JPH06340213A - Vehicular air conditioner - Google Patents

Abstract

PURPOSE:To suppress pressure rise, caused by the compression of liquid in a compressor, to a minimum without degrading engine startability. CONSTITUTION:In a vehicular air conditioner constituted in such a way as to stop a blower fan 103 until the materialization of a fan speed restriction release condition at the materialized time of a low water temperature starting condition, the driving force of an engine 101 is transmitted to a compressor 102 within the specified time from the complete explosion of the engine 101 in the case of the low water temperature starting condition and a compressor operating condition being both materialized at the engine starting time, and a control means 105 is provided to control the speed of the blower fan 103 to the specified value or lower until the fan speed restriction release condition is materialized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner for performing low water temperature start control.

[0002]

2. Description of the Related Art In a vehicle air conditioner that uses engine cooling water to warm the air from a blower fan, when the cooling water temperature is low and the outside air temperature is low, the blower fan is stopped for a predetermined waiting time. There is one that performs a so-called low water temperature start-up control that operates the blower fan after the waiting time has elapsed (for example, New Model Car Manual (Y32-1) June 1991 issued by Nissan Motor Co., Ltd.). That is,
Immediately after starting the engine in winter, the outside air temperature is low and the cooling water temperature is low, so the blower fan is stopped for a specified time to prevent cool air from being blown into the passenger compartment, and the cooling water temperature rises to a certain degree to create warm air. After that, drive the blower fan. Further, this type of air conditioner is equipped with a compressor refrigeration cycle cooler unit including a compressor driven by an engine, a condenser, an evaporator, and the like. I'm trying to stop it.

[0003]

By the way, when the vehicle is left with the engine stopped, the temperature of the compressor becomes lower than the temperature of the condenser in the morning to the evening.
In this state, the refrigerant in the refrigeration cycle flows into the compressor and is stored as a liquid refrigerant. When the compressor is started in such a state, pressure due to liquid compression is generated in the compressor. This pressure does not become a problem as long as the driving speed of the compressor, that is, the engine speed at the time of starting the compressor is low, but becomes higher as the driving speed of the compressor becomes higher, and there is a problem that abnormal noise occurs. Therefore, when the liquid refrigerant is stored in the compressor, it is desirable to start the compressor at a low engine speed.

However, in the above-mentioned conventional air conditioner, since the compressor is also stopped during the waiting time during the low water temperature start control, there is a possibility that the compressor will be turned on when the engine speed is high. This will be described below. FIG. 9 shows the engine speed with respect to the time elapsed after the ignition switch is turned on. In the figure, T ₀ is the time when the ignition switch is turned on, T ₁ is the time when the starter motor is turned on, and T ₂ is the complete explosion of the engine. The respective points are shown. Also at time point T ₃
T ₄ indicates the state when the vehicle is accelerating.
When the above-described low water temperature startup control is being performed, both the compressor and the blower fan are stopped for a predetermined time from time T _0, but if it happens that the predetermined time is reached near time T 4, the engine rotation The compressor will be started when the number is quite high. Therefore, when the liquid refrigerant is stored in the compressor at this time, there is a problem that a high pressure is generated by the liquid compression in the compressor as described above and an abnormal noise is generated.

Therefore, if the compressor is driven at a low speed during the operation of the starter motor after the ignition is turned on and before the engine is completely exploded, and the liquid refrigerant is discharged from the inside of the compressor, the above problem can be solved. In this case, a new problem arises that the load on the engine increases and the startability deteriorates.

An object of the present invention is to provide an air conditioning system for a vehicle in which a pressure increase due to liquid compression in a compressor is suppressed to a minimum without deteriorating engine startability.

[0007]

The present invention will be described with reference to FIG. 1 which is a diagram corresponding to claims. In the present invention, a compressor 102 driven by a driving force of an engine 101, a blower fan 103, and a blower utilizing engine cooling water are used. And a heater core 104 that warms the air from the fan 103,
When the low water temperature start condition is satisfied, the blower fan 103 is stopped until the fan speed limit release condition is satisfied, and when the fan speed limit release condition is satisfied, the blower fan 103 is operated. Then, when both the low water temperature starting condition and the compressor operating condition are satisfied at the time of starting the engine, the driving force of the engine 101 is applied to the compressor 10 within a predetermined time after the complete explosion of the engine.
The control means 105 is provided for controlling the speed of the blower fan 103 to a predetermined value or less until the fan speed limit release condition is satisfied. In particular, the invention of claim 2 is such that the speed of the blower fan 103 is maintained at the first speed with the smallest air volume until the fan speed limit release condition is satisfied. Further, the invention of claim 3 is such that the speed of the blower fan 103 is maintained at zero until the fan speed limitation releasing condition is satisfied.

