Hybrid compressor system

Abstract

A hybrid compressor system in a vehicle air conditioner includes a variable displacement hybrid compressor, a detector for detecting information for air conditioning, a thermal load calculator and a controller. The compressor is selectively driven by an engine and an electric motor. The calculator calculates a thermal load based on the detected information. The controller compares the thermal load with a predetermined value. The controller changes displacement of the compressor to a first predetermined displacement value and selects the engine as a drive source of the compressor when the thermal load is larger than the predetermined value. The controller changes the displacement of the compressor to a second predetermined displacement value that is smaller than the first predetermined displacement value and selects the electric motor as the drive source of the compressor when the thermal load is equal to, or smaller than the predetermined value.

What is claimed is:  
     
         1 . A hybrid compressor system in use for a vehicle air conditioner comprising: 
 a variable displacement hybrid compressor for compressing refrigerant;    a drive source for driving a vehicle operatively connected to the compressor;    an electric motor operatively connected to the compressor, the compressor being selectively driven by one of the drive source for driving the vehicle and the electric motor;    an air conditioning information detector for detecting information for air conditioning;    a thermal load calculator electrically connected to the air conditioning information detector, the thermal load calculator calculating a thermal load based on the detected information from the air conditioning information detector; and    a controller electrically connected to the thermal load calculator, the controller comparing the thermal load with a predetermined value, the controller changing displacement of the compressor to a first predetermined displacement value and selecting the drive source for driving the vehicle as a drive source of the compressor when the thermal load is larger than the predetermined value, the controller changing the displacement of the compressor to a second predetermined displacement value and selecting the electric motor as the drive source of the compressor when the thermal load is equal to, or smaller than the predetermined value, the second predetermined displacement value being smaller than the first predetermined displacement value.    
     
     
         2 . The hybrid compressor system according to  claim 1 , wherein the drive source for driving the vehicle is an engine.  
     
     
         3 . The hybrid compressor system according to  claim 2 , wherein the controller changes the displacement of the compressor to the second predetermined displacement value and selects the electric motor as the drive source of the compressor when the thermal load is equal to, or smaller than the predetermined value and when the engine is in a stopped state, the controller selecting the engine as the drive source of the compressor when the thermal load is equal to, or smaller than the predetermined value and when the engine is in a running state.  
     
     
         4 . The hybrid compressor system according to  claim 3 , further comprising a residual quantity detector for detecting a residual quantity of a battery for the electric motor, the residual quantity detector providing the detected residual quantity of the battery to the controller, the controller comparing the detected residual quantity of the battery with a predetermined quantity, wherein the controller changes the displacement of the compressor to the second predetermined displacement value and selects the electric motor as the drive source of the compressor when the thermal load is equal to, or smaller than the predetermined value, when the engine is in the running state, and when the detected residual quantity of the battery is equal to, or larger than the predetermined quantity, the controller selecting the engine as the drive source of the compressor when the thermal load is equal to, or smaller than the predetermined value, when the engine is in the running state, and when the detected residual quantity of the battery is smaller than the predetermined quantity.  
     
     
         5 . The hybrid compressor system according to  claim 3 , wherein the controller changes the displacement of the compressor to the second predetermined displacement value and selects the engine as the drive source of the compressor when the thermal load is equal to, or smaller than the predetermined value and when the engine is in the running state.  
     
     
         6 . The hybrid compressor system according to  claim 2 , wherein the compressor comprises: 
 a housing; and    one of a speed increasing mechanism provided in the housing for increasing a rotational speed obtained from the engine and a speed reducing mechanism provided in the housing for decreasing a rotational speed obtained from the electric motor.    
     
     
         7 . The hybrid compressor system according to  claim 6 , wherein the electric motor is provided in the housing and includes a stator, one of the speed increasing mechanism and the speed reducing mechanism being arranged inside the stator.  
     
     
         8 . The hybrid compressor system according to  claim 2 , wherein the first predetermined displacement value is a maximum value, the second predetermined displacement value being a minimum value, the displacement of the compressor being switched between the maximum value and the minimum value.  
     
