JPH0245637A - Throttle opening degree controller for internal combustion engine mounted on vehicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a throttle interval control jB device for an on-vehicle internal combustion engine, and more specifically, a pulse motor is connected to a throttle valve, and the throttle valve is opened and closed through the motor. The present invention relates to a throttle opening control device for a vehicle-mounted internal combustion engine to be controlled.

(Prior Art) It is well known that a pulse motor is connected to a throttle valve disposed in the intake passage of an internal combustion engine, and its opening and closing is controlled according to the operating state of the engine. The technique described in Japanese Patent Application Laid-Open No. 60-35141 can be mentioned. In this technology, the mechanical connection between the accelerator pedal and the throttle valve is completely separated, and the throttle valve is opened and closed only by the driving force of the pulse motor, but there is also a mechanical connection between the accelerator pedal and the throttle valve. A well-known method is to connect a pulse motor to the throttle valve in parallel with the throttle valve and control its opening and closing independently of the accelerator pedal operation.

(Problem to be Solved by the Invention) In any case, as long as the throttle valve is driven to open and close via a pulse motor, step changes in the intake air amount relative to the throttle opening can be avoided due to the characteristics of the pulse motor. First, you cannot expect smooth changes like those obtained when opening and closing via the accelerator pedal. The degree of this stepwise change is determined by the bore diameter of the engine intake passage (the area of the throttle valve) and the step angle of the pulse motor. In this case, since the intake passage bore diameter is designed based on various factors such as the planned engine output, it is difficult to change it only to eliminate step-like changes, and it is difficult to change the intake passage bore diameter based on various factors such as the planned engine output. Countermeasures such as increasing the number of poles or increasing the reduction gear ratio can be considered, but it cannot be denied that there are limits to this.

Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to provide a throttle valve for an on-vehicle internal combustion engine that allows minute control of the opening degree of the throttle valve when the throttle valve is driven via a pulse motor. An object of the present invention is to provide an opening control device.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides an accelerator pedal depression amount detection means for detecting the depression amount of an accelerator pedal arranged on the floor surface of the driver's seat of a vehicle, as shown in FIG. 1. An engine operating state detecting means 2 for detecting the operating state of the engine, inputting the outputs of the engine operating state detecting means and the accelerator pedal depression amount detecting means to determine the target opening degree of the throttle valve provided in the engine intake passage. Throttle opening target value setting means 3 for setting the value
, a motor command value calculation means 4 which inputs the output of the throttle opening target value setting means and calculates a command value of the pulse motor to eliminate the deviation from the actual opening; and inputs the output of the motor command value calculation means. In the throttle opening control device for an on-vehicle internal combustion engine, the device includes a pulse motor 5 that rotates as a pulse motor 5, and a throttle valve 6 that is connected to the pulse motor and opens and closes an engine intake passage in accordance with the rotation of the pulse motor.
When the deviation falls within a predetermined range, the drive of the throttle valve is switched from step angle control to duty control (command value is calculated).

(Function) By driving the throttle valve at an appropriate duty ratio, it is possible to obtain a resolution equivalent to less than one step angle of a pulse motor, and therefore the throttle opening can be controlled minutely to reduce the intake air amount. It can be controlled accurately.

(Example) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Second
The figure is a schematic diagram showing the overall throttle opening control device for an on-vehicle internal combustion engine according to the present invention. Referring to the figure, reference numeral 10 indicates the internal combustion engine. The internal combustion engine 10 is equipped with an intake passage 12, and intake air introduced through an air cleaner 14 attached to the tip side enters an intake manifold 18 while its flow rate is adjusted by the throttle valve 6 described above, and is used for fuel injection. Fuel is supplied through a valve 20, and a combustion chamber 24 is supplied through an intake boat where an intake valve 22 opens and closes.
flows into. The incoming air-fuel mixture is ignited by a spark plug (not shown) and combusted, driving the piston 26. After that, it passes through an exhaust boat opened and closed by an exhaust valve 28, enters the exhaust manifold 30, and enters the exhaust pipe (not shown). ) and then released outside the engine.

