JPS6025812A - Air conditioner for vehicle - Google Patents

Abstract

PURPOSE:To enable to reduce load variation of an engine, by a method wherein a compression capacity varying device is driven for a period of predetermined time at the time of generation of an actuating signal through a temperature detector, and signals for clutch operation and variable manual driving are made to generate for a predetermined period of time at the time of completion of operation. CONSTITUTION:When a blow-off cool air temperature becomes more than a set value, an output of a temperature detecting circuit 8 is turned into ''H'', a solenoid clutch 3 is turned ON through a solenoid clutch circuit 9 and a compressor 2 provided with a compression capacity varying device is driven. In this instance, a compression capacity varying device 6 is operated through a driving circuit 10 during an operating period of time of a timer circuit 11, compression capacity is kept small for a predetermined period of time and then the compressor 2 is operated at a compression ratio corresponding to a cooling load. Then when the blow-off temperature is lowered and output of the temperature detecting circuit 8 is turned into ''L'', the compressor 2 is kept operated during a time limit of a timer circuit 12 by turning the solenoid clutch 3 ON and suspended by making it into a small compression capacity through the driving circuit 10 and the compression capacity varying device 6. With this construction, a load variation of an engine can be controlled by making the compression capacity small at the time of intermittence of the compressor.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle air conditioner, and more particularly to an air conditioner in which a compressor is driven by a motor of the vehicle.

In such air conditioners, a temperature detector detects the temperature at the evaporator, cold air outlet, or inside the vehicle of the refrigerant circuit, and when the detected temperature is above a predetermined temperature, an operation signal is generated and the motor output is transmitted to the compressor. The compressor is operated by using the clutches that operate the compressor one after the other. In such an air conditioner, each time the detected temperature rises or falls below a predetermined value.

The clutch is repeatedly engaged and disengaged, and the load on the prime mover changes rapidly each time, resulting in sudden changes in the running condition of the vehicle, making the ride uncomfortable.

In order to solve these drawbacks of vehicle air conditioners, the present invention reduces the load on the prime mover by the compressor when the clutch is engaged and immediately before the clutch is disengaged, so that large load fluctuations are not temporarily applied to the prime mover. It is an object of the present invention to provide a vehicle air conditioning system.

The present invention drives a compressor of an air conditioner via a clutch using the output of a vehicle's prime mover, and generates an operation signal to drive the clutch when the temperature detected by a temperature detector is higher than a predetermined value. In the vehicle air conditioner which is operated, a compressor equipped with variable compression volume means is used as the compressor, and when the operation signal is generated, a signal is generated to drive the variable compression volume means for a certain period of time, On the other hand, the air conditioner is equipped with a control circuit that generates a clutch operation signal and a signal for driving the compression volume variable means for a certain period of time at the end of the operation signal, thereby reducing the compression volume when the compressor is turned on and off. be.

According to the present invention, when the temperature rises and exceeds a predetermined value, the clutch operates and the compressor starts.

During the first certain period of time, the compressed volume of the compressor is small.

will be carried out in stages. Meanwhile, the temperature is dropping.

When the temperature reaches the point where the compressor stops operating, the clutch is not immediately disconnected, and the compressor is kept in operation for a short period of time, during which time the compression volume of the compressor is reduced, and then the clutch is disconnected and the compressor is disconnected. Since the compressor is stopped, the load on the prime mover is reduced in stages even when the compressor is stopped. Therefore,
Since no sudden load changes are applied to the prime mover when the compressor is started or stopped, stable running conditions can be achieved even when an air conditioner is used.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In Figure 1 (a), a cold air generation section 1 including a refrigerant circuit and a cold air blowing fan (shown as a block, details omitted)
A refrigerant compressor 2 connected to the refrigerant circuit is equipped with an electromagnetic clutch 6 and a pulley 4. The pulley 4 is connected by a belt 5 to an output IQb of a motor 9 of a vehicle, such as an automobile engine (not shown), and is rotated by the engine output. The Sunda compressor 2 is of a variable compression volume type, and examples of this type of compressor include the earlier patent application filed in 1983-
There is one disclosed in No. 33646 (Japanese Unexamined Patent Publication No. 57-148089). Compression volume variable means (shown as a lunoid valve in the above-mentioned prior application) 6 is provided in the compressor 2, and is shown by a nine-dot line block in FIG.