[0008]

When the low water temperature starting condition and the compressor operating condition are both satisfied when the engine is started, the driving force of the engine 101 is transmitted to the compressor 102 and the compressor 102 is started within a predetermined time after the complete explosion of the engine. . Since the engine speed is low within a predetermined time after the complete explosion of the engine, the pressure increase due to the liquid compression can be minimized even if the compressor 102 is driven. Further, at this time, the speed of the blower fan 103 is controlled to be equal to or lower than a predetermined value until the fan speed limit cancel condition is satisfied.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 2, a vehicle air conditioner according to the present invention includes a compressor 22 driven by an engine 21,
Condenser 23, evaporator 24, liquid tank 2
5 and an expansion valve 26, which is a cooler unit of the compression refrigeration cycle, and the evaporator 24 is the air conditioning duct 1.
It is arranged in 00. The outside air introduction port 31 and the inside air introduction port 32 provided in the air conditioning duct 100 are provided with an inside air / outside air switching door 33 that controls an air flow rate introduced into the air conditioning duct 100.

Further, in the air-conditioning duct 100, a blower fan 34, a heater core 35 for warming the air with engine cooling water, and an air mix door 36 are provided as well known, and a vent outlet 41 and a defroster outlet 4 are provided.
2 and the foot outlet 43, and a vent door 44 and a defroster door 45 that adjust the amount of air blown from each outlet.
And a foot door 46 are provided. The air outlet mode is switched by driving each of these doors by an air outlet switching mechanism (not shown). The blowout port mode is, for example, a vent mode in which air is blown out only from the vent blowout port 41, a bilevel mode in which air is blown out from both the vent blowout port 41 and the foot blowout port 42, and air is blown from both the foot blowout port 42 and the defroster blowout port 43. There is a D / F mode for blowing out.

FIG. 3 shows the configuration of the control system of the air conditioner. The air conditioning control circuit 51 includes an outside air temperature sensor 52 that detects an outside air temperature Tamb, an indoor temperature sensor 53 that detects a vehicle interior temperature Tinc, a solar radiation sensor 54 that detects an amount of solar radiation Qsun, and an air temperature downstream of the evaporator 24 (hereinafter, A suction temperature sensor 55 for detecting Tint and a water temperature sensor 56 for detecting the engine cooling water temperature Tw are connected, and an air conditioner switch 57 for instructing the operation of the compressor 22 and a speed (air volume) of the blower fan 34 are manually operated. An air volume changeover switch 58 for changing over is connected. In this embodiment, the blower fan speed can be switched in four stages from the first speed (Lo) with the smallest air volume to the fourth speed (Hi) with the largest air volume by the air volume selector switch 58. The control circuit 51 also includes a blower fan motor 3
A blower fan control circuit 59 for applying a voltage to 4a to drive and control the blower fan 34 is connected.

The control circuit 51 uses the heat load information input from the various sensors described above and the set temperature Tptc set by the occupant to set the air outlet temperature and outlet mode,
The blower fan speed and the like are controlled, and a compressor ON signal is output to the engine control circuit 61 when a compressor operating condition described later is satisfied. Engine control circuit 6
An electromagnetic clutch 22a of the compressor 22 is connected to the motor 1 through a compressor relay 62. The engine control circuit 61 turns on the relay 62 in response to the compressor on signal, whereby the electromagnetic clutch 22a is turned on.
Is turned on to transmit the rotation of the engine 21 to the compressor 22 and drive the compressor 22. Further, reference numeral 60 is an ignition switch whose ON / OFF signal is inputted to both the engine control circuit 61 and the air conditioning control circuit 51. Here, the air conditioning control circuit 51 and the engine control circuit 61 constitute a control means.

