. 2, intake air is introduced to the vehicle drive engine 18a through a main intake passage 22, and the main intake passage 22 is connected to the throttle valve 16.
is opened and closed. The throttle valve 16 is opened and closed by a PM type stepping motor 20 having a built-in speed reduction mechanism. This reduction mechanism is composed of a reduction gear train.

A throttle valve 1 is provided in the main intake passage 22.
A bypass intake passage 14 is formed to guide a part of the intake air to the engine 18a, bypassing the intake air 6. This bypass intake passage 14 is opened and closed by a bypass flow rate adjustment valve 12. The bypass flow rate adjustment valve 12 is of a butterfly valve type, and opens and closes the bypass intake passage 14 by rotating. This bypass flow rate adjustment valve 12 is rotated by a rotary solenoid 10. That is, this rotary solenoid 10 is used as an actuator that opens and closes the bypass flow rate regulating valve 12. The rotation angle of this rotary solenoid 22 is adjusted by adjusting the duty ratio, and when driven at a duty ratio of 100%, the bypass flow rate adjustment valve 12 is fully opened and driven at a duty ratio of 0%. When this happens, the bypass flow rate adjustment valve 12 is fully closed.

In this embodiment, an accelerator opening sensor 2a that detects the amount of depression of the vehicle-mounted accelerator pedal 1 is used as a means for instructing an increase or decrease in the amount of intake air. Figure 4,
As will be explained later in connection with 5 and 6, the stepping motor 20 and the actuator 10 are controlled based on the detected value of the accelerator opening sensor 2a. This control is EC
It is executed by U (electronic control unit) 26. That is, in this embodiment, the stepping motor controller 2
4 and the actuator controller 8 are constituted by the ECU 26. In addition, the ECU 26 also operates as a follow-up delay detection means 4 and a steady state determination means 6.

The ECU 26 has a configuration roughly shown in FIG. 3. A signal corresponding to the amount of depression of the accelerator pedal 1 from the accelerator opening sensor 2a is input to the level correction circuit 30 and amplified, and after being converted to a digital signal by the analog-to-digital converter 32, it can be input to the CPU 34. There is. Every time the crankshaft of the engine 18a reaches a predetermined rotation angle, a pulse wave is output from the crank angle sensor 19, which is waveform-shaped by a waveform shaping circuit 36 and then input to the CPU 34.

Connected to the CPU 34 are a ROM 38 for storing programs, map data, etc., and a RAM 40 for temporarily storing data. The CPU 34 processes the input data according to the procedure described later, and based on the processing result, sends a signal to the drive circuit 42 instructing the stepping motor 10 to rotate forward or reverse. Based on this, the drive circuit 42 generates a pulse wave that actually rotates the stepping motor 20 in the forward or reverse direction, and sends this to the stepping motor 20. The stepping motor 20 rotates one step forward when a pulse for forward rotation is sent, and rotates backward one step when a pulse for reverse rotation is sent.

Furthermore, the CPU 34 causes the drive circuit 44 to control the rotary solenoid actuator 1 based on the processing results.
A signal indicating the duty ratio to be given to 0 is sent. Based on this, the drive circuit 44 generates a pulse wave having a designated duty ratio, and transmits the pulse wave to the rotary solenoid 10.
send to The rotary solenoid 10 is rotated to an angle corresponding to the duty ratio of the sent pulse wave.

FIG. 4 shows the processing procedure executed by the control program 38a stored in the ROM 38. This process is performed in synchronization with the driving cycle of the stepping motor 20.

FIGS. 7 and 8 show the contents of the map data stored in the ROM 38, which shows the target number of steps (TSTEP) of the stepping motor 20 that is desired to be realized with respect to the amount of accelerator depression detected by the accelerator opening sensor 2a. )
and the target duty ratio (TD) given to the actuator 10.
UTY) is stored. As shown in FIG. 7, the amount of accelerator depression and the target number of steps are set in a non-linear relationship, providing good operability in a small intake air amount state. Further, as shown in FIG. 8, the target duty ratio is set in such a manner that the more the accelerator is depressed, the greater the duty ratio becomes, and the bypass flow rate regulating valve 12 is opened more widely.

In step S1 of FIG. 4, a target step number (T
STEP). Similarly, in step S2, the target duty ratio (T
DUTY). In step S3, the target number of steps (TSTEP) and the current number of steps are compared.

When there is a large difference between the target number of steps and the current number of steps, if the target number of steps is larger, the stepping motor 20 is
Sends a signal to open a step, and if the target number of steps is smaller, sends a signal to close one step (step S7
). In this way, the stepping motor 20 is controlled in step S7, and the main intake air amount is increased or decreased in a manner corresponding to the increase or decrease in the required intake air amount.

FIG. 9 shows how the main intake air amount changes due to this, and the main intake air amount is increased or decreased according to the characteristic curve L1 following the increase or decrease in the required intake air amount. Furthermore, if it is detected in step S3 of FIG. 4 that the target number of steps and the current number of steps are significantly different, that is, that a following delay has occurred in the stepping motor 20, the degree of the following delay is detected in step S8. In step S9, the duty ratio correction amount (XDIV) necessary to compensate for the deviation in intake air amount due to the follow-up delay is calculated. This correction amount XDIV is stored in the ROM 38 in advance in such a manner that the larger the follow-up delay, the larger the value. Then, the duty ratio is determined in step S10.
It is corrected to a value obtained by adding the correction amount XDIV calculated in step S9 to the target duty ratio calculated in step S2.

A characteristic line L2 in FIG. 9 shows the total intake air amount when both the number of steps and the duty ratio are adjusted to the target values. That is, the difference between the characteristics L2 and L1 is the bypass intake air amount, and since the duty ratio is adjusted according to the relationship shown in FIG. 8, the bypass intake air amount also increases as the accelerator depression amount increases.

This characteristic line L2 corresponds to the process in FIG. 4 when the duty ratio correction control in steps S8, S9, S10, etc. is not performed. On the other hand, L3 and L4 are the ones when the duty ratio correction control is performed in steps S8, S9, S10, etc.
The difference between the characteristic lines L3 and L2 or between L4 and L2 corresponds to the correction of the bypass flow rate due to the correction of the duty ratio. In other words, when the accelerator is suddenly depressed, the difference between the target number of steps and the actual number of steps is large, and the duty ratio is set to an even larger value than the relationship shown in FIG. 8, resulting in a sudden increase in the bypass flow rate as shown in characteristic L3. do. On the other hand, when the follow-up delay is resolved, the amount of correction of the duty ratio becomes smaller and approaches the characteristic of L2.

According to the process shown in FIG. 4, when the intake air amount is suddenly reduced, the duty ratio is further reduced in step S10 of FIG. 4, and as a result, as shown in the characteristic line L4 of FIG. The bypass intake air suddenly decreases and the delay in following the main intake air amount is compensated for. These are clearly shown in Figure 10. In the case of operating conditions where the required air amount changes suddenly as shown in Figure 10 (c), the bypass intake air amount changes as shown in Figure 10 (B). The delay in following the main intake air amount shown in FIG. 10(A) is compensated for.

In FIG. 10(A), T1 indicates a period in which the stepping motor 20 speeds up slowly, and T3 indicates a period in which it decelerates for reversal. It is illustrated that delays are inevitable. Figure 10(B)
L5 indicates the bypass intake amount when the duty ratio is controlled according to the relationship shown in FIG. 8, but as a result of this being corrected in steps S8, S9, and S10 in FIG. 4, the bypass intake amount becomes as shown in L6. It will be adjusted. Note that the sum of the main intake air amount L7 and the bypass intake air amount L6 closely matches the required intake air amount L8, confirming the usefulness of this embodiment.

[0031] In this way, steps S8, S9, S1
0, the actuator 10 is controlled so that the influence of the following delay of the stepping motor 20 is compensated for, and this corresponds to the following delay compensation control aspect 8a of the present invention. Note that step S3 in FIG. 4 has a function of detecting the occurrence of a follow-up delay of the stepping motor 20, as is clear from the above.

Next, a case will be explained in which the amount of depression of the accelerator pedal 1 is not changed rapidly. In this case, the stepping motor 20 is almost always maintained at the target step number TSTEP shown in FIG. 7 (this is maintained as a result of execution of step S6, which will be described later). Therefore, in step S3, the target step number and the current number of steps are determined to be approximately equal, and in step S4, the current target duty ratio (TDUTY, obtained in step S2) is determined.
and the duty ratio of the previous execution. Here, if the previous and current duty ratios are almost equal, step S5
is skipped and the previous duty ratio value is maintained. In other words, if the target duty ratio hardly changes, the engine 18a is operating in a steady state.
In this case, the duty ratio is not changed and is fixed at the same value, and the intake air amount is finely adjusted by the stepping motor 20 (step S6).

As is clear from this, it is determined whether or not the steady state is present in steps S3 and S4. Furthermore, in a steady state, a control mode in which the actuator 10 is locked is realized by skipping step S5. On the other hand, if the operating state of the engine 18a is changing even if it is gradual, step S5 is executed and the duty ratio is updated to the target duty ratio for the state. The intake air amount characteristic obtained by this process is the characteristic L2 in FIG. 9 described above.

5 and 6 show processing procedures for controlling the duty ratio, and the processing in FIG. 5 is interrupted and executed in synchronization with the basic cycle of the rotary solenoid actuator 10. This is executed at longer time intervals than the execution cycle of FIG. Step S11 is step S5 in FIG.
Or the duty ratio set in S10 is 100%
100
%, actuator 10 until the next execution cycle.
Continue to energize (step S13 is skipped and S14
).

If the duty ratio is found to be 0% in step S12, the actuator 10 is not energized (
Step S14 is not executed). In the intermediate case, the process in FIG. 6 is executed as an interrupt after a time corresponding to the duty ratio has elapsed since the first turn on (S
13). In this way, duty ratio control is executed.

Second Embodiment In this embodiment, the present invention is applied to an engine for a generator. Figure 11 shows the system configuration.
The accelerator pedal 1 and the accelerator opening sensor 2a are removed from the one shown in FIG. In this case, due to its nature as a generator, the engine 18a is controlled to rotate at a constant speed.

In step S20 of FIG. 12, the actual rotational speed (
This is to compare whether or not the rotation speed (detected by the signal of the crank angle sensor 19) matches the target rotation speed, and if they match, the processes of S23, S25, S28, and S29 are not executed. That is, the stepping motor is not rotated at this timing. Step S21 is to determine the degree of deviation of the engine rotational speed from the target, and if the deviation is small and there is no follow-up delay in the stepping motor 20, the duty ratio is controlled in accordance with the required amount in steps S23 to S26. Select the mode, and if a tracking delay occurs, step S30, S31, S32
Select the tracking delay compensation control mode.

[0038] If the actual rotation speed is lower than the target rotation speed with no follow-up delay occurring, step S23
Open the stepping motor 20 by one step. Also, the duty ratio is increased by a unit amount (S24). Conversely, if the rotational speed is too high, the stepping motor is closed by one step in step S25. Then, the duty ratio is decreased by a unit amount (S26). Here, step S22 corresponds to a means for instructing an increase or decrease in the intake air amount, and when the answer is YES, an increase is given, and when the answer is NO, a decrease is given, and the stepping motor and rotary actuator are opened and closed in response to this. It is. That is, the stepping motor and the rotary actuator are controlled in a manner that corresponds to an increase or decrease in the required intake air amount.

On the other hand, if the engine speed is significantly lower than the target speed, the answer in step S27 is YES, and the stepping motor is opened by one step in step S28.
). If the engine speed has increased significantly, the stepping motor is closed by one step in step S29. In these cases, that is, when a tracking delay occurs in the stepping motor 20 and the actual rotational speed deviates significantly from the target value, the duty ratio is corrected to compensate for this deviation in steps S30, S31, and S32. .

As a result of executing the processes shown in FIGS. 5 and 6 based on the duty ratio corrected in this manner, the bypass intake air amount is rapidly increased or decreased, and the engine speed is rapidly increased or decreased.

As described in detail above, according to this embodiment, the total intake air amount is quickly adjusted, and the responsiveness of the engine is improved. Moreover, at this time, the responsiveness of the stepping motor does not need to be very good.

[0042]

[Effects of the Invention] According to the present invention, the main intake air amount is finely and accurately controlled by the stepping motor, and when high-speed followability is required, the bypass intake air amount is rapidly adjusted to achieve high-speed followability. can be secured. At this time, the stepping motor itself does not need to be very fast. Therefore, a small and inexpensive PM type stepping motor can be used. This significantly improves the ease of mounting, and for example, it becomes possible to control the throttle valve of an engine for a small generator with a stepping motor. It is also advantageous in terms of cost, and the advantages of optimal control of valve opening by a stepping motor can be realized in various models.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing the concept of the present invention.

FIG. 2 is a configuration diagram of an example in which the present invention is applied to an on-vehicle engine.

FIG. 3 is a configuration diagram of the ECU in FIG. 2.

FIG. 4 is a diagram showing a processing procedure for realizing a first control mode.

FIG. 5 is a procedure diagram for duty ratio control.

FIG. 6 is a procedure diagram for controlling the duty ratio in conjunction with the process of FIG. 5;

FIG. 7 is a diagram showing the relationship between the target step number and the accelerator opening degree.

FIG. 8 is a diagram showing the relationship between target duty ratio and accelerator opening.

FIG. 9 is a diagram illustrating the effects obtained by the present invention.

FIG. 10 is a diagram illustrating the effects obtained by the present invention.

FIG. 11 is a configuration diagram of an example in which the present invention is applied to a generator engine.

FIG. 12 is a diagram showing a processing procedure for realizing a second control mode.

[Explanation of symbols]

ECU; stepping motor controller, actuator controller, follow-up delay detection means and steady state determination means 2a; accelerator opening sensor; intake air amount increase/decrease instruction means S22
and S27; intake air amount increase/decrease instruction means S3 and S21; follow-up delay detection step S4; steady state determination step

Claims (2)

[Claims] 1. A main intake passage that guides intake air to the internal combustion engine, a throttle valve that opens and closes the main intake passage, a stepping motor that opens and closes the throttle valve, and a bypass that guides a portion of the intake air by bypassing the throttle valve. an intake passage, a bypass flow rate adjustment valve that opens and closes the bypass intake passage, an actuator that opens and closes the bypass flow rate adjustment valve, an intake air amount increase/decrease instruction means that instructs an increase or decrease in the amount of intake air required by the internal combustion engine, and a tracking motor for the stepping motor. A follow-up delay detection means for detecting the occurrence of a delay, a stepping motor controller that increases or decreases the number of steps of the stepping motor in response to instructions from the intake air amount increase/decrease instruction means, and when no follow-up delay is detected by the follow-up delay detection means. In accordance with a request amount corresponding control mode that controls the operation of the actuator in response to the instruction from the intake air amount increase/decrease instruction means, when a follow-up delay is detected by the follow-up delay detection means, the instruction from the intake air amount increase/decrease instruction means is performed. An actuator controller that controls the operation of the actuator in accordance with a control mode that operates as described above to compensate for the influence of the follow-up delay. 2. According to claim 1, further comprising means for determining whether or not the internal combustion engine is operating in a substantially steady state, and control for fixing the actuator when the internal combustion engine is operating in a steady state. An intake air amount adjusting device for an internal combustion engine, characterized in that an aspect is added to the actuator controller.