Sitting at stop lights and MPG

The computer factors in sitting at red lights just fine. It's no different that other driving. The computer keeps track of the distance driven and the fuel burned, and does the math for you. The only weird thing with the display comes with the US version, which shows miles per gallon. If you manage to go for a five minute period without burning any fuel, the computer shows a blank bar, since dividing by zero would produce an error. It still calculates your overall mileage correctly.

Tom

 

B) <div class='quotetop'>QUOTE(cheminee @ Oct 8 2007, 01:59 PM) [snapback]522799[/snapback]</div>

The computer factors it all in, but the time you sit at red lights your're not going anywhere. So there's nothing to factor. Miles Per Gallon, but no miles.

And that's why the Prius has the advantage...because it doesn't burn gas sitting still, right?

Remember, the guy who's burning gas while sitting still gets less MPG.
Or does he?

Wrap you head around this......Ordinary car and a Prius with one gallon of gas. Each drives one mile and sits. Who gets better mileage?


.
Ordinary car w/ 1 gallon of gas--travels 1 mile and sits--runs out of gas= 1 mile per gallon.
Prius w/ 1 gallon of gas--travels 1 mile and sits........battery depleats...ICE recharges...etc...runs out of gas= 1 mile per gallon.

Didn't expect that did ya?

 

Trust me ... you look stupid driving it ... it just depends who is looking. Do you have those testicles that hang from the hitch as well? Those are really classy.

 

<div class='quotetop'>QUOTE(cheminee @ Oct 8 2007, 12:59 PM) [snapback]522799[/snapback]</div>

0MPH = 0MPG

 

troll's post deleted....please don't quote the trolls...don't feed them at all.

My POS lawnmower does all that too. But it's still a POS.
So, one has to ask, why are you here? Maybe you like the look of people in Prius'. Deep down inside, in places you don't like to talk about.

 

<div class='quotetop'>QUOTE(cheminee @ Oct 8 2007, 07:01 PM) [snapback]522825[/snapback]</div>

cheminee, I didn't mean to confuse you.....Of course, The Prius can sit still and not burn gas...And that's one of the many advantages it has. My point was, the advantage does have limitations. It just can't do it too long.

 

<div class='quotetop'>QUOTE(9G-man @ Oct 8 2007, 05:20 PM) [snapback]522808[/snapback]</div>

Except the Prius will run out of gas 30 hours later than the regular car. So what's your point?

 

<div class='quotetop'>QUOTE(cheminee @ Oct 8 2007, 07:01 PM) [snapback]522825[/snapback]</div>

I think maybe we don't understand what you are asking (I know I don't). Say you had a traditional car with an MPG meter. It reads 30 when you come to a stop light. The engine continues running. As time passes and the light stays red, you have not gone any additional miles, but you are using additional gas. Thus the MPG meter clicks slowly down as the denominator (gallons) gets bigger and bigger while the numerator (miles) does not change. OTOH, a car whose engine stops at the stop light will see not change in MPG until and unless the engine starts (to charge the battery, keep the engine warm, etc). So the Prius MPG calculator does not have to do anything special. It just keeps dividing miles travelled by gallons used whether you are on the highway or at a stoplight.

Another way to think of this is "The engine turning off at a stop light does not increase the MPG of a Prius. Rather the engine idling at a stop light decreases the MPG of a traditional car.

 

Sometimes after I fill up with petrol and my L/100km goes sky high while I sit with the system on and work out my fuel consumption it will go up to 99L/100km so it is possible for the computer to work out consumption while you sit still. I only need to drive a few kilometres and the fuel consumption comes back to normal because the amount of fuel used while sitting still is minimal but when calculated against 0 KM an eye dropper of fuel = infinite L/100km

 

[/b][/quote]


The OP is asking if the Prius computer is taking into account the abscence of the use of gas while sitting still, which has no impact on MPG. So, it's a moot question. I was being facetious, but correct.
The computer is always calculating every few moments, even when sitting still. Sitting still has no impact on MPG in the Prius*, It does in other cars.

*to a point, see above

 

<div class='quotetop'>QUOTE(9G-man @ Oct 8 2007, 05:20 PM) [snapback]522808[/snapback]</div>

Check your math. I think you'll find that it depends on how much gas was in the tank when you start the experiment. Assume a car with a 20 gal tank, and assume you get to use the full 11.9 gal Prius tank....

Miles per gallon = miles traveled divided by gallons used.

1 mile divided by 20 gallons = 0.050 mpg

1 mile divided by 11.9 gallons = 0.084 mpg

The Prius still wins by 0.034 mpg making it 68% better than the "ordinary car"

 

<div class='quotetop'>QUOTE(cheminee @ Oct 8 2007, 02:18 PM) [snapback]522807[/snapback]</div>

if i may be a teeny bit more technical, the gas mileage is calculated by the car's computer monitoring how much fuel is injected by the fuel injectors: duration and/or how often [rpm].

if the on-board computers shut down the internal combustion engine [ICE, as we call it here,] the fuel injectors aren't injecting at all, so the gasoline consumption during that "parked at a light" period is exactly = zero, and gets added into the overall total.

all non-hybrids burn gas when the engine's running, whether you're moving or stopped, and that's one reason that we waste so much gas in the USA... there are so many traffic jams and traffic lights where the car ain't moving, but the engine still is.

vote for roundabouts!


+af

 

<div class='quotetop'>QUOTE(cheminee @ Oct 9 2007, 01:49 AM) [snapback]523002[/snapback]</div>

It's very, very easy. The computer totals all of the fuel squirted through the injectors, and totals the number of miles driven, then divides the total miles by the total fuel. That's all there is to it. Don't make it harder than it is.

For instantaneous mileage, the computer totals over a very short period. For the five minute bars, the computer totals over five minutes. For the average mileage, the computer totals from the last reset.

Tom

 

<div class='quotetop'>QUOTE(Danny Hamilton @ Oct 8 2007, 09:55 PM) [snapback]522901[/snapback]</div>

Check your criticism. I stated one gallon for each car. Totally valid math.

Your example has variable and irrelevent fuel quantities for each car, making your example irrelevant also. The advantage was placed where you wanted it.

 

<div class='quotetop'>QUOTE(cheminee @ Oct 9 2007, 01:49 AM) [snapback]523002[/snapback]</div>

Nope, those two figures are totally different. 0 Mpg is just that. 0.
99.9 electric is infinite MPG and plays a huge role on overall MPG. That the Prius' ultimate advantage.

The only way to know that is to know how much gas the Prius would use if it was idling, and mutiply it by how much time you spent at red light not idling.
You are confusing the absence of fuel use with some sort of perceived fuel gain. It's like the old saying a Dollar saved is a Dollar earned. True, but not.
And the root of this whole thread is the root of why Detroit disregarded this car as a gimmick to begin with. And also not true.