Prius seldom runs on batteries alone?

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     snipped-for-privacy@access4less.net "R PRINCETON" writes:

I'm tempted to throw this out to anyone else in the Toyota NG who isn't thoroughly fed up with explaining the same notions over and over. But try this (with my own questions):

Don't know that term. "Internal Combustion [something]"? If you mean the petrol [US:gas] engine, you cannot rely on how often the mimic diagram shows it running, as a guide to relative energy o/p of it vs the electric generator/battery/motor side of things.
Please read this bit carefully and try to accept it: the Prius is set up to manage its own internal systems. The "EV" button seems to have been a marketing experiment, nothing more. As far as the NG can tell, it is fitted to EU/UK models and not to US ones. My experimental results, which you should have found if you Googled, show its range is functionally pathetic on the open road; it only serves any purpose where you want to discourage (NB, not prevent) the engine from firing up. It has no overall impact on the miles you get out of each gallon (except in a very marginal way, due to interference with the car's control system). It will not help in passing Go, nor will it collect for you $200.
The petrol engine and electric motor run separately, or together, according to whatever the car's control system thinks appropriate so don't try to mess with it. If you don't like this arrangement then lift the bonnet [US:hood] and put an axe through that large, shiny box above the electric motor/generator/planetarygear lump.

Then you are unusual. All the Physicists (and physicists) I have ever known have also been interested in the implications of data, especially those which _appear_ to be anomalous.

You're welcome. If nobody objects, I'm going off duty now.
--
Andrew Stephenson


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R: Polymer Science Engineer here. As a physicist, you might have run across situations where an answer comes through discussion, as well as through a straight answer. The discussion is what occurs here and this is the normal course of events in this Newsgroup. This is not a flaw, it is a feature.
Patience Grasshopper.
"R PRINCETON" writes:

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"We need more reliable, clear numbers" Andrew Stephenson
"I agree, we can wave our hands around and make points both ways, but without real comparative numbers (which I for one do not have) it is all just speculation." Tomes
So basically; No one has any experimental facts to support any conclusion, or theory.
"Polymer Science Engineer here. As a physicist, you might have run across situations where an answer comes through discussion, as well as through a straight answer. The discussion is what occurs here and this is the normal course of events in this Newsgroup. This is not a flaw, it is a feature." Patience Grasshopper
So, this group is just a bunch of old farts shooting the breeze.
For the record, the way I learned science; discussion, speculations, conjectures, 'shooting the breeze' are all excellent ways to think about nature, formulate theories and suggest experiments to test such theories. But as mentor of mine once said, physics is different from logic, mathematics, and theology, in that we run experiments.
Clearly no one has installed an EV button, and utililized it in a consistent fashion (for example turning it on when you anticipate driving for less than 2 miles) and measured the resulting mileage.
Finally, for what its worth to those of you looking for 'hard numbers'; our first tankfull resulted in 44mpg (US gallons, not imperial gallons, of 87 octane regular gasoline), in a mixed highway and city (red lights) commute across gentle small hills of 75 miles per day. I also read that the US EPA will relabel the Prius from 60 city 51 hwy to 44 hwy this coming summer.
thank you for your comments
-princeton
"R PRINCETON" writes:

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     snipped-for-privacy@access4less.net "R PRINCETON" writes:

Forgive my bluntness, Mister Physicist, but it seems called for. Either you've not actually been paying attention to what we have been posting, or you're an idiot, or some mixture of both. Data to hand indicate the third condition, plus ignorance and ego.
When are you going to catch on that the Prius "EV" mode does not allow one to use it as you describe? Yes, you could engage "EV" for (say) a series of very short trips. But sooner or later the car's control system would decide the big battery had discharged deeply enough to warrant flipping out of "EV" mode and firing up the petrol engine for a recharge. It does that whether you like it or not, to safeguard the battery (not to mention your ability to drive the car). The length of run just isn't worth it for an average user, the person for whom Toyota make this car. IOW, as you've been told, repeatedly: THE CAR IS IN CHARGE OF STUFF LIKE THAT -- NOT YOU.
If you don't like that you already know one solution. The other is: shun this current Prius generation entirely -- along with us farts here shooting the breeze. I especially like the last bit.
(Trolls. Bah. You just can't get classy/clever ones any more.)
--
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Sometimes. Other times we get experts weighing in as well. It is a sum of all of it.

Yep, looks like we are on the same page here. We have not run this particular test and we have not found it published either, so we are back to our discussion, speculations and conjectures. It is what we have at hand.

