I'm wondering if someone or several someones out there w/CAN-View would be interested in doing some testing of the voltage and amperage thresholds that trigger ICE start up in the speed range from 20-40mph. I'm thinking you need a long fairly flat area where you can maintain steady speed Starting at about 20mph document your battery SOC, have the display showing SOC/Amperage/Battery Voltage and probably MG2 and battery temp as well for completeness. If you can do a reset on one of the displays showing "Min/Max" that might help too, otherwise a passenger/documenter that understands what they're doing woiuld work. Do a run in stealth and try to see at what exact amperage threshold the ICE kicks in when accelerating from 20mph at a given SOC. Repeat for various SOCs from ~45% (about the lowest you can get EV mode to engage) to about 80%SOC...you can go higher and lower if conditions allow too, but you'll only be able to get numbers for stealth trigger points since you won't be able to engage EV. Anyone game? How about one of your local group meetings a couple of experienced folks make a project of it? Basicly I'm interested in seeing what the difference in threshold points is. My gut tells me it's some fixed threshold no matter what the SOC is IOW you'll stay in EV, once engaged, until you hit a -100amps draw at every SOC. Whereas in the normal operation stealth the threshold varies in a linear manner. At 40% SOC it may be -10amps to trigger ICE start up and at 80%SOC it may be 100amps. I'd really like to do this myself at some point, but I can't think of a good place where I could consistantly test and don't really have anyone to help me with data logging. Note that it may not matter what the speed is at all...it may be solely SOC dependent. Also, any other study design suggestions or parameters that should be monitored/recorded are openly welcome. What say you my peeps!? Who wants to justify all the money they spent on the CAN-View!
I have the place to do it. Its an access road to a dam. Its about a 2 mile stretch mostly flat. Some people use it at night to see how fast they can go. I've been meaning to go there to test out a few things with my car. Not speed because cops like to hang around that area. The stretch is mostly used by joggers and bikers. It sits along side the highway so its easy access. There is hardly anyone on it so low speed tests are perfect. I just have to find the time to get over there on a nice day.
<div class='quotetop'>QUOTE(efusco @ Apr 21 2007, 04:49 PM) [snapback]427506[/snapback]</div> I'd love to Evan, but I just don't have a long enough flat area where I live. That's probably my biggest problem in terms of repeatability of any experimentation I do. Dave M.
It's my understanding that there is a pair of semi-fixed throttle positions, one for stealth at about 25% and one for EV-Mode at about 50% (just rough guesses here on the %). In addition to that voltage is used in EV-Mode to trigger an exit at <180v. Stealth unlike EV-Mode is rather SOC sensitive. If you have a CAN-View then you should be able to bring a laptop and log your trips which will give much better results than trying to manually log things on the fly. You might be able to use something like the cruse control to "mark" events during your trip in the logged data stream. To get an idea of what is logged you can take a look at some of mine, the graphs represent only a small portion of the many data points in the zipped up spreadsheets. http://www.eaa-phev.org/wiki/PiPrius#Logs L8r Ryan
<div class='quotetop'>QUOTE(D0li0 @ Apr 21 2007, 09:24 PM) [snapback]427671[/snapback]</div> How do you get the data from the CAN-View to to PC? Through the USB programming port? Dave M.
I've got plenty of flat roads, but no safe way to log data while driving. Also, I suspect that battery temperature is a factor, but we have no way to control that. Just have to start testing with it cold, and keep testing as driving heats it up. In summer there's no way to test a very cold battery, and in winter it takes a very long time (if at all) to test a very hot battery.
<div class='quotetop'>QUOTE(dmckinstry @ Apr 22 2007, 06:54 AM) [snapback]427729[/snapback]</div> There should be a serial port (DB9) on the CAN-View, but I think that port may be an option so it may not be there. There are a few more links to other discussions about logging with the CAN-View here http://www.eaa-phev.org/wiki/CAN-View#DataLogging L8r Ryan
Evan - I just went and gave it my best shot. But try as I might, I can't get the ICE to kick on. Not with full-throttle acceleration at 50kW. Now with cruising at 80mph. Not after an hour on the freeway. I think something is broken in my car. I can't even fit any more gas in the tank after 45,000 miles. Oh! You meant in the Prius! Never mind. (Ok, not that funny, and more than a little annoying - but I've got a good coffee buz going, and it seemed like fun at the time). I'm done. I'll be good.
<div class='quotetop'>QUOTE(darelldd @ Apr 22 2007, 01:31 PM) [snapback]427858[/snapback]</div> VERY FUNNY!! One day Darell, I'll meet you and blind side you with a 2x4 just for the collective good of the entire PC community!! Luv ya babe...
<div class='quotetop'>QUOTE(D0li0 @ Apr 22 2007, 11:21 AM) [snapback]427855[/snapback]</div> Thanks for the link Ryan. I'll take a better look at it when I get a chance. Dave M.
<div class='quotetop'>QUOTE(efusco @ Apr 22 2007, 01:15 PM) [snapback]427902[/snapback]</div> Probably not surprisingly, that's the nicest thing that anybody's said to me today. I'm getting all misty... give me a moment....
<div class='quotetop'>QUOTE(darelldd @ Apr 22 2007, 05:57 PM) [snapback]428036[/snapback]</div> The 2 x 4, or the Love ya? Dave M.
I've had a CAN View V3 installed in my 04 car for just about a month now. Alas, I have no location where I could consistently and safely take reliable observations. I have, however, been asking myself similar questions. I'm semi-convinced that there's a multi-variable calculation going on that varies the threshold, depending upon the particulars at the moment. SOC, throttle pos, and coolant temp seem to be involved. I'm trying to see if I can tell what else is invovled as well. On a semi-related note, I find that the CV graphic screen, and the color-coded throttle pos indicator is worth its weight in gold for keeping the car in stealth mode as long as possible. As soon as the blips turn yellow, I know it's time to back off just a tad, thereby keeping the stealth going as long as I can. I customized my "primary" display to show rpm, coolant temp, mpg, and charge, and with those four indicators, along with the throttle pos have allowed me to get a much better handle on when the car will fire up the ICE and when it won't.
