JPH0260850B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a solenoid current control method for a solenoid valve for controlling the amount of intake air in an internal combustion engine, and in particular, to a method for controlling the solenoid current of a solenoid valve for controlling the intake air amount of an internal combustion engine, and in particular for controlling the engine speed during idling operation. For this purpose, it is possible to appropriately control the solenoid current for proportionally controlling the opening degree of the solenoid valve provided in the bypass passage that communicates the upstream and downstream of the throttle valve provided in the intake passage. The present invention relates to a solenoid current control method for a solenoid valve for controlling the intake air amount of an internal combustion engine.

(Prior art) Conventionally, during so-called idling operation, in which the throttle valve provided in the intake passage of an internal combustion engine continues to operate in a nearly closed state, a bypass passage provided in the upstream and downstream of the throttle valve is used. A solenoid valve controls the intake air amount of the internal combustion engine to control the engine speed (idle speed).

Details regarding such an idle speed control method can be found in, for example, Japanese Patent Application No. 137445/1983.
The outline is described below.

As shown in FIG. 2, the conventional idle speed control method uses a microcomputer 4 consisting of a central processing unit (CPU) 1, a storage device (memory) 2, and an input/output signal processing circuit (interface) 3.
In CPU1, first, by the following equation (1),
Calculate the solenoid current command value Icmd.

In order to calculate Icmd with the CPU 1, various sensors must be appropriately arranged and the outputs of these sensors must be supplied to the interface 3, but since this is well known, various sensors other than the thermoswitch 10 must be Illustrations are omitted.

Icmd=[Ifb(n)+Ie+Ips+Iat+Iac]×Kpad (1) Ifd(n) in equation (1) is a feedback control term calculated based on the flowchart of FIG. 3, which will be described later. Note that (n) indicates the current value.

The calculation contents of steps S41 to S46 in FIG. 3 are as follows.

Step S41: Read the reciprocal number (period) of the engine rotation speed or the amount Me(n) equivalent thereto.

Step S42...The read Me(n)
and the preset target idle speed
Calculate the deviation ΔMef from the reciprocal of Nrefo or the equivalent amount Mrefo.

Step S43...The Me(n) and the Me
Previous measurement value Me for the same cylinder as (n)
[If the engine in question is a 6-cylinder engine, Me
(n-6)] - that is, the rate of change in the period ΔMe
Calculate.

Step S44... Said ΔMe and ΔMef, integral term control gain Kim, proportional term control gain
Kpm, the integral term using the differential term control gain Kdm,
Ii, the proportional term Ip, and the differential term Id are calculated according to the calculation formulas shown in the figure, respectively. Note that each of the control gains is obtained by reading out those stored in the memory 2 in advance.

Step S45...Iai(n), Iai(n-
1) is added with the integral term Ii obtained in step S44. Note that the Iai(n) obtained here is the next Iai(n)
-1), so it is temporarily stored in the memory 2. However, if it is not stored in memory 2 yet, store a numerical value in memory 2 in advance similar to Iai, and convert the numerical value to Iai(n-1).
You can read it as .

Step S46...Calculated in step S45
Ip and Id calculated in step S44 are added to Iai(n), respectively, and the feedback control term is
Ifb(n).

The contents of each term other than Ifb(n) in equation (1) are as follows.

Ie…alternator generator (ACG) load, i.e.
Addition correction term that adds the scheduled value according to the ACG field current.

Ips...Additional correction term that adds the scheduled value when the power steering switch is turned on.

Iat...The selector position of the automatic transmission AT is the drive
(D) Addition correction term that adds the scheduled value when in range.

Iac...Additional correction term that adds a scheduled value when the air conditioner (hereinafter referred to as the air conditioner) is activated.

Kpad…Multiplication correction term determined according to atmospheric pressure.

Note that Icmd in equation (1) is calculated according to a TDC pulse generated by a known means when the piston of each cylinder reaches 90 degrees before top dead center.

Icmd calculated by the above equation (1) is output from the microcomputer 4, where it is converted into a control signal.

The control signal is applied to the base of the solenoid driving transistor 5. As a result, the current flowing through the transistor 5 and therefore the solenoid 7
The current flowing through the solenoid (solenoid current) is increased or decreased depending on the control signal.

