PREVENTING THE FORMATION OF BLACK ICE AS A RESULT OF EXHAUST WATER FROM MOTOR VEHICLES

Abstract

A hydrogen fuel cell vehicle system and method inhibit formation of black ice on road surfaces at low temperatures as a result of exhaust water by treating the exhaust water prior to discharge with a deicing or antifreeze substance to lower the freezing point of the water. A metering device may meter a deicing or antifreeze substance, such as sodium chloride, calcium chloride, urea, or the like to be dissolved in the exhaust water that is produced during the production of energy. The vehicle may include a bypass valve that selectively bypasses the water treatment system when ambient conditions are not conducive to ice formation. The bypass valve is operated to direct exhaust flow to a condenser and water treatment system when ambient conditions are favorable to ice formation, with the deicing or antifreeze substance metered based on current or predicted ambient or road surface conditions.

Claims

1. A vehicle comprising: a hydrogen fuel cell; an exhaust pipe configured to receive water vapor produced by the hydrogen fuel cell; a condenser coupled to the exhaust pipe and configured to condense the water vapor from the hydrogen fuel cell to liquid water; and a metering device associated with the condenser and configured to deliver a substance for mixing with the liquid water that lowers a freezing temperature of the liquid water prior to discharging of the liquid water from the exhaust pipe.

2. The vehicle of claim 1 wherein the substance comprises a salt.

3. The vehicle of claim 2 wherein the substance comprises sodium chloride.

4. The vehicle of claim 1 further comprising: a bypass valve configured to selectively direct the water vapor to the condenser in response to ambient conditions satisfying criteria associated with icing of a road surface.

5. The vehicle of claim 4 wherein the ambient conditions comprise ambient temperature.

6. The vehicle of claim 5 further comprising an ambient temperature sensor configured to measure the ambient temperature.

7. The vehicle of claim 1 wherein the metering device is configured to meter the substance for mixing with the liquid water in response to a volume of the liquid water and ambient temperature.

8. The vehicle of claim 1 wherein the metering device delivers an amount of the substance for mixing with the liquid water based on ambient temperature.

9. The vehicle of claim 1 further comprising a valve coupled to the exhaust pipe and configured to deliver a mixture of the liquid water and the substance to the exhaust pipe.

10. A vehicle comprising: a power plant that provides propulsive force for the vehicle and generates water vapor during operation; an exhaust configured to receive the water vapor generated by the power plant; a bypass valve coupled to the exhaust; a condenser coupled to the bypass valve and configured to condense the water vapor from the exhaust to liquid water; a metering device configured to deliver a substance for mixing with the liquid water that lowers a freezing temperature of the liquid water; and a valve positioned downstream of the metering device and configured to direct a mixture of the liquid water and the substance into the exhaust prior to discharge of the mixture to atmosphere.

11. The vehicle of claim 10 wherein the bypass valve directs the water vapor to the condenser in response to ambient temperature being below an associated threshold.

12. The vehicle of claim 11 wherein the bypass valve directs the water vapor to atmosphere in response to ambient temperature not being below the associated threshold.

13. The vehicle of claim 10 wherein the metering device is controlled to deliver an amount of the substance in response to ambient temperature.

14. The vehicle of claim 10 further comprising a reservoir configured to hold the liquid water, wherein the metering device delivers the substance to the reservoir.

15. The vehicle of claim 10 further comprising an ambient temperature sensor.

16. A method for controlling a vehicle having a hydrogen fuel cell, comprising: selectively directing water vapor from the hydrogen fuel cell to a condenser to condense the water vapor to liquid water in response to ambient temperature being below an associated threshold and adding a substance to the liquid water to lower freezing temperature of the liquid water prior to discharge from the vehicle.

17. The method of claim 16 further comprising metering an amount of the substance in response to ambient temperature to vary the amount of the substance added to the liquid water, wherein the amount increases as the ambient temperature decreases.

18. The method of claim 16 further comprising directing the water vapor from the hydrogen fuel cell to atmosphere in response to the ambient temperature not being below the associated threshold.

19. The method of claim 16 wherein the substance comprises a salt.

20. The method of claim 19 wherein the substance comprises sodium chloride.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 is a block diagram of a representative vehicle system having a deicing or antifreeze substance metering device for treating water generated by the vehicle prior to discharge according to various embodiments of the disclosure.

DETAILED DESCRIPTION

[0023] As required, detailed embodiments are disclosed herein; however, it is to be understood that the disclosed embodiments are merely representative of the claimed subject matter, which 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. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ embodiments of the claimed subject matter.

[0024] FIG. 1 is a block diagram of a fuel cell vehicle 1 having a discharge water deicing or antifreeze system according to various embodiments of the disclosure. The fuel cell vehicle 1 comprises a fuel cell 2 that is supplied with hydrogen from a storage vessel 3 and with compressed air (oxygen) from a compressor 4.

[0025] The exhaust air including water vapor is discharged in an exhaust air pipe 10 that conducts the exhaust air out to the environment. A condenser 5 is arranged upstream of the outlet with the result that the water vapor condenses to exhaust water.

[0026] A deicing or antifreeze substance is added to this exhaust water by means of a metering unit 6 prior to said exhaust water being discharged via a valve 7 into the environment. In various embodiments, the deicing or antifreeze substance is cooking salt or sodium chloride, which may be in solid (dry) form or dissolved in a saturated solution, for example. To determine the quantity of deicing or antifreeze substance necessary to prevent the exhaust water from freezing on the road surface, the metering unit 6 may be controlled by an associate microprocessor based vehicle controller that receives weather information that may include ambient temperature. In one embodiment, the controller receives weather information from an external thermometer 8 and with the aid of this value meters the required quantity of deicing or antifreeze substance based on the measured or estimated amount of exhaust water.

[0027] In addition, in one or more embodiments, a switching valve 9 controls a bypass 11 and the path of the exhaust air via the condenser 5. In the case of current or predicted external temperatures that are not conducive to formation of roadway ice, the exhaust air is subsequently discharged directly into the environment via the bypass 11. In the case of current or predicted ambient and/or roadway conditions conducive to freezing, such as temperatures below 2 C., for example, the controller controls switching valve 9 to route the exhaust via the condenser 5 and the metering unit 6 is activated so as to meter the quantity of deicing or antifreeze substance based on the vehicle and ambient operating conditions, such as the measured or predicted volume of discharge water and the measured or predicted ambient or roadway temperature.

[0028] In one or more embodiments, vehicle 1 may include a water reservoir or accumulator to storage exhaust water for more accurate dosing with the deicing or antifreeze substance. The treated water is subsequently discharged to the environment.

[0029] As such, embodiments according to the disclosure may provide various advantages. For example, a discharge water treatment system according to embodiments of the disclosure treats the water produced during operation of a hydrogen fuel cell to lower the freezing temperature of the water based on current or predicted ambient and/or roadway operating conditions.

[0030] While representative 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.