JPH0749247B2 - Vehicle air conditioner - Google Patents

Description

The present invention relates to a vehicle air conditioner.

(Prior Art) Many recent vehicles are provided with a heating device or an air conditioning device that heats the interior of the vehicle to a comfortable temperature. As warm air for heating is warmed by engine cooling water, the air intake door is switched to the outside air introduction side to introduce cold outside air when the engine speed is low, such as at low speeds and idling. If this is attempted, there is a disadvantage that the heating function is lowered due to the small amount of heat radiation of the heater core and the temperature inside the vehicle compartment is gradually lowered.

Therefore, in order to prevent the heating function from deteriorating even when the outside air is introduced when the engine speed is low, some of the air inside the vehicle, that is, the inside air is introduced so that the intake amount of the inside and outside air is automatically controlled according to the vehicle speed. Is proposed (for example, Japanese Utility Model Publication No. 58-51048).

In this heating device, the air intake duct of the device main body is provided with an opening communicating with the vehicle compartment, and the recirculation door that opens and closes this opening works as a one-way valve. When the ram pressure in the air intake duct is higher than the vehicle interior pressure, the recirculation door is closed to prevent the inside air from entering through the opening, and only the outside air is taken into the heating device body, and the engine speed is low. Alternatively, when idling, that is, when the ram pressure in the air intake duct is smaller than the vehicle interior pressure, the recirculation door is opened by the opening amount exemplifying the differential pressure to circulate warm air in the vehicle interior to enhance the heating effect. ing.

By the way, in such a heating system, when the outside air inlet is blocked by snow during snowfall or snowfall and the ram pressure in the duct section becomes small, the recirculation door opens greatly in proportion to the differential pressure and the warm air inside the vehicle There is a problem that the window glass becomes cloudy due to the moisture contained in the internal air because a large amount of air is inhaled.

(Object and configuration of the invention) The present invention has been made in view of the above points, and excessively introduces warmed inside air through the recirculation door due to introduction of outside air at the entrance of the air duct when snow is accumulated, and thereby the window glass In order to achieve this purpose, when the power consumption of the blower fan motor is above a specified value, close the recirculation door for introducing the inside air provided in the air intake door. Configured to.

(Example) The present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a control circuit for an air conditioner according to the present invention, where 1 is an outside air intake opening at one end of the air conditioner body, 2 is an air intake duct, and 3 is an air intake duct 2. This is an air intake door, and the door 3 is provided with a recirculation door 4 for taking in vehicle interior air (inside air). Reference numeral 5 is an actuator for driving the air intake door 3 so as to switch between the outside air introduction position shown by a solid line and the inside air circulation position shown by a chain line, 6 is an electromagnet for opening and closing the recirculation door 4, and 7 is a blower. A fan, a blower fan motor 8 for rotating the blower fan 7, and an auto amplifier 9 for controlling the rotation of the blower fan motor 8 and the opening / closing of the recirculation door 4 in accordance with the output from the vehicle speed sensor 10 and the position of the fan switch 11. , 12 are evaporators that dehumidify and cool the introduced air by the action of a refrigerant. It should be noted that the other components of the air conditioner are well known in the related art and are not directly related to the present invention, and therefore are omitted.

The operation of the air conditioner will be described.

In the outside air introduction mode, the air intake door 3 is in the outside air introduction position shown by the solid line, and when the fan switch 11 is set to the desired position and the blower fan motor 8 is rotated, the blower fan 7 introduces the outside air from the outside air introduction port 1. Then, the introduced outside air is sent to the evaporator 12, where it is dehumidified and cooled. At this time, the pressure in the upstream space A of the blower fan 7 in the air intake duct 2 decreases due to the resistance of the intake port, so the pressure in the vehicle interior becomes higher and the recirculation door closed by its own weight until then. Due to this pressure difference, 4 opens and the inside air is introduced into the duct 2.

However, if the outside air inlet 1 is blocked due to snow during snowfall,
Since the pressure in the space A in the air intake duct 2 becomes lower than that in the normal state, the difference from the pressure in the vehicle interior becomes large.
On the other hand, in such a state, the resistance when the blower fan 7 sucks the outside air increases, so that the power consumption of the blower fan motor 8 rapidly increases.

