JPH03179148A - Engine speed controller for vehicle - Google Patents

Abstract

PURPOSE:To control a sudden rise of idling speed when an air conditioner is turned on by compensating an air flow rate at time of starting of the air conditioner for increment according to the discharge of a variable displacement compressor at a time when an engine is in the idling speed. CONSTITUTION:An operating state in an air conditioner with a variable displacement compressor is detected by a means 10 and discharge of this compressor by a means 102, respectively. Likewise, engine speed is detected by a means 103 and an idling state by a means 104, respectively. In addition, when the air conditioner is operated in this idling state of an engine, an increment compensation portion of air flow is set by a means 105. On the other hand, the air flow of the engine is regulated by a means 107. Then, the control value of this means 107 is calculated by a means 106 so as to become the desired engine speed when the engine is in the idling state, while the said control value is compensated for increment by means of the said increment compensation portion when the air conditioner is operated.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an engine speed control device for a vehicle equipped with a variable displacement compressor.

B. Conventional technology It is common to equip a vehicle with an air conditioner to keep the interior of the vehicle comfortable, but recently the refrigerant capacity is changed depending on the heat load of the vehicle. This type of variable displacement compressor, which is often used as a so-called variable displacement compressor, adjusts the angle of the swash plate of the compressor, that is, the inclination angle, according to the vehicle heat load to control the amount of refrigerant discharged per one rotation of the compressor. This reduces the burden on the engine in response to the vehicle's thermal load. Note that as the heat load increases, the inclination angle increases and the discharge capacity increases.

These variable displacement compressors are driven by the vehicle's engine, but the engine's rotational speed must be kept constant during idle conditions, regardless of the driver's will. Therefore, a rotation speed control device is provided.

Conventional rotation speed control devices perform idle rotation speed control by adjusting the opening degree of an AAC valve (auxiliary air flow control valve) installed in a passage that bypasses the throttle valve to achieve the target idle rotation speed. When the air conditioner is turned on, the opening of the AAC valve is increased by a certain amount to increase the idle speed to cope with the increase in compressor load (see, for example, Japanese Utility Model Application Publication No. 173533/1983).

The angle of inclination of a variable displacement compressor is not constant, and the load on the engine increases as the angle of inclination of the compressor increases. The rotational speed is uniformly increased accordingly.

C0 Problems to be Solved by the Invention However, in such a conventional engine speed control device, as shown in FIG. Since the correction amount (AAC/(corresponding to the air flow rate of Lube) was the same, especially when the air conditioner was turned on with the variable displacement compressor having a small inclination angle, that is, with a small load.

As shown in Figure 6 (b), there was a problem in that the AAC valve's increase in air conditioning capacity increased rapidly, causing the engine speed to overshoot with respect to the target speed, causing vibration and noise during idling. .

In addition, the reason why there are multiple overshoot modes in FIG. 6(b) is to illustrate that the variation in the rotation speed varies depending on the load when the air conditioner is turned on.

This is because variable displacement compressors have a significantly wider range of changes in the air conditioner load than fixed capacity compressors, and when the compressor is started to perform constant control over the target engine speed, it simply remains constant. This is because behavior in an overshoot region occurs due to increasing the amount.

A technical object of the present invention is to suppress overshoot of the idle rotation speed when the air conditioner is turned on, and to reduce vibration and noise, regardless of the vehicle heat load such as the outside temperature.

01 Means for Solving the Problems To explain with reference to FIG. 1, which is a diagram corresponding to the claims, the present invention is a variable capacity type that is driven by an engine to pump refrigerant, and whose discharge capacity is variably controlled according to heat load. An air conditioner detection means 101 detects the operating state of an air conditioner having a compressor, a capacity detection means 102 detects the discharge capacity of a variable displacement compressor, a rotation speed detection means 103 detects the rotation speed of the engine, and the engine is idle. idle detection means 104 for detecting that the
When the air conditioner operates while the engine is in an idle state, an increase setting means 105 sets an increase correction amount for the air flow rate when the air conditioner operates according to the discharge capacity of the variable displacement compressor; A control value is calculated for controlling the opening degree of the flow rate adjusting means 107 to adjust the engine rotation speed so that the target rotation speed is achieved when the engine is in an idle state, and when the air conditioner is activated. The control value calculating means 106 is provided for increasing the control value by the increase correction amount.

E0 action When the air conditioner operates while the engine is in an idle state, the air flow rate is increased in accordance with the discharge capacity of the variable displacement compressor at that time.

Since this increase correction corresponds to the load on the variable displacement compressor during idling operation, overshoot of the idling rotation speed when starting the air conditioner is suppressed, and vibration and noise are reduced.

In other words, when the load on the variable capacity compressor is small,
If the control value is simply increased by a fixed amount when the air conditioner is turned on, it will be too large and the engine speed will overshoot the target value. Therefore, only the load of the variable capacity compressor is increased to eliminate the overshoot and reduce engine vibration and Reduce noise.