Next, the operation of the embodiment will be described with reference to the flow charts of FIGS. FIG. 4 shows an air conditioning control circuit 51
The main routine of the air conditioning control by is shown. This program is started as the starter motor is turned on and then turned off after the ignition switch is turned on (with the complete explosion of the engine). First, in step S10, initial setting is performed, and in the normal auto air conditioner mode. Resets the set temperature Tptc to 25 ° C., for example. In step S20, various information from each sensor is input.
Specifically explaining the data information of each of these sensors,
The set temperature Tptc is supplied from a temperature setting switch provided on the control panel, the vehicle interior temperature Tinc is supplied from the indoor temperature sensor 53, the outside air temperature Tamb is supplied from the outside air temperature sensor 52, and the solar radiation amount Qsun is supplied from the solar radiation sensor 54.

Next, in step S30, the outside air temperature sensor 5
The outside air temperature Tamb obtained from No. 2 is processed to a value Tam corresponding to the actual outside air temperature Tamb by removing influences from other heat sources. Next, in step S40, the solar radiation amount information Qsun as the light amount from the solar radiation sensor 54 is processed into a value Q'sun as the heat amount suitable for the subsequent calculations. In step S50, the set temperature Tptc set above is processed into a value T'ptc corrected according to the outside air temperature Tamb. In step S60, the target blowout temperature T is calculated from Tam, Tinc, Q'sun, T'ptc.
In addition to calculating o, the opening degree of the air mix door 36 is controlled according to To. As a result, the mixing ratio of the amount of air passing through the heater core 35 and the amount of air not passing through the heater core 35 is adjusted, and the temperature of air blown out from the air outlet is adjusted.

In step S70, the target outlet temperature To is
The outlet mode is determined according to. In step S80, the suction port, that is, the outside air introduction port 31 and the inside air introduction port 32
Control selection switching of. In step S90, the blower fan 34 is controlled to control the air volume from the air outlet. In step S100, the compressor 22 is controlled. Then, the process returns to step S20.

FIG. 5 shows details of the air volume control in step S90. First, in step S901, it is determined whether or not the air volume changeover switch 58 is operated. If it is operated, a voltage corresponding to the operation of the switch 58 is applied to the blower fan motor 34a in step S902, and 1
The blower fan 34 is driven at any one of the fourth speed to the fourth speed. If the switch 58 is not operated, step S90
In step 3, it is determined whether or not the air outlet mode is set to the D / F mode. Here, the D / F mode is normally set when the outside air temperature is lower than 15 ° C., that is, during heating. If it is determined that the blower fan is not in the D / F mode, the process proceeds to step S904, where the blower fan applied voltage is determined based on the target blowout temperature To, and the determined voltage is output via the blower fan control circuit 59 to the blower fan motor 34a. To drive the blower fan 34.

On the other hand, if it is determined that the D / F mode is set, the flow advances to step S905. In step S905, the engine cooling water temperature Tw is determined. If Tw is greater than or equal to the predetermined value Tw ₁ , the process proceeds to step S904, and if it is less than Tw ₁ , the process proceeds to step S906. Here, step S
If both 903 and step S905 are affirmed, it means that the outside air temperature is low and the engine cooling water temperature is also low. In this embodiment, this state is determined to satisfy the low water temperature starting condition. Further, the low outside air temperature can be said to be a condition under which the liquid refrigerant easily accumulates in the compressor.

In step S906, it is determined whether the compressor operating condition is satisfied. The air conditioner switch 57 is turned on, and the outside air temperature Tam is the predetermined temperature T.
If it is equal to or higher than am ₁ and the suction temperature Tint is equal to or higher than the predetermined temperature Tint ₁ , it is determined that the compressor operating condition is satisfied and the process proceeds to step S910, and if not, the process proceeds to step S907. In step S907, it is determined whether or not this is the first processing after the activation of the air conditioner, and if the result is negative, step S907
If the determination is affirmative, in step S908, the low water temperature control waiting time t ₁ is calculated based on the target outlet temperature To, and the process proceeds to step S909. The waiting time t ₁ is calculated to be longer as the target outlet temperature To is higher, that is, as the strong heating is required. The maximum value of t ₁ is about 200 seconds.

In step S909, the blower fan applied voltage is controlled according to the characteristics shown in the drawing based on the elapsed time from the start of the air conditioner. According to this characteristic, the applied voltage, that is, the blower fan air volume is maintained at zero until the waiting time t ₁ has elapsed from the start of the air conditioner, and the applied voltage gradually rises after the time t _{1 has} elapsed. As a result, it is possible to prevent the cool air from being blown into the vehicle interior immediately after the engine is started.

