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Featured Buick eAssist

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by bwilson4web, Jun 6, 2017.

  1. bwilson4web

    bwilson4web BMW i3 and Model 3

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    After five years with Chevette, a rented GEO Metro, watching the EV1 fiasco, and Saturn, I am not a fanboy of GM but they have occasionally done good:

    Light Electrification Leads 2018 Buick LaCrosse Updates

    DETROIT — The Buick LaCrosse expands its technological credentials by adding eAssist light electrification for the 2018 model. The combination of an electric motor with Buick’s latest 2.5L four-cylinder engine delivers quiet, refined and spirited efficient performance backed by the value and customer experience expected of Buick.

    This new eAssist system, when coupled with the four-cylinder engine, has a 19 percent increase in city fuel economy compared to the LaCrosse’s advanced V-6 and leverages a compact lithium-ion battery pack to provide select benefits found in fully electric vehicles, such as torque-assisted launch, energy-saving regenerative braking and exceptionally smooth stop/start. It will be the standard powertrain for the 2018 LaCrosse, which goes on sale this fall.
    . . .

    The press release is light on technical details so: Green Car Congress: Buick adding new eAssist mild hybrid to 2018 Buick LaCrosse as standard powertrain

    Buick’s eAssist propulsion system combines a compact electric motor and an advanced 24-cell air-cooled 0.45kWh lithium-ion battery pack with the 2.5L four-cylinder gas engine to enhance efficiency and maintain refined performance through:

    Motor Generator Unit (MGU): Replaces the traditional alternator and acts as an electric motor to assist the engine when needed. It also acts as an electric generator providing the energy stored in the lithium-ion battery pack.

    Electric Assist: The MGU’s electric motor function provides a power boost for an extremely smooth launch from the Auto-Stop mode. It funnels additional torque to the engine when needed to optimize overall driving performance and efficiency.

    Regenerative Braking: When braking or coasting, some of the energy normally lost is converted to electricity through the MGU and stored in the lithium-ion battery pack.

    Lithium-Ion Battery Pack: The 86V lithium-ion battery pack, which has been repackaged to be more compact, stores energy captured during regenerative braking. This energy powers the electrical system when the vehicle is in Auto-Stop mode. It also powers the MGU to provide a smooth launch from Auto-Stop mode or additional torque to the engine as needed.

    Seamless Stop/Start Technology: Contributes to added fuel savings by seamlessly turning off the engine when in Auto-Stop mode (e.g., at a stoplight or in heavy traffic) and restarting when the foot lifts off the brake pedal or presses the accelerator.

    Aero Improvement: Upper and lower active aero shutters in the front fascia close under certain driving conditions to help maximize aerodynamics and contribute to improved fuel economy
    IMHO, the electric motor should be connected or part of the transmission. Belt-assisted (BAS) systems means the engine overhead will limit the motor assistance and make electric-only driving impractical. Notice they are using "86V", not "48V" advocated by Continental and only claiming "19%" improvement versus the inflated claims by Continental.

    Bob Wilson
     
    #1 bwilson4web, Jun 6, 2017
    Last edited: Jun 6, 2017
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  2. bhtooefr

    bhtooefr Senior Member

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    Although, the voltage just means that they can use thinner wires for the same power, really, that's all.

    The reason why the suppliers are clustering around 48 volt systems is because 48 volts is low enough that no special personal protective equipment is required to work on a 48 volt system, whereas on anything higher than 50 volts, it is. However, now that a lot of shops have that PPE thanks to hybrids being common enough, that's less of a concern.

    A BAS can still help, even if it's not ideal - while it's utterly unable to shut off the engine under power due to operating through the engine (although Audi's system can shut it off under coasting up to 99 mph, allegedly), if battery charge is managed appropriately, it is able to load down the engine to avoid inefficient light load operation (and save the resulting excess energy for later), and it is able to assist the engine to avoid inefficient high RPM operation (using that saved energy).
     
