JPH0490921A - Vehicle air conditioner using variable capacity type compressor - Google Patents

Abstract

PURPOSE:To control at a proper value the rotation speed of an engine and a compressor, by conducting the forecast calculation of the drive torque of the compressor at the time of engine idling on the basis of an outer air temperature detection signal, and at the same time transmitting a drive torque signal toward an engine controller. CONSTITUTION:A temperature sensor 6 is furnished at the front of a condenser 5, and detects an outer air temperature, and feeds it to a drive torque calculation amplifier 7. The amplifier 7 is supplied with a drive torque calculation expression made out on the basis of the previously set relationship diagram of outer air temperature and idling time compressor drive torque, and conducts the forecast calculation of the drive torque of a compressor 1 at the time of idling, and feeds a torque signal to an engine ECU 8. Thus, controlling almost fixedly a vehicle engine idling speed at a variable capacity system becomes possible by conducting at all times the forecast calculation of compressor drive torque at the time of idling and feeding the information to the engine ECU 8.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vehicle air conditioner using a variable displacement compressor, and in particular, the present invention relates to a vehicle air conditioner using a variable displacement compressor. The present invention relates to means for predicting the driving torque required by the compressor.

[Conventional technology]

In the conventional technology, as one of the methods for controlling the idle speed of a vehicle engine, the amount of engine intake air when idling before driving is stored as a learned value, and when the next idling state is reached, the amount of engine intake air is stored as a learned value. The idle speed is controlled to be constant by supplying an intake air amount based on a learned value. In this case, in order to prevent the idle speed from decreasing when the air conditioner is activated, the amount of air supplied to the engine is increased by a certain amount when the compressor is activated. It's normal.

[Problem to be solved by the invention]

In a system that uses a variable capacity compressor in a vehicle air conditioner, if the heat load changes significantly before and after driving, the refrigerant discharge capacity of the compressor will change significantly, and the driving torque will also change significantly. However, in systems that cannot control in response to changes in drive torque, such as the conventional idle speed control method, fluctuations (dispersions) in the idle speed, such as drops in rotation speed and racing, may occur, and sometimes engine stalling may occur. There was also the risk of a riot.

Therefore, the present invention is a vehicle air conditioner (J:) using a variable displacement compressor, hereinafter abbreviated as a variable displacement system. )
Compressor drive torque prediction means that predicts the compressor drive torque at idle, sends the information to the electronic control unit (EC[J) that controls the engine, and controls the engine and compressor rotational speeds to appropriate values. This is what we are trying to provide.

[Means to solve the problem]

A vehicle air conditioner using the variable displacement compressor of the present invention includes:
an outside air temperature detection means for detecting outside air temperature and transmitting an outside air temperature signal in order to know the current heat load in the operating state;
Drive torque calculation means for predicting the drive torque of the compressor when the engine driving the compressor is idle based on the outside air temperature detection signal and transmitting a drive torque signal to a control device of the engine; It is characterized by having the following.

[For production]

The driving torque of a variable displacement compressor at idle is:
Our experiments have revealed that it has characteristics that are almost proportional to the outside temperature in all regions from the maximum capacity region to the variable capacity region.

In order to take advantage of this characteristic, the present invention has the configuration as described in the section of the means above, and can appropriately predict and calculate the driving torque of the variable displacement compressor when it is idling. By sending this information to the engine's ECU, it becomes possible to control the idle speed of the engine in the variable displacement system to be substantially constant.

〔Example〕

FIG. 1 shows one example in which the present invention is applied to a variable capacity system, in which a variable capacity compressor 1 is connected between an evaporator 2 and a condenser 5. This variable capacity compressor 1 is operated by being rotationally driven by a vehicle engine (not shown), and sucks refrigerant from an evaporator 2 in an amount corresponding to the heat load, compresses the sucked refrigerant, and compresses the refrigerant. It is discharged to the condenser 5 as compressed refrigerant.

FIG. 7 shows an example of the variable displacement compressor 1 used in the vehicle air conditioner of the present invention (VF Application No. 2-1).
No. 07513). In the same figure, 11 is the front cylinder, 12 is the rear cylinder, 13 is the front housing,
14 is a rear housing, and these are integrated by through bolts 15. Cylinder bores 16,
17 are drilled, each pair of cylinder bores 16.17
A common double-headed piston 18 is inserted so as to straddle the swash plate 1.
It is slidably engaged with the peripheral edge of 9.

