Leakage monitoring of air conditioning systems

Abstract

A device for detecting a leakage in a motor vehicle air conditioning system that utilizes carbon dioxide as the cooling material is provided. The device for detecting leakage includes: at least one sensor for rapid detection of especially high rate of increase of the carbon dioxide concentration and/or particularly high carbon dioxide concentration in the air of the passenger compartment; an evaluation device for evaluating the ascertained rate of increase and/or concentration; and at least one actuator which, in the case that the rate of increase and/or concentration exceeds a threshold value, performs a remedial action. The remedial action includes: carrying out forced ventilation measures of the passenger compartment; closing the ventilation channels that lead into the inner space of the vehicle; and/or separating off that part of the air conditioning system which is in contact with the air in the passenger compartment from the part of the air conditioning system that is not in contact with the air in the passenger compartment.

What is claimed is:  
     
         1 . A device for detecting a leakage in a motor vehicle air conditioning system that utilizes carbon dioxide as the cooling medium, comprising: 
 at least one sensor for detection of at least one of carbon dioxide concentration and a rate of increase of carbon dioxide concentration in air in a passenger compartment of the motor vehicle;    an evaluation device for determining at least one of whether the carbon dioxide concentration exceeds a first threshold value and whether the rate of increase of the carbon dioxide concentration exceeds a second threshold; and    at least one actuator for triggering, if at least one of the carbon dioxide concentration exceeds the first threshold value and the rate of increase of the carbon dioxide exceeds the second threshold value, at least one of: 
 forced ventilation of the passenger compartment;  
 closing of a ventilation channel that leads into the passenger compartment; and  
 separating a part of the air conditioning system that is in contact with the air in the passenger compartment from a part of the air conditioning system that is not in contact with the air in the passenger compartment.  
   
     
     
         2 . The device as recited in  claim 1 , wherein the sensor is a photometric sensor.  
     
     
         3 . The device as recited in  claim 1 , wherein the sensor is a micromechanical sensor.  
     
     
         4 . The device as recited in  claim 1 , wherein the sensor has a detection sensitivity for detecting a carbon dioxide concentration in the air in the passenger compartment that impairs at least one of health and driving attention of a driver.  
     
     
         5 . The device as recited in  claim 1 , wherein the sensor has a sensitivity for detecting, within a period of approximately 10 seconds, a carbon dioxide concentration of approximately 0.5 volume-percent in the air in the passenger compartment.  
     
     
         6 . The device as recited in  claim 1 , wherein the sensor has a sensitivity for detecting a carbon dioxide concentration of at least up to approximately 3 volume-percent in the air in the passenger compartment.  
     
     
         7 . The device as recited in  claim 1 , wherein the forced ventilation is achieved by at least one of: 
 opening at least one window by a window lift;    opening a sliding roof of the vehicle; and    opening a convertible top of the vehicle.    
     
     
         8 . The device as recited in  claim 1 , wherein the ventilation channel that leads into the passenger compartment of the vehicle is closed at a location where an evaporator of the air conditioning system is operatively coupled to the ventilation channel, whereby the evaporator is no longer in contact with the air in the passenger compartment.  
     
     
         9 . The device as recited in  claim 1 , wherein an evaporator is the part of the air conditioning system that is in contact with the air in the passenger compartment, and wherein the evaporator is segmented by at least one control valve, whereby the evaporator is separated from the part of the air conditioning system that is not in contact with the air in the passenger compartment, by the closing of the control valve.  
     
     
         10 . The device as recited in  claim 1 , further comprising a warning mechanism, wherein if at least one of the carbon dioxide concentration exceeds the first threshold value and the rate of increase of the carbon dioxide concentration exceeds the second threshold value, the warning mechanism outputs a warning notice to the driver.  
     
     
         11 . The device as recited in  claim 1 , wherein the sensor is a micromechanical heat conductivity sensor.  
     
     
         12 . A method for detecting a leakage in a motor-vehicle air-conditioning system that utilizes carbon dioxide as the cooling medium, comprising: 
 detecting, using at least one sensor, at least one of carbon dioxide concentration and a rate of increase of carbon dioxide concentration inside a passenger compartment of the motor vehicle;    determining, using an evaluation device, whether the at least one of carbon dioxide concentration and the rate of increase of carbon dioxide concentration inside the passenger compartment exceeds a respective threshold value; and    performing at least one of a plurality of remedial measures if the at least one of carbon dioxide concentration and the rate of increase of carbon dioxide concentration inside the passenger compartment exceeds the respective threshold value, wherein the remedial measures include; 
 performing a forced ventilation of the passenger compartment;  
 closing a ventilation channel that leads into the passenger compartment; and  
 separating a part of the air conditioning system that is in contact with the air in the passenger compartment from a part of the air conditioning system that is not in contact with the air in the passenger compartment.  
   
     
     
         13 . The method as recited in  claim 12 , wherein the forced ventilation is achieved by at least one of: 
 opening at least one window by a window lift;    opening a sliding roof of the vehicle; and    opening a convertible top of the vehicle.