JP3021615B2 - Vehicle air conditioner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an air conditioner for a vehicle, and more particularly to an air conditioner configured to switch an air-conditioning air introduction mode in accordance with a gas concentration of outside air.

(Prior art)

2. Description of the Related Art In general, vehicles such as automobiles are provided with an air conditioner for maintaining a proper temperature and humidity in a passenger compartment to improve comfort and remove fogging of a front window to secure a good view.

Usually, the air conditioner according to the state of the vehicle interior such as a differential mode in which warm air is blown out from a defroster outlet, a heat mode in which warm air is blown out from a heat outlet, and a vent mode in which cool air is blown out from a vent outlet. In addition to being configured so that multiple modes can be selected, the air-conditioning air introduction mode can be selected between an inside air introduction mode that circulates inside air in the vehicle cabin and an outside air introduction mode that introduces external air. It is configured.

On the other hand, Japanese Unexamined Patent Publication No. 62-292521 discloses that a large amount of exhaust gas from a preceding truck or bus or exhaust gas filled in a tunnel is prevented from entering a passenger compartment and causing discomfort to passengers. Therefore, a sensor for detecting the concentration of gas contained in the outside air is provided, and when the gas concentration of the outside air is equal to or higher than a predetermined threshold, the outside air introduction mode is forcibly switched to the inside air introduction mode, and the exhaust gas An air conditioner configured to prevent entry into a room is described.

[Problems to be solved by the invention]

In the air conditioner described in the above-mentioned publication, when the gas concentration of the outside air increases, the air-conditioning air introduction mode is switched to the inside air introduction mode, so that a large amount of exhaust gas and the like can be prevented from entering the vehicle interior. Is set irrespective of the blower output, so if the blower output is high, the amount of air blown is large, so a large amount of exhaust gas etc. will enter the passenger compartment before switching to the inside air introduction mode, There is a problem of giving the occupant a discomfort.

On the other hand, by setting the threshold value low, it is possible to suppress the intrusion of exhaust gas into the vehicle compartment even when the blower output is high, but in this case, even if the gas concentration is slight, the mode is forcibly switched to the inside air introduction mode, There arises a problem that regular air-conditioning control becomes difficult and the passengers feel uncomfortable.

An object of the present invention is to provide a vehicle air conditioner that can effectively prevent exhaust gas and the like from entering a vehicle interior while making the most of normal air conditioning control.

[Means for solving the problem]

According to a first aspect of the present invention, there is provided an air conditioner for a vehicle, comprising: a mode switching unit that selectively switches an air introduction mode between an outside air introduction mode and an inside air introduction mode; a detection unit that detects a gas concentration of outside air; Control means for controlling the mode switching means so as to switch from the outside air introduction mode to the inside air introduction mode when the gas concentration of the outside air exceeds a predetermined threshold value in response to the output from the means. At
Blower output detection means for detecting the blower output of the blower blowing into the vehicle interior is provided, and receives the output from the blower output detection means and sets a gas concentration threshold for switching from the outside air introduction mode to the inside air introduction mode to a blower output. Is set to a first threshold value when is less than a predetermined reference value, and is set to a second threshold value smaller than the first threshold value when the value is equal to or greater than the reference value, so that the switching timing is advanced and the inside air introduction mode is changed. A switching timing changing means for setting a threshold value of the gas concentration for switching to the outside air introduction mode to a third threshold value smaller than the second threshold value is provided.

[Action]

In the vehicle air conditioner according to the first aspect, when the control means receives an output from the detection means for detecting the gas concentration of the outside air and the gas concentration of the outside air becomes equal to or higher than a predetermined threshold value, the mode switching is performed. By controlling the means, the air-conditioning air introduction mode is switched from the outside air introduction mode to the inside air introduction mode. Before switching to the inside air introduction mode, the switching timing changing means detects the blower output detected by the blower output detection means. When the blower output is equal to or higher than the predetermined reference value, the threshold value of the gas concentration is set to the second threshold value smaller than the first threshold value, and the control unit switches to the inside air introduction mode. Can be earlier than the switching timing when it is less than the reference value. When the blower output is less than a predetermined reference value, it is possible to prevent the exhaust gas and the like from entering the vehicle interior while executing the normal air conditioning control as much as possible. As a result, a large amount of exhaust gas can be effectively prevented from entering the vehicle interior.