In FIG. 2, the opening degree of a solenoid valve (not shown) is proportionally controlled according to the solenoid current controlled by a control signal (base current of transistor 5). The intake air amount corresponding to the internal combustion engine is supplied to the internal combustion engine, and the idle speed is controlled.

By the way, whether or not to add the correction term Iac during air conditioner operation regarding the above-mentioned equation (1) is usually determined by the following procedure.

When the temperature inside the car in which the air conditioner is installed exceeds a certain predetermined value, the thermoswitch 10 is turned on.
Further, when the temperature inside the vehicle falls below a certain temperature lower than the predetermined value, the thermoswitch 10 is turned off. The on/off signal of the thermoswitch 10 is supplied to the CPU 1 via the interface 3. As a result, when the thermo switch 10 is on, the CPU 1 creates a solenoid current command value Icmd by adding the correction term Iac stored in the memory 2 in advance, assuming that the air conditioner is operating. On the other hand, when the thermo switch 10 is off, it is assumed that the operation of the air conditioner has been stopped, and the correction value is
Create an Icmd that does not add Iac.

The actual operation of the air conditioner is that when the thermoswitch 10 is turned on, the electromagnetic clutch operates in response to this, and the compressor of the air conditioner is driven by the internal combustion engine, while when the thermoswitch 10 is turned off, the electromagnetic clutch is operated accordingly. , this is done by reversing this state.

That is, in the past, the addition or non-addition of the correction term Iac was generally done to match the actual on/off operation of the air conditioner.

However, with the method of adding the correction term Iac as described above, sufficient air is supplied into the cylinder,
In an internal combustion engine in which an air chamber is provided between a throttle valve and a cylinder in order to obtain high output, the following problem occurs.

In an internal combustion engine equipped with an air chamber, even if the opening of the solenoid valve is controlled based on the solenoid current command value Icmd, which is obtained by adding the correction term Iac according to the ON state of the air conditioner, the intake air will be drawn according to the valve opening. Air is first charged into the air chamber, and then gradually supplied into the cylinder. That is, even if the intake air amount is increased by controlling the valve opening degree, it takes time for this increase to be reflected in the cylinder. For this reason, the engine speed inevitably decreases immediately after the air conditioner is turned on.

On the other hand, when the air conditioner is turned off, contrary to the above, even if the amount of intake air decreases based on Icmd to which the correction term Iac is not added, the amount of air supplied to the cylinder is immediately reduced. Since the engine speed does not decrease, the engine speed will temporarily increase.

Therefore, conventionally, the following method has been adopted as a means to solve the above-mentioned problems.

That is, the solenoid current command value Icmd is calculated by adding or not adding the correction term Iac depending on whether the thermoswitch 10 is turned on or off, and the opening degree of the solenoid valve is controlled based on the Icmd, as described above. However, the air conditioner is actually turned on or off at a scheduled time later than when the thermoswitch 10 is turned on or off.

FIG. 4 is a flowchart for operating the air conditioner in such a manner that the actual operation of the air conditioner is delayed from when the thermo switch 10 is turned on/off. Hereinafter, this FIG. 4 will be explained with reference to the above-mentioned FIG. 2. The operation shown in FIG. 4 is started by an interrupt caused by a TDC pulse.

Step S1: Read the output signal of the thermo switch 10.

Step S2: It is determined whether the thermoswitch 10 is on based on the signal read in step S1. If the judgment is not established, step S8
The process proceeds to step S3, and when it is established, the process proceeds to step S3.

Step S3: It is determined whether the thermo switch 10 was turned off last time. If the determination is not satisfied, the process proceeds to step S6, and if it is true, the process proceeds to step S4.

Step S4...Timer Taka that operates for the scheduled time
Start.

Step S5: As shown by the broken line in FIG. 2, the microcomputer 4 outputs an electromagnetic clutch-off signal. Processing then returns to the main program.

Step S6: It is determined whether or not the timer Taca started at step S4 is in operation. When this determination is established, the process advances to step S5. On the other hand, when the scheduled operating time has passed and the timer
Step S7 when Taka is timed up
Proceed to.

