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*GOLD STAR* Kudos To Engineer/Engineering Team Who Designed Prius v ("vee") HSI

Discussion in 'Prius v Fuel Economy' started by catgic, Jan 7, 2012.

  1. catgic

    catgic Mastr & Commandr Hybrid Guru

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    Gathered “Vee” Fuel Misers - My 2¢…I am still on up slope of the knee of the Learning Curve with my new Prius v ("vee"). However, I had occasion yesterday to drive in near-zero traffic density on a straight, mostly flat and level stretch on Florida State Road A1A (SR A1A), which runs oceanside along the Atlantic Ocean here on the Space Coast. I took the opportunity to “play” (i.e. experiment & observe) with the Prius v’s throttle settings versus Hybrid System Indicator (HSI) display versus instantaneous miles per gallon (impg) displayed in the Multi-Information Display (MID), and even caught the Super "Atkinson" Highway Mode a time or two as I tooled along by myself at bracket speeds of 45-55 MPH using the OEM HSI/MID in the “vee.”

    What I found was the lines on the Prius v HSI track very well with the indicated impg for a particular level of throttle setting-depression, and when the ECO Leaf light illuminates on or off along the “Green Lines Range” range portion of the HSI gauge-display.

    I tinkered at the granularity level of a single Green Line for a given impg amount displayed, mentally noting for my future Hybrid $mart driving use what each line (i.e. notch) produced or withdrew in impg along with ECO Leaf and EV Car display illuminations, or lack there of. Bottom-line…the HSI in my “Caddy In A Kimono” is very useful to this “Purist” Pseudo-Hypermiler/EcoDriver who only “purely” uses OEM, “Stock” instrumentation “flying” my fuel-sipping sorties.

    FWIW FYI: At 277-miles into this current tank of fuel, with me running on Up-Pressured Toyo Proxes A20 P215/50R17-90W tires, the MPG average displayed is 53.2 MPG.

    This Hybrid Zen Master is luvin’ those Kaizen Kids from Toyota Town.

    [​IMG]
     
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  2. SageBrush

    SageBrush Senior Member

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    The correspondence you saw breaks down when the traction battery SOC changes. This is an HSD hybrid with power splitting, after all.
     
  3. catgic

    catgic Mastr & Commandr Hybrid Guru

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    SageBrush – The correspondence I saw “corresponded†to what I observed. I made no mention in my post, one way or the other, about the state of the State Of Charge (SOC). The power-splitting ratio was in a condition of “ratio’ed balance†during each segment of my different observations.

    All a moderate plus or minus, “notch up or notch down,†change in the SOC would do would be to increase or decrease the power-split ratio, ratcheting the displayed impg, up or down a bit. However, the Green Lines on the HSI would remain useful for showing the driver-operator the relative level of “Hybrid $martness†with which he or she is driving for a particular level of throttle setting-depression and Traction Battery charge.

    I cannot speak for yours or other Prius v (“veeâ€) drivers ability to connect to, and “Become At One With The Vee’s HSD,†and log “$tellar†MPG numbers --- only mine. The self-reports for the MPG-FE say they are seeing 31.9, 33.0, 35.5, 36.0 36.4, 37.3, 37.6, 39.0, 39.2, 39.4, 39.9, 40.1, 41.8, 42.0, 43.6, 43.9, 44.3, 44.4, 44.6, 44.9, 45.0, 45.3, 45.7, 46.0, 46.5, 47.2, 47.7, 47.8, 48.4 on their new, 2012 Prius v (“veeâ€)s. I am running an average MPG, which is 67% above the very lowest reported MPG and 10% above the very highest MPG reported.

    I find the Vee’s OEM HSI/MID/MFD instrumentation combination to be an extremely useful aid to this Prius Borg in attaining and maintaining the 125%± of EPA MPG Fuel Economy numbers I continue to consistently log. Again, Watakushi gives a *GOLD STAR* to the design engineering folks at Toyota Werks for the HSI/MID/MFD solution implemented in the “stealthy†Magnetic Gray Metallic w/Gray SofTex & Max-Legal Window Tint 2012 Prius v―Level Five ATP Petrol Warfighter I am piloting. :plane:
     
  4. cycledrum

    cycledrum PSOCSOASP

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    Oh my you sure enjoy the details. Sounds like the car is working very well for you, and I concur, the HSI gage in mine is helpful in getting higher MPGs.
     
  5. SageBrush

    SageBrush Senior Member

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    catgic, I think you are missing the forest for the trees.

    The HSI meter shows total power output, not isolated ICE output. My CTh has the same meter, but it can alternate to show an RPM meter too. The latter is a better indicator of ICE power, although you do have to make mental guesses as to torque. My rule of thumb is too not worry about RPM speed going uphill, and to get into the 2000-2500 RPM range going downhill.

    The comments are directed at drivers interested in best ICE efficiency, which is where the game is at.
     
  6. catgic

    catgic Mastr & Commandr Hybrid Guru

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    SageBrush – You are nice person-U-ME’ing too much in the way of forestry. I am not missing anything, and I know where the bears go in buckwheat, as well.

    The Prius v HSI does not display RPM. My Prius HSD honed foot does a fine fuel-sipping job of DWL going uphills, and I use iMPG = ½iMPH to guesstimate optimal ICE RPM/Power when accelerating.

    As I have said in previous posts, I am an OEM Instrumentation Purist. As a result, I shall not be bolting on a Tachometer to my beauteous Prius “vee.â€