Glide mode over 40 mph

[timwalsh300]

Let me preface this by saying that I've driven about 3,000 miles in my Prius and I've experimented with all the various techniques described on this forum and other places - so I understand the difference between no-arrow gliding, green-arrow coasting with regenerative braking, and orange-arrow electric-only stealth mode.

But this is confusing me... by all accounts you can only achieve a true no-arrow glide when traveling under 41 mph; pressing the pedal lightly above that speed puts the car into stealth mode. Generally this seems to hold true.

However, I've noticed a few times that I can get a no-arrow glide when going much faster. Specifically, I was on the freeway yesterday towards the end of my trip doing 56 mph on a slight decline, and I found that if I touched the pedal ever so gently I could start gliding instead of being in the usual stealth mode. It was difficult to keep it there - a hair too much or too little and I went into stealth or regenerative braking - but I was able to hold it for more than just a few seconds. I could also get it back if I lost it.

Has anyone else seen this? Any idea what is going on?

Tim

[Rokeby]

timwalsh300,

I have seen this also, I believe that it is part of "Super Highway Mode"
(SHM). It is mentioned here with cites to a fuller discussion:

Prius Stages of Operation & Operating Mode Availability -A Reference Aid

SHM is an alternative to Pulse and Glide (P&G) for max MPGs at highway
speeds. It is particularly difficult to attain and hold due some variable pre-
conditions, such as State of Charge (SOC). I stumble into it now and then
and it's very exciting, though I loose it all too soon.

[Bob64]

I believe its akin to warp stealth, except in full glide... Very hard to accomplish. I do it all the time, while monitoring amps coming from the battery to get a feel for getting into I think I'll call it "warp-glide", for now, since I can't remember the proper term for it.

[David Beale]

It's just stealth below 66 km/hr (41 MPH) and warp stealth above. The warp stealth is very hard to get into as the "dead band" where it occurs is very narrow. I find a very flexible shoe sole is the best way to make it attainable (for more precise pedal control).
Above the 66 km/hr MG1 will be spinning the ICE but no fuel will be injected - to ensure MG1 is not overspun.

[bestmapman]

Originally Posted by timwalsh300

Let me preface this by saying that I've driven about 3,000 miles in my Prius and I've experimented with all the various techniques described on this forum and other places - so I understand the difference between no-arrow gliding, green-arrow coasting with regenerative braking, and orange-arrow electric-only stealth mode.

But this is confusing me... by all accounts you can only achieve a true no-arrow glide when traveling under 41 mph; pressing the pedal lightly above that speed puts the car into stealth mode. Generally this seems to hold true.

However, I've noticed a few times that I can get a no-arrow glide when going much faster. Specifically, I was on the freeway yesterday towards the end of my trip doing 56 mph on a slight decline, and I found that if I touched the pedal ever so gently I could start gliding instead of being in the usual stealth mode. It was difficult to keep it there - a hair too much or too little and I went into stealth or regenerative braking - but I was able to hold it for more than just a few seconds. I could also get it back if I lost it.

Has anyone else seen this? Any idea what is going on?

Tim

Hi Tim,

The Prius has two basic operating modes. Above 42 MPH and above, and belod 42 MPH.

Below 42 MPH: In this regime, the ICE will shut off and you can "glide" with no power coming from the ICE or MG2. The ICE is is not turning.

42 MPH and above: The ICE will always spin so as to protect MG1 from overspeeding.

The MFD display is an approximation of what is going on. If you want a more accurate indication of what is happening then you need to get an auxilary device like a scanguage or canview to get more accurate readings.

Because of the above conditions, a no arrow glide has a different meaning above 42 MPH then below 42 MPH. Above 42 MPH a no arrow glide only means that less current is being drawn from the battery. It does not mean the ICE is not turning, it is turning.

This is a very basic explanation, hope this starts your quest for further knowledge.

[9G-man]

Originally Posted by timwalsh300

....But this is confusing me... by all accounts you can only achieve a true no-arrow glide when traveling under 41 mph; pressing the pedal lightly above that speed puts the car into stealth mode. Generally this seems to hold true.

However, I've noticed a few times that I can get a no-arrow glide when going much faster. Specifically, I was on the freeway yesterday towards the end of my trip doing 56 mph on a slight decline, and I found that if I touched the pedal ever so gently I could start gliding instead of being in the usual stealth mode. It was difficult to keep it there - a hair too much or too little and I went into stealth or regenerative braking - but I was able to hold it for more than just a few seconds. I could also get it back if I lost it.

Has anyone else seen this? Any idea what is going on?Tim

Yes, everyone that monitors and understands the Prius' different modes of operation has seen this, it's kind of a warp glide. Basically no gas (althought ICE is recipricating), no electric. Very hard to achieve and harder to maintain, I make no effort to induce it. For all practical purposes, at speeds over 42 mph, the warp stealth (just yellow arrows) accomplishes the goal (no gas), and is quite easy to induce and maintain. And the resulting electric assist of warp stealth help to maintain your speed, which with the increased drag of those higher speeds, is usually desired. I can maintain 60 MPH, in a warp stealth, for over a mile on some stretches of highway that is slighly declined.
It's amazing what averaging infinity into your MPG can do to the numbers.
Those who understand this, get the most out of their Prius.

[a priori]

Very nice little thread. I like the various responses and the short, to-the-point explanations.

I had noticed the above-42 no-arrow position on occasion, but I found it very difficult to accurately predict -- and very difficult, therefore, to induce. I am now at about 15,000, so I had surmised this was happening when I had a high SOC, but I wasn't sure that it really was similar to the below-42 no-arrow glide.

Thank you to the various experienced PCers who have offered well-written posts on this topic.

[Sheepdog]

there are so may ways to play with our car. I love it.

[bbald123]

Originally Posted by a priori

I had noticed the above-42 no-arrow position on occasion, but I found it very difficult to accurately predict -- and very difficult, therefore, to induce.

I find the cruise control is quite good at inducing this state on level highway if there is no appreciable wind.

[DaveinOlyWA]

i get no arrow glide at freeway speeds all the time. the mileage is always reading something most of the time but it varies a lot. 100 to as much as 500 mpg and it only occurs when going downhill.

scangauge is not perfectly accurate in these situations, but it does provide enough info for a guideline. it does tell you if you are using gas or not and i think that gas situations in the 500 mpg range are probably rounding errors but who knows...

i just drive it...with a family in the car, it becomes too much of a distraction to hypermile effectively. plus now, i am not the primary driver of the Pri anymore (accounts for 2 mpg drop in mileage...but oh well)

the last tank was better because, let someone test drive Zenn for a weekend, then got it back and charger died, so was driving Pri a week. but now that Zenn is back, mileage will most likely go back down