The lead wires E and F of the electromagnetic clutch 6 and the lead wires C and D of the compression volume variable means B are E and F in the control circuit 1 shown in FIG. 1(b). : Go to C and D.

They are connected to each other and operate under the control described below.

For example, the thermistor 7 can be used as a temperature detector for an air conditioner.
It is installed at the cold air outlet, and its leads 1-mA and B are connected to A and B in the control circuit shown in FIG. 1 (1)). Of course, the temperature detector 7 may be provided in the evaporator part of the refrigerant circuit or inside the vehicle. In any case, when the detected temperature exceeds a predetermined value, the compressor is operated, and when the detected temperature falls below the predetermined value, the compressor is stopped, thereby air conditioning the interior of the vehicle.

Referring to FIG. 1(b), the control circuit shown in FIG. 2 includes a temperature detection circuit 8 which generates a compressor operation signal when the temperature detected by the thermistor 7 is equal to or higher than a predetermined value.

The electromagnetic clutch 6 operates when this compressor operation signal is present.
- and an electromagnetic clutch drive circuit 9 that drives.

A variable compression volume means drive circuit 10 that drives the variable compression volume means 6, and a first circuit that operates when a compressor operation signal is output from the temperature detection circuit 8 and generates a variable compression volume means operation signal for a predetermined period of time. and a second timer circuit 12 that operates when the output of the compressor operation signal from the temperature detection circuit 8 stops and generates a compression volume variable means operation signal for a predetermined period of time. . Timer circuit 11
The outputs of and 12 are applied to the variable compression volume means driving circuit 10, whereby the variable compression volume means 6 is operated. Second
The output of the timer circuit 12 is simultaneously applied to the electromagnetic clutch drive circuit 9 to maintain the electromagnetic clutch drive circuit 9 in an operating state in place of the compressor operation signal from the temperature detection circuit 8.

Next, specific examples of each circuit will be explained with reference to FIG. 1(b).

The temperature detection circuit 8 includes, as in the conventional case, a bridge circuit composed of the thermistor 7 and the resistor RI + R2 + R3, a connection point p between the thermistor 7 and the resistor R1, and a resistor R2.
and a comparator 81 consisting of an operational amplifier whose inputs are connected to the connection point P2 of R1 and R1 (the operating temperature is set to have hysteresis by a resistor Rf). In the illustrated configuration, when the temperature of the thermistor 7 rises and the voltage of Pl exceeds the voltage of R2, the output voltage of the comparator 81 becomes H level and a compressor operation signal is generated.

When the temperature of thermistor 7 is low and the voltage of p+ is lower than the voltage of R2, the output of comparator 81 is kept at L level. Note that the resistor R3 is a variable resistor and is used to adjust the compressor operating temperature.

The electromagnetic clutch drive circuit 9 includes a transistor Tr that is turned on when a compressor operation signal from the temperature detection circuit 8 is applied to it via an OR circuit 91, a +-transistor Tr, and a relay connected between the power source (2). The operation closing contact of the relay 92 is connected between the power supply (1) and the electromagnetic clutch 6.

Therefore, when the compressor operation signal is output from the temperature detection circuit 8, the transistor Tr is conductive and the relay 92 is in the operating state.

The electromagnetic clutch 6 operates, and the compressor 1 is driven by the engine output transmitted to the pulley 4. When there is no compressor operation signal, the transistor Tr is off, so the compressor is not driven.

As described above, when the compressor operation signal of the temperature detection circuit 8 disappears, the OR circuit 91 uses the output of the second timer circuit 12 in order to keep the electromagnetic clutch 3 in the operating state for a predetermined period of time. It is used to apply a signal to the base of the transistor Tr.

The drive circuit 7 of the compression volume variable means B is an OR circuit 1 which makes the outputs of the first and second timer circuits 11 and 12 human-powered.
01 and a transistor Tr2 to which the output of the OR circuit 101 is applied as a base, and a compression volume variable means 6 is connected between the transistor Tr2 and the power supply (2). Therefore, when a compression volume variable means driving signal is output from either of the first and second timer circuits 11 and 12.

Since the transistor Tr7 becomes conductive and power is supplied to the compression volume variable means 6, the compression volume M'Jt of the compressor 2 becomes smaller.

