I believe I have determined that 34 mph is BOTH, the speed at which EV mode automatically disengages, if you have the EV switch and have used it to engage EV mode, AND the speed at which the car will transition from Stage 3a to Stage 3b operation. (For those who have not followed my speculations dividing S3 operation into two sub-modes, S3a and S3b, S3b operates exactly like Stage 4 (full hybrid) operation, but is triggered by reaching 34 mph rather than by a 10-second full stop, and S3b reverts to S3a if you apply the brake below 34 mph.)
I'm not sure I can agree with you, Daniel. Almost every day, I turn off my main highway onto the stretch to work. I speed up to around 40 and let up. Then I feather all the way to work, about 200 yards, without dropping speed. There have been times when I've had some real difficulties getting the EV to engage at any speed. Or perhaps it's more accurate to say that I can't get the ICE to disengage. I end up having to let up on the gas, coast a bit and then feathering on the EV. I figure I'm still learning.
you always speak of these stages and in no techinical doumentation of the HSD or THS systems have I seen refernaces to stages, would you please explain or give me a link?
The car will not necessarily go into golf-cart mode in either S4 or S3b. Depends on all the factors the computer uses to decide. And it may be that we don't even know all those factors. So being in S3b does not guarantee that you can "feather" it into electric. "Feathering" encourages the car to go electric, but does not force it. I also have times when I think I should be able to "feather" it into electric, and it won't go. Then I just either let it be, or use the EV switch. Also, if you are in S3b and you apply the brakes below 34 mph, you'll be back in S3a. My assertion is merely that 34 mph is the transition speed between S3a and S3b, and that in S3b the hybrid system functions the same as in S4, with the computer sometimes deciding to run the car in golf-cart mode. (And we already know that 34 mph is the speed at which EV mode is automatically cancelled.) BTW, if you quit feathering the pedal entirely, and just drive it, it will still go into golf-cart mode on its own, generally not too much later than you could have feathered it into it.
I'm surprised the number isn't 42. :crazyeyes: On the other hand, the Hitchhikers Guide to the Galaxy didn't mention the Prius at all. And perhaps the Japanese engineers have not read it. /Paj
Tha explains what it is in relation to this thread, but I would like an explanation of these stages you speak of, have you got a link, or will you explain here?
It is out there in some PriusChat thread. It needs to be cleaned up and posted in the FAQ or Knowlege Base.
However - the speed at which stealth mode ends all together (w/o the EV switch) *is* approx 42mph - at this point the ECU will kick on the ICE to prevent overspinning of MG1. So perhaps they *have* read it (or at least seen the movie).
Are you guys talking indicated speed, or actual? I've found an 8% overread in mine (it gets distance right, as judged by Trip A over a measured mile).
http://priuschat.com/forums/viewtopic.php?...highlight=stage not as exciting as it sounded to the unkowing
I will write an account of my understanding and observations of the stages, and submit it to Danny for inclusion in the knowledge base. It may need to be peer-reviewed first. Several Japanese posters have given us authoritative-sounding, but not always consistent, explanations, and I have added my observations. But I forget the temperatures of the various transitions.
Thats an EU legal requirment I think you will find. All cars must read 7% over real speed to get the EU certification.
I have posted a draft of an article on the 5 stages of hybrid operation HERE. I woulod appreciate comments and corrections. Please post them as replies to the article. Thanks.
OK I probability misunderstood all of this, but I am sure that I saw my prius running on electric i.e. Battery to ME2 to wheels at 65 mph on I 90 on what appeared to be a flat at the base of Fourth of July Pass in Idaho. I cruised along for a few (3-5) miles on EV. Did I misunderstand?
The 8% overread doesn't exist in the US - I can be reading 50mph and drive by the radar speed limit signs and be at 49-50mph indicated by radar.
Henry: If there were no arrows leaving the engine, then what you saw was "super golf-cart mode" (formerly known as "super-stealth" by those who like the militaristic-sounding terminology). The ICE is spinning, but it is not providing any power to the wheels. You are indeed running on electric. But the ICE must spin, due to the geometry of the PSD, otherwise MG1 would turn faster than its design limit. It would amaze me if you went 3 miles that way. Overcoming wind resistance at 65 mph on the battery's power alone would drain your SOC pretty fast, and at 65 mph the ICE is efficient and would be favored by the computer. Are you sure there were no arrows leaving the engine? Normally in highway driving there will be arrows leaving the engine, and the arrows between battery and MG will go back and forth.
I, too, drove I-90 last week over Fourth of July pass and the others and regularly saw no arrows coming out of the ICE, even when going 70-75. On smaller hills, it was only for a few seconds, but often there clearly was no arrow and MPG showed 99.9 for periods.
<div class='quotetop'>QUOTE(swepri\";p=\"39554)</div> i though maybe this was a thread on rolling rock beer, but that's 33... :mrgreen:
