Prius seldom runs on batteries alone?

Unbelievable! 11 answers and counting and no-one answers my original
question! Are you all a bunch of politicians!?!?!?!

OK, enough ranting....

Ignoring, increased wear and tear on the batteries or engine, total energy
equations involving my old coal powered power plant; and any disturbances in
subspace temporal harmonics....

DID THE EV only switch increase peoples mileage? and by how much?


thank you

-ralph

 

I considered listing each last tiny cause of inefficiency I could
imagine then decided to group them, eg: "* convert electricity to
form suitable for battery (low volt DC), then convert to chemical
energy, then back to electricity (huge losses overall)". Leaving
it to technically minded readers to fill in details seemed good.

We need more reliable, clear numbers.

 

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?

The implication was that it's not worth doing. The car is set
to care for itself and the battery. "Mileage" is another word
for "efficiency" in this context. Greater efficiency turns on
making better overall use of the fuel put into the tank. Read
my past posts on my EV experiments (see recent Google). EV is
purely there to solve local problems unrelated to efficiency.

GOT IT? Thank you. That ends this party political broadcast.

 

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

 

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

 

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

 

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.

 

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.

 

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?

 

" 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

 

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".

 

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.

 

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.

 

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.

 

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

 

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

 

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

 

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
http://john1701a.com/prius/documents/Prius_User-Guide.pdf

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

 

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).

 

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