JP3006233B2 - Throttle valve drive for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for driving a throttle valve provided in an intake passage of an internal combustion engine.
More particularly, the present invention relates to a throttle valve driving device for an internal combustion engine in which the rotation speed of a step motor connected to a throttle valve is adjusted to control the opening / closing operation of the throttle valve.

[0002]

2. Description of the Related Art Conventionally, for example, a traction control system (e.g., on a slippery road surface such as a snowy road and a frozen road)
In a vehicle equipped with a system for preventing the drive wheels from slipping at the time of starting or accelerating, the opening of the throttle valve (or the auxiliary throttle valve) of the internal combustion engine is adjusted independently of the operation of the accelerator pedal. Like that. And
There is a technique using a step motor as an actuator for driving the throttle valve (or the auxiliary throttle valve). In this technique, the step motor is driven to rotate by sequentially switching the energization to the excitation coil of the step motor.

That is, as shown in the prior art in FIG. 11, when the target step position of the step motor calculated according to the operation state of the internal combustion engine is TS11, the actual step position MS of the step motor at that time is detected. The switching to the exciting coil is controlled so that the deviation between the two step positions TS11 and MS becomes zero. More specifically, when the deviation is larger than a predetermined value (period from timing t50 to t51), the switching time of the exciting coil is gradually shortened to accelerate the rotation of the step motor, and the deviation is reduced. When the value is equal to or less than the predetermined value (period between timings t51 and t52), the switching time of the exciting coil is gradually increased to reduce the rotation of the step motor. That is, the actual step position MS
Is made to coincide with the target step position TS11, the rotation of the step motor is accelerated while the difference between the two step positions MS and TS11 is large, and when the difference becomes smaller, the state is shifted from the acceleration state to the deceleration state.

In the above-described step motor, damping vibration is generated every time the energization of the excitation coil is switched, so that the step motor may lose synchronism depending on the timing of the next energization switching. Therefore, for example, Japanese Patent Application Laid-Open
In the "throttle valve driving method" disclosed in Japanese Patent Application Laid-Open No. 173328, the switching timing of the energization to the exciting coil is set to a point in time when the vibration generated by the previous switching is attenuated to some extent. I try to prevent it.

[0005]

However, in the above two prior arts, the target step position is changed from TS11 to TS12 due to a change in the operating state of the internal combustion engine while the acceleration and deceleration of the step motor are being performed in order. When it is necessary to change the speed and need to be re-accelerated, acceleration, deceleration, and acceleration are performed. Then, the acceleration / deceleration frequency f coincides with the resonance frequency fc inherent in the stepping motor, and there is a possibility that step-out may occur. Here, the acceleration / deceleration frequency f is, for example, at the start of the first acceleration (timing t50).
And the reciprocal (1 / T2) of the time (cycle T2) required from the start of reacceleration (timing t52).

As a countermeasure against this, as shown by the improved technique in FIG. 11, the deceleration after the first acceleration is performed until the rotation of the step motor is temporarily stopped, and the stopped state is maintained for a certain time (timing t53). It is conceivable that the vehicle is re-accelerated. That is, by stopping the rotation of the step motor for a certain period of time, from the start of the initial acceleration (timing t50) to the start of the re-acceleration (timing t50).
The cycle T3 up to 53) is made larger than the cycle T2,
That is, the driving frequency f is changed to the resonance frequency f of the step motor.
Step out is prevented by setting it smaller than c.

[0007] However, although this step can certainly prevent step-out, the time required to reach the target step position TS12 becomes longer due to the stoppage of the stepping motor for a certain period of time. Responsiveness of the opening / closing operation is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to prevent loss of synchronism in a step motor for driving a throttle valve and to improve responsiveness when the throttle valve is driven. It is an object of the present invention to provide a possible throttle valve drive for an internal combustion engine.

[0009]

As shown in FIG. 1, the present invention provides a throttle valve M3 provided in an intake passage M2 of an internal combustion engine M1 so as to be openable and closable, and a throttle valve M3. And the throttle valve M3
, A motor driving means M5 for rotatingly driving the step motor M4 by sequentially switching energization to an exciting coil of the step motor M4, and an operation state detection for detecting an operation state of the internal combustion engine M1. Means M6 and the stepping motor M according to the operating state of the internal combustion engine M1 by the operating state detecting means M6.
4, a target step position calculating means M7 for calculating a target step position, an actual step position detecting means M8 for detecting an actual step position of the step motor M4, an actual step position by the actual step position detecting means M8, A deviation calculating means M9 for calculating a deviation from the target step position by a step position calculating means M7, and a deviation calculated by the deviation calculating means M9 from a predetermined value so as to make the actual step position coincide with the target step position. Is larger, the switching time of the exciting coil by the motor driving means M5 is gradually shortened, and the stepping motor M4
An acceleration unit M10 for accelerating the rotation of the motor, and switching of the excitation coil by the motor driving unit M5 when the deviation by the deviation calculating unit M9 is equal to or less than the predetermined value so that the actual step position coincides with the target step position. Decelerating means M11 for gradually increasing the time to reduce the rotation of the step motor M4; and accelerating means M10 in accordance with the deviation between the actual step position and the target step position.
When the acceleration of the step motor M4 and the deceleration by the deceleration means M11 are sequentially performed, the target step position changes due to a change in the operation state of the internal combustion engine M1, and the reacceleration by the acceleration means M10 becomes necessary. In this case, before the re-acceleration is executed, the predetermined time set so that the frequency when the period from the first acceleration to the re-acceleration is one cycle is set to be smaller than the resonance frequency of the step motor M4, A constant speed means M12 for driving the step motor M4 at a constant speed at the drive speed at the time when the deceleration by the speed reducing means M11 is completed.

