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Thread: Micra power steering (electric)

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    Member MasterFocus's Avatar
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    Micra power steering (electric)

    Admin note: split this discussion from this thread... http://micra-forum.com/showthread.ph...-from-Qu%E9bec!

    ---


    Quote Originally Posted by MetroMPG View Post
    Power steering delete on the Micra should be super easy: find the electric assist fuse, pull it out.

    I did the same thing on my Honda Insight (sold last summer).
    Wait, its an electric steering?? There is no shaft going to the rack and pinion?



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    Administrator MetroMPG's Avatar
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    Yep, electric assist, not hydraulic.

    But it's not "steer by wire" - it's just a "booster" motor on a conventional steering setup.

    I'm not sure how it's connected mechanically, whether the 12v motor is on the steering shaft or on the rack.

        __________________________________________

        click to view fuel log View my fuel log 2015 Micra S manual: 5.0 L/100 km ... 56.5 mpg (Imp) ... 20.0 km/L ... 47.0 mpg (US) ...


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    Member MasterFocus's Avatar
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    Oh, ok!!
    I guess it create less parasitic drag on the engine

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    Senior Member AlphaMicra's Avatar
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    Quote Originally Posted by MasterFocus View Post
    Oh, ok!!
    I guess it create less parasitic drag on the engine
    The difference in the loss in parasitic drag on the engine caused by the hydraulic pump is now replaced with an increased load demanded by the alternator, so six of one, half dozen of the other in that regard. Electronics are more fault-tolerant than hydraulic systems, and probably save car companies a few cents per unit in mass production.

    In our culture obsessed with absurd excess, the Nissan Micra is my counterculture car of choice.
    Be sure to visit my blog at mymicra.com!

        __________________________________________

        click to view fuel log View my fuel log 2015 Micra SV manual: 6.4 L/100 km ... 44.3 mpg (Imp) ... 15.7 km/L ... 36.9 mpg (US) ...


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    Administrator Daox's Avatar
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    It does provide benefit. Even when the hydraulic PS isn't being used, it is still pumping fluid through a bypass. The electronic steering doesn't have this issue and is much more versatile to developers as they can simply program in what they want versus dealing with valving, springs, etc. This gives you more steering assist at lower speeds where its needed, but much less at higher speeds which also improves road feel and driving experience.

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    Administrator MetroMPG's Avatar
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    Electric vs. hydraulic isn't a wash - there's a small efficiency gain from e-power assist because it avoids the constant belt/pulley/pump losses (regardless of road speed). Whereas the e-motor only draws power when it's called on to provide assist at lower road speeds/steering load.

    More of a case of 4 of one, two thirds of a dozen of the other.

    EDIT: DOH... jinx on daox!

        __________________________________________

        click to view fuel log View my fuel log 2015 Micra S manual: 5.0 L/100 km ... 56.5 mpg (Imp) ... 20.0 km/L ... 47.0 mpg (US) ...


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    Senior Member AlphaMicra's Avatar
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    I'm still a bit skeptical, because the alternator that delivers the power for the EPS is still belt-driven. Whenever a greater load is placed on the alternator, it becomes more difficult for the engine to turn. Then there's the losses inherent in converting electrical energy into kinetic energy, whereas a hydraulic system simply moves kinetic energy from one place to another without converting the energy type. I am reminded of the electronic supercharger debate; however, I realize I'm probably over-estimating the efficiency in the design of a cheap mass-produced power steering pump.

    In our culture obsessed with absurd excess, the Nissan Micra is my counterculture car of choice.
    Be sure to visit my blog at mymicra.com!

        __________________________________________

        click to view fuel log View my fuel log 2015 Micra SV manual: 6.4 L/100 km ... 44.3 mpg (Imp) ... 15.7 km/L ... 36.9 mpg (US) ...


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    Member MasterFocus's Avatar
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    Quote Originally Posted by AlphaMicra View Post
    I'm still a bit skeptical, because the alternator that delivers the power for the EPS is still belt-driven. Whenever a greater load is placed on the alternator, it becomes more difficult for the engine to turn. Then there's the losses inherent in converting electrical energy into kinetic energy, whereas a hydraulic system simply moves kinetic energy from one place to another without converting the energy type. I am reminded of the electronic supercharger debate; however, I realize I'm probably over-estimating the efficiency in the design of a cheap mass-produced power steering pump.
    Dont forget that when not in use (going strait) the EPS put no load at all on the engine, but an hydrolic pump will put a load even when not in use.

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    Administrator MetroMPG's Avatar
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    a couple of numbers

    Ford switched from hydraulic to electric power steering on the Escape & Mariner and saw an 8% fuel economy increase.

    It's one of the top technologies on percent of fuel returned for the dollar that you put in," said Ali Jammoul, Ford's chief engineer for chassis in North America.
    Toyota reported a 3-5% gain depending on model.

    Source: Carmakers Switching to Electric Motors - The Washington Post

    Nissan says about the Versa sedan (same system as the Micra):

    ...electric power steering system ... eliminates the traditional, engine-power draining hydraulic steering pump. This helps to increase fuel efficiency, as well as engine performance.

        __________________________________________

        click to view fuel log View my fuel log 2015 Micra S manual: 5.0 L/100 km ... 56.5 mpg (Imp) ... 20.0 km/L ... 47.0 mpg (US) ...


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    Member MasterFocus's Avatar
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    Quote Originally Posted by MetroMPG View Post
    Ford switched from hydraulic to electric power steering on the Escape & Mariner and saw an 8% fuel economy increase.



    Toyota reported a 3-5% gain depending on model.

    Source: Carmakers Switching to Electric Motors - The Washington Post

    Nissan says about the Versa sedan (same system as the Micra):




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