JPS5843816A - Fan motor control circuit in air conditioner of automobile - Google Patents

Abstract

PURPOSE:To make possible to adjust the rate of a fan motor for the temperature difference between the temperature in the car room and a set temperature, by providing means for parallely moving the characteristic curve of the rate of the fan motor for the temperature difference. CONSTITUTION:The temperature difference between the temperature in the car room and a set temperature is detected by a temperature difference detecting circuit 10, and the output thereof is given to a driving circuit 50 via an absolute value circuit 20, a reverting circuit 30, a level adjusting circuit 70 and a slice circuit 40. The fan motor 60 is driven by the driving circit 50, the characteristic curve of the rate of the fan motor for the temperature difference is moved parallely by the level adjusting circuit 70 to adjust the rotational speed of the motor 60.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an air conditioner for an automobile that changes the speed of a fan motor according to the temperature difference between the vehicle interior temperature and a set temperature, and at the same time changes the speed of the fan motor according to the temperature difference at that time. This invention relates to a device that allows the speed of a fan motor to be adjusted.

A block diagram of a conventional automobile air conditioner is shown in FIG. The characteristic curve (E) shown below the fan motor 60 is the characteristic of the temperature difference (electricity) versus the speed of the motor 60, H, M
, L indicate high speed, intermediate speed, and low speed of the motor 60, respectively. The difference in temperature is positive if the vehicle interior temperature is higher than the set temperature (for example, 25-1::-), and negative if it is the opposite. In other words, since the cooling capacity or heating capacity is proportional to the speed of the fan motor and taro 0 (in other words, the air volume), as the temperature difference 1 increases in the positive direction (in other words, the cabin temperature becomes lower than the set temperature). ), it is necessary to increase the speed of the motor 60, and the difference 1i1t
The speed of the motor 60 needs to be increased as the value increases in the negative direction. On the other hand, if the difference 1 is 0 or close to 0, the motor 60 may be operated at a low speed.

In order to obtain this characteristic curve (E), K first converts the vehicle interior temperature and the set temperature into voltages, and uses the temperature difference detection circuit 10 to obtain a characteristic curve (A) of the voltage with respect to the temperature difference. This characteristic curve (A) is converted into an absolute value by an absolute value circuit 20 to obtain a characteristic surface 11J (B). Also, the inverting circuit 30. The slice circuit 40 inverts the characteristic surface -(B) to the characteristic surface 11i! (Q), sliced is the characteristic side! l (D). The sliced here is
This is because the differential temperature type rotates the motor 6o at a low speed with a certain width such as 0:I'' or near 0.

The second version is a concrete description of the block diagram shown in Figure 1.
It is a circuit diagram shown in a figure. The resistor 11 is a variable resistor that determines a set temperature, and the thermistor 12 is an element that detects the temperature inside the vehicle. In the figure, it is shown for convenience that the temperature difference t is detected by a bridge circuit including the resistor 11, but in reality, the temperature difference type is detected by a circuit including the operational amplifier 21.

Further, in the inverting circuit 30, the characteristic curve (B
) is inverted, and in the slice circuit 4o, a Zener diode, a - node 41 and a resistor 42 are connected via a diode 43.
The characteristic curve is sliced by Further, the current is amplified by the transistor 51, and the transistor 52 changes the voltage applied to the motor 6o to change the speed of the motor 60.

However, the devices shown in FIGS. 1 and 2 have a characteristic curve (E
), once the temperature difference 1 is determined, the speed of the fan motor 60 at that time (ie, the air volume) is uniquely determined. Therefore, under certain temperature conditions, even if you try to perform rapid cooling or heating, you will not be able to rotate the motor 60 faster than the specified speed, and even if you try to reduce the sound of the motor 60, it will rotate slower than the specified speed. motor 6
Could not rotate 0. Of course, it is possible to set the motor 60 to high or low speed by manual adjustment, but in that case, the manually adjusted speed is always maintained, so there is no chance that the room temperature will drop too much beyond the set temperature. 1. Otherwise, it will take an extremely long time to reach the set temperature. The reason for this is that in the case of manual adjustment, the fan motor 6 o''co speed control according to the temperature difference 1 is not automatically performed.

