JPH0715274B2 - Throttle valve control device for internal combustion engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a throttle valve control device that feedback-controls a throttle valve opening of an internal combustion engine to a target opening.

2. Description of the Related Art In recent years, various traction control systems have been proposed in which, when a drive wheel of a vehicle slips, the output of the internal combustion engine is immediately reduced to suppress the slip ratio within a certain range. In such a traction control system, it is necessary to electronically control the throttle valve opening for output adjustment. In this case, a so-called single throttle type and a tandem throttle type are known.

The former is designed to electronically control only one throttle valve provided in the intake passage, and the target opening is determined based on the accelerator pedal depression amount by the driver, a slip detection signal, and the like. The actual opening is controlled along with. That is, normally, the throttle valve opening is controlled in a form that uniquely corresponds to the accelerator pedal depression amount by the driver,
Moreover, when slip is detected, the target opening is corrected so as to become smaller.

The latter has a structure in which a main throttle valve and a sub-throttle valve are arranged in series in an intake passage, and the main throttle valve is linked to an accelerator pedal via an accelerator wire, for example. The sub-throttle valve is normally urged by a return spring so that it is fully opened, and the opening of the sub-throttle valve is electronically controlled based on slip detection. That is, the sub-throttle valve closes only when slip is detected, and the engine intake air amount is suppressed.

Here, in order to electronically control the throttle valve opening as described above, the throttle valve is driven by an actuator such as a servomotor or a pulse motor as described in, for example, Japanese Patent Application Laid-Open No. 61-192824. On the other hand, a method is generally used in which the actual throttle valve opening is detected by a throttle valve opening sensor directly connected to the throttle shaft, and the actuator is feedback-controlled based on the deviation between the actual opening and the target opening. Is.

By the way, when controlling the throttle valve opening based on the output signal of the throttle valve opening sensor in this way, its output characteristics deviate from the design reference characteristics due to manufacturing errors and mounting errors of the throttle valve opening sensor. If so, accurate opening control cannot be achieved.

For example, the throttle valve opening sensor may output a fully closed signal even if the actual throttle valve opening is not fully closed.In such a case, control is required to fully close the throttle valve. Even if it is executed, it cannot actually obtain a completely closed state.

Moreover, despite the fact that the throttle valve is actually fully closed. An opening signal indicating that the throttle valve is still open may be output, and in this case, there is a possibility that the actuator may continue to be driven in order to further close the throttle valve.

Therefore, the output values of the throttle valve opening sensor corresponding to the actual fully closed position and fully open position of the throttle valve positioned by a mechanical stopper etc. are stored as the fully closed learning value and the fully open learning value during actual operation, respectively. However, some control devices have been proposed that correct the output characteristic of the throttle valve opening sensor, that is, the correlation between the output value of the throttle valve opening sensor and the throttle valve opening, based on the learned value. There is.

Problems to be Solved by the Invention When the output values at the fully closed position and the fully opened position are read as learning values as described above, either one of them is read after the throttle valve is forcibly operated. For example, taking the above-mentioned sub-throttle valve of the tandem throttle type as an example, since the sub-throttle valve is always urged in the fully open direction by the return spring, the learning value at the fully open position can be read at any time. In order to learn the fully closed position, it is necessary to forcibly operate the sub-throttle valve to the fully closed position that is mechanically restricted and read the output value of the opening sensor as a learned value in that state. .

Therefore, the learning of the fully open position and the fully closed position, especially the learning of the fully closed position is generally performed only once, for example, when the engine is started, immediately after the ignition key is turned on, and when a predetermined learning condition is satisfied. Target.

However, if the learning values for full open and full close are updated only at the time of starting a specific engine as described above, for example, after the user of the automobile re-adjusts the mounting position of the throttle valve opening sensor, it is forcibly forced. If the vehicle continues to travel without learning the fully closed position, or if the throttle valve opening sensor mounting position is slightly misaligned during travel, wait until the next learning. However, there is a problem that the operation is continued with the control accuracy lowered.