[0010]

During operation of the internal combustion engine M1, the operating state detecting means M6 detects the operating state, and the actual step position detecting means M8 detects the actual step position of the step motor M4. Further, the target step position calculating means M7
A target step position of the step motor M4 according to the operation state of the internal combustion engine M1 by the operation state detection means M6 is calculated. Further, the deviation calculating means M9 calculates a deviation between the actual step position by the actual step position detecting means M8 and the target step position by the target step position calculating means M7. Then, a step motor is driven to make the actual step position coincide with the target step position. At this time, the rotation speed of the step motor is adjusted according to the magnitude of the deviation.

That is, when the deviation calculated by the deviation calculating means M9 is larger than a predetermined value, the acceleration means M10 gradually shortens the switching time of the exciting coil by the motor driving means M5 to reduce the rotation speed of the step motor M4. Accelerate. When the deviation is equal to or smaller than the predetermined value, the speed reduction means M11 gradually increases the switching time of the excitation coil, and reduces the rotation speed of the step motor M4.

As described above, when the acceleration and deceleration of the step motor M4 are sequentially performed in accordance with the deviation, the target step position changes due to a change in the operation state of the internal combustion engine M1, and the acceleration means M10 continues. When the re-acceleration is required, the constant speed means M12 drives the stepping motor M4 at a constant speed for a predetermined time before the re-acceleration is executed at the drive speed at the time when the deceleration by the deceleration means M11 is completed.

Accordingly, the step motor M4 is driven to rotate during the period from the end of the deceleration to the re-acceleration, whereby the throttle valve M3 also rotates in the valve opening direction or the valve closing direction. Therefore, the time required for the actual step position of the step motor M4 to coincide with the target step position is shorter than in the case where the stop state continues for a certain period of time from the end of the deceleration to the re-acceleration.

In the present invention, the predetermined time from the end of the deceleration to the execution of the re-acceleration is set so that the frequency when the period from the first acceleration to the re-acceleration is one cycle is smaller than the resonance frequency of the step motor M4. Is set. Therefore, it is possible to prevent the frequency at the time of driving the step motor M4 from being equal to the unique resonance frequency of the step motor M4.

[0015]

FIG. 2 shows an embodiment of the present invention.
This will be described with reference to FIG. As shown in FIG. 2, a cylinder 2 of an engine 1 as an internal combustion engine accommodates a piston 3 that moves up and down with rotation of a crankshaft (not shown). A combustion chamber 4 is formed above the piston 3, and an intake passage 5 and an exhaust passage 6 communicate with the combustion chamber 4. The communication portion between the combustion chamber 4 and the intake passage 5 is an intake port 7, which is opened and closed by an intake valve 9 movably mounted on a cylinder head 8. The communicating portion between the combustion chamber 4 and the exhaust passage 6 is an exhaust port 11.
1 is opened and closed by an exhaust valve 12 attached to the cylinder head 8 so as to be vertically movable.

In the intake passage 5, a fuel injection valve 13 is mounted near the intake port 7. Further, a throttle valve 14 is provided in the intake passage 5 upstream of the fuel injection valve 13. This throttle valve 14
Is driven by a step motor 15 to open and close the intake passage 5 and regulate the amount of intake air to the combustion chamber 4. As shown in FIG. 3, the step motor 15 includes a rotor 16 and a plurality of excitation coils A and B, a bar A, and a bar B arranged at equal angles (90 degrees in the present embodiment) on the outer periphery thereof. The rotor 16 is rotated by sequentially switching the energization to these excitation coils A and B, bar A and bar B. For example, when energization is performed in the order of the excitation coils A, B, bar A, and bar B, the rotor 16 rotates counterclockwise in FIG. 3, and conversely, the excitation coils A, bar B, bar A, When energization is performed in the order of B, the rotor 16 rotates clockwise in FIG.

As shown in FIG. 2, a mixture of fuel injected from the fuel injection valve 13 and outside air introduced into the intake passage 5 passes through the intake port 7 when the intake valve 9 is opened. It is introduced into the combustion chamber 4. This combustion chamber 4
A spark plug (not shown) is attached to the cylinder head 8 to ignite the mixture introduced into the cylinder head 8.
This spark plug is driven based on an ignition signal distributed by the distributor 17. The distributor 17 distributes the high voltage output from the igniter 18 to the ignition plug in synchronization with the crank angle of the engine 1. Then, the air-fuel mixture introduced into the combustion chamber 4 is exploded and burned by the ignition of the spark plug, and the driving force of the engine 1 is obtained through the piston 3, the crankshaft and the like. When the exhaust valve 12 is opened, the burned gas burned in the combustion chamber 4 is exhausted by the exhaust port 11.
Is discharged to the outside through the exhaust passage 6.

