Vehicle air conditioning apparatus

• US 20050121185A1
• Filed: 12/03/2004
• Published: 06/09/2005
• Est. Priority Date: 12/04/2003
• Status: Active Grant

• Current Assignee: Keihin Corporation (Hitachi, Ltd.)
• Original Assignee: Keihin Corporation (Hitachi, Ltd.)
• Inventors: Washiashi, Junya, Yonekura, Mitsuru
• Granted Patent: US 7,269,963 B2
• Time in Patent Office: Days
• US Class Current: 165/202
• CPC Class Codes: B60H 1/00785 by the detection of humidity or frost
• CPC Class Codes: B60H 1/00864 Ventilators and damper doors
• CPC Class Codes: B60H 1/00878 the components being temperature regulating devices
• CPC Class Codes: B60H 1/3207 for minimizing the humidity of the air
• CPC Class Codes: B60H 2001/3245 of air
• CPC Class Codes: B60H 2001/3261 of the air at an evaporating unit
• CPC Class Codes: B60H 2001/3266 related to the operation of the vehicle
• CPC Class Codes: B60H 2001/327 related to a compressing unit

Abstract

Parameters are set in accordance with a running condition of a vehicle and an environmental condition based on a wiper operation signal of the vehicle. The parameters are used to calculate a stable vehicle interior surface temperature Tna of a window glass. The stable vehicle interior surface temperature Tna and a vehicle interior surface temperature Tn1 calculated at previous sampling are used to calculate a vehicle interior surface temperature Tn in a transient state considering response delay time τ of temperature change. A control temperature, at which no dew is formed on the window glass, is determined in accordance with the obtained vehicle interior surface temperature Tn to perform air conditioning control.

Claims

1. A vehicle air conditioning apparatus for performing air conditioning control in a vehicle passenger compartment by controlling a heater and a cooler, said apparatus comprising:

an outside air temperature sensor which detects an outside air temperature Tam of a vehicle at time tA;

a vehicle interior temperature sensor which detects a vehicle interior temperature Tr of said vehicle at said time tA;

a solar radiation amount sensor which detects a solar radiation amount Ts on said vehicle at said time tA;

a stable vehicle interior surface temperature-calculator which calculates a vehicle interior surface temperature Tna of a window glass in a stable state at said time tA by an expression;

Tna=k1·

Tr+k2·

Tam+k3·

Ts

wherein parameters k1 to k3 are determined by physical characteristics of said window glass and said vehicle passenger compartment;

a transient vehicle interior surface temperature-calculator which calculates a vehicle interior surface temperature Tn of said window glass in a transient state at said time tA by expressions;

Tn′

=Tna−

(Tna−

Tn1)exp(−

φ

t)
Tn≈

Tnτ

′

wherein Tn1 is an initial value of said vehicle interior surface temperature Tn, t is elapsed time from a state of said initial value Tn1 to said time tA, τ

is response delay time of temperature change of a vehicle interior surface of said window glass, and a parameter φ

is determined by said physical characteristics of said window glass and said vehicle passenger compartment provided that Tnτ

′

is a vehicle interior surface temperature Tn′

calculated at time before said time tA by said response delay time τ

;

wherein said air conditioning control is performed by using said vehicle interior surface temperature Tn.

2. The vehicle air conditioning apparatus according to claim 1, further comprising:

a vehicle speed sensor which detects a speed V of said vehicle at said time tA,

said parameters k1 to k3 and φ

being set as functions of said vehicle speed V.

3. The vehicle air conditioning apparatus according to claim 1, further comprising:

an environmental condition-setting unit which sets an environmental condition for said vehicle,

said parameters k1 to k3 and φ

being set corresponding to said environmental condition.

4. The vehicle air conditioning apparatus according to claim 3, wherein said environmental condition-setting unit is a wiper-driving unit which outputs a wiper operation signal to indicates that a wiper of said vehicle is operated.

5. The vehicle air conditioning apparatus according to claim 1, wherein said stable vehicle interior surface temperature-calculator calculates said vehicle interior surface temperature Tna at said time tA by an expression:

$\mathrm{Tna}=\left[\left(\mathrm{Kn}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\lambda <br><br>}+2<br><br>\mathrm{KnLKg}\right)/\left(\mathrm{Kn}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\lambda <br><br>}+\mathrm{Kg}<br><br>\left(\mathrm{\lambda <br><br>}+2<br><br>\mathrm{KnL}\right)\right)\right]<br><br>\mathrm{Tr}+<br><br>\text{\hspace{1em}<br><br>}<br><br>\left[\mathrm{\lambda <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>K<br><br>\text{\hspace{1em}<br><br>}<br><br>g/\mathrm{Kn}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\lambda <br><br>}+\mathrm{Kg}<br><br>\left(\mathrm{\lambda <br><br>}+2<br><br>\mathrm{KnL}\right)\right)]<br><br>\mathrm{\xi <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{Tam}+1/A<br><br>\left[\left(\mathrm{\lambda <br><br>}+\mathrm{LKg}\right)/\left(\mathrm{Kn}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\lambda <br><br>}+\mathrm{Kg}<br><br>\left(\mathrm{\lambda <br><br>}+2<br><br>\mathrm{KnL}\right)\right)\right]<br><br>\mathrm{\varepsilon <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{Ts}<br><br>\text{\hspace{1em}<br><br>}$

L;

a window glass thickness;

Kg;

an outside air coefficient of thermal conductivity;

Kn;

a vehicle interior coefficient of thermal conductivity;

λ

;

a coefficient of thermal conductivity of a glass;

A;

a glass surface area;

ξ

;

a water droplet temperature changing rate;

ε

;

a solar radiation amount conversion coefficient.

6. The vehicle air conditioning apparatus according to claim 5, further comprising:

a vehicle speed sensor which detects a speed V of said vehicle at said time tA; and

an environmental condition-setting unit which sets an environmental condition for said vehicle, wherein

said stable vehicle interior surface temperature-calculator sets a coefficient of thermal conductivity changing rate ψ and

said water droplet temperature changing rate ξ

to predetermined values in accordance with said environmental condition, and said stable vehicle interior surface temperature-calculator sets said outside air coefficient of thermal conductivity Kg to ψ

(xV+y) at said time tA by using parameters x and y in accordance with said coefficient of thermal conductivity changing rate ψ and

said vehicle speed V.

7. The vehicle air conditioning apparatus according to claim 1, further comprising:

a vehicle speed sensor which detects a speed V of said vehicle at said time tA; and

an environmental condition-setting unit which sets an environmental condition for said vehicle, wherein

said transient vehicle interior surface temperature-calculator makes the following approximation by an expression;

exp(−

φ

t)≈

(wV+z)

provided that said elapsed time t is a sampling time interval for said vehicle air conditioning apparatus;

wherein a change ratio ω

is set to a predetermined value in accordance with said environmental condition, and said vehicle interior surface temperature Tn is calculated by using parameters w and z.

8. The vehicle air conditioning apparatus according to claim 1, wherein said transient vehicle interior surface temperature-calculator regards said vehicle interior surface temperature Tna at calculation start time t1 as said vehicle interior surface temperature Tn, when said elapsed time t, which is started from said calculation start time t1 for said vehicle interior surface temperature Tn, does not elapse said response delay time τ

.