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Did hydrogren ICE cars not stall easily?

  1. Jan 7, 2014 #1
    First,this is what I understood from theory:
    If I understood the concept of 'engine stall' correctly,it occurs as a result of the engine not having enough time to adjust for a increased load.

    As a practical example of engine stall,I consider the instance of 'letting go of the clutch pedal' too quickly. When I shift into first gear and let go of the clutch pedal all of a sudden,the engine stalls. I am guessing this is because the engine is 'suddenly' subject to a heavier load and its rpm dropped so low that it couldn't supply enough air to combust the fuel.

    This brings me to the question of the hydrogen Otto engine cars. One of the main properties of hyderogen(this paper says so http://www1.eere.energy.gov/hydrogenandfuelcells/tech_validation/pdfs/fcm03r0.pdf) is its 'HIGH RANGE OF FLAMMABILITY'. This means that a hydrogen Otto engine car could run at lower rpms than a gasoline engine.So,I infer that hydrogen Otto engine cars didn't stall(back in the 60's) when you let-go of the clutch all of a sudden.

    Is my inference valid? Does anyone here have experience with hydrogen-powered cars?
  2. jcsd
  3. Jan 7, 2014 #2


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    Any engine will stall when the torque become insufficient.
  4. Jan 7, 2014 #3


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    The stall is not caused by the fuel being unable to combust, it is caused when the load on the engine is larger than the torque the engine is providing, causing the engine to slow down until it stops. The way to fix this is to increase the throttle when increasing the load, such that the available torque increases as the load does. This would be just as necessary in a hydrogen car as in a gasoline powered one.
  5. Jan 9, 2014 #4
    Understood.But,the full load torque curve of an IC engine is so much higher than the road resistance curve(i.e the curve calculated from the air,friction,incline resistance forces).

    So from my understanding,at idle:the torque curve is the zero-load curve and when I suddenly let-go of the clutch,the road resistance curve with 1st gear would have exceeded the zero-load torque curve(hence causing the stall)?Is this reasoning valid?
  6. Jan 9, 2014 #5
    Yes, the full-load torque curve is normally higher than the road-resistance, however, that full-load torque curve is generated at full throttle. You don't normally dyno an engine at idle - the engine stalls. If the engine torque combined with gearing cannot overcome the initial resistance then the engine will stall. You either need more torque, more gearing or more throttle (which generates more torque) to overcome resistance to motion.
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