Air-conditioning method and system for an automotive vehicle

• US 4,450,897 A
• Filed: 11/03/1981
• Issued: 05/29/1984
• Est. Priority Date: 11/04/1980
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Takahashi, Seiichi, Iijima, Tetsuya
• Primary Examiner(s): Cline, William R.
• Assistant Examiner(s): Ford, John K.
• Application Number:
  US06/317,861
• Time in Patent Office: 938 Days
• Field of Search: 165/12, 165/2, 165/14, 165/16, 165/25, 165/43, 165/42, 165/28, 165/30, 236/49, 236/91 D, 236/91 E, 236/91 G, 236/13, 237/5, 237/12.3 B
• US Class Current: 165/202
• CPC Class Codes: B60H 1/00835 Damper doors, e.g. position control construction or arrangement of damper doors B60H1/00664; B60H1/00864 takes precedence
• CPC Class Codes: G05D 23/1917 using digital means
• CPC Class Codes: G05D 23/20 with sensing elements having variation of electric or magnetic properties with change of temperature G05D23/13 takes precedence

Abstract

An air-conditioning method and system controls the temperature of air outputted from an air conditioner outlet duct into the passenger compartment of a vehicle at a constant level, with a small time constant of recovery, by adjusting the air mix door opening percentage. The air-conditioning method comprises the steps of calculating a target outlet duct air temperature on the basis of a preset passenger compartment air temperature, a detected outside-air temperature, and a detected passenger compartment air temperature in accordance with a heat equilibrium equation and calculating an air mix door opening percentage on the basis of the calculated target outlet duct air temperature in accordance with a linear interpolation between two endpoints of a selected one of three characteristics representative of relationships between outlet duct air temperature and air mix door opening percentage respectively stored for outside-air introduction mode, inside-air recirculation mode, and cooler compressor operation mode.

Claims

1. An air conditioning method for an automotive vehicle air conditioning system in which the temperature of air outputted into a passenger compartment is controlled by the opening percentage of an air mix door, which comprises the following steps of:

(a) detecting air temperature at a plurality of locations, including at least outside air temperature T_A and passenger compartment air temperature T_p ;

(b) determining a desired passenger compartment air temperature T_O preset by a passenger compartment air temperature preset device;

(c) calculating a required target outlet duct air temperature T_AC as a function of outside air temperature T_A, passenger compartment air temperature T_p and desired passenger compartment air temperature T_O using a predetermined equation;

(d) determining an air introduction condition selected by the passenger;

(e) calculating an air mix door opening percentage required to produce outlet duct air at temperature T_AC from one of a plurality of stored characteristic curves involving a predetermined relationship;

of outlet duct air temperature T_AC, passenger compartment air temperature T_p and air introduction condition, to air mix door opening percentage X;

said characteristic curves being stored as a pair of endpoint values T_L and T_H representing extreme values of outlet duct air temperature T_AC for the corresponding passenger compartment T_p and air introduction condition, the calculating step being performed by linearly interpolating the target outlet duct air temperature T_AC with respect to the endpoint values T_L and T_H ; and

(f) positioning the air mix door in accordance with the calculated value of X.

2. An air conditioning method for an automotive vehicle air conditioning system in which the temperature of air outputted into a passenger compartment is controlled by the opening percentage of an air mix door as set forth in claim 1, wherein the predetermined equation to calculate the required target outlet duct air temperature T_AC is

3. An air conditioning method for an automotive vehicle air conditioning system in which the temperature of air outputted into a passenger compartment is controlled by the opening percentage of an air mix door as set forth in claim 1, wherein the step of calculating an air mix door opening percentage X comprises the following steps of:

(a) storing said plurality of characteristic curves indicative of relationships between outlet duct air temperature T_AC, and air mix door opening percentage X with passenger compartment air temperature T_p as a parameter, the characteristic curves being stored corresponding to each air introduction condition;

(b) selecting one of the stored characteristic curves corresponding to the determined air introduction condition, in response to the detected passenger compartment air temperature T_p ;

(c) retrieving the values of a first endpoint outlet duct air temperature T_L obtained when the air mix door is fully closed and a second endpoint outlet duct air temperature T_H obtained when the air mix door is fully open from the selected characteristic curve; and

(d) calculating the air mix door opening percentage X from the values of the current calculated outlet duct air temperature T_AC, and in accordance with the linear interpolation between the retrieved first and second endpoint outlet duct air temperatures T_L and T_H according to the following equation;

space="preserve" listing-type="equation">X=(1-[T.sub.AC -T.sub.H ]/[T.sub.L -T.sub.H ])×

100%.