    #2 bhtooefr, Jun 6, 2017
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  3. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Perhaps time to define this term?
    Old school, I try to expand an acronym on first reference. But I'm an old, old man and you kids get off my yard!
    So I went to Greencarcongress to find the latest: Green Car Congress: Audi unveils Q8 sport concept with 48V mild hybrid system (mHEV); drive system coming to “many” Audi models

    Audi unveils Q8 sport concept with 48V mild hybrid system (mHEV); drive system coming to “many” Audi models
    7 March 2017
    At the 2017 Geneva International Motor Show, Audi is presenting the Audi Q8 sport concept, a new performance-oriented take on the Q8 concept study introduced at the 2017 Detroit Motor Show. Equipped with a 3.0 TFSI six-cylinder engine featuring a 48V mild hybrid system (mHEV) and an electric compressor, the SUV

    I wish they weren't 'concept' but production cars. But searching further, I found: Green Car Congress: Continental puts first 48V hybrid assist system into production with Renault diesels

    [​IMG]
    This makes more sense.

    Read the comments too because one interesting variation is a +48V, And, -48V system. This allows using 96V for power bringing 'sustain velocity' into a reasonable speed range. A 'less bad' solution, it makes more sense.

    Bob Wilson
     
    #3 bwilson4web, Jun 6, 2017
    Last edited: Jun 6, 2017
  4. bhtooefr

    bhtooefr Senior Member

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    Edited to expand the acronym, and I just posted a thread about Audi's introducing cars with it this year, FWIW.
     
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  5. mmmodem

    mmmodem Senior Taste Tester

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    Seems rather complicated for 19% better fuel economy. The 2009 Rav4 V6 to I4 was a 16% increase in City fuel economy. (19 to 22) and the 4 had a 4 speed auto versus 5 gears in the 6.
     
  6. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Ordinarily I would agree but unlike earlier efforts, Buick downsized the engine to 2.5L and offers the eAssist for a lower price (if the articles are accurate.) This reduces the 'sting' whereas the earlier Belt Assisted (BAS) systems were more expensive.

    Bob Wilson
     
  7. bhtooefr

    bhtooefr Senior Member

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    The previous-generation LaCrosse also had a choice between a 2.4 liter eAssist powertrain and a 3.6 V6 powertrain.

    The eAssist system was used to facilitate the engine downsizing, by filling in the lack of low-end torque from the 2.4 liter, when moving such a large vehicle. However, you did lose trunk space as a result.

    That said, the eAssist powertrain also saw use in the Regal, where you could get the 2.4 liter without a hybrid system. A 2014 2.4 got an EPA rating of 19 city/30 highway, whereas the 2.4 eAssist got a rating of 24 city/35 highway - so it definitely helped, even if it didn't get it into the realm of full hybrids. (My guess is that the added low-end torque from the eAssist system allowed for taller gearing and better highway mileage.)
     
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  8. bwilson4web

    bwilson4web BMW i3 and Model 3

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    If offered for less, a negative hybrid premium, that would be good news because it would encourage exactly the type of market shift needed. We'll have to wait until it shows up on the market place.

    Bob Wilson
     
  9. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    BAS systems are a great way to be able to slap HYBRID in 12 inch tall letters on a car that gets the same MPG as every other model.
     
  10. bwilson4web

    bwilson4web BMW i3 and Model 3

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    That was true when Bob KLutz was in charge.

    Bob Wilson
     
  11. bhtooefr

    bhtooefr Senior Member

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    To be fair, Lutz also ended up getting behind the Volt.

    And, the ones that had twelve inch HYBRID lettering were actually quite a bit more efficient than their non-hybrid counterparts (and they weren't BAS, either, they were power split boxes). It's just that the premium for that system was quite high, and MPG is a way of reporting efficiency that minimizes large improvements in inefficient vehicles, and magnifies small improvements in already efficient vehicles. I mean, 5 gallons per 100 miles is far better than 6.7.
     
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  12. Trollbait

    Trollbait It's a D&D thing

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    This is the same eAssist system that is being offered in California Silverados. The motor and battery is actually less powerful than the eAssist that was previously in the LaCross/Malibu, though I don't know if the older one used ultracaps. The Malibu had dropped the eAssist when a newer engine with start/stop alone got the same EPA numbers on the window sticker. So the current system being less powerful may not be a negative when used with a better, newer engine.

    That first eAssist was also offered on the Impala. I only learned about it after spotting an entry for it in one of the Dashboard reports.