Controlling the airflow rate in an air conditioner

• US 4,580,620 A
• Filed: 04/30/1985
• Issued: 04/08/1986
• Est. Priority Date: 10/30/1981
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Jukogyo Kabushiki Kaisha (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Mitsubishi Jukogyo Kabushiki Kaisha (Mitsubishi Heavy Industries, Ltd.)
• Inventors: Yoshida, Yukio, Akimoto, Ryosaku, Fukumoto, Ryutaro
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Smith, Randolph A.
• Application Number:
  US06/728,162
• Time in Patent Office: 343 Days
• Field of Search: 165/12, 165/16, 165/23, 165/26, 165/39, 165/40, 165/42, 236/49
• 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: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 2011/0002 for admittance of outside air
• CPC Class Codes: F24F 2110/10 Temperature
• CPC Class Codes: G05D 23/1917 using digital means
• CPC Class Codes: G05D 23/24 the sensing element having a resistance varying with temperature, e.g. a thermistor

Abstract

In an air conditioner, the control of the airflow rate is effected by utilizing both the temperature deviation between the room temperature and a set temperature and an air-mix damper position as a proportional control factor with the airflow rate compensation being based on an incremental integer control factor which has been derived from the temperature deviation.

Claims

1. A method for controlling the airflow rate in an air-mix type air conditioner for use in vehicles comprising a fan, a cooler for cooling air blown out of said fan, a heater for heating at least a portion of a cold airflow cooled by said cooler and an air-mix damper for controlling the temperature of the blown-out air by regulating the proportion between a flow rate of the air passing through said heater and a flow rate of the air by-passing said heater and for effecting temperature control by automatically controlling the position of said air-mix damper by utilizing a room temperature, a set temperature and the position of the air-mix damper as inputs, wherein, based upon the position of the air-mix damper and the temperature difference DT between the room temperature and the set temperature:

when the air-mix damper is positioned at a MAX COOL position, if the temperature difference DT is positive, the airflow rate of the fan is gradually increased, whereas if the temperature difference DT is negative, the airflow rate of the fan is gradually decreased;

when the air-mix damper is positioned at a MAX HOT position, if the temperature different DT is negative, the airflow rate of the fan is gradually increased, whereas if the temperature difference DT is positive, the airflow rate of the fan is gradually decreased; and

when the air-mix damper is positioned in an intermediate position which is between the MAX COOL and MAX HOT positions, regardless of the value of the temperature difference DT, the airflow rate of the fan is gradually decreased until a point at which the airflow rate of the fan is adjusted so as to be proportional to the absolute value of the temperature difference DT.