The engine 1 and the like are provided with the following various sensors. That is, in the vicinity of the throttle valve 14, a throttle position sensor 23 as an actual step position detecting means for detecting a throttle opening is provided, and a distributor 17 is provided with a rotational speed for detecting an engine rotational speed from the rotational speed of the rotor. A sensor 24 is provided. The throttle position sensor 23
Even if there is no, by the program in the CPU 33 described later,
The actual step position can also be known by changing and storing the current position each time a drive instruction is output to the step motor 15, so that the function can be used as an actual step position detecting means. . Further, a water temperature sensor 25 for detecting a cooling water temperature is provided in a cooling system of the cylinder block 19 of the engine 1, and an air flow meter 26 for detecting an intake air amount is provided downstream of the air cleaner 21. Further, the accelerator pedal 22 is provided with an accelerator sensor 27 as operating state detecting means for detecting an operation amount (accelerator opening θa), and a transmission (not shown) is provided with a vehicle speed sensor 28 for detecting a vehicle speed. Have been. The shift lever (not shown) is provided with a neutral switch 29, which detects whether the shift range indicating the position of the shift lever is a neutral range (N range) or another drive range (D range). .

The various sensors 23 to 28 and the neutral switch 29 are electrically connected to the input side of an electronic control unit (hereinafter referred to as "ECU") 31. A drive circuit 32 serving as a motor drive unit for rotating the step motor 15 by sequentially switching energization to the excitation coils A, B, bar A, and bar B of the step motor 15 is electrically connected to the output side of the ECU 31. It is connected to the.

The ECU 31 includes a central processing unit (hereinafter referred to as CPU) 33 as target step position calculating means, deviation calculating means, accelerating means, decelerating means and constant speed means, a read-only memory (hereinafter referred to as ROM) 34, An access memory (hereinafter referred to as RAM) 35, an input port 36, and an output port 37 are provided, and these are connected to each other by a bus 38. The CPU 33 executes various arithmetic processes according to a preset control program, and the ROM 34 stores in advance a control program and initial data necessary for the CPU 33 to execute the arithmetic processes. The RAM 35 temporarily stores the calculation result of the CPU 33.

Detection signals from the various sensors 23 to 28 and the neutral switch 29 are input to an input port 36. The CPU 33 outputs a drive signal for driving the step motor 15 to the drive circuit 32 via the output port 37 based on these signals.

The CPU 33 calculates a target step position (the number of steps) TS of the step motor 15 corresponding to the target opening in order to set the opening of the throttle valve 14 to a target opening corresponding to the operating state at that time. I do. CPU3
3 calculates the actual step position MS of the step motor 15 corresponding to the valve opening from the throttle position sensor 23. Then, the CPU 33 sets the target step position TS
And the actual step position MS, the stepping motor 15 according to the deviation (TS-MS) between the two step positions.
Of the excitation coils A, B, A, B are controlled.

The rotation speed of the stepping motor 15 is accelerated or decelerated by changing the energizing time to the exciting coils A and B, the bar A and the bar B. That is, the rotation speed is increased (accelerated) by gradually shortening (for each step) the drive time required for the step motor 15 to rotate one step. Conversely, the step motor 15
The rotation speed is reduced (decelerated) by gradually (every step) increasing the drive time required for rotating by one step.

In order to express the acceleration / deceleration, in the present embodiment, the rotation speed SPDL of the step motor 15 is expressed as follows. The rotational speed SPDL in the direction in which the throttle valve 14 is opened is represented by a positive number such as SPDL = 1, 2, 3, 4,.... Here, it is assumed that SPDL = 1 is the slowest and the larger the number, the faster the speed. Also,
Rotation speed SPD in the direction to close throttle valve 14
L is represented by a negative number such as SPDL = -1, -2, -3, -4. Here, it is assumed that SPDL = -1 is the slowest, and the smaller the number, the faster the speed. That is, regardless of the opening and closing direction of the throttle valve 14, when the absolute value | SPDL |
Conversely, when the absolute value | SPDL | decreases, the vehicle decelerates.

Then, according to the following rules, the rotational speed SPD
By changing L for each step, the actual step position MS is made to coincide with the target step position TS. Note that SPDL = 0 indicates a stationary state. TS-MS ≧ 0 (when opening the throttle valve 14) (a) When TS-MS ≧ SPDL + 1: “1” is added to SPDL to obtain a new SPDL. (B) When TS-MS = SPDL: SPDL is used as it is. (C) When TS-MS <SPDL: “1” is subtracted from SPDL to obtain a new SPDL. TS-MS <0 (when closing the throttle valve 14) (c) When TS-MS ≦ SPDL-1: “1” is subtracted from SPDL to obtain a new SPDL. (D) When TS-MS = SPDL, SPDL is used as it is. (E) When TS-MS> SPDL, “1” is set in SPDL
Are added to obtain a new SPDL.

