JPH0771290A - Auxiliary air amount control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To suppress reduction of engine rotational speed caused by delay of auxiliary air from a FICD valve interlocked with a compressor. CONSTITUTION:When an air conditioner switch is turned on from off condition, the flow amount of an AAC valve is increased to a value obtained by adding a target rotational speed change equivalent value Q1 to the auxiliary air amount equivalent value Q2 of the FICD valve, and real operation of a compressor is started with a time delay of a prescribed T1. The FICD valve is opened simultaneously with start of compressor driving, and auxiliary air is also led from the FICD valve. Simultaneously, the flow amount of the AAC valve is reduced in a value subtracted the auxiliary air amount equivalent value Q2 of the FICD valve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auxiliary air amount control device for increasing or decreasing the intake air amount of an internal combustion engine in response to an external load such as a compressor for an air conditioner.

[0002]

2. Description of the Related Art In an internal combustion engine for an automobile, for example, a compressor for an air conditioner, a hydraulic pump for power steering, etc. are driven by the engine output. Therefore, when these external loads act on the internal combustion engine, the internal combustion engine remains as it is. The number of revolutions, especially the number of idle revolutions, fluctuates greatly. In addition, the target idle speed itself may be set higher than the normal time in order to secure the cooling capacity. Therefore, conventionally, an auxiliary air passage is provided by bypassing the throttle valve, an auxiliary air control valve is provided, and a required auxiliary air is introduced through the auxiliary air control valve when an external load is applied.

As the auxiliary air control valve for the external load, the first auxiliary air control valve and the second auxiliary air control valve are arranged in parallel with each other in order to prevent the individual capacities from becoming excessively large. Is generally provided. For example,
Variable controllable A commonly used for multiple external loads
There is known a configuration in which an AC valve and an ON-OFF type FICD valve provided corresponding to each external load such as a compressor are provided in parallel with each other.

The introduction of the auxiliary air amount by the AAC valve and the introduction of the auxiliary air amount by the FICD valve are both started at the same time when the external load is turned on, as shown in the time chart of FIG. Has become.
That is, in the case of a compressor for an air conditioner as an example, introduction of auxiliary air is started at the same time when the air conditioner switch is turned on.

However, as described above, the external load O
If the introduction of the auxiliary air is started at the same time as the N operation, the inflow of the auxiliary air is delayed as shown by the broken line. Therefore, the engine speed is temporarily changed by the load of the compressor acting at the same time when the air conditioner switch is turned on. Decrease and destabilize.

Therefore, in Japanese Patent Publication No. 2-52106, as shown in the time chart of FIG. 7, the actual start of operation of the compressor is delayed for a predetermined period after the air conditioner switch is turned on, and the first auxiliary air control valve is used. A configuration is shown in which the auxiliary air introduction is started at the same time when the air conditioner switch is turned on, and the auxiliary air introduction by the second auxiliary air control valve is started at the same time when the actual operation of the compressor is started.

[0007]

As described above, if the introduction of the auxiliary air by the first auxiliary air control valve is started prior to the actual operation of the compressor, the decrease in the rotational speed at the start of the operation of the compressor can be suppressed to some extent. However, the auxiliary air flow rate of the second auxiliary air control valve, which is turned on at the same time when the actual operation of the compressor is started, is always accompanied by a change in the load as shown by the broken line in FIG. A drop occurs. In particular, when the flow rate of the second auxiliary air control valve accounts for a large proportion of the total auxiliary air flow rate, a non-negligible reduction in the rotational speed occurs.

Generally, the first auxiliary air control valve is an AAC.
While the second auxiliary air control valve is controlled by the engine control unit as a valve, the second auxiliary air control valve is ON / OFF controlled by simply interlocking with the compressor regardless of the engine control unit as a FICD valve. O before starting the compressor operation
N operation is difficult because it involves changes in the entire system.