Further, an accelerator pedal 32 is arranged on the floor of the driver's cabin of the vehicle in which the internal combustion engine is mounted, and the pedal is biased to the idle position by a spring (not shown) and is pressed in response to the driver's depression. Rotate. As shown in the figure, the mechanical connection between the accelerator pedal and the throttle valve 6 is broken, and instead, the above-mentioned pulse motor 5 is provided near the throttle valve. The pulse motor is connected to the valve shaft 6a of the throttle valve via a clutch mechanism and a reduction gear mechanism (not shown) to drive the valve to open and close. Note that a return spring (not shown) is provided on the throttle valve shaft 6a, and always biases the throttle valve in the fully closed direction. The opening degree of the throttle valve is detected through a throttle sensor 40 consisting of a potentiometer or the like.

Furthermore, at an appropriate position downstream of the throttle valve in the intake passage 12,
A movie pressure sensor 42 that detects the pressure of intake air as an absolute pressure
Further, an intake temperature sensor 44 for detecting the temperature of intake air is provided on the downstream side thereof, and an atmospheric pressure sensor 46 for detecting atmospheric pressure is provided at an appropriate position upstream of the throttle valve. Further, an accelerator sensor 48, which is the above-mentioned accelerator pedal depression detection means, is provided near the accelerator pedal to detect its depression ft (accelerator opening degree), and at an appropriate position near the combustion chamber, it detects the cooling water temperature. A water temperature sensor 50 is provided, and a crank angle sensor 52 for detecting the crank angle of the engine is provided at an appropriate location such as in a distributor (not shown), and a crank angle sensor 52 for detecting the crank angle of the engine is provided at an appropriate location in the transmission (not shown). A vehicle speed sensor 54 is provided to detect the traveling speed. The outputs of these sensors are sent to a control unit 58.

Furthermore, this control device includes an ACG sensor 60 that detects the field current of an alternator (not shown), a power steering switch 62 that detects activation/inactivation of the power steering (not shown), and a near conditioner (not shown). ), a starter switch 66 that detects activation/non-operation of a starter (not shown), a battery voltage sensor 68 that detects the voltage of a battery (not shown), a shift lever ( A range selector switch 70 for detecting the range position (not shown) and a shift position switch 72 for detecting the shift position (gear) (for example, detected by referring to the solenoid excitation signal of the mission control unit) are provided for control. A brake switch 74, main switch 76, set switch 78, and resume switch 80 are also provided for powering the unit and for autocruise control.

FIG. 3 shows details of this control unit 58. In this unit, the analog output of the throttle sensor 40, etc. is input to a level conversion circuit 88, where it is converted to an appropriate level and then input to a microcomputer 90. It is converted into a digital value by the A/D conversion circuit 90a and the RA
Temporarily stored in M90e. In addition, the crank angle sensor 52
The digital outputs are waveform-shaped by a waveform shaping circuit 92 and input into the microcomputer via the input port 90b. CPU9 in a microcomputer
0c calculates a control value from these inputs according to the program stored in the ROM 90d as described later, sends it to the output circuit 94 via the output port 90r, and further outputs the control value to the pulse motor via the drive circuit 96 consisting of transistors, etc. 5, thereby controlling the opening and closing of the throttle valve 6. In the above description, the crank angle sensor 52 and the like other than the accelerator sensor 48 correspond to the engine operating state detection means, and the microcomputer 90 corresponds to the throttle opening target value setting means and the motor command value setting means.

Next, the operation of this control device will be explained with reference to the flow chart in FIG.

First, in S10, each part of the device is initialized.

Note that this operation is performed when the engine is started, and after that, 312
The following operation is repeated in a loop for a predetermined period of time, for example, every 10n+s.