4. An air conditioning method for an automotive vehicle air conditioning system in which the temperature of air outputted into a passenger compartment is controlled by the opening percentage of an air mix door as set forth in claim 1, wherein the air introduction condition can be any of the three following conditions:

(1) cooler compressor operation mode in which a compressor within the air conditioning system operates to cool air introduced thereinto, the step of calculating the air mix door opening percentage X according to the characteristic curve corresponding to this mode being not dependent upon the value of passenger compartment air temperature T_p ;

(2) outside air-introduction mode in which the compressor is not operating and air is introduced into the air conditioning system only from outside the vehicle, the step of calculating the air mix door opening percentage X according to the characteristic curves corresponding to this mode being dependent upon the value of passenger compartment air temperature T_p ; and

(3) inside-air recirculation mode in which the compressor is not operating and air is introduced into the air conditioner only from inside the passenger compartment, the step of calculating the air mix door opening percentage X according to the characteristic curve corresponding to this mode being dependent upon the value of passenger compartment air temperature T_p.

5. An air-conditioning system for an automotive vehicle in which the temperature of air outputted from an air conditioner outlet duct into a passenger compartment is controlled by adjusting an air mix door, which comprises:

(a) a passenger compartment air temperature presetting device;

(b) an outside-air temperature sensor;

(c) a passenger compartment air temperature sensor;

(d) an air mix door opening percentage sensor for detecting the opening percentage of the air mix door;

(e) a cooler compressor actuating switch for detecting whether a cooler compressor is in operation or not;

(f) an air intake door switch for detecting whether air outputted from the air outlet duct into the passenger compartment is introduced from the outside or recirculated within the passenger compartment;

(g) a target outlet duct air temperature calculating means for calculating a target outlet duct air temperature T_AC on the basis of the passenger compartment temperature T_O preset by said passenger compartment air temperature presetting device, the outside-air temperature T_A detected by said outside-air temperature sensor, and the passenger compartment air temperature T_P detected by said passenger compartment air temperature sensor;

(h) an air mix door opening percentage calculating means for calculating an air mix door opening percentage X by substituting into a proportion expression the calculated target outlet duct air temperature T_AC obtained by said target outlet duct air temperature calculating means, an outlet duct air temperature T_H when the air mix door is fully open at a detected passenger compartment air temperature T_P, and an outlet duct air temperature T_L when the air mix door is fully closed at the detected air temperature T_P, the outlet duct air temperatures T_H and T_L being obtained, respectively, in accordance with first characteristic curves representative of first relationships between outlet duct air temperature T_AC and air mix door opening percentage X varying with respect to the detected passenger compartment air temperature T_P detected by said passenger compartment air temperature sensor in the case when said cooler compressor actuating switch detects that the cooler compressor is not in operation and said air intake door switch detects that air outputted from the air outlet duct into the passenger compartment is introduced from the outside, second characteristic curves representative of second relationships between outlet duct air temperature T_AC and air mix door opening percentage X varying with respect to the detected passenger compartment air temperature T_P detected by said passenger compartment air temperature sensor in the case when said cooler compressor actuating switch detects that the cooler compressor is not in operation and said air intake door switch detects that air outputted from the air outlet duct into the passenger compartment is recirculated from within the passenger compartment, and a third characteristic curve representative of a third relationship between outlet duct air temperature T_AC and air mix door opening percentage X independent of the detected passenger compartment air temperature T_p in the case when cooler compressor actuating switch detects that the cooler compressor is in operation;

(i) a comparator for comparing the calculated air mix door opening percentage X obtained by said air mix door opening percentage calculating means with an air mix door opening percentage X'"'"' detected by said air mix door opening percentage sensor;

(j) an air mix door actuator driver responsive to said comparator for outputting an air mix door actuating signal when the calculated air mix door opening percentage X is not equal to the detected air mix door opening percentage X'"'"'; and

(k) an air mix door actuator for positioning the air mix door in response to the signal outputted from said air mix door actuator driver,

whereby the outlet duct air temperature is controlled at a constant level with a small time constant of recovery in an outside-air introduction mode, an inside-air recirculation mode, and a cooler compressor operation mode, respectively.