[0009]

As shown in FIG. 1, an auxiliary air amount control apparatus for an internal combustion engine according to the present invention includes a first auxiliary air control valve 1 for variably controlling the auxiliary air amount of the internal combustion engine,
A means 2 for detecting that the external load switch is in an ON state, and a delay means 4 for delaying the ON operation of the external load switch for an appropriate period to start the actual driving of the external load 3.
And a second auxiliary air control valve 5 provided corresponding to the external load 3 and introducing a predetermined amount of auxiliary air when the external load 3 is actually operated, and the second auxiliary air control valve 5 when the external load switch is ON. The amount of auxiliary air of the air control valve 5 and the amount of change in the target rotational speed are increased, and the amount of auxiliary air of the second auxiliary air control valve 5 is reduced when the second auxiliary air control valve 5 is turned on. Thus, it is provided with means 6 for controlling the first auxiliary air control valve 1.

[0010]

[Function] An external load switch such as an air conditioner switch is turned on
When actuated, at the same time, the auxiliary air amount of the first auxiliary air control valve 1 increases by an amount corresponding to the auxiliary air amount of the second auxiliary air control valve 5 and an amount corresponding to the change in the target rotational speed. This auxiliary air flows into the combustion chamber with some delay.

The external load 3 such as the compressor starts to be driven by the delay means 4 with a slight delay from the ON operation of the external load switch. At this point, sufficient auxiliary air is actually supplied, so that the rotation speed does not decrease. Then, the second auxiliary air control valve 5 is turned on at the same time when the driving of the external load 3 is started, and the introduction of a predetermined amount of auxiliary air is started.
At the same time, the auxiliary air of the first auxiliary air control valve 1 is
The amount of auxiliary air of the auxiliary air control valve 5 is reduced by an amount corresponding to the amount.

The start of the introduction of the auxiliary air by the second auxiliary air control valve 5 is also accompanied by some delay, but at the same time, the reduction of the auxiliary air by the first auxiliary air control valve 1 is also accompanied by some delay.
Both are offset, and the decrease in the rotational speed due to the delay is alleviated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 2 is a structural explanatory view showing a mechanical structure of the auxiliary air amount control device according to the present invention, in which the internal combustion engine 1
A throttle valve 13 is provided in one intake passage 12, and a first bypass passage 14 and a second bypass passage 15 are formed in parallel so as to bypass the throttle valve 13. The first bypass passage 14 has a first
An AAC valve 16 composed of an appropriate digital flow control valve is interposed as an auxiliary air control valve, and the second bypass passage 15 is turned on and off as a second auxiliary air control valve.
A FICD valve 17, which is an FF type solenoid valve, is interposed. The AAC valve 16 controls the flow rate of the auxiliary air according to the ON duty ratio of the drive pulse signal output from the control unit 26.
The FICD valve 17 has a fixed flow rate corresponding to the load of the air conditioner compressor (not shown).
Together with the compressor electromagnetic clutch 27, it is turned on and off via the air conditioner relay 25. That is, the FICD valve 17 is ON / OFF-controlled in a manner linked to actual driving / stopping of the compressor. In this embodiment, the AAC valve 16 is also used for feedback control of the auxiliary air amount for idle speed control, but an auxiliary air control valve for idle speed control is separately provided. Is also good.

Reference numeral 18 is an idle switch for detecting that the throttle valve 13 is at the idle opening degree, 19 is an air flow meter for detecting the engine intake air amount, 20 is a fuel injection valve, and 21 is a cooling water temperature of the internal combustion engine 11. A water temperature sensor for detecting, 22 is an air-fuel ratio sensor for detecting the richness of the air-fuel ratio, 2
The control unit 2 indicates a crank angle sensor 3 for detecting the engine speed, and an air conditioner switch 24 which is turned on when the compressor needs to be driven.
A digital microcomputer system 6 includes a CPU, a RAM, a ROM, and an I / O port, and based on the detection signals of the above-mentioned sensors, an AAC valve 16,
Auxiliary air flow rate by FICD valve 17 and fuel injection valve 2
The injection amount at 0, the ignition timing of the spark plug (not shown), etc. are controlled, and the delay control of the compressor is performed as described later.

