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Re: THE POWER OF STEALTH!!!!

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  • scouterpmphx
    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:
    Message 1 of 10 , May 1, 2002
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      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
    • 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 2 of 10 , May 1, 2002
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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 3 of 10 , May 1, 2002
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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 4 of 10 , May 1, 2002
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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 5 of 10 , May 1, 2002
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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 6 of 10 , May 2, 2002
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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 7 of 10 , May 2, 2002
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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 8 of 10 , May 4, 2002
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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 9 of 10 , May 13, 2002
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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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