7. An air-conditioning system for an automotive vehicle in which the temperature of air outputted from an air conditioner outlet duct into a passenger compartment is controlled by adjusting an air mix door as set forth in claim 5, wherein said passenger compartment air temperature presetting device, said outside air temperature sensor, said passenger compartment air temperature sensor and said air mix door opening percentage sensor generate analog signals and said system further comprises:

(a) an A-D converter for converting the analog signals from said passenger compartment air temperature presetting device, said outside-air temperature sensor, said passenger compartment air temperature sensor, and said air mix door opening percentage sensor, respectively, into corresponding digital signals; and

(b) a D-A converter for converting a digital signal outputted from said comparator into an analog signal, the converted analog signal being inputted to said actuator driver.

8. An air conditioning system for an automotive vehicle in which the temperature of air outputted from an air conditioner outlet duct into a passenger compartment is controlled by adjusting an air mix door as set forth in either claim 5 or 6, wherein said actuator driver comprises:

(a) a first solenoid valve for introducing vacuum pressure from an engine intake manifold into said actuator in order to adjust the air mix door opening percentage; and

(b) a second solenoid valve for releasing the pressure of said actuator in order to adjust the air mix door opening percentage.

6. An air-conditioning system for an automotive vehicle in which the temperature of air outputted from an air conditioner outlet duct into a passenger compartment is controlled by adjusting an air mix door, which comprises:

(a) a passenger compartment air temperature presetting device;

(b) an outside-air temperature sensor;

(c) a passenger compartment air temperature sensor;

(d) an air mix door opening percentage sensor for detecting the opening percentage of the air mix door;

(e) a cooler compressor actuating switch for detecting whether a cooler compressor is in operation or not;

(f) an air intake door switch for detecting whether air outputted from the air outlet duct into the passenger compartment is introduced from the outside or recirculated from within the passenger compartment;

(g) a microcomputer which includes;

(1) a central processing unit for executing various arithmetic operations in accordance with programs;

(2) a read-only memory for storing said programs thereinto;

(3) a random-access memory for storing calculated results produced by said central processing unit in accordance with the program stored in said read-only memory during execution of arithmetic operations;

(4) a clock signal generator for providing a high-frequency clock timing pulse signal,

said central processing unit first calculating a target outlet duct air temperature T_AC on the basis of the passenger compartment temperature T_O preset by said passenger compartment air temperature presetting device, the outside-air temperature T_A detected by said outside-air temperature sensor, and the passenger compartment air temperature T_P detected by said passenger compartment air temperature sensor, in accordance with a predetermined heat equilibrium equation also stored in said read-only memory provided with said microcomputer;

and next calculating an air mix door opening percentage X by substituting into a proportion expression stored in said read-only memory the calculated target outlet duct air temperature T_AC obtained by said central processing unit, an outlet duct air temperature T_H when the air mix door is fully open at a detected passenger compartment air temperature T_P, and an outlet duct air temperature T_L when the air mix door is fully closed at the detected air temperature T_P, the outlet duct air temperature T_H and T_L being obtained, respectively, in accordance with first characteristic curves representative of first relationships between outlet duct air temperature T_AC and air mix door opening percentage X, varying with respect to the detected passenger compartment air temperature T_P detected by said passenger compartment air temperature sensor, in the case when said cooler compressor actuating switch detects that the cooler compressor is not in operation and said air intake door switch detects that air outputted from the air outlet duct into the passenger compartment is introduced from the outside, second characteristic curves representative of second relationships between outlet duct air temperature T_AC and air mix door opening percentage X, varying with respect to the detected passenger compartment air temperature T_P detected by said passenger compartment air temperature sensor, in the case when said cooler compressor actuating switch detects that the cooler compressor is not in operation and said air intake door switch detects that air outputted from the air outlet duct into the passenger compartment is recirculated from within the passenger compartment, and a third characteristic curve representative of a third relationship between outlet duct air temperature T_AC and air mix door opening percentage independent of the detected passenger compartment air temperature T_p in the case when cooler compressor actuating switch detects that the cooler compressor is in operation, the above first, second, and third characteristics being stored in said read-only memory provided within said microcomputer;

(h) said control processing unit comparing the calculated air mix door opening percentage X obtained by said said central processing unit with the air mix door opening percentage X'"'"' detected by said air mix door opening percentage sensor;

(i) an air mix door actuator driver responsive to said microcomputer for outputting an air mix door actuating signal when the calculated air mix door opening percentage X is not equal to the detected air mix door opening percentage X'"'"'; and

(j) an air mix door actuator for positioning the air mix door in response to the signal outputted from said air mix door actuator driver,

whereby the outlet duct air temperature is controlled at a constant level with a small time constant of recovery in an outside-air introduction mode, an inside-air recirculation mode, and a cooler compressor operation mode, respectively.

