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Urban Legend? 1

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msquared48

msquared48

Structural
Aug 7, 2007
14,745
We own a Prius (2007 model). It was rated at 50 mpg highway and 60 City when we purchased it. We have obtained 50+ highway, but less than 50 City for the last 20 months since we bought it.

We heard through a friend that some years back, there existed a special button on the dashboard of the Prius that enabled the driver to override the 15 mph setting to engage the engine, increasing it to 30 mph. It effectively lets you run on battery power only, up to 30 mph. That button is supposedly on Priuses outside of the United States. It is not on our Prius.

That being said, we heard that Chevron sued the Toyota Company to have this button excluded from all cars imported to the US. Supposedly, Chevron would lose a lot of revenue if this button was allowed. Toyota agreed and that's the reason for the button not being there. When we asked the Toyota mechanics about this, they were unaware of the button.

To me, it makes sense considering the difference in EPA rated City mileage as compared to what we are actually seeing. I estimate our City mileage is 45 to 50 MPG where it is advertized at 60. I am aware of all the nuances affecting gas mileage. We are currrently averaging 50.1 mpg overall combined.

Can anyone confirm or deny this? If the button does exist, short of buying a Prius from Europe, how can I get the button installed? Is this an Urban Legend? Thanks for your comments.

I am posting this in Pat's Pub and the Automotive Forums.

Mike McCann
MMC Engineering
 
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You'll find out much more about the EV button in Europe and find more people who have extensive first hand experience and knowledge of the Prius here...
 
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Thanks Dan:

I signed up two days ago and have been looking around the site.

Regarding the other comments - to each his own I guess...

Mike McCann
MMC Engineering
 
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Just supposition on the Prius, but I do know that some of the really old cities in Europe have mandated electric only mode on public buses to reduce further damage to ~500 year old buildings from diesel exhuast. Volvo had a special bus model that was diesel/electric hybrid with a switch for electric only. Perhaps this is an extension of that?
 
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Apparently, from what I have found out so far from the forum above, the lack of the EV button in the States has to do with warranty issues. For some technical reason, if the EV buton is added here, it will void the warranty. I believe it has to do with either the inverter, the battery, or both.

That being said, I cannot equate that with the fact that the button is apparently not a warranty issue in either Europe and Japan. I am still researching.

Mike McCann
MMC Engineering
 
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I'm told epa requires 8 years warranty for the batteries (not sure why EPA cares). EPA doesn't regulate europe and asia.
 
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EPA cares because they don't want the landscape littered with toxic batteries that fail after two years...

Dan - Owner
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Here's a link to the Chevron issue - there are others. Not quite what I supposed, but in the ballpark.

priuschat.com/.../environmental-discussion/37480-what-really-holding-back-plug-hybrid-electric-vehicles.html

Mike McCann
MMC Engineering
 
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Ah Ovonics. One of my favorite companies. I'd forgotten the automotive NiMH patent stupidity, yes that justifies a certain amount of paranoia.


Cut and paste this into your browser address line


If you want the installation instructions

Cheers

Greg Locock

SIG:please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
 
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When I went through advanced hybrid diagnosis training we were told that the purpose of the "stealth" mode switch was because houses in japan are very close together, and are not insulated as well as most American homes, therefore the switch is used to keep ICE off when pulling out of your driveway so you don't wake up your neighbors. Not sure if that is 100% true or not but i can't see the switch making much of an improvement on gas milage. The battery power is not free energy, eventually the ICE will need to run to recharge the battery, using the same amount of fuel as the car would have used during slow acceleration with the engine running. That explanation makes sense, the US consumer would have no need for the stealth switch like a japanese consumer would, so Toyota saves a few bucks by not installing the switch.
 
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Also wanted to mention, I see about 5-10 Priuses a week. The average customer is getting about 45mpg. I do have one "hypermiler" customer getting 78mpg from his Prius, with no modifications.
 
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Right now we're getting 53, but it depends on so many factors... Highway-residential mix, gasoline additives, time of year, driver, hills, tire inflation... you name it.

We've had as little as 39 when we bought it 21 months ago when the computer was in the learning mode, and up to 60, briefly. Generally around 48 to 52.

I've given up on the button, as I can see the warranty issue, which I do not want to jeopardize, plus, as you say, the mileage savings issue really does not make sense energy-wise when you think about it.

Mike McCann
MMC Engineering
 
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