Therefore, as shown in the flowchart of FIG. 2, the auto amplifier 9 first determines whether the air introduction mode of the air conditioner is the outside air introduction mode or the inside air introduction mode by using the position of the air intake door 3 or a drive signal to the actuator 5. (F-1), the open / close control of the recirculation door 4 is not necessary in the inside air introduction mode. Therefore, the driving electromagnet 6 of the recirculation door 4 from the auto amplifier 9 is unnecessary.
The drive signal is not output to the door 4 and the door 4 remains open (F-2). However, in the outside air introduction mode, it is determined whether the power consumption of the blower fan motor 8 is equal to or higher than the reference value (F-
3). As a result, when the power consumption of the blower fan motor 8 is equal to or higher than the reference value, it is determined that the outside air inlet 1 is blocked due to snow or the like as described above, and a drive signal is sent to the electromagnet 6 to 6 is excited to close the recirculation door 4 (F-4). As a result, the inside air introduced is eliminated, and the moisture contained in the warm air blown into the vehicle interior is reduced, so that the window glass does not fog.

By the way, when traveling at high speed, the ram pressure is generated even if the outside air inlet is normally opened, and the space A in the air intake duct 2 is
And the pressure difference between the vehicle interior pressure and the vehicle interior pressure increases, and the power consumption of the blower fan motor 8 may increase. In such a case, if the recirculation door 4 is closed by the control operation described above, it is not preferable for the heating effect. Therefore, as shown in FIG. 3, using the vehicle speed information from the vehicle speed sensor 10, it is determined whether or not the vehicle speed is equal to or higher than the reference value based on the output of the vehicle speed sensor (F-5). Determines that the rapid increase in power consumption by the blower fan motor 8 is not due to the blockage of the outside air introduction port 1 but due to high speed running, and the excitation of the electromagnet 6 is not performed.
On the other hand, when the output of the vehicle speed sensor is equal to or lower than the reference value, the vehicle speed is low, so the process proceeds to step (F-4), and the control is corrected so that the recirculation door 4 is closed.

Although the electromagnet 6 is used to open and close the recirculation door 4 in the above embodiment, it goes without saying that other driving means may be used.

(Effects of the Invention) As described above, the present invention has a recirculation door for introducing the inside air in the air intake door that switches the introduction of the inside air and the outside air, and when the outside air is introduced, the pressure in the vehicle interior and the air intake duct In an air conditioner that opens the recirculation door according to the pressure difference with the upstream side of the blower fan to introduce the inside air of the vehicle interior, the power consumption of the blower fan motor when the outside air is introduced is above a specified value. Since the recirculation door is configured to be closed at this time, normally, the heating effect is enhanced by using the outside air and the inside air, and the recirculation door is closed even when the outside air introduction port is blocked by snow or the like. Therefore, it is possible to prevent the window glass from being fogged by sucking a large amount of inside air.

[Brief description of drawings]

FIG. 1 shows an embodiment of a control circuit for an air conditioner according to the present invention,
FIG. 2 is a flowchart explaining the air conditioning control operation, and FIG.
The figure is a flowchart showing only a modified part of the air conditioning control operation. 1 ... Outside air inlet, 2 ... Air intake duct, 3 ...
... Air intake door, 4 ... Recirculation door, 5 ... Actuator, 6 ... Electromagnet, 7 ... Blower fan, 8 ... Blower fan motor, 9 ... Auto amplifier, 10 ... Vehicle speed sensor, 11 ... ... fan switch, 12 ...
… Evaporator

Claims (1)

[Claims] 1. A differential pressure between the pressure in the vehicle interior and the pressure on the upstream side of the blower fan in the air intake duct when the outside air is introduced, and the air intake door for switching the introduction of the inside air and the outside air has a recirculation door for introducing the inside air. In the air conditioner adapted to open the recirculation door to introduce the inside air into the vehicle compartment according to the above, when the power consumption of the blower fan motor is equal to or more than a predetermined value when the outside air is introduced, the recirculation door is closed. A vehicle air conditioner characterized by comprising a control means.