View Full Version : One week with the Prius PHEV prototype
Hey guys. Finally got a time-slot on the Prius PHEV prototype.
Let me know if you guys have any follow-on Q's to the previous run-ins.
05-26-2011, 03:56 PM
I have a couple of questions.
First question is: When the battery is completely charged, do you have to use it right away, or can you turn it off and on to save and use later.
05-26-2011, 03:59 PM
Jud, that's an excellent one.
How well does it respond to hypermiling techniques in EV mode? Can you get 30 or 50 or 80% better, or is there not much extra to gain with no ICE running?
Also, how about some details on glide mode and the speed limits involved.
First few observations:
1) ICE flipped on at 65 mph on the highway, but I didn't have IGN up so I don't know if the battery was pulling in around, or if the injectors were actually squirting fuel.
2) It was 102F when I was charging in in my driveway. The inverter (under the passenger seat was HOT!!, not burn your finger hot, but hot enough for your body to flinch away from it. I found it because I heard the inverter fan running full blast.
3) Your are locked into EV between 100 SoC and 25% SoC. There lower threshold may be higher than 25% but I wasn't quick enough to catch the switch over.
Interestingly... they pulled the EV button off. It was on the mule I saw a few months ago but it is off of this one. Any of the early PHEV testers know how consistent the EV de-pop is?
It takes 3.5 hours to charge off of a standard 110/120 V. Think it's probably 5-6 kWh LiOn pack.
05-26-2011, 11:26 PM
When in EV mode, when does the engine kick in under load. In other words, how hard do you have to punch it to get the ICE to come on.
On a really long downhill, can you regen back up above 25% or whatever EV kicks out at.
The design of the first prototype (and possibly this one) was a logical 2-pack design.
Pack 1 = PHV pack - It gen's from AC, and provides all power, while it's got charge.
Pack 2 = Conv pack - When your on this pack, your a "normal" Prius"
Pack 1 = Soc of 80+ to about 26.
Pack 2 = SoC of 26 or below.
Once you transition to Pack 2, pack 1 is offline. Al the regen in the world won't get you back up above 26. Now to qualify this... Two points. This is a prototype, and they may have changed from the first mule I had to this one. Just guessing.
1) 105f in Texas today... No crazy thermal issues to speak of. Inverter still runs the fan high when charging in the heat.
2) Full Charge SoC = 80.3
3) Miles on EV at full charge projected at 14.0
4) Today's Miles achieved on EV = 19.2 (37% above projections). I had depleted (logical) pack 1, the HSI flipped over to the normal partitioned display with a line where the ICE will start. This is your only indicator that (logical) pack 1 is offline.
5) pack 1 DOES regen as long as it is still online. It is VERY hard to see since your only indicators are MoE and SoC.
6) Once you get to about 36 SoC (or 2 MoE) the Prius S1 stage is enforced. The engine kicks on to heat the CATs. They likely do this in anticipation of a HW state, where driving full speed on the HW, it would take 2 miles of time to do the 60 second mandatory CAT heating. Once you get into the margin state, S1 is triggered every time you start the car.
7) Once on pack 2 the standard Prius Stages are observed (with the exception of S1 since you've already navigated that in (6)).
196.15 MPG @ 107.78 Wh/mi
Right Lane Cruiser
05-28-2011, 12:11 AM
So really it was 19.2mi on electric @ 194.79 Wh/mi and 15.5mi @ 87.62mpg ?
05-28-2011, 05:47 AM
You talk about 2 packs. Is there just one actual battery and it is partitioned, or is there two actual packs. Also have you looked at the physical battery and do you think the current Gen III is upgradable by putting the new battery in it.
Sean... Kinda.... That is the general ballpark.
There are times in PHV-EV mode where the engine comes on and burns gas (the S1 mandate) and there are times in HV mode where I'm running off pack. So it's hard to make a hard partition between the two... But for ballpark figuring yes, those figures are about correct.
The first mule actually had 3 packs. Pack 1 and 2 were for EV, and pack 3 was for HV. The three were physical packs that were brought online / offline by the ECU.
I've looked at the pack. It might fit in a regular prius, but there is new firmware. It definitely uses a unique Battery ECU.
One thing I've noticed is that SoC at full charge is different, and that the kWh drawn during charging is different. I would expect these to be pretty constant. If the pack is really physically partitioned three ways, and if the AC charger only charges 2 of the three partitions, this could explain why the SoC is different, since your charging two packs but summing SoC on 3.
-The forced S1 does happen when less than 2 miles are left on EV. The exact point is when 1.6 mi are left and and SoC of 32.5.
-The transition from PHV to HV happens at an SoC of 26.2 with 0.0 mi left on EV.
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