Prius seldom runs on batteries alone?

Not in three mile trips from a cold start on snowy streets, seldom exceeding

28 mph and sometimes with chains, I bet.

The weather has cleared and I'm into the 40s again (three mile trips and all).

Mike

Reply to
Michael Pardee
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Short trips are the big killer (same as with conventional power trains). Cold weather means the warm-up time is extended, and short trips mean the driving is mainly in warm-up mode. The rule of thumb is that a cold engine will burn about twice the fuel of a warm one, and the Prius follows that pretty closely.

Mike

Reply to
Michael Pardee

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

Reply to
Michael Pardee

I put it in Park to prevent this happening.

Right. Too bad the driver can't control charging by gas motor and use of battery power, because the driver could predict this better than the Prius computer.

Reply to
Bill Tuthill

Do you own a Segway? They charge from 120V, I believe, and go about 20 miles per charge. You'd get wet in the rain.

Reply to
Bill Tuthill

What size tyres do you have mounted on that Prius, and what brand? And do they really still sell gasoline in the U.K. by the imperial gallon and not by the liter, or I suppose you would spell it litre or some modern French- or Continental-based measurement of volume?

Reply to
Bill Tuthill

" Did you actually READ all the responses, to your questions and the others you no doubt found when you no doubt Googled on the recent traffic in this NG, and THINK about them?"

YES I DID. I have googled, I have read; that's why I included the reference to coal powered electric plants. (Of course, being an old fart, I may have missed "IT".) What I concluded is that in other countries the EV switch is provided by Toyota. Why? Is it because using it will improve gas mileage?

I have noticed that the ICV in my Prius runs way more often than I expected, and for more than just recharging the batteries. The cute animation in the LCD display clearly shows that most of the time the ICV is powering the wheels, i.e., providing more power than the electric motor by itself can provide. I am suspicious that this is done so as to improve the Prius's "drivability" in the US; i.e., greater acceleration. Us Americans are accustomed to "tearing" away from the traffic light. While in other countries slower accelerating vehicles are more the norm. I have also noticed that when I take my foot off the gas after a stop the Prius 'creeps' just like a normal automatic transmission ICV only vehicle (something that a manual transmission driver does not need). Again, a feature to improve drivability at the expense of mileage.

Given that it is well known that jack-rabbit starts result in significantly lower gas mileage vs a more constant power curve, I would be willing to accept slower starts for more gas mileage. Ergo, my interest in an EV switch. It is also well known that an ICV engine runs much more efficiently at a specific RPM where it generates maximum torque per gallon of gas; so it would make sense to operate the ICV at that speed exclusively for recharging the batteries and never for pulling the vehicle. That is why railroads use diesel-electric engines as opposed to diesel only engines. (Why tractor trailers don't also do this is a mystery to me.) (Yes there is a point where the diesel engine generates electricity as fast as the electric drive wheels consume it and that point varies with each engine based upon its expected use.)

So back to my original question: Has anyone installed an EV switch and used it long enough (a year or more) and noticed a marked improvement in gas mileage (10% or more).

(Why 10%? Because that show much I improved my Bonneville's mileage simply by using my cruise control as much as possible to accelerate the vehicle and maintain a more constant speed than I myself could do on the highway.)

BTW; I am a Physicist by training. I am not interested in "Implications" I want facts!

-thank you

disturbances in

Reply to
R PRINCETON

A multipart question? Good. Ans: Prius OEM (see other thread on Prius tyres); Goodyear?; no; doesn't everyone?; historically yes.

FWIW, "litres/100Km" sounds daft. Many UKians still say "mpg".

Reply to
Andrew Stephenson

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.

Reply to
Andrew Stephenson

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.

Reply to
Tomes

As most have said, the battery has to be charged above a specific threshold for the ICE to turn off. I have found that you also need to be in cruise control. Normal driving with foot on the accelerator just doesn't produce electric-only operation except at very slow side-street speeds. I guess that's because the Prius computer doesn't trust human beings to drive at a single fixed speed. My favorite EV speed in cruise control is 34 MPH.

To make sure the battery is charged and ready for EV operation, you need to apply fairly heavy braking from freeway speed.. Just slowing down slowly doesn't charge up the battery very efficiently. Unfortunately this kind of driving is uncomfortable for passengers, so don't do it unless you're alone. Also, make sure you brake *before* you hit a curve or encounter cross traffic.

Reply to
Chuck Olson

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.

I'm thinking that I am remembering reading that Toyota is considering the ability to plug it in for the next version. Dunno if that would actually happen tho. Tomes

Reply to
Tomes

Doing this has not occurred to me - I will try this. I figure that I don't need to have the engine running when I am stopped, even if it thinks that it needs to heat something up. It can wait to do that until I acceletate and co-use that power.

This is what I am thinking, I just don't know if I am right. Tomes

Reply to
Tomes

We are weenies too. We get 44-49 depending on the trip type here in west central NJ. I also look forward to seeing what it will do in the summer months. Tomes

Reply to
Tomes

Doesn't the cruise control need to be reset when the speed drops below a certain MPH? It does on my Sienna and I believe I read that it does on the Prius too.

Ah - I found it: "Slowing down to less than 24 MPH (39 km/h) will cause the cruise-control "resume" memory to reset. So if you have to slow down or stop, you'll need to set the speed again." - From the Toyota Prius User Guide

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So how do you start and accelerate in cruise control in the Prius? What is the trick?

Also, I have found that normal operation in my Prius keeps the battery charge near the top of the blue range and often in the green range. There is no need to perform abnormal braking stunts to ensure adequate battery charge. Tomes

Reply to
Tomes

Can't answer the "how to start in cruise" part: never tried. If you think about it, start and/or accelerate are not big parts of cruising.

Changing cruise speed I do by the book: flip cruise lever up (+1 mph) or down (-1 mph).

Reply to
Andrew Stephenson

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

Reply to
You guess

That's just it, I don't think you can. I do see this as a Toyota flaw. In my Jeep it remembers what the cruise was set at so after paying a toll you can just go back to the former speed without needing to find it again. Since that one is a 5-speed, I cannot try to have it go from the startup.

And, yep, changing the cruise speed is just as you note. Tomes

Reply to
Tomes

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.

Reply to
Hachiroku

You believe in myths or is it perpetual motion?

Reply to
who

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