Air flow control apparatus in an air conditioner

An air conditioner comprises a heat exchanger for conducting refrigerant in heat exchanging relationship with an air flow, and a blower for drawing air through the heat exchanger. An adjustable flow distributing plate is disposed between the heat exchanger and blower and is movable by a motor to various positions for controlling the relative air flows through respective portions of the heat exchanger. Temperature sensors are connected to the heat exchanger for detecting the refrigerant temperature at various regions of the heat exchanger. The adjustable plate is positioned in a desired position in response to the detected refrigerant temperatures for equalizing the refrigerant temperatures in the regions of the heat exchanger.

TECHNICAL FIELD 
The invention is related to providing an air flow control apparatus and 
method for an air conditioner, and in particular, to providing an air flow 
control apparatus and method in an air conditioner for varying the air 
flow at the outlet side of the refrigerant of a heat-exchanger. 
PRIOR ART 
The indoor unit of a conventional multi-unit air-conditioner includes a 
blower fan and a heat-exchanger which are usually often placed at an 
irregular interval from each other. In other words, when air passes 
through the heat-exchanger, the air flow rate through the portion near the 
fan motor (the upper portion of the heat-exchanger) is greater than the 
air flow rate through another portion farther away from the fan motor (the 
lower portion of the heat-exchanger). This causes the heat-exchange 
function to be performed in an inconsistent manner throughout the 
heat-exchanger, whereby the heat-exchanging efficiency is decreased to a 
large degree and the cooling capability is significantly reduced. 
In order to resolve these problems, a typical example is Japan Laid-Open 
Utility Model No. Sho 57-153916 as shown in FIG. 5. The indoor unit 
comprises a housing 51, a blower fan 52, a heat-exchange coil 53, a drain 
pan 54, an air flow passage 50, an air flow directing and noise 
suppressing piece 56, an air flow directing and noise suppressing plate 57 
and a supporting shaft 58. The air flow directing and noise suppressing 
piece 56 installed at an intermediate portion of the air flow passage 50 
to enable its angle, direction and position to be freely changed and 
adjusted, and the air flow directing and noise suppressing plate 57 is 
shaped like a curved mountain ridge and is mounted at the rear wall of the 
unit housing so that it can be freely moved upward and downward, thereby 
adjusting the air current direction and the air flow rate from the blower 
52. 
The utility model discloses that the air current and the air flow rate from 
the blower 52 to the heat-exchanger 53 are adjusted by the air flow 
directing and noise suppressing piece 56 and the air flow directing and 
noise suppressing plate 57, but it fails to adjust the air current and the 
air flow rate in accordance with the temperature at any portion of the 
heat-exchanger 53, and thus the air flow rate passing through the 
heat-exchanger 53 cannot be uniformly controlled. 
Accordingly, it is an object of the invention to provide an apparatus and 
method for automatically controlling the air current and the air flow rate 
passing through any portion of the heat-exchanger 53. 
Another object of the invention is to provide an apparatus and method for 
varying an air flow passage in accordance with the temperatures of the 
refrigerant detected at each portion of the heat-exchanger. 
Another object of the invention is to provide an apparatus and method for 
uniformly the heat-exchanging the air at every portion of the 
heat-exchanger. 
SUMMARY OF THE INVENTION 
In order to accomplish these objects, an air flow control apparatus of the 
invention comprises a plurality of sensors mounted on the heat-exchanger 
to detect the temperature of the refrigerant, an air separating plate 
mounted on the lower portion of the air blowing apparatus which intakes 
and discharges cooled air from the heat-exchanger and for varying the air 
flow, a control portion for receiving temperature data from the sensors 
and processing the temperature data to transmit a control signal and a 
step motor portion for rotating the air separating plate in accordance 
with the control signal. 
Also, an air flow control method of the invention comprises steps of: 
setting the air separating plate at the initial position, detecting the 
temperature of the refrigerant at various portions of the heat-exchanger, 
calculating the average value of the detected temperatures corresponding 
to the upper portion and lower portion of the heat-exchanger, comparing 
these two average values with each other and controlling the air 
separating plate in order to control the air flow in accordance with the 
comparison result.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1A and 1B respectively show a longitudinal cross-sectional view and a 
front view of an indoor unit of an air-conditioner according to the 
invention. 
An indoor unit 1 includes a heat-exchanger 2 for exchanging heat with the 
intake air. A fan motor 3 is electrically connected to a power source so 
that it can be rotated. A blowing apparatus 4 is attached by a shaft to 
the fan motor 3 to be rotated by the driving force thereof, so that intake 
air from inlets 4A and 4B of the fan housing is discharged into the indoor 
living space through an outlet 9 and a duct 11. 