     
         9 . The hybrid compressor system according to  claim 2 , wherein the compressor is a scroll type.  
     
     
         10 . The hybrid compressor system according to  claim 2 , wherein the electric motor is formed without a permanent magnet.  
     
     
         11 . The hybrid compressor system according to  claim 2 , wherein the controller controls a rotational speed of the electric motor in accordance with the thermal load when the electric motor drives the hybrid compressor.  
     
     
         12 . The hybrid compressor system according to  claim 2 , wherein the information includes a temperature in a vehicle compartment.  
     
     
         13 . A control system for a variable displacement hybrid compressor in a vehicle air conditioner having two drive sources including an engine for driving a vehicle and an electric motor, the hybrid compressor being selectively driven by one of the engine and the electric motor, the control system comprising: 
 an air conditioning information detector for detecting information for air conditioning;    a thermal load calculator electrically connected to the air conditioning information detector, the thermal load calculator calculating a thermal load based on the detected information from the air conditioning information detector; and    a controller electrically connected to the thermal load calculator, the controller comparing the thermal load with a predetermined value, the controller changing displacement of the compressor to a first predetermined displacement value and selecting the engine as a drive source of the compressor when the thermal load is larger than the predetermined value, the controller changing the displacement of the compressor to a second predetermined displacement value and selecting the electric motor as the drive source of the compressor when the thermal load is equal to, or smaller than the predetermined value, the second predetermined displacement value being smaller than the first predetermined displacement value.    
     
     
         14 . A method for controlling a hybrid compressor system in use for a vehicle air conditioner, the hybrid compressor system having a variable displacement hybrid compressor and two drive sources including an engine for driving a vehicle and an electric motor, the hybrid compressor being selectively driven by one of the engine and the electric motor, the method comprising the steps of: 
 (a) switching on the air conditioner;    (b) detecting information for air conditioning;    (c) calculating a thermal load based on the detected information;    (d) comparing the thermal load with a predetermined value;    (e) selecting the drive source of the compressor based on the comparison; and    (f) changing displacement of the compressor based on the selection.    
     
     
         15 . The method according to  claim 14 , wherein step (e) includes the steps of: 
 (g) selecting the engine as a drive source of the compressor when the thermal load is larger than the predetermined value; and    (h) selecting the electric motor as the drive source of the compressor when the thermal load is equal to, or smaller than the predetermined value.    
     
     
         16 . The method according to  claim 15 , wherein step (f) includes the steps of: 
 (i) changing the displacement of the compressor to a maximum value when the thermal load is larger than the predetermined value; and    (j) changing the displacement of the compressor to a minimum value when the thermal load is equal to, or smaller than the predetermined value.    
     
     
         17 . The method according to  claim 15 , further comprising the step of 
 (k) judging whether the engine is in a running state after step (d) when the thermal load is equal to, or smaller than the predetermined value.    
     
     
         18 . The method according to  claim 17 , wherein step (h) includes the steps of: 
 (l) selecting the engine as the drive source of the compressor when the engine is in the running state; and    (m) selecting the electric motor as the drive source of the compressor when the engine is in a stopped state.    
     
     
         19 . The method according to  claim 18 , further comprising the steps of: 
 (n) detecting residual quantity of a battery for the electric motor after step (k) when the engine is in the running state; and    (o) comparing the detected residual quantity with a predetermined quantity.    
     
     
         20 . The method according to  claim 19 , wherein step (I) includes the steps of: 
 (p) selecting the electric motor as the drive source of the compressor when the residual quantity is equal to, or larger than the predetermined quantity; and    (q) selecting the engine as the drive source of the compressor when the residual quantity is smaller than the predetermined quantity.    
     
     
         21 . The method according to  claim 15 , further comprising the steps of: 
 (r) judging whether the engine is in a running state after step (g); and    (s) starting the engine when the engine is in a stopped state.