We get about the same MPG here between Flemington and Bound Brook NJ and around here. I read that the whole EPA mileage rating system is being revised to project more realistic numbers, rather than their pie-in-the-sky utopian figures that they have been putting out for years. Pegging the Prius at 44 highway is realistic from my experience. Tomes
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On Sat, 17 Feb 2007 20:33:21 +0000, R PRINCETON wrote:

This is exactly it. They use the Gas engine more in the US to provide the performance Americans expect.
The funny thing is, the average American Prius driver drives the damn car like a silver-haired Granny in the 1964 F-85 she bought brand new 43 years ago. So adding the EV mode would be a good idea on Toyota's part. In the week I drove one, I spent some time crawling from a start, and found it did NOTHING! I was getting better mileage with an AT Tercel. When I started driving it 'normal', the numbers didn't budge.
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If the traction battery has the charged potential to move the car 1000 ft it doesn't matter if it's at acceleration from a dead stop or dispersed for the next couple of miles. So, I agree with your experience 100%. I disagree with your one week assessment of mpg though, unless you filled the tank several times during that week.
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BTW, I'll be at Thorn's market today sometime around 1 pm. I'm easy to spot. I won't be wearing a winter coat ;)
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On Sun, 18 Feb 2007 07:59:03 -0500, mark_digital© wrote:

Whew...I was...it was colder today!
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On Sun, 18 Feb 2007 06:38:24 -0500, mark_digital© wrote:

I was reading it off the computer...
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Yes, and you've already said that that was on a pre-production model in 2000. The car has had numerous changes since then! I suggest that you try another week test drive in a current NHW20 Prius.
(There's also far better emissions controls (notorious for lowering fuel economy) since your AT Tercel... and I won't get into the apples and oranges of comparing a manual to an automatic CVT...)
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On Sun, 18 Feb 2007 09:53:52 -0800, snipped-for-privacy@kluge.net wrote:

It was an AT Tercel...
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I've looked into the EV switch (available aftermarket) so I can move the car from the curb into the driveway without the usual condensation of acids in the exhaust. People who have put the switch in say it doesn't affect fuel economy either way - it's just for suppressing the engine operation when it isn't wanted.
Mike
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On Sat, 17 Feb 2007 09:00:56 GMT, "R PRINCETON"

Ralph,
Stop and think about hybrids, what they are and how they work. Hybrids are nothing new, the railroads have been using them for since the 1940's. Almost all freight trains are pulled by diesel-electric locomotives. They use diesel-electric for one reason only. A pure diesel locomotive would require a clutch that you couldn't believe. It would have to slip for 10 minutes or more while the train was brought up to speed while transferring as much as 2,000 horse power to the traction wheels through a 50 speed transmission. The electrics take the place of this 40 foot diameter, electric fan cooled, multi-plate wet-clutch as well as the mechanical drive lines.
Your hybrid car is a political solution to a political problem. Your car has to haul around heavy batteries, a big generator to recharge the batteries and all the electronics needed to control the electric motor, the charge going into the batteries and monitoring the condition of the batteries. Plus it STILL has a gas IC engine and fuel tank to haul around.
All of the mechanical inefficiencies are still there to which we add the electrical inefficiencies (alternator-85% efficient, electric motor-80% efficient, control circuity-85% to 90% efficient, battery recharge-60% to 70%)
There is no way it can get the same over-all mileage and still have the same performance as a gasoline-only car.
If you want an electric car, fine---buy one. But just remember, there is a reason why the Baker Electrics and Stanley Steamers aren't sold any more.
Jack
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You are right about the way locomotives operate and why they are diesel-electric (as are many truly huge machines). But you are mistaken to call them hybrids - they have only one power source, the diesel engine. They just have electric transmissions.
Hybrids today get their main efficiency improvement from not using the engine as much to do ludicrously inefficient work. As the OP noted, the engine is still used at times that don't make a lot of sense. Blame that on the infancy of the technology.

Actually, it is an engineering solution to a fundamental conceptual problem. Even as a teenager learning about cars I was struck by the horrible inefficiencies of using large engines to put out negligible power for nearly the entire range of the car's operation. But it was the '60s and gas was cheap. When I first heard about hybrid power trains (around 20 years ago) I immediately recognized them as the solution to the century-old problem.

Ah - that's where you are 100% wrong. One of the central characteristics of hybridization is that the acceleration performance is independent of the power plant capacity, just as a conventional power train's performance is independent of fuel tank size. The engine can be off or just plain dead without affecting the immediate performance of a serial hybrid (none in production yet, sadly). A serial hybrid is essentially an electric car with a charging system on-board. Right now the technology exists to build a serial hybrid that will give the hottest conventional power trains a run for their money; a Tesla (http://tinyurl.com/n52mh ) with a small generator tucked somewhere would qualify. Honda (http://tinyurl.com/y96x8o ) and Toyota (http://tinyurl.com/2w379 ) have both demonstrated concept cars that clearly fall in the high performance range and deliver fuel economy in the miser range - 400 hp and an estimated 40 mpg for the parallel hybrid Honda and 400 hp and 32 mpg for the series-parallel hybrid Toyota. Honda engineers pointed out in the Popular Mechanics article back then that using electrics for torque provides off-the-line acceleration equivalent to a 600 hp conventional power train. Toyota simply mentions 0-60 mph in 4 seconds.
Mike
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On Sun, 18 Feb 2007 07:14:04 -0700, "Michael Pardee"

Okay if you don't want to call a diesel-electric locomotive a hybrid, that's fine with me. But you shouldn't call hybrid cars hybrids either. They get all of their energy from their IC engine also. The only difference is that hybrid cars also have a mechanical drive train along with their electrical one.

