JPH045121A - Air conditioner for use in automobile - Google Patents

Abstract

PURPOSE:To prevent complete freezing of the evaporator by calculating the anticipated wind velocity of a blown air from a physical quantity corresponding to the amount of air from a blower, comparing this wind velocity with a detected value indicated by a wind velocity sensor so as to make a decision on the freezing of the evaporator, and disconnecting the compressor from a power source to stop its cooling operation when the evaporator has been decided as being in a condition of freezing. CONSTITUTION:The air conditioner comprises a heat exchanger 1 which includes two air mixing doors 14, 15 and a mode door 19 for controlling the proportion or ratio between the vent blow-off air amount and the floor blow-off air amount. The air mixing door 15 is so controlled as to more increase the proportion of air amount bypassing a heater 16 as the temperature difference between the floor blow-off air temperature indicated by a wind-velocity sensor 27 and a target value thereof becomes smaller. Further, the mode door 19 is controlled by a detected value of the wind-velocity sensor 27 so as to provide a predetermined wind distribution ratio. In this case, a wind velocity Gj, which is obtained by multiplying a wind velocity the wind velocity sensor 27 will detect by a specified coefficient, is calculated in accordance with the specified characteristics procured using the blow-off ports and the voltage Vm of a motor 9. This wind velocity Gj as calculated is compared with a detected wind-velocity value G. And when the latter G is smaller than the former Gj, the evaporator is decided as being in a condition of freezing, thus to stop the compressor operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an evaporator freeze detection means using a wind speed sensor in an automobile air conditioner.

[Conventional technology]

As described in Utility Model Application Publication No. 60-192610, page 4, line 7 to line 16, in the conventional device, a freezing sensor is installed in the part of the evaporator that is prone to freezing, and after freezing is detected, the evaporator is stopped. The plan was to shift to thermostatic control, which maintains the chamber temperature at a predetermined value.

[Problem to be solved by the invention]

In the above conventional technology, the suction air temperature is low and the evaporator temperature is
No consideration has been given to dehumidifying operation at low outside temperatures where the air temperature is cooled to below 'C' and dehumidifying, and even if the evaporator temperature freezes due to locking of the blower motor, the temperature does not change and it is difficult to judge. there were.

An object of the present invention is to prevent the evaporator from completely freezing and to continue air conditioning even when the intake air temperature is low.

[Means to solve the problem]

In order to achieve the above object, the present invention provides an air blower,
An air conditioner for an automobile comprising an evaporator that cools blown air, a compressor that circulates refrigerant to the evaporator, and a control means that connects the compressor and a power source intermittently. further, the control means determines a predetermined value of the wind speed from the detected physical quantity using a relationship between a predetermined air flow rate of the blower and a related physical quantity of the blower; The compressor is provided with means for separating the compressor and the power source when the detected value of the wind speed is less than the predetermined value.

[Effect]

In the present invention, the predicted wind speed of the blown air is determined from the physical quantity related to the air flow rate of the blower, and by comparing it with the value detected by the wind speed sensor, it is possible to determine whether the evaporator is frozen. Upon determining that the compressor is frozen, the compressor is separated from the power source;
Since cooling is stopped, complete freezing does not occur and air conditioning can be continued.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 to 13.

FIG. 1 shows a block diagram of this embodiment. In other words, it consists of the following five devices. Heat exchange device 1. Air conditioning electronic control device that controls the heat exchanger W1 2. Compressor for cooling 3. It consists of a compressor electronic control unit w4 that controls the compressor 3, an engine control electronic control unit 5, and the like.

The heat exchange device 11 and the electronic control device 2 for air conditioning are
This is a known device as shown in FIG. 1 of Japanese Patent No. 1-205504.

An overview of this embodiment will be explained. The heat exchange device 1 consists of the following three units. Inside air inside the vehicle 6 or outside air 7
8. Intake door that controls the suction rate of. Then, an intake blower unit 11 consisting of a blower 10 driven by a motor 9 and a cooling unit 13 containing a built-in evaporator 12 that cools the air using the latent heat of vaporization of the refrigerant circulated by the compressor 3 reheat the cooled air. Two air mix doors 14, 15. A 16° heater that uses engine cooling water (temperature, approximately 80°C), and
This heater unit 20 has a built-in mode door 19 that controls the ratio of the vent air 17 blowing out to the upper body and the floor air blowing 18 blowing out to the feet.