Next, in S12, the previously calculated control value is output via an output routine (not shown), and then in S14, control parameters such as engine speed are read, and then in the next step 316, the throttle I/L opening degree is Search for the standard opening degree θTHM. This is the accelerator opening θAP and the engine speed N
Then, in step 318, it is determined whether or not the idle control area is reached. This is determined from the starter switch signal, range selector signal, vehicle speed, intake pressure, throttle opening, engine speed, etc., and especially when the engine speed is below the appropriately set deceleration speed and above the idle determination speed. It is determined that it is within the control range, and the process proceeds to S20 to calculate the idle opening degree θ1dle.

FIG. 5 is a flow chart showing a subroutine for calculating the idle opening.
At 00, the target rotation speed N r for feedback control
ef is searched and the deviation SN from the actual engine speed is calculated. FIG. 6 is an explanatory graph showing the target rotation speed Nref, and as shown in the figure (the target rotation speed is set to a different value depending on whether there is a load or not depending on whether it is in the D range or the N range.Such characteristics is stored as a table in the ROM 90d, and is searched using the water temperature T-.At the same time, in this step, the counter value N is searched according to the calculated deviation SN.As will be described later, this is to change the control cycle. In other words, the period of this control operation is basically 10m5.
However, when entering the feedback mode and duty mode, the length is set to 100 to 500 m5, so in this step, search how many times the fundamental period (N) to make the period at that time according to the deviation. It is something to keep. Specifically, a table (not shown) is stored in the ROM, and the table is searched based on the deviation. Therefore, in this table, the period is set in inverse proportion to the deviation; that is, when the deviation is small, slow control is sufficient, so it is long, and when the deviation is large, the period is set short to eliminate the difference quickly. has been done.

Therefore, if the value of N is, for example, 50, then 50 of the fundamental period
This means that the control period is twice as long as 500m5.

Next, in 5102, the water temperature increase correction θTW is stored in the ROM.
Then, in 5IO4, the load increase correction θLOAD of the near conditioner, etc. is similarly searched from the table. Set these values as appropriate.

Next, in 5106, it is determined whether or not the engine speed Ne exceeds a reference low speed N LOP that is appropriately set.
If not, the process proceeds to 5108 to output an emergency throttle opening and quickly increase the engine speed. This is an emergency measure in case the engine speed drops to a low level that cannot be achieved with normal control due to starting or panic braking.

If affirmative at 8106, it is then determined at 5110 whether dashpot control is necessary, and if it is determined to be necessary, the process proceeds to 5112 to gradually reduce the engine speed to avoid sudden changes in negative pressure. do. This is mainly to prevent the emission of unburned gas. Note that whether or not dashpot control is necessary is determined based on changes in engine speed.

If 5ilo is negative, feedback control or duty control will be entered. In that case, since the control cycle is changed, first 5114
At , it is determined whether or not this is the first time the control is entered. If affirmative, the process proceeds to 8116 and it is determined whether or not the deviation SN is within the duty control permissible rotation speed NDUTY. The retrieved N is set in the counter C1dle, and normal feedback control is performed in 5120. In feedback control, the throttle opening is determined based on the feedback basic amount θFB, which is set as appropriate, and the water temperature and load increase corrections θX and θLO.
Determine by adding up AD. When it is determined in 3116 that the deviation is within the allowable rotation range, the process proceeds to 5122, where the water temperature T- is determined to be the duty control allowable water temperature T.
It is determined whether wDtlTY is exceeded or not, and if it is not exceeded, the feedback control is stopped, and if it is exceeded, N is set in the counter C1dle in 5L24, and then the process proceeds to 8126 to shift to duty control. That is, in this control operation, feedback control is performed until the deviation between the actual rotation speed and the target rotation speed becomes small, and when the deviation becomes small, the shift to duty control, which will be described later, is performed, and the throttle opening is further adjusted. to minutely control. In this sense, the duty control allowable rotation speed N DEITY is
For example, it is set to a small value such as 150 rpm. In this case, the reason why the water temperature is judged at 5122 is that there is no point in performing precise duty control since the correction increase is large in a low water temperature state. Therefore, this water temperature T wDUTY
is appropriately set to a value that is sufficient to distinguish it.

