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  Variable capacity compressor control apparatus for vehicleUSPTO Application #: 20070012056Title: Variable capacity compressor control apparatus for vehicle Abstract: A variable capacity compressor control apparatus includes a variable capacity compressor equipped with a control valve, a valve controller connected to the control valve to determine its opening/closing duty ratio and output a compression-ratio control signal for driving the control valve with the opening/closing duty ratio determined, a flow meter arranged in a refrigerant pipe connected to the variable capacity compressor to detect a flow rate of the refrigerant for the air conditioner flowing into the variable capacity compressor, a signal processing unit connected to the flow meter to generate a flow-rate control signal based on the present flow rate of the refrigerant detected by the flow meter, the signal processing unit inputting the compression-ratio control signal outputted from the valve controller to generate a valve control signal formed by the flow-rate control signal and the compression-ratio control signal to the control valve, and an outside control unit configured to input a driving condition of the vehicle and output a demand of reducing a driving torque of the variable capacity compressor to the signal processing unit when the present driving condition satisfies a predetermined condition. (end of abstract)
Agent: Foley And Lardner LLP Suite 500 - Washington, DC, US Inventor: Hiroyuki Makishima USPTO Applicaton #: 20070012056 - Class: 062228100 (USPTO) Related Patent Categories: Refrigeration, Automatic Control, Refrigeration Producer, Compressor Or Its Drive Controlled The Patent Description & Claims data below is from USPTO Patent Application 20070012056. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a variable capacity compressor control apparatus for controlling a variable capacity compressor for a vehicle. [0003] 2. Description of Related Art [0004] Japanese Patent Application Laid-open Nos. 2000-317467, 2003-90284 and 2003-278660 disclose a refrigerant circulation circuit for an automotive air conditioner commonly. In Japanese Patent Application Laid-open No. 2000-317467, as shown in FIG. 1, the disclosed refrigerant circulation circuit comprises a compressor module CPM having a compressor CP and an outside refrigerant circuit 101. The outside refrigerant circuit 101 includes a condenser 102, an expansion valve 103 and an evaporator 104. In constituents of the compressor CP, a discharge chamber 107 is communicated with the condenser 102 through a communication pipe 108. A fixed choke 108a is interposed in the communication pipe 108. This compressor CP is a type of variable capacity by controlling pressure in a crank chamber 115. For this, the compressor module CPM is provided with a control valve 132 for controlling the pressure in the crank chamber 115 and a compressor ECU (Electronic Control Unit) 177. In order to allow the compressor CP to operate at torque corresponding to a torque setting command from an air-conditioner ECU 180 or an engine ECU 190, the compressor ECU 177 controls an opening degree of the control valve 132, so that the discharge flow rate of the compressor CP is changed to a value corresponding to a desired setting torque. Thus, since the engine ECU 190 dose not estimate a load torque on the compressor CP but employs a value of the load torque as engine control data, there is no need to prepare an estimation map for load torque with respect to each type of vehicle. [0005] In the above-mentioned conventional automotive air conditioner, however, the driving torque of the compressor CP is controlled by altering control signals transmitted from the air-conditioner ECU 180 to the control valve 132 forcibly. Therefore, there is a tendency that during the control of the driving torque of the compressor CP, its amenity is damaged. Additionally, due to controlling of the discharge flow only, there is a possibility that a change in compression ratio causes abrupt torque fluctuations. SUMMARY OF THE INVENTION [0006] In the above-mentioned situation, it is an object of the present invention to provide a variable capacity compressor control apparatus which is capable of controlling its driving torque without producing such abrupt torque fluctuations. [0007] In order to attain the above object, according to the first aspect of the invention, there is provided a variable capacity compressor control apparatus for a vehicle, comprising: a variable capacity compressor equipped with a control valve capable of changing a discharge volume of a refrigerant for an air conditioner therefrom; a valve control unit electrically connected to the control valve to determine an opening/closing duty ratio thereof on a basis of a preset in-cabin target temperature and various air conditioning parameters and output a compression-ratio control signal for driving the control valve with the opening/closing duty ratio determined; a flow meter arranged in a refrigerant pipe connected to the variable capacity compressor to detect a flow rate of the