Further, the switching timing changing means sets the gas concentration threshold for switching from the inside air introduction mode to the outside air introduction mode to a third threshold smaller than the second threshold.
Frequent switching of the introduction mode due to a slight change in the gas concentration near the first and second thresholds can be prevented. The switching timing can be set by effectively utilizing one detecting means, and the threshold value can be changed in a plurality of steps according to the blower output, so that the air-conditioning air introduction mode can be more finely switched.

〔The invention's effect〕

According to the vehicle air conditioner of the first aspect, when the blower output is less than the predetermined reference value, the gas for switching from the outside air introduction mode to the inside air introduction mode, as described in detail in the section of [Action]. By setting the concentration threshold value to the first threshold value, it is possible to prevent exhaust gas and the like from entering the vehicle interior while executing the normal air conditioning control as much as possible, and when the blower output exceeds a predetermined reference value. The threshold value of the gas concentration for switching from the inside air introduction mode to the outside air introduction mode is set to a second threshold value smaller than the first threshold value, so that the switching timing is advanced so that a large amount of exhaust gas or the like enters the vehicle interior. Intrusion can be effectively prevented. Further, the threshold value of the gas concentration for switching from the inside air introduction mode to the outside air introduction mode is set to a third value smaller than the second threshold value.
Since the threshold value is set, it is possible to prevent the introduction mode from being frequently switched due to a slight change in the gas concentration near the first and second threshold values. In addition, the switching timing can be set by effectively utilizing one detecting means, and the threshold value can be changed in a plurality of steps according to the blower output, so that the air-conditioning air introduction mode can be easily switched more finely.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 1, an air conditioner 1 for an automobile includes an air conditioning unit 5 in which a blower fan 2, an evaporator 3, a heater core 4 and the like are unitized, a unit duct 6 as a casing of the air conditioning unit 5, and a unit duct 6. An extended main duct 7 and a differential duct 8 are provided. A plurality of vent outlets 9 are provided at a downstream end of the main duct 7, a defroster outlet 10 is provided at an intermediate portion of the differential duct 8, and a heat duct is provided at the unit duct 6. An air outlet 11 is provided, and the unit duct 6 near the suction portion of the blower fan 2 is provided.
Is provided with an inside air inlet 12 and an outside air inlet 13. The air conditioning unit 5 has an inside air inlet 12 and an outside air inlet.
Inside / outside air switching damper 14 that opens one of the 13 and closes the other
An air mix damper 15 provided in a passage on the upstream side of the heat core 4, a sub damper 16 provided in a passage on the downstream side of the heater core 4, a vent damper 17 provided in an upstream portion of the main duct 7, and a differential duct 8 And a heat damper 19 provided in a passage on the upstream side of the heat outlet 11 and an inside / outside air switching damper.
14 is selectively opened and closed by an actuator 20, the vent damper 17, the differential 18 and the heat damper 19 are respectively adjusted by an actuator 21 to adjust the opening degree, and the air mix damper 15 and the sub damper 16 are respectively linked by an actuator 22. The opening is adjusted.

The air conditioner 1 includes an evaporator 3 and a compressor.
A refrigeration cycle including a compressor 23, a condenser 24, and an expansion valve 25 is provided.
Is connected to the output shaft 27 of the engine E through the evaporator 3 and the refrigerant is circulated through the circulation pipe 28.
Is cooled.

The control unit 30 of the air conditioner 1
As shown in the figure, a start switch 31 of the air conditioner 1 and a mode selection switch 32 for selecting an air-conditioning air outlet 9, 10, 11, such as a vent mode, a heater mode, or a differential mode.
And an inside / outside air changeover switch 33 for selectively switching between an inside air introduction mode for introducing air in the vehicle interior as air-conditioning air and an outside air introduction mode for introducing external air, and automatically targeting the temperature in the interior of the vehicle An auto mode switch 34 for adjusting to the set temperature, and one stage from the minimum air flow to the maximum
An air volume setting switch 35 for switching the blower output to four stages up to the first stage, switches such as a temperature setting volume 36 are connected, and a gas sensor 41 provided near the condenser 24 at the front of the vehicle body, and an inside air temperature sensor 42 , An outside air temperature sensor 43, a temperature sensor 44 attached to an outlet of the evaporator 3, an engine water temperature sensor 45, an insolation sensor 46, and the like. Further, the actuators 20, 21, 22, the fan motor 2a of the blower fan 2 and the pulley 26 electromagnetic clutches are connected respectively.

