Plug In Prius - Seattle Times Article

[drees]

AutoblogGreen
post on the article. Lots of misconceptions in the comments, feel free to help correct them!

Disappointing results - just 51 mpg - for converted PHEV Priuses in Seattle - AutoblogGreen

[spwolf]

man,i cant wait to see what happens when Volt comes in.... Take these reports and multiply them by factor of 100 as Volt will get mpg in 30's when out of electricity.

Oh I am sure few will give benefit of the doubt as it is AMERICAN, but that will last for few weeks at most :-).

I just read on Autoblog green about Fisker sports car with similar system to Volt, and OMG what a failure will that be.... 50 miles of EV in Perfect driving conditions, for a sports car... that means people will get 10-15 miles when ripping it and rest of their trip will be spent on 4cly engine... in +100k car... ooops.

[Fibb222]

Tip of the hat to miscrms for the great comments and analysis. Well done.

[Aces]

There's another consideration too. I live N. of Seattle, & work S. of it. My wife works in downtown, near where City of Seattle's main office builing is. I hate picking my wife up, because of the hills. They are steep, with short lengths between lights. If these cars are driven mostly to/from the parking garage there @ 6th & Columbia, these hills, combined with short trips (W/o use of EBH) would explain a lot. What's really lacking here is comparison with regular prius driving. And to really test it, they should track drivers to trip milage, then compare when a specific driver uses a regular prius vs a Plug-in one.

[Unlimited_MPG]

They just put this on the local news here in Seattle also tonight. Here is the news from their website.

City testing fleet of hybrid cars | Environment News | KING5.com | News for Seattle, Washington

City testing fleet of hybrid cars

05:57 PM PST on Wednesday, February 25, 2009


By DEBORAH FELDMAN / KING 5 News

SEATTLE - A fleet of modified Prius cars is now rolling across King County as part of a test program to see how well electric vehicles can handle local streets.
It was expected that the cars would deliver more than 100 miles per gallon, thanks to a large battery that can be charged with an outlet. However, driving the vehicles around Seattle is serving as a reality check for some very interesting reasons.
When Rich Feldman drives around town in the hybrid -- he's pulling double duty. Not only is the car getting him to his destination as a city of Seattle employee, it's also helping collect data about the true efficiency of a Prius that also doubles as a plug-in car.
"It's great. Just knowing that you're kind of driving the future," he said.
It's one of 13 Prius cars being used in Seattle and King County with a 140-pound battery in the trunk.
"This is straight out of the labs from MIT. Lithium nanofosphate," Feldman said.
The cars are tracked by computers to see exactly how much fuel is being used.
The bumper boasts these cars can get 100-plus miles per gallon, but so far they're averaging just over half of that.
There are several factors that can put a real drain on the plug-in's efficiency, including cold weather, hilly terrain and aggressive driving.
The electric charge only lasts 30 miles before reverting back to regular hybrid mode.
It takes anywhere from four to six hours for a car like this to fully re-charge. So for someone who's using it just for a commute to and from work, they'll be able to have the car completely re-charged in between those two drives.
Seattle City Light employees are driving three of the test vehicles. They say when you couple their hydroelectric power grid with the plug-in car, a completely green drive is possible.
"From generation of the electricity to produce this, up until the point where that hybrid engine kicks into combustion operation, you are not putting any greenhouse gasses into the environment," Scott Thomsen said.

[Unlimited_MPG]

Just watched the news article on tv and the guy from Seattle City Light said he was able to achieve the 100 mpg. "With careful driving he often hits the average of 100 mpg and others can too."

[bwilson4web]

I would recommend reading:

"PHEV Battery Requirements" by Rousseau, Pagerit, and Fellah, Argonnne Labs, Dec. 3, 2008

Their conclusions, pp. 18

• "Aggressive driving will put limits on all EV range, which in turn favors a blended mode operational strategy."
• Battery size is critical for the expected range
• Aggressive driving results in larger energy requirements

What this means is a PHEV probably won't work in fleet usage where the daily utilization is much greater than just commuting. For commuters, it can be wonderful, but if tried with a taxi cab, the results would be humbling ... there is no free lunch but you can sometimes get a great appitizer.

Bob Wilson

[chogan2]

Originally Posted by bwilson4web

I would recommend reading:

"PHEV Battery Requirements" by Rousseau, Pagerit, and Fellah, Argonnne Labs, Dec. 3, 2008

Their conclusions, pp. 18

• "Aggressive driving will put limits on all EV range, which in turn favors a blended mode operational strategy."
• Battery size is critical for the expected range
• Aggressive driving results in larger energy requirements

What this means is a PHEV probably won't work in fleet usage where the daily utilization is much greater than just commuting. For commuters, it can be wonderful, but if tried with a taxi cab, the results would be humbling ... there is no free lunch but you can sometimes get a great appitizer.

Bob Wilson

Bob,

I'd like to expand on that "aggressive driving" comment because it is easy to understand why that matters a lot more for gas use in a plugin than it does for gas use in a regular hybrid.

With a plugin Prius, the share of propulsion energy that comes out of the gasoline is determined by how heavily you use the throttle. Anything up to (maybe) 40 horspower load can be handled by the electrical side alone. Everything over 40 HP load has to be handled by the gas engine. So, until the battery depletes, the mix of electricity and gas used to propel the car is determined (largely) by the fraction of the total power demand that occurs above and below that 40 HP (or so) threshold.

So a lead foot not only increases total energy use, in this case, it radically shifts the mix from electric to gas. The "gas mileage" of a plugin is much more leveraged with respect to average power demand than is the gas mileage of a regular hybrid.

The car imposes some other limits on minimum gas use (e.g., idles the engine over 41 MPH in all circumstances, when you need cabin heat, etc.) But that's the gist of it. I wouldn't even say that the lightest possible accelerator use results in minimum total energy expenditure, but I'm pretty sure it maximizes the fraction of propulsion energy drawn from the battery and minimizes the fraction drawn from gasoline.

[DaveinOlyWA]

ya saw same shows online and on TV and one is much more realistic in admitting that some of the fleet duty cars which NEVER see opportunity charging will only get incremental mileage boosts (Seattle is like San Francisco or any other West Coast Pacific town in that its nothing but hills) but remember "just over 50 mpg" is still more than a 25% improvement over regular Pri's due to the severe driving conditions.

now, take away the "duty" part of the drive, make it just a commuter car, and BOOM, now we are seeing 100 mpg and there are people in the study who are getting that. what the one article centers on is the WORST CASE results.

now create an environment that caters to EV's (iow, REQUIRE companies to provide a plug in option) and now we most likely see a fleet of cars that never burn gas during the weekly commute

no one said it was supposed to be easy, and if you look at the transition 100 years ago from horse to car, i think you will find that this transition is actually much easier

[bwilson4web]

I remember reading (in a HISTORY BOOK!) an article about how superior horse was because it does not get stuck in the mud with a photo of an early 1900s car stuck up to the axles. The moral of the story is that horses are better than cars. <grins>

Bob Wilson