Freeze tolerant fuel cell fuel pressure regulator
A fuel pressure regulator unit is mounted on a manifold. The fuel pressure regulator unit includes a housing providing a fuel inlet passage, a regulated fuel outlet passage, a sense pressure passage, a recycle passage and a mixed fuel passage. A pressure regulator is provided in the housing and is arranged fluidly between the fuel inlet passage and the regulated fuel outlet passage. The sense passage fluidly interconnects the mixed fuel passage and the pressure regulator. The pressure regulator is configured to regulate the flow of fuel from the fuel inlet passage to regulated fuel passage in response to a pressure from the sense pressure passage. An ejector is arranged within the housing and fluidly between the regulated fuel outlet passage and the mixed fuel passage. An ejector is configured to receive recycled fuel from the recycle passage.
1. A fuel pressure regulator unit for a fuel cell comprising:
a housing providing a fuel inlet passage, a regulated fuel outlet passage, a sense pressure passage, a recycle passage, and a mixed fuel passage;
a pressure regulator provided in the housing and arranged fluidly between the fuel inlet passage and the regulated fuel outlet passage, the sense pressure passage fluidly interconnecting the mixed fuel passage and the pressure regulator, and the pressure regulator configured to regulate the flow of fuel from the fuel inlet passage to the regulated fuel passage in response to a pressure from the sense pressure passage;
an ejector arranged within the housing fluidly between the regulated fuel outlet passage and the mixed fuel passage, the ejector configured to receive recycled fuel from the recycle passage; and
a generally vertical recycle line having a first end and a second end opposite the first end, the recycle line having no 90 degree bends between the first end and the second end, the recycle line having a first recycle fitting at the first end and a second recycle fitting at the second end, wherein the first recycle fitting is connected to the housing at the recycle passage at an angle of about 45 degrees, and a passage within the second recycle fitting is connected to a manifold of the fuel cell at an angle of 45 degrees above horizontal, and
wherein the housing includes an installed orientation in which the sense pressure passage is arranged at an oblique angle to vertical and the ejector is arranged vertically.
2. The fuel pressure regulator unit according to claim 1 , comprising a heater engaging the fuel pressure regulator unit.
3. The fuel pressure regulator unit according to claim 2 , wherein the housing includes a heater cavity, and the heater is arranged within the heater cavity.
4. The fuel pressure regulator unit according to claim 2 , wherein the heater is wrapped around the housing.
5. The fuel pressure regulator unit according to claim 2 , comprising a controller in communication with the heater and a temperature sensor, the controller programmed to command the heater in response to a freeze condition to heat the housing.