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Re: THE POWER OF STEALTH!!!!

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  • msdickerson
    Also - keep in mind that we as drivers of the Prius actually have very little control over Stealth mode . About all we can do is be light on the peddle and
    Message 1 of 10 , May 1 9:49 AM
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      Also - keep in mind that we as drivers of the Prius actually have
      very little control over "Stealth mode". About all we can do is be
      light on the peddle and accelerate quickly to get to the light loads
      required to be in Stealth mode.

      steve d.

      --- In toyota-prius@y..., "scouterpmphx" <pmenconi@c...> wrote:
      > Since "stealth" energy comes from the gas engine, I'm not convinced
      > it is an ideal mode. What is ideal, in your description, was a
      > pretty optimal use mode: moderate and steady speeds. That will
      > always greatly improve gas mileage.
      >
      > Pete M
      >
      > --- In toyota-prius@y..., Ameradian1@a... wrote:
      > > So many people have discussed the value of stealth mode on
      > previous posts
      > > that I decided to test the effects of emphasizing stealth mode on
      > mileage.
      > > Where I live, we have innumerable hills so finding a long stretch
      > of flat
      > > road is not easy. I decided however, to take roads that I knew
      > were less
      > > "hilly," and which also had a lower speed limit, which would
      > enhance my
      > > ability to enter into stealth mode. I noticed that on relatively
      > flat
      > > terrain, as long as I stayed at or under 40 mph, I would almost
      > always enter
      > > into stealth mode. Regrettably, this meant that I might
      > inconvenience some
      > > people because I was driving just a bit too slow, but in the
      > interest of
      > > experimentation I decided to give it a go. Anyway, the roads
      that
      > I took
      > > were almost free of stop signs or stoplights for long periods.
      > Normally on
      > > these roads, while going at my normal pace, I can get five minute
      > intervals
      > > of 55 mpg according to the bar on the consumption screen. This
      > time though I
      > > had an astonishing number of high readings. My first high
      reading
      > was at 85
      > > mpg, and then as I entered into town, which has a very slow speed
      > limit of 30
      > > mph, I received readings of 100 mpg--the highest that the
      > consumption screen
      > > will allow for!!! I then got one of 95 mpg and yet another 85
      mpg
      > on the
      > > five minute interval display!! Now let me tell you about the
      > effect it has
      > > had, at least apparently, on "real" fuel economy.
      > > Now, there has been some discussion on this list about the
      > variability
      > > of the Prius fuel gauge readings, due to the bladder tank, in
      > registering
      > > accurate fuel consumption. My car is fairly accurate, however.
      > For example,
      > > I have averaged 44.87 mpg so far and that is done by calculating
      > fuel fill
      > > ups in gallons vs. mileage driven. Not surprisingly, the first
      bar
      > typically
      > > disappears between 40 and 48 mpg, with the largest cluster coming
      > in at 44
      > > mpg. What however has been the effect of utilizing stealth
      mode?
      > Well, I
      > > really can't say yet, because I still have not had my first bar
      > disappear and
      > > I am at 83 miles so far (I push the rest button at every fill up,
      > and then
      > > calculate miles driven vs. fuel entered at the next fill
      > up)!!!!!!!!!!!! All
      > > of this has led me to believe that if I prudently route my
      > destination so
      > > that I can maximize the number of flat roads and lower mph I can
      > enhance the
      > > ability to enter into stealth mode, thus enhancing my fuel
      economy
      > > considerably. However, I need to ask the mavens of battery
      > technology what
      > > this sort of reliance, or should I say over reliance, would have
      on
      > battery
      > > life? Certainly, it is heady wine to be getting somewhere over
      83
      > mpg by
      > > constantly driving off the batteries. I would love to continue
      > this sort of
      > > driving style for I could easily raise my mpg average up past
      50.
      > What
      > > however are the effects on the batteries? Any ideas from
      anyone?
      > Would this
      > > style of driving cause premature battery failure? In any
      > event, "stealth"
      > > driving is awesome, so long as the driver does not mind going a
      bit
      > slower.
      > > Cheers
      > > Bill
    • john1701a
      ... Fortunately, not all of it though. Some of us like to play with hills to generate electricity. Planning an efficient climb up then a full glide down
      Message 2 of 10 , May 1 10:02 AM
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        > Since "stealth" energy comes from the gas engine

        Fortunately, not all of it though.

