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Could Toyota keep Prius hot?

13790 Views 44 Replies 21 Participants Last post by  RSnyder
Since the first 5, 10 and 15 minutes are crucial in the mpg count, Toyota could improve the heating time of engine, if that is the real case. I say that because when you drive the Prius for an hour and you turn the engine off and you turn if back on right after, the mpg count shows low mpg's again the first 5, 10 and 15 minutes again. Maybe the Prius has the faster cooling system of any car in the market and nobody knows about it.
Then, if it is true that the Prius works better when is hot, why Toyota cool it down that fast, limiting the Prius's usage for long trips. There are a lot people in US and the WORLD that stop and go many times as a part of working and/or shopping manuvers in the city where Toyota claims to have better mpg and where the contamination is grater. I hope Toyota redifine this part of the design in the next 2006 version.
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Where do we start, folks?

Do your homework and you'll discover things like the thermos bottle which rewarms the motor quickly, even after hours or days. Just don't confuse the thermos with your flask.

It looks that those thermos are not that efficient because the recount is right back there after just one minute of engine restarting. It looks to me also that you did your homework, but unfortunaly wrong.....Do it again..
the thermos is more efficient than say, no thermos.... :roll:
I shudder to think how things look to you. But of course you know more than those fool Toyota engineers, so what am I thinking?
Why are you pinpointing the Prius then. Most other cars suffer the same thing it's just that it doesn't tell you on some fancy screen.
yeah, we really gotta beat up Toyota here. Really, why *can't* they simply suspend the laws of physincs and thermal exchange? I mean we are paying $20-26k for this car after all. This car is supposed to be so high tech, and all they can't do any better than a thermos?

Yeah I know eh? What they need is a bigger thermos. Maybe put the engine in a totally enclosed chamber with 5 inch thick walls to retain heat.
Your lucky to get the thermos. I dont have one :(
Tideland Prius said:
Yeah I know eh? What they need is a bigger thermos. Maybe put the engine in a totally enclosed chamber with 5 inch thick walls to retain heat.

I want - in fact I demand - a coal burning furnace to keep the engine warm at all times. This must be incorporated in the 2006 version!
Actually most people - including our Mr. Troll here - forget that Toyota smartly designed the Prius not just to maximize fuel efficiency, but in fact to minimize emissions. The Prius is first and foremost a AT-PZEV and SULEV, and this is given priority over plain old mileage. How fast the engine cools down is not the question. The question is, how fast does the CAT cool down? If the cat is not at operating temps, emissions skyrocket. That is why the first two minutes of running after a cold start or restart, the engine pretty much labors to warm the cat up to temp. This is obviously done at a sacrifice to initial fuel economy, but done specifically to reduce emissions.
Kudos to Toyota for a job well done!
Perfect Description

Perfect Description. Well done. Thanks. Now I have a perfect understanding of the readings within the first 15 miles of driving.

Now could you explain how come I got the same readings when turn off the engine and turn it back on immediately. "Again, within the first 15 minutes of driving the comsuption is no more than 25 mpg.

Like I said: How you keep the Prius hot?

Or maybe there is another reazon totaly different than we have been talking here. Maybe the problem is somewhere else beside of what your perfectly explained.
Perhaps the cat-con is heated on a timer, with no thermostat feed back. So everytime you start it, the car heats it for 12 minutes no matter how long it was off :?:
Gee, I find if I am running errands and the car is off for less than about 20 minutes it behaves as if it was still warm. Only if I'm gone for a while does the engine cool down.

Perhaps trolls live in very cold places.
Actually I have found MPG for the first 5 minutes after filling up with fuel quite close to what I would get before I stopped and powered off for gas.

Well, I do have it in ACC to listen to the radio, but for safety, I do not have it in READY.

Even for that 5-10 minutes though, the CAT can cool a bit, requiring some warmup, but not nearly as much as if I started cold.
There was a couple of real warm days a week or so ago and my mileage went up. I hit 60 mpg for a day or two. There were some other factors too, but since then the weather has been back to the 40's in the morning.

Same old story.
This must be a troll. Not only is my mileage affected very little if at all by a short off cycle, but even after a weekend on no driving, my second five minutes is often at 99.9 MPG or 75 MPG. Only the first 3-4 minutes are affected by the warm-up, although it shows up as the first five minutes due to the nature of the display. I get low mileage for the first fifteen minutes only when travelling uphill for the first fifteen minutes.

By the way, four of my last five tanks have been at or near 650 miles at an average consumption of 58 MPG. My wife just finished her first tank on her new 2005 model at 51.4 MPG and 564 miles on the tank but she drives too fast and rarely pays attention to mileage.

We have been banging the expeculations here.

Hitting the shadows of the darkness.

Is there a heat loss in the form of gases that get released thru a valve that was wrongly / correctly programmed?

Turning on the car from cold and turning it on again and again maybe represents no different to one of the several computers that control the Prius, like a routine or macro that runs anytime even different situations?

is it a hazard to keep those gases encapsulated in a crash situation?

or maybe, gases, liquids, etc. got nothing to do with this....!!!

or Toyota will have the solution in reserve for the 2006 w/75mpg?

Why Toyota does not come and respond to give us some light?
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gee maybe its just your car. i find that my car has to sit at least an hour if not more before its mileage in the first 5 minutes is back down to a cold start level.

then again. it must be those macros you talk about that ignore engine function, temperature, mixture and everything else... only paying attention to how long the car has been on...yep that must be it...
(cue Twilight Zone theme music)
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