FIG. ₂ shows that the gas sensor 41 changes its resistance value according to the gas concentration in an atmosphere containing a combustible (reducing) gas such as H ₂ , CO, NOx, etc., and the resistance value decreases as the gas concentration increases. The characteristics are as shown in FIG. The above resistance value is determined by the control unit 30 and the gas sensor 41.
Is applied by applying a predetermined voltage of, for example, 12 V to one of the terminals, and detecting a voltage or current input from the other terminal.

The control unit 30 is mainly composed of a microcomputer, and includes other necessary A / D converters, drive circuits for the actuators 20, 21 and 22, drive circuits for the fan motor 2a, and electromagnetic clutches. The ROM includes a drive circuit and the like. The ROM has a control program for automatic air conditioning control for automatically controlling the air conditioner 1 when the auto mode is selected, and an internal and external program executed as an interrupt process during execution of the control program. A control program for the air switching control, a map for calculating the gas concentration based on the resistance value of the gas sensor 41, and the like are input and stored in advance.

The automatic air-conditioning control is based on the detection outputs from the temperature sensors 42 to 45 and the solar radiation amount sensor 46, switching the opening degree of the air mix damper 15 and the fan output, introducing the air-conditioning air inlets 12 and 13 and the air outlet 9. 10/11 switching and compressor 23 ON / OFF
The existing well-known configuration that drives the actuators 20, 21 and 22 and drives the electromagnetic clutch to automatically control the temperature in the passenger compartment to the target set temperature set by the temperature setting volume 36 belongs to.

By the way, in the automatic air-conditioning control, the outside air introduction mode is usually selected except when the passenger compartment is rapidly cooled, so that when traveling behind a truck or a bus or traveling in a tunnel, a large amount of exhaust gas is air-conditioned. It is introduced into the vehicle interior via the device 1. In particular, when the blower output is high and the air volume is large, a large amount of outside air is introduced into the vehicle interior, so that the gas concentration in the vehicle interior rapidly increases.

The air conditioner 1 of the present application is provided with a gas sensor 41 for detecting the gas concentration of the outside air, and when the gas concentration obtained from the resistance value of the gas sensor 41 becomes equal to or higher than a predetermined threshold, the outside air introduction mode is changed to the inside air introduction mode. In addition to the switching, when the blower output is three or more stages, by changing the predetermined threshold value to a small value, the switching timing to the inside air introduction mode is advanced so that the intrusion of exhaust gas or the like into the vehicle compartment is prevented. It was made.

Next, the inside / outside air switching control will be described with reference to a flowchart shown in FIG. In the figure, Si (i
= 1, 2, 3,...) Is each step.

When the start switch 31 of the air conditioner 1 is turned on and the auto mode switch 34 is operated, the automatic air conditioning control is started. Then, when the inside / outside air switching control is started as an interruption process of the automatic air conditioning control, the resistance value of the gas sensor 41 is read, and the current number B of blower fans 2 set in the automatic air conditioning control and the air conditioning air. The introduction mode is read (S1), and the gas concentration G of the outside air is obtained from the resistance value of the gas sensor 41 (S2).

Next, it is determined whether or not the air-conditioning air introduction mode is the outside air introduction mode (S3). In the case of the outside air introduction mode, it is determined whether or not the number B of the blower fans 2 is three or more (S4).
In the case of one or two stages, the threshold value α is set to the standard value St (S5). In the case of three or four stages, the threshold value α is set.
Is set to a value Lo smaller than the standard value St (S6).

Next, it is determined whether or not the gas concentration G of the outside air is equal to or higher than the threshold value α (S7). If No, the process returns to the automatic air-conditioning control. ,
The inside / outside air switching damper 14 closes the outside air inlet 13 and opens the inside air inlet 12, sets the flag F (S9), and returns to the automatic air conditioning control. In other words, when entering a tunnel with poor ventilation, or when the gas concentration of the outside air becomes high at the time of starting a preceding truck or bus, the mode is switched from the outside air introduction mode to the inside air introduction mode, and the exhaust gas or the like is introduced into the vehicle interior. Intrusion is prevented. Moreover, as shown in FIG.
If the number of stages B of the blower fan 2 is set to one or two and the amount of air-conditioning air introduced is relatively small, the threshold α
Is set to the standard value St, so that the introduction mode is not frequently switched due to a slight change in the gas concentration,
When the number of stages B of the blower fan 2 is set to three or four and the amount of air-conditioning air introduced is relatively large, the threshold α is set to a value Lo smaller than the standard value St, The switching timing of the introduction mode is earlier than in the case where the standard St is set to the threshold α, and the intrusion of the exhaust gas into the vehicle compartment is effectively prevented.

