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.

1 . 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.    
   
   
       2 . The variable capacity compressor control apparatus of  claim 1 , wherein the compression-ratio control signal is a signal in the form of PWM control.  
   
   
       3 . The variable capacity compressor control apparatus of  claim 1 , wherein 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.    
   
   
       4 . The variable capacity compressor control apparatus of  claim 1 , wherein the outside control unit is an engine control unit for controlling a driving source of the vehicle.  
   
   
       5 . The variable capacity compressor control apparatus of  claim 1 , 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 so as to reduce a voltage of the valve control signal.  
   
   
       6 . The variable capacity compressor control apparatus of  claim 1 , 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 so as to reduce a pulse width of the valve control signal.