I have multiple routes between home, work, dry cleaners, dog park, grocery store, and bar. There is no requirement to take the shortest or fastest or least efficient route. The earliest Prius 'marathon' drive ran loops around a partially complete Interstate. Later, I was castigated when I analyzed a Honda Insight (first generation) marathon drive and it only did laps around an Oklahoma section line. Also, I have a copy of a SAE paper that made claims about 'Pulse and Glide' on a closed track. If my use of a loop is a 'cheat' then every previous marathon drive falls in the same judgement. There are people who would object to calling such earlier efforts a cheat but I am not one of them. A "loop" is just another, poorly documented but consistent rule for marathon driving that ANYONE can and should apply. It is my fondest wish that my example of a "1000 mile tank" would be understood and copied by as many PriusChat owners as possible. Simply incorporate a high-mileage loop in your daily commute so at a cruise control setting of 26-27 mph, it take one hour for each trip. About 2-3 weeks later, announce your success. The last time I checked, the Japanese 1,000 mile tank club had nearly two dozen members. It is time we catch up. Bob Wilson
I promise I didn't mean to offend. Poor word choice by me and was purely shorthand for using roads that I might not otherwise drive that would be advantageous to good fuel economy.
No problem, I have been in a similar situation. Several years ago, a well respected Prius 'gray beard' had mentioned how they had 'force charged' their Prius to give press demos. I contacted him privately and suggested that 'sand-bagging' the press this way was not a good idea. He had a different point of view and I never brought it up again. In engineering, the problem is called "managing user expectations." It turns out that too often folks are willing to make inflated claims. When the customer 'buys-in' to it, they learn the truth and feel they have been deceived . . . cheated. A pattern of inflated claims erodes credibility and serious people tune them out. Over time, high mileage stunts are thankfully receiving less and less notice. News organizations that tried to make reports in the past often found the actual events were . . . not realistic or reproducible. That is why I prefer "efficient driving" that has a hard, reproducible definition and completely unambiguous. "Efficient driving" is not sexy, Rocket Science, or anything but mind-numbing boring. But it can be taught and mastered in a very short period of time including the most important aspect of all . . . cruise control set speeds of 26-27 mph. Bob Wilson
If one were to put their car on a dyno and cruise around with zero air drag for say, a CRAP TON of miles, would this be eligible? No I'm not trying to cheat nor do I know anyone with a dyno.. I'm simply curious. You could probably go dookie far that way too..Cruise control set to 28 MPH.. Let it do its thing.. Talk about an artificially high number.. You could probably make it to the thousands of miles! Of course, not really since you'd never actually leave the same place.. Just a caveat I thought of! Hah! I hope to post up some high MPG's here soon. I'm going to be honest though I haven't read through all 37 pages of this thread. Does the MPG count go by what is indicated, or what is calculated for your car? I'm not trying to falsely place higher than what I deserve, my particular car tends to be more generous with MPG estimation than by my Fuelly calculations.. Just wondering which number will be posted ?
Many years ago, someone did a marathon drive for a Honda Insight, the two seater. They did laps around an Oklahoma section line running 16-18 mph: So don't ever feel bad about the speed or route. It is all 'fair game.' We're using "indicated" (see F8L's reply) although we all know the calibrated numbers are different. Something I learned this weekend is the "indicated" numbers generate a true fuel consumption: indicated_miles / indicated_MPG. It is the tires-to-odometer that is in error so the indicated mph is also wrong. Bob Wilson
Very informational post, thank you very much for taking the time to write it! Your last comment on the indicated numbers is interesting, come to think of it I have in fact noticed a discrepancy with my speed which I now believe from your post is due to the tires which does make sense. The reason I noticed the difference was because locally they had one of those radar trailers. On my commute I placed my cruise control at 40MPH and the radar would consistently read 39MPH. I thought perhaps it was a threshold put in from the factory to help save you some $$ on a speeding ticket (i.e. the faster you go the larger the gap actually is from speeding indicated to actual speed.) <--Sort of a dumb way of thinking I suppose but I thought on the other hand "what the driver doesn't know won't hurt them" in that regard..
Mark IIRC the most fuel efficient speed for the electric motor on a regular liftback 3rd Prius is 15 mph. Is that also true for the Plug-in Prius' electric Motor - or does it have a higher *sweet point* with regard to speed? By *sweet point* I mean that given a fix power amount in kwh if you drive a PiP at a fixed constant velocity (no pulse and glide, no driving with load) on a close loop circuit ... one particular velocity rate goes the farthest distance given a flat road.
Most of us believe it is still 15 but that's more of a guess that anything. How much larger is the PiP MG?
My question is, if on a closed loop at 15 mph you will never get any regeneration. How much of a loss will that be? and does it really matter? When we drive normal and we get regeneration are we just making up for some of our already used energy? So there is never any gain, just less loss! Or sometimes depending upon the hills can we gain some EV miles? I get so confused.
How on earth do you get the mileage you get without knowing that, haha. In a perfect world you wouldn't have any regen because you wouldn't need it.
My earlier tests and models indicate the maximum range efficiency is ~18 mph but it falls off gradually. It turns out that in warm weather, we can easily achieve values greater than 99.9 MPG at 25 mph. If you'll check my description of 'efficient driving,' all it takes is setting the cruise control to 26-27 mph. Let the car climb any gentle grade at that speed. Upon hitting a downgrade and the car begins to pump energy into the traction battery, shift into "N" until it begins to exceed the speed limit or the speed decays to the cruise control set speed. Then resume cruise control managed speed. Bob Wilson
Ok, why so much buzz about pulse and glide if you can accomplish the same with normal cruise control and steady speed, or did you have a circle of only ups and downs, so the up was pulse with CC down was glide in N? Did the SOC ever drop to a point that ICE was forced to start? Your MPG is just unbelievable.
It never made sense to me and the non-engineering descriptions made no sense. Even Kansas roads have little rises and dips so nothing special is needed. I have access to two loops and even the second one has rises and dips. The second one is 'on base' and the security folks sometimes wonder about a car doin' laps. It was in the 2 and 3 bar range but the engine runs on the upgrades easily provided the charge needed. Let me suggest 'try it' and share your results. I had gotten 99.9 MPG before in my benchmark tests just using cruise control on flat segments that did not involve te cycling between "N" and "D". The "N" and "D" trick with cruise control alleviates the flat road requirement. The final trick came from our Japanese friends with the realization that once the car is fully warmed up, add miles in high efficiency mode, warm-up so they totally dominate the vehicle trip miles . . . say 10 times longer than the warm-up. Doin' laps at 99.9 MPG easily dominates the warm-up penalty. So my normal 10 mile commute comes in at 20 miles with the extra laps. If you want a simple rule of thumb, park the car each time with the MPG showing over 95 MPG or even 99.9 MPG. If it is not that high, keep doing laps. BTW, the laps can be done at the beginning or end. Bob Wilson
