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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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The key to prius in town city mileage is to accelerate fairly quickly. Any time you take off it should be at around 1/2 to 3/4 throttle to quickly get up to speed and then drop to cruise. Also increase your stopping distance as much as practical to have more of your slowing from the regen system and less from brake friction. As for a button I can't imagine one. The current generation of the prius does not charge externally so you would have to run the engine to charge the batteries anyway.
 
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Many people who purchase hybrids fail to realize the claimed savings is in very low speed driving with a lot of sitting idle at lights. Gas guzzlers kill you if you're simply waiting for traffic ahead of you to move a car length every five minutes, and that's where the hybrids shine. Are you often doing 30-45 throughout the "city" with little waiting at lights?

Dan - Owner
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you're saying it makes sense that Chevron sued Toyota because their prius had gas mileage that was too good? Bulls*.
 
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Yes the paranoid part of the tale is pretty funny. As to the button, it doesn't exist so far as I can remember but if you have a read through


and ask if it hasn't come up. I think there is an aftermarket one called the coastal widget, or EV button

In particular Bob Wilson and hobbit and Graham actually know what they are talking about - there are some others as well.

The reason that T probably would not have fitted it is that they only use about 20% of the already tiny battery, in order to maximise its life. That button would take the battery out of the ideal 40-60% SoC range when it was used, very quickly.

Cheers

Greg Locock

SIG:please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
 
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There are a couple firms here in Socal that will convert your Prius to a 'plug in' (Google?) and, I suppose 15 to 30mph limit change is not all that out of the question. However, I agree with Greg as I just cannot see how this would be a practical solution for 'normal' use because of the very limited battery capacity.

My accountant had two Prius and neither ever got better than 45 mpg . He is now living in Hawaii and rides a bicycle!!!

Rod
 
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There is a button on non-USA prii that activates an "electric only/city mode"....this may be what you are after. BTW - the Prius is designed to override the EV-only instruction whenever the battery falls below 80% charge, at which point the gas engine will run to recharge it.




ISZ
 
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Thanks... I'll check out those websites. That is what I was looking for.

I see and understand some of the points made previously, but some still do not make sense to me energy-wise. I guess I'll just have to do more research.

Mike McCann
MMC Engineering
 
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I find all this talk about "high" fuel mileage cars funny. My 1996 dodge neon DOHC gets 40 to the gallon in the southern Oregon mountains and the only time I drop below 75-80 is if multiple slow cars are clogging up all three uphill lanes. (the emergency lane counts on steep grades as most trucks that drop under 35 mph use it to free up the right hand lane for trucks going near 55)
 
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An interesting entry into one of the blogs referred to above:

See:
Excerpt:
"Yes folks, as intimate as you might feel with your Prius, your high-tech friend is capable of doing things you never even imagined. With a little do-it-yourself, you can unlock a whole new set of latent magic powers that Toyota never wanted you to know about. The most notable thing your Prius is hiding from you is that it can run on pure EV mode, a feature that comes standard on Asian and European models, but is disengaged on those sent to the US. In "Stealth" mode, a Prius can go up to 34 mph on battery power alone. All the wiring is there--waiting to be hacked. A guide available here via CalCars shows a person how to hack the electronics and install a dashboard EV button using regular old RadioShack parts and household tools."

Posted by: mjbarbarino@yahoo.com on June 16, 2006 at 11:34 AM

> Very nice, but what does it actually *do*?

Thanks, and good question. (That 500-word limit is _harsh_.)

The short version is that pressing the EV button is a hint to the power plant that you'd really like to avoid running the gasoline engine (ICE) if at all possible.

There are a bunch of conditions where the car will refuse to go into electric-only mode (or will leave it if already there). These mostly have to do with protecting the battery, protecting the engine, or obeying some higher-priority pilot^H^H driver command.

The obvious/common ones are: battery state of charge too low, commanded speed over 34mph, and over-/under-temp readings on various important bits.

In general, the Prius knows better than you when to use or not use the ICE for best fuel economy. The EV button is for times when you want no ICE for reasons other than milage (like when you need no noise or no exhaust). It is also for times when you know something the car doesn't (like that you'll be parking in a couple minutes, or that there's a big downhill slope just ahead).

