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Car Forum / Toyota / Prius / April 2008What is the "optimum driving style" for mpg?
My '04, purchased in late '03, has about 52k miles on it and has averaged about 43mpg since new - less in winter, more in summer. I'm in S Calif, so "winter" is a period on the calendar rather than a season. 90% of the time there's just me aboard, so I benefit from the HOV sticker! The tires are inflated properly (+2psi) and the wheels are aligned. I envy those who consistently report 10-20% better mileage than I have attained, and suspect that the deficiency is in my driving. My "technique" is to stay off the brakes, doing a lot of coasting and careening around corners, on the theory that neither regen nor friction braking are as good as using kinetic energy to continue moving. That means I must take my foot off the gas as soon as it becomes evident that the car will have to stop. What else can I do to improve mileage? Thanks, Lon Ranger > My '04, purchased in late '03, has about 52k miles on it > and has averaged about 43mpg since new - less in winter, [quoted text clipped - 14 lines] > must take my foot off the gas as soon as it becomes > evident that the car will have to stop. I think the most important key is to keep your speed as steady as possible, neither accelerating nor decelerating quickly (light on the gas, light on the brake.) It isn't necessary to drive very slowly, and in fact it seems that moderate acceleration yields better results than driving like a tortoise. If you see a that you need to slow/stop for traffic, a traffic light, etc. start to slow as soon as possible. If you can keep moving, so the traffic starts moving before you catch up to it, is the ideal. On the highway slowing down a bit, say from 75 to 65, will make a difference. As far as careening around corners, I think you'd be better off slowing down a bit, allowing the dynamic braking to recover some energy. Yes, I know a lot of folks will say regen isn't close to 100% efficient, but it doesn't have to be. When you turn, you're losing energy to a number of forces. A change in direction is a form of positive acceleration, which takes energy. And if you have any wheel slip, that's also wasted energy (not to mention the wear on your tires.) So slow down enough that you can take the corner easily, then slowly accelerate again after the corner. My 2¢ "Lon" ... > My '04, purchased in late '03, has about 52k miles on it and has averaged > about 43mpg since new - less in winter, more in summer. I'm in S Calif, so [quoted text clipped - 16 lines] > > Lon Ranger Hi Lon, Here is what I do that I believe gets me more MPG. As much as I can I try to get it to run in stealth mode at all speeds. All speeds on flat or downward slopes. To do this I use what I call PriusFoot. I get up to my speed and then lift the foot off of the pedal for an instant. This shuts the motor off. Then I lightly press on the gas pedal again only so much that it engages the battery drive, but not the engine. This takes a trained foot and it took me a bit to get it reliably right. I do it without thinking now. I do it as much as I can. I am almost always generating more electricity than I use, so I try to use as much as I can. Tomes > "Lon" ... >> My '04, purchased in late '03, has about 52k miles on it and has [quoted text clipped - 33 lines] > electricity than I use, so I try to use as much as I can. > Tomes I can "force" electric drive in either of two ways. For example, I installed a red LED that illuminates only when the fuel pump is ON. I could add a switch to the circuit that powers that pump, but the total energy in the traction battery is about equivalent to a martini glass full of gasoline. And, of course, there's Pin 27. I'll discover that "Priusfoot" thing today and see if it's feasible without becoming an obstacle to others. Thanks! Hi yo, Silver! >> "Lon" ... >>> My '04, purchased in late '03, has about 52k miles on it and has [quoted text clipped - 46 lines] > > Hi yo, Silver! I'm really not sure that it is a good idea to "force" the electric drive. The car has several primary directives built into it's management systems and one of the most important (so I read) is to manage the battery for long life. I'm not at all convinced that dragging every spare watt out of it (deep cycling) on a regular basis will do it a lot of good. Why not just drive the thing and let it look after itself, as designed. Early battery failure is likely to be the alternative outcome. Chas >>> "Lon" ... >>>> My '04, purchased in late '03, has about 52k miles on it and has [quoted text clipped - 56 lines] > > Chas PriusFooting works within the bounds of the battery maintenance protocols designed into the car, it just maximizes return. Tomes <text snipped for brevity> >> I can "force" electric drive in either of two ways. For example, I >>> installed a red LED that illuminates only when the fuel pump is ON. I [quoted text clipped - 22 lines] > designed into the car, it just maximizes return. > Tomes No real problem with that - it was the idea of wiring in fuel pump cut-outs, etc that prompted my response. Chas > My '04, purchased in late '03, has about 52k miles on it > and has averaged about 43mpg since new - less in winter, [quoted text clipped - 7 lines] > mileage than I have attained, and suspect that the > deficiency is in my driving. You are driving your car like a normal car, like everyone else on the road drives, and that's fine. You're getting good mileage. If you want to get what those other people are reporting, you can (a) lie (like most of them), or (b) start driving very, very weirdly and in the way in traffic. Do you want to be the dweeb who's screwing around in traffic, playing his dashboard video game? > <snip!