P&G or steady state driving?

[VABeachPrius]

There are those that demonstrated the capabilities of the gen 2 prius with the prius marathon (krousdb, xcel, and others come to mind) and those that have shown graphs of steady state mileage (bobwilsonforweb?); equally with impressive results. Thank you.

Has anyone ever come to the conslusion that one method yields higher mpg's WITH a higher average mpg. I was thinking about this while driving to work the other day at 21 mph (for the most part steady state neighborhood roads) and ended up with 106 mpg on the scan gage after 21.7 miles. Albeit slow, steady state is much less stressful than watching the scangage RPM, traffic on the road, instantaneous mpg during a pulse, watching the tenths section of the trip meter, traffic on the road, gliding, etc. Maybe I'm lazy, but I seem to just drive a slow steady state speed and anticipate traffic and still have mid 60's to mid 70's averages.

More rhetorical I guess, sorry.

[steviet]

Originally Posted by VABeachPrius

There are those that demonstrated the capabilities of the gen 2 prius with the prius marathon (krousdb, xcel, and others come to mind) and those that have shown graphs of steady state mileage (bobwilsonforweb?); equally with impressive results. Thank you.

Has anyone ever come to the conslusion that one method yields higher mpg's WITH a higher average mpg. I was thinking about this while driving to work the other day at 21 mph (for the most part steady state neighborhood roads) and ended up with 106 mpg on the scan gage after 21.7 miles. Albeit slow, steady state is much less stressful than watching the scangage RPM, traffic on the road, instantaneous mpg during a pulse, watching the tenths section of the trip meter, traffic on the road, gliding, etc. Maybe I'm lazy, but I seem to just drive a slow steady state speed and anticipate traffic and still have mid 60's to mid 70's averages.

More rhetorical I guess, sorry.

I hope this doesn't come out wrong, but really? 21mph? Is that the posted speed limit?

[donee]

Hi VaBeach...,

I have only a few places where traffic will tolerate 21 mph steady state. And one way on my commute I am on the highway at 53 mph, and the other way pulse-and-glide, with lots of lights. In this weather (80 to 90 F), I am in the high 60's consistantly for the whole tank. I had another 70.1 mpg tank recently.

On a pulse and glide portion I was up just above 70 mpg on the tank, after just starting the tank, and at the end of each glide the result was a few tenths higher. Indicating the actual P&G mileage was well above 70 mpg. And this was only a 40/35 mph P&G. In another instance, I had a really poor tank going, and in one run pulled it up significantly. When I got to my destination I took the time to figure out the mileage for that pulse and glide and it was 77 mpg. The main reason was allot of lucky light timing. That resulted in the trip actually being 10 minutes faster than normal, or 27.6 mph average , instead of 23.4 mph average.

[JimboK]

Hey, stranger, where ya been?? Good to hear from you again.

I don't do much steady state driving these days, though that's in large part due to road and traffic conditions. I'm frequently accelerating and decelerating anyway for red lights, stop signs, and traffic, so I'm P&Ging simply to do it all in the most efficient way possible. Where there is an opportunity to choose between P&G and steady-state, I choose the former because of the abundance of anecdotal evidence pointing to it as the better method. Two examples, the first from last summer and the second from this summer:

90+ MPG trips. (Oh, how I love summer fuel mileage!)

97 MPG commute ... aiming for 100!

I'm currently pushing for my first 80 MPG tank, though it might be a struggle with some of my non-commute trips generally in the upper 60s or low 70s. It's currently at about 79 MPG, 300+ miles into it, 1 pip gone.

Few have done controlled tests comparing the two methods. Bob Wilson did so in his Gen I and got comparable results with the two methods, IIRC, using cruise control both as his steady-state method and his method of pulsing. We can't necessarily extrapolate those results to the Gen II. Besides the drive system differences, CC used as an acceleration tool in the Gen II easily pushes ICE RPM into what I consider inefficiently high ranges. I've wanted for some time to do a test, but for a variety of reasons (mostly related to life) I've not done so.

[VABeachPrius]

No, the speed limits were 25 and 35 mph for most of the route. I was on the way to work after normal working hours and was called and told that I didn't have to be there until later. Since I was close, I slowed down to experiment and kill time. It would have been a waste to go home and drive back again.

I am at the far end of the spectrum when in comes to MPG's. I won't even bring up my tire pressure. I am a very observant and respectful of others driver.

Jimbok,

I am fine. Did you get married? How are things with you? I saw yours and skywire's pictures in the FHOP thread. That's a neat thread. I will have to post my picture.

