JPH03112717A - Air conditioning load detection device for vehicle - Google Patents

Abstract

PURPOSE:To eliminate an effect due to fluctuation elements than an air compres sor by detecting an air compressor load based on a feed-back control amount during an idling operation, and making various types of control such as engine speed control based on the detected load. CONSTITUTION:In ECU 15 inputted with a cooling water temperature signal, a throttle valve opening signal and a speed sensor output signal during the operation of an engine 11, idling speed feedback control is made to execute, when water temperature is equal to or above the predetermined value (about 70 deg.C), the engine 11 is idling with a throttle valve 18 closed and a vehicle speed drops to or below the predetermined value (about 2 km/h). Namely, an idling speed control valve 21 is so regulated that an engine speed becomes the predetermined idling target speed. Also, feedback control amounts respectively when an air compressor 14 is turned on and off, are memorized and a load on the air compressor 14 is detected on based on a difference between both amounts for use in controlling an engine speed.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides an air conditioning system installed in a vehicle in which an air compressor is driven by an engine. This invention relates to a detection device.

[Prior Art] In an air conditioner mounted on a vehicle such as an automobile, the air compressor is usually directly driven by the engine mounted on the vehicle. Therefore, such control of the air compressor is carried out in conjunction with engine control.
As shown in Publication No. 0221, it has been considered to detect the load of a compressor of a vehicle air conditioner based on its pressure, and to switch between air compressor control and engine control based on the detected load information. .

However, when detecting compressor load from pressure, it is necessary to set a pressure sensor for the compressor and configure the detection signal from this pressure sensor to be input to the control device of the air compressor or engine. becomes complicated and causes cost increases.

When an air compressor is driven by an engine, it is necessary to control the air compressor according to the operating conditions of the engine, and when the air compressor is connected to the engine, the operating conditions of the engine must be controlled according to the air compressor load. need to be controlled.

For example, in the engine idle speed control device disclosed in Japanese Utility Model Application Publication No. 57-18767, for example, 500
It has been proposed to disconnect the engine from the air compressor at low rotational speeds below rpm to prevent stalling.

In a device that turns off the compressor when the engine speed is below a predetermined speed, when the load on the compressor is extremely large, the deceleration of the engine speed becomes large, causing the compressor to turn off, for example. 50
Even if the off-control was performed at 0 rpm, there was a problem in that stalling could not be prevented.

[Problems to be Solved by the Invention] This invention has been made in view of the above points, and it is possible to perform load control corresponding to engine conditions without installing a detection mechanism such as a pressure sensor in the compressor. It is an object of the present invention to provide a vehicle air conditioning load detection device as described above.

[Means for Solving the Problems] In the vehicle air conditioning load detection device according to the present invention,
When an idle speed control control valve set in a passage bypassing a throttle valve of an engine to which an air compressor is connected is feedback-controlled in an idle operating state, the control amount for each of the on state and off state of the air compressor is controlled. The system detects and stores the difference in the feedback control amount, and detects the load state of the air compressor based on the difference in the feedback control amount when the air compressor is on and off.

[Operations] The vehicle air conditioning load detection device configured in this manner does not require any special configuration such as setting a pressure sensor on the compressor; The load amount of the air conditioner can be detected based on the difference in feedback control amount of the engine in the OFF state separated from the compressor. Therefore, the influence due to differences in the engine to which the air conditioner is connected, as well as the influence due to changes over time, etc., are reliably eliminated, and a more accurate air compressor load can be detected.

[Embodiments of the invention] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows its configuration, in which a belt 13 is attached to an output rotating shaft 12 of an engine 11 mounted on a vehicle such as an automobile.
The air compressor 14 of the '11 device mounted on this vehicle is connected via the engine 11, so that the air compressor 14 is driven by the engine 11. In this case, an electronic control circuit (ECU) configured by a microcomputer, etc., is set for engine control, etc.
) 15, the connection state between the engine 11 and the air compressor 14 is controlled on and off by, for example, a clutch mechanism (not shown).

Intake air for the engine 11 is taken in from the outside through an intake pipe 16, and this intake pipe 16 is equipped with an air flow meter 17 for measuring the amount of intake air, a throttle valve 18 for controlling the amount of intake air, etc. ing. Further, the injector 19 that supplies fuel to the engine 11 is
The fuel is controlled by the electronic control circuit 15, and an amount of fuel corresponding to the result calculated by the electronic control circuit 15 is supplied to each cylinder of the engine 11.