A case where the throttle valve 14 is opened according to the above rules will be described with reference to FIG. This figure 5
At this time, both the target step position TS of the step motor 15 and the actual step position MS coincide with “0”, the rotation of the step motor 15 stops, and the rotation speed S
It is assumed that PDL = 0.

At time t0, when the target step position TS changes from "0" to "7", then TS-MS = 7-0 = 7, which is SPDL
SPDL is (a) because it is larger than + 1 = 0 + 1 = 1.
SPDL = 0 + 1 = 1.

At timing t1, TS-MS =
7-1 = 6, and this value is SPDL + 1 = 1 + 1 = 2
SPDL is larger than SPDL of (a) = 1 +
1 = 2.

At timing t2, TS-MS =
7-2 = 5, and this value is SPDL + 1 = 2 + 1 = 3
SPDL is larger than SPDL of (a) = 2 +
1 = 3.

At timing t3, TS-MS =
7-3 = 4, and this value is SPDL + 1 = 3 + 1 = 4
Since SPDL is the same as SPDL, SPDL in (a) = 3 +
1 = 4.

At timing t4, TS-MS =
7-4 = 3, which is smaller than SPDL = 4, the SPDL is (c) SPDL = 4-1 = 3. At timing t5, TS-MS = 7−5 =
2, which is smaller than SPDL = 3,
The PDL is SPDL of (c) = 3-1 = 2.

At timing t6, TS-MS =
7-6 = 1, and since this value is smaller than SPDL = 2, the SPDL becomes SPDL = 2-1 = 1 in (c). At timing t7, TS-MS = 7−7 =
0, which is smaller than SPDL = 1,
In the PDL, SPDL of (c) = 1-1 = 0, and the rotation of the step motor 15 stops.

Here, as described above, the rotational speed SPD
When the absolute value | SPDL | of L increases, the vehicle accelerates, and conversely, when the absolute value | SPDL | decreases, the vehicle decelerates. Therefore, during the period from timing t0 to t3, the vehicle accelerates and decelerates during the period from timing t4 to t7. Will be.

The operation of closing the throttle valve 14 is the same as that described above when the valve is opened, and a description thereof will be omitted. Next, the operation of the present embodiment configured as described above will be described with reference to FIGS.

The flowcharts of FIGS.
3 among the processes executed by step motor 1
5 is a drive control routine for driving the control unit 5 and is started by a periodic interruption every predetermined time. In this routine, a flag STATUS is prepared. This flag STAT
US indicates that the rotation of the step motor 15 changes from an acceleration state to a deceleration state, and the target step position T
Even if S changes and becomes capable of acceleration, it does not accelerate, but maintains the final rotational speed in the decelerating state before the acceleration (constant speed state). Then, the flag ST
ATUS is set to "1" at the time of deceleration and for a fixed time (while this processing routine is repeated a predetermined number of times)
Set to "2" when maintaining the constant speed state, when acceleration is possible (when there is no restriction on constant speed after deceleration and acceleration is free)
Is set to “3”. In the initial state, the flag STATUS is set to "3".

FIGS. 9 and 10 are diagrams showing the relationship between the time and the step position of the step motor 15. FIG. Here, before shifting to this processing routine, the stepping motor 1 corresponding to the accelerator opening θa by the accelerator sensor 27 is used.
5, the actual step position MS corresponding to the actual opening of the throttle valve 14 by the throttle position sensor 23 coincides with “100”, the step motor 15 stops, and the rotation speed SPDL becomes “100”. 0 ".

FIG. 9 shows a case where the step motor 15 is driven to rotate to the opening side of the throttle valve 14. Here, when the accelerator pedal 22 is depressed at the timing t0, the target step position TS becomes “10”.
0 ”to“ 107 (TS1) ”at timing t
The acceleration and deceleration of the step motor 15 are performed during the period from 0 to t4, and the accelerator pedal 22 is further depressed at the timing t4 'during this deceleration, so that the target step position TS changes from "107" to "117 (TS2)". It has changed.

FIG. 10 shows a case where the step motor 15 is driven to rotate to the closing side of the throttle valve 14. Here, at timing t0a, the accelerator pedal 2
2 is slightly opened, the target step position TS changes from "100" to "93 (TS3)", and the step motor 15 is accelerated and decelerated during the period from timing t0a to t4a, and the timing during this deceleration It is assumed that the target step position TS has changed from "93" to "83 (TS4)" by further releasing the accelerator pedal 22 at t4'a.

First, a description will be given of a case where the driver depresses the accelerator pedal 22 from the previous position at timing t0 in FIG. 9 to accelerate the vehicle. The CPU 33 reads the accelerator opening θa from the accelerator sensor 27 in step 101 of FIG. 6, and calculates a target step position TS corresponding to the accelerator opening θa from the map of FIG. This map contains the accelerator opening θa
Is set in advance.
Then, the CPU 33 calculates the target step position TS1 (= 107) according to the accelerator opening θa1 at that time as the target step position TS from FIG.

