CAN View Users (Charge/Discharge Limits)

oic, ok maybe backwards then the neg one is the one on the bottom of the formatted screen. its the one with the generally higher RPM figure. so MG1 would be smaller of the two then?

 

Yes MG1 is the one that goes plus and minus mostly. MG2 is tied to the wheels.

Not sure it will help with when EV mode switches off. I think that is best seen with amperes and you need to adjust the levels for battery temperature and maybe SOC.
Engine will always come on well before the max current limits in my experience but this limit does vary with battery temp.

Generally I look for 20 amperes when very cold, 30 when warmer and maybe to 50 when quite warmed up. Limits are maybe 50 cold and then over 100.
EV button allows more amperes before engine start. Still the full limits are more likely reached when flooring the accelerator I think.

But pushing accelerator too fast even a little bit also triggers engine on.

I think MG1 may prove most useful on highway to see the torque and economy points. Not sure yet. Just got my update loaded.

Still working on this as my SSC50P update has clearly changed the limits. I can regularly go up hills with engine off that I could not do ever before! And engine off mode works at like 20 deg lower temperatures too than before for a given amount.

 

haven't looked at the formatted screen in a while as I have set the text 1 screen to have

amperage
rpm
MG2
MG1
throttle
gas gauge

currently that's what displays when the car first starts up. I did look at the formatted screen to check the min max results but don't nomally look at it unless something piques my interest. I change the text screens to suit my current interest. I should actually change the text 1 screen to have instead of gas gauge the ICE temp and will probably set it to that next time I use her car.

 

On the MG1/2 topic, here's my reference numbers.

MG2 is purely a function of road speed. It will vary with effective tire diameter (and so the load in the car and tire pressures) but not by more than maybe 2-3%.
So as its supposed to be limited to 6000 rpm, that works out to be ~105 mph which is about what Toyota claim is the Prius top speed. You'll note when they did the 130mph Prius test, they kept the same MG2 limit by just putting on bigger tires. (Which of course needed more HP from the tweaked engine to get it to 130 mph)

MG1 peaks at +10,200rpm for me under acceleration from standstill. And also at -6900 rpm so far, but its not clear what produces this other lower peak.

On the odd discharge limit topic, I've been waiting for it to be warm enough to try an experiment. When warm, one limit (that I've called charge) peaks at 105 amps, while the other limit (that I've called discharge) peaks at 125 amps. So the experiment is, if you get the car warm and stable with these two limits reached at clearly different levels, and then accelerate/brake which current corresponds to which limit? You can't try this cold because the 2 limits are then roughly the same. Well its now warm enough (and wet enough!) to try here on the Wet Coast.

What I saw was maximum discharge of 125 amps and maximum charge of 102 amps.
That says to me the charge limit IS the smaller one, because if it wasn't, it would have limited the discharge current to less than 105 amps, not the 125 amps I saw.

Which means despite it being logical that reaching a high SOC would cause a drop in maximum charge, that can't be what is happening. I am going to guess that what is being observed is the battery reaches a high state of charge and gets hot and the battery ECU says, I'm going to let the battery cool off, so I'm going to prevent high discharge currents for a while by dropping the discharge limit way down and I'm already preventing further charging by having switched to 'B' (engine braking) mode.
And I'll remove these temporary liimits just as soon as the battery has cooled off a bit.

But its just a theory....

 

you with EV can on the set up screen change the box with the 3 dashed lines to 3>>> and that will give you the throttle amount on the second user graph screen that you can input before the ICE starts. It comes on as a line of >>>>>>>>>> and when the ICE starts it turns red. It'll give you a fairly wide line of >'s before it triggers.

 

I was driving around today and the battery temp was about 100F. The discharge limit was -125 and the charge limit was 100. I was able to steadily draw -120 in EV mode without the ICE coming on. So it seems like the limits are labeled correctly.

 

just got back and MG2 speeds i tracked

2800 RPM=50 mph
3050 RPM=55 mph
3300 RPM=60 mph
3575 RPM=65 mph (probably should be 3550 to match the pattern here.)

also, have to question the discharge and charge limits being related to SOC...not seeing that yet. will have to observe a bit more. is there a way to put charge and discharge on a txt page?

 

on the text page just push on what line you want the amperage to be on and CAN-view will take you to the setup section for that page push the A button and then push Save and it'll take you back to the text page and that line will show amperage +or-

 

actually im looking for the Max charge and Max discharge numbers. trying to see a correlation between that rate and gonna compare SOC first and then battery temps... or maybe both to see if either varies with those rates. the format screen is a bit too busy and hard to read more than one simultaneous reading.

