JPS59227521A - Air conditioner of vehicle - Google Patents

Abstract

PURPOSE:To provide efficient cooling according to engine rpm. by interrupting a compressor when the pressure in a refrigerating system exceeds a reference value, namely, a preset high pressure value of the refrigerating system which is reduced according to increase in engine rpm. CONSTITUTION:When a pressure sensor 10 detects a pressure of a refrigerating system, the sensor generates a detecting signal (e1) whose output level is increased according to increase in pressure P, and sends the signal via a noise filter 15 to a driving part 13 as a detecting signal (e1'). When an engine rpm. sensor 12, on the other hand, receives a revolution pulse from an ignition coil 11, the sensor 12 sends a detecting signal (e2), whose output level is reduced according to increase in revolution speed (r), to the driving part 13. When the driving part 13 compares the signals (e2) and (e1) with each other and finds that the detected pressure (e1') exceeds the reference value (e2), the part 13 cuts off the driving loop of a magnet clutch 7 to interrupt driving of a compressor 1. That is, the compressor may be interrupted when the pressure of the refrigerating system exceeds a high preset value and cooling operation may be performed efficiently according to engine rpm., whereby preventing insufficient cooling at the time of a low engine speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a vehicle air conditioner, and particularly to a vehicle air conditioner suitable for use as an air conditioner for a vehicle such as an automobile.

[Background of the invention]

Conventionally, as air conditioners for vehicles such as automobiles, a compressor is driven according to the engine speed to compress refrigerant, and the refrigeration cycle is repeated to sequentially supply the compressed refrigerant to the refrigeration system, so that the pressure in the refrigeration system is set to a high pressure. A system has been proposed in which the drive of the compressor is stopped when the value is exceeded.

As shown in Fig. 1, this conventional glazed air conditioner drives a compressor 1 according to the engine speed to fully compress the refrigerant, and then transfers the compressed refrigerant to a condenser 2, a liquid tank 3, and an expanded tank. When the pressure switch 6 detects that the pressure in the refrigeration system has exceeded the high pressure set value during a complete repetition of the refrigeration cycle in which the refrigeration system including the valve 4 and the evaporator 5 is sequentially supplied, the pressure switch 6 is actuated by a magnet. The power supply 8 to the clutch 7 is cut off, and the compressor 1
The drive of the motor is stopped. That is, in the refrigerator shown in FIG. 1, when the pressure in the refrigeration system exceeds the set pressure due to insufficient cooling of the condenser 2, the drive loop of the magnetic clutch 7 that is used to drive the compressor 1 is cut off. The compressor 1 is configured to stop driving and completely prevent the compressor 1 from receiving mechanical damage. The high pressure setting value of the refrigeration thread of the compressor 1, which stops in one progressive tray, is set based on FIG.

That is, if the horizontal axis is the rotational speed N' of the compressor 1 and the total pressure P of the refrigeration system is plotted on the vertical axis, the area Z on the sieve pressure side of the compressor inoperability limit line 2 is the area where the compressor is susceptible to mechanical damage. Represented as a region. Therefore, the compressor 1 can be protected by fully operating the ramie conditioner in a region on the lower pressure side than the allowable limit line t to which the safety factor is fully added. On the other hand, when the pressure of the refrigeration system exceeds the allowable limit line t,
The drive of the compressor 1 can be completely stopped by completely protecting the compressor 1.

However, as shown in FIG.
c was set n. Therefore, as shown in the area in Fig. 2, in the low fault 1 transition area, the pressure switch 6 operates at a pressure far lower than the allowable limit line t and the compressor 1 stops, so the air conditioner is cooled at low rotation speeds. There was a problem with the shortage. In particular, in light vehicles, etc., the capacitance of the capacitor 2 is small and the allowable limit line t has a steep slope, so that cooling at low rotation speeds is even more difficult than in the case of large vehicles.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to completely stop the drive of the compressor when the pressure of the refrigeration system exceeds the high pressure setting value, and to efficiently adjust the compressor drive according to the engine speed. Our goal is to provide a complete range of vehicle air conditioners that can cool your vehicle.