> > > I envy those who consistently report 10-20% better [quoted text clipped - 10 lines] > Do you want to be the dweeb who's screwing around in traffic, playing > his dashboard video game? I am doing neither a) nor b), and average well over 50 MPG. (actual fuel use vs. miles driven, not based on the MFD.) I'm sure a big part of that is my commute is 36 miles each way. As mentioned before, one of the MPG killers are short trips, since MPG is poor in the first 5 minutes or so of driving. So on a short trip that will be a significant factor in the overall mileage, whereas on a longer (45 min-1 hr) trip, it's largely offset. My tires are at 40/38 psi, which I check regularly. I block my grill to varying degrees depending upon the weather, and I use an engine block heater year-round, which is a big help with the initial mileage. I don't drive in a way that impedes traffic. In fact, I've noticed that if I get behind a particularly slow driver, my MPG actually suffers a bit (based on the MFD history.) I accelerate smoothly, try to keep a steady speed, and begin to slow down as soon I see I'm going to need to stop ahead. I DON'T do the pulse & glide (which is I think what was being referred to here as 'PriusFoot'. In fact, I engage the cruise control as much as possible. I do try to maintain stealth or warp- stealth on long downgrades, but never slowing to the point where I'm below the speed limit if someone is behind me. In fact, it usually isn't necessary to slow down... just a light touch on the throttle. The only drivers I seem to piss-off are 1) ones that apparently think everyone should be doing 10+ over the speed limit, and 2) the idiots who think you need to race up to the stopped traffic as quickly as possible so that you can jam on the brakes. Then again, I've encountered such drivers long before I started driving a Prius. The fact is, I've always had sports cars or sporty sedans, and my driving style was to go as fast as I thought I could without getting a ticket (radar detector was required equipment.) Now that I stick to the speed limit, I find I'm much more relaxed, and even long trips don't take significantly more time. You can choose to assume I'm exaggerating the mileage I'm getting. I'm just hoping that I can help others improve their MPG, since it *is* possible to regularly get over 50 MPG without resorting to stunt driving. "Mr. G" ... > Elmo P. Shagnasty ... >> <snip!> [quoted text clipped - 50 lines] > possible to regularly get over 50 MPG without resorting to stunt > driving. I think that this is all very well said and reflects my perspective. Tomes > My '04, purchased in late '03, has about 52k miles on it > and has averaged about 43mpg since new - less in winter, [quoted text clipped - 3 lines] > sticker! The tires are inflated properly (+2psi) and the > wheels are aligned. It would help to see a printout from the last alignment check. The rear wheels are 'fixed' but can be adjusted for less toe and camber to reduce rolling resistance. How many miles are you getting from the tires? Also, I run my Sumitomo tires at the maximum sidewall pressure, 51 psi but my route is on good streets at urban speeds. The oil level is about 1/2 to 3/4 between the fill and full marks. > I envy those who consistently report 10-20% better > mileage than I have attained, and suspect that the > deficiency is in my driving. Not necessarily so. > My "technique" is to stay off the brakes, doing a lot of > coasting and careening around corners, on the theory [quoted text clipped - 4 lines] > > What else can I do to improve mileage? We don't have enough information. If you can provide two Google Map 'addresses' that show your normal commuting route, we might be able to suggest some things to test. Route planning pays big dividends _IF_ there are fuel efficient alternatives you can use. Bob Wilson >> My '04, purchased in late '03, has about 52k miles on it >> and has averaged about 43mpg since new - less in winter, [quoted text clipped - 33 lines] > > Bob Wilson Just imagine two locations six miles apart, level ground, with four lights. Light traffic in the morning (I arrive later than most), heavy in the evening. I coast up to red or reddening lights, and barely touch the brakes. As for the alignment printout - I have no clue nor any inclination to do it again. Seems to me that 51PSI is a huge number! I wonder what the difference in MPG would be using the rolling resistance at that PSI vs prescribed, on Brown's computer. Someone commented regarding my "careening around corners." 50 years ago I raced for a living, and loved it. Such driving might not save much gas, but it brings back memories. Thanks for the input. Lon Ranger > Just imagine two locations six miles apart, level > ground, with four lights. Light traffic in the morning > (I arrive later than most), heavy in the evening. I > coast up to red or reddening lights, and barely touch > the brakes. Something like this: http://hiwaay.net/~bzwilson/prius/map.jpg > As for the alignment printout - I have no clue nor any > inclination to do it again. As you wish. > . . . Seems to me that 51PSI is a > huge number! I wonder what the difference in MPG would > be using the rolling resistance at that PSI vs > prescribed, on Brown's computer. http://hiwaay.net/~bzwilson/prius/pri_tire_010.jpg But whatever works, GOOD LUCK! Bob Wilson >> . . . Seems to me that 51PSI is a >> huge number! I wonder what the difference in MPG would >> be using the rolling resistance at that PSI vs >> prescribed, on Brown's computer. > > http://hiwaay.net/~bzwilson/prius/pri_tire_010.jpg That's impressive. I might pump 'em up until I feel a significant difference. Thanks! >>> . . . Seems to me that 51PSI is a huge number! I wonder what the >>> difference in MPG would be using the rolling resistance at that PSI vs [quoted text clipped - 5 lines] > difference. > Thanks! I run mine at about 40-42 psi (depending on how often I remember to check them). Tomes |
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