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Talk about torque.

Discussion in 'Gen 5 Prius Technical Discussion' started by Maturedriver, Apr 18, 2024.

  1. Maturedriver

    Maturedriver New Member

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    I’m confused. Apparently in the 2023/24 Toyota Prius the 2litre internal combustion engine develops 196hp and 139 ft-lbs of torque. Why in the Prime version does it only develop 160hp with the same engine?

    I know it develops a healthy 220hp when combined with the (surprisingly high) 161hp electric motor but does anyone know how much torque the electric motor produces? Additionally how much torque is produced when the engine and motor work together? Strangely Toyota seems to treat this information as a trade secret.
     
  2. soft_r

    soft_r Junior Member

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    Because it's unimportant info. And if the numbers aren't amazing then there's no benefit to sharing it.

    You get 0-60 in 7s. That information is all that will be relevant to 99.99% of people in their daily driving.

    If you want to know, go get the car dyno'd.
     
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  3. Hammersmith

    Hammersmith Senior Member

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    The internal combustion engines in the Prius and Prius Prime output the exact same hp and torque. The difference in total hp is due to the Prime being able to pull more power from the larger battery. Also, the total net power output is not the sum of the different power sources.

    Prius/Prime M20A-FXS
    150hp @6000rpm
    139lb-ft @4400-5200rpm

    Prius HEV Electric Motor
    111hp
    83kW

    Prius HEV AWD Rear Electric Motor
    40hp
    30kW

    Prius Prime Electric Motor
    161hp
    120kW

    Net Power Output
    Prius Prime - 220hp
    Prius HEV AWD - 196hp
    Prius HEV FWD - 194hp
     
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  4. Maturedriver

    Maturedriver New Member

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    Thanks for that but still no mention of electric motor torque and total torque figure.
     
    #4 Maturedriver, Apr 18, 2024
    Last edited: Apr 18, 2024
  5. Maturedriver

    Maturedriver New Member

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    Strange and unhelpful response.
     
  6. ChapmanF

    ChapmanF Senior Member

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    ... which is ('cause somebody's bound to ask) because some of the power from the engine is delivered to the output mechanically, while the rest goes through the electric motor. Therefore, the power rating of the electric motor has to include that portion of engine power; it is not entirely a separate source of output power.
     
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  7. Trollbait

    Trollbait It's a D&D thing

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    From Toyota's site, the engine in both produces 150hp and 139ft-lbs. The system power of the hybrid is 194hp, though I see the Wiki lists a 193-196 range for that.

    The peak motor was once published for hybrids, but an electric motor's peak is at zero rpms. That isn't of much use to drivers. With the differing torque curves, and a portion of engine torque always going, coming up with a nonconfusing figure is probably a nightmare. Toyota explains the system power in a paper.
     
  8. ChapmanF

    ChapmanF Senior Member

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    I'm pretty sure I remember seeing a torque 'curve' for an MG2 in whatever gen, and it was pretty simple: it was flat horizontal at the spec'd maximum torque from zero RPM right out to where the torque times the RPM equaled the max power. From that point, with increasing RPM, the torque followed the downward curve (max power / RPM), kind of as you'd expect.
     
  9. Maturedriver

    Maturedriver New Member

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    I currently have a 2020 VW Golf Mk8 GTE (PHEV)
    The electric motor develops 114bhp. Torque 243 lbs-ft.
    The engine produces 148bhp. Torque 185 lbs-ft.
    Total of both when working together 247bhp. Torque 295 lbs-ft
    Why can I only find some of Prius Prime’s power and torque figures?
     
  10. Trollbait

    Trollbait It's a D&D thing

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    I don't recall Toyota ever posting a net torque for a hybrid. They used to for the motors, but now you have to go elsewhere to find even the power rating of M/G1 or whatever they now call it. Some of it is likely because the buyers Toyota mostly attracts buyers that likely don't care, and the company doesn't want to risk data overload scaring them. The general public is still clueless about hybrids. Some even about cars in general. The fact that our salespeople tend to know little about any of the cars they sell could also play into it.

    As for the Golf, VW is using a very different hybrid system. It is parallel hybrid with a traditional transmission. There is one powerful motor that simply inputs input into the drive train using energy banked in the battery. The same motor charges the battery, either through regen braking or driven by the engine. The math here is simple.

    The Prius and most Toyotas use a power/split system. These work as a parallel and series hybrid at the same time. There are two powerful motors. M/G2 is on the tail end of the drive train, and is the traction motor. M/G1 is buried in the eCVT. The planetary gear stet in the eCVT always diverts @20% of the torque generated by the engine to M/G1. Which then uses the electricity to drive M/G2 or charge the battery.

    So the torque reaching the wheels from the engine is not the full torque the engine produced. The math is starting to complicate. Then M/G1 may not take all the torque it receives from the engine to make electricity. The system can vary its output, thereby simulating the variable gear ratios for the eCVT.

    For both types of hybrid systems, the manufacturers have to also consider the battery. Max motor output only comes from banked energy in the battery, and it won't last long. In the early hybrid days, the gen1 Prius had a turtle warning light to alert the driver that power is limited by a depleted battery.
     
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  11. Maturedriver

    Maturedriver New Member

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    Many thanks for the explanation. Wow! I thought the VW system was complicated (because it uses a twin clutch gearbox) but since the Prius Prime has TWO electric motors I think Toyota wins the prize. When my dealer has a demonstrator I will be able to tell how much torque it has. Have to say on my Golf GTE when the traffic lights turn green if I just tickle the accelerator it’s off like a scalded cat! I hope to replicate this with the Prius PHEV.
     
  12. ChapmanF

    ChapmanF Senior Member

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    Toyota wins both the simplicity and the complication prize.

    Simplicity because the transmission is so utterly minimal and bulletproof. Two motors, a set of gears that are always meshed the same way, nothing that ever clutches or shifts. Simplicity itself.

    Complication because the first time you try to think through what it's doing, there's a bit of mind-bending involved. Once you get through it, that part's simple too.