[Summary of the invention]

In order to achieve all of the above objects, the present invention drives a compressor according to the engine speed to pressurize the refrigerant, and repeats a refrigeration cycle in which the compressed refrigerant is sequentially supplied to the refrigeration system. In a vehicle nitrogen regulator that stops driving the compressor when the pressure exceeds a high pressure setting, the engine rotation speed sensor detects the engine rotation speed and outputs a detection signal that decreases the output level as the engine rotation speed increases. and,
The pressure in the refrigeration system is detected, and the output level increases as the pressure increases. The present invention is characterized in that it includes a drive unit that completely stops driving the compressor when the reference value is exceeded.

[Embodiments of the invention]

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 3 shows the construction of a preferred embodiment of the invention.

In this embodiment, instead of the pressure switch 6 shown in FIG. 1, a pressure sensor 10 that detects the pressure of the refrigeration system and outputs a detection signal whose output level increases according to the increase in pressure,
An engine rotation speed sensor 12 receives rotation pulses generated from the ignition coil 11 to detect the entire engine rotation speed, and outputs a full detection signal whose output level decreases as the engine rotation speed increases; A drive section 13 is provided which sets the output level as a reference value for the high pressure setting value and stops driving the compressor 1 when the output level of the pressure sensor 10 exceeds the reference value.
Since the other configurations are the same as those in FIG. 1, the same components are given the same reference numerals and their explanation will be omitted.

FIG. 4 shows a pressure sensor 10, an engine speed sensor 1
2. A specific configuration of the drive unit 13 is shown.

In FIG. 4, when a pressure sensor 10 connected in series to a power source 8 through a resistor 14 detects the pressure in the refrigeration system, the pressure sensor 10 responds to an increase in pressure P as shown in FIG. 5(A). A detection signal e1 whose output level increases is output, and this detection signal e1 is passed through a noise filter 15 as a detection signal e/l.
It can be supplied to the drive unit 13 as a. Note that the detection signal e1 and the detection signal e/1 are at the same level.

The engine speed sensor 12 is composed of a frequency-voltage converter, and when it receives the rotation pulse from the ignition coil 11, the engine speed r increases as shown in FIG. 5(B). It outputs a detection signal e2 whose output level decreases according to
3 can be supplied.

The drive unit 13 includes a comparator 16 and a relay 17. Comparator 16 is engine speed sensor 1
Detection number 100 e2 of No. 2 can be taken as a reference value for the high pressure setting value of the refrigeration system, and a comparison output can be supplied to the relay 17 when the detection signal e/l from the noise filter 15 exceeds the reference value. The comparison output from the IJL/-17fi comparator 16 allows the drive loop of the magnetic clutch 7 to be completely shut off. That is, as shown in FIG. 5C, the drive unit 13 adjusts the pressure according to the detection output of the pressure sensor 10 and the reference value at which the high pressure setting value P of the refrigeration system decreases as the engine speed r increases. When the pressure detected by the pressure sensor 10 exceeds a reference value, the drive loop of the magnetic clutch 7 can be interrupted and the drive of the compressor 1 can be stopped. Further, since the characteristics shown in FIG. 5(C) match the characteristics of the allowable limit line t shown in FIG. 2, efficient cooling can be performed even when the engine is running at low speed.

FIG. 6 shows the configuration of one embodiment of the pressure sensor 10. As shown in FIG.

6, the pressure sensor 10 is attached to the high-pressure line piping 20 of the refrigeration system via an O-ring 22, and the joint 24 having a mounting screw is tightened to the cover 26 to convert the amount of pressure change into displacement. Together with the diaphragm 28, it is crimped and joined to the case 30.

The diaphragm 28 is provided with a fixed support 36 having a concave tip guide shape and having a contact 34 to which a lead wire 32 is connected to the rear end screwed. When the diaphragm 28 is displaced in accordance with the amount of pressure change, the contactor 34 moves up and down, and the variable resistance value of the sliding resistor 38 placed in contact and opposite to each other is outputted via the terminal 40. The terminal 40 is molded on a metal base 42 with an electrically insulating material such as resin, and is inserted into the case 30. Further, the end face of the terminal 40 is filled with an adhesive 44 in consideration of sealability. The diaphragm 28 is limited by a threaded stop 46 and a metal base 42.