F. Example An embodiment of the present invention will be described with reference to FIGS. 2 to 5.

FIG. 2 is an overall configuration diagram of a vehicle engine speed control device. In this figure, l is an engine mounted on a vehicle, intake air is supplied to each cylinder through an intake passage 2, and fuel is injected by an injector 3. The mixture in the cylinder is ignited and exploded by the discharge action of the spark plug 4.
It is discharged through the exhaust pipe 5.

Here, when the engine 1 is idling, the throttle valves 6a and 6b are in a closed state, and the intake air during idling is regulated by the AAC valve 7, and the idling speed is feedback-controlled to a specified value. Valve 7 is a conventional AAC valve, air regulator, F
I C'D (Fast Idle Control
A step motor type device is used to improve the accuracy of auxiliary air control and simplify piping. A.A.
Based on the auxiliary air amount control signal, the C valve 7 rotates a built-in step motor by the number of steps corresponding to the signal, moves the valve in the axial direction, and opens and closes the bypass passage 8.

The opening/closing amount is, for example, 128 steps, and the air flow rate in the bypass passage 8 changes according to the change in steps, and the idle rotation speed is adjusted.

Reference numeral 9 denotes a variable capacity compressor driven by the engine 1, and the compressor 9 is used to pump refrigerant in an air conditioner system for controlling air conditioning in the vehicle interior.
The discharge capacity is variably controlled according to the heat load in the vehicle interior. The variable displacement compressor 9 is already well known,
The capacity can be varied by controlling the inclination angle of the swash plate.For example, similar to the one disclosed in Japanese Patent Application Laid-open No. 158382/1982, a variable capacity compressor 9 discharges air into a casing chamber on the rear side of the piston. The angle of inclination of the swash plate connected to the piston is adjusted depending on whether pressure is introduced or suction pressure is introduced. In addition,
The control valve determines which direction to lead, and drive control of the control valve is performed by calculating a solenoid control current for the control valve called I190L from the vehicle thermal load. The calculation of the solenoid control current ISQL is performed by the A/C controller 10, and the A/C controller 10 uses a group of various temperature and solar radiation sensors that detect the heat load of the vehicle.
Calculate the optimal inclination angle based on the output from IE
iOL, is output to the compressor 9. Therefore, I
80L corresponds to the inclination angle and is a variable capacity compressor 9
This corresponds to the discharge capacity of

The value of the solenoid control current ISQL is input to the control unit 20.
In addition, a crank angle sensor 21 detects the rotational speed of the engine, an idle switch 22 detects that the engine 1 is in an idle state, an air conditioner switch 23 detects the operation of the air conditioner, and an opening of the throttle valve 6a. In addition to the signals from the throttle sensor 24 that detects the temperature, a water temperature signal, a vehicle speed signal, a transmission neutral signal, and a battery voltage signal are input, although the sensor is not shown. 20
is mainly composed of a microcomputer, and calculates a control value so that the rotation speed at idle reaches the target value based on the signals from each sensor mentioned above, and outputs the auxiliary air volume control signal to AA.
Output to C valve 7. In addition, control unit 2
o performs fuel injection control in addition to idle rotation speed control, but since it is not directly related to the present invention, the description thereof will be omitted.

Next, the effect will be explained.

Figure 3 is a flowchart of idle rotation speed control.
First, in step S1, it is determined whether the engine 1 is on (started) or not, and in step S2, it is determined whether the engine 1 is in an idle state. Step S
If NO in L or S2, return to step S1, and if YES, read engine speed N and actual air flow rate Q AAC of AAC valve 7 in step S3. Note that this air flow rate Q^^C is the auxiliary air 0 read based on the control signal.Then, in step s4, the flag is determined.

This flag is set immediately after the air conditioner is turned on when the engine is in an idle state, and is reset when the air conditioner is turned off.

At first, the flag=O, so the process advances to step S5.

Determine whether the air conditioner is on. When the air conditioner is turned on while the engine 1 is idling (immediately after being turned on), a flag is set in step S6, and the air conditioner load when the air conditioner is turned on is read in step S7. The magnitude of the air conditioner load is determined based on the value of the solenoid control current ISQL output from the A/C controller 10 when the air conditioner is turned on. In addition.

The air conditioner load is not limited to ISQL, but may be determined using the outside temperature Tout, the discharge pressure Pd of the variable displacement compressor 9, or the like. Next, in step S8, an increase correction bone Q□ when the air conditioner is turned on is looked up from the map shown in FIG. 4 based on the air conditioner load.

In step S9, the air flow rate (hereinafter referred to as control air flow rate) Q of the AAC valve 7 is determined as Q=QAAc10.

Calculate with the formula and end this routine. As a result, the opening degree of the AAC valve 7 increases by the amount corresponding to Ql, and the idle rotation speed increases to cope with the driving load of the air conditioner.

Here, since the increase correction bone Q1 is set according to the magnitude of the load, as shown in FIG. 5, a sudden increase in the idle rotation speed at the time of starting the air conditioner is suppressed and overshoot is prevented. That is, since only the load of the variable displacement compressor is appropriately increased, there is no overshoot in the rotational speed, and the rotational speed smoothly shifts to the target rotational speed. Therefore, vibrations during idling can be reduced, and noise represented by exhaust noise can also be reduced.

