Electric control method for automobile air conditioner

• US 4,316,251 A
• Filed: 10/23/1980
• Issued: 02/16/1982
• Est. Priority Date: 10/02/1978
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Iwata, Yasuhiro, Usami, Kiyoshi, Saito, Atsunori, Naganoma, Masanaori
• Primary Examiner(s): Krass, Errol A.
• Application Number:
  US06/199,920
• Time in Patent Office: 481 Days
• Field of Search: 364/418, 364/424, 364/425, 165/41, 165/42, 237/5, 237/28, 237/32
• US Class Current: 701/36
• CPC Class Codes: B60H 1/00735 Control systems or circuits characterised by their input, i.e. by the detection, measurement or calculation of particular conditions, e.g. signal treatment, dynamic models
• CPC Class Codes: B60H 1/3205 Control means therefor
• 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

In an electric control method for an automobile air conditioner, a digital computer is utilized to calculate a function required to direct the actual in-car temperature toward a desired value in consideration with various changes of ambient temperature and the calculation is compensated to effectively reduce a difference between the actual in-car temperature and the desired value when the rate of change of the actual in-car temperature becomes below a predetermined value.

Claims

1. An electric control method for an automobile air conditioner including an air duct for allowing the flow of air into a passenger compartment of the automobile, an evaporator arranged within said air duct and connected with a refigerant compressor for cooling the air flowing therethrough, a heater arranged within said air duct for warming a portion of the cooled air flowing through said evaporator into said compartment, an air-blend door arranged between said evaporator and said heater for controlling an amount of the cooled air flowing through said heater and controlling an amount of the cooled air directly flowing into said compartment, and control means for controlling the opening degree of said air-blend door to direct the actual in-car temperature toward a desired temperature, said method comprising the steps of:

producing a first electric binary signal indicative of the actual in-car temperature;

producing a second electric binary signal indicative of the actual temperature outside the automobile;

calculating a value indicative of an estimated temperature required to direct the actual in-car temperature toward the desired temperature by a digital computer programmed to calculate said value from a function describing a desired relationship between the estimated temperature and an in-car temperature in consideration with a temperature outside the automobile, the calculation being performed by using the first and second binary signals;

calculating a deviation between the desired temperature and the estimated temperature by said digital computer programmed to calculate the deviation on the basis of the previous calculated value;

producing an output signal from said digital computer when the deviation is out of a first predetermined range and ceasing the output signal when the deviation is in the first predetermined range, the output signal being applied to said control means to direct the actual in-car temperature toward the desired temperature;

discriminating by said digital computer whether or not a difference between the desired temperature and the actual in-car temperature is in a second predetermined range when the rate of change of the actual in-car temperature is below a predetermined value, said digital computer being programmed to perform the discrimination by using the first binary signal;

compensating the estimated temperature to direct the temperature difference into said second predetermined range; and

continuously repeating the above sequence of steps for controlling the actual in-car temperature in response to any changes in said electric binary signals.

2. An electric control method as claimed in claim 1, wherein the function for calculating a value indicative of the estimated temperature is represented as follows:

space="preserve" listing-type="equation">K.sub.1 =k.sub.r ·

T.sub.r +k.sub.am ·

T.sub.am

where;

K₁ is the estimated temperature,

k_r is an in-car temperature coefficient defined by performance of the air conditioner,

k_am is an ambient temperature coefficient defined by performance of the air conditioner,

T_r is the actual in-car temperature, and

T_am is the actual temperature outside the automobile;

and wherein the deviation is represented by the following equation;

space="preserve" listing-type="equation">Δ

K.sub.po =K.sub.2 -K.sub.1

where;

Δ

K_po is the deviation, and

K₂ is the desired temperature.

3. An electric control method for an automobile air conditioner including an air duct for allowing the flow of air into a passenger compartment of the automobile, an evaporator arranged within said air duct and connected with a refrigerant compressor for cooling the air flowing therethrough, a heater arranged within said air duct for warming the air flowing therethrough, control member for controlling a ratio of the cooled air flowing into said compartment against the warmed air flowing into said compartment to maintain the actual in-car temperature in a desired temperature and, an electrically operated clutch means for connecting said compressor to a prime mover of the automobile upon energization thereof and for disconnecting said compressor from said prime mover upon deenergization thereof, said method comprising the steps of:

producing a first electric binary signal indicative of the actual in-car temperature;

