JPH0356202B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an air conditioner for a vehicle, particularly an improved air conditioner that can perform efficient cooling by preventing a rise in refrigerant pressure during cooling operation. Related to vehicle air conditioner.

[Prior Art] During cooling operation by a vehicle air conditioner, a large amount of energy is lost and a large load is placed on the engine. In view of the size, economy, and safety of the vehicle air conditioner, a vapor compression method is generally used in which the refrigerant is continuously evaporated.

That is, as is well known, refrigerant gas is sucked and compressed by a compressor to become a high-temperature, high-pressure gas, and then
The refrigerant is sent to a condenser, where it is cooled and liquefied, and then sent to an expansion valve where it is rapidly expanded and turned into a low-temperature, constant-pressure atomized refrigerant that is sent to an evaporator. This evaporator removes latent heat from the surrounding air and vaporizes it, which is then sucked into the compressor again.
It is repeatedly circulated through the refrigeration cycle to perform a cooling effect.

However, for example, when parking under the hot sun,
When rapid cooling of the vehicle interior by the air conditioner is performed continuously under engine racing conditions (for example, when the engine speed increases under no-load conditions due to activation of the air conditioner, hereinafter simply referred to as racing), the cooling air in the condenser When the temperature rises and the liquefaction of the refrigerant becomes insufficient, a situation occurs in which the refrigerant pressure in the compressor increases abnormally.

In such cases, conventionally, the operation of the compressor was temporarily stopped.

In other words, as shown in FIG. 4, in conventional control by an air conditioner, the fan motor 10 of the sub-radiator placed near the main radiator is activated when the water temperature of the main radiator reaches a predetermined value (T ₂ °C) or higher. , water temperature switch 12 is OFF
As a result, the relay coil 14a of the fan relay 14 becomes de-energized, and the relay contact 14b
As a result, the fan motor 10 of the sub-radiator rotates.

In addition, independently of this, the cooler high pressure switch 16 sets the refrigerant pressure in the cooler to a predetermined value (P ₁
Kg/cm ² ) or more, it is turned ON, and as a result, the relay coil 18 of the compressor cut relay 18
a is in an excited state, and relay contact 18b is activated.
As a result of being turned off, the driving of the compressor 19 is stopped.

In order to drive the compressor 19 again, a control means is used that waits until the refrigerant pressure in the cooler drops to a constant value, regardless of the detected value of the radiator water temperature.

[Problems to be solved by the invention] Conventional problems However, as mentioned above, when the refrigerant pressure rises abnormally, in order to operate the air conditioner again, the refrigerant pressure must drop to a certain value. As a result, it became impossible to cool the interior of the vehicle during this time, and the occupants had to experience discomfort for a long time.

Purpose of the Invention The present invention has been made to solve the above problems, and is mainly intended for use in vehicles that can prevent the refrigerant pressure from increasing in the cooling condenser when performing cooling operation in an engine racing state when parked under the scorching sun. The purpose is to provide air conditioners.

[Means and effects for solving the problems] In order to achieve the above object, the present invention is arranged facing a ventilation passage between a cooling condenser and a main radiator, and is arranged to face the ventilation passage between the cooling condenser and the main radiator, and to drain the air in the ventilation passage. A sub-radiator with a fan that discharges the air to the side, an engine speed detection sensor that detects the engine speed,
A shift position detection sensor that detects the shift position of the vehicle gear, a refrigerant pressure detection sensor that detects the refrigerant pressure of the cooling condenser, and signals from these detection sensors are received to determine if the engine rotation speed is above a predetermined value. The present invention is also characterized by comprising a control device that drives the fan of the sub-radiator when the refrigerant pressure in the cooling condenser is equal to or higher than a predetermined value and the shift position is when the vehicle is stopped.

According to the above configuration, signals from each detection sensor are input to the control device, and when the engine rotation speed and the refrigerant pressure of the cooling condenser are above predetermined values and the shift position is when the vehicle is stopped, the sub-radiator is fans will be driven.

In this case, since the sub-radiator is disposed facing inside the ventilation path between the cooling condenser and the main radiator, the air in the ventilation path is exhausted to the side.

This increases the amount of air passing through the cooling condenser, increases the cooling capacity of the cooling condenser, and prevents the refrigerant pressure from increasing excessively.