The flowchart of FIG. 3 shows the contents of the auxiliary air amount control for the operation of the air conditioner compressor, which will be described below. It should be noted that this process is repeatedly executed at regular intervals. Further, FIG. 4 shows a time chart corresponding to this control.

First, in step 1, it is determined whether the air conditioner switch 24 is in an ON state or an OFF state,
Further, in steps 2 and 9, the state of the flag F is determined. The flag F indicates the ON / OFF state of the compressor. If the flag F is 0 in step 2, the air conditioner switch 24 is turned on, and if the flag F is 1 in step 9, the air conditioner switch 24 is turned on. OF
It is shown to F to have respectively inverted.

When the air conditioner switch 24 is turned from OFF to ON, the process proceeds to step 3 and the AAC valve 1
Increase the target flow rate value of 6. Specifically, as shown in (a) of FIG. 4, a target rotation speed change equivalent amount Q1 for increasing the rotation speed and an auxiliary air amount equivalent portion Q2 of the FICD valve 17 are set to a flow rate Q at that time. Change to the value added to. Then, in step 4, it is determined whether or not a predetermined time T1 has elapsed after the switch is inverted, and after the predetermined time T1 has elapsed, driving of the compressor is started (step 5) and the FICD valve 17 is turned on (step 6). ). At the same time, in step 7, the target flow rate value of the AAC valve 16 is decreased. Specifically, FIC
The value corresponding to the auxiliary air amount Q2 of the D valve 17 is changed to a reduced value. Further, in step 8, the flag F is set to 1.

On the other hand, the air conditioner switch 24 changes from ON to O
When inverted to FF, step 9 to step 10
Then, the flow target value of the AAC valve 16 is decreased.
Specifically, as shown in FIG. 4A, the value corresponding to the auxiliary air amount Q2 of the FICD valve 17 is changed to a reduced value.
Then, in step 11, it is determined whether or not a predetermined time T2 has elapsed after the switch is inverted, and after the predetermined time T2 has elapsed, driving of the compressor is stopped (step 12) and the FICD valve 17 is turned off (step 1).
3). At the same time, in step 14, the target flow rate value of the AAC valve 16 is changed. Specifically, the amount Q1 corresponding to the target rotational speed change that has been given up to that point is subtracted, and the amount Q2 corresponding to the auxiliary air amount of the FICD valve 17 is added. Further, in step 15, the flag F is set to 0.

Therefore, according to the above control, when the air conditioner switch 24 is turned from OFF to ON, as shown in FIG. 4, the auxiliary air amount is increased before the compressor load is actually applied, so that the compressor load is applied. The rotation speed is prevented from decreasing at the moment of starting. The auxiliary air amount by the AAC valve 16 actually increases with a delay, as shown by the broken line. Further, the FICD valve 17 is turned on at the same time when the actual operation of the compressor is turned on, and at the same time, the flow rate of the AAC valve 16 is reduced by the same amount, but at that time, the actual auxiliary air amount of the FICD valve 17 is In contrast to the increase with a delay, the actual decrease in the flow rate of the AAC valve 16 also has a delay as shown by the broken line, and the effects of the delay cancel each other out. In other words, FIC that turns on at the same time as the compressor
A decrease in the rotation speed due to the delay of the auxiliary air of the D valve 17 is reliably prevented.

The AAC valve 16 needs to allow a large amount of auxiliary air to flow in the initial stage, but during that period, the delay time T
The capacity of the AAC valve 16 is set to a particularly large value because the probability that the AAC valve 16 overlaps is extremely small when the AAC valve 16 is controlled to be close to full open due to other external loads and thermal conditions. do not have to. Also, F
Since the ICD valve 17 is linked to the compressor via the air conditioner relay 27, it is not necessary to change the entire system.

