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NHW20 GPH data?

Discussion in 'Gen 2 Prius Fuel Economy' started by bwilson4web, Oct 7, 2010.

  1. bwilson4web

    bwilson4web BMW i3 and Model 3

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    I was writing up a note about "micro hybrids," the Start/Stop ones, and realized I didn't have the fuel consumption for our old, 1.5L, 2001 Echo. However, I'd sold it to one of my co-workers and we measured:

    • coolant > 180 F
    • "P" (or "N")
    • 700-800 rpm
    • 0.15 GPH
    I'll do the same tonight with our NHW11 but if someone has an NHW20 and can trick the car into "idle" while stopped (aka., ICE running, slip into "N" and car not running.) I'm curious if our Atkinson ICE has an even lower, idle fuel consumption, no load, versus the Echo.

    Thanks,
    Bob Wilson
     
    #1 bwilson4web, Oct 7, 2010
  2. bwilson4web

    bwilson4web BMW i3 and Model 3

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    I was able to measure my NHW11, 2003 Prius idle fuel consumption:

    ~0.17 GPH @900 rpm

    Looking at the ICE rpm, the ratios of fuel consumption and ICE rpm are close enough to be within the margin of error. More accurate measurements are possible but the test Echo had an automatic. The Echo ICE is permanently connected to the hydrodynamic coupler. A more accurate set of data would use a manual transmission Echo in "N". But for my purposes, this is 'good enough.'

    I would not turn down any one with a ScanGauge measuring their NHW20 'idle' fuel consumption and I will do the same with my NHW11 this weekend (I've loaned out my ScanGauge to a co-worker.)

    Thanks,
    Bob Wilson
     
    #2 bwilson4web, Oct 8, 2010
  3. JimboK

    JimboK One owner, low mileage

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    I'll try to remember to check mine later tonight or tomorrow.
     
    #3 JimboK, Oct 8, 2010
  4. JimboK

    JimboK One owner, low mileage

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    Not sure how much good this will do you ... CAN-View and ScanGauge 1 report GPH only to one decimal place. CV reports it at 0.1 GPH and SG at 0.2. The difference could be attributable to rounding error, minor calculation difference, or both. To split the difference at 0.15 seems reasonable to me. ICE RPM is around 975-1012, depending on which device is reporting it. Each device rounds somewhat differently. CV rounds to the nearest 25 RPM and SG ... not sure.
     
    #4 JimboK, Oct 8, 2010
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  5. wintechsw

    wintechsw Junior Member

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    Gen2 2008
    WT(Water Temp) 87 degrees C
    992 rpm
    0.68 LPH(litres per hour)
    SG II v 3.17


    Sorry metric measurements
     
    #5 wintechsw, Oct 9, 2010
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  6. uart

    uart Senior Member

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    I just thought of a procedure that allows this to be measured without a scan-gauge or other instrumentation. One of the ways I notice that the engine remains running in hybrid stage 3a is because the instantaneous "L/100k" is non-zero.

    So say I'm up to temperature but have not yet got into hybrid stage-4 and I back-off and I start coasting at say 40 km/hr then I might see the fuel consumption go to 1.5L/100k, indicating that the engine is still running.

    I've often thought about using this data to calculate the L/hr but never bothered until Bob posted this request. The calculations are easy enough :

    1.5L/100km = 0.015 L/km

    0.015 L/km * 40 km/hr = 0.6 L/hr

    Please note that this isn't actually data. Those figures of 1.5L/100k at 40k/hr are just my approximate recollections of what I typically see in stage 3. I'll make a more accurate observation of this data next time I get the opportunity.
     
    #6 uart, Oct 9, 2010
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  7. 2009Prius

    2009Prius A Wimpy DIYer

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    Does the engine need to be fully warmed up before taking the measurement?
     
    #7 2009Prius, Oct 12, 2010
  8. uart

    uart Senior Member

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    I think it might suck just a little more fuel if it's not fully warm.

    Here's my updated data (previous was just from approx recollection).

    Stage 3a glide speed = 44 km/hr.
    Glide fuel consumption = 1.5 L/100km

    Therefore the fuel rate was : 0.015*44 = 0.66 L/hr (0.175 US Gal/hr).

    This result seems to be in pretty good agreement with those above. :)
     
    #8 uart, Oct 12, 2010
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  9. 2009Prius

    2009Prius A Wimpy DIYer

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    Data from 2009 Prius:
    0.21~0.20 GPH, S3->S4 (during mandatory stop ritual), 10??~99? RPM, standing still, ICE coolant at 166F, OAT 43F

    More to come later if needed. Have fun! :)
     
    #9 2009Prius, Oct 13, 2010
  10. bwilson4web

    bwilson4web BMW i3 and Model 3

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    The 1.5L engine does:
    [​IMG]
    Following the red "N" line, there is an initial ~30 seconds while the catalytic converters come up to operating temperature. Then the injector timing, the sum per second, slowly decrease as the car warms up. The blue "P" line shows the effect of initially charging the traction battery then about 160 seconds, they converge.

    Bob Wilson
     
    #10 bwilson4web, Oct 16, 2010
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