The air conditioning electronic control device 2 is configured to set a target temperature Ts given by a volume 21 linked to a temperature setting lever provided on the operation panel.
The heat exchange device 1 is controlled so that the interior of the vehicle becomes as follows.

The temperature T in the vehicle interior is determined by an upper vehicle interior temperature sensor 22 installed on the ceiling and a lower vehicle interior temperature sensor 23 located at the foot of the vehicle.
Furthermore, the detected value Ta of the outside air temperature sensor 24,
And, from the detection value 2 of the solar radiation sensor 25, the vent blowout 1
7 and the target temperature T a u o of the floor air outlet 18,
Decide on Ta t o.

The intake door 8 is controlled so that the smaller the temperature difference Tduo'rdu between the vent outlet temperature T au detected by the vent outlet temperature sensor 26 and its target value Tduo, the greater the internal air intake ratio.

The motor 9 of the blower 10 is operated at a voltage of ■ so that the larger the absolute value I Ts - TrI of the temperature difference between Tr and Ts, the greater the air volume.
Increase yo. In other words, the wind speed is determined by T.

The air mix door 114 has a temperature difference (Tdu).

Tdu) is smaller, the proportion of airflow that bypasses the heater 16 is increased.

The air mix door l115 detects a temperature difference (T a to T da
) is smaller, the proportion of airflow that bypasses the heater 16 is increased. In other words, this is the fifth invention in which temperature control is performed using the wind speed sensor 27.

Mode door 19 was chosen from Ta and Z. Vent blowout 1
7 and floor outlet 18.

Control is performed using a floor airflow speed sensor 27 provided on the floor airflow 18. That is, the wind speed sensor 27 is provided downstream of the mode door 19 that determines the air distribution ratio, and the air distribution is controlled based on the detected value.

The wind speed sensor 27 has the same principle as the air flow meter known in Service Bulletin No. 491 (BL-14) published by Nissan Motor Co., Ltd., October 1988, pages 1-64 to 11-65. That is, it consists of two thermistor sensors, one of which measures the temperature Tdt of the blown air, and the other which generates heat to maintain a constant temperature.

The wind speed G is determined by correcting the current applied to the latter sensor with the temperature Td1.

The compressor electronic control device 4 receives information from the air conditioning electronic control device 2, the detected value Tt of the inlet air temperature sensor 28 of the evaporator 12, and the detected value Te of the outlet air temperature sensor 29.
, the magnetic clutch 31 of the compressor 3 and the control valve coil 32 are controlled based on the detected value Ne of the engine speed sensor 30. The details are shown in Figures 2 to 12.
This will be explained using the flow shown in the figure.

The engine control device 5 is based on service bulletin No. 578 (YAI-1, YBI-1) published by Gosan Jidosha Co., Ltd.
It has the same function as the device described on pages B-62 to B-65 published in June 2016. That is, the air flow meter 33
The basic injection amount (T
p), a correction value Co determined by the detected value of the engine rotation speed sensor 30, etc. is added to determine the fuel injection amount and control the fuel injection time of the injector 34 that supplies fuel to the engine.

Next, the operation of the compressor electronic control device 4 will be explained using a processing flow of a microcomputer that performs calculations, judgments, etc. for control.

The microcomputer of this embodiment includes a central control unit W (hereinafter referred to as CPU) and a processing procedure (program).

Read-only memory (hereinafter referred to as ROM') that stores constants)
), random access memory (hereinafter referred to as RAM) for storing data, input/output terminal (hereinafter referred to as l10), analog
Digital conversion Kugata terminal (below).

A/D), an arbitrary width pulse output terminal (hereinafter referred to as PWM), and a serial communication input terminal (hereinafter referred to as 5CI) are built-in. For example, the microcomputer HD6305Z manufactured by Hitachi, Ltd. is used.

A crystal oscillator with a frequency of I MHz, which constitutes an oscillator that determines the basic cycle, is connected to the microcomputer.6 The program of the microcomputer repeatedly executes the background job shown in Figure 2 (hereinafter referred to as , BGJ, the execution cycle of this embodiment is approximately 0.1 seconds) and the time interrupt function, and is executed at fixed time intervals (5 milliseconds in this embodiment) as shown in Fig. 3. , TIMER).

After starting the BGJ in FIG. 2 with the engine switch, in step 100, the BGJ initializes Ilo, RAM, etc.
Thereafter, the processes from step 101 to step 109 are repeated.

In step 101, between the air conditioning electronic control device 2,
Data communication is performed using SCI. The following information is received from the air conditioning electronic control device 2.

