Automatic air conditioner system with variable displacement compressor for automotive vehicles

• US 4,928,499 A
• Filed: 03/29/1989
• Issued: 05/29/1990
• Est. Priority Date: 03/31/1988
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Sakamoto, Hideyuki, Nose, Toshimitsu, Kiminami, Ikuo
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US07/330,259
• Time in Patent Office: 426 Days
• Field of Search: 62/228.5, 62/163, 62/186, 98/2.01, 165/43, 165/24
• US Class Current: 62/186
• 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: F25B 49/022 Compressor control arrangements

Abstract

An automatic air conditioning system for automotive vehicles with a variable displacement compressor comprises a sensor for detecting an intake air temperature of air flowing through an evaporator placed just behind the evaporator, a control valve for essentially changing the discharge volume of the compressor on the basis of the difference between the intake air temperature and its target value, and a CPU for deriving the different target values in response to two modes, namely a BI-LEVEL mode wherein conditioned air is simultaneously discharged from both upper and lower discharge outlets, and a MONO-LEVEL mode wherein conditioned air is discharged from either the upper or lower discharge outlets. The control valve operates in such a manner that, when the difference is plus, that is, the intake air temperature is higher than the target value, the discharge volume is essentially increased, and when the difference is minus, that is, the intake air temperature is lower than the target value, the discharge volume is essentially decreased. Thus, in the BI-LEVEL mode the amount of air reheated by a heater unit becomes larger than the amount of reheated air in the MONO-LEVEL mode. According to the invention, the BI-LEVEL mode effect can be sufficiently satisfied, particalarly, in a fuel-saving mode wherein the difference between the intake air temperature and the temperature of air to be discharged from the discharge outlets is very small.

Claims

1. An automatic air conditioning system for automotive vehicles with a variable displacement compressor comprising:

first detecting means for detecting an intake air temperature defined by a temperature of air flowing through an evaporator of said air conditioning system placed just behind said evaporator;

discharge changing means for essentially changing the discharge volume of refrigerant discharged from said compressor on the basis of the difference between said intake air temperature and its target value;

mode signal generating means for generating a mode signal representing whether said air conditioning system is operated in a first mode wherein conditioned air is simultaneously discharged from both of upper and lower discharge outlets or is operated in a second mode wherein conditioned air is discharged from either the upper or lower of said discharge outlets; and

target value deriving means for deriving said target value of said intake air temperature on the basis of said mode signal in such a manner that said target value in said first mode is smaller than said target value in said second mode.

2. An automotive air conditioning system for automotive vehicles as set forth in claim 1, wherein said discharge changing means operates in such a manner that, when said intake air temperature is higher than said target value, the discharge volume is essentially increased, and when said intake air temperature is lower than said target value, the discharge volume is essentially decreased.

3. An automatic air conditioning system for automotive vehicles as set forth in claim 1, further comprising:

second detecting means for detecting a physical quantity indicative of environmental condition in and around the automotive vehicle; and

calculating means for calculating a target discharge air temperature, to be discharged from said discharge outlets, on the basis of said physical quantity and a preset temperature input from temperature setting means for setting a desirable room temperature in the vehicular cabin.

4. An automatic air conditioning system for automotive vehicles as set forth in claim 3, wherein said physical quantity is ambient temperature, magnitude of insolation, and/or room temperature in the vehicular cabin.

5. An automatic air conditioning system for automotive vehicles as set forth in claim 4, wherein said target value deriving means appropriately selects said target value of said intake air temperature in accordance with said target discharge air temperature.

6. An automatic air conditioning system for automotive vehicles comprising:

discharge means for compressing and discharging refrigerant;

discharge changing means for changing discharge volume of the refrigerant discharged from said discharge means;

mode signal generating means for generating a mode signal representing whether said air conditioning system is operated in a first mode wherein conditioned air is simultaneously discharged from both upper and lower discharge outlets or is operated in a second mode wherein conditioned air is discharged from either the upper or lower of said discharge outlets;

first detecting means for detecting an intake air temperature defined by a temperature of air flowing through an evaporator of said air conditioning system placed just behind said evaporator;

second detecting means for detecting a physical quantity indicative of environmental conditions in and around the automotive vehicle;

calculating means for calculating a target discharge air temperature, to be discharged from said discharge outlets, on the basis of said physical quantity and a preset temperature input from temperature setting means for setting a desirable room temperature in the vehicular cabin.

target value deriving means for deriving an individual target value of said intake air temperature in accordance with said target discharge air temperature in such a manner that said target value in said first mode is smaller than said target value in said second mode; and

control means capable of controlling said discharge changing means on the basis of the difference between said intake air temperature and said target value in such a manner that, when said target value is lower than said intake air temperature, the discharge volume of said discharging means is essentially increased depending on the difference, and when said target value is higher than said intake air temperature, the discharge of said discharging means is essentially decreased depending on the difference.

7. An automatic air conditioning system for automotive vehicles as set forth in claim 6, wherein said physical quantity is ambient temperature, magnitude of insolation, and/or room temperature in the vehicular cabin.