Thanks Carl,

This is exactly the engineering information needed for every vehicle. I've been collecting engineering data about my NHW11 and sharing it in the Prius specific forums. I've been using these data points to check the Toyota reported, specific drag formula:

But I've been disappointed that the P&G advocates don't provide a good model for either steady-state or P&G performance. Instead, it remains at best 'an art'. BTW, the equivalent 34 mph average, P&G and steady state data are on this chart.

The five horizontal blue lines are 25-43(34)P&G and the five blue dots are cruise control 34 mph. Later, I found there was a bias on the direction of my benchmark runs and the P&G had three favorable and two unfavorable direction runs. The cruise control tests had two favorable and three unfavorable runs. This means the graph difference is likely greater than it it is in 'real life.' I have no problem sharing this data since all speed management used the built-in cruise control to handle everything from acceleration through the glide.

I also have 15-23(18)P&G and 18 mph steady results that strongly suggests that 18 mph steady is much better than 15-23(18)P&G. But I'm not ready to publish this data until I can repeat the test in a controlled environment.

Bob Wilson

 

This seems to suggest the GH milage database is inadequate because the graphs of your choosing are not there. So the time, distance, and speed is not enough? My 25-mile commute to work takes about 35 minutes with some P&G at the ends, and about 80% of a steady cruise at about 50mpg in an urban area. If I thought I was discussing this with a dispassionate mind, I'd pull out the graph generated by CarChip.


This picture (from Bob's personal site) is not associated with a story by a 3rd party on hypermiling and this thread is in "Anything Goes" - not a technical forum - sounds like a neutral viewpoint just seeking the truth? Reminds me of when you waited until the Insight Marathon was over before demanding a graph, Bob.

In my career, I've been with other programmers that have customized their knowledge base, graphs, etc. to give their point of view a distinct "home field advantage".

In a Captain Ahab way. Laurie, myself and others do lot of other things besides P&G and you insist on misrepresening it. I've noticed the few times you have posted this stuff on PriusChat it's pretty much ignored.

Have you contacted ibrands with your objections about them interviewing hypermilers in Baltimore/DC and Sioux City, IA?

 

It's coming, as described in this thread. Now that I have decent instrumentation, my testing is back up and running. It's slow going with my busy schedule, but I should have some initial results within a few days.

 

<LOL!> I can just see it now. 20 or 30 hypermilers in a "convoy" during the morning commute in the Interstate HOV lane doing a flaming 43 to 22 MPH -- all close drafting -- and alternating the lead like a flight of geese. Newspaper headlines, helicopter TV hookups, and the state police al la a bad Burt Reynolds movie.

Sorry, thie visual image was just too much and I had to post it.

 

'scuse me, but what a bunch of horse hockey. comments like that, coming from someone who actually drives a hybrid, does nothing to promote improving fuel economy. some days, when reading your posts, mr. wilson, i really wonder where you are coming from.

as a matter of fact, the day that the AP hypermiling article hit the web, there was a rash of forums calling "people like us" names, and degrading our efforts to make people aware that we can help reduce our usage. very strange to have to read the same kind of remarks on a forum that is supposedly promoting hybrids.

 

Hi,
LOL! A rolling road block of "environmental terrorists." Don't forget the baggies of ice in our pockets and seats and driving in bare feet. Yet that image seems to be a common lament based upon a quick survey of recent threads:It is a question of perception and the types of reactions we see pretty well proves the point:
This reputation has and remains an objectively verifiable fact that extreme, even ticketable techniques have painted all "hypermilers." A slander? Sure but a common perception to the point I'm not sure it can be reversed. So my postings are to also address what we should call ourselves.

It is a problem of semantics and my nod is "efficient drivers" because:

1. efficient - impossible to argue against
2. drivers - emphasizes responsibility

In contrast, "hypermiler" has two problems:

1. hyper - implies excess, a negative as in 'hyper active'
2. miler - implies a long distance, to be endured

Make no mistake but semantics are important. For example the "estate tax" was branded the "death tax" when in fact it is the "Paris Hilton tax." We can lament the reputation attributed to "hypermiler" but we can not ignore that it exists. We are not the ones who have to be convenced.

Bob Wilson

 

What to call ourselves, a question that is anything but trivial. More difficult becuase we are not a homogeneous group. Each of us is here because of some combination of these elements, but not necessarily for all of them:

1. Automotive Technology;
2. Fuel Ecomonmy and Performance;
3. The environment and a proactive stance to same;
4. PAC to push manufacturers, either for further performance or in different directions related to 1-3 above;
5. And probably a few more that I missed, including some with purely social aspects.

I suspect we do need a name for the more moderate elements amoung us. Let's face it, the majority of the motoring public is not going to install block heaters (Unless the mfrs do) or run with ice to save a few miles. We should still warmly invite them to embrace hybrid technology becasue it is in our own interests individually and as a group. Otherwise, we wouuldn't be spending time on this forum.

 

OK - call me a geek - i am a numbers guy and an Empiricist, though I would like to become a hypofueler.

I probably wont go to the extremes that some will to maximize FE, but I certainly am interested in data that sheds light on: 1) important factors affecting FE and 2) comparisons of important driving techniques. Then, I plan to apply these learnings to improve my FE and hopefully help others who want to do the same.

Bob, Jimbo - when running P&G vs steady CC tests, will the steady CC potentially get penalized at the "end" of the test run FE-wise since it is maintaining say 34mph, while the P&G has slowed to say 24mph, but with a segment FE benefit. The steady 34mph is carrying more kinetic energy at the end of the test? Or do you allow both to glide down to say 24mph at the "finish" line?

 

Hi,
I just like to see the vehicle performance optimized as the default. Then any falloff in performance can be used to look for potential mechanical problems.

That is why my focus is on getting usable engineering data about everything from the tires to the tank and the air filter to the tail pipe. BTW, this data doesn't have to be perfect but good enough to give reproducible results.

I used complete, full P&G cycles. I would enter the course at the lower glide speed, 25 mph for 25-43(34)P&G, and upon start, use the cruise control to accelerate to 43 mph. Then I would 'suspend' cruise control and when the speed reached 40 mph, put the gear in "N" for the glide. The 3 mph delta ensures the ICE turns off. Using "N" gives a ballistics glide to 25 mph where I would engage "D" and hit 'resume' on the cruise control. At no time in these tests did I manually operate the accelerator. For my tests, I would do as many complete cycles, ending at 25 mph as I could, typically five each way, and then use the MFD to read the results.

Of course cruise control at a steady 34 mph was much easier and I would typically end where the last P&G cycle completed.

I also did some 15-23(18)P&G tests versus 18CC but at these speeds I could not use the cruise control. I had to accelerate using the accelerator and also manually maintain 18 mph for the steady state runs. I would prefer to not publish any definitive results because of the manual processes. However, the recorded data suggests the energy expended to start and stop the engine played a significant part in the results.

Bob Wilson

 

Hi,
This is exactly right! My investigations are aimed at improving the vehicle technology and letting folks have a 'road map' to how to get more performance within their comfort skill and budget limits. I'm just after efficient driving including the hardware, software and operator skills.

Some of these changes are trivial: (1) 3/4 oil level, (2) highest acceptable tire pressure, and (3) route planning. Some take a little more work: (1) getting the wheel alignment right, and (2) avoiding unexplained AC and heat loads (aka., a default defrost setting.) Finally, there are those changes that require mechanical skills: (1) engine and transaxle heaters, (2) battery systems, and (3) low back pressure muffler.

Bob Wilson