Position of intake door 8, floor air distribution ratio R, t
l Voltage of motor 9■1. Outside air temperature Ta, vent blowout 17
The target temperature TduO1 and the detected temperature Tdu.

In step 102, the temperature Ts detected by the inlet air temperature sensor 28, the temperature Te detected by the outlet air temperature sensor 29, and the rotation speed Ne detected by the engine rotation speed sensor 30 are inputted via the A/D.

In step 103, calculations shown in FIG. 4 are performed. In step 300, the heating rate by the heater 16 is determined by the temperature difference (
According to the characteristics shown in the figure, the permissible value of T 110 increase per unit time Ta history + m is determined.

In step 301, similarly to step 300, the permissible value T dt i m of the target temperature Tea increase of the evaporator outlet air per unit time is determined according to the characteristics shown in the figure. In step 302, based on the information on Ta received in step 101 and the position of the intake door 8, T is determined according to the characteristics shown in the figure.
ea Determine a.

Returning to FIG. 2, in step 104, it is determined according to the flowchart of FIG. 5 whether to perform fixed control on the maximum capacity side for rapid cooling or normal control which is controlled according to the load. In step 400, it is determined whether a flag Fc defined in the RAM indicating that rapid cooling is in progress is set, that is, 1. If true, in step 401, Td
It is determined whether u has become colder than the target value T duo.

If false, the process proceeds to step 402, where it is determined whether Tduo is lower than the level T du c that requires rapid cooling control. If false, in step 403, the flag F
Clear c and set the flag Fs indicating the end of rapid cooling control to 1.
Make it.

If the result in step 400 is false, proceed to step 404;
Determine whether the flag Fs is 1.

If true, the flag Fc is set to O in step 405.

Returning to FIG. 2, in step 105, it is determined whether the flag Fc is 1. If true, in step 106, the target energizing current I5O1o of the control valve coil 32 is set to OA, a fixed state on the maximum capacity side. On the other hand, in step 107, the sixth
Perform the control shown in the figure.

In step 500, the possibility of freezing of the evaporator 12 is determined based on the temperature difference Tea Te, and in step 501, the process branches.

In step 502, the need for cooling is determined by the temperature difference Tduo
It is determined based on Tdu, and if T au is low temperature, a Td sub-control determination is made in step 503, and a flag Ft indicating Te control is set to O in step 504.

If the determination is true in step 501, step 505
Then, set the flag F to 1.

In step 506, it is determined whether or not the flag F is 1. If it is 1, Te control is performed in step 507, and if it is O, Te control is performed in step 508.

Take control. Details of each control are shown in Fig. 7.

and shown in FIG.

The flow shown in FIG. 7 will be explained. In step 600, it is determined whether the flag Ft was 1 last time. Step 6
At 01, it is determined whether Tea has risen above the current outlet air target temperature Teoz. If true, in step 602, it is determined whether a flag Fe indicating the execution time of the Tea increase restriction process is 1 or not. Note that the flag Fe is set in the flow of FIG. 3, TIMER, which will be described later.

In step 603, the flag Fe is set to O, and in step 6
At 04, the temperature difference T e a T e o i is the upper limit T
Determine whether or not e o m is exceeded. Step 6
In 05, a new T e o
x, and in step 606, Tea is set to a new Te
Let it be oi.

If the result in step 601 is false, the flag Fe is set to O in step 607 and the process proceeds to step 606.

If the result in step 600 is false, the flag Fe is set to O in step 608. In step 609, it is determined whether Tea has risen above the current 8-port air temperature Te. If true, in step 610, the temperature difference (Teo
Te) is higher than the upper limit Teom. In step 611, the increased amount is set as a new Teoi.

In step 612, it is determined whether a flag Ft indicating the execution time of the integral process is 1 or not. If true, the flag F+ is set to O in step 613. Step 61
4, the temperature difference (Tea!-Te) is multiplied by the coefficient /T and added to the integral term I+.

In step 615, the integral term I+ is set to an upper limit of 11 ma
If true, step 616
So, L is I 1ma! Replace with In step 617, it is determined whether the integral term 1 is less than the lower limit value I l+aln. If true, in step 618, It is replaced with I 1ain.

In step 619, the temperature difference (T e o t T
a) is multiplied by a coefficient K, and an integral term (2) is added to determine the energizing current I sat of the control valve coil 32.