On the other hand, if it is determined in step S906 that the compressor operating condition is satisfied, step S906
Proceeding to 910, it is determined whether or not it is the first process after the activation of the air conditioner. If step S910 is denied, step S9
If it is affirmed in Step S911,
The waiting time t _{2 of the} low water temperature control based on the target outlet temperature To
Is calculated and the process proceeds to step S912. This waiting time t ₂
Is calculated to be longer as the target blowout temperature To is higher, that is, when stronger heating is required. Note that t ₁ = t ₂ may be set.

In step S912, the blower fan applied voltage is controlled according to the characteristics shown in the drawing based on the elapsed time from the start of the air conditioning control. According to this characteristic, the applied voltage is kept at a predetermined value until the waiting time t ₂ elapses from the start of the air conditioner, and the blower fan speed (air volume) is the first speed (L
o). The applied voltage gradually rises after the elapse of time t ₂ .

FIG. 6 shows details of the compressor control in step S100. In step S101, it is determined whether or not the above-mentioned compressor operating condition is satisfied, and if so, a compressor on signal is output to the engine control circuit 61 side in step S102. If the compressor operating condition is not satisfied, step S103
Press to cancel the compressor signal output.

FIG. 7 is a flowchart showing only the compressor on / off control by the engine control circuit 61. This program is started when the ignition switch 60 is turned on. First, at step S1, it is determined whether or not the starter motor has just been turned on and then turned off, that is, whether or not the engine has just completed a complete explosion. If denied, step S1 remains; if affirmed, step S1
In step 2, it is determined whether 0.5 seconds has elapsed since the complete explosion of the engine. If negative, the process returns to step S1, and if positive, the process proceeds to step S3.

In step S3, the air conditioning control circuit 5 is
It is determined whether or not the compressor on signal is input from 1. If it is input, the compressor relay 62 is turned on in step S4, and if it is not input, step S4 is performed.
At 5, the compressor relay 62 is turned off. When the compressor relay 62 is turned on, the electromagnetic clutch 22a of the compressor 22 is turned on and the driving force of the engine is increased by the compressor 2
2 and the compressor 22 is driven. When the relay 62 is turned off, the electromagnetic clutch 22a is turned off, the driving force of the engine is cut off, and the compressor 22 is stopped.

According to the above-described procedures of FIGS. 4 to 7, when the compressor operating condition is satisfied at the time of engine start, even if the low water temperature starting condition is satisfied, the compressor ON signal is immediately output. Output to the engine control circuit 61, and 0.5 seconds after the complete explosion of the engine, the compressor 22
Is started. Normally, the engine speed is considerably low within 1 second after the complete explosion of the engine. Therefore, if the compressor 22 is started 0.5 seconds after the complete explosion, the pressure increase in the compressor due to the liquid compression even if the compressor 22 is driven. Can be suppressed to a minimum and there is no inconvenience such as abnormal noise. Then, since the liquid refrigerant inside the compressor 22 is discharged to the condenser 23 side by driving the compressor at the time of low engine speed, high pressure does not occur inside the compressor even if the engine speed thereafter increases. Further, since the compressor is started after the engine has completely exploded, there is no influence on the engine startability. Further, the fact that the compressor operating condition is satisfied in the case where the low water temperature starting condition is satisfied (during heating) almost always means that the occupant turns on the air conditioner switch 57 to remove the fog on the window. By starting the compressor 22 immediately after the complete explosion of the engine (0.5 seconds later) as described above, there is also an advantage that the window transparency can be improved.

Further, in this embodiment, when both the low water temperature starting condition and the compressor operating condition are satisfied, the blower fan 34 is operated until the time t ₂ elapses, that is, until the fan speed limit releasing condition is satisfied. The speed is kept at Lo. Here, when the blower fan is stopped, the amount of air passing through the evaporator 24 becomes almost zero, and if the compressor 22 is driven at this time, the evaporator may freeze. However, in the present embodiment, by driving the blower fan 34 with Lo as described above, a small amount of air passes through the evaporator 24, so the risk of freezing of the evaporator 24 can be reduced. In this case, the cold air is blown into the passenger compartment, but since it is a small amount, it does not give an occupant an uncomfortable feeling. If the compressor operating condition is not satisfied when the low water temperature start condition is satisfied,
As in the conventional case, the compressor 22 is not driven, and the blower fan is stopped until the waiting time t ₁ elapses.