A plurality of sensors 6A to 6D air are fixed at predetermined positions in 
the heat-exchanger 2 at the discharging side of the air flow in order to 
detect the temperature of the refrigerant. The sensors are arranged at 
equal intervals whereby the temperature sensor 6A is located on the upper 
portion of the heat-exchanger 2, and the temperature sensor 6D is located 
on the lower portion of the heat-exchanger 2. The arrangement of the 
temperature sensors cannot limit the scope of the invention because the 
diagonal arrangement or other patterns can be utilized, if necessary. 
An air separating or distributing plate 7 is mounted to the lower portion 
of a step motor 5 to vary the air flow passing heat-exchanged air. The 
step motor 5 receives a control signal from a microprocessor 25 (as 
illustrated in FIG. 2) to rotate the air separating plate 7 upwards or 
downwards. 
FIG. 2 is a schematic block diagram of an air flow control apparatus 
according to the invention to which the invention is applied. 
The microprocessor 25 includes an operation signal inputting portion 21 for 
inputting instruction signals for the operation of the air-conditioner, a 
room temperature detecting portion 22 for detecting the room temperature 
during the operation of the air-conditioner, an outdoor temperature 
detecting portion 23 for detecting the outdoor temperature during the 
operation of the air-conditioner, a refrigerant temperature detecting 
portion 24 including the plurality of sensors 6A to 6D mounted at 
predetermined positions to detect the temperature of the refrigerant 
during the operation of the air-conditioner. Thus, the microprocessor 25 
receives signals from the operation signal inputting portion 21, the room 
temperature detecting portion 22, the outdoor temperature detecting 
portion 23, and the refrigerant temperature detecting portion 24 and then 
processes those signals according to the system programming and then 
outputs control signals to its peripheral apparatus. For example, a 
compressor operating portion 26 control the operation of a compressor 
according to the control signals. A step motor operating portion 27 
rotates the air separating plate 7 so as to vary the air flow according to 
the control signals. A fan motor operating portion 28 controls the 
operation of the fan motor 3 constituted as a part of an air circulating 
apparatus according to the control signals. 
FIG. 3 shows the operational states of the air separating plate 7 according 
to an air flow control apparatus and method of the invention. 
As shown in FIG. 3, the air separating plate 7 varies the air flow by being 
rotated with reference to the initial fixing position PB. In other words, 
the air flow current direction and the flow rate are altered to positions 
depicted in FIGS. 3B-3F. 
Therefore, the air flow passage control will be described as follows: 
The indoor unit 1 is provided with the heat-exchanger 2, for example an 
evaporator, constituted as a part of the cooling cycle system, and an 
associated control apparatus (omitted from the drawing) properly installed 
therein. The indoor unit 1 is installed in the living space to draw in and 
discharge air, in a manner that the heat-exchanger 2 exchanges heat with 
the air drawn in through air inlet portion 8 which is formed in the lower 
portion of the indoor unit 1. Each of the refrigerant temperature sensors 
6A to 6D, arranged at equal intervals on the discharging surface of the 
heat-exchanger 2 detects the refrigerant temperature and this data is then 
transmitted to the microprocessor 25. The microprocessor 25 processes the 
detected temperature signals to control the rotation of the air separating 
plate 7 so as to vary the air flow as shown in FIG. 3A-3F. 
In accordance with the formulas shown below, the microprocessor 25 
calculates the average value T.sub.1 of the temperatures T.sub.A and 
T.sub.B detected by the refrigerant temperature sensors 6A and 6B and the 
average value T.sub.2 of the temperatures T.sub.C and T.sub.D detected by 
the refrigerant temperature sensors 6C and 6D, compares the two average 
values to each other and then determines the rotation angle of the air 
separating plate 7. 
EQU T.sub.1 =T.sub.A +T.sub.B /2, T.sub.2 =T.sub.C +T.sub.D /2 
The microprocessor 25 transmits a control signal corresponding to the 
rotation angle of the air separating plate 7 to the step motor operating 
portion 27, thereby operating the step motor 5 and rotating the air 
separating plate 7. 
The air blowing apparatus 4 includes the fan motor and air suction inlets 
4A and 4B formed on the left and right sides of its housing, said housing 
mounted in the middle portion of the indoor unit. Therefore, the rotation 
of the air blowing fan 10 connected to the fan motor under the control of 
the microprocessor 25 introduces air through the heat-exchanger 2 into the 
air blowing apparatus 4 through the air suction inlets 4A and 4B. The air 
blowing apparatus 4 discharges air through duct 11 and the air outlet 9 
into the living space. 
FIG. 4 is a flow chart illustrating an air flow control method of the 
invention. 
When the power source is applied to the air conditioner, the microprocessor 
25 performs an initial process which is common in most air-conditioners. 