Since the slider pin 22 inserted and guided through the axially elongated hole 21 of the input rotating shaft 20 passes through the center of the swash plate 19, a two-stop position for tilting around the pin 22 is formed. In addition, an arm pin 24 attached to an arm 23 integrated with the swash plate 19 is provided in a cam groove 2 inclined to the rotating shaft 20.
5, when the slider pin 22 moves in the axial direction, the arm pin 24 moves within the cam groove 25,
The inclination angle of the swash plate 19 changes, and the piston 18 moves into the cylinder bore 16,1? The stroke moving within the cylinder increases or decreases, thereby changing the discharge volumes of the first working chamber 26 and the second working chamber 27 within the cylinder bore.

In order to control the angle of inclination of the swash plate 19, the left end of the shaft portion 30 of the spool 29 is engaged with the center opening 28 at the right end of the rotating shaft 20. The spool 29 can slide axially within a control cylinder 31 formed in the rear housing 14 and forms a control pressure chamber 32 . 33 is a pressure control valve;
Although the detailed structure is not shown, the air conditioner's electronic control system M
(ECU) to selectively connect refrigerant at the suction pressure or discharge pressure of the refrigerant of the compressor 1 to the control pressure chamber 32, thereby increasing the control pressure in the control pressure chamber 32 from the discharge pressure to the suction pressure. , thereby changing the spool 2
9 is moved in the axial direction to control the inclination angle of the swash plate 19 and, therefore, the displacement of the compressor 1.

The first working chamber 26 and the second working chamber 27 can communicate with the first suction chamber 34 and the second suction chamber 35 through a suction valve, respectively, and can communicate with the first discharge chamber 34 through a discharge valve, respectively.
6 and the second discharge chamber 37 . Each suction chamber 34 and 35 both communicate with a central swash plate chamber 38, and each suction chamber 34 and 35 communicate with a central swash plate chamber 38.
4) to the evaporator 2 of the vehicle air conditioner. Each of the discharge chambers 36 and 37 is connected to the condenser 5 from the discharge port via a path not shown.

When the rotating shaft 20 is rotationally driven by the vehicle engine, the swash plate I9 also performs a rocking movement in addition to the same rotational movement. The component of the rocking motion causes the piston 18 to reciprocate in the axial direction, and the work of compressing the refrigerant in the magnitude corresponding to the stroke is performed in the two working chambers 26 and 27.

The pressure of the refrigerant in the control pressure chamber 32 supplied by the pressure control valve 33 by the ECU of the air conditioner is generated by the differential pressure between the suction pressure of the refrigerant in the second suction chamber 35 and the moment that tends to tilt the swash plate 19, and the compression work. The spool 29 moves in the axial direction to a position where it balances the moment generated by the movement of the swash plate 19 to raise it up, and as a result, the slider pin 22 moves in the axial direction together with the swash plate 19. The engagement changes the inclination angle of the swash plate 19 and changes the stroke of the piston 18, but in the variable displacement compressor 1 shown in FIG. Since the center of the swash plate 19 shifts to the right in the figure, effective compression work is no longer performed in the first working chamber 26, and compression work with a small discharge volume continues only in the second working chamber 27. Ru. This makes it possible to control the discharge volume over a wide range of high and low levels.

Corresponding to the features of the present invention, the temperature sensor 6 in the embodiment shown in FIG. send to This amplifier 7 has a relationship diagram between outside air temperature and compressor drive torque at idle as shown in Figure 2, which was determined by experiment in advance (the upper and lower straight lines shown as "actual torque" are at maximum load, respectively). This shows the compressor drive torque with respect to the outside air temperature at the minimum load, and the actual torque will be distributed between these two straight lines.) The drive torque calculation formula created based on According to the flowchart shown in FIG. 3, the driving torque of the compressor 1 at idle is estimated.

Furthermore, the amplifier 7 also has a function of sending the torque signal calculated in this way to the ECU Ill of the engine.

Therefore, when the air conditioner (A/C) switch is turned ON, the drive torque calculation amplifier 7 executes a program as shown in the flowchart of FIG. 3 from step 101, and in step 102 the temperature sensor 6 The outside air temperature t to be detected is read. In step 103, the expected torque T is calculated by multiplying the outside temperature t by a set constant (gradient of expected torque shown in FIG. 2) α and adding a constant β to this.
In 04, the engine's EC is used as a torque signal.
Send to U3. The program shown in FIG. 3 can be repeatedly executed at predetermined time intervals while the air conditioner is turned on, and when the outside temperature t changes, the expected torque T is also updated.

The embodiment shown in Fig. 1 has the above-described configuration and operation, so that it is possible to always predict the drive torque of the compressor during idling, and use this information to calculate the engine's E.
By sending it to the CU 8, it is possible to control the idle speed of the vehicle engine in a variable displacement system to be approximately constant.