        Some of us like to play with hills to generate electricity. Planning
        an efficient climb up then a full glide down really does produce
        energy benefits, especially on residental streets. That has become
        very routine on my drive home and to work after exiting the highway.
        The MPG goes up, then stays up later when I restart the engine to
        leave.

        Statistically, I really do have examples where stealth pays off. We
        may be able to cross-check that data with the Civic-Hybrid CVT later,
        since it doesn't offer stealth yet it roughly resembles the size &
        weight characteristics of Prius.

        JOHN
        http://john1701a.com
      • hawkmon77
        I posted once about this sort of thing, but didn t put it into mpg terms. The jist was that if I do it correctly I can drive to and from school (about 7 miles
        Message 3 of 10 , May 1 11:11 AM
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          I posted once about this sort of thing, but didn't put it into mpg
          terms. The jist was that if I do it correctly I can drive to and
          from school (about 7 miles each way) in almost all electric mode.
          However, the next time I drive the car, I can barely get it into
          electric mode at all. That third trip spends a good amount of time
          recharging the battery.

          -Joe

          --- In toyota-prius@y..., "scouterpmphx" <pmenconi@c...> wrote:
          > Since "stealth" energy comes from the gas engine, I'm not
          convinced
          > it is an ideal mode. What is ideal, in your description, was a
          > pretty optimal use mode: moderate and steady speeds. That will
          > always greatly improve gas mileage.
          >
          > Pete M
          >
          > --- In toyota-prius@y..., Ameradian1@a... wrote:
          > > So many people have discussed the value of stealth mode on
          > previous posts
          > > that I decided to test the effects of emphasizing stealth mode
          on
          > mileage.
          > > Where I live, we have innumerable hills so finding a long
          stretch
          > of flat
          > > road is not easy. I decided however, to take roads that I knew
          > were less
          > > "hilly," and which also had a lower speed limit, which would
          > enhance my
          > > ability to enter into stealth mode. I noticed that on
          relatively
          > flat
          > > terrain, as long as I stayed at or under 40 mph, I would almost
          > always enter
          > > into stealth mode. Regrettably, this meant that I might
          > inconvenience some
          > > people because I was driving just a bit too slow, but in the
          > interest of
          > > experimentation I decided to give it a go. Anyway, the roads
          that
          > I took
          > > were almost free of stop signs or stoplights for long periods.
          > Normally on
          > > these roads, while going at my normal pace, I can get five
          minute
          > intervals
          > > of 55 mpg according to the bar on the consumption screen. This
          > time though I
          > > had an astonishing number of high readings. My first high
          reading
          > was at 85
          > > mpg, and then as I entered into town, which has a very slow
          speed
          > limit of 30
          > > mph, I received readings of 100 mpg--the highest that the
          > consumption screen
          > > will allow for!!! I then got one of 95 mpg and yet another 85
          mpg
          > on the
          > > five minute interval display!! Now let me tell you about the
          > effect it has
          > > had, at least apparently, on "real" fuel economy.
          > > Now, there has been some discussion on this list about
          the
          > variability
          > > of the Prius fuel gauge readings, due to the bladder tank, in
          > registering
          > > accurate fuel consumption. My car is fairly accurate, however.
          > For example,
          > > I have averaged 44.87 mpg so far and that is done by calculating
          > fuel fill
          > > ups in gallons vs. mileage driven. Not surprisingly, the first
          bar
          > typically
          > > disappears between 40 and 48 mpg, with the largest cluster
          coming
          > in at 44
          > > mpg. What however has been the effect of utilizing stealth
          mode?
          > Well, I
          > > really can't say yet, because I still have not had my first bar
          > disappear and
          > > I am at 83 miles so far (I push the rest button at every fill
          up,
          > and then
          > > calculate miles driven vs. fuel entered at the next fill
          > up)!!!!!!!!!!!! All
          > > of this has led me to believe that if I prudently route my
          > destination so
          > > that I can maximize the number of flat roads and lower mph I can
          > enhance the
          > > ability to enter into stealth mode, thus enhancing my fuel
          economy
          > > considerably. However, I need to ask the mavens of battery
          > technology what
          > > this sort of reliance, or should I say over reliance, would have
          on
          > battery
          > > life? Certainly, it is heady wine to be getting somewhere over
          83
          > mpg by
          > > constantly driving off the batteries. I would love to continue
          > this sort of
          > > driving style for I could easily raise my mpg average up past
          50.
          > What
          > > however are the effects on the batteries? Any ideas from
          anyone?
          > Would this
          > > style of driving cause premature battery failure? In any
          > event, "stealth"
          > > driving is awesome, so long as the driver does not mind going a
          bit
          > slower.
          > > Cheers
          > > Bill
        • wmhpowell
          ... Perhaps in YOUR Prius, but most of the rest of us have Mr. Fusion in the trunk! ... The energy stored in the HV battery pack comes from only 2 sources :
          Message 4 of 10 , May 1 7:58 PM
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            --- In toyota-prius@y..., "scouterpmphx" <pmenconi@c...> wrote:
            > Since "stealth" energy comes from the gas engine,
            Perhaps in YOUR Prius, but most of the rest of us have Mr. Fusion in
            the trunk!
            :-)