Means for Solving the Problems A throttle valve control device for an internal combustion engine according to the present invention is installed in an intake passage 1 of the internal combustion engine, as shown in FIG.
Further, a throttle valve 3 biased by a return spring 2 toward a fully open position or a fully closed position, an actuator 4 for driving the throttle valve 3 to open and close, and a throttle valve opening sensor for detecting the opening of the throttle valve 3. 5, a first learning value storage means 6 for storing the output value of the throttle valve opening sensor 5 at the fully open position or the fully closed position held by the return spring 2 as a first learning value, and the return spring 2 Second learning value storage means 7 for storing the output value of the throttle valve opening sensor 5 at the fully closed position or the fully open position on the side opposite to the urging direction as the second learning value, and the first learning value during engine operation. First learning value updating means 8 for updating based on a variation in the output value of the throttle valve opening sensor 5, and the updated first learning value.
The second learning value updating unit 9 corrects and updates the second learning value according to the difference between the learning value and the previous value.

Action When the throttle valve 3 is biased in the fully opening direction by the return spring 2 like a sub-throttle valve in a tandem throttle type throttle mechanism,
The output value corresponding to the fully open position is read as the first learning value, and the output value corresponding to the fully closed position is read as the second learning value. Then, when the output value corresponding to the fully open position fluctuates from the first learning value up to that point during engine operation, the first learning value is updated using that value. At the same time, the second learning value is also corrected and updated according to the difference between the updated first learning value and the previous value.

When the mounting position of the throttle valve opening sensor 5 moves to one side, the output value corresponding to the fully open position and the output value corresponding to the fully closed position change substantially equally.

When the throttle valve 3 is biased in the fully closed direction by the return spring 2 as in the single throttle type, the output value corresponding to the fully closed position is the first learning value,
The output value corresponding to the fully open position becomes the second learning value.

Embodiment An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 2 shows an embodiment in which the present invention is applied to a vehicle traction control system of a tandem throttle type.

In the figure, 11 is an internal combustion engine equipped with a fuel injection valve 12 as a fuel supply system, and an intake passage 13 through which intake air flows.
In addition, a butterfly valve type main throttle valve 14 and a butterfly valve type sub-throttle valve 15 are arranged in series. The main throttle valve 14 is mechanically linked to an accelerator pedal 16 via an accelerator wire 17, and is biased in a fully closed direction by a return spring (not shown). Also, this main throttle valve
A first throttle valve opening sensor 18, which is a potentiometer, is coaxially attached to the end of the throttle shaft 19 to detect the opening θ ₁ of the valve 14.

The sub-throttle valve 15 is electronically controlled irrespective of the driver's intention.A servo motor 21 is directly connected to one end of the throttle shaft 20 as an actuator for driving the sub-throttle valve 15 to open and close. A second throttle valve opening sensor 22, which is a potentiometer, is coaxially attached to the other end of the throttle shaft 20 to detect the opening θ ₂ . The sub-throttle valve 15 is fully urged by a return spring (not shown).

Reference numeral 23 is a motor control unit that feedback-controls the servo motor 21, and the actual opening θ ₂ of the sub-throttle valve 15 detected by the second throttle valve opening sensor 22 and TCS (traction control system)
The servo motor 21 is driven so that the deviation becomes zero by comparing with the target opening degree θ output from the control unit 25. In addition, 26 is a relay for fail safe,
When the power is cut off by the relay 26 or the fuse 27, the sub-throttle valve 15 is kept fully open by the return spring.

Reference numeral 28 is an engine control unit that mainly controls the fuel supply amount from the fuel injection valve 12, the ignition timing by an ignition plug (not shown), and the like. The engine control unit 28 includes an intake air amount signal Qa detected by an air flow meter 29, a crank angle signal Ca by a crank angle sensor 30,
Each detection signal such as the vehicle speed signal VSP by the vehicle speed sensor 31 and the engine cooling water temperature signal TW by the water temperature sensor 32 is input, and the above air-fuel ratio control and the like are performed based on these detection signals. The engine speed N is obtained from the crank angle signal Ca. Again 33
Is a neutral switch for detecting that the transmission is in the parking position or the neutral position, and the detection signal thereof is also input to the engine control unit 28.

34 is an AT control unit for switching control of the shift solenoids 35, 36 of the automatic transmission based on the opening θ ₁ of the main throttle valve 14 and the vehicle speed VSP input via the engine control unit 28, The switching signal is also input to the TCS control unit 25 at the same time.

