Steady State Speed vs Fuel Economy results

Discussion in 'General' started by seftonm, Mar 22, 2014.

  1. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi All:

    Temps from 46 to 48 degrees F with winds calm on the multiple NB and SB runs. From the calibration drive, the aFCD offset "may" be 0.982 * indicated aFCD. SoC could not be deduced since there is no SoC display. As mentioned previously, the std. display does how kW consume from the ICE and the pack. During acceleration up to 65 and 70 mph, the ~ .5 miles to the reset launch point in both directions showed SoC. If I had a longer run up, I could have removed that SoC use but the exits on this stretch of I5 across Camp Pendleton would have incurred another 25-mile loop just to turn around, accelerate to speed, and reset at the exact elevation points on my test segment(s).

    2020 Ford Escape Hybrid AWD Titanium

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    Displays reset and "possibly" topped off.

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    46.3 mpg over 201.5 miles indicated, 205.6 miles on 4.518 gal = 45.5 mpg actual, 0.982* aFCD = Actual mpg.

    [​IMG]
    Just minutes before the Steady States data collection.

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    With the Capless refueling not allowing a more accurate aFCD offset and this SoC use while accelerating to 65 and 70 mph before the actual measured runs, there are a number of inaccuracies that could have worked into the chart above.

    Using straight line analysis, the EPA highway (37 mpgUS) crossover occurred at 63.5 mph. I suspect the large 19s took the 2020 Ford Escape Hybrid to the woodshed vs the 17's on the Escape SE Sport Hybrid for example. The EPA highway for the Titanium trim (67.5 mph) occurs at 34.3 mph or a 34-mpg highway rating is what it should actually be rated at. Again, this result could be significantly higher - 1 to 2 mpg higher - as I know there was pack use during the 65 and 70 mph accelerations prior to the reset for the measured segment.

    Wayne
     
    EdwinTheMagnificent and BillLin like this.
  2. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi All:

    From the 2019 Kia Niro EV Review, our first steady states data collection with an all-electric!

    2019 Kia Niro EV Calibration Drive

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    Reset to 6.1 miles/kWh over 12.1 miles indicated, 12.7 miles actual.

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    Reset to 2.061 kWh with the Niro EV's battery from 98% to Full SoC.​

    12.7 miles on 2.061 kWh = 6.16 miles/kWh indicate a positive 0.9 percent aECD offset.

    2019 Kia NIro EV

    [​IMG]
    Just moments before the Steady States last night.​

    Temps from 49 to 51 degrees and calm winds for the NB and SB runs and 50, 55, 60, 65, and 70 mph indicated is actual per the Garmin. The 2019 Kia Niro EV Speed vs Energy Efficiency curve looks like this...

    [​IMG]

    The EPA highway rating of 3.03 miles/kWh was deduced from the Niro EVs 102 MPGe highway/33.7 kWh/gal.

    The EPA Highway efficiency crossover on a straight line estimate occurred at 73.0 mph indicating the 2019 Kia Niro EV is a bit more efficient than its 3.03 miles/kWh would indicate. I have found it is more efficient than its 3.65 miles/kWh rating around town as well.

    Wayne
     
    kbergene, BillLin and Carcus like this.
  3. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi All:

    From the 2020 Toyota Prius AWD-e intro, first drive, and now review week (url=2019 Toyota Prius Gains Traction Just Weeks from Today), the steady state details follow.

    2020 Toyota AWD-e Calibration Drive

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    Initial topoff at a Shell in Torrance, CA with the aFCD, Trip A, and Garmin reset.

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    Final topoff at a Shell in Carlsbad, CA.

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    81.6 mpg over 79.6 miles indicated, 81.4 miles on .988 gallons = 82.4 mpg actual.​

    A suspect positive aFCD offset of 1.0098 or 1.01 was the result. I was actually surprised to see an aFCD positive offset on a Prius as our experience has shown only the topoff to topoff refuels in prototypes have provided a positive or neutral offset. When we get our hands on the consumer model(s), the offsets go negative up to a maximum of 9 percent as we experienced from an Eco trim during a triple digit result while driving from the IL/WI border to Detroit a few years back.

    While I have some confidence in the measured result, I went on to consume an entire tank and refuel just to make sure this was not an anomaly... 4-days later, I am sure glad I ran this tank down to come up with a more accurate aFCD offset and it is negative as expected.

    2020 Toyota Prius AWD-e Final aFCD Calibration

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    66.5 mpg and 544.1 miles indicated - 556.4 miles actual on 8.932 gallons = 62.3 mpg.​

    The aFCD offset is .937 or negative 6.3 percent.

    2020 Toyota Prius AWD-e

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    [​IMG]

    Just moments prior to Steady State data collection last night and into this morning.​

    And the 2020 Toyota Prius AWD-e's Speed vs FE graph.

    Temps ranged from 52 to 55 degrees and winds were calm during the data collection. Indicated speed from the speedometer was 1 mph low of actual from 50 to 70 mph. Data was collected at 51, 56, 61, 676, and 71 mph indicated and 50, 55, 60, 65, and 70 mph actual.

    SoC changes were non-existent other than 1 bar loss at 70 mph on the NB run. It recovered within 100 yards of passing the flying data record point so there was a minimal effect.

    [​IMG]

    On a straight-line analysis, the EPA highway (48 mpg) crossover occurred at just 66.7 mph. While the 66.7 mph EPA highway crossover indicates the EPA highway estimate is fine but this result is the lowest crossover speed we have seen from any Toyota or Lexus to date. It was close and I suspect those optional 10-spoke chromed alloys our Prius AWD-e was equipped with were a factor in this somewhat low result.

    Wayne
     
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