FIG. 8 shows a flowchart in which step S912 in FIG. 5 is replaced with step S912 '. In other words the previous embodiment, when the low temperature activation condition and compressor operation condition is satisfied together, although the blower fan speed until the time t ₂ has elapsed to hold in Lo, the time in the present embodiment t ₂ Stop the blower fan until has elapsed. In this case, the amount of air passing through the evaporator 24 becomes substantially zero even though the compressor is operating, but the suction temperature Tint detected by the suction temperature sensor 55 is the predetermined temperature Ti as described above.
When it is less than nt ₁ , the compressor operating condition is not satisfied, so the compressor 22 is stopped by the compressor off signal, and there is no fear of evaporator freezing.

In the above description, the compressor 22 is operated 0.5 seconds after the complete explosion of the engine. However, the compressor starting time is not limited to 0.5 seconds after the complete explosion of the engine, and the low engine speed within a predetermined time after the complete explosion is reached. Just time. Further, in the above, when the low water temperature start condition is satisfied, it is determined that the fan speed limit release condition is satisfied when the predetermined time t ₁ or t ₂ has elapsed from the operation of the air conditioner.
Instead of this, the blower fan speed may be increased by determining that the fan speed limit release condition is satisfied when the engine cooling water temperature Tw becomes equal to or higher than the predetermined temperature Tw ₂ . Here, the above-mentioned predetermined temperature Tw ₂ is determined by the above step S9
The temperature is lower than the temperature Tw ₁ compared in 05. Further, the low water temperature starting condition is not limited to the embodiment, and for example, if the detected value Tamb or Tam of the outside air temperature is less than the predetermined temperature, it may be determined that the low water temperature starting condition is satisfied.

[0029]

According to the present invention, when the low water temperature starting condition and the compressor operating condition are both satisfied at the time of starting the engine, the compressor is started within a predetermined time after the complete explosion of the engine. The compressor can be started when the engine speed is low, and the rise in the internal pressure of the compressor can be suppressed to a minimum without deteriorating the engine startability. Further, the blower fan air flow rate is controlled to be equal to or less than the predetermined amount until the fan speed limit release condition is satisfied, so that the occupant's discomfort due to the cold air blowing can be minimized. In particular, according to the second aspect of the invention, the speed of the blower fan is kept at the first speed with the smallest air volume until the fan speed limitation release condition is satisfied. Therefore, the amount of cold air blowout is suppressed to a minimum and the evaporator Freezing can be prevented. Further, according to the third aspect of the invention, the speed of the blower fan is kept at zero until the fan speed limitation release condition is satisfied, so that the cold air blowing amount can be made zero and the passenger's discomfort can be reliably prevented.

[Brief description of drawings]

FIG. 1 is a complaint correspondence diagram.

FIG. 2 is a configuration diagram showing an embodiment of a vehicle air conditioner according to the present invention.

FIG. 3 is a block diagram showing a control system of the air conditioner.

FIG. 4 is a flowchart showing a main routine of air conditioning control.

FIG. 5 is a flowchart showing a detailed procedure of air volume control.

FIG. 6 is a flowchart showing a detailed procedure of on / off decision control of the compressor.

FIG. 7 is a flowchart showing a procedure of actual compressor on / off control.

FIG. 8 is a flowchart showing another embodiment of air volume control.

FIG. 9 is a diagram illustrating a conventional problem.

[Explanation of symbols]

 21 Engine 22 Compressor 22a Electromagnetic Clutch 23 Condenser 35 Heater Core 24 Evaporator 34 Blower Fan 51 Air Conditioning Control Circuit 61 Engine Control Circuit

Claims (3)

[Claims] 1. A compressor that is driven by the driving force of an engine, a blower fan, and a heater core that warms the air from the blower fan by using engine cooling water. In a vehicle air-conditioning system in which the blower fan is stopped until the fan speed limit release condition is satisfied, and the blower fan is operated when the fan speed limit release condition is satisfied, a low water temperature starting condition and a compressor operating condition when the engine is started. If both are satisfied, the driving force of the engine is transmitted to the compressor within a predetermined time after the complete explosion of the engine, and the speed of the blower fan is set to a predetermined value or less until the fan speed limit release condition is satisfied. An air conditioner for a vehicle, comprising a control means for controlling. 2. The vehicle air conditioner according to claim 1, wherein the control means keeps the speed of the blower fan at the first speed with the smallest air volume until the fan speed limit release condition is satisfied. . 3. The vehicle air conditioner according to claim 1, wherein the control unit keeps the speed of the blower fan at zero until the fan speed limit release condition is satisfied.