I think most states have coasting deemed illegal. So you have that to think about as well. And yes, you are wearing the CVT by doing this.

 

Well, I do have a tremendous amount of respect for folks like Bradley Berman (the owner of Hybridcars.com) but one thing we have to remember is that no matter how well meaning these folks and the content of their web sites are, we as readers and consumers, have to remain sceptical or this "free" information.
These are not authoritative sites in automotive engineering and as such the reader should be cautious and ask questions.

I agree with the statements made in this thread (strictly from a technical standpoint): Switching between N and D while in motion will cause unnecessary wear on the CVT transmission - This is not speculation. The best approach is to avoid doing it. Instead use the glide facility built into the HCH2: it is safer ... and more effective from a FE perspective as well.

Cheers;

MSantos

 

Noflash,
I read the article, and here's what I'm pretty sure is going on:
The article was primarily written for the HCHI. Some clues - it sites Hot Georgia as a main contributor. He has an excellent primer on HCH driving tips in this site under the Learn section. But his tips are based on what he drives, an HCHI. While there are many, many things the same between the first and second generation cars, the valve sealing technology while coasting is only on the HCHII, thus comments such as you are siting were really aimed at the HCHI.

Another clue is that the article refers to the instantaneous mpg gauge going all the way to 120 mph. That may be what it reads in the HCHI, but as you know, it only reads to 100 in the HCHII.

Finally, there are several instances in the article where they refer to the HCHII, but admit they "are currently evaluating" it. I think this article was probably written about the time of the HCHII's emergence, and just hasn't been completely updated to include the differences.

There are lots of threads from 9 months to a year ago on this site that discuss putting the car in neutral, shutting the engine off, rebooting the computer, and then coasting down long hills. While no one in their right mind would recommend this practice, it is a hypermilling technique, though a very dangerous one. This technique may have been useful on the HCHI, but it probably wouldn't buy you much, if anything, on the HCHII, again because of the valve sealing technology. But if you read some of those old posts, before the advent of the HCHII, they just refer to the HCH in general, because there only was one version at the time.

A long winded response, but I hope this makes sense. As msantos indicates, it is difficult to keep all articles on a site completely up to date and correct when new technologies come along.

 

Why do you consider this a "very dangerous" technique? BTW, the hypermilers refer to it as an FAS (forced auto-stop). The technique can still offer fuel economy benefits in the HCHII. The bottom line is that you will coast better in neutral. If you turn the engine off while in neutral, you can see advantages. From experience in my HCHII, FASing is clearly better for coasting than coasting in gear while feathering the gas pedal to prevent charging. However, it is not a technique I use much in my HCHII. I have too many stoplights and I need the car on to get regenerative braking.

 

I think it's dangerous in that if all of the sudden you need power due to road conditions you won't have it as instantaneously if you're in "N". My first car was old and idled pretty badly such that I would glide it in "N" almost at every stop light and have on occasion forgot to put it back into "D" when the light turned green (especially if I was just about to come to a complete stop when the light turned green). This really sucked as I had to wait for the engine to come back down before going into "D". Maybe this isn't so much of a problem for people used to driving stick.

 

It sounds like it could be a "somewhat" dangerous procedure... I know that with the engine off you have a few applications of the brake before the vacuum bleeds off and you lose power braking. What about steering? The HCHII has an electric power steering pump. Doesn't that shut off with a forced auto stop? Then there's the issue of accelerating quickly if you have to... a three step move (key on, tranny into "D", romp on the gas).

I'd only do it on an empty road!

 

The power steering kicks back in after a few seconds. Even if power steering wasn't available, it isn't that necessary in the HCHII. A more important question is whether the airbags work during one of these forced auto-stops? Does anybody know the answer to that?

For many people, using the FAS technique can offer huge fuel economy improvements. As with many ways to improve fuel economy, there is an underlying cost (wear and tear on a component, hybrid premium, etc.). These are things that people need to consider. It will vary from person to person and vehicle to vehicle.

 

FAS is not safe, you need to know what you are doing in order to perform this action well. Don't kid yourself.

 

Please elaborate. I like to hear other people's opinions, but your post says nothing.

 

I don't disagree with Livvie's statement at all. While some folks may be able to perform FAS safely (and correctly) it is a procedure that is not condoned by many State and Provincial governments and therefore often deemed illegal.

I have no doubt that if a well-meaning hypermiler ever got into an accident while performing FAS (at fault or not) he/she would be smart enough to not mention the procedure on the accident report.

Also, because this is (inherently) a public forum, our advice carries a burden of responsability that projects beyond our preferences and afinities. Promoting FAS without a mention of safety and appropriateness disclaimers can amount to supporting the procedure - at least in the eyes of some folks who may be willing to try anything for a few more MPGs.


Cheers;

MSantos