 

I am going to have to make a retraction here. 'Frenchie' has pointed out this article:
http://prius.ecrostech.com/original/Unders...SplitDevice.htm
Whilst done for the Classic and so a different final drive ratio than the current Prius, the PSD gear teeth numbers, according to NERL, have not changed and so the equation for MG1 should still be (3.6 X engine rpm) -(2.6 x MG2 rpm)

I can't fault this article so will go back to the original calculation in CAN-view. So now I have to come to terms with seeing MG1 reaching 10,800 rpm, which is a lot higher temporary overshoot. But if that is the actual rpm, then so be it.

I will correct the numbers at the same time I post the version with selectable graphs for MG1 and 2, in the next few days.


Darn, I got it wrong....

 

thanks for the info. your formula does work with the data i collected yesterday (allowing for some read errors)
what i collected

RPM...MG2...MG1...calculated compare last two for error margin)

1300....0...4400....4680
950..1475..600..-415 (large downhill numbers jumping probably accts for errors here)
0...1250...-3400..-3250
0...1350...-3400..-3510
2350..3300..-300..-120
950..3300...-5400..-5160
2550....3250...0...730
2400...3325...-200...-5

can't wait for the new update...its like having a new toy to play with every other week!

 

If you guys want to check your RPM ratios, try the simulator. Even though the simulator is simulating the classic, the PSD ratios haven't changed, thought the RPM limit for MG1 has been raised to 10K from the original 6500 limit.
Would be nice if the simulator would show pwer input/output from ICE/MG1/MG2.
MG2 had an RPM limit? I hadn't heard that.

Also remember, not only do you have fixed RPM ratios, but you have fixed force ratios. From those 2, you should be able to calculate power ratios. Takes a lot of math though. I make too many derivation errors to do it myself.

 

ok Scott... i did see something that does lend so creedence to what you saw. situation was car still cold. going down long hill at 25 mph (State Street for those of you that know Olympia) SOC started at about 64%. discharge rate at 95 amps

SOC is up to about 68% then discharge starts to drop and fast. by the time SOC is at 72%. discharge is down to 5 amps. unfortunately, hit the bottom of the hill. (i was really bummed <_< )

so later on way back, same hill, different side. (going west to east is steeper shorter hill) saw SOC rise to 71% but discharge rate didnt change one iota. stayed at 98 amps all the way.

more than a little baffled by this. obviously, not looking at the right combo of indicators. so (ya wasting gas now... ) i get to top of hill, circle a 4 block turnaround route and go back down State Street again. this time, i get to 74% SOC and discharge rate still didnt change.

ok...ummm... any ideas?? only thing i can see that was different was the first time, the Prius was not warmed up completely. i had just left my house and the hill starts only a few miles away.

sooo... Scott, you may be on to something, but we need to be looking at something else too... any ideas?? im kinda lost

 

OK I have not been down that hill with the CAN-View but I have been down it a lot of other times. 25 mph and they patrol it, a lot. You keep your speed down or else. I have been at 7-8 green on several occasions in the past. I usually cruse around the "filled in tide flats" of Olympia in EV mode and then up the hill a bit. It is a very nice hill for filling the battery!

 

Evan, what an excellent find! Thanks. Much more than this feeble brain can consume but extremely interesting. Next time around I think I'll become a mathematician, engineer, and master a Palm pilot. I can work an abacus tho'
gary

 

120-125A as a maximum discharge limit sounds exactly right given the published performance figures. The engine is known to be 57kW max, and the max power is consistently quoted as 82kW, which leaves a 25kW shortfall to be made up by battery output. And 25kW/201.6V = 124A.

 

I'll just add a note on the MG1/2 feature. I'm not afraid to admit while I read the article on the Prius planetary gearbox and the math made sense, my brain couldn't quite catch up with the idea. With it continuing to niggle away at my brain xcells, I made a 'gearbox' up out of styrofoam cut to a blown-up template from that article, with just 1 pinion gear as multiple pinions don't affect ratios.

Then with the 'ring' held stationary (car stopped) I twirled it around by hand and counted the number of sun (MG1) revolutions for 1 complete planetary (engine) revolution.
Yup, 3.6:1

Why is it you can trust your eyes more than your mental ability? Or is that old age creeping up?
[attachmentid=1761]

PS: I rate this 'gearbox' at ~1/millionth HP with a warranty of about 2 minutes.....