When determining the target step position TS1, the CPU 33 determines whether or not the deviation between the target step position TS1 and the actual step position MS is 0 or more in step 102 of FIG. At the timing t0, the deviation TS1-MS of both step positions is 107-100 = 7 (≧
0). For this reason, the CPU 33 controls the throttle valve 14
It is determined that it is necessary to rotate the step motor 15 in the valve opening direction, and in step 103, the difference between the two step positions is a value obtained by adding a predetermined value (in this case, “1”) to the rotation speed SPDL of the step motor 15. It is determined whether it is greater than or equal to. At timing t0, the rotation speed SPDL
= 0, and the value obtained by adding “1” to the rotation speed SPDL is 0 + 1 = 1. Since the deviation (= 7) is larger than this value, the CPU 33
It is determined that it is possible to increase (accelerate) the rotation speed of No. 5 and it is determined in step 104 whether the flag STATUS is “3”. This flag STATU
Since S is initially set to “3”, the CPU 33 proceeds to step 105 and executes the stepping motor 15 at that time.
The value obtained by adding “1” to the rotation speed SPDL (= 0) of
A new rotation speed SPDL is set. That is, the rotation speed SP
Update DL to “1”.

Next, the CPU 33 proceeds to step 106 in FIG.
Then, the rotational speed SPDL at that time is compared with “0”. At timing t0, the rotational speed SPDL is 1 (> 0) in step 105, so that the CPU 3
3 is the actual step position MS at that time in step 107
(= 100) and “1”, and the addition result (100
+ 1 = 101) is set as a new actual step position MS.

Next, the CPU 33 proceeds to step 108 and energizes a predetermined exciting coil of the step motor 15 for a time determined by the rotation speed SPDL (= 1). More specifically, if the remainder obtained by dividing the actual step position MS (= 100) by 4 is “0”, the exciting coil A, if “1”, the exciting coil B, if “2”, the exciting coil bar A,
If "3", the exciting coil bar B is selected. Here, since the remainder is “0”, the excitation coil A is selected. Then, the CPU 33 outputs a drive signal for exciting the selected exciting coil A and deactivating the other exciting coils B, A, and B. As a result, the step motor 15 rotates one step, and the throttle valve 14 opens by an angle corresponding to the one step. After the processing in step 108, the CPU 33 temporarily ends the processing routine.

In the next processing routine started at timing t1 after a predetermined time has passed (for example, after a time determined according to the rotational speed SPDL obtained when the present routine was passed last time), in the determination of step 102, Deviation TS between target step position TS1 and actual step position MS
1−MS = 107−101 = 6 (≧ 0). Also,
In the determination in step 103, the deviation (= 6) between the two step positions is determined by the rotation speed SPDL (=
Since it is larger than the value obtained by adding “1” to 1) (= 2),
The CPU 33 executes steps 101 to 104, and thereafter, in step 105, adds (1) to the rotation speed SPDL (= 1) of the step motor 15 (= 2).
Is a new rotation speed SPDL. Also, the CPU 33
Adds “1” to the actual step position MS (= 101) in step 107, and sets the addition result “102” as a new actual step position MS. Then, the CPU 33 energizes the excitation coil B of the step motor 15 for a time determined by the rotation speed SPDL (= 2) in step 108.

In the processing routine after timing t2, the rotation speed SPDL is increased by "1" at step 105,
In step 107, the actual step position MS increases by "1". Thereby, in the period from timing t0 to t3,
The rotation speed SPDL changes from “0” to “3”, and the time required for the step motor 15 to rotate one step gradually decreases (for each step). Therefore, during this period, the throttle valve 14 rotates in the valve opening direction in an accelerated state.

Then, in step 103 of the processing routine started at timing t4, the target step position TS1
TS1-MS (= 107) between the actual step position MS and the actual step position MS
−104) = 3 is the rotation speed SP of the step motor 15
When the value is smaller than the value (= 5) obtained by adding “1” to DL (= 4), the CPU 33 executes steps 101 to 10
After the processing of step 3, if the rotation of the step motor 15 is continued to be accelerated as it is, the actual step position MS becomes the target step position TS.
In step 109, it is determined whether the deviation is equal to the rotation speed SPDL of the step motor 15. In this determination, since the deviation (= 3) is smaller than the rotation speed SPDL (= 4), the CPU 3
In step 110, a value (= 3) obtained by subtracting a predetermined value (in this case, “1”) from the rotation speed SPDL (= 4) to change from the acceleration state to the deceleration state is used as a new rotation speed SPDL. I do.

Since the CPU 33 has switched from the acceleration state to the deceleration state, the CPU 33 sets the flag STATUS to "1".
Further, the count value CNT by the acceleration prohibition counter is set to a predetermined value n. This acceleration prohibition counter is for prohibiting an acceleration state during this period in order to maintain the rotation speed SPDL for a predetermined period (a period during which this processing routine is repeated a predetermined number of times). The predetermined value n means the number of times (time) that this processing routine is repeated, and is set from the following viewpoint. That is, when acceleration and deceleration of the step motor 15 are sequentially performed, if the target step position TS changes due to a change in the depression amount of the accelerator pedal 22 and re-acceleration is required, the first acceleration is performed. Is set so that the frequency f when the period from to the re-acceleration is set to the cycle T1 is lower than the resonance frequency fc inherent in the step motor 15.