The first timer circuit 11 includes a charging/discharging circuit including a diode D1, a resistor R4, and a capacitor c1, a comparator 111 including an operational amplifier, and an AND gate 112. The charging circuit is connected to the output line of the temperature detection circuit 8, and when the voltage V on the output line is I (level), capacitor c1 is charged via resistor R4, and when it is L level, diode D is charged.
It is rapidly discharged through 1. One terminal of the comparator 111 is open. Therefore, the charging voltage of capacitor C5 is the reference voltage V. While the voltage is lower, the output of the comparator 111 is at H level, and the charging voltage of the capacitor is V. In this case, the output of the comparator 111 is at L level.

Since the output of the comparator 111 and the output of the temperature detection circuit 8 are connected to the AND gate 112, the temperature detection circuit 8
An H level signal is generated at the output of the AND circuit 112 only when both the output of the AND circuit 111 and the output of the comparator 111 are at the H level. Therefore, when the output of the temperature detection circuit 8 changes from L level to H level, that is, while the compressor operation signal appears, R
With a time constant determined by 1 and C1, the capacitor C is set to the reference voltage V.
An H level signal is generated from the ANDKET 112 for the charging time up to o (r+), and this signal is sent to the OR circuit 101 of the variable compression volume means drive circuit 1o as the variable compression volume means operation signal. applied.

The second timer circuit is similarly connected to the output of the temperature detection circuit 8, and has a diode D2. It has a charging/discharging circuit consisting of a resistor R7 and a capacitor C2.

Capacitor C2 is rapidly charged via diode D2 when the output of temperature detection circuit 8 is at H level, and discharged via resistor R7 when it is at L level. The charging voltage of the capacitor C2 is inputted to the 11 terminal of the comparator 121, and the above-mentioned reference voltage is inputted to one terminal of the comparator 121. Therefore, the output of the comparator 121 becomes H level when the voltage of the capacitor C2 is higher than the reference voltage vo, and the voltage of the capacitor C2 becomes the reference voltage V. It becomes L level in the following cases.

The output of the comparator 121 is applied to one input of the AND gate 122, and the other input of the AND gate 1-122 is
Since the output of the temperature detection circuit 8 is inverted by the inverter 126 and added, the output of the Antoge 1-122 is
An H level signal is output only when both the output of comparator 121 and the output of inverter 126 are at H level. Therefore, when the output of the temperature detection circuit changes from II level to L level.

That is, when the compressor operating signal disappears, capacitor C2
The voltage becomes the reference voltage ■ with the time constant of R7XC2. The output of the AND gate 122 becomes H level for the discharge time (this time is defined as T2) until the voltage is discharged, and this H level signal is sent to the OR circuit 101 of the compression volume variable means drive circuit 10 as the compression volume variable means operation signal. added to the other input. Further, this H level signal is sent to the OR circuit 91 of the electromagnetic clutch drive circuit 9 as an electromagnetic clutch operation signal.
is added to the other input.

The control operation will be explained below with reference to the time chart shown in FIG.

When the cold air outlet air temperature rises from a low temperature as shown in FIG. The output changes from L level to H level as shown in FIG. 2(b). That is, a compressor operation signal is output. Therefore, the electromagnetic clutch drive circuit 9 operates to operate the electromagnetic clutch 6 as shown in FIG. 2(C).
This causes the compressor to operate.

When the compressor operation signal is output, the first timer circuit 11
operates and generates a compression volume variable means driving signal for a time T1 as shown in FIG. 2(d).

As a result, the variable compression volume means drive circuit 10 operates, and the variable compression volume means 6 is operated to keep the compression volume of the compressor 2 small for 9 hours T1. The period in which the compressor is operated with a small compression volume is indicated by the shaded area A in FIG. 2(c).

The compressor 2 is operated, and as shown in FIG. 2(a),
When the cold air outlet temperature begins to decrease and reaches the temperature Te2 at 2 time t2, the thermistor detection temperature reaches the compressor stop temperature, as shown in FIG. 2(b).

The output of the temperature detection circuit 8 changes from the TI level to the L level. That is, the compressor operation signal disappears. However,
At this time, the second timer circuit 12 outputs a signal for a time T2 as shown in FIG. 2(e), and this signal is given to the OR circuit 91 of the electromagnetic clutch drive circuit 9.
Since the electromagnetic clutch 6 still operates as shown in FIG. 2(c), the compressor 2 continues to operate. At this time.