Step S7: As shown by the broken line in FIG. 2, the microcomputer 4 outputs an electromagnetic clutch-on signal. Processing then returns to the main program. As a result, the electromagnetic clutch is actuated and the air conditioner compressor is driven by the internal combustion engine. That is, the air conditioner is actually turned on.

Step S8: It is determined whether the thermoswitch 10 was turned on last time. If the determination is not satisfied, the process advances to step S11, and if it is true, the process advances to step S9.

Step S9...Timer Tacb that operates for the scheduled time
Start.

Step S10...As shown by the broken line in FIG.
The microcomputer 4 outputs an electromagnetic clutch-on signal. Processing then returns to the main program. As a result, even when the thermoswitch 10 is switched from on to off, the air conditioner remains on.

Step S11: It is determined whether or not the timer Tacb started at step S9 is in operation. When this determination is established, the step S10 is performed.
Proceed to. On the other hand, when the scheduled operating time has elapsed and the timer Tacb has timed up, the process advances to step S5. Therefore, at this time, the compressor of the air conditioner is not driven by the internal combustion engine due to the processing in step S5, so that the air conditioner is actually stopped.

As described above, the solenoid current command value Icmd is calculated by adding or not adding the correction term Iac depending on whether the thermoswitch 10 is turned on or off, and the opening degree of the solenoid valve is controlled based on the Icmd. The reason why the problem of the engine speed temporarily decreasing or increasing as described above does not occur when the actual on/off control of the air conditioner is delayed by the scheduled time is as follows.

The air conditioner actually turns on when the amount of air in the cylinder is increased by the correction term Iac.
This coincides roughly with the time when the engine torque that can handle the load of the air conditioner is obtained, and the time when the air conditioner stops operating is also the time when the amount of air in the cylinder actually decreases and the engine torque decreases accordingly. This is because they almost match.

In addition, FIGS. 5a to 5c show the output signal of the thermoswitch 10 described above and the solenoid current command value Icmd.
and a waveform diagram (time chart) showing an example of the mutual relationship between electromagnetic clutch on/off signals.

(Problems to be Solved by the Invention) The above-described conventional techniques had the following problems.

AT vehicles that supply the output of the internal combustion engine to the drive wheels via an automatic transmission (AT);
There are MT cars that use a manual transmission (MT). In an AT vehicle, when the selector position of the automatic transmission AT is in the D range, even if the vehicle is idling with the throttle valve closed, when the brake is turned off, the vehicle gradually begins to run at a low speed while remaining in the idling state.

In addition, even in a manual transmission car, if the engine has a large torque, if you put it in a low gear and gradually engage the clutch without opening the throttle valve, it will gradually slow down to a lower speed while it is in idle operation, just like the AT car. Start running.

By the way, during idling operation when the solenoid valve is performing engine rotational speed feedback control, when the engine is in in-gear and running at low speed, the actual air conditioner is activated with a scheduled time delay compared to the increase/decrease in the amount of intake air. In reality, the amount of air in the cylinder increases before the load on the air conditioner is applied, and the load on the air conditioner increases even though the amount of air in the cylinder decreases. As a result, the engine torque fluctuates when the amount of intake air increases or decreases. For this reason, the fluctuations in the engine torque were felt as a shock by the occupants of the vehicle, giving them a very unpleasant feeling.

Note that such a state is the same even when the vehicle is idling in the in-gear state and when the vehicle is not running with the brakes applied.

The present invention has been made to solve the above-mentioned problems.

(Means and operations for solving the problem) In order to solve the above problem, the present invention provides a correction term when the thermoswitch is turned on or off.
Without controlling the opening degree of the solenoid valve and therefore the amount of intake air based on the solenoid current command value Icmd with or without addition of Iac, the air conditioner is actually operated after the thermoswitch is turned on. During the period until the thermo switch starts operating, or after the thermo switch is turned off until the air conditioner actually stops, the intake air amount is calculated based on Icmd, which is the sum of the control amount Iaco, which is smaller than the correction term Iac. When the air conditioner actually starts or stops, the Icmd added with the above Iac is added.
Another feature is that the intake air amount is controlled based on Icmd with the above-mentioned Iaco not added.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a flowchart illustrating the operation of an embodiment of the present invention. Also, Fig. 6 b, a, c
is a waveform showing an example of the mutual relationship between the solenoid current command value Icmd determined based on the correction term (control amount) Iac determined by this embodiment, the output signal of the thermoswitch, and the electromagnetic clutch on/off signal. This is a time chart.

