Patent Application
20150075822
This disclosure relates to a system that discharges a fire suppression material in the engine compartment of a vehicle in a collision.
Vehicle air conditioning systems circulate a refrigerant through air conditioning lines, a compressor, an evaporator and other components of the air conditioning system. Prior art systems circulated Freon®, non-flamable refrigerants, R134a, CO2, or other types of refrigerants.
Global warming potential (GWP) refrigerants are proposed for use in vehicle HVAC systems that are flammable if exposed to an ignition source with the concentration of the refrigerant within the flammability limits of the GWP refrigerant. The pressure within the HVAC system can expel refrigerant in the engine compartment if the system is compromised in a collision.
This disclosure is directed to the above problems and other problems as summarized below.
According to one aspect of this disclosure, a fire suppression system is provided for an HVAC system for a vehicle. The fire suppression system comprises a refrigerant circulation loop that circulates a flammable refrigerant. A pressure sensor is operatively connected to the circulation loop to sense a reduction in pressure within the loop. A collision sensor is operatively connected to the vehicle to sense the occurrence of a collision. A controller receives a pressure signal from the pressure sensor and a collision signal from the collision sensor. The controller actuates the fire suppression composition distribution system to dispense the fire suppression composition in response to the pressure signal and the collision signal.
According to other aspects of the fire suppression system an optional temperature sensor on the vehicle provides a temperature signal to the controller in addition to the pressure signal and the collision signal before actuating the fire suppression system. The temperature sensor may be an engine coolant temperature sensor or an exhaust gas temperature sensor.
Alternatively, the fire suppression system may include an optional engine load calculating system that receives operating data from the vehicle and calculates a load value representing engine load. The controller receives the engine load value in addition to the pressure signal and the collision signal before actuating the fire suppression system.
The pressure sensor may be an air conditioning pressure switch signal that detects a reduction in the pressure in the circulation loop and sends the pressure signal to the controller. The collision sensor may be a restraints control module that detects a collision and sends the pressure signal to the controller. The collision sensor may be an accelerometer in the restraints control module.
The fire suppression system may include a distribution system that contains the fire suppression composition under pressure, and includes at least one nozzle for dispensing the fire suppression composition in an engine compartment of the vehicle. The fire suppression composition may be a fire retardant chemical, nitrogen gas (N2), or an inert gas.
According to another aspect of this disclosure a method is disclosed for suppressing an engine compartment fire in a vehicle having an HVAC system circulating a flammable refrigerant. The method includes the steps of sensing a pressure value in the HVAC system and providing a pressure signal, sensing a vehicle collision and providing a collision signal. The pressure signal and collision signal are received at a controller and a fire suppressant is discharged into the engine compartment when the rate of change of the pressure signal is below a predetermined rate of change of the pressure value. The rate of change is monitored to avoid discharge of the fire suppression composition if there is only a slow leak.
According to other aspects of the method, a temperature sensor on the vehicle provides a temperature signal in addition to the pressure signal and the collision signal before discharging the fire suppressant. The temperature sensor may be an engine coolant temperature sensor or an exhaust gas temperature sensor.
The method may include the step of calculating an engine load value based upon operating data received from the vehicle. The controller receives the engine load value and compares the engine load value to a predetermined engine load value before discharging the fire suppressant.
The discharging step may further comprise dispensing the fire suppressant through at least one nozzle in an engine compartment of the vehicle. The fire suppressant is a fire retardant chemical or an inert gas.
The aspects of this disclosure as summarized above and other aspects will be described below in greater detail with reference to the attached drawings.
A detailed description of the illustrated embodiments of the present invention is provided below. The disclosed embodiments are examples of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale. Some features may be exaggerated or minimized to show details of particular components. The specific structural and functional details disclosed in this application are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art how to practice the invention.
Referring to
Referring to
If the collision signal is indicated to be received at 28, the controller 20 looks to the pressure signal at 30 and if the pressure signal is received at 30 indicating a rapid loss of pressure from the A/C pressure sensor 24, the controller 20 activates the suppression system at 34. If no pressure signal is received at 30, the controller does not activate the suppression system at 36.
Referring to
Alternatively, an engine load calculation 52 may be developed based upon data provided from the engine control module or other source of data representative of the engine load. From the engine load calculation 52, the controller 46 can infer temperature of the engine compartment 14.
The controller 46 evaluates the under-hood temperature at 54 to determine whether the under-hood temperature is greater than a predetermined temperature TD. If the temperature is not greater than TD, the controller 46 continues to monitor the system. If the under-hood temperatures are greater than TD, the controller then evaluates at 56 whether the rapid reduction in pressure in the air conditioning system indicates that the system is breached. If the air conditioning system is breached, refrigerant may be released from the refrigerant recirculation loop 16 (shown in
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.