            > I'm not convinced it is an ideal mode.
            The energy stored in the HV battery pack comes from only 2 "sources":
            MG1 and MG2. It is the conditions that cause the MGs to produce
            charge that matter however.
            - When you cold start Prius, the ICE runs in the adabatiac mode to
            heat the cat system. It produces more power than it usually needs to
            run the car so - eny extra power that causes MG1 to charge the
            battery is, in escence, FREE; if we didn't capture it, it would
            otherwise be thrown away.

            - When you brake to a stop, MG2 (potentially) produces charge
            current. Yes, you bought and paid for that momentum with precious
            gasoline and pollution BUT - if you HAVE to stop, why not recapture
            some of that FREE energy in the form of electricity and recharge the
            battery.

            - When you let up off the gas pedal (or whatever you want to call
            thet sensor under your right, or left - depending on location, foot)
            you are declaring that you intent to loose some of that expensive
            momentum. Again, MG2 will recapture some of that FREE energy and
            pipe it back to the HV pack.
            If you do this while going downhill - WHEEEeee - LOTS of FREE
            energy. The alternative is to pick up a LOT of momentum, and speed,
            and wind up paying an expensive and NOT FREE speeding ticket.
            :-)

            Even of the HV pack looses, wastes, leaks, throws away almost ALL of
            the charge obtained from FREE sources, it's still a net gain when
            compared with the <Koff..> alternative.

            bp
          • young95014
            ... ... destination so ... enhance the ... I don t doubt that you are getting better MPG than your original route and driving pattern. Your post
            Message 5 of 10 , May 2 8:39 AM
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              --- In toyota-prius@y..., Ameradian1@a... wrote:
              <snip>
              > of this has led me to believe that if I prudently route my
              destination so
              > that I can maximize the number of flat roads and lower mph I can
              enhance the
              > ability to enter into stealth mode, thus enhancing my fuel economy
              > considerably.
              <snip>

              I don't doubt that you are getting better MPG than your original
              route and driving pattern. Your post seemed to imply that going into
              stealth is the reason. However, so many things are different that it
              would be difficult to say which one is the dominant one. Lower speed
              may contribute. Flatter roads may contribute. I said "may" because
              someone is sure to point out that he could do better in hilly terrain
              than flat grounds with certain technique.