On the other hand, the air conditioner switch 24 is turned on → OF
At the time of F, as shown in FIG. 4, the auxiliary air amount is suppressed by the AAC valve 16 prior to the actual stop of the compressor, so that the increase in the rotation speed at the moment when the compressor is turned off is prevented. Particularly, as in the case of the above-described start-up, the delay in the change in the auxiliary air of the FICD valve 17 linked to the compressor is offset by the delay in the change in the flow rate of the AAC valve 16, so that the fluctuation in the rotational speed is further suppressed. It

Next, the time chart of FIG. 5 shows an embodiment combined with an external load, for example, ignition timing correction control according to ON / OFF of the compressor.

In this embodiment, the compressor O
Ignition timing correction is executed so as to advance the ignition timing at N time to suppress the reduction of the rotation speed, and retard the ignition timing at OFF of the compressor to suppress the increase of the rotation speed. Here, prior to the actual ON operation of the compressor, the auxiliary air amount is increased and the target rotation speed is set high by the AAC valve 16, so the ignition timing is once shifted to the retard side during the delay period T1. As a result, the advance angle is corrected at the same time when the compressor is turned on. Therefore, during the advance angle correction, a sufficient advance angle correction amount ΔADV can be secured without being restricted by the knocking limit, and the torque can be quickly raised at the moment when the compressor load is applied. In this embodiment, A after the air conditioner switch 24 is turned on
The flow rate of the AC valve 16 is gradually increased.

When the compressor is stopped, prior to this, the auxiliary air amount by the AAC valve 16 is reduced and the target speed is returned to a low set value, so that the ignition timing is delayed during the delay period T2. Once it shifts to the advance side, the retard angle is corrected from here. .

[0026]

As is apparent from the above description, according to the auxiliary air amount control device for an internal combustion engine of the present invention, the introduction of the auxiliary air is started prior to the ON operation of the external load. It is possible to suppress a decrease in the number of revolutions during the ON operation of.
In particular, the auxiliary air amount equivalent to the second auxiliary air control valve is given in advance by the first auxiliary air control valve, and the auxiliary air introduction by the second auxiliary air control valve is started when the actual external load is turned on. Since the flow rate of the first auxiliary air control valve is decreased by the same amount as the above, the delay of the auxiliary air from the second auxiliary air control valve is offset by the delay of the decrease of the flow rate of the first auxiliary air control valve, and the delay Rotational speed fluctuations due to are further suppressed.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention.

FIG. 2 is a structural explanatory view showing a mechanical structure of an embodiment of the present invention.

FIG. 3 is a flowchart showing a control flow of this embodiment.

FIG. 4 is a time chart showing a flow rate change and the like in this embodiment.

FIG. 5 is a time chart of an embodiment combined with ignition timing correction control.

FIG. 6 is a time chart showing the operation of a conventional auxiliary air amount control device.

FIG. 7 is a time chart showing an operation in a different conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... 1st auxiliary air control valve 2 ... Load switch detection means 3 ... External load 4 ... Delay means 5 ... 2nd auxiliary air control valve 6 ... Control means

Claims (1)

[Claims] 1. A first auxiliary air control valve for variably controlling an auxiliary air amount of an internal combustion engine, a means for detecting that an external load switch is in an ON state, and an appropriate delay from the ON operation of the external load switch. Means for starting the actual driving of the external load, a second auxiliary air control valve provided corresponding to the external load and introducing a predetermined amount of auxiliary air when the external load is actually operated, and the external load When the switch is ON, the amount of auxiliary air corresponding to the second auxiliary air control valve and the amount of change in the target rotational speed are increased, and when the second auxiliary air control valve is ON, the auxiliary air of the second auxiliary air control valve is increased. An auxiliary air amount control device for an internal combustion engine, comprising: a means for controlling the first auxiliary air control valve so as to reduce the amount corresponding to the amount.