No, it uses the IC engine more. The IC engine powers the car at all times, even when it isn't running. If the IC engine isn't running, the car is using energy produced by the IC engine at some time in the past and stored in the batteries.

You're confusing acceleration performance with efficiency.

Mike, you can't ignore physics. It takes energy to accelerate mass. Increase the mass and you have to increase the energy input to maintain the same performance level. That's why all economy cars are small and light. More mass also equals higher rolling resistance which requires energy to overcome.
You can use a battery and electric motor to increase the acceleration performance of a car with a small IC engine but you will have to put back the energy you have used at sometime in the future. Each time you convert from one form of energy to another, you will have losses which can't be overcome. You start out with the chemical energy contained in a gallon of gas. Then you burn that gas to produce heat energy but you can't capture all of the heat. You convert that heat energy into mechanical energy with an IC engine which has internal friction losses. Both hybrids and conventional cars have these same losses. To this, a hybrid car adds changing that mechanical energy into electrical energy using an alternator, friction losses and heat losses. You use that electrical energy to recharge a battery converting electrical energy back into chemical energy with it's associated losses. Then, at some time in the future, you discharge that battery converting its chemical energy back into electrical energy with more losses and that electrical energy back into mechanical energy with even more losses.
There ain't no such thing as a free lunch. Perpitual motion is a thing of fiction. If you believe all of these conversion losses add up to an increase in efficiency then you might want to buy this ethanol plant I have for sale.
Don't get me wrong, I like ethanol. When its aged in charred oak barrels for 10 years or so and then mixed with a little water. But burn it for fuel....man, that's just plain wrong.
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On Sun, 18 Feb 2007 10:50:42 -0500, You guess

But you are neglecting the factors which make hybrids more efficient:
The electrical system provides a means of recovering kinetic energy during braking. The energy which would have gone into heating the brake rotors (and wearing out the pads) is converted to energy stored in the battery. Virtually all of the battery charge comes from this source. Even 50% efficiency in recovery of energy which would have been wasted is efficient.
The availability of energy stored in the battery means that the engine doesn't have to provide all the energy under conditions of maximum demand. This allows the engine power to be down rated and therefore run at more efficient (higher) power levels more of the time, e.g. cruising.
The availability of electric drive allows the engine to be shut down at times when it is least efficient, e.g. idle and low speed operation.
But don't try to factor all this together, just look at it as a black box. You put gas in and go farther and/or faster than in a comparable non-hybrid car. What more evidence do you want?

If it is in Scotland and they are aging it for at least 12 years, let me know.
You act like hybrids are hydrogen fuel cells. People are driving hybrids now and getting far better mileage than with conventional cars. It is a proven, practical technology. Using your reasoning, a Prius should be getting 16mpg and no one would be selling them, let alone buying them.

But they make it with corn. If they were making it with barley, you would have a point. ;-]
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     snipped-for-privacy@mindspring.com "Gordon McGrew" writes:

Most anti-hybrid kooks are narrowband thinkers. They don't like to see the world as a web of influences. A simple straight line is about as complex as they can handle. For example, your point about the regeneration system sparing the vehicle's brakes ought to suggest to them another indirect saving: less wear on brakes; longer intervals between replacements; less use of materials and energy in their manufacture/replacement; and lower bills. Yet I live in hope that it'll click for them, one day.
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"Gordon McGrew" writes:

The engine isn't subjected to the strains of differing torque. The motor handles that load quite nicely. Extra fuel usually needed (remember the accelerator pump?) when lightly stepping up the speed is nicely handled by the motor instead.
If someone wanted to get off the starting line as fast as I can they better re-do their fuel economy calculations and stop lying through the teeth about that one-time 36 mpg fillup. Man! You might think us hybrid owners just fell off the alien turnip truck. mark_
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wrote:

What I am pointing out is that efficiency has increased along with performance - that is a basic characteristic of hybrid cars. Your premise was that it couldn't be done.

If all we were doing was accelerating mass, there wouldn't be an issue. The fallacy is that it takes some specific energy to accomplish the movement of mass from one place to another, even if the height of the two points is the same. That is not true at all; the efficiency of that operation is always zero since the final potential energy is the same as the initial potential energy. The question is how much energy is going to be wasted in the losses.
For the sake of argument we can keep the frictional losses the same, in which case the question is in the efficiency of the motive source. That is where conventional power trains are so dismal, running at a tiny fraction of their full power output and suffering the staggering losses that go with it. Hybrids make their biggest gains by using the power plant more efficiently. Not that much more efficiently at this stage, but doubling the efficiency from dismal to lousy is no big trick. There is something very wrong with using a power train that is less efficient at 30 mph than at 60 mph.
The proof is in the actual performance - even hybrids such as the Prius typically double the fuel economy of equivalent conventional cars in town. On the highway, where the air resistance losses are dominant, the advantage is much lower.
Mike
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