A bypass passage 20 is formed in the intake pipe 16 so as to bypass the throttle valve 18 portion. This bypass passage 20 is provided with an idle speed control valve 21 that controls the idle speed of the engine 11 during idle operation with the throttle valve 18 closed. This valve 21 is controlled by an electronic control circuit 15, and is configured to control the intake air supplied to the engine 11 via the bypass passage 20 so that the engine 11 is controlled to operate at a predetermined idle speed in an idling state. It comes to control the amount of air.

In addition, the intake system including the intake pipe 16 is provided with an intake temperature sensor 22 that measures the temperature of intake air, and the engine 11 is provided with a water temperature sensor 23 that measures the temperature of cooling water. The detection signal from
The signal is supplied to the electronic control circuit 15. Further, a rotation sensor 24 is provided on the rotation shaft 12 of the engine 11, and an engine rotation speed signal NE detected by the rotation sensor 243 is supplied to the electronic control circuit 15.

The electronic control circuit 15 is further supplied with an air conditioner switch (SW) signal from an air conditioner switch (not shown), which controls on/off of the vehicle air conditioner, and a throttle valve opening signal from the throttle valve 18. .

The electronic control circuit 15 responds to the intake air amount signal from the air flow meter 17 and the rotational speed signal NE of the engine 11.
The injector 19 is driven to inject a predetermined amount of fuel into the engine 1.
Supply to 1. Further, this electronic control circuit controls on/off a clutch mechanism that connects the air compressor 14 and the engine 11 in response to an on/off signal from an air conditioner switch (not shown).
Controls the driving state of on and off.

Here, in an idling operating state in which the throttle valve 18 is closed, the idle speed control valve 21 set in the bypass passage 20 performs feedback control to set the rotation speed of the engine 11 to the target rotation speed.

Figure 2 shows the flow of this feedback control.
In step 200, the cooling water temperature of the engine 11 is detected based on the detection signal from the water temperature sensor 23, and it is determined whether the detected water temperature is a predetermined temperature, for example, 70° C. or higher. When the detected water temperature is 70°C or lower, this process is immediately terminated, and when the water temperature is determined to be 70°C or higher, the process proceeds to the next step 201, where the throttle valve 18 is adjusted based on the opening signal of the throttle valve 18. Determine whether or not it is in an idle state.

When it is determined that the throttle valve 18 is not in a fully closed state and is not in an idling state, the process is terminated, and when it is determined that the throttle valve I8 is fully closed and in an idling state,
Proceeding to step 202, the vehicle speed detected based on the detection signal from the sensor that detects the wheel rotation speed of the vehicle body is determined.
It is determined whether or not it exceeds 2 KIl/h. Vehicle speed is 2
If it is determined that the vehicle speed is below Km/h, the process proceeds to step 203 to execute feedback control and reduce the vehicle speed to 2 Km/h.
In the above state, this process is ended without transitioning to feedback #JgrJ.

That is, when the water temperature is 70° C. or higher, the throttle valve 18 is closed and the vehicle is in an idling state, and the vehicle speed is 2 Ka+/h or less, the feedback control is started. In this feedback control state, the idle speed control valve 21 is controlled so that the rotation speed of the engine 11 is set to a predetermined target idle rotation speed.

FIG. 3 shows a routine for detecting the load on the air compressor 14 in a device that is feedback-controlled in this manner. In step 300, it is determined whether feedback control by the idle speed control valve 21 is being executed or not. Determine. If the feedback control is not being executed, this process is immediately terminated. If it is determined that the feedback control is being executed, the process proceeds to step 301 to check whether the air conditioner is on (the air compressor 14 is connected to the engine 11). If it is determined that the air compressor 14 is on, the process proceeds to step 302, and if it is determined that the air compressor 14 is disconnected from the engine 11, the process proceeds to step 303.

In step 302 when the air compressor 14 is connected to the engine 11, the control amount of the idle speed control valve 21 is set to DACON, and in step 303 when the air compressor 14 is disconnected from the engine 11, the control amount of the idle speed control valve 21 is set to DACON. Set the amount to DA COFF and store each.

In this way, in steps 302 and 303, the control f
Once f1DAcON and D A COFF have been stored, in step 304, the difference DAC between the control amount 1DAcON of the air compressor 14 in the on state and the control amount D A COFF in the off state is calculated and stored. . Then, this air conditioner load detection processing routine is ended.

FIG. 4 shows the difference DAC between the control amount of the idle speed control valve 21 when the air compressor 14 is connected to the engine 11 and the control amount when the air compressor 14 is disconnected from the engine 11, obtained in this way. , which shows the relationship with the air conditioner load, and there is a linear relationship between the two.

