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Max Torque vs MPH

Discussion in 'Gen 3 Prius Technical Discussion' started by sipnfuel, Mar 1, 2011.

  1. sipnfuel

    sipnfuel New Member

    Joined:
    Jan 21, 2011
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    Location:
    So. Cal.
    Vehicle:
    2010 Prius
    Model:
    II
    I decided to make a Torque vs MPH chart to show the max available torque at any given MPH.

    Please note this is the output of the PSD at the ring gear. To compare another vehicle's torque, please consider its torque after the transmission, not at its engine.

    Also note this is before the final reduction at the differential.

    I did double-check my results using conservation of energy. If I made a mistake, please point it out.

    Some things you see in this chart, for example
    @ 2 MPH, the ICE can only spin at 2844 RPM, limited by MG1 @ 10,000 RPM. At this RPM, the ICE can only produce about 75 lb-ft of torque. Only ~72% gets directly outputted to the wheels, so you see a value of approximately 54 lb-ft from the ICE at 2 MPH. The rest of the ICE's torque is used by MG1 to generate electricity to send to MG2. MG2 can produce 153 ft-lb of torque @ 2 MPH, which is geared up by 2.636 to 403 ft-lb to the ring gear.

    Some things you can sorta see in this chart:
    It's only at around 45-46 mph that the ICE can spin at 4200 RPM to produce full torque. Finally around 60 mph, increased ICE power is more significant than the maximum ICE torque. ICE RPMs are ramped up so that by 86 mph the ICE is up to 5200 RPM to achieve its maximum 98 horsepower.
     

    Attached Files:

    tpenny67 and briank101 like this.
  2. jworms

    jworms atypical owner

    Joined:
    Feb 23, 2011
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    Vehicle:
    2012 Prius
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    IV
    are there dyno charts available for these cars? a dyno would probably be able to provide similar results for torque measured at the wheels.