On the other hand, if No is determined in S3, that is, if the inside air introduction mode is selected, it is determined whether or not the flag F is set (S10), to prevent the intrusion of exhaust gas. If the shy air introduction mode is selected
If the determination is Yes, the process proceeds to S11, and if the inside air is circulated for performing rapid cooling or the like, the determination is No and the process returns to the automatic air conditioning control.

In S11, it is determined whether or not the gas concentration G of the outside air is equal to or lower than a predetermined threshold value β. When the gas concentration G of the outside air becomes equal to or lower than the predetermined threshold value β through a tunnel or the like, the outside air introduction mode is set. (S12), the flag F is reset (S1).
3) If the gas concentration of the outside air is still higher than the threshold value β, for example, while traveling in a tunnel, the process returns to the automatic air conditioning control in the inside air introduction mode. The threshold value α is set to be larger than the threshold value β, and it is possible to prevent the introduction mode from being frequently switched due to a slight change in the gas concentration G near the threshold value α.

As described above, according to the air conditioner 1 according to the embodiment, by switching the threshold α between the case where the blower output is high and the case where the blower output is low, the normal air conditioning is performed when the blower output is less than three stages. While controlling as much as possible, it is possible to prevent exhaust gas from entering the vehicle interior. If the blower output is three or more stages, the switching timing is advanced to effectively infiltrate a large amount of exhaust gas into the vehicle interior. Can be prevented. In addition, it is possible to switch the air-conditioning air introduction mode by effectively utilizing one gas sensor 41.

In this embodiment, the inside / outside air switching control is executed as the interrupt processing of the automatic air conditioning control.
Even when the outside air introduction mode is set by the above operation, when the gas concentration of the outside air becomes high, the air conditioning air introduction mode may be switched in the same manner as described above.

In this embodiment, the inside / outside air switching timing is set based on the output of one gas sensor 41. However, the switching timing may be set using the outputs of two gas sensors having different sensitivities.

In the present embodiment, the present invention is applied to an air conditioner capable of switching the amount of air flow to four stages. However, the present invention can be applied to an air conditioner capable of four or more stages or stepless adjustment. .

[Brief description of the drawings]

The drawings show an embodiment of the present invention. FIG. 1 is an overall configuration diagram of an air conditioner, FIG. 2 is a characteristic diagram of a gas sensor, FIG. 3 is a flowchart of a routine for switching between inside and outside air, and FIG. It is a time chart which shows an air switching timing. DESCRIPTION OF SYMBOLS 1 ... Air-conditioning device, 2 ... Blower fan, 12 ... Inside air inlet, 13 ... Outside air inlet, 14 ... Inside / outside air switching damper, 20 ...
... Actuator, 30 ... Control unit, 33 ...
… Inside / outside air changeover switch, 41 …… Gas sensor.

Claims (1)

(57) [Claims] 1. A mode switching means for selectively switching an air-conditioning air introduction mode between an outside air introduction mode and an inside air introduction mode, a detection means for detecting a gas concentration of outside air, and receiving an output from the detection means. A vehicle air conditioner having control means for controlling a mode switching means so as to switch from the outside air introduction mode to the inside air introduction mode when the gas concentration of the outside air exceeds a predetermined threshold value. Blower output detection means for detecting the blower output of the blower is provided. Upon receiving the output from the blower output detection means, a threshold value of the gas concentration for switching from the outside air introduction mode to the inside air introduction mode is set to a predetermined reference value. If it is less than the reference value, it is set to a first threshold value, and if it is not less than the reference value, it is set to a second threshold value smaller than the first threshold value to accelerate the switching timing and The threshold of gas concentration to switch from the inside air intake mode to the outside air introduction mode, air conditioning system, characterized in that a switching timing changing means than the second threshold value is set to a third threshold value.