producing a second electric binary signal indicative of the actual temperature outside the automobile;

calculating a first difference between the actual in-car temperature and the desired temperature by a digital computer programmed to calculate the first temperature difference by using the first binary signal and to discriminate whether or not the first temperature difference is in a first predetermined range;

calculating a second difference between the desired temperature and the actual temperature outside the automobile by said digital computer, being further programmed to calculate the second temperature difference by using the second binary signal and to discriminate whether or not the second temperature difference is in a second predetermined range broader than the first predetermined range;

producing a first output signal from said computer when either one of the first and second temperature differences is out of the first or second predetermined range and producing a second output signal from said computer when both the first and second temperature differences are in the first and second predetermined ranges respectively; and

energizing said clutch means in response to the first output signal and deenergizing said clutch means in response to the second output signal.

4. An electric control method for an automobile air conditioner including:

an air duct for allowing the flow of air into a passenger compartment of the automobile;

a first switch door arranged within said air duct for selectively allowing the flow of inside air recirculated from the compartment and the flow of outside air from the exterior;

an evaporator arranged within said air duct and connected with a refrigerant compressor for cooling the air flowing through said first switch door;

a heater arranged within said air duct for warming a portion of the cooled air flowing through said evaporator into said compartment;

an air-blend door arranged between said evaporator and said heater for controlling an amount of the cooled air flowing through said heater and controlling an amount of the cooled air directly flowing into said compartment;

control means for controlling the opening angle of said air-blend door to-maintain the actual in-car temperature in a desired temperature;

a second switch door arranged downstream of said heater for discharging the conditioned air into the lower portion of said compartment at its first position and for discharging the conditioned air into the upper portion of said compartment at its second position; and

an electrically operated mechanism for switching-over said second switch door to the second position from the first position upon energization of said mechanism and for switching-over said second switch door to the first position from the second position upon deenergization of said mechanism, the energization of said mechanism being conducted when the actual opening angle of said air-blend door is smaller than a predetermined angle measured from the fully closed position of said air-blend door to isolate said heater from the cooled air, and the deenergization of said mechanism being conducted when the actual opening angle becomes larger than the predetermined angle;

said control method comprising the steps of;

compensating the predetermined angle in relation to changes of the actual in-car temperature and the actual temperature outside the automobile;

producing first and second output signals respectively when the actual opening angle of said air-blend door is smaller than the compensated angle and is larger than the compensated angle; and

selectively conducting energization and deenergization of said electrically operated mechanism in response to the first and second output signals.

5. An electric control apparatus for an automobile comprising an air duct for allowing the flow of air into a passenger compartment of the automobile, an evaporator arranged within said air duct, a refrigerant compressor connected with said evaporator for cooling the air flowing through said air duct, a heater arranged within said air duct for warming a portion of the cooled air flowing through said evaporator into said compartment, an air-blend door arranged between said evaporator and said heater for controlling an amount of the cooled air flowing through said heater and controlling an amount of the cooled air directly flowing into said compartment, control means for controlling the opening degree of said air blend door to direct the actual in-car temperature toward a desired temperature, means for producing a first electric binary signal indicative of the actual in-car temperature, means for producing a second electric binary signal indicative of the actual temperature outside the automobile,

a digital computer for calculating from said first and second binary signals a value indicative of an estimated temperature required to direct the actual in-car temperature toward the desired temperature, said digital computer being programmed to calculate said value from a function describing a desired relationship between the estimated temperature and the in-car temperature in consideration with the actual temperature outside the automobile, said digital computer also being programmed to calculate a deviation between the desired temperature and the estimated temperature on the basis of the previous calculated value,

means for producing an output signal from said digital computer when the deviation is out of a first predetermined range and ceasing the output signal when the deviation is in the first predetermined range, means for applying the output signal to said control means to direct the actual in-car temperature toward the desired temperature, said digital computer being further programmed to use said first binary signal to discriminate whether or not a difference between the desired temperature and the actual in-car temperature is in a second predetermined range when the rate of change of the actual in-car temperature is below a predetermined value, and means for compensating the estimated temperature to direct the temperature difference into the second predetermined range.

6. An electric control apparatus in accordance with claim 5 including an electrically operated clutch means for connecting said refrigerant compressor to a prime mover of the automobile upon energization thereof and for disconnecting said refrigerant compressor from the prime mover upon deenergization thereof, and means for producing output signals from said digital computer for energizing and deenergizing said clutch means.