The details of Ta control will be explained with reference to FIG. Step 7
At 00, it is determined whether the flag F was 1 last time. In step 701, it is determined whether Tduo is higher than the current vent blowout target temperature Tduoi. If true, in step 702, it is determined whether a flag Fd indicating the execution time of the Tduo increase restriction process is 1 or not. Note that the flag Fd is set in the flow TIMER of FIG. 3, which will be described later.

In step 703, the flag F is set to ○, and in step 7
At 04, the temperature difference (Tduo-TdUo is the upper limit Tdu
Determine whether the value exceeds o+a. In step 705, the increase is set as T duom and a new T a u
o i, and in step 706, Tduo is set to a new T
Duoz.

If the result in step 701 is false, the flag Fd is set to O in step 707 and the process proceeds to step 706.

If the result in step 700 is false, the flag F is set to O in step 708. In step 709, it is determined whether Tduo has risen above the current vent blowout temperature TdlI. If true, in step 710, the temperature difference (
It is determined whether T', +uo Tu) is higher than the upper limit T duom. In step 711, the increased amount is set as T duoIl and a new Tauoi.

In step 712, it is determined whether a flag F indicating the execution time of the integral process is 1. If true, the flag F1 is set to 0 in step 713. In step 714, the temperature difference (T duon −T du) is given a coefficient /T
Multiply by and add to the integral term .

In step 715, the integral term
If true, step 716
Then, replace 11 with IimaX. Step 717
Then, it is determined whether the integral term 1 is less than the lower limit value I 1411, and if true, in step 718, II is changed to I
Replace with t+ain.

In step 719, the temperature difference (T, +uor Tdu
) is multiplied by a coefficient K and an integral term is added to determine the energizing current I SQL of the control valve coil 32.

Returning to FIG. 2, the process proceeds to step 108. FIG. 9 shows the details.

In step 800, the necessity of idle stabilization processing is determined based on the detected value Ne of the engine speed sensor 30 based on the characteristics shown. If necessary, flag F is set to 1, and the process proceeds to step 802 after the determination in step 801.

In step 802, the heat load on the evaporator 12 is determined by the product of the inlet air temperature Te and the voltage v1 of the motor 9, and l5oaU is determined depending on whether the compressor 3 is turned on or off. In step 803, step 106 or step 10
It is determined whether I sow determined in step 7 is greater than l5oaU. If true, the magnetic clutch 31 is turned off in step 804, and the I
son is the maximum current Is. 9. Make it x.

In step 806, depending on the heat load of the evaporator 12, I
Find sow L. In step 807, I
Determine whether soc is greater than or equal to I sow L. If true, in step 808, a flag that allows the magnetic clutch 31 to be turned on is stored in the RAM.

In step 809, l5otU is set as I sot,
In step 810, it is determined whether it is possible to turn on the magnetic clutch 31 according to Isoc.

Returning to FIG. 2, the process proceeds to step 109. FIG. 10 shows the details.

In step 900, it is determined whether the determination in step 108 is on or not using a flag stored in the RAM. In step 901, the possibility of freezing is determined based on the temperature difference (Tea!-Te), and in step 902, the process branches depending on the result.

In step 903, the wind speed to be detected by the wind speed sensor 27 is multiplied by a predetermined coefficient (0.6 in this embodiment) according to the characteristics shown in the diagram given in advance by the voltage of the outlet and the motor 9. Wind speed G.

Calculate. In step 904, the presence or absence of freezing is determined based on the wind speed difference (GGJ), and in step 905, the process branches depending on the result.

That is, GJ is a predetermined value determined from the physical quantity V concerning the amount of air blown, and if the detected value G is less than GJ, the compressor is stopped in step 907, which will be described later.

In step 906, the magnetic clutch 31 is turned on and the current of the control valve coil 32 is set to P sat.
Controlled by WM output.

In the compressor 3 of this embodiment, the current I s of the control valve coil 32
The discharge capacity decreases as on increases.

In step 907, the magnetic clutch 31 is turned off, and in step 908, the current of the control valve coil 32 reaches the maximum I.
It is controlled by PWM output so that the satmax is reached.

Next, the TIMER processing will be explained with reference to FIG. In step 150, the execution period of the integral process (in this embodiment,
500 milliseconds)
Count up l. In step 151, the counter C is set to a number Coo corresponding to the execution cycle (in this embodiment,
100=50015). If true, the flag F is set to 1 and the counter C1 is returned to O in step 152.