Next, a second embodiment will be described in which the ability to control the idle speed is further improved. In order to reduce the width of the variation in idle speed, it is necessary to reduce the deviation between the expected torque and the actual torque. Since the air volume of the blower fan 3 that sends air to the fan 2 is used, the voltage applied to the motor that drives the blower fan 3 (referred to as blower voltage) is extracted as a signal indicating the air volume and is input to the amplifier 7. Furthermore, the amplifier 7 is provided with an expected torque calculation formula created based on the relationship diagram between outside temperature and expected torque using the blower voltage as a parameter as shown in FIG. To accurately predict and calculate driving torque during idling according to a flowchart.

That is, step 20 of the flowchart shown in FIG.
1, when the switch of the air conditioner is turned on, the process proceeds to step 202, where the outside air temperature t is read from the temperature sensor 6 into the drive torque calculation amplifier 7. In step 203, the blower voltage V is also read, and in step 204 it is compared with a predetermined voltage, for example 6V. Blower voltage V is 6V
If the voltage is higher than that, the process proceeds to step 205, where the predetermined voltage and
For example, it is compared with IOV. If the blower voltage V is greater than IOV, the process proceeds to step 206, in which the maximum one of the three predicted torque straight lines shown in FIG. 5 is selected, and the constant β2 is selected.
), calculate the expected torque T by calculating T=α・t+β2, and proceed to step 20.
7, it is sent as a torque signal to the engine's ECLI 8.

As a result of the determination in step 204, the blower voltage V is 6.
If it is smaller than V, the process proceeds to step 209 and selects the minimum one among the three predicted torque straight lines shown in FIG. 5 (constant β1 is adopted), and calculates T=α·t+β1.

Also, based on the determination in step 205, the blower voltage V
If is smaller than IOV, since 5<V<10, the process proceeds to step 211, and the constant β3 is selected to select the middle one among the three predicted torque straight lines shown in FIG. 5), T- Calculate α·t+β3.

In the embodiment shown in FIG. 4, the program of the amplifier 7 is somewhat complicated due to such a configuration, but the deviation between the actual torque and the expected torque is more than that in the embodiment shown in FIGS. 1 to 3. This makes it possible to accurately control the idle rotation speed to the target rotation speed.

In the above embodiment, the temperature sensor 6 for detecting the heat load is attached to the front of the condenser 5 to directly detect the outside air temperature. Even if the inlet air temperature of the evaporator 2 is detected, the same effect can be achieved by simply changing the equation for calculating the expected torque applied to the amplifier.

〔Effect of the invention〕

Vehicle air conditioners that use variable displacement compressors have excellent controllability of air conditioning capacity and can maintain the most comfortable interior of the vehicle, but on the other hand, the driving torque of the compressor fluctuates widely, so When the driving engine is idling, it is difficult to maintain the rotation speed constant, but according to the present invention, by providing a means for constantly predicting the driving torque required by the variable displacement compressor in the idling state, Even if the heat load of the air conditioner fluctuates, a substantially constant rotational speed close to the target value is obtained during idle, and the idle rotation is stable and there is no risk of engine stalling or runaway.

[Brief explanation of drawings]

Fig. 1 is a system diagram conceptually showing one embodiment of the present invention;
The figure shows a control map used in the embodiment shown in Fig. 1, Fig. 3 is a flowchart showing the same operating program, Fig. 4 is a system diagram conceptually showing another embodiment, and Fig. 5 is a control map used in the embodiment shown in Fig. 4. The control map used in the embodiment, FIG. 6 is a flowchart showing the operating program, and FIG. 7 is a vertical sectional view illustrating the specific structure of the variable displacement compressor. 1... Variable capacity compressor, 2... Evaporator, 3... Prower fan, 4
...Expansion valve, 5.Condenser, 6.Outside temperature sensor, 7.Drive torque calculation amplifier, 8.Engine ECU. 18... Piston, 19... Swash plate, 26.
27... Working chamber, 29... Spool, 32...
・Control pressure chamber. 1 Fig. 1...Variable capacity compressor 5...Condenser 6...Outside air temperature sensor 7...Drive torque calculation amplifier 8...Engine ECU Fig. 42...Evaporator 3 ...Blower fan 5...Condenser 6...Outside air temperature (kgm) Outside air temperature (℃)

Claims (1)

[Claims] a variable displacement compressor that can change the discharge capacity according to the heat load; an outside temperature detection means that detects outside air temperature as the heat load and transmits it as an outside temperature detection signal;
A driving torque calculating means is provided for predicting the driving torque of the compressor when the engine driving the compressor is idle based on the outside air temperature detection signal and transmitting the driving torque as a compressor driving torque signal. A vehicle air conditioner using a variable capacity compressor characterized by the following.