The TCS control unit 25 detects the slip of the drive wheel based on the detection signals of the wheel speed sensors 37, 38, 39, 40 provided on the front, rear, left and right wheels, and when the slip occurs, the sub-throttle valve 15 Traction control is executed to reduce the output torque of the engine by changing the target opening θ and suppress slip. At the same time, the brake oil pressure of each wheel is individually controlled via the brake oil pressure actuator 41 to execute brake control for suppressing slip. In addition, 42 is a brake switch that detects the depression operation of the brake pedal 43, 44 is a traction ON / OFF switch that selects whether or not to operate the traction control system, and 45 is a warning light that lights when an abnormality occurs in the traction control system. .

Further, 46 is an ignition key switch provided in the driver's seat or the like, and when this is turned to the ON position, the TCS is turned on.
When the main power source is turned on to the entire system such as the control unit 25 and further rotated to the start position, a starter motor (not shown) operates to start cranking the internal combustion engine.

Now, in the above configuration, the basic output adjustment of the internal combustion engine 11 is performed by the main throttle valve 14 mechanically linked to the accelerator pedal 16. Sub throttle valve 15
Is feedback-controlled so as to follow the target opening degree θ sequentially output from the TCS control unit 25, but is maintained in the fully open state unless slip of the drive wheels is detected. When the slip is detected, the target opening θ is controlled in the closing direction, so that the engine output is quickly suppressed. Therefore, even when the driver suddenly depresses the accelerator pedal 16 on a low μ road, the slip of the drive wheels is always controlled within a certain range.

By the way, the opening θ ₂ of the sub-throttle valve 15 is set to the second
A value obtained by A / D converting the output voltage of the throttle valve opening sensor 22 T
Since it is detected based on VO, there is a correlation between the output value TVO and the opening θ ₂ as shown by the solid line in FIG. 3, but in reality, this characteristic is the second throttle. The valve opening sensor 22 varies due to manufacturing errors, mounting errors, etc., and the detection of the opening of the sub-throttle valve 15 becomes inaccurate.

Therefore, the output values corresponding to the actual fully open position and the fully closed position of the sub-throttle valve 15 are read as the fully open learning value and the fully closed learning value, respectively, and the output characteristics are corrected.

FIG. 4 shows the outline of the control program executed in the TCS control unit 25. When the ignition key switch 46 is turned to the ON position and the main power is turned on, the full-open learning is performed immediately thereafter. (Step 1) is executed. That is, at this time, since the sub-throttle valve 15 is held at the fully open position by the return spring, the output value TVO of the second throttle valve opening sensor 22 at that time is read, and this is the fully open learning value TVO.
It is stored in memory as OP.

Then, fully closed learning (step 2) is executed. In this fully closed learning, first, the sub throttle valve 15 is moved until the detected opening θ ₂ is fully closed, and the servo motor 21 is further driven in the closing direction by a predetermined amount to surely bring the sub throttle valve 15 to the fully closed position. Then, the output value TVO of the second throttle valve opening sensor 22 at that time is read, and this is the fully closed learning value TVOCL.
Is stored in memory as. When the reading of the output value TVO is completed, the sub throttle valve 15 is immediately returned to the open state. If the engine cooling water temperature TW or the like is not under the predetermined learning condition, the above learning is not performed.

With the above, the initial setting of the learning value is completed, and thereafter, the throttle control for normal traction control (step 3) is repeatedly executed until the operation ends. At the same time, the update process (step 4) is repeatedly executed to constantly monitor whether or not the position adjustment of the second throttle valve opening sensor 22 has been performed by the user or the like and perform necessary update.

The flowchart of FIG. 5 shows the specific contents of this updating process. First, it is judged from the control state at that time whether or not the sub-throttle valve 15 is at the fully open position. If it is not fully open, the learning value is not updated. If it is in the fully open position, the second throttle valve opening sensor 22 at that time
The output value TVO of is read (step 12), and this is compared with the full open learning value TVOOP so far (step 13).

Normally, the output value TVO corresponding to the fully open position does not change abruptly, so they are equal. In this case, of course, the learning value is not updated.

On the other hand, when the position adjustment of the second throttle valve opening sensor 22 or the like is performed, the two do not match. In this case, the difference between the two, that is, the detected output value TVO and the previous fully open learning value. The fully closed learning value TVOCL is corrected by the difference from TVOOP, and this is updated as a new totally closed learning value TVOCL (step 14). At the same time, the detected output value TVO is updated as the fully open learning value TVOOP (step 15).

That is, when the mounting position of the second throttle valve opening sensor 22 mounted coaxially on the sub-throttle valve 15 swings around the throttle shaft 20, its output characteristic is as shown by the imaginary line in FIG. , While keeping a predetermined inclination, it shifts up and down as a whole. Therefore, as described above, if the fully closed learning value TVOCL is corrected by the variation amount ΔTVO at the fully open position, the output characteristic is obtained sufficiently accurately without directly detecting the output value TVO at the fully closed position. It is possible.

Therefore, during the next operation, the opening control can be performed with extremely high accuracy until the fully closed learning value TVOCL is updated based on the actual output value TVO at the fully closed position.

In the above embodiment, the fully closed learning value TVOCL is basically newly updated every time the operation is started, but as described above, the fully closed learning value TVOCL is linked with the update of the fully open learning value TVOOP.
If you want to update CL, set the update frequency to
For example, it is possible to reduce the number remarkably every periodic inspection.

Although the embodiment of the tandem throttle type has been described in detail above, the present invention can be similarly applied to the single throttle type in which the return spring normally biases the throttle in the closing direction. In this case, as described above, when the fully closed learning value TVOCL changes, the fully opened learning value TVOOP may be corrected by the change amount ΔTVO.

Further, the present invention is not necessarily limited to the one provided with the traction control system, and regardless of this, it can be widely applied to the throttle valve control device for performing the correction by learning the full opening and the full closing. is there.

EFFECTS OF THE INVENTION As is clear from the above description, in the throttle valve control device for an internal combustion engine according to the present invention, the throttle valve control device does not forcibly move the throttle valve, and the full-open position and the full-open position are maintained at the normal position maintained by the return spring. Both closed positions can be learned while driving. Therefore, for example, after the user re-adjusts the mounting position of the throttle valve opening sensor,
Even if the vehicle is driven without learning the forced fully closed or fully open position, or if the throttle valve opening sensor mounting position deviates to one side during traveling, the throttle valve opening Detection accuracy can be sufficiently ensured. Therefore, it is possible to surely prevent a situation in which the durability of the actuator is deteriorated by trying to move the actuator from the actual fully closed position in the closing direction.

In addition, it is possible to reduce the frequency of learning, for example, at regular inspections, instead of performing learning for those who need to forcibly move the throttle valve in the fully open position and the fully closed position every time the engine is started. Become.

[Brief description of drawings]

FIG. 1 is a diagram showing the structure of a throttle valve control device according to the present invention, and FIG. 2 is a structural explanatory view showing an embodiment of the present invention. FIG. 3 is an example of output characteristics of a throttle valve opening sensor. FIG. 4 is a flow chart showing the outline of the control of the above embodiment, and FIG. 5 is a flow chart of the updating process. 3 ... Throttle valve, 4 ... Actuator, 5 ... Throttle valve opening sensor, 6 ... First learning value storage means, 7 ... Second learning value storage means, 8 ... First learning value updating means, 9 ... Second learning value Update means.

Claims (1)

[Claims] 1. A throttle valve interposed in an intake passage of an internal combustion engine and urged toward a fully open position or a fully closed position by a return spring, an actuator for opening and closing the throttle valve, and the throttle valve. A throttle valve opening sensor for detecting the opening; first learning value storage means for storing an output value of the throttle valve opening sensor at the fully open position or the fully closed position held by the return spring as a first learning value; The output value of the throttle valve opening sensor at the fully closed position or the fully open position opposite to the urging direction of the return spring is set to the second value.
Second learning value storage means for storing as a learning value, first learning value updating means for updating the first learning value based on the variation of the output value of the throttle valve opening sensor during engine operation, and the updated learning value updating means. According to the difference between the first learning value and the previous value, the second
A throttle valve control device for an internal combustion engine, comprising: a second learned value updating means for correcting and updating a learned value.