Indiscriminate use of "stealth" mode will reduce your gas milage and may shorten the battery lifetime. (However, Japanese and Euro Prii have this feature from the factory, so I suspect it isn't that big a risk.)

A bigger risk is that your dealer might hassle you over warranty service if they see you've hax0red your car. While the physical mod can be easily and invisibly reversed, it may leave evidence behind in data logs.

Disclaimer: Solely at your own risk, author accepts no responsibility, etc.

Posted by: dghenke on June 16, 2006 at 11:40 AM



Mike McCann
MMC Engineering
 
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macgyvers2000:

We average about half city and half highway driving, and being in the Seattle-Everett metro area, see a lot of hills. We live in a rural area, so we don't have as many stopl;ights as in downtown Seattle, but we have our share, with actually little time stopped for lights - one or two minutes at the most at a light. Some are timed too to help with traffic flow.

Also: carnage1...

Regarding stepping on the throttle to increase the mileage - the instantaneous mileage indicator on the panel went way down, and the engine kicked in from the start of the high rate of acceleration, so I do not see how any rapid acceleration saves on gas mileage with this vehicle. It seems contrary to everything I have heard before.

Mike McCann
MMC Engineering
 
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All vehicles are set up and calibrated to suit their intended markets. The setup is based on a combination of the lowest common denominator user and local prevailing legislation.

So there is always scope for "improving" a vehicle - undoing the work of the OEM. In the UK there are many firms who will "chip" a vehicle for you, basically remapping the ECU calibration for greater torque (at the expense of ???). Similarly, there are aftermarket firms who can "fix" the flatspot in a motorcycle's torque curve (the one put in there by the OEM to pass noise legs).

I'm not surprised that a Prius can have its factory settings undone/changed to suit a particular user. Maybe Toyota underestimated the intelligence of the average American customer and decided to think for them?

Stepping on the throttle to increase mileage: Forget the instantaneous mpg thingy. Gasoline engines are generally more efficient WOT. It's the sudden stopping (standing on the brakes) that's inefficient.


- Steve
 
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Interesting comment from the blog here:

"The most notable thing your Prius is hiding from you is that it can run on pure EV mode, a feature that comes standard on Asian and European models, but is disengaged on those sent to the US."

My question is WHY? It is not logical. I cannot believe it was to meet EPA emissions, so lets not go there... Regarding warranty issues, I can only assume that the Japanese and European versions have warranties too... Might be interesting to compare the warranties though.

Far more logical is $$$, whatever the reason. And if it is money - who makes it? "Follow the money."

Mike McCann
MMC Engineering
 
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who makes it, oh my, the oil companies. wow, the europeans and asians are lucky not to have oil companies.
 
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oh gosh, well that proves it for me. The US uses more oil than any other country. Toyota must have left the button off when they saw that graph. Seriously. Do you actually believe that nonsense? Can I sell you an antigravity machine or a fuel line magnet?
 
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Car companies are driven by market research. About 100 years ago they started learning that those who focused on making the best car went down to those who made cars the public wanted to buy.

They make what they think will sell best, but sometimes they get it wrong. Market research is not an exact science.

Japanese and European makers offer a very different model range and different features in individual models for the USA market vs all other markets. American makers have been much less inclined to do this and Euro makers somewhat less inclined to do it. I expect there is a direct correlation between attitudes to this and export market success.

I think it is very paranoid to accredit other reasons to the difference in the differences in features for different markets.

I fully support bot of ivymike's comments.

Also, whilst it might not be their first option, I think the power generation industry is a very good customer of big oil, and I expect big oil would want their share of any increase in fuel for power stations including extra power generation for plug in options for electric cars and they would be reluctant to undermine their relationship with the power generation industry.

Regards

eng-tips, by professional engineers for professional engineers
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Regarding Mike's link. Check out the per capita figures. Much more interesting.

- Steve
 
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The American market has always operated under the assumption that the American consumer is pretty dimwitted, and that they get "confused" with too many controls.

TTFN

FAQ731-376
 
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