9. An air-conditioning system for an automotive vehicle comprising:

(1) a cooling unit

(2) a heating unit

(3) air conduit means for feeding air from an intake duct to an outlet duct and into a passenger compartment of the vehicle,

(4) an air mix door

(5) said cooling unit operative to cool air passing from said intake duct to said outlet duct,

(6) said heating unit operative for heating air passing from said intake duct to said outlet duct in proportion to the amount of opening of said air mix door,

(7) an air intake door operative in a fresh air position for opening said intake duct to air outside said passenger compartment and operative in a recirculating air position for opening said air intake duct to air inside said passenger compartment,

(8) a passenger compartment air temperature presetting device operative for generating a first signal;

(9) an outside-air temperature sensor operative for generating a second signal;

(10) a passenger compartment air temperature sensor operative for generating a third signal;

(11) an air mix door opening sensor for detecting the amount of opening of the air mix door and for generating a fourth signal corresponding thereto;

(12) a cooling unit actuating switch for detecting whether said cooling unit is in operation and for generating a fifth signal corresponding thereto;

(13) an air intake door switch for detecting the position of said air intake door and generating a sixth signal corresponding thereto;

(14) a microcomputer connected to receive digital signals corresponding to said first-sixth signals and including;

(a) a central processing unit for executing programs;

(b) a read-only memory for storing said programs; and

(c) a random-access memory for storing results produced by said central processing unit in accordance with the programs stored in said read-only memory;

said central processing unit operative in response to said stored programs and said first-third digital signals for calculating a target outlet duct air temperature T_AC on the basis of a predetermined function involving a passenger compartment temperature T_O corresponding to said first signal and preset by said passenger compartment air temperature presetting device, the outside-air temperature T_A corresponding to said second signal and the passenger compartment air temperature T_p corresponding to said third signal, and for further calculating an air mix door opening amount X required to produce outlet duct air at temperature T_AC from one of a plurality of stored characteristic curves involving a predetermined relationship of outlet duct air temperature T_AC, passenger compartment air temperature T_p and air introduction condition, determined in response to said fifth signal and said sixth signal, to air mix door opening amount X, said characteristic curves being stored in said read only memory as a pair of endpoint values T_L and T_H representing extreme values of outlet duct air temperature T_AC under the corresponding passenger compartment temperature T_p and air introduction condition, the calculating step being performed by linearly interpolating the target outlet duct air temperature T_AC with respect to the endpoint values T_L and T_H ;

(15) said central processing unit operative for comparing the calculated air mix door opening amount X with the air mix door opening amount X'"'"' corresponding to said fourth signal, and generating a control signal if the amount X is different from X'"'"';

(16) an air mix door actuator driver responsive to said control signal for outputting an air mix door actuating signal; and

(17) an air mix door actuator for positioning the air mix door in response to the actuating signal outputted from said air mix door actuator driver,

whereby the outlet duct air temperature is controlled by controlling said air mix door at a constant level with a small time constant of recovery in an outside-air introduction mode, an inside-air introduction mode, and a cooler compressor operation mode, respectively.

10. An air-conditioning system for an automotive vehicle comprising:

(1) a cooling unit

(2) a heating unit

(3) air conduit means for feeding air from an intake duct to an outlet duct and into a passenger compartment of the vehicle,

(4) an air mix door

(5) said cooling unit operative to cool air passing from said intake duct to said outlet duct,

(6) said heating unit operative for heating air passing from said intake duct to said outlet duct in proportion to the amount of opening of said air mix door,

(7) an air intake door operative in a fresh air position for opening said intake duct to air outside said passenger compartment and operative in a recirculating air position for opening said air intake duct to air inside said passenger compartment,

(8) a passenger compartment air temperature presetting device operative for generating a first signal;

(9) an outside-air temperature sensor operative for generating a second signal;

(10) a passenger compartment air temperature sensor operative for generating a third signal;

