Prius Plug-in Hybrid Gets Improved 95 MPGe Rating

And that it doesn't offer the choice of when to deplete, unlike the production version.

.

 

Thanks, guys!

I had gotten rather discouraged yesterday, thinking that my new PiP's EV driving was likely to only get me 11 miles at 93MPG because of the 'blending' with gas rating.

The thing I look forward to most is taking short trips where I don't use any gas. It still looks like that will be possible, in addition to getting highly efficient highway speed driving on my way to work (where gas will be necessary).

 

I believe the differences of the test version compared to the real version were:
- Total usable capacity was greater
- Battery was made up of the original NiMH plus two Lithium subpacks
- Car always began in CD mode and user couldn't turn it off
- Once one lithium subpack was "fully" discharged regen couldn't charge it. (So, if both lithium subpacks were "fully" discharged the car was in CS mode until plugged in).

 

I don't believe that is correct, I am pretty sure there were reports regen was not artificially limited while capacity was available.

Note however that normal regen is part of CS operation, if regen puts the SoC above the sustained level it will be used primarily until the charge dips below the sustain level. You're not going to get new EV miles with normal stop and go regen (possibly could driving down a mountain or something (abnormally large regen)).

 

If his goal is to see if he can drive his commute in EV (what he said), then the ability to turn off the EV won't help him much.

 

That sounds right, although it won't be able to go back into ev mode for much, the new pack strategy allows for more regen energy.

Let me sumarize in order of importance

Key improvements of production over demo prius phv

1) Higher EV mode power - the numbers from Ken seem to indicate at least the Japanese version has 38KW from what we suspect was 31KW in the demo

2) EV/HV button - allows the driver to control engine firing. Those on the volt site seem to want this also, and it seemed like a major weakness of the demo with such a small pack.

3) Smaller lighter pack - There was a significant reduction in weight in size, so that the production version only displaces the spare tire instead of raising the floor of the hatch. It also dropped in hundreds of pounds of weight.

4) More regen - the use of a pack that can be recharged more and at higher power should provide the ability to use a higher percentage of regen energy. This is speculation, but may be the reason for increased mpg versus the demo vehicles.

5) Reduced cost of manufacture - The new battery pack is simpler with less cells and similar voltage to the regular liftback. This should allow fewer unique parts and a lower cost pack. Extra hardware for heating was also removed.

Negative changes from the demo
1) Removal of pre-heat - Toyota is no longer supplying hardware to allow for pre-heating of the car. This is partially offset by the ability to put the car in hv mode to use engine heat, but it will impact winter EV use and range.

2) Less powerful pack - 4.4KWh instead of 5.2KWh gives less range for charge depletion mode.

The production car is improved greatly from the demo. The negative changes seem entirely cost cutting tradeoffs. I doubt Toyota will do it, but it would be sweet if they offered a couple of upgrades. 1) a cold weather package that included a engine block heater and some form of pre-heat, 2) A extension battery pack, perhaps plugged in raising the floor of the cargo area - There are 4 modules in series, how about 3 more bringing it up to 7.7kwh this might bring the cd range up to 20miles.

 

That's why I'll be waiting patiently for your reports

 

I don't recall the demo units having heated seats. If true, that is a positive change mitigating need for the ICE heat in many cases. I would only use ICE heat on local trips for defrost. I see the heated seats as a partial mitigation of losing pre-heat, and I like the trade-off, I think.

 

Well reasoned. You'll enjoy the Plugin ability when you can and HOV every day and you'll be overall more efficient than a Volt (since you cannot plug in at work and are doing 90 miles). Always good to hear the discussion (and hopefully if my input) helped.. Despite what some here might thing, I'm not about the Volt, I'm about the right car for the right job. I did a lot of comparison and analysis and just like to share what i've learned.

Enjoy.. Your new Prius PHV.

 

One more thing -- I intend to keep tracking miles with Fuelly, same as before. I'd like to get 75 MPG. I think I can get that if I charge at work, especially since going out to lunch will be 100% EV. If I only charge at home, I'll be lucky to hit 60 MPG. But I'm only guessing. Maybe right before I get the car, I'll start a "Predict My Mileage" thread, with a valuable and prestigious prize.

 

Don't forget to track kWh consumed also. Hopefully Prius PHV tracks it for you.

 

If the PHV does not track it (and maybe even if it can)
can the Torque Prius extensions track kWh? I know it can measure battery stats so it could easily do net KW from that. Can it do regen?

 

That's an idea. The current gauges gets reset when you close the app. You can log it on SD card but it'll get big. There is a gauge that displays the value and also keeps track of min and max.

The author should be able to create a new type of display gauge that cumulate the total and saves the value when you quit the app.

 

Even if Ian does not support it, if you do your own plug-in you can do it yourself. (I'm working on my own volt app -- still a long long way from all the PIDs you did for the Prius

 

I just requested a new gauge. I have not ventured into creating plugins. It is good to know that it could be done so one day I can give it a try.

 

The following data is straight from Electronic Code of Federal Regulations under 600.116.12.

14.90 miles under UDDS (City) cycle is equivalent to 10.43 miles under the entire 5 cycles. I believe the recent 11 EV miles is the 5 cycle equivalent so the city drive cycle should give 15 EV miles.

Table 3 of §600.116–12—Multi-Day Individual Utility Factors for Urban “City” Driving

	Column 1	Column 2	Column 3
0	Schedule range for UDDS phases	miles[/B] Equivalent 5-cycle distance	miles[/B] Cumulative UF
1	3.59 2.51 0.08
2	7.45 5.22 0.15
3	11.04 7.73 0.22
4	14.9 10.43 0.28
5	18.49 12.94 0.33
6	22.35 15.65 0.38
7	25.94 18.16 0.43
8	29.8 20.86 0.47
9	33.39 23.37 0.5
10	37.25 26.08 0.54
11	40.84 28.59 0.57
12	44.7 31.29 0.6
13	48.29 33.8 0.62
14	52.15 36.51 0.65

If you are wondering what's UDDS cycle is like, see the below graph. The total distance is 7.45 miles so Prius PHV can do that twice with a single charge. If that's your typical frequent trip in city traffic with many stop and go pattern, you'll get 15 EV miles.

Since the average speed is about 20 mph, 15 miles range would give you a 45 mins drive. That's about 22.5 mins drive each way.

 

On this fuel economy leader page, EPA shows Volt's composite MPGe breakdown. 58 MPGe city and 62 MPGe highway. That may help us crack this nut along with the E-CFR link I provided above.

 

Even more updated one (showing Prius c as well):

http://www.fueleconomy.gov/feg/topten.jsp

(click on first tab: EPA Rating - 2012)