On the other hand, if the air conditioner is off in step S5, step 810. The engine speed N is compared with (N, +α) and (N x - α) at Sll. N1 is a target idle rotation speed (predetermined value) when the air conditioner is turned off, and α is a value corresponding to a dead zone during feedback control. N＞
When N1+α, the control air flow rate Q is changed to Q in step S12.
=QAAc-β (however, β is a correction value for feedback correction to the target value), and when N<N□-α, set Q=QAAC+β in step S13, and further N1α≦
When N≦N1+α, it is determined that the feedback correction is within the target range, and in step S14, Q=QAAc is set, the current routine is ended, and the process returns. Therefore, when the air conditioner is off, the air flow rate is feedback-controlled to a predetermined target idle rotation speed, and idle stability is maintained.

When the flag = 1 in step S4 above, that is, when the air conditioner is already on when engine l is idling (at the second and subsequent routines immediately after turning on the air conditioner),
Branching from step S4, step S15. In S16, the engine speed N is compared with (N2+α) and (N2-α), respectively. , N2 is the target idle rotation speed (predetermined value) when the air conditioner is turned on. When N>N2+α, in step S17, the control air flow rate Q is set to Q=QAAc-β, and the same process as in step 312 is performed. Also.

When N<N2-α, step S18 and step S13
Further, when N2-α≦N≦N2+α, the same process as step S14 is performed in step S19. Therefore, even when the air conditioner is on, the idle rotation speed is feedback-controlled.

After passing through any of steps S17 to S19, the air conditioner load is read in step S20 in the same manner as in step s7, and in step S21, a reduction correction amount Q'' of the air flow rate of the AAC valve 7 is set based on this air conditioner load. Q' is set by looking up, for example, the table map shown in FIG. 4. Therefore, the reduction correction amount Q' is a value that corresponds to the discharge capacity of the compressor 9. Next,
In step S22, it is determined whether the air conditioner is turned off,
If NO, return; if YES, first reset the flag in step S23, reduce the control air flow rate Q as Q=QAAC-Q' in step S24, and adjust the actual value of A'AC valve 7 in step S25. Air flow rate Q
An auxiliary air amount control signal that makes AAC equal to Q is output and returned.

Therefore, when the air conditioner is stopped, the air flow rate is corrected to be reduced according to the discharge capacity of the compressor 9 at that time (i.e., heat load), and in particular, the sudden drop in idle speed when the air conditioner is stopped is suppressed, and the target is smoothly achieved. It has the advantage that it can be shifted to the rotational speed. Note that when the air conditioner is turned off, the air flow rate may be simply corrected by a fixed reduction correction amount.

In the configuration of the above embodiment, the air conditioner switch 23 serves as the air conditioner detection means 101, the A/C controller 10 serves as the capacity detection means 102, the crank angle sensor 21 serves as the rotation speed detection means 103, and the idle switch 22 serves as the idle detection means 104. , the control unit 20, especially the third
Step S7 in the figure. S8 corresponds to the increase setting means 105, the control unit 20, especially each step in FIG.

G1 Effects of the Invention According to the present invention, the air flow rate when starting the air conditioner is corrected to increase according to the discharge capacity of the variable capacity compressor during idle rotation, so the air flow rate when the air conditioner is turned on is increased regardless of the heat load such as the outside temperature. It is possible to suppress a sudden increase in the rotational speed and prevent an overshoot with respect to the target rotational speed, and it is possible to reduce engine vibration and noise.

[Brief explanation of drawings]

FIG. 1 is a complaint correspondence diagram. 2 to 5 illustrate an embodiment of the vehicle engine speed control device according to the present invention, in which FIG. 2 is an overall configuration diagram, FIG. 3 is a flowchart of idle speed control,
FIG. 4 is a diagram showing a bone increase correction map for air conditioner load, and FIG. 5 is a diagram illustrating changes in rotation speed. FIG. 6 is a diagram illustrating problems with the conventional device. 1; Engine 7: AAC valve 8: Bypass passage 9: Compressor 10: A/C controller 20: Control unit 21: Crank angle sensor 22: Idle switch 23
: Air conditioner switch 101 : Air conditioner detection means 102 : Capacity detection means 1
03: Rotation speed detection means

Claims (1)

[Claims] an air conditioner detecting means for detecting the operating state of an air conditioner having a variable displacement compressor that is driven by an engine to pump refrigerant and whose discharge capacity is variably controlled according to heat load; A capacity detection means for detecting, a rotation speed detection means for detecting the engine rotation speed, an idle detection means for detecting that the engine is in an idle state, and a variable capacity type detection means for detecting when the air conditioner is activated when the engine is in an idle state. an increase setting means for setting an increase correction amount for the air flow rate when the air conditioner operates according to the discharge capacity of the compressor; a flow rate adjustment means for adjusting the air flow rate of the engine and changing the engine speed; and the engine is in an idle state. control value calculating means for calculating a control value for controlling the opening degree of the flow rate adjusting means so as to reach a target rotational speed when the air conditioner is in operation, and for increasing the control value by the increase correction amount when the air conditioner is activated; A vehicle engine speed control device comprising: