JP3465352B2 - Vehicle air conditioner - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular air conditioner capable of automatically switching the inside / outside air switching mode in accordance with the degree of dirt outside the vehicle compartment.

[0002]

2. Description of the Related Art For example, as disclosed in Japanese Patent Laid-Open No. 186513/1982, the degree of dirt outside the vehicle compartment is detected by a dirt degree detecting means such as a gas sensor, and the detected value exceeds a predetermined reference value. Vehicle air conditioners are sometimes known which automatically switch to the inside air circulation mode at times.

[0003]

Since the above-mentioned conventional technique is to switch to the internal air circulation mode when the detection value of the contamination degree detecting means exceeds a predetermined reference value, for example, when the preceding vehicle accelerates. As described above, even when dirty outside air easily enters the passenger compartment, the inside air circulation mode is not switched unless the detected value is equal to or more than the reference value.

However, in reality, when the preceding vehicle accelerates, the occupant visually perceives that dirty outside air enters the vehicle interior, so that the inside air circulation mode is often switched to manually. As described above, there is a problem that the inside / outside air switching mode automatically determined based on the degree of contamination of the outside air and the inside / outside air switching mode selected by the visual sense of the occupant do not necessarily match.

In view of the above problems, the present invention provides an air conditioner for a vehicle in which the inside / outside air switching mode, which is automatically determined based on the degree of contamination of the outside air, can be set to a mode that matches the visual sensation of an occupant. The purpose is to

[0006]

In order to achieve the above object, in the invention according to claim 1, the blower means (2) for generating an air flow and the air generated by the blower means (2) are placed inside the vehicle compartment. An air passage (8) for guiding, an air upstream portion of the air passage (8), an outside air inlet (7) for sucking outside air, and an air upstream portion of the air passage (8). The air taken in from the inside air intake port (6) or the outside air intake port (7), which is formed at the inside air intake port (6) for intake of the inside air and the air downstream side portion of the air passage (8). Outlet (50, 51) for blowing air into the passenger compartment
An inside / outside air opening / closing means (14) for opening / closing the outside air intake opening (7) and the inside air intake opening (6); and an inside / outside air driving means (11) for driving the inside / outside air opening / closing means (14), Dirty degree detecting means (43) for detecting the degree of dirt inside the vehicle interior
And the preceding vehicle acceleration detecting means (45, step 705) for detecting the acceleration of the preceding vehicle, and the stain degree detected by the stain degree detecting means (43) are predetermined reference values (TG
The stain degree determining means (step 707) for determining whether it is larger than 1) and the stain degree determining means (step 707) determine the stain degree to the reference value (T).
If it is determined that the inside air / outside air opening / closing means (14) closes the outside air suction opening (7) and opens the inside air suction opening (6), the inside / outside air driving means (11) is controlled. When the first inside / outside air control means (step 708) and the contamination degree determination means (step 707) determine that the contamination degree is less than or equal to the reference value (TG1), the inside / outside air opening / closing means (14) Second inside / outside air control means (step 709) for controlling the inside / outside air driving means (11) so as to close the inside air inlet (6) and open the outside air inlet (7), and the preceding vehicle acceleration detecting means. (4
5, a reference value setting means (step 706) for setting the reference value (TG1) to a small value when the acceleration of the preceding vehicle detected in step 705) becomes equal to or more than a predetermined value (ΔSPn1). To do.

According to the second aspect of the invention, an air blowing means (2) for generating an air flow, an air passage (8) for guiding the air generated by the air blowing means (2) into the vehicle compartment, and the air passage ( 8) an outside air intake port (7) formed at an air upstream side part for sucking outside air, and an inside air intake port (8) formed at an air upstream side part of the air passage (8) for sucking inside air ( 6) and an air outlet (50, for forming the air sucked from the inside air intake port (6) or the outside air intake port (7) into the passenger compartment, the air outlet (50, 51), an inside / outside air opening / closing means (14) for opening / closing the outside air intake port (7) and the inside air intake port (6),
An inside / outside air driving means (11) for driving the inside / outside air opening / closing means (14), a dirt degree detecting means (43) for detecting a dirt degree outside the vehicle compartment, and the dirt degree detecting means (43).
Based on the stain degree detected by the stain degree change rate calculating means for calculating the change rate of the stain degree, the preceding vehicle acceleration detecting means (45, step 705) for detecting the acceleration of the preceding vehicle, and the stain degree change. Contamination degree determination means (step 712) for determining whether the change rate calculated by the rate calculation means is larger than a predetermined reference value (TG2).
And the inside / outside air opening / closing means (14) closes the outside air intake port (7) when the change rate is judged to be larger than the reference value (TG2) by the dirt degree judging means (step 712). A first inside / outside air control means (step 708) for controlling the inside / outside air driving means (11) so as to open the suction port (6) and the contamination degree determining means (step 712), the change rate is set to the reference value. When it is determined that it is smaller than (TG2), the inside / outside air opening / closing means (14) closes the inside air inlet (6) and opens the outside air inlet (7).
Second inside / outside air control means for controlling the air (step 709)
And the preceding vehicle acceleration detecting means (45, step 70
5) A reference value setting means (step 710) for setting the reference value (TG2) to a small value when the acceleration of the preceding vehicle detected by 5) becomes a predetermined value (ΔSPn1) or more.

Further, as described in claim 3, claim 1
Alternatively, in the vehicle air conditioner according to any one of 2 and 3, the reference value setting means (step 706, step 710)
The preceding vehicle acceleration detecting means (45, step 70
When the acceleration of the preceding vehicle detected by 5) becomes equal to or greater than the predetermined value (ΔSPn1), the reference value (TG1, TG2) may be set smaller as the detected acceleration increases. .

Further, as described in claim 4, claim 1
In the vehicle air conditioner described in any one of (1) to (3), the vehicle speed detection means (45) for detecting the vehicle speed of the vehicle, and the acceleration of the vehicle based on the vehicle speed of the vehicle detected by the vehicle speed detection means (45). Own vehicle acceleration calculating means (step 7)
05) is provided, and the preceding vehicle acceleration detecting means (45, step 705) is configured to estimate the acceleration of the preceding vehicle based on the acceleration calculated by the own vehicle acceleration calculating means (step 705). May be.

In the acceleration detecting means according to the first aspect of the invention, detecting the acceleration of the preceding vehicle means indirectly detecting or directly detecting the acceleration of the preceding vehicle. Further, the reference numerals in parentheses of the above means are
It shows a correspondence relationship with a concrete means of an embodiment described later.

[0011]

According to the first aspect of the present invention, when the degree of dirt outside the vehicle compartment detected by the dirt degree detecting means is larger than a predetermined reference value, the inside / outside air opening / closing means closes the outside air intake port. It is a so-called inside air circulation mode in which the suction port is opened. When the degree of dirt outside the vehicle compartment detected by the dirt degree detecting means is equal to or less than the reference value, the inside / outside air opening / closing means closes the inside air inlet and opens the outside air inlet, which is a so-called outside air introduction mode.

Here, when the acceleration of the preceding vehicle detected by the preceding vehicle acceleration detecting means exceeds a predetermined value, the reference value setting means sets the reference value to a small value to facilitate the internal air circulation mode. That is, when the preceding vehicle is accelerating, that is, when the engine speed of the preceding vehicle is high and the amount of exhaust gas is large, the inside air circulation mode is likely to be set. As a result, when dirty outside air enters the passenger compartment, the occupant can easily switch to the inside air circulation mode, and the inside / outside air switching mode becomes a mode suitable for the occupant's visual sensation.

According to the second aspect of the present invention, when the change rate of the dirt degree calculated by the dirt degree change rate calculating means is larger than a predetermined reference value, the inside air circulation mode is set,
If the rate of change is less than or equal to the reference value, the outside air introduction mode is set. Then, when the acceleration of the preceding vehicle detected by the preceding vehicle acceleration detecting means becomes equal to or larger than the predetermined value, the reference value setting means sets the reference value to a small value to facilitate the internal air circulation mode. As a result, when dirty outside air enters the passenger compartment, the occupant can easily switch to the inside air circulation mode, and the inside / outside air switching mode becomes a mode suitable for the occupant's visual sensation.

Further, as the acceleration of the preceding vehicle increases, the amount of exhaust gas from the preceding vehicle also increases. Therefore, by configuring the invention as claimed in claim 3, the amount of exhaust gas from the preceding vehicle increases. It becomes easy to enter the circulation mode. Further, in the invention according to claim 4, since the acceleration of the preceding vehicle is estimated from the acceleration of the own vehicle calculated from the detection value of the existing own vehicle speed detecting means, the acceleration of the preceding vehicle is detected. It is possible to avoid an increase in cost due to providing the means separately.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a first embodiment of the present invention will be described with reference to the drawings. First, the overall configuration of this embodiment will be described with reference to FIG. The vehicle air conditioner of the present embodiment is equipped with an automatic air conditioner function for automatically maintaining the temperature inside the vehicle compartment at a set temperature. The vehicle air conditioner is roughly classified into an air conditioning unit 1 and this air conditioning unit 1. The ECU 27 is configured to control each functional component.

(Description of Air Conditioning Unit 1) Air Conditioning Unit 1
Is a duct 8 for introducing air into the vehicle interior, and an inside / outside air switching means 4 for switching whether the air taken into the duct 8 is air inside the vehicle interior (inside air) or air outside the vehicle interior (outside air).
A blower 2 for blowing the air selected by the inside / outside air switching means 4 into the passenger compartment, a blower driving means 17 for driving the blower 2, a cooling means 12 for cooling the air flowing through the duct 8, and a duct 8 Temperature adjusting means 13 for adjusting the temperature of the air blown into the vehicle interior from the vehicle.

The inside / outside air switching means 4 is provided at the air suction port of the blower 2, and is connected to the inside of the vehicle compartment for sucking the inside air into the duct 8, and the outside air for communicating with the outside of the vehicle compartment. An outside air suction port 7 for sucking into the duct 8 and an inside / outside air switching door 14 that selectively opens and closes the inside air suction port 6 and the outside air suction port 8 are provided. The inside / outside air switching door 14 is driven by the servo motor 11, and has an inside air circulation mode in which the inside air is sucked in from the inside air inlet 6 and circulates in the vehicle compartment, and the outside air is sucked in from the outside air inlet 7 into the vehicle compartment. The external air introduction mode to be introduced is selectively switched.

The blower 2 is provided in the duct 8 at a location downstream of the inside / outside air switching means 4 on the air side, and generates an air flow toward the passenger compartment. The blower 2 is composed of a fan case 15, a fan 16, and a blower driving means (specifically, a fan motor) 17, and the fan motor 17 responds to a voltage applied from the blower drive circuit 5 to the fan 1
6 is rotationally driven to blow the inside air or the outside air into the vehicle compartment through the duct 8.

The duct 8 is arranged in the front of the passenger compartment, and the face duct 2 is provided at the air downstream side of the duct 8.
9, a foot duct 30, and a defroster duct (not shown) are formed. Face duct 2 of these
The air that has passed through 9 is blown from the face outlet 50 toward the upper body of the passenger in the passenger compartment, and the air that has passed through the foot duct 30 is blown from the foot outlet 51 toward the feet of the passenger in the passenger compartment, and the defroster duct The air that has passed through is blown out toward the inner surface of the windshield from a defroster outlet (not shown).

In the duct 8, a duct switching door serving as an outlet opening / closing means for selectively opening / closing the face duct 29 or the foot duct 30 is provided at a portion where the duct 8 branches into the face duct 29 and the foot duct 30. Three
Two are provided. The duct switching door 32 is driven by driving means 33 such as a servo motor. The cooling means 12 is an evaporator which is a component of a well-known refrigeration cycle (not shown). The cooling means 12 is arranged in the duct 8 and cools the air in the duct 8 by the heat of vaporization of the refrigerant flowing inside itself. To do.

The heating means 9 is specifically a heater core through which engine cooling water flows, and heats the air in the duct 8 by the heat of the engine cooling water. The temperature adjusting means 13 includes a heater core 9, a bypass passage 22 that bypasses the heater core 9, and an air mix door 10 that adjusts the amount of cool air from the evaporator 12 to the heater core 9 and the amount of air to the bypass passage 22. Composed of. The air mix door 10 is driven by a driving means 21 such as a servo motor.

(Description of ECU 27) The ECU 27 is a control device for controlling each electric functional component of the air conditioning unit 1 described above, and is a well-known device having a CPU, a ROM, and a RAM (not shown). A program for air conditioning control is stored in the ROM, and various calculations and processing are performed based on the air conditioning information temporarily stored in the RAM.

The input terminal of the ECU 27 has an inside / outside air changeover switch 3 for manually changing over between the inside / outside air changeover mode.
5. Temperature setting device 36 for manually setting the temperature inside the passenger compartment, blowing mode setting switch 3 for manually setting the blowing mode
7 and a gas operation switch 44 for controlling the inside / outside air switching mode based on the value of a gas sensor 43 described later. Further, the inside / outside air switching switch 35, the temperature setting device 36, the blowout mode setting switch 37, and the gas operation switch 44 are provided on the operation panel 34 provided at a position (for example, an instrument panel) where operability is good in the vehicle interior. ing.

At the input terminal of the ECU 27, an inside air temperature sensor 38 for detecting the inside air temperature, an outside air temperature sensor 39 for detecting the outside air temperature, a solar radiation sensor 40 for detecting the amount of solar radiation applied to the vehicle interior, and an evaporator 12 are provided. A post-evaporator sensor 41 that detects the air temperature immediately after passing, a water temperature sensor 42 that detects the engine cooling water temperature in the heater core 9, a gas sensor 43 that detects the degree of contamination outside the vehicle compartment, and a vehicle speed sensor 45 that detects the vehicle speed of the vehicle. Also, an applied voltage detection circuit 60 for detecting the voltage actually applied to the fan motor 17 via the blower drive circuit 5 is connected thereto.

The gas sensor 43 is made of N-type semiconductor SnO2. This gas sensor 43 is
It has a high resistance value when it comes into contact with oxygen in the air, and has a property that it has a low resistance value due to an oxidation reaction when it comes into contact with reducing gases such as methane gas and carbon monoxide in the air. In the example, the degree of dirt outside the vehicle compartment is detected based on the current value based on the resistance value.

Further, the output terminals of the ECU 27 are connected to the servomotors 11, 21, 33 and the blower drive circuit 5,
Control signals are output to these actuators. Next, the operation of this embodiment will be described based on the flowchart of FIG. First, in step 100, the inside air temperature sensor 3
8, the inside air temperature signal Tr from the outside air temperature sensor 39, the outside air temperature signal Tam from the outside air temperature sensor 39, and the solar radiation amount signal T from the solar radiation sensor 40.
s, the post-evaporator temperature signal Te from the post-evaporator sensor 41,
The water temperature signal Tw from the water temperature sensor 42, the gas signal TG from the gas sensor 43, and the vehicle speed signal SPn from the vehicle speed sensor 45 are read.

Next, at step 200, the operation panel 34
Signal from the inside / outside air selector switch 35, the set temperature signal Tset from the temperature setting device 36, the signal from the blowout mode setting switch 37, and the gas operation switch 44.
Read each signal from. Next, in step 300, the required blown air temperature into the vehicle interior (hereinafter referred to as TAO) is calculated based on the following mathematical expression 1.

[0028]

## EQU1 ## TAO = Kset × Tset−Kr × Tr−Kam ×
Tam-Ks * Ts-C Here, Kset, Kr, Kam, and Ks are gains respectively, and C is a correction constant.

Next, at step 400, the target opening SW of the air mix door 10 is calculated and output based on the following equation 2 using the above TAO.

[0030]

## EQU2 ## SW = {(TAO-Te) / (Tw-Te)}
× 100 (%) Next, in step 500, based on the characteristics shown in FIG.
A face that blows out conditioned air from the face outlet 50 (F
ACE mode, bi-level (B / B) that blows out conditioned air from both the face outlet 50 and the foot outlet 51.
The blowout mode is determined and output between the L) mode and the foot (FOOT) mode in which the conditioned air is blown from the foot blowout port 51. The characteristics shown in FIG. 4 are stored in the ROM.

Next, at step 600, the blower drive circuit 5 determines and outputs the blower voltage to be applied to the fan motor 17 based on the characteristics shown in FIG. The characteristics shown in FIG. 5 are stored in the ROM. Then step 70
At 0, the inside / outside air switching mode is determined and output. Here, the control content of step 700, which is the main part of this embodiment, will be described in detail with reference to FIG.

First, at step 701, the operating state of the inside / outside air selector switch 35 is determined. That is, it is determined whether or not the inside / outside air switching mode is automatically controlled.
If it is determined that the inside / outside air changeover switch 35 is turned on (the inside / outside air changeover mode is manually controlled), the routine proceeds to step 702, where the servo is set to the mode instructed by the inside / outside air changeover switch 35. A control signal is output to the motor 11.

At step 701, the inside / outside air selector switch 3
When it is determined that 5 is off (the inside / outside air switching mode is automatically controlled), the routine proceeds to step 703, where it is determined whether the gas operation switch 44 is on. That is, it is determined whether the inside / outside air switching mode is controlled based on the detection value of the gas sensor 43. If it is determined that the gas operation switch 44 is off (NO), the routine proceeds to step 704, where the inside / outside air switching mode is determined based on the characteristics of FIG. 6 and output.

If YES is determined in the step 703, the acceleration ΔSPn of the own vehicle is calculated based on the following equation 3 in a step 705.

[0035]

## EQU00003 ## .DELTA.SPn = (SPn-SPn-1) / t where SPn is the current vehicle speed read in step 100, and SPn-1 is step 10 one cycle before.
It is the vehicle speed of the vehicle read at zero. Further, t is a vehicle speed detection cycle.

Then, in the next step 706, the reference value TG1 to be described later is set based on the characteristics of FIG. 7 using the ΔSPn calculated in step 705. The characteristics shown in FIG. 7 are stored in the ROM. And step 70
In step 7, the detection value TG of the gas sensor 43 is the same as in step 7 above.
It is determined whether or not it is larger than the reference value TG1 set in 06, and if it is larger than TG1, the inside air circulation mode is set, and if it is TG1 or less, the outside air introduction mode is set.
At 8,709, the inside / outside air switching mode is determined and output.

By performing the above series of controls, the degree of contamination of the outside air (detection value TG of the gas sensor 43) and the time change of the inside / outside air switching mode are as shown in FIG. Here, when the acceleration ΔSPn of the host vehicle is equal to or greater than a predetermined value (ΔSPn1), the reference value TG1 increases as ΔSPn increases.
The reason why the value is set small will be described below.

First, the fact that the own vehicle has accelerated is regarded as the preceding vehicle accelerating or has already accelerated. When the preceding vehicle accelerates, the engine speed of the preceding vehicle increases, and the exhaust gas amount from the preceding vehicle increases accordingly. In such a case, the passenger visually feels that the exhaust gas enters the passenger compartment. Therefore, in the present embodiment, when the preceding vehicle can be regarded as being in an accelerating state, that is, when the acceleration of the host vehicle is equal to or greater than a predetermined value, the reference value TG1 is set small to facilitate the internal air circulation mode. . By doing so, when the occupant visually feels when the exhaust gas enters the vehicle interior, it becomes easier to enter the internal air circulation mode,
The inside / outside air switching mode is a mode that matches the sensation of the occupant.

Further, in this embodiment, the acceleration ΔSP of the vehicle is
When n is ΔSPn1 or more and ΔSPn2 or less, the reference value TG1 is set to linearly decrease as ΔSPn increases, so the reference value TG1 is set to a value according to the exhaust gas amount from the preceding vehicle. It Furthermore, in this embodiment,
Since the acceleration of the preceding vehicle is estimated by using the existing sensor, that is, the vehicle speed sensor 45 of the own vehicle, it is possible to suppress the cost increase by separately providing the sensor only for detecting the acceleration of the preceding vehicle.

Next, a second embodiment of the present invention will be described. Since the overall configuration of this embodiment is the same as that of the first embodiment, its description is omitted. The control flow of this embodiment is as shown in FIG. 3 and is basically the same as that of the first embodiment. Of these, only the contents of step 700 are different, so only this part will be explained using FIG. . Note that the control contents of the portions in FIG. 9 designated by the same reference numerals as those in FIG. 1 are the same as those in FIG.

As shown in FIG. 9, after the acceleration ΔSPn of the vehicle is calculated in step 705, in step 710, the ΔSPn calculated in step 705 is used to calculate the acceleration ΔSPn of FIG.
A reference value TG2 described later is set based on the characteristic of 0.
The characteristics shown in FIG. 10 are stored in the ROM. Then, in step 711, the change rate Δ of the degree of contamination of the outside air
TG is calculated based on the following mathematical formula 4.

[0042]

## EQU4 ## ΔTG = TGn-TGn-1 where TGn is the current detection value of the gas sensor 43 read in step 100, and TGn-1 is the gas sensor 43 read in step 100 one cycle before. It is a detected value.

Then, in the next step 712, it is determined whether or not the change rate ΔTG calculated in step 711 is larger than the reference value TG2 set in step 710. Then, the inside / outside air switching mode is determined so as to be the inside air circulation mode if it is larger than the reference value TG2, and the outside air introduction mode if it is not more than the reference value TG2, and output.

In each of the embodiments described above, the method of estimating the acceleration of the preceding vehicle from the acceleration of the own vehicle is adopted as the method of detecting the acceleration of the preceding vehicle. A means for detecting the inter-vehicle distance may be provided, and the acceleration of the preceding vehicle may be detected from this value and the speed of the own vehicle. In this case, the acceleration of the preceding vehicle can be detected more accurately than in each of the above embodiments.

Each step in the flow chart of each of the above embodiments constitutes means for realizing each function.

[Brief description of drawings]

FIG. 1 is a flowchart showing a main part of a first embodiment of the present invention.

FIG. 2 is an overall configuration diagram of the above embodiment.

FIG. 3 is a flowchart of the above embodiment.

FIG. 4 is a characteristic diagram showing a relationship between a target outlet air temperature (TAO) and an outlet mode.

FIG. 5 is a characteristic diagram showing a relationship between the TAO and a blower voltage.

FIG. 6 is a characteristic diagram showing a relationship between the TAO and an inside / outside air switching mode.

FIG. 7 is a characteristic diagram showing a relationship between an acceleration ΔSPn of the own vehicle and a reference value TG1.

FIG. 8 is a diagram showing a temporal change in a gas sensor detection value and an inside / outside air switching mode.

FIG. 9 is a flowchart showing a main part of the second embodiment of the present invention.

FIG. 10 is a characteristic diagram showing the relationship between the acceleration ΔSPn of the own vehicle and the reference value TG2 in the second embodiment.