After execution of step 110, the CPU 33 proceeds to step 106, where the rotational speed SPDL (= 3)
> 0, the actual step position MS
(= 104) and “1”, and the addition result “10”
5 "is a new actual step position MS. And CP
U33 energizes the excitation coil of the step motor 15 for a time determined by the rotation speed SPDL (= 3) in step 108. Therefore, at timing t4, the rotation speed SPD
L decreases from “4” to “3”, and the time required for the step motor 15 to rotate one step increases. As a result, the throttle valve 14 rotates in a deceleration state in the valve opening direction.

During the deceleration of the throttle valve 14,
At timing t4 ', it is assumed that the accelerator pedal 22 is further depressed by the driver from the previous position to re-accelerate the vehicle, and the accelerator opening changes from θa1 to θa2. Then, the CPU 33 proceeds to step 101
And the target step position T as the target step position TS
A value TS2 (= 117) larger than S1 is calculated (see FIG. 4).

In the processing routine started at timing t5, in the determination of step 103, the deviation TS2-MS between the target step position TS2 and the actual step position MS =
117−105 = 12 (≧ 0)
The value obtained by adding “1” to the rotation speed SPDL (= 3) of
Since it is larger than 4), the CPU 33 determines in step 104 whether the flag STATUS is “3”.
This flag STATUS is set to "1" in step 110.
, The CPU 33 proceeds to step 111, where the rotation speed SP of the step motor 15 at that time is set.
DL (= 3) is used as it is as the rotation speed SPDL.

Next, the CPU 33 sets the flag STATUS to "2" in step 112, and subtracts "1" from a predetermined count value CNT set by the acceleration prohibition counter set in step 110. (N-1) is set as a new count value CNT. And
The CPU 33 proceeds to step 113 and executes step 1
It is determined whether the count value CNT at 12 is equal to or less than “0”. When the count value CNT is larger than “0”,
The CPU 33 compares the rotation speed SPDL (= 3) at that time with “0” in step 106 of FIG.
In step 7, "1" is added to the actual step position MS (= 105) at that time, and the addition result (= 106) is set as a new actual step position MS. The CPU 33 proceeds to step 108
Then, the excitation coil of the step motor 15 is energized for a time determined by the rotation speed SPDL (= 3). Thus, the step motor 15 rotates at the same speed (constant speed) as the rotation speed SPDL at the timing t4.

In the processing after the timing t6, although the actual step position MS increases by "1" at step 107, the rotation speed SPDL does not change and the state of SPDL = 3 is maintained. Also, the count value CNT by the acceleration prohibition counter decreases by “1”. This state continues for a period up to the timing t9.
When NT becomes "0", the CPU 33
It is determined that it is necessary to end the constant speed rotation of No. 5, and the flag STATUS is set to "3" in step 114. Thus, the rotation speed of the step motor 15 can be increased. In step 114, the flag STAT
After setting the US, the CPU 33 performs the processing of step 106 and subsequent steps.

At the timing t9 when the constant speed rotation of the step motor 15 is completed, the target step position TS2 = 117, the actual step position MS = 110,
The rotation speed SPDL = 3 and the flag STATUS = 3. Therefore, at the next timing t10, the determination in step 102 is TS2-MS = 117-11
0 = 7 (≧ 0). This value (= 7) is equal to the rotation speed S
Since it is larger than the value (= 4) obtained by adding “1” to PDL (= 3), the CPU 33 determines that the current rotation speed of the step motor 15 can be increased (accelerated), and in step 104 It is determined whether or not the flag STATUS is “3”. Since the flag STATUS has been set to "3" in step 114, the CPU 33 proceeds to step 105, in which the step motor 1
A value (= 4) obtained by adding “1” to the rotation speed SPDL (= 3) of No. 5 is set as a new rotation speed SPDL. And
The CPU 33 determines in step 106 of FIG.
Since PDL (= 3)> 0, "1" is added to the actual step position MS at that time in step 107, and the addition result (= 111) is set as a new actual step position MS.
The CPU 33 determines in step 108 that the rotation speed SPDL (=
The excitation coil of the step motor 15 is energized for a time determined by 3), and this processing routine is temporarily terminated.

In the processing routine started at the timing t11, the rotation speed SPDL = 5 and the actual step position MS = 112. In the processing routine started at the next timing t12, TS2-MS (= 117−112 =
5) is the same as SPDL (= 5). For this reason, CP
U33 proceeds to step 115 and sets the value to the rotation speed S.
Used as PDL. Therefore, by the processing in step 108, the step motor 15 rotates at the same speed as the rotation speed SPDL at the timing t11, that is, at a constant speed. In this processing routine, the actual step position MS = 113 in step 107.