In step 153, a counter Ca that counts the execution cycle of the Tduo increase restriction process is incremented. In step 154, it is determined whether the counter Cd has reached the number CdO corresponding to the execution cycle. If true, the flag Fd is set to 1 and the counter C4 is returned to 0 in step 155.

In step 156, a counter Ce that counts the execution cycle of the 'reo increase restriction process is incremented. In step 157, it is determined whether the counter C6 has reached the number CEO corresponding to the execution cycle. If true, the flag Fe is set to 1 and the counter Ce is returned to O in step 158.

When the above processing is completed, the process returns to the flow shown in FIG. 2 and restarts the process from the next step where the timer interrupt occurred.

According to this embodiment, freezing of the evaporator can be detected by the wind speed sensor that controls the temperature and air distribution volume of the air blown into the vehicle interior, and it is possible to provide a system with excellent detection accuracy at a low cost. can.

In a second embodiment, in step 101, instead of V m,
The vehicle interior air temperature Tr and the target temperature Ts are received. Then, in step 903, GJ is calculated based on the characteristics shown in FIG. In other words, this is the second invention. As described above, the applied voltage (2) of the motor 9 of the blower 10 is determined by TsTrl, so that substantially the same effect as in the first embodiment can be obtained.

The third embodiment is the clutch control shown in FIG. 10 as shown in FIG. 12, and corresponds to the third invention. Steps 900 to 904 and Step 907
．． Since step 908 remains unchanged, its description will be omitted.

When it is determined in step 905 that the evaporator 12 is frozen due to the wind speed G, in step 909 the control valve coil 3
Let the current I Sol of 2 be the maximum I SOffima. In step 906, the current in the control valve coil is I s
It is controlled by PWM output so that it becomes at.

When the discharge capacity of the compressor 3 becomes approximately 0, the progress of freezing can be stopped in the third embodiment as well, and furthermore, rocking due to engagement and engagement of the clutch 31 can be prevented.

In the fourth embodiment, step 101 is communication with the air conditioning electronic control device 2 using the SCI terminal, and step 90
9, and corresponds to the sixth invention.

The air conditioning electronic control unit 2 is based on the new car manual Infiniti Q45 (G50 series cars, G5
0-1), pages E-62 to E- published October 1989.
It has a self-diagnosis function as described on page 64, and by displaying the received freezing occurrence information, it can assist in repairs in the market.

The fifth embodiment is one in which the clutch control in step 109 in FIG. 2 is changed to the process in FIG. 13, and corresponds to the seventh invention.

In step 950, it is determined whether Te inputted in step 102 is higher than a predetermined value TepC (in this embodiment, 3° C.) and there is no freezing at all.

If true, in step 951, the ratio between the standard wind speed and the detected wind speed G, which is obtained by dividing the voltage V of the motor 9 by the coefficient Rgo, is determined, and the coefficient Rg is determined in step 952, which will be described later.

From step 900 to step 903, the same processing as in FIG. 10 is executed, and in step 952, GI is multiplied by a coefficient R3 for correction, and based on the difference from the detected wind speed G, it is determined whether the magnetic clutch 31 is on or off. .

According to this embodiment, the relationship between the voltage (2) of the motor 9 and the blowing wind speed is calibrated as needed, so that erroneous determination of freezing can be prevented.

〔Effect of the invention〕

According to the present invention, freezing of the evaporator is detected by a wind speed sensor, so dehumidification can be performed without causing the problem of freezing when the intake air temperature is below O''CC, and fogging of window glass can be prevented even at low outside temperatures. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIGS. 2 to 13 are flowcharts for storing information in the microcomputer of FIG. 1. 3... Compressor, 4... Electronic control device for compressor, 9...
- Motor, 12... Evaporator, 27... Wind speed sensor, 3
1...Fugnet clutch, 32...Control valve coil.

Claims (1)

[Claims] 1. An air conditioner for an automobile comprising an air blower, an evaporator that cools the blown air, a compressor that circulates refrigerant to the evaporator, and a control means that connects and connects the compressor and a power source, the air conditioner comprising: an air conditioner downstream of the evaporator; A means for detecting the wind speed of the passing air is provided,
The control means determines a predetermined value of wind speed from the detected physical quantity using a predetermined relationship between an air blowing amount of the blower and a related physical quantity of the blower, and the detected value of the wind speed is set to the predetermined value. If the number of air conditioners is smaller, the air conditioner for an automobile is further provided with means for separating the compressor and the power source.