REPORT: 115 Plug-in Priuses fail to crack 50 mpg average in year-long test

[DaveinOlyWA]

part of the test i am pretty sure was run in and around the downtown seattle area where the topography pretty much guarantees you are lucky to get 35-40 mph. its stoplights every block with 10-15º grades common.

havent read the data yet, but one thing we have to keep in mind, one company also had Pri's without plug-ins and fleet average was 38 mpg. so "under 50 mpg" as we all know is just under that figure because if it was significantly under, that figure would have been stated. so if getting say 48 mpg, that is still 30+% better than not plugging in which means someone (and why not just look at the several PC'ers here that have hymotion??) in normal driving conditions should be getting minimum 70 mpg which has pretty much already been verified with people who WANT plug-ins getting near the stated 100 mpg.

so putting any merit to this story is like telling someone here that they need to re-examine their driving style when they post here that they are getting 40 mpg

[bwilson4web]

Originally Posted by cwerdna

REPORT: 115 Plug-in Priuses fail to crack 50 mpg average in year-long test
I haven't had a chance to look at their data yet, but it sounds like the drivers need some Prius driving lessons.

There is a big difference in driving to stay within the plug-in, EV operating range and then driving in normal, USA gas-typical profiles. So I'm not surprised.

There are tricky aspects to 'plug-in' operation that remain open questions. More importantly, I think there is an interaction between:

• peak BSFC engine operation
• available electric power

That until these are integrated into a unified set of control laws, we're not going to see plug-ins in the hands of ordinary drivers achieve 'greatness.'

Bob Wilson

[drees]

This was posted on AutoblogGreen the other day. Here's my analysis which I posted there:

Here is some vital information for those who haven't read the PDFs. Fuel economy numbers reflect the 40-car fleet first and the 75-car fleet second. CD = Charge depleting, CS = Charge sustaining

1. CD trips: 62 mpg / 62 mpg
2. CD/CS trips: 49 mpg / 52 mpg
3. CS trips: 39 mpg / 43 mpg

25-30% of miles were in CD mode.
22-28% of miles were in CD/CS mode.
47% of miles were in CS mode.

Fuel consumption was about 34% lower in CD mode than CS mode.

Average distance between charges was 34 and 41 miles. Way too far for the size of the installed pack which will provide at most about 10 miles of "EV" miles.

So it's quite clear that the Hymotion pack met expectations once you look at all the numbers.

It's also quite clear that there is a lot of room for improvement in drivers training, pack sizing and charging opportunities.

[a priori]

I can see why Toyota wouldn't be too upset with these results if Toyota doesn't really want to go the way of the PHEV.

I think it would be a perfect solution for me, given my typical, daily use of a car.

Still, my lifetime mileage (for both the '07 and my new 2010) easily top 50 MPGs, regardless of season and even without a plug. Perhaps I'm better off just running quietly and merrily along in my regular ol' Prius?

[ewhanley]

Originally Posted by MSantos

I will kindly disagree.

In their typical "just drive it" attitude, they've trounced Honda and Toyota hybrids in the past as well.

Asking or expecting some people to leverage the inherent capabilities and fuel economy potential of a hybrid platform appears to be too tall an order, and in the end, mediocrity is the inevitable result.

Cheers;

MSantos

I second this. I think the biggest breakthrough in hybrid technology to come next will not be a plug in battery pack, but rather a software based way of increasing the mileage for average drivers. Most people do not care to learn the intricacies of driving to maximize mileage, and these test results and the real world mileage of many current Prius drivers reflect this.

Priuschatters, in general, are exceptional in that they tend to drive such that fuel efficiency is prioritized. I think the average driver simply gets in the car and drives without giving much thought to the effects of driving style on efficiency. The eco mode button in the 2010 is a good step in the direction towards mainstreaming hypermiling.

The next step will be to make eco mode the norm for the majority of drivers, and continue to incrementally ratchet down what is perceived as normal rates of acceleration and engine power. Some elements of hypermiling must be incorporated seamlessly into the operating system of the car in order for the majority of drivers to reap the benefits.

[TheForce]

I'm willing to bet over 90% of the non fleet plug-in owners are getting 100+MPG.

[daniel]

Even among Prius drivers, PriusChatters are a tiny minority. Most Prius drivers just drive the car as they would drive any other car. And with gas prices as cheap (yes!) as they are now, that's not going to change. Now, slap a $15/gallon tax on gas, and provide easy-to-understand instructions on hypermiling, and you'll see better numbers.

Note that Toyota itself went to great lengths to make the Prius feel to the driver just like an automatic-transmission car, even to programming in a slight creep when you take your foot off the pedal at a stop, and slight braking when you take your foot off the pedal while moving. There is no need for an electric or hybrid car to do this. On both of my electric cars, if I take my foot off the pedal, the motor is completely freewheeling: no braking, no power; it just coasts. Toyota wants people to drive the Prius as they would drive any other automatic car, and most people do just that!

You cannot expect car testers, whether EPA or CR to employ hypermiling techniques when testing Priuses, because any car will get better mileage when driven carefully.

[spwolf]

test is VERY useful to show driving habits of fleet drivers based on which car makers can create their future EV and PHEV vehicles.

For instance, average of between 34 and 41 miles between charges means that for fleet drivers, in the city, you would probably need at least what we consider now PHEV-60 or maybe even more to satisfy your average demand which is also shown by their average mpg of 38 when without electricity.

European cities are even worse with more stops and traffic lights, not even mention jams which Seattle is not famous for, and we have to wonder - what kind of PHEV would general public be ok with? PHEV-80 for Europe?

It would have been interesting to show mileage of 4cly Corolla in those same conditions and it would quite possibly be well under 30 mpg.

In any case, this kind of data is exactly what Toyota is looking at with its lease of Gen3 Priuses.

[DaveinOlyWA]

if we continue with the gas based transportation idea, the next big idea will not be a better car, it will be a better traffic flow design. granted, the hurdles are great, the expense massive, the task nearly insurmountable.

but we have the seeds already planted. a smart grid that basically removes nearly all traffic lights and controls the movement of every car on the grid. the driver would only be present for manual and unplanned course changes.

right now, the biggest impediment to gas mileage is 3 things... topography, driver skill and traffic control (or the lack of). the results of hypermile challenges especially when people are getting 80 mpg in a regular, non-hybrid, non plug-in car should tell us that its not the car that needs work.

so controls that makes the average driver more efficient is not going to happen, so the answer is software that takes the driver out of the equation is where we need to go.

now that will take time (im guessing about 3-4 years for the technology, 15-25 years for the infrastructure and the 12th of never for consensus to pay for it) time we most likely dont have.

[robbyr2]

The observation about driving styles is on target. I might have not been sufficiently clear, but that was my point- if you're driving someone else's car/truck and they're paying for the fuel, you probably won't be hypermiling.
If you're cheap, or were trained to drive by the Depression generation like me, you're going to exceed EPA estimates much of the time (at least the new ones). I think I would be able to exceed the results posted in a PHEV because of the way I drive my vehicles. I don't do jack-rabbit starts because I don't want to. I don't do more than 5-7 miles per hour over whatever speed limit because I don't want to. I don't slam on my brakes unless it's a real emergency (my mechanic says I will probably get 160K from my 01 Blazer's brakes). The only adjustment I've had to make is the "glide" part, and only to the extent that the Prius requires so little foot pressure to maintain its speed and I average over 53 mpg.

When a PHEV Prius is available, I will be looking at it seriously. I think I will get well over 53 mpg because of the way I've been trained to drive, and because I hate to pay for gas.