A specific example of the solenoid current control device that executes the operations shown in the flowchart of FIG. 1 is the same as that shown in FIG. 2 described above, so its illustration will be omitted and reference will be made to FIG. Further, the method of controlling the air conditioner is performed in the same manner as in FIG. 4 above. The operation of the flowchart of FIG. 1 starts with an interrupt caused by a TDC pulse.

Step S1: It is determined whether the output signal of the thermoswitch 10 is in the on state as shown in FIG. 6a. This determination is made in step S of FIG.
1, it is done from the already read signal. If this determination is not satisfied, the process proceeds to step S5, and if it is true, the process proceeds to step S2.

Step S2: It is determined whether or not the timer Taca started in step S4 of FIG. 4 is in operation. If this determination is not satisfied, that is, if the scheduled operating time has elapsed since the thermoswitch 10 was turned on and the timer Taca has timed up, the process advances to step S4. At this time, as is clear from step S7 in FIG. 4 and FIG. 6c, an electromagnetic clutch-on signal is output from the microcomputer 4, and the air conditioner is actually activated. On the other hand, if the determination in step S2 is positive, as is clear from step S5 of FIG. 4 and FIG.

Step S3...The control amount Iaco, which is smaller than the correction term Iac added when the air conditioner is actually activated, is set to Iac.
Set as . Processing then returns to the main program. Therefore, Icmd at this time is the 6th
As is clear from Figure b, for example, Ifb(n) has Iaco
The value is the sum of the . This Icmd is converted into a control signal and output from the microcomputer 4.

Step S4...The correction term Iac to be added when the air conditioner is actually operated is set as Iac. Processing then returns to the main program. Therefore, Icmd at this time is, for example, as clear from Figure 6b.
It is the value obtained by adding Iac to Ifb(n). This Icmd is then converted into a control signal and output from the microcomputer 4.

Step S5: It is determined whether or not the timer Tacb started at step S9 in FIG. 4 is in operation. If this determination is true, it is assumed that the air conditioner is still operating, as is clear from step S10 in FIG. 4 and FIG. 6c, and the process proceeds to step S3. On the other hand, if the scheduled operating time has elapsed since the thermo switch 10 was turned off and the timer Tacb has timed up, step S is executed.
Proceed to step 6. At this time, as is clear from step S5 in FIG. 4 and FIG. 6c, an electromagnetic clutch-off signal is output from the microcomputer 4, and the air conditioner is turned off.

Step S6: Set the correction term Iac to 0.
Processing then returns to the main program. Therefore, Icmd at this time is, for example, only the value of Ifb(n), as is clear from FIG. 6b.
This Icmd is converted into a control signal and output from the microcomputer 4.

In addition, in the above explanation, the control amount Iaco is a constant control amount with a smaller value than the correction term Iac added when the air conditioner is actually operated, but in the present invention, Iaco does not necessarily have to be a constant value. do not have. For example, Iaco from when the thermo switch 10 is turned on until the air conditioner actually operates is a control amount that linearly reaches the value of Iac from 0, whereas after the thermo switch 10 is turned off, the air conditioner actually stops operating. Iaco until the state is reached may be a control amount that linearly decreases from the value of Iac to 0.

(Effects of the Invention) As is clear from the above description, according to the present invention, the following effects are achieved.

(1) In the present invention, the actual on/off control of the air conditioner is performed with a scheduled time delay compared to the on/off state of the thermoswitch, whereas the scheduled control amount is controlled according to the on/off state of the thermoswitch. Solenoid current command value as addition or non-addition
In the solenoid current control method that determines Icmd, the control amount from the thermo switch on/off until the air conditioner is actually turned on/off is set to a value smaller than the control amount Iac that is added when the air conditioner is actually activated. As a result, even if the amount of intake air increases or decreases based on the control amount during idling operation in the in-gear state, the resulting fluctuation in engine torque becomes extremely small.
As a result, according to the present invention, the shock felt by vehicle occupants due to fluctuations in engine torque is substantially negligible.