refrigerant for the air conditioner flowing into the variable capacity compressor; a signal processing unit electrically connected to the flow meter and the valve control unit to generate a flow-rate control signal based on the present flow rate of the refrigerant detected by the flow meter, the signal processing unit inputting the compression-ratio control signal outputted from the valve control unit and outputting a valve control signal formed by the flow-rate control signal and the compression-ratio control signal to the control valve; and an outside control unit electrically connected to the signal processing unit to input a driving condition of the vehicle and output a demand of reducing a driving torque of the variable capacity compressor to the signal processing unit when the present driving condition satisfies a predetermined condition, wherein when the demand of reducing the driving torque is outputted from the outside control unit, the signal processing unit modulates the flow-rate control signal, thereby changing the valve control signal. [0008] According to the second aspect of the invention, the compression-ratio control signal is a signal in the form of PWM control. [0009] According to the third aspect of the invention, the control valve of the variable capacity compressor comprises: a suction pressure detecting section communicated with a suction chamber of the variable capacity compressor to detect a suction-side pressure Ps of refrigerant sucked into the variable capacity compressor; a discharge pressure detecting section communicated with a discharge chamber of the variable capacity compressor to detect a discharge-side pressure Pd of the refrigerant discharged from the variable capacity compressor; a crank-chamber communicating section communicated with a crank chamber of the variable capacity compressor; a pressure regulating passage formed to communicate the crank-chamber communicating section with the discharge pressure detecting section; a valve section having a valve body movably arranged in the pressure regulating passage and configured to open and close the pressure regulating passage with movements of the valve body in the pressure regulating passage; a pressure regulating spring which is responsive of the suction-side pressure Ps thereby to open and close the valve section; a suction-pressure-chamber communicating passage formed to communicate the suction pressure detecting section with the discharge pressure detecting section; and a driving section electrically connected to the signal processing section to actuate the valve body of the valve section thereby opening and closing the pressure regulating passage. [0010] According to the fourth aspect of the invention, the outside control unit is an engine control unit for controlling a driving source of the vehicle. [0011] According to the fifth aspect of the invention, when the demand of reducing the driving torque is outputted from the outside control unit, the signal processing unit modulates the flow-rate control signal so as to reduce a voltage of the valve control signal. [0012] According to the sixth aspect of the invention, when the demand of reducing the driving torque is outputted from the outside control unit, the signal processing unit modulates the flow-rate control signal so as to reduce a pulse width of the valve control signal. [0013] These and other objects and features of the present invention will become more fully apparent from the following description and appended claims taken in conjunction with the accompany drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0014] FIG. 1 is a schematic view showing the constitution of a conventional apparatus; [0015] FIG. 2 is a schematic view of an air conditioner for a vehicle, showing one embodiment of the present invention; [0016] FIG. 3 is a circuit diagram showing the constitution of a flow meter on which the embodiment of the present invention is applied; [0017] FIG. 4 is a time chart showing the operating characteristics of a variable capacity compressor in case of controlling its refrigerant flow rate by reducing voltage of control signals applied on a driving part of the compressor through flow control signals; and [0018] FIG. 5 is another time chart showing the operating characteristics of the variable capacity compressor in case of controlling its refrigerant flow rate by reducing pulse-width of control signals applied on the driving part of the compressor through flow control signals. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0019] Referring to the accompanying drawings, a variable capacity compressor in accordance with an embodiment of the present invention and a control method of controlling the variable capacity compressor will be described below. [0020] [Constitution of Air Conditioner for Vehicle] Continue reading... Full patent description for Variable capacity compressor control apparatus for vehicle Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Variable capacity compressor control apparatus for vehicle patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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