Also, the rotational position of the contactor 34 screwed to the pad 36 is determined by using marks or guide pins when tightening the diaphragm 28 to the case 30.
It is built in so that it does not fall off from 8.

According to this pressure sensor 10, when the diaphragm 28 is displaced in accordance with the pressure within the high pressure line piping 20, a detection signal can be output from the e+k terminal 40 whose output level increases in accordance with an increase in pressure.

As described above, according to this embodiment, when the pressure of the refrigeration system exceeds the high pressure setting value, the drive of the compressor can be stopped, and efficient cooling can be performed according to the engine speed. can.

Furthermore, the characteristic values shown in FIG.
0 as a common part, the engine rotation speed sensor 12.1 drive part 13 can be used as a dedicated part adapted to each refrigerator. Furthermore, in the second embodiment, the frequency of turning on and off the compressor 1 is reduced compared to the conventional one, so that the life of the compressor 1 can be extended.

Further, the pressure sensor 10 is not limited to the above-mentioned embodiment, and may be implemented in the same manner as in the above-described embodiment by using a strain gauge bridge circuit or a cow conductor pressure sensor. Further, the engine rotation speed sensor 12 does not detect the rotation pulse of the ignition coil 11, but it can also detect the three-phase power generation pulse of 1its.

Further, if a comparator having hysteresis characteristics is used as the comparator 16 in the above embodiment, the magnetic clutch 7 can operate smoothly. In addition, as the drive unit 13, a circuit in which the entire reference memory circuit is added to the front stage of the 10D comparator 16 and outputs a relatively large difference in the level of the detection signal el: e'l and e2 can also be used. This can be done in the same manner as in the previous embodiment.

〔Effect of the invention〕

As explained above, according to the present invention, the pressure of the refrigeration system is compared with the reference value at which the high pressure setting value of the refrigeration system decreases as the engine speed increases, and the pressure of the refrigeration system is determined to be the reference value. Since the compressor drive is stopped when the pressure in the refrigeration system exceeds the high pressure set value, the compressor drive can be stopped when the pressure in the refrigeration system exceeds the high pressure set value, and the air conditioner can be efficiently cooled according to the engine speed. There is an excellent effect that can be done.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional air conditioner, Fig. 2 is a diagram showing the relationship between the rotation speed of the compressor and the pressure of the refrigeration system, and Fig. 3 is a basic block diagram showing an embodiment of the present invention. Figure 4 is a specific configuration diagram of the sensor section and drive section shown in Figure 3, and (
A) is a diagram showing the relationship between pressure and voltage (11), Figure 5 (B) is a diagram showing the relationship between engine speed and voltage, and Figure 5 (C) is a diagram showing the relationship between engine speed and voltage. A diagram showing the relationship with pressure, and FIG. 6 is a configuration diagram showing an embodiment of the pressure sensor according to the present invention. 1... Compressor, 2... Capacitor, 4...
Expansion valve, 5... Evaporator, 7... Magnetic clutch, 10... Pressure sensor, 12... Engine speed sensor, 13... & dynamic B(i, 16... Comparator, 17... ...Lille O Agent Patent Attorney Akio Takahashi (12) 7th Figure 2. Number of revolutions (N) - 3rd National 3rd 4th Fog

Claims (1)

[Claims] 1. The compressor is fully driven according to the engine speed to fully compress the refrigerant, and the refrigeration cycle is repeated in which the compressed refrigerant is sequentially delivered to the refrigeration system. When the pressure of the refrigeration system exceeds the high pressure setting value, the compressor is activated. The vehicle air conditioner that stops the drive of the vehicle has an engine speed sensor that detects the engine speed and outputs a detection signal whose output level decreases as the engine speed increases, and an engine speed sensor that detects the total pressure of the refrigeration system. The output level of the pressure sensor outputs a detection signal whose output level increases in accordance with the increase in pressure, and the engine speed sensor is used as a reference value for the high pressure set value, and when the output level of the pressure sensor exceeds the reference value, the compressor is activated. A vehicle air conditioner characterized by having a drive part that stops driving, and a drive part that stops driving.