              Playing scientist in real life means we should change one variable at
              a time. A difficult thing to do!
            • Zerby, Chris (STP)
              Just a quick comment from a lurker. You don t have to only change one variable at a time. There is a practice generally called DOE, for Design Of
              Message 6 of 10 , May 2 9:29 AM
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                Just a quick comment from a lurker. You don't have to only change one
                variable at a time. There is a practice generally called DOE, for Design Of
                Experiments, where you can change many variables simultaneously. You DO
                have to know what variables you are changing/controlling and you DO have to
                use the right analysis to interpret the data. As you rightly said in your
                post, there are many things changing in the driving example, and those
                things need to be understood and accounted for. Sorry, couldn't resist
                dispelling the old "one variable at a time" way of thinking.

                Chris Z. (engineer)

                -----Original Message-----
                From: young95014 [mailto:young95014@...]
                Sent: Thursday, May 02, 2002 10:40 AM
                To: toyota-prius@yahoogroups.com
                Subject: [toyota-prius] Re: THE POWER OF STEALTH!!!!

                --- In toyota-prius@y..., Ameradian1@a... wrote:
                <snip>
                > of this has led me to believe that if I prudently route my
                destination so
                > that I can maximize the number of flat roads and lower mph I can
                enhance the
                > ability to enter into stealth mode, thus enhancing my fuel economy
                > considerably.
                <snip>

                I don't doubt that you are getting better MPG than your original
                route and driving pattern. Your post seemed to imply that going into
                stealth is the reason. However, so many things are different that it
                would be difficult to say which one is the dominant one. Lower speed
                may contribute. Flatter roads may contribute. I said "may" because
                someone is sure to point out that he could do better in hilly terrain
                than flat grounds with certain technique.

                Playing scientist in real life means we should change one variable at
                a time. A difficult thing to do!




                To unsubscribe from this group, send an email to:
                toyota-prius-unsubscribe@yahoogroups.com



                Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
              • Bryan Underhill
                Remember, wind drag is a squared function of the velocity. I would propose that the fantastic figures you see are more from reduced speed than being in
                Message 7 of 10 , May 4 8:11 PM
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                  Remember, wind drag is a squared function of the
                  velocity. I would propose that the fantastic figures
                  you see are more from reduced speed than being in
                  stealth mode. A speed increase of 50% from 40 mph to
                  60 mph increases the wind drag by 125%!


                  --- Ameradian1@... wrote:
                  > So many people have discussed the value of stealth
                  > mode on previous posts
                  > that I decided to test the effects of emphasizing
                  > stealth mode on mileage.
                  > Where I live, we have innumerable hills so finding a
                  > long stretch of flat
                  > road is not easy. I decided however, to take roads
                  > that I knew were less
                  > "hilly," and which also had a lower speed limit,
                  > which would enhance my
                  > ability to enter into stealth mode. I noticed that
                  > on relatively flat
                  > terrain, as long as I stayed at or under 40 mph, I
                  > would almost always enter
                  > into stealth mode. Regrettably, this meant that I
                  > might inconvenience some
                  > people because I was driving just a bit too slow,
                  > but in the interest of
                  > experimentation I decided to give it a go. Anyway,
                  > the roads that I took
                  > were almost free of stop signs or stoplights for
                  > long periods. Normally on
                  > these roads, while going at my normal pace, I can
                  > get five minute intervals
                  > of 55 mpg according to the bar on the consumption
                  > screen. This time though I
                  > had an astonishing number of high readings. My
                  > first high reading was at 85
                  > mpg, and then as I entered into town, which has a
                  > very slow speed limit of 30
                  > mph, I received readings of 100 mpg--the highest
                  > that the consumption screen
                  > will allow for!!! I then got one of 95 mpg and yet
                  > another 85 mpg on the
                  > five minute interval display!! Now let me tell you
                  > about the effect it has
                  > had, at least apparently, on "real" fuel economy.
                  > Now, there has been some discussion on this
                  > list about the variability
                  > of the Prius fuel gauge readings, due to the bladder
                  > tank, in registering
                  > accurate fuel consumption. My car is fairly
                  > accurate, however. For example,
                  > I have averaged 44.87 mpg so far and that is done by
                  > calculating fuel fill
                  > ups in gallons vs. mileage driven. Not
                  > surprisingly, the first bar typically
                  > disappears between 40 and 48 mpg, with the largest
                  > cluster coming in at 44
                  > mpg. What however has been the effect of utilizing
                  > stealth mode? Well, I
                  > really can't say yet, because I still have not had
                  > my first bar disappear and
                  > I am at 83 miles so far (I push the rest button at
                  > every fill up, and then
                  > calculate miles driven vs. fuel entered at the next
                  > fill up)!!!!!!!!!!!! All
                  > of this has led me to believe that if I prudently
                  > route my destination so
                  > that I can maximize the number of flat roads and
                  > lower mph I can enhance the
                  > ability to enter into stealth mode, thus enhancing
                  > my fuel economy
                  > considerably. However, I need to ask the mavens of
                  > battery technology what
                  > this sort of reliance, or should I say over
                  > reliance, would have on battery
                  > life? Certainly, it is heady wine to be getting
                  > somewhere over 83 mpg by
                  > constantly driving off the batteries. I would love
                  > to continue this sort of
                  > driving style for I could easily raise my mpg
                  > average up past 50. What
                  > however are the effects on the batteries? Any ideas
                  > from anyone? Would this
                  > style of driving cause premature battery failure? In
                  > any event, "stealth"
                  > driving is awesome, so long as the driver does not
                  > mind going a bit slower.
                  > Cheers
                  > Bill
                  >
                  > To unsubscribe from this group, send an email to:
                  > toyota-prius-unsubscribe@yahoogroups.com
                  >
                  >
                  >
                  > Your use of Yahoo! Groups is subject to
                  > http://docs.yahoo.com/info/terms/
                  >
                  >