The output of the second timer circuit 12 is simultaneously applied as a compression volume variable means drive signal to the compression volume variable means 1 drive circuit 10, so that the compressor 2 can be operated with a small compression volume. .

That is, even if the compressor operation signal from the temperature detection circuit 8 disappears, the operation of the compressor 2 continues with a small compressed volume (this state is shown by line B in FIG. 2(c)). , T
After two hours have passed, the electromagnetic clutch 6 stops operating and the compressor 2 stops operating.

In this way, the cold air blowout temperature begins to rise again, reaching T e , and the above-described operation is repeated.

Thus, according to this embodiment, the compressor 2 is operated with a small compression volume for 2 hours 'I'1 at its start-up, and then with a rated compression volume, -1
: When the compressor 2 is stopped, the compressor 2 is stopped after passing through the operating state of a small compression volume, so there is an advantage that the load of the engine, which is the driving force source of the compressor 2, does not undergo sudden fluctuations.

In the above embodiment, the compressed volume of the compressor 2 is reduced only when the compressor is started or stopped.2 For example, when the cooling load is small, the compressed volume is reduced and the air conditioner is operated. You may also do this. An example of a control circuit in such a case is shown in FIG.

The control circuit shown in FIG. 6 includes a cooling load detection circuit 13 that detects whether the cooling load at that time is small or small, and outputs a compression volume variable means operation signal when it is small.

This is an addition to the control circuit shown in FIG. Therefore, the sixth
In the figure, parts similar to those in the circuit of FIG. 1 are indicated by blocks with the same reference numerals, and only the changed part is shown in detail #1.

That is, among the resistors forming the bridge in the temperature detection circuit,
The resistor R2 in the circuit of Figure 1 is replaced by two resistors R, 8, R
, which makes the connection point P between resistors R8 and RQ
3 is taken out and compared with the point voltage p as described later, the temperature detected by the thermistor is a temperature higher than the air conditioning operation setting temperature adjusted by variable resistor R3 by a predetermined value;
In other words, it is possible to detect that the cooling load is high.

On the other hand, so that the compression volume variable means 6 can also be operated by the compression volume variable means drive signal from the cooling load detection circuit 16, the OR circuit of the compression volume variable means and the prefecture circuit 10 is connected to the three-person chaor circuit 101. ' is used.

The cooling load is still small, and the cooling load detection circuit 16 outputs a compression volume variable means operation signal.

When the compressor operation signal from the temperature detection circuit 8 disappears while the compressor is operating with a small compression volume.

Since it is not necessary to continue the compressor operation for 12 hours with the output of the second timer circuit 12, the output of the second timer circuit 12 is controlled by a signal obtained by inverting the output of the cooling load detection circuit 15 with the inverter 14. -Electromagnetic Kushinochi drive circuit through 115? has been input to.

Therefore, the operation of the control circuit of FIG. 6 is exactly the same as that of the circuit of FIG. 1 when there is no compression volume variable means operation signal in the output of the cooling load detection circuit 16, and when there is, the operation signal of the control circuit of the timer circuit 11. 12, the compressor operates under the control of the output of the temperature detection circuit 8 with a small compression volume.Next, the cooling load detection circuit 16 will be described.

Generally, if the cooling load is high, the compressor operating time is long, and if the cooling load is low, the operating time of the compressor is short. Therefore, whether the cooling load is high or low,
It is expressed by the ratio of the operating time to the sum of the operating time and the stop time of the compressor (this is expressed as the operating rate and 11A and K).

Therefore, in order to determine the operating rate of the compressor of the air conditioner that is actually in operation, the cooling load detection circuit 16 is set to 1. Temperature detection circuit 8
diode D to the output V1.

A capacitor C3 is connected through a parallel circuit of a first series circuit consisting of a resistor "ltl", a diode D, and a second series circuit consisting of one resistor, and when +vI is at H level, a capacitor C3 is connected through the first series circuit. A charging/discharging circuit is provided which discharges the charge of the capacitor C1 through the second series circuit when the capacitor C1 is charged and the voltage 1 is at the L level.

By the way, the time when Vl is at II level is the operating time of the compressor.

Since the time at the level L in Table L is the stop time, the peak value of the terminal voltage c3 of the capacitor C3 corresponds to the momentary operating rate K of the compressor.