[Explanation of symbols]

2 Blower (Blower) 6 Inside air intake 7 Outside air intake 8 Duct (Air passage) 11 Servo motor (Inside / Outside air drive unit) 14 Inside / Outside air switching door (Inside / Outside air opening / closing unit) 43 Gas sensor (Dirt degree detecting unit) 45 Vehicle speed Sensor (preceding vehicle acceleration detecting means, own vehicle speed detecting means) 50 face outlet 51 foot outlet

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 58-47617 (JP, A) JP 5-286348 (JP, A) JP 57-186513 (JP, A) JP 5- 254339 (JP, A) JP-A-57-167818 (JP, A) JP-A-7-69040 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60H 1/00-3 / 06

Claims (4)

(57) [Claims] 1. An air blower for generating an air flow, an air passage for guiding the air generated by the blower into a passenger compartment, and an outside air suction member formed at an air upstream side portion of the air passage for sucking outside air. A mouth, an inside air inlet formed in an air upstream side portion of the air passage for sucking inside air, and an air downstream side portion of the air passage formed in the air passage, and sucked from the inside air inlet or the outside air inlet An air outlet for blowing air into the passenger compartment, an inside / outside air opening / closing means for opening / closing the outside air intake opening and the inside air intake opening, an inside / outside air driving means for driving the inside / outside air opening / closing means, and a degree of contamination outside the vehicle compartment A dirt level detecting unit for detecting the acceleration of the preceding vehicle, a preceding vehicle acceleration detecting unit for detecting the acceleration of the preceding vehicle, and a dirt level for determining whether or not the dirt level detected by the dirt level detecting unit is larger than a predetermined reference value. And the inside / outside air opening / closing means closes the outside air intake port and opens the inside air intake port when the contamination level is determined to be greater than the reference value When the contamination degree is determined to be equal to or less than the reference value by the first inside / outside air control means for controlling the means and the contamination degree determination means, the inside / outside air opening / closing means closes the inside air inlet and the outside air inlet. A second inside / outside air control means for controlling the inside / outside air driving means so as to open, and when the acceleration of the preceding vehicle detected by the preceding vehicle acceleration detecting means becomes a predetermined value or more, the reference value is set small. And a reference value setting means for controlling the vehicle air conditioner. 2. An air blower for generating an air flow, an air passage for guiding the air generated by the blower into the passenger compartment, and an outside air suction member formed at an air upstream side portion of the air passage for sucking outside air. A mouth, an inside air inlet formed in an air upstream side portion of the air passage for sucking inside air, and an air downstream side portion of the air passage formed in the air passage, and sucked from the inside air inlet or the outside air inlet An air outlet for blowing air into the passenger compartment, an inside / outside air opening / closing means for opening / closing the outside air intake opening and the inside air intake opening, an inside / outside air driving means for driving the inside / outside air opening / closing means, and a degree of contamination outside the vehicle compartment And a dirt degree change rate calculating means for calculating a change rate of the dirt degree based on the dirt degree detected by the dirt degree detecting means, and a destination for detecting the acceleration of the preceding vehicle. The vehicle acceleration detecting means, the dirt degree determining means for judging whether or not the change rate calculated by the dirt degree changing rate calculating means is larger than a predetermined reference value, and the change rate by the dirt degree judging means. If it is determined that the inside / outside air opening / closing means closes the outside air intake opening and opens the inside air intake opening, the inside / outside air driving means controls the inside / outside air driving means, and the degree of contamination is determined. If the change rate is determined to be smaller than the reference value by the determination means, the inside / outside air opening / closing means controls the inside / outside air driving means to close the inside air inlet and open the outside air inlet. Air control means and reference value setting means for setting the reference value small when the acceleration of the preceding vehicle detected by the preceding vehicle acceleration detecting means becomes a predetermined value or more. A vehicle air conditioner characterized by the above. 3. When the acceleration of the preceding vehicle detected by the preceding vehicle acceleration detecting means becomes equal to or more than the predetermined value, the reference value setting means sets the reference value to be smaller as the detected acceleration increases. The vehicle air conditioner according to claim 1, wherein the air conditioner is configured to operate. 4. An own vehicle speed detecting means for detecting a vehicle speed of the own vehicle, and an own vehicle acceleration calculating means for calculating an acceleration of the own vehicle based on the vehicle speed of the own vehicle detected by the own vehicle speed detecting means, 4. The vehicle according to claim 1, wherein the preceding vehicle acceleration detecting means is configured to estimate the acceleration of the preceding vehicle based on the acceleration calculated by the own vehicle acceleration calculating means. Air conditioner.