Figure 7 is a flowchart showing the duty control subroutine.
Before going into the explanation of this flow chart, this duty control will be briefly explained with reference to FIGS. 8 and 9. As mentioned above, duty control is entered when the actual engine speed approaches the target speed and the deviation becomes small, as shown in the lower part of Fig. 8. While the previous feedback control (or LOP mode, DP mode) controls the rotation amount of the pulse motor to one step angle or more, it controls the smaller rotation of less than one step angle, thus reducing the engine rotation speed. This is to minutely control the That is, for a certain step angle n and the next step angle n+1, the rotation direction is switched in the middle of the control cycle, and as a result, as shown by the broken line, rotation of less than one step angle is possible. In addition, in the embodiment, l step angle is 0 when converted to throttle opening.
．． It corresponds to 36 degrees. Also, in Fig. 8, the control period is
As mentioned above, both feedback control and duty control have a length of 100 to 500 m5 depending on the value of N mentioned above. Figure 9 explains this control in more detail. For convenience of understanding, the pulse motor is assumed to have four phases of φ1 to φ4, as shown in FIG. Figure (b) shows an example of normal two-phase excitation, and as is well known, when rotating in a predetermined direction, for example, the positive direction, φ1 to φ4 are excited in two phases at a time. be. The same figure (C) shows the duty control according to the present invention. In this case, for example, after exciting φ4.1, φ1 and 2 are excited to rotate in the positive direction, and then, Excite φ4.1 again. As a result, the pulse motor rotates in reverse because φ4, 1 in the reverse rotation direction is excited without φ2, 3 adjacent in the forward rotation direction being excited. Next, if φ1.2 is excited, it will be reversed again in the positive direction, and as described above, by alternately exciting the left and right phases around an arbitrary phase, the pulse motor can be moved within a range of one step angle. You can make it swing inside. In this case, as shown in the figure, if the time for exciting φ1 and φ2 is set and the entire period is T, it can be understood as duty control, and it can be understood as duty=t/TX100%. Therefore, by appropriately determining t/T, a desired amount of rotation can be obtained within a range of less than one step angle, as shown by the broken line at the top of FIG. That is, in conventional pulse motor control, it was not possible to obtain rotation of less than one step angle, but with the control according to the present invention.
(As mentioned above, this is called "duty control"), which makes this possible.

Furthermore, FIG. 9(d) shows an example of duty control over a range of two step angles. In this case, for example, φ1,2
After excitation, φ2, 3, φ3.4, and then φ
2, 3, and φ1.2 in the opposite direction, and then again in the positive direction as φ2, 3. Therefore, in this example as well, t/T
By appropriately setting , a desired amount of rotation can be obtained within the range of two step angles. It goes without saying that control over a range of three step angles is also possible in the same way. In the above, the duty resolution is specifically expressed as control period (CPU synchronization timing)/period TX100%, and its minimum value is, for example, 10
ms/500m5X 100=2%.

So, returning to the flow chart in Figure 7, we have the following explanation:
At 5200, period T is retrieved from water temperature T-. 1st
As shown in Figure 0, the period is set in inverse proportion to the water temperature, and such characteristics are stored as a table in the ROM.

The reason why the period becomes shorter as the water temperature increases is because the target rotation speed is set in inverse proportion to the water temperature, as shown in FIG. In other words, the lower the engine speed, the greater the amount of variation in the intake air amount when the throttle opening changes. This is because it needs to be shortened and finely controlled.

Subsequently, in step 5202, the above-mentioned on-time is calculated from the deviation SN, and the step angle number is searched. FIG. 11 shows the step angle number corresponding to the deviation. Needless to say, the step angle is made proportional to the deviation because it is desirable to increase the number of step angles as the deviation becomes larger.In the illustrated example, for a deviation of 50 to 99 rpn+, the range of 2 step angles is Duty control will be performed using

This characteristic is also stored as a table in ROM.
Returning to the flow chart in FIG. 5, at 5122, one of the modes (3108, 112, 120, 126)
The control value determined in step 1 is set as the idle control opening degree θ1dle, and the process returns to the main routine. Furthermore, when 5114 is negative, the process moves to 5130 and decrements the counter value, and then jumps to 8128 and changes the control value every time the loop is executed until it is determined that the counter value has reached zero in 5132. Return to the main routine without any problem. Therefore, 513
When it is determined in step 2 that the value has reached zero, the process moves to 8116, and the process proceeds to feedback mode or duty mode to newly determine the control value. That is, since the main routine in FIG. 4 is looped for 10+s, when the subroutine in FIG. Once you have determined the control value, you can simply follow it and set it to 50 without changing it.
This waits until 0m5 has elapsed.

Furthermore, returning to FIG. 4, if it is determined in S18 that it is not in the idle control range, the process proceeds to S22, and the predetermined opening degree θ is
The idle opening is set at 1 dle-ref. This predetermined opening degree is, for example, 10 degrees (however, WOT=84 degrees), which is the upper limit opening degree in idle control.

Subsequently, in S24, it is determined whether or not the vehicle is in the auto cruise control range. This is the brake switch 74 mentioned above.
, the main switch 76 and the like. If it is determined that the vehicle is in the cruise control range, the auto cruise opening degree θc is adjusted as appropriate in S26 to maintain the set vehicle speed.
ru is calculated, and if not, the auto cruise opening degree is set to zero at 32B.

Subsequently, in S30, the target opening degree θTll0 is calculated. This is the opening calculated so far, that is, the standard opening θ
The maximum value is selected from among THM, idle opening degree θ1dle, and auto cruise opening degree θcru. By taking the maximum value in this manner, it is possible to realize a throttle opening that satisfies all of the idle control range and auto cruise control range, even in a driving state where the range overlaps with the idle control range and the auto cruise control range. Note that the selected maximum value is indicated by the opening degree, so in this step, it is converted into the number of pulses by dividing it by a predetermined number (opening degree per pulse).

Finally, proceed to S32, calculate the difference between the target value and the current opening degree, determine the control value θCMD (displacement amount), and proceed to S32 again.
Loop to 2.

In this embodiment, as described above, the throttle opening is focused on the target value through feedback control, and after the deviation becomes small, the throttle valve itself is controlled to vibrate by duty control, thereby preventing rotation of less than one step angle. Since the throttle opening is configured so as to obtain the desired throttle opening degree, it is possible to precisely realize the desired throttle opening degree.

Although the present invention has been described with reference to a mechanism in which the mechanical connection between the accelerator pedal and the throttle valve is completely separated, the present invention additionally provides a pulse motor while leaving the mechanical connection intact. Needless to say, it is also valid when attached to things.

(Effects of the Invention) In the throttle opening control device for an on-vehicle internal combustion engine according to claim 1, the motor command value calculation means changes the drive of the throttle valve from control based on the step angle to duty when the deviation falls within a predetermined range. Since the configuration is configured to calculate the command value as if switching to control, when controlling the drive of the throttle valve via the pulse motor, the rotation of the motor can be controlled within a range of less than one step angle. can be minutely controlled. Specifically, this duty control is performed by switching the direction of movement of the throttle valve at predetermined time intervals.

Further, in the device according to claim 3, the duty ratio of the control is made variable according to the operating state of the engine, so that the throttle control can be performed more effectively in response to the operating state of the engine. I can do it.