Therefore, the present invention changes the speed of the fan motor according to the temperature difference between the vehicle interior temperature and the set temperature, and at the same time adjusts the speed of the fan motor according to the temperature difference at that time. Means is provided for translating the characteristic curve of temperature difference versus fan motor speed.

The present invention will be described in detail below based on embodiments shown in the accompanying drawings. Note that the same members are given the same reference numerals. FIG. 3 is a block diagram showing one embodiment of the present invention. In the figure, the temperature difference detection circuit 10, the absolute value circuit, and the inversion (b) path 30 are the same as in FIG. However, the level of the output of the inversion circuit 30 is changed by the level adjustment circuit 70, and in this case,
For example, as shown in the characteristic curve (F), the voltage increases with respect to the temperature difference at that time. Next, a voltage equal to or higher than a predetermined voltage is sliced by the slicing circuit 40, and the motor 60 rotates at a speed based on this state. Characteristics! 1 (H) shows the speed characteristics of the motor 60 for the differential temperature type. Therefore, in the above case, even with the same temperature difference (for example, -11), the speed of the motor 60 will be lower than in the case of FIG. 1. This state is shown in detail in FIG. Level adjustment circuit 7
By adjusting 0, the rotation of the motor 60 can be made faster than the conventional one even with the same temperature difference (indicated by a chain -S in FIG. 5). Of course, even in the case of the broken line in Figure 5,
Even in the case of the dashed-dotted line, if the temperature difference changes, the speed of the motor 60 changes accordingly, so as the room temperature approaches the set temperature, the rotational speed of the motor 60 becomes slower.

Incidentally, since the speed of the motor 60 and the air volume are proportional, the vertical axis in FIG. 5 shows the air volume. Furthermore, since the mix door, which determines the distribution of hot air and cold air, changes depending on the temperature difference, the horizontal axis in FIG. 5 also shows the opening degree of the mix door.

FIG. 4 is a circuit diagram specifically showing the third illustrated embodiment. Here, by changing the value of the variable resistor 71, the non-inverting input of the operational amplifier 32 is changed to perform level adjustment. Therefore, in FIG. 4, only the variable resistor 71 is surrounded by a broken line as the level adjustment circuit 70, but in reality, the level adjustment (b) is 1% 70 including the operational amplifier 32. Further, as a method of changing the level, another circuit element may be changed.

As described above, the present invention moves the characteristic curve of temperature difference versus fan/motor speed in parallel, so that the fan/motor speed automatically changes according to the temperature difference, and at the same time, the temperature difference at that time changes. The speed of the fan motor can also be adjusted. Therefore, it can provide heating and cooling effects faster than ordinary automatic air conditioners, can reduce motor noise, and has the effect of automatically reaching the set temperature without the need for subsequent manual adjustments.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a conventional device, Fig. 2 is a circuit diagram specifically showing Fig. 1; Fig. 3 is a block diagram showing an embodiment of the present invention; FIG. 4 is a circuit diagram showing the above embodiment in more detail, and FIG. 5 is a characteristic diagram of the above embodiment. 10... Temperature difference detection circuit, 11... Variable resistor for adjusting set temperature, 12... Thermistor for room temperature detection, 2o...
Absolute value circuit, 30... Inversion circuit, 4o... Slice circuit, 60... Fan motor, 70... Level adjustment circuit.

Claims (1)

[Claims] In an automobile air conditioner comprising means for detecting a temperature difference between a vehicle interior temperature and a set temperature, and means for increasing the speed of the 7 am motor as the absolute value of the temperature difference increases, 1. A control circuit for a 7-amp motor in an automotive air conditioner, characterized in that the circuit is provided with means for parallelly moving the characteristic curve of the speed of the vehicle.