Thus, an explanation of the process is omitted herein because it is not 
the invention. The air separating plate 7 is vertically fixed at the 
initial position as shown in FIG. 1 and FIG. 3A and 3E. 
The microprocessor 25 receives the equipment operator's instruction signals 
for the operation of the air conditioner from an operation signal 
inputting portion 21. Also, the microprocessor 25 processes the input 
signals and the temperature signals obtained from room temperature 
detecting portion 22 and outdoor temperature detecting portion 23 
according to the system program and transmits the control signals to 
compressor operating portion 26 and fan motor operating portion 28, so 
that a compressor (not shown) and the air blowing apparatus 4 are operated 
to enable the indoor unit 1 to air-condition the living space. 
At this time, air passing through the portion of the heat-exchanger 2 
located near the air blowing apparatus 4 is rapidly discharged, while air 
passing through the portion of the heat-exchanger located distant from the 
blowing apparatus 4 is discharged at a relatively slower speed. This 
causes differences in the amount of heat-exchanged at each part of the 
heat-exchanger 2. Thus, the temperature of the portion generating a 
relatively larger amount of heat-exchanged air is higher than that of the 
portion generating a relatively smaller amount of heat-exchanged air. 
Accordingly, step 30 is performed in a manner whereby the air separating 
plate 7 is vertically disposed. The four temperature sensors 6A to 6D are 
electrically connected to the refrigerant temperature detecting portion 24 
to detect the refrigerant temperatures at predetermined portions of the 
heat-exchanger 2 during its operation to enable the refrigerant 
temperature detecting portion 24 to supply the detected temperature 
signals to the microprocessor 25. 
Step 30 proceeds to step 31 in order to cause the microprocessor 25 to 
calculate the average temperature value (T.sub.1 =T.sub.A +T.sub.B /2) of 
the upper portion of the heat-exchanger and the average temperature value 
(T.sub.2 =T.sub.C +T.sub.D /2) of the lower portion thereof by the 
refrigerant temperature sensors 6A and 6B and the refrigerant temperature 
sensors 6C and 6D, respectively. 
Step 31 proceeds to step 32 to determine whether the average temperature 
values T.sub.1 and T.sub.2 are equal to each other. If the average 
temperature values T.sub.1 and T.sub.2 are equal to each other, the 
microprocessor 25 calculates the uniform refrigerant temperature 
distribution at the predetermined portions of the heat-exchanger 2 and 
does not attempt the change of the air flow rate and the air flow current. 
The system control proceeds to step 33, leaving the air separating plate 7 
fixed at the vertical position PB as shown in FIG. 1 and FIG. 3A and 3E. 
Conversely, if the average temperature values T.sub.1 and T.sub.2 are not 
equal to each other, step 32 proceeds to step 34 to determine whether the 
average temperature value T.sub.2 of the lower heat-exchanger portion is 
larger than the average temperature value T.sub.1 of the upper 
heat-exchanger portion. If the lower portion's average temperature value 
T.sub.2 is larger than the upper portion's average temperature value 
T.sub.1, this refrigerant temperature distribution in the heat-exchanger 2 
means that the upper portion has a smaller flow rate of heat-exchanged air 
than the lower portion. Therefore, in order to increase the air flow rate 
passing through the upper portion, step 34 goes to step 35 in order to 
rotate the air separating plate 7 upward by a step from the initial 
vertical position PB as shown in FIG. 3D. 
Next, at step 36, the microprocessor 25 receives the current refrigerant 
temperature signals detected by the four temperature sensors 6A to 6D of 
the refrigerant temperature detecting portion 24 to determine whether the 
upper and lower average temperature values T.sub.1 and T.sub.2 are equal 
to each other. If the average temperature values T.sub.1 and T.sub.2 are 
not equal to each other, step 35 is repeated to rotate the air separating 
plate 7 upward by another step (FIG. 3C), and so on, until the upper and 
lower average temperature values, T.sub.1 and T.sub.2 respectively, are 
the same. 
Subsequently, if at step 36 the average temperature values T.sub.1 and 
T.sub.2 are equal to each other, the system control proceeds to step 33 
whereby the air separating plate 7 is fixed at the vertical position PB. 
If, the step 34, T.sub.2 is not greater than T.sub.1, then the operation 
proceeds to steps 37 and 38 where the plate 7 is rotated toward position 
PC (by plural steps if necessary). 
As described above, the invention enables a heat-exchanger to heat-exchange 
air at numerous portions, thereby improving the operating efficiency of 
the heat-exchanger and increasing the air-conditioning efficiency. 
The invention describes the arrangement of a plurality of temperature 
sensors in the up and down directions, but it is noted that a diagonal and 
longitudinal arrangement of sensors falls within the scope of the 
invention.