(11) an air mix door opening sensor for detecting the amount of opening of the air mix door and for generating a fourth signal corresponding thereto;

(12) a cooling unit actuating switch for detecting whether said cooling unit is in operation and for generating a fifth signal corresponding thereto;

(13) an air intake door switch for detecting the position of said air intake door and generating a sixth signal corresponding thereto;

(14) electronic signal processing means for calculating a target outlet duct air temperature to attain a passenger compartment temperature corresponding to said first signal, and a door control means responsive to said first-sixth signals for generating an air mix door opening amount control signal to control an opening amount of said air mix door,

said door control means including a memory means for storing curves representing a relationship among outlet air duct temperature, air mix door opening percentage, and passenger compartment temperature,

said door control means further including calculating means for calculating from said stored curves an air mix door opening amount for producing said target outlet duct air temperature by linearly interpolating said target outlet duct temperature between a pair of end point duct temperature values corresponding to fully closed and fully opened positions of said air mix door,

to thereby control the temperature within said compartment; and

(15) actuator means responsive to said calculated air mix door opening amount control signal and connected to said air mix door to control the amount of opening of said air mix door.

11. An air conditioning method for an automotive vehicle air conditioning system in which the temperature of air outputted into a passenger compartment is controlled by the opening percentage of an air mix door, which comprises the steps of:

(a) detecting air temperature at a plurality of locations, including a at least outside air temperature T_A and passenger compartment air temperature T_p ;

(b) determining a desired passenger compartment air temperature T_O preset by a passenger compartment air temperature preset device;

(c) calculating a required target outlet duct air temperature T_AC as a function of outside air temperature T_A, passenger compartment air temperature T_p and desired passenger compartment air temperature T_O using a predetermined equation;

(d) determining an air introduction condition selected by a passenger;

(e) storing a plurality of characteristic curves indicative of relationships between outlet duct air temperature T_AC and air mix door opening percentage X with passenger compartment air temperature T_P as a parameter, the characteristic curves being stored corresponding to each air introduction condition;

(f) selecting one of the stored characteristic curves corresponding to the determined air introduction condition, in response to the detected passenger compartment air temperature T_P ;

(g) retrieving from the selected curve the values of a first endpoint outlet duct air temperature T_L representing data obtained when an air mix door is fully closed, and a second endpoint outlet duct air temperature T_H obtained when the air mix door is fully open;

(h) calculating an air mix door opening percentage X on the basis of the current calculated outlet duct air temperature T_AC and in accordance with a linear interpolation between the retrieved first and second endpoint outlet duct air temperatures T_L and T_H ; and

(i) positioning the air mix door in accordance with the calculated air mix door opening percentage X.

12. An air conditioning method for an automotive vehicle air conditioning system in which the temperature of air outputted into a passenger compartment is controlled by the opening percentage of an air mix door, which comprises the steps of:

(a) detecting air temperature at a plurality of locations, including at least outside air temperature T_A and passenger compartment air temperature T_p ;

(b) determining a desired passenger compartment air temperature T_O preset by a passenger compartment air temperature preset device;

(c) calculating a required target outlet duct air temperature T_AC as a function of outside air temperature T_A, passenger compartment air temperature T_p and desired passenger compartment air temperature T_O using a predetermined equation;

(d) determining an air introduction condition selected by the passenger;

(e) calculating an air mix door opening percentage X required to produce outlet duct air at the temperature T_AC by;

storing only the endpoints of a plurality of characteristic curves corresponding to a predetermined relationship between the calculated target value of required duct temperature T_AC together with the determined air introduction condition, and the air mix door opening percentage X,

selecting one of said plurality of stored predetermined characteristic curves in response to the detected passenger compartment air temperature T_p and the determined air introduction condition;

retrieving the values of a first endpoint of the selected curve identifying an outlet duct air temperature T_L obtained when the air mix door is fully closed and a second endpoint of the selected curve, identifying an outlet duct air temperature T_H obtained when the air mix door is fully open, and

calculating the air mix door opening percentage X from the values of the current calculated outlet duct air temperature T_AC, and the retrieved values of said first and a second endpoint outlet duct air temperatures T_L and T_H according to the first equation;

space="preserve" listing-type="equation">X=(1-[T.sub.AC -T.sub.H ]/[T.sub.L -T.sub.H ])×

100%

(f) positioning the air mix door in accordance with the calculated value of X.