Then, in the processing routine started at the next timing t13, the deviation TS2-MS (= 117-113) = 4 between the target step position TS2 and the actual step position MS is determined in the judgments of steps 103 and 109. When the rotation speed of the step motor 15 becomes smaller than the rotation speed SPDL (= 5), the CPU 33 in step 110 subtracts “1” from the rotation speed SPDL (= 5).
4) is set as a new rotation speed SPDL, the flag STATUS is set to "1", and the count value CNT by the acceleration prohibition counter is set to a predetermined value n. And
The CPU 33 determines in step 107 that the actual step position MS (=
113) is added to “1”, the addition result “114” is set as a new actual step position MS, and the excitation coil of the step motor 15 is energized for a time determined by the rotation speed SPDL (= 4) in step 108. As a result, the throttle valve 14 rotates in the valve opening direction in a decelerated state.

In the processing routine started after timing t14, although the actual step position MS increases by "1" at step 107, the rotation speed SPDL decreases by "1" at step 110. Slowly decelerates. This deceleration state is at timing t1.
Continue until 6 ends. Then, in the processing routine started at timing t17, the actual step position MS = 11
7 and coincides with the target step position TS, and the rotation speed S
PDL becomes “1”.

In the next processing routine, since the rotational speed SPDL becomes 0 in step 110, the CPU 33 proceeds to step 108 as it is after the processing in step 106, and energizes the exciting coil of the step motor 15,
This processing routine ends once. As a result, the step motor 15 maintains the current step position, and as a result, the throttle valve 14 stops at a desired angle. This state is maintained until the depression amount of the accelerator pedal 22 is changed and the target step position TS2 changes.

Next, a case will be described in which the driver releases the accelerator pedal 22 from its previous position due to the vehicle deceleration at the timing t0a in FIG.

First, the CPU 33 executes step 101 in FIG.
In FIG. 4, the accelerator opening θ at that time is obtained from the map of FIG.
The target step position TS3 (= 93) according to a3 is calculated. In the determination in step 102, the deviation TS3-MS between the target step position TS3 and the actual step position MS = 9.
3-100 = -7 (<0). Therefore, the CPU 3
3 is a stepping motor 15 in the direction of closing the throttle valve 14
Is determined to be necessary, and step 10 in FIG.
Move to 3a. The processing after step 103a is
Since the processing is basically the same as the processing of steps 104 to 115 in FIGS. 6 and 7 described above, in FIG. 8, a is added to the step number of the corresponding processing and the description is omitted. However, in step 103a, it is determined whether the deviation between the target step position TS3 and the actual step position MS is equal to or less than a value obtained by subtracting a predetermined value (in this case, “1”) from the rotation speed SPDL of the step motor 15. . Step 1
In 05a, a value obtained by subtracting “1” from the rotation speed SPDL of the step motor 15 is set as a new rotation speed SPDL. In step 107a, "1" is subtracted from the actual step position MS at that time, and the subtraction result is set as a new actual step position MS. In step 110a, "1" is added to the target step position TS at that time, and the addition result is set as a new target step position TS.

Thus, the step motor 15 is rotationally driven in an accelerated state during the period from the timing t0a to t3a, is rotationally driven in a decelerated state at the timing t4a, and has the same speed as that during the deceleration during the period from the timing t5a to t9a.
That is, it is driven to rotate at a constant speed. Further, during the period from the timing t10a to the timing t11a after the end of the constant speed driving, the step motor 15 is driven to rotate in the accelerating state, and is driven to rotate in the constant speed state at the timing t12 to the timing t13a.
During the period from t16a to t16a, the motor is driven in a deceleration state, and thereafter, the rotation is stopped after timing t17a.

As described above, in the present embodiment, the actual step position MS of the step motor 15 and the target step position TS
When the deviation is larger than a predetermined value, the switching time of the exciting coils A, B, A, and B is gradually shortened to accelerate the rotation of the step motor 15 (step). 105, 105a), when the deviation is equal to or smaller than a predetermined value, the switching time of the exciting coils A, B, A, and B is gradually increased, and the stepping motor 15
Is decelerated (steps 110 and 110a). When the acceleration and deceleration of the step motor 15 are sequentially performed, and the target step position TS changes due to a change in the amount of depression of the accelerator pedal 22 and re-acceleration is required continuously, The step motor 15 is driven at a constant speed at a drive speed at the end of deceleration for a predetermined time before the re-acceleration is executed (steps 111 to 114, steps 111a to 114a).

The time for the constant speed drive may be set longer than the cycle determined by the resonance frequency fc of the step motor 15, or may be set based on the time from the previous acceleration start to the transition to the constant speed drive. A possible method is to set the frequency as small as possible so that the time from the start of the previous acceleration to the start of the next re-acceleration is longer than the cycle determined by the resonance frequency fc of the step motor 15.