Therefore, a predetermined operating rate K is used to determine whether or not the compressor is operated with a small compression volume. ′low pressure vR corresponding to resistance R,
,,,R,3, and the comparator 162 compares VO2 and vR. Naori R is applied to the ten-power terminal, and VO2 is applied to one input terminal.

Here, if the voltage V c 3 exhibits a change as shown in FIG. 4(,), an output v132 as shown in FIG. 4(b) is obtained at the output terminal of the comparator 132. That is,
VO2) +V+32H in the range of VR (i.e. K>K.)
In other cases, it becomes I (level).

The output voltage 9,2 of this comparator 162 is connected to a resistor R1.

R+'(R14>> R15) l diode D5
．． Smoothing is performed using a smoothing circuit consisting of capacitor C4, and the smoothing/
h voltage V c s is further input to the 4-human power terminal of the comparator 163 . In addition, VO4 is Ie14 >>
As shown in FIG. 3(c), the rising edge is slower than the falling edge.

The voltage V c 4 is the actual operating rate K (is the limit operating rate K set by the reference voltage VR. This is because it represents the integral value of the higher time subtracted from the lower time.

The longer the time for K (Ko), the higher the vC41d, which indicates that the cooling load is very small.

Therefore, in order to know that the difference between the time when K<Ko and the time when :)Ko becomes a preselected predetermined time, a voltage V corresponding to the predetermined time is created using resistors R16 + R17 and compared. Vc
It is compared with 4. Therefore, the output V133 of the comparator 133 has Vc4.

In this case, the H level is output (FIG. 4(d)).

That is, the operating rate K of the compressor is the critical operating rate K. When the lower time continues, the cooling load is assumed to be small, and a compression volume variable means operation signal is output.

As a result, the compression volume variable means 6 operates, and the compressor operates with a small compression volume.

Note that when the output of the comparator 133 becomes H level.

Since it is applied to the input terminal of the comparator 162 through the diode D6, the reference voltage level 2 increases (see FIG. 6(a)), and as a result, even if the cooling load becomes high, V, 33 remains at 1.
It is maintained at level 1.

When the cooling load increases above a certain value, it is necessary to increase the compression capacity of the compressor to increase the cooling capacity. I mentioned this earlier. A comparator 131 compares the voltages at points 21 and 21 in the bridge circuit of the temperature detection circuit 8, and when the thermistor detected temperature reaches a predetermined temperature higher than the compressor operating temperature, the output of the comparator 131 is set to L level. As a result, an L level is applied to the input terminal of the comparator 162 via the diode D7, lowering the reference voltage. Therefore, the time at L level of v13□ becomes longer, and the output of comparator 136 also becomes L level. In this way, variable compression volume compression is deactivated, and thereafter the compressor is operated with a large compression volume.

Thereafter, similar operations are repeated.

As mentioned above, according to the circuit shown in Figure 4, the compressor is always driven with a compression volume commensurate with the cooling load, and when the compressor is operated with a large compression volume, there is a temporary Since the engine goes through an operating state with a small compression volume, the engine load changes in stages, and has the advantage that large load fluctuations cannot be applied all at once.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, (a) is a system diagram showing the air conditioner section, (b) is a control system diagram thereof, and FIG.
Figure (a) shows an example of temperature change at the cold air outlet, and (b)
~(e) are time charts of signals of various parts in the circuit of FIG. 1(b), FIG. 5 is a control circuit diagram of another embodiment of the present invention, and FIGS. 4(a) to (d) 4 is a time chart of various signals in the circuit of FIG. 4. FIG. DESCRIPTION OF SYMBOLS 1... Cold air generation part, 2... Compression volume variable compression (shallow). 6... Electromagnetic clutch, 6... Compression volume variable means. 7... Thermistor, 8... Temperature detection circuit. 9... Electromagnetic clutch drive circuit. 10... Compression volume variable means drive circuit.

Claims (1)

[Claims] 1. The compressor of the air conditioner is driven by the output of the motor of the vehicle via a clutch. In a vehicle air conditioner that generates an operation signal to operate the clutch when the temperature detected by the temperature detector is equal to or higher than a predetermined value, the compressor is equipped with a compression volume variable means as the compressor, When the operation signal is generated, a signal is generated to drive the compression volume variable means for a certain period of time, and at the end of the operation signal, a clutch operation signal is generated.
It is equipped with a control circuit that generates a signal for driving the compression volume variable means (2) for a certain period of time.