7. An electric control apparatus for an automobile air conditioner including:

an air duct for allowing the flow of air into a passenger compartment of the automobile;

a first switch door arranged within said air duct for selectively allowing the flow of inside air recirculated from the compartment and the flow of outside air from the exterior;

an evaporator arranged within said air duct and connected with a refrigerant compressor for cooling the air flowing through said first switch door;

a heater arranged within said air duct for warming a portion of the cooled air flowing through said evaporator into said compartment;

an air-blend door arranged between said evaporator and said heater for controlling an amount of the cooled air flowing through said heater and controlling an amount of the cooled air directly flowing into said compartment;

control means for controlling the opening angle of said air-blend door to-maintain the actual in-car temperature in a desired temperature;

a second switch door arranged downstream of said heater for discharging the conditioned air into the lower portion of said compartment at its first position and for discharging the conditioned air into the upper portion of said compartment at its second position; and

an electrically operated mechanism for switching-over said second switch door to the second position from the first position upon energization of said mechanism and for switching-over said second switch door to the first position from the second position upon deenergization of said mechanism, the energization of said mechanism being conducted when the actual opening angle of said air-blend door is smaller than a predetermined angle measured from the fully closed position of said air-blend door to isolate said heater from the cooled air, and the deenergization of said mechanism being conducted when the actual opening angle becomes larger than the predetermined angle;

means for compensating the predetermined angle in relation to changes of the actual in-car temperature and the actual temperature outside the automobile;

means for producing first and second output signals respectively when the actual opening angle of said air-blend door is smaller than the compensated angle and is larger than the compensated angle; and

means for selectively conducting energization and deenergization of said electrically operated mechanism in response to the first and second output signals.

8. An electric control method of controlling an automobile air conditioner including an air duct for allowing the flow of air into a passenger compartment of the automobile, an evaporator arranged within said air duct and connected with a refrigerant compressor for cooling the air flowing therethrough, a heater arranged within said air duct for warming a portion of the cooled air flowing therethrough from said evaporator into said compartment, an airblend door arranged between said evaporator and said heater for controlling an amount of the cooled air flowing through said heater and controlling an amount of the cooled air directly flowing into said compartment, and control means for controlling the opening degree of said air-blend door to direct the actual in-car temperature toward a desired temperature, said method comprising the steps of:

(a) producing a first electric signal indicative of the actual in-car temperature;

(b) producing a second electric signal indicative of the outside ambient temperature;

(c) producing a third electric signal indicative of the desired temperature;

(d) calculating a value indicative of an estimated in-car temperature (K₁) based on a function (K₁ =f(T_r, T_am, C_F)) describing a desired relationship among the estimated in-car temperature, the actual in-car temperature, the outside ambient temperature, and a variable C_F indicative of fluctuation of the heat load in the passenger compartment, the calculation being performed by using the first and second electric signals;

(e) calculating a deviation between the desired temperature and the calculated value of the estimated in-car temperature (K₁) by using the third electric signal;

(f) producing an output signal when the deviation is out of a first predetermined range and ceasing the output signal when the deviation is in the first predetermined range, the output, signal being applied to said control means to direct the actual in-car temperature toward the desired temperature;

(g) discriminating a difference between the desired temperature and the actual in-car temperature in relation to a second predetermined range when the rate of change of the actual in-car temperature is below a predetermined value;

(h) compensating the variable (C_F) of said function in a value necessary for directing the temperature difference into said second predetermined range when the temperature difference is out of said second predetermined range; and

(i) continuously repeating the above sequence of steps of controlling the actual in-car temperature in response to any change of the electric signals.

9. An electric control method as claimed in claim 8, wherein said function for calculating a value indicative of the estimated in-car temperature is represented as follows:

space="preserve" listing-type="equation">K.sub.1 =k.sub.r T.sub.r +k.sub.am T.sub.am C.sub.F

where;

K₁ is the estimated in-car temperature,

k_r is an in-car temperature coefficient defined by performance of the air conditioner,

k_am is an outside ambient temperature coefficient defined by performance of ;

the air conditioner,

T_r is the actual in-car temperature,

T_am is the outside ambient temperature, and

C_F is the variable;

and wherein the deviation is represented by the following equation;

space="preserve" listing-type="equation">K.sub.po +K.sub.2 -K.sub.1

where;

K_po is the deviation, and K₂ is the desired temperature.