Accordingly, the step motor 15 is driven to rotate during the period from the end of the deceleration to the re-acceleration, and accordingly, the throttle valve 14 also rotates in the valve opening direction or the valve closing direction. For this reason, deceleration after the first acceleration is performed until the stepping motor 15 stops once, and the stopped state is maintained for a certain period of time (at timing t14 'in FIG. 9).
In this embodiment, the actual step position MS is compared with the improved technique in which re-acceleration is performed at timing t14'a) in FIG.
Can reach a target step position TS.

In this embodiment, the frequency f (= 1 / T1) when the period from the end of deceleration to the reacceleration is set to the period T1 when the period from the first acceleration to the reacceleration is set to the stepping motor 15 It was set in consideration of being lower than the resonance frequency fc. Therefore, unlike the prior art, the frequency f at the time of driving the step motor 15 is
5 is prevented from being coincident with the inherent resonance frequency fc of
As a result, step-out is prevented.

As described above, according to the present embodiment, it is possible to prevent loss of synchronism of the step motor 15 and to improve responsiveness when the throttle valve 14 is driven.

[0065]

As described above in detail, according to the present invention, it is necessary to re-accelerate continuously while accelerating and decelerating the step motor in order according to the deviation between the actual step position and the target step position. When the re-acceleration is performed, a predetermined time set such that the frequency when the period from the first acceleration to the re-acceleration is one cycle becomes smaller than the resonance frequency of the step motor before the re-acceleration is performed, Since the step motor is driven at a constant speed at the drive speed at the end of deceleration, it is possible to improve responsiveness and drive smoothly when driving the throttle valve, while preventing step-out of the step motor that drives the throttle valve. The effect is excellent.

[Brief description of the drawings]

FIG. 1 is a conceptual configuration diagram of the present invention.

FIG. 2 is a schematic configuration diagram showing a drive device for a throttle valve according to an embodiment of the present invention;

FIG. 3 is a diagram schematically showing a step motor.

FIG. 4 is a diagram showing a map in which a target step position with respect to an accelerator opening is defined in advance.

FIG. 5 is a diagram showing a relationship between time and a step position for explaining acceleration and deceleration of a step motor.

FIG. 6 is a flowchart illustrating acceleration / deceleration control of a step motor.

FIG. 7 is a flowchart illustrating acceleration / deceleration control of a step motor.

FIG. 8 is a flowchart illustrating acceleration / deceleration control of a step motor.

FIG. 9 is a diagram illustrating a relationship between time and a step position when a step motor is rotationally driven to a valve opening side of a throttle valve.

FIG. 10 is a diagram showing a relationship between a time and a step position when a step motor is driven to rotate to a valve closing side of a throttle valve.

FIG. 11 is a diagram for explaining a conventional technology and an improved technology, and is a diagram illustrating a relationship between time and a step position when a step motor is rotationally driven.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine as internal combustion engine, 5 ... Intake passage, 14 ...
Throttle valve, 15 ... step motor, 23 ... throttle position sensor as actual step position detecting means,
27: accelerator sensor as operating state detecting means, 32
... Driving circuit as motor driving means, 33 ... CPU, A, B, bar A, bar B constituting target step position calculating means, deviation calculating means, accelerating means, decelerating means and constant speed means
... Exciting coil, TS ... Target step position, MS ... Actual step position, f ... Frequency when the period from initial acceleration to re-acceleration is one cycle, fc ... Resonance frequency

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H02P 8/00-8/38 F02D 9/00-9/18 F02D 11/00-11/10 F02D 29/00-29 / 06

Claims (1)

(57) [Claims] 1. A throttle valve provided in an intake passage of an internal combustion engine so as to be openable and closable, a step motor connected to the throttle valve for driving the throttle valve to rotate, and energizing an excitation coil of the step motor sequentially. Motor driving means for rotating and driving a step motor by switching; operating state detecting means for detecting an operating state of the internal combustion engine; target step of the step motor according to an operating state of the internal combustion engine by the operating state detecting means Target step position calculating means for calculating a position, actual step position detecting means for detecting an actual step position of the step motor, actual step position by the actual step position detecting means,
A deviation calculating means for calculating a deviation from the target step position by the target step position calculating means; and a deviation by the deviation calculating means being larger than a predetermined value so as to make the actual step position coincide with the target step position. When it is larger, the switching time of the exciting coil by the motor driving means is gradually shortened, and an acceleration means for accelerating the rotation of the step motor, and a deviation by the deviation calculation means to make the actual step position coincide with the target step position. When the value is equal to or less than the predetermined value, the switching time of the exciting coil by the motor driving means is gradually increased, and a speed reducing means for reducing the rotation of the step motor is provided, according to a deviation between the actual step position and the target step position. Thus, acceleration of the step motor by the acceleration means and deceleration by the deceleration means are sequentially executed. If the target step position changes due to a change in the operation state of the internal combustion engine and re-acceleration by the acceleration means is required, the first acceleration is performed before the re-acceleration is executed. When the period from the start to the re-acceleration is set as one cycle, the step motor is driven at a constant speed at the drive speed at the end of deceleration by the deceleration means for a predetermined time set so that the frequency is smaller than the resonance frequency of the step motor. And a throttle valve driving device for an internal combustion engine.