Electric motor vs Gas engine performance

This topic contains 6 replies, has 2 voices, and was last updated by  Mellissa Kelley 3 months, 3 weeks ago.

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  • #10021

    Mellissa Kelley
    Participant

    I Saw the other topic on electric motor vs engine, and wondered what the performance differences are?


  • #10022
    John C
    John C
    Galco Representative

    Hello Mellissa, and thanks for asking Galco.
    These topics are not our area of expertise. However we do know electric motors very well here. I personally have worked in automotive R&D before my career in Industrial and understand a few things about cars and the modern Combustion engine.
    Probably the single biggest difference between an Electric motor and a Gas powered Engine is the Torque curves. Electric motors have what some engineers have been trying to do with the combustion engine for decades, develop a flat torque curve.
    Electric motors can produce output shaft torque in the 150% to 200% range from zero to rated RPM. The Gasoline combustion engine is effectively an air pump with a specific volumetric efficiency speed. The faster it spins the more air it moves. So the faster a Gas engine spins the more torque it can produce up to a certain speed where the torque will start to fall back off again. At zero speed a gas engine produces zero torque, and at maximum speed the torque has already started falling off again. So max torque is somewhere between zero and max RPM, ok?


  • #10023

    Mellissa Kelley
    Participant

    Ok so how does the electric motor produce such a flat torque curve?


  • #10024
    John C
    John C
    Galco Representative

    Well for 1 thing the electric motor doesn’t rely on motion to produce its power like the gas engine does. The Gas engine has to spin some minimum RPM (Idle speed) to run at all. The Electric motor has to have an external supply source of regulated power to run. The external power source can allow maximum current and if is an AC motor it can be connected to Edison power and may pull up to 600% of rated current for a few seconds/minutes, depending on the size and load. It won’t necessarily produce 600% rated torque though but will be very high until it gets up to speed.


  • #10025

    Mellissa Kelley
    Participant

    If an electric motor uses up to 600% why did you say 150% to 200%?


  • #10026
    John C
    John C
    Galco Representative

    That is a fair question, so let me explain.
    In a hybrid vehicle the electric motor will have a controller between it and the Battery (the power source). This controller will have the ability to limit the power to that motor based on its programming or the vehicle’s control systems programming, however a particular vehicle happens to be configured. But it could supply full power to the electric motor at any time based on driver input and what they are trying to do with the vehicle, accelerate up to speed, merge with traffic etc. Make sense?


  • #10027

    Mellissa Kelley
    Participant

    Godd enough thank you John


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