[Brief explanation of the drawing]

Fig. 1 is a diagram corresponding to the claims of the present invention, Fig. 2 is a schematic diagram showing the overall throttle opening control device for an in-vehicle internal combustion engine according to the present invention, and Fig. 3 shows details of the control unit therein. The block diagram, FIG. 4 is a flow chart showing the operation of the device, FIG. 5 is a flow chart showing the idle opening calculation subroutine therein, and FIG. 6 is a flow chart showing the characteristics of the target rotation speed used for the calculation. 7 is a flow chart showing the duty control subroutine of FIG. 6,
FIG. 8 is a waveform diagram explaining duty control, FIG. 9 is a timing chart similarly explaining duty control, and FIG. Similarly, FIG. 11 is an explanatory graph showing the characteristics of the number of step angles used in the calculation. 1... Accelerator pedal depression amount detection means (accelerator sensor 4B), 2... Engine operating state detection means (crank angle sensor 52, etc.), 3... Throttle opening target value setting means (microcomputer 90) , 4...Motor command value calculation means (microcomputer 90), 5...
- Pulse motor, 6... Throttle valve, 10... Internal combustion engine, 12... Intake path, 32... Accelerator pedal, 40... Throttle sensor, 42... Intake pressure sensor, 44...・Intake temperature sensor, 46... Atmospheric pressure sensor, 48... Accelerator sensor, 50... Water temperature sensor,
52... Crank angle sensor, 54... Vehicle speed sensor,
58... Control unit, 60... ACG sensor, 6
2... Power steering switch, 64... Air conditioner switch, 66... Starter switch, 68... Battery voltage sensor, 70... Range selector switch, 72
...Shift position switch, 74...Brake switch, 76...AC main switch, 78...
AC set switch, 80... AC resume switch, 90... Microcomputer Figure 4 Applicant Honda Motor Co., Ltd. Agent Patent Attorney Yoshi 1) Toyota Figure 6 Figures (a) (b) Figure 9 Figure (C) (d) Figure 10 Water temperature TW Figure 11 +00 '50 & 85 ~ (rpm) 8. Contents of amendment (1) The detailed description of the invention in the specification is amended as follows.
The "inverse proportion" in the first line of page 19 of the specification is corrected to "proportionality." ■Correct "short" to "long" in the third line of page 19 of the specification. ■Page 19 of the specification, lines 7 to 8, “From Naruko,”
In relation to FIG. 6, since the low temperature side is the low rotational speed side, the term "fine by shortening the cycle" is corrected to "fine by shortening the cycle." 2) Modify Figure 10 of the drawing as shown in the attached sheet.

Claims (3)

[Claims] (1) a. Accelerator pedal depression amount detection means for detecting the depression amount of an accelerator pedal arranged on the floor surface of the vehicle driver's seat; b. engine operating state detection means for detecting the operating state of the engine; c. Throttle opening target value setting means for inputting the outputs of the engine operating state detecting means and the accelerator pedal depression amount detecting means to set a target value of the opening of a throttle valve provided in the engine intake passage; d. Motor command value calculating means inputting the output of the throttle opening target value setting means and calculating a command value of the pulse motor in order to eliminate the deviation from the actual opening; e. a pulse motor that rotates by inputting the output of the motor command value calculation means; and f. A throttle opening control device for an on-vehicle internal combustion engine comprising: a throttle valve connected to the pulse motor and opening/closing an engine intake passage according to the rotation of the pulse motor; 1. A throttle opening degree control device for an on-vehicle internal combustion engine, wherein a command value is calculated so as to switch the drive of the throttle valve from step angle control to duty control. (2) The throttle opening control device for an on-vehicle internal combustion engine according to claim 1, wherein the duty control is performed by switching the moving direction of the throttle valve at predetermined time intervals. (3) The throttle opening control device for an on-vehicle internal combustion engine according to claim 2, wherein the duty ratio of the duty control is made variable according to the operating state of the engine.