                  __________________________________________________
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                • young95014
                  I certainly agree that changing one variable at a time is not the only way to go. It is not even the preferred way all the time. Thanks for the reminder!
                  Message 8 of 10 , May 13 5:44 PM
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                    I certainly agree that changing one variable at a time is not the
                    only way to go. It is not even the preferred way all the time. Thanks
                    for the reminder! Nevertheless, I think we agree that the conclusion
                    drawn in the original post may be somewhat of a leap.



                    --- In toyota-prius@y..., "Zerby, Chris (STP)" <chris.zerby@g...>
                    wrote:
                    > Just a quick comment from a lurker. You don't have to only change
                    one
                    > variable at a time. There is a practice generally called DOE, for
                    Design Of
                    > Experiments, where you can change many variables simultaneously.
                    You DO
                    > have to know what variables you are changing/controlling and you DO
                    have to
                    > use the right analysis to interpret the data. As you rightly said
                    in your
                    > post, there are many things changing in the driving example, and
                    those
                    > things need to be understood and accounted for. Sorry, couldn't
                    resist
                    > dispelling the old "one variable at a time" way of thinking.
                    >
                    > Chris Z. (engineer)
                    >
                    > -----Original Message-----
                    > From: young95014 [mailto:young95014@y...]
                    > Sent: Thursday, May 02, 2002 10:40 AM
                    > To: toyota-prius@y...
                    > Subject: [toyota-prius] Re: THE POWER OF STEALTH!!!!
                    >
                    > --- In toyota-prius@y..., Ameradian1@a... wrote:
                    > <snip>
                    > > of this has led me to believe that if I prudently route my
                    > destination so
                    > > that I can maximize the number of flat roads and lower mph I can
                    > enhance the
                    > > ability to enter into stealth mode, thus enhancing my fuel
                    economy
                    > > considerably.
                    > <snip>
                    >
                    > I don't doubt that you are getting better MPG than your original
                    > route and driving pattern. Your post seemed to imply that going
                    into
                    > stealth is the reason. However, so many things are different that
                    it
                    > would be difficult to say which one is the dominant one. Lower
                    speed
                    > may contribute. Flatter roads may contribute. I said "may" because
                    > someone is sure to point out that he could do better in hilly
                    terrain
                    > than flat grounds with certain technique.
                    >
                    > Playing scientist in real life means we should change one variable
                    at
                    > a time. A difficult thing to do!
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