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Need engineering questions to ask during Volt test drive event this weekend...

7K views 19 replies 8 participants last post by  MrEnergyCzar 
#1 ·
I got an official ticket to the 2 mile Manhattan Volt test drive with engineers in the car and wanted 3 unanswered questions to ask the engineers that you guys would want an "official" answer to.... Miles per KWH is answered, tanks size I think we know, so I want some good questions to ask. 3 questions.

Thank you so much.

Peter
 
#2 ·
I pulled some questions from the other thread, you guys think of everything. I love the question about what happens when you open the gas cap when the Volt is completely out of gas.....

Thanks
Peter
 
#3 · (Edited)
The source of regenerated charging current? Does the large motor change over to a generator for all the regen current? Or does the smaller motor/generator give regen current by disconnecting the ring gear from the frame and allowing the ring gear to turn this generator thru the second clutch; (while at this same time disconnecting the clutch to the ICE)? Would the main motor have to be given a slight reverse torque to force the ring gear to turn for this regen path? Do the clutches play a larger role in the power distribution than we may first envision?
 
#5 · (Edited)
No one has weighed in with a response to this question. The more I think about it the more I believe that the small motor/generator is used for regen. I quess that a 3-phase AC motor like M1 would create a back emf that could be used as regen but how do you split the windings arrangement to achieve this. A 3 phase converter feeding a single DC output? I assume M1 has permanent magnets. How about M2? Does M2 act as a DC motor/generator, never running as an AC motor? Or do both motors have two sets of elctronics, one for the power direction and one for the regen direction of power flow.

I saw in Popular Science where GE is using a variable speeed Wind turbine without a gearbox to turn a permanent magnet generator who's output is conditioned by electronics for 60 cyle high voltage output to the grid.
 
#4 ·
You could try asking at what particular times is the ICE not supplying torque to the wheels in the CS mode?.. the engineer probably wont know the answer since its complicated and probably you should not trust what they tell you anyways..

An important easy question is: what motors in the Volt use permanent magnets and wich dont?.. Volt has a big motor, main traction motor, a smaller 53kw generator motor, a motor that drives the hydraulics in the transmission, a brake motor, AC motor, a couple of coolant pumps, power steering motor and so on.

Another simple question is: how long can the Volt sustain self-cooling of the battery pack while in long term parking (give them a location, summertime in Washington DC etc).. a couple of days, a week?

What are the maximum SOC limits of the battery pack, the actual charge points?.. as an example is the pack discharged to a minimum level of 20% and charged up to a maximun of 85%?.. or perhaps 25% to 90%?
 
#17 ·
I asked my Volt dealer person, who is attending the live Volt training this week, to ask these questions.....I'll let you know if they get answered.

Thanks
 
#7 ·
I believe we decided that the beauty of GM's transmission was that it could use both MG's for regen braking.ie in normal mode it uses the main traction motor and in L it uses both.
 
#10 ·
Incredible drive and an hisotric moment for me. Driving through the streets of Manhattan with silent ev power and torque is an erie feeling that everyone should do at least once in their life.... I was surprised by the fit and finish, especially the leather appointments, the hidden exhaust pipe, the LCD screens, and the back seats have room if the driver is 5 foot 9 like me.....all my questions were answered except what the EMI/EMF reading were, the engineer guy will find out from someone and get back to me on the EMF numbers. It is unknown if the Traction control can be turned off and there isn't a set ev mileage number drop that will invoke a battery warranty claim but the cells are constantly monitored so the cell history will show any drastic changes.... There is no scenario where the ICE will kick in if there is still a charge in the battery left, even during steep inclines and hard accelerations. You were right that if you charge it only in 110 for many years versus 220 for many years, the battery life will be exactly the same. It is hard for me to believe that but the logic is that the battery won't go into the damaging low SOC band or very high SOC. The LCD screens automatically dim at night and you can technically gain electric charge by putting into mountain mode and then back to normal but that would waste fuel. It appears the most efficient mode is the L or regen mode if you are driving in surburbia. The engineer said he got 52 EV range in normal mode and 42 while driving rather hard in the sport mode.... They didn't know which states/dealers will get the first allocations so my volt could technically come anytime from December through next summer. The radio does get HD channels. The battery does not go through any battery recalibration like another regular hybrid goes through. The vampire power after the volt is fully charged pulls the same power as 3 glade plug-ins... Does anyone know what the draw for a glade plug in uses? This is an odd reference. George, if the draw is too high, like 80 watts and I use a timer to shut off the vampire draw after it's charged, will the range be less when I go to drive the car just a few hours after the timer shuts the vampire load?

Thanks
 
#9 ·
Here's a question I asked at the Volt test drive, and got no answer. When the ICE is connected to the planetary gearset through the motor generator, what percentage of the power at the output shaft is derived from mechanical sources (ICE) and what percentage is derived from electrical sources?
 
#12 ·
That's the one thing that caught my eye from this report too. Great, HD Radio!
 
#15 ·
The engineer could have been confused with HD radio versus XM radio as he was reading and answering a long list of questions... I didn't see it on my order printout with all the car's features from the dealer either so this HD radio goes in the questionable category...
 
#16 ·
Yeah, I was suspecting that to be the case. I think we need to get someone who already knows what HD Radio is, and knows some of the local stations to test with, to try to tune them in.
 
#19 ·
That may be the most accuracy-free set of answers I've ever seen.
 
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