Prius Prime Plus in my hands

Yet curiously they have a battery and power electronics in the Prime that easily achieves enough power. Since I've got my Prime, I see it as the prototype for a true, Gen-5 Prius that only lacks the expense of a plug-in port and AC-to-DC charger. If the Japanese Prius can have the 18 kW rear wheel motors, the traction battery and power electronics may already be there.

Until Toyota comes out with their next 'standard frame', I can see the Prius c, Liftback, and v as being the payload versions and the plug-in Prime as the one that has reduced payload because of the increased battery and charging electronics weight. In the meanwhile, I'll growl in the corner about the missing: (1) tow package; (2) built-in house voltage inverter, and; (3) rear wheel motors.

Now is the Prime perfect? No, as I would like a faster charge option, 30-32A versus the current 16A. Fast DC charging would be nice but the 40 kW one we have in Huntsville is pretty well matched to the 72 mi range BMW I3-REx and would be 'Godzilla meets Bambi' if applied to the Prime.

There is a version of the J1772 that also has a lower DC charging capability and that might be a better fit to the Prime. But of course that is all we need, another J1772 variant 'in the field' . . . NOT!

Bob Wilson

 

A schematic labeled "FIGURE 6.3 - DC LEVEL 1 SYSTEM CONFIGURATION" shows using the J1772 pins 1 and 2 for "(Core pins for AC & DC Charging)". Later they differentiate between "DC Level 1 200-500 VDC 80A" and "DC Level 2 200-500 VDC 200A".

I don't know of anyone in the USA market who implemented the DC L1 charging that uses just the J1772.

Source: SAE J1772™ OCT2012

Bob Wilson

 

I prefer to drive using dynamic cruise control all the time but noticed a difference between ECO, Normal, and Power. So tonight I did a short hill-climb:

1. Holmes & Fairway climb to Holmes & 14th St.
2. Preset cruise control to 65 mph
3. Start at 28 mph and hit resume
4. ECO ended 53 mph
5. Power ended 58-59 mph

This suggests these two modes may also have power limits. Also, this confirms a coupling between cruise control and driving mode.

The BMW 3i-REx has three, power limited modes that also moderate the climate control.

Bob Wilson

 

Tonight, I did some practice runs:

• 3.5 mi @30 mph HV mode, 107.1 MPG 44F, 0% SOC - 0.0327 gal
• 3.5 mi @30 mph CHARGE mode, 32.4 MPG 44F, +10% SOC - 0.108 gal

ANALYSIS
Due to the digital nature and small values, I'm automatically adding half the least significant digit as more likely true for the linear increasing values. For example, 3.5 mi could be 3.599 mi, it could have been just shy of rolling over. So I'll use 3.55 mi as a synthetic but more likely distance. I'll also do the same for the SOC, using 10.5% instead of the indicated 10%.

	metric	1st pass	2nd pass
1	miles	3.55	3.55
2	mph	30	30
3	mm.m	7.1	7.1
4	MPG	107.1	32.4
5	gal	0.0331	0.1096
6	SOC	0%	10.5%
7	SOC gal	n/a	0.0765
8	SOC%/gal	n/a	137.5% / gal
9	SOC 80% gal	n/a	0.592 gal
10	gal/SOC%	n/a	0.00727 gal / %

Test route

• start - 34.595042 -86.545609 W 563 ft
• end - 34.646224 -86.540009 W 607 ft
• Google Map shows it as 3.7 miles which is consistent with the known tire diameter based error

Bob Wilson

 

I'm not sure we gain much by converting the SOC% back into miles. My primary interest is the impact on the remaining gallon when putting a 'safety' charge on the traction battery AFTER the tank warming light comes on. Also, double checking my numbers. I have been known to make math errors.

Bob Wilson

 

Thank YOU!

I knew something wasn't right but I was too tired to figure it out. Should be good now.

Bob Wilson

 

I wanted to summarize the "CHARGE" mode data from my initial experiments:

• Parked "CHARGE" mode: Prius Prime Plus in my hands | Page 16 | PriusChat
  • Very low rate 0%->1% - edge condition, probably discard
  • ranges 0.008 gal/% -> 0.011 gal/% - could be my reading data badly
  • average 0.0094 gal/% - dropped edge conditions 0%,1%, 2% as highest risk
  • ~0.75 gallons -> 80% (limit of charge mode), ~1 gallon on 'low fuel'
    
  • ~0.94 gallons -> 100%
• Graph from parked "CHARGE" mode
  • 
• Predicted 30 mph "CHARGE" effect on MPG: Prius Prime Plus in my hands | Page 18 | PriusChat
  • 23 mph -> 113.4 MPG - 32.7 MPG
  • 29 mph -> 107.4 MPG - 37.7 MPG
  • 31 mph -> 104.6 MPG - 38.9 MPG
• Tested 30 mph with and without "CHARGE: Prius Prime Plus in my hands | Page 19 | PriusChat
  • 30 mph -> 107.1 MPG - 32.4 MPG

The practice test driving at 30 mph suggests (37.7 - 32.4) / 37.7 ~= 14% loss of predicted MPG. Comparing the efficiency of "CHARGE" mode when parked versus 30 mph:

• parked -> 0.0094 gal / % SOC
• 30 mph -> 0.00727 gal / % SOC

There is an inconsistency that the predicted MPG using the parking rate, 37.7 MPG, was significantly better than the measured, 32.4 MPG. There has been speculation that under road load, the engine will operate at a higher efficiency point. But when calculated by itself, the 30 mph test revealed a significantly lower rate of gasoline burned per SOC%, 0.00727 gal / %SOC, versus the parked rate, 0.0094 gal / % SOC. I can not rule out a math mistake but these numbers are inconsistent.

What this means is I need to replicate both tests, in Standard day temperatures, scaled for a larger change in SOC. The 18 minute, parking test went to 16% and the 7 minute, 30 mph test went to 10%. But now I have enough data to estimate what it will take to reach a 50% SOC increase:

• Parked -> ~60 minutes
• 30 mph -> ~35 minutes, ~18 miles

Now this suggests a potential mechanism for the discrepancy, vehicle overhead and rate of charge. The parking test was just a single metric. In reality I should have measured the parked fuel burn and then enable "CHARGE" mode. Then calculate the effect of "CHARGE" mode on fuel burn. But now I know to run each for 60 minutes.

Bob Wilson