In addition, the hot air that has passed through the main radiator is guided by the exhaust action of the sub-radiator and flows to the side, preventing the hot air from going around to the cooling condenser, thereby reducing the cooling effect of the cooling condenser and the main radiator. improves.

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

FIG. 1 is an explanatory diagram showing the flow of cooling air in a vehicle air conditioner according to the present invention.

In the figure, the vehicle to which the present invention is applied includes a main radiator 20, a cooling condenser 22,
A sub-radiator 24 is provided adjacent to the main radiator 20 and on the side of the ventilation passage from the cooling condenser 22 to the main radiator 20 so as to take in air from this ventilation passage and exhaust it to the side of this ventilation passage. It is placed in place. Although not shown in the figure, the cooling condenser 22 includes a compressor that sucks in and compresses refrigerant gas, an expansion valve that expands the liquefied refrigerant into a mist of refrigerant, and further vaporizes the atomized refrigerant. The refrigerating cycle is connected to an evaporator that cools the inside of the vehicle.

FIG. 2 shows the circuit configuration used in the present invention.

In the figure, a fan motor 24a of a sub-radiator 24 is controlled by a fan relay 26, and its relay coil 26a
is connected to the control computer 28, and the relay contact 26b is connected to the fan motor 24a of the sub-radiator 24. This relay contact 26
b is ON when the relay coil 26a is de-energized.
(make up).

The control computer 28 includes a transistor 30, an inverter circuit 32, and an AND circuit 3.
4, the collector side of the transistor 30 is connected to the relay coil 26a of the fan relay 26, and the emitter side is connected to the water temperature detection sensor 36 of the main radiator 20.

Further, on the input side of the AND circuit 34, a comparison circuit 40 that receives a signal from an engine rotation speed detection sensor (tachometer) 38 and determines whether the rotation speed is equal to or higher than a predetermined value, and a shift position detection sensor a detection circuit 44 that accepts the signal and determines whether the shift position is in the N (neutral) or P (parking) range, and the cooling capacitor 2
A comparison circuit 48 is connected which receives a signal from the second refrigerant pressure detection sensor 46 and determines whether the refrigerant pressure is equal to or higher than a predetermined value.

To explain the operation of the present invention with the above configuration, first, when the ignition switch 50 is turned on, the detection circuit 44 detects that the shift position is in the N (neutral) or P (parking) range. (while the vehicle is stopped),
The detection circuit 44 outputs a logic signal "1", and at other times (during normal running), a logic signal "0" is output. Further, when the comparator circuit 40 detects that the engine speed is equal to or higher than a predetermined value (N ₁ rpm), the comparator circuit 40 outputs a logic signal "1".
is output and the engine speed reaches the specified value (N ₂ rpm)
When it is below, a logic signal "0" is output. Further, when the comparator circuit 48 detects that the refrigerant pressure is equal to or higher than the predetermined value (P ₁ Kg/cm ² ), the comparator circuit 48 outputs a logic signal “1” and the refrigerant pressure reaches the predetermined value (P ₂ Kg/cm 2 ). kg/ ^cm2 ) or less,
A logic signal "0" is output.

On the other hand, the water temperature detection sensor 36 is turned OFF (broken) when the water temperature of the main radiator 20 is above a predetermined value (T ₂ °C), and turned ON (made) when it is below a predetermined value (T ₁ °C). Ru.

Therefore, when the water temperature of the main radiator 20 is above a predetermined value (T ₂ °C), the control computer 2
Regardless of the output state from 8, the fan motor 24a of the sub-radiator 24 is driven to a predetermined value (T ₁ °C).
In the following cases, the fan motor 24a is controlled by the output state of the control computer 28.

The output of the control computer 28 is sent to the detection circuit 44.
and the three outputs of comparison circuits 40 and 48 are all “1”
In other words, during racing when the vehicle is stopped, when the engine speed is above a predetermined number and the refrigerant pressure is above a predetermined value, the transistor 30 becomes OFF, and as a result, the relay contact 2
6b is turned on (make), and the fan motor 24a of the sub-radiator 24 rotates.

Further, the detection circuit 44 and the comparison circuits 40 and 48
When any one of the three outputs is a logic signal "0", the transistor 30 is turned on,
In this case, the fan motor 24a of the sub-radiator 24 is controlled depending on the state of the water temperature detection sensor 36, as described above.