Furthermore, if there is a time lag between when the air compressor 14 is turned on and when the air compressor 14 is turned on and off when the control quantities DACON and DA COFF are detected and measured, respectively, the control quantities of the idle speed control valve 21 are In addition to the load on the air compressor 14, fluctuations due to changes in the intake air temperature to the engine 11 are included. In such a case, when detecting the control amount of the idle speed control valve 21, the control amount is corrected according to the intake temperature detected by the intake temperature sensor 22 according to the relationship shown in FIG.
Stored as DA CON and DA COFF. The control amount of the idle speed control valve 21 is a value corrected to correspond to the same intake air temperature value, and this correction allows the control amount purely for the load of the air compressor 14 to be detected. Become.

Next, control using the load of the air compressor 14 detected in this way will be explained.

Conventionally, in an engine connected to an air compressor, the engine rotates at a low speed (for example, 500 rpm), as shown in Japanese Utility Model Application Publication No. 57-18767
m) In the following conditions, it is considered to disconnect the engine and compressor to prevent the stall from occurring. When such control is executed, the deceleration of the engine speed is large when the load on the compressor is extremely large, and the compressor is reduced to an engine speed of 500 rpl.
Even if it is turned off at l, there is a problem that it is difficult to reliably prevent the stall from occurring.

In order to prevent this stall from occurring, the engine speed at which the compressor is turned off is set to 500 rpm.
If the engine speed is increased from 700 rpm to 700 rpm, for example, as shown in Figure 6, stalls can be prevented when the compressor load is large, but the difference from the normal engine idle speed will become smaller and the engine stall will be less likely to occur. Even in the case of a slight drop in engine speed, which is not a cause for concern, the compressor is turned off. Therefore, this is not a pleasant experience and may result in poor cooling.

However, as shown in the embodiment, the difference in load corresponding to the state of the compressor 14 of the vehicle air conditioner is detected,
If the rotational speed of the engine 11 where the engine 11 and the air compressor 14 are coupled is selected in accordance with the detected load as shown in FIG. Controlled off. Therefore, the control that turns off the compressor 14, which is undesirable for the user's experience, can be suppressed to the necessary minimum.

In addition, this detected air compressor load can be effectively used as a parameter for transmission control as well as engine control, and is used not only for engine control that corresponds to the control of in-vehicle air conditioners, but also for other driving controls. It can also be used as appropriate.

[Effects of the Invention] As described above, according to the vehicle air conditioning load detection device according to the present invention, this detection is performed based on the feedback control amount during idling operation without setting a special detection mechanism in the air compressor or the like. Air compressor load can now be detected. Based on this detected load, various controls such as engine rotation speed control are executed.

In particular, since the air compressor load is detected based on the difference in the feedback control amount when the air compressor is on and off, it is possible to detect variable factors other than the air compressor, such as engine intake air temperature, intake air amount, etc. over time. The effects of change are effectively removed.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating an air conditioning load detection device according to an embodiment of the present invention, FIG. 2 is a flowchart illustrating the flow of processing for executing engine feedback control in this embodiment, and FIG. Similarly, a flowchart explaining the process of detecting the control amount of the idle speed control valve, FIG. 4 is a diagram showing the relationship between the detected control amount and the air compressor load, and FIG. 5 is a diagram showing the correction amount for the intake air temperature. FIG. 6 is a diagram illustrating the relationship between the on/off control of the air compressor and the changing state of the engine speed, and FIG. 7 is a diagram illustrating the relationship between the detected load amount and the engine speed. 11...Engine, 14...Air compressor, 1
5... Electronic control circuit, 18... Intake pipe, 18...
Throttle valve, 19... Injector, 20...
- Bypass passage, 21...idle speed control valve.

Claims (1)

[Scope of Claims] In an air conditioner installed in a vehicle in which an air compressor of an air conditioner is coupled to a vehicle engine, an idle speed control set in a bypass passage that bypasses a throttle valve portion of an intake air passage of the engine. a control valve for the engine, and feedback control means for detecting the operating state of the engine to control the fuel injection amount of the engine, and for feedback controlling the control valve in an idling operating state with the throttle valve closed; a first storage means for storing the feedback control amount when the air compressor is turned off in a feedback control state where the rotation speed is set to the target rotation speed by the feedback control means; , a second storage means for storing the feedback control amount when the air compressor is turned on; and a second storage means stored in each of the first and second storage means.
and means for calculating a difference in feedback control amount when the air compressor is off and on, and the load amount of the air compressor is detected based on the difference in the feedback control amount obtained by the means. A vehicle air conditioning load detection device characterized by: