2005 Prius

Good point, but at least nobody has figured out how to charge us for the oxygen (so far).

Merritt

Of course...you're absolutely right...BUT that wasn't the thrust of the argument was it? :)

But do you need $10 to make it up the hill, or can you do it on $3?

I may prefer a Hummer, but a Prius could do it far cheaper.

Mack

: OK, but the Prius suffers from all these loses too plus the additional : electrical/chemical ones.

Actually, the losses are far less than were it totally a gas engine. The gas side is out of the picture if the less-loss electrical motor is powering the car. Greater torque and efficiency is gained from the pair in unison since the inherent loss of the gas engine is coupled with the not as great loss of the electric motor added to the output power. That is why Toyota can achieve times almost equal to that of the Camry, although the Prius has the smaller engine with lower net loss.

In short, better efficiency equals better fuel mileage with almost equal performance. Not to mention any small gains (I.a. "free fuel") made from regenerative braking that you do not receive from the gas-only vehicle which is otherwise lost.

Mack

Thanks, Mack, for the injection of lucidity into the discussion. I thought I'd just add that this engine uses the Atkinson-Miller Cycle

Have you driven one? I always left the monitor so that it showed where the power was coming from, and going up that hill it would use both motors. Going down the hill in "B" would regenerate and recharge the batteries.

So, not ALL the power stored in the batteries comes from the gas engine. This is also shown on the monitor.

In fact, in the brief time I drove one, I actually managed to generate enough electricity to fully charge the batteries and more.

Exactly, that is what I meant by improving efficiency. But, in a car like the Prius, it is still a matter of improving the efficiency with which you use gasoline, even if the wheels are driven by electricity.

Merritt

But the losses are not additive, and overall the hybrid scheme has less loss (more efficiency) than a pure ICE automobile.

Merritt

Say, Chuck, why not keep the lucidity streak going by pointing out that Atkinson-Miller Cycle ICEs don't need a hybrid sticker to work. They have and do work in non-hybrid vehicles too. In fact, since all the vehicles we're discussing require 'rotational power', why not use Atkinson-Miller Cycle ICEs everywhere?

Actually, the losses aren't far less but are somewhat less under a strict, limited set of circumstances (certain types of city driving). Torque is purely additive. The two together or separately doesn't make any difference.

If we're still talking about the 4 cylinder Camry, performance is somewhat equal only until the Prius batteries are exhausted which happens quickly. After that, there's an extended period when Prius performance lags because the ICE engine must power the car and charge the batteries. As long as the Camry doesn't run out of gasoline, it has no such limitation, therefore, the two really aren't comparable. It's been pointed out before that the "free fuel" downhill power was paid for, in gasoline, when climbing the hill.

Look Hachi...let's get down to basics here...let's start out with dead drive batteries and an empty gas tank...

Not much happenin' right?...

Still nothin happening, right?...hummm...we fool around with switches and move every bloody control (except the engine starter) we can find...nuttin' right?...

Now then...this ain't right productive issit?.

Well, let's dump one gallon of gas into her, and start up the gas engine...woohoo...here we go...we drive for awhile till we use all the gas up and the gas engine dies then we use the batteries till they go dead...now we've moved maybe 55 miles...hasn't those

The above of course ignores the fact that you likely cannot kill the drive batteries (nor start out with dead batteries either), but that's just a practical limitation, doesn't affect the example.

ALL of the distance travelled comes from the gasoline. whether directly or indirectly doesn't matter, it all comes from the gasoline in the long run.

How about a practical example:

Suppose you have a Camry (make it an economical 4 banger) and a Prius sitting in your driveway. You need to drive 800 miles to a job per your boss.

Which do you choose and why - assuming your boss gave you $200 for the entire trip to spend?

Just an efficiency/curiosity exam............ ;o)

B~

But this still doesn't take into account any regeneration from braking or rolling down hills! When I was driving one, I got the batteries topped up quite a bit just by braking and rolling down hills. I also managed to 'fool' the car into staying on the batteries more than the gas engine. So, quite often, esp when going downhill, the gas engine was OFF and the batteries were CHARGING. Where I was driving the thing, if I took one route I was going downhill more often, and a different route home did the same thing. I was actually OFF the gas engine quite a bit.

Yes, Logic would say all the mileage comes from gas, but practice is quite different.

But, think about it a minute...the energy that you -recaptured- by braking was paid for with gas (the car didn't just suddenly

-get- that speed)

Yes, BUT you have to average out the up hill and down hill because, in the long run, for EVERY UPHILL there's an equal DOWNHILL and, if you ended up in the same place, then it wouldn't MATTER what ROUTES you took, you HAD TO climb just as many feet of elevation as you descended didn't you? :)

I beg to differ Hachi...it's all from gas but it IS more efficient...

Think about this...there's NO OTHER SOURCE of energy than the gasoline, so where's the extra energy coming from? These cars just USE the gasoline more efficiently...regular cars lose energy when they brake (the energy turns to heat and is lost) while hybrids return some of that energy to the batteries.

There's a phrase for machines that deliver more than you put in and it's not Toyota Prius.

Yes, I guess I did. But one was a steep downhill, the other was a long, gradual uphill. So I would take the steep one TO work and the more level one home. THe thing was, the long gradual way home actually brought you higher than when you started so you were going downhill at the end, and i was on the batteries quite a lot.

Gee, same analogy could be said if you were to switch gas for battery. Dump all the gas out. Charge the battery and go. Did you need gas?

Most all would agree the hybrid is more efficient in use of gasoline than the older ICE though. If I am paying out of my wallet, the hybrid will win for vehicle of choice with regards to less fuel consumed compared to the ICE vehicle.

Now if I want to be a pig, I'll go borrow the neighbor's Hummer and give him a couple of bucks for gas. :p

B~

Right. The gasoline engine is powering the car and charging the batteries (which are also powering the car).

So where is it coming from?

Believe me, ALL the power stored in the batteries (beyond their initial charge when installed) comes from either the gasoline engine, or the potential energy created when the gasoline engine drove you up a hill.

Of course, why not? But you are burning gasoline to do it. YOU CAN NOT GET MORE ENERGY OUT THAN YOU PUT IN, AND THE ONLY THING YOU PUT IN IS GASOLINE (AND OXYGEN FROM THE AIR).

Merritt