Note that the detected values of engine speed N ₁ , refrigerant pressure P ₁ , and water temperature T ₂ have some width,
The reason why so-called hysteresis is provided is to eliminate detection errors due to fluctuations in detected values.

In addition, the fan motor 24 of the sub-radiator 24
When a rotates, the amount of air passing through the cooling condenser 22 increases, and the main radiator 2
The hot air after passing zero is discharged to the outside of the vehicle by the fan motor 24a of the sub-radiator 24, resulting in the effect that the hot air does not go around the front surface of the cooling condenser 22.

Next, FIG. 3 shows a circuit configuration according to another embodiment circuit, and this embodiment has the same structure except that a relay is used in place of the transistor 30 in FIG. The logical operation is the same as above.

To explain this simply, the motor fan 124a of the sub-radiator is driven unconditionally when the water temperature detected by the water temperature detection sensor 136 is T ₂ °C or higher.
When the water temperature is below T ₁ °C, it is controlled by the following conditions.

That is, the shift indicator 142 indicating the shift position is in the N (neutral) or P (parking) position, the refrigerant pressure is _P1 or more, and the engine rotation speed is detected by the engine rotation speed detection sensor (tachometer) 138. When the number is above N1rpm, the refrigerant pressure detection sensor 146 is ON.
state (make), and as a result, the output side transistor 52 of the amplifier circuit 140 is in the OFF state.
Relay contact 54b of relay 54 is ON (make)
state, while relay contact 5 of relay 56
6b is turned OFF (broken), and as a result, relay 1
26 contact 126b turns on (makes), and the motor fan 124a of the sub-radiator rotates.

If the water temperature is below T ₁ ℃ and the shift position is
If even one of the refrigerant pressure and engine speed does not satisfy the above conditions, the fan motor 124a is not rotated.

As explained above, according to this embodiment, the control computer 28 determines the logic of the signals from the engine rotation speed detection sensor 38, the shift position detection sensor 42, and the refrigerant pressure detection sensor 46, and the logic signal According to the logical sum condition of and the signal of the water temperature detection sensor 36 of the main radiator 20,
The fan motor 24a of the sub-radiator 24 is controlled.

Therefore, when the water temperature in the main radiator 20 reaches a predetermined value or higher, or when the refrigerant pressure in the air conditioner increases, the fan motor 24a of the sub-radiator 24 is automatically driven.
Can effectively prevent the increase in refrigerant pressure,
Continuous operation of in-house cooling becomes possible.

[Effects of the Invention] As explained above, according to the vehicle air conditioner according to the present invention, the sub-radiator is arranged facing the ventilation passage between the cooling condenser and the main radiator, and the sub-radiator is arranged facing the ventilation passage between the cooling condenser and the main radiator. Since the air is exhausted to the side, the amount of air passing through the cooling condenser can be increased, increasing the cooling capacity of the cooling condenser, and the hot air discharged from the main radiator can also be circulated around the cooling condenser. It is possible to effectively prevent this.

Therefore, the cooling efficiency of the cooling condenser and the main radiator is increased, and while an excessive rise in refrigerant pressure in the cooling condenser is prevented, stable continuous operation of cooling the vehicle interior is possible.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the flow of cooling air in a vehicle air conditioner according to the present invention, Fig. 2 is an explanatory diagram of a circuit configuration used in the present invention, and Fig. 3 is an explanatory diagram of a circuit configuration showing another embodiment. 4 are circuit explanatory diagrams of a conventional vehicle air conditioner. 20...Main radiator, 22...Cooling condenser, 24...Sub radiator, 24a...Fan motor, 28...Control computer, 36...Water temperature detection sensor, 38...Engine rotation speed detection sensor, 42
...Shift position detection sensor, 46...Refrigerant pressure detection sensor.

Claims (1)

[Scope of Claims] 1. A sub-radiator with a fan that is disposed facing the ventilation path between the cooling condenser and the main radiator and exhausts air in the ventilation path to the side, and detects the rotational speed of the engine. a shift position detection sensor that detects the shift position of the vehicle gear; a refrigerant pressure detection sensor that detects the refrigerant pressure of the cooling condenser; and a refrigerant pressure detection sensor that detects the refrigerant pressure of the cooling condenser. A control device that drives the fan of the sub-radiator when the rotational speed is at least a predetermined value, the refrigerant pressure in the cooling condenser is at least a predetermined value, and the shift position is when the vehicle is stopped. Air conditioner for vehicles.