(2) Also, as mentioned above, in the present invention,
Similar to the conventional example, the solenoid current command value Icmd is determined by adding or not adding the control amount depending on the on/off of the thermoswitch, and the opening degree of the solenoid valve is controlled based on the Icmd. The actual on/off control of the air conditioner is delayed by a scheduled time, so during normal idling operation when the air conditioner is not in gear, the engine speed may temporarily drop or rise when the air conditioner is turned on/off. No condition occurs.

[Brief explanation of the drawing]

FIG. 1 is a flowchart illustrating the operation of an embodiment of the present invention. FIG. 2 is a circuit configuration diagram showing a specific example of a solenoid current control device. Third
The figure is a flowchart for calculating the feedback control term Ifb(n). FIG. 4 is a flowchart explaining the operation of the air conditioner. FIG. 5 is a waveform diagram (time chart) showing an example of the mutual relationship between the output signal of a conventional thermoswitch, the solenoid current command value Icmd, and the electromagnetic clutch on/off signal. FIG. 6 is a waveform diagram (time chart) showing an example of the mutual relationship between the solenoid current command value Icmd determined based on an embodiment of the present invention, the output signal of the thermoswitch, and the electromagnetic clutch on/off signal. 1...CPU, 2...Memory, 3...Interface, 4...Microcomputer, 5...Solenoid driving transistor, 6...Battery, 7...Solenoid, 10...Thermoswitch.

Claims (1)

[Scope of Claims] 1. Provided in a bypass passage that communicates upstream and downstream of a throttle valve of an internal combustion engine, and whose opening degree is proportionally controlled according to a current flowing through a solenoid (hereinafter referred to as solenoid current). Solenoid valve and
an air conditioner that is driven by the internal combustion engine and is controlled on/off based on the on/off control of the thermoswitch; and a timer that operates for a scheduled time in response to the on/off of the thermoswitch.
In the method for controlling a solenoid current of a solenoid valve for controlling an intake air amount of an internal combustion engine, the method includes means for actually controlling on/off the air conditioner in response to a time-up of the timer, wherein the thermoswitch is turned on. During the operation of the timer from 1 to 3 until the timer times up, a solenoid current command value for the solenoid valve is calculated based on the first control amount, the solenoid current is controlled according to the command value, and the thermostat is operated. After a time has elapsed since the switch is turned on, a solenoid current command value of the solenoid valve is calculated based on a second control amount that is larger than the first control amount, and the solenoid current is controlled in accordance with the command value. A solenoid current control method for a solenoid valve for controlling the amount of intake air in an internal combustion engine, characterized by: 2. A solenoid current control method for a solenoid valve for controlling an intake air amount of an internal combustion engine according to claim 1, wherein the first control amount is a constant value. 3. A solenoid current control method for a solenoid valve for controlling an intake air amount of an internal combustion engine according to claim 1, wherein the first control amount is a value that increases over time. . 4. A solenoid valve that is installed in a bypass passage that communicates the upstream and downstream sides of a throttle valve of an internal combustion engine, and whose opening degree is proportionally controlled according to the current flowing through the solenoid (hereinafter referred to as solenoid current);
an air conditioner that is driven by the internal combustion engine and is controlled on/off based on the on/off control of the thermoswitch; and a timer that operates for a scheduled time in response to the on/off of the thermoswitch.
In the method for controlling a solenoid current of a solenoid valve for controlling an intake air amount of an internal combustion engine, the method includes means for actually controlling on/off the air conditioner in response to a time-up of the timer, wherein the thermoswitch is turned on. After the timer times up, a solenoid current command value for the solenoid valve is calculated based on the second control amount, the solenoid current is controlled according to the command value, and the thermoswitch is turned off. During the operation of the timer from to until the timer times out, a solenoid current command value of the solenoid valve is calculated based on a first control amount that is smaller than the second control amount, and the solenoid current command value of the solenoid valve is calculated according to the command value. A method for controlling a solenoid current of a solenoid valve for controlling an intake air amount of an internal combustion engine, the method comprising controlling the solenoid current. 5. A solenoid current control method for a solenoid valve for controlling an intake air amount of an internal combustion engine according to claim 4, wherein the first control amount is a constant value. 6. A solenoid current control method for a solenoid valve for controlling an intake air amount of an internal combustion engine according to claim 4, wherein the first control amount is a value that decreases over time. .