I took a year off from posting here and at cleanmpg.com. I was having a "I can afford a used 2007 750LI BMW phase, why am I driving a prius?" time in my life. It turns out that one shouldn't let machoness or emotions rule what type of car you drive. I am re-learning to like my car again. I still have my M5, but I think its days are numbered. Getting poor mpgs in any car has become unacceptable with what the Prius can do. Apples and oranges to compare the cars, but the technology is there.

Congrats again donee, I saw your thread where you had a 70 mpg post. Some combination of pumping your tires up, slowing down, anticipating traffic, and your route make it easier for some than others. I am fine tuning what I do, but driving 1800 miles a month makes it hard to drive slow.

I am leary of the 2010 for its lack of no arrows gliding. Is it silly to worry about that? Someone will figure out what the equivalent is for a gen 3. It looks like the ecometer will be useful for accelerating at optimal RPM. I sat in one at the dealer the other day when my car was in for service and it looks to be a little better quality than my 2006. When I roll past 300,000 miles, I will buy another unless BMW has a high FE car like the prius.

[JimboK]

Things are well. Not married yet; we're in no hurry.

As for the Gen III's fuel economy capabilities, ordinary drivers seem to be getting the expected 10% improvement over the Gen II. For those that push the envelope, the envelope doesn't seem to have moved much, if any. Wayne Gerdes' parents bought one and he has had some opportunity to drive it. His comment in post #39 of this CleanMPG thread:

"... those that are pushing high FE with their –II’s would be disappointed in the –III imho."

Kinda makes me glad I didn't pull the trigger when I had the chance to a few months ago.

[VABeachPrius]

After reading that post, I wonder if the Gen 3 prius is better than the gen 2 for the masses not hypermiling. But when it comes time to maximize FE, the Gen 2 is still king.

Do you think that once someone cracks the code of the Gen 3, that the Gen 3 will take the title of max FE machine. I agree with xcel in his comments.

Back to the originial point of this thread, it appears that with P&G and steady state, that I can acheive 100+ mpgs in a Gen 2. I was hoping that the maximum in a gen 3 driven in a similar way would be 108+ mpgs. One day maybe. Those at cleanmpg will find a way.

[donee]

Hi Vabeach...,

I am running 46/44 PSI, so not much tire pumping. Everything else you mention but route selection I have done without success. A long time ago (like 30 years) I learned how to anticipate traffic and time lights, not for hypermiling purposes, but to get around stoping and all the other drivers at lights. Its the same skill set, just applied differently.

What made the difference was the combination of route selection, and the MYCANSCAN teaching me SHM, and how to keep the engine in its efficient zone during accelleration. Knowing what route to pick was actually a result of watching the temps and trip time on the MYCANSCAN. The temp gauges showed that I was warming the car up over and over on some routes. Rather than having it warm all the way up and stay there, even if that was a slow warmup. And the trip timer pointed out how one route while slow speed limit route, got me to the same place actually faster than the other routes. So, in actuality, the main improvement can all be laid down to MYCANSCAN.

[FireEngineer]

Chris,

Don't forget that all of Bob Wilsons steady state in the Gen III are done with only the in car displays and no additional instruments. His Classic runs had the Mini-Scanner to instrument the tests. Take his Gen III results with a grain of salt. My own runs show P&G will be better than steady in most cases in a Gen III. Exception being where you live, nice and flat.

Wayne

[VABeachPrius]

Wayne,

Am I misreading xcel's first impressions of the Gen 3 in his cleanmpg thread? One quote comes to mind states that he averaged about 90 mpg in the gen 3 where the gen 2 would have been 100+? Is it that folks like xcel have not solved the puzzle on optimization of gen 3 high FE? It seems odd that a new car with a higher apples to apples epa rating cannot be pushed farther than the gen 2; at least yet.

While slow steady state speed is efficient, it appears that I don't fully understand the rpm band of most efficiency for the engine. On essentially a closed course I am able to drive steadily between 20-23 uninterrupted and can max the consumption screen. However, the engine may only be running at 1100-1300 rpm when it is running; outside of the 1500-1700 region I use during pulse and glide. It appears that depending upon the speed of the car the load on the engine changes and could in theory make the 1100-1300 rpm range efficient. It could also be at 20-25 mph air resistance is way down compared to 30-35 mph.

I guess I will have to p&g for a while and steady state drive and see what works for my commute.

As an aside after reading many threads about ev mode only, it is very difficult to spread the word that using extended EV operations is actually a detriment to high fuel mileage. It must be counterintuitive (SP?) to most.