Pressure sensor system

Pressure sensor system

To ensure safe operation of the complete Clean Energy system, the BMW Hydrogen 7 vehicle requires an optimised permanent pressure monitoring of the pressure in and around the hydrogen tank. This task is performed by the Clean Energy control unit (CESG) by monitoring nine pressure sensors distributed throughout the fuel supply system (KVA).

Sensor monitoring

In the BMW Hydrogen 7 vehicle, pressure sensors are fitted in the following positions:

• two sensors to sense the tank pressure
  
• one sensor on the engine shutdown valve
  
• two sensors on the H2 control lines (liquefied and gaseous)
  
• one sensor to sense the ambient air
  
• one sensor at the boil-off management
  
• one sensor on the pressure accumulator
  
• one sensor on the partial-flow control valve
  

Component diagnosis

These pressure sensors are subject to component monitoring by diagnosis. Within the framework of the test modules for these components, the following faults are covered:

• 6491 tank pressure too high
  
• 64A0 pressure sensor at outlet of partial-flow control valve
  
• 64A2 pressure sensor at outlet of engine shutdown valve
  
• 64BA tank pressure too low
  
• 649F pressure sensor at outlet of partial-flow control valve
  
• 64CA pressure sensor at inlet of PRS pressure accumulator
  
• 64D4 pressure fault in pressure accumulator
  
• 64D5 pressure build-up fault in pressure accumulator
  
• 6493 boil-off operating point
  
• 64A1 pressure sensor at outlet of boil-off valve
  
• 64A1 pressure sensor at inlet of boil-off valve
  
• 64CB boil-off valve
  
• 64B2 air pressure sensor 1
  
• 64C9 pressure sensor in control line for liquefied H2
  
• 64D3 pneumatic system, pressure build-up or reduction
  
• 64EC pressure sensor for ambient air, engine management system
  
• 64C8 pressure sensor in control line for gaseous H2
  
• 64A3 pressure sensor at inlet of boil-off valve