First of all the work was done doing squats by the weight lifted. You didn't recover any work by squating.So you have to add the work done each rise to determine the work.

 

You're the alone one. Who else remotely agrees with you?

Why are you accusing me of name calling? Do you know what a troll is? A troll is someone who hijacks a thread, acts immature on purpose to start drama for their own amusement. I'm not calling you those dolls with the colored hair.

The point I was making you cannot only look at an A to B problem. it matters HOW the car gets from A to B. Your entire argument is based on "moving a car from A to B consumes the same energy regardless of how it got there", which is never true.

Driving fifth gear is more efficient than driving 1st gear. Did you know driving in neutral is mathematically driving in an "infinite" gear ratio? P&G is an extreme exaggerated version of driving in overdrive (fifth gear).

Driving in 2nd gear is more efficient than driving in 1st gear
Driving in 3nd gear is more efficient than driving in 2nd gear
Driving in 4th gear is more efficient than driving in 3rd gear
Driving in 5th gear is more efficient than driving in 4th gear
Driving in Neutral is more efficient than driving in 5th gear

 

The times used were averaged actual measurements.
Better still, how do you explain Dale Earnhardt winning Michigan by P&Ging to extend his gas mileage as clearly shown on camera.

 

I know you're on my side, but that's incorrect.

think of this. You spend a lot of work to build a lego castle. Then your baby cousin destroys it, and now all that work is nothing.

It also depends what "Work" you're talking about. In my lego problem, there's work in the castle, work by you, and work by the baby.

The same is ture for the car. He is talking about the work of the car, which is equivalent to the work of the lego blocks, which as you can tell from my analogy, does not measure how much energy was used to fuel it. That's why I said you cannot use work to measure fuel consumpion.

 

Sorry but work cannot be removed. As you pointed out all 3 instances involved work.
And as for the squats actualy work is done both to lift the weight and to stop it coming down. Neither cancels the other, Its additive.

Work is representative of energy when two cases of work over the same period are compared. Somwhere the energy must suppled to perform the work. When work is performed in a specific time as was in the model ( 34.5 seconds) thats power and power is absolutely fuel consumption. When there is no difference in time the work is also represntative of power and thus mpg required. The comparison is straightforward.

If you want to know the hp required take the work and divide by the time to get work per second and divide that by 550..
If one was about 200,000 lbft and the other 120000 lbft the horse power required would be 200,000(1/34.5)(1/550) or 10.5 hp and the other 120000(1/34.5) (1/550) or 6.32 hp. However for the acceleration portion only the power required was 120,000(1/4.5)((1/55) or 48.4 hp. Only by doing no work on the coast down do you gain the advantage.

PS note Dale Earnhardt Jr won MI today using P&G as was clearly shown him doing on camera.

 

Just do what Dale Earnhardt Jr did to win the MI400. For 2 laps he P&Ged to extend his virtually empty fuel enough to win. His actions were clearly shown on camera.

 

Because he did not show his SG data...lol

Your last calc did not appear to show the times I gave Friday. It looked like your original guesstimates???

I re-read the link at #8 and the Gas Geo and a few items on there sure jumped out. Go back and look.

did not see the tail wind mentioned in the rest of the testing. hmmmm
Anyone that has a SG knows it's impossible to read the instantaneous MPG reading. At best it's +/-5mpg steady state.
16 sec to get back to speed is way slow acceleration. Slower accelertion will leave the eng ECU in closed loop and greatly increase the efficiency anbd make the results better. If you look at the extremes of P&G the slow the acceleration the better the results will be IMHO.
huuu

If he had just used the current avg and cleared it at the start, he could of read the results. His claim was 8%.

manout
Do you know how to use the current and clear on your SG? If not and you do some testing let me know. I have used it many times and can help out on that.

Of course all of this is academic for this reason:
That was the reason I tried it 3 months ago and reported that in my SG topic. It's one heck of a work out. Couple that with the extra abuse of the car over steady state and for me it was a no brainier.

 

Work doesn't measure fuel consumption. Whatever example I have been trying to portray, that was my point.

Gasoline powers the engine, not the car. The engine in turn powers the tranny. The tranny powers the car's wheels. The wheels turn to move the car.

There are many things that can change between the engine and the car's wheels. This is why you can't just say A to B always burns the same amount of fuel.

 

And that is the point. Going A to B by P&G is more efficient than steady state speed. Thus uses less fuel. Hence higher mpg.
(gasoline doesn't power an engine either; the combustion of gasoline powers an engine.)

 

And that is the point. Going A to B by P&G is more efficient than steady state speed. Thus uses less fuel. Hence higher mpg.
(gasoline doesn't power an engine either; the combustion of gasoline powers an engine.)

 

YES!!! I CAN GO 100 mph again! All I have to do is coast down to 40, then run up back to 100 mph! I'll be averaging 60 mph but getting better fuel economy! P&G WORKS, GUYS! YOU CAN RUN YOUR CAR TO 100 MPH NOW! All you gotta do is slow down to 40 mph once in awhile! Also, be sure to race carovettes (mispelled intentially) while testing it out!

 

The reason I did not use your data points is because they aren't for my car. My actual coast downs measured 29.94, 29.88, 30.18, and 30.02. I used 30 seconds cause it made the math easier. But still valid.
I couldn't get near your 38 second coast down. Possibly you have much narrower tires than I .
If I had used your numbers the advantage for P&G would have increased.

 

[quote=ToFit2Quit;340176]YES!!! I CAN GO 100 mph again! All I have to do is coast down to 40, then run up back to 100 mph! I'll be averaging 60 mph but getting better fuel economy! P&G WORKS, GUYS! YOU CAN RUN YOUR CAR TO 100 MPH NOW! All you gotta do is slow down to 40 mph once in awhile! Also, be sure to race carovettes (mispelled intentially) while testing it out!

THE FASTER YOU GO THE MORE FUEL YOU CONSUME.
And every time you get to 100 immediately coast down to 20 so you average 60 mph. Can I take videos in addition to the police?
Pushing air out of the way at 100 mph takes 8 times more power (and fuel) than it does at 50.

 

This would suggest that Pulse and Glide method can't result in better eco because the energy to get back up to speed will always be more than the energy saved coasting. That is the net energy will be more that just driving steady. This is based on sound physics. There is no such thing as free energy as this would sugest.


Today before the Monday to work crowd took up space on my route I ran my manual transmissioned CRX over a 15.72 mile course, twice. The first using P&G and the second a steady speed. No traffic was encountered. The CRX has a 4.88 final drive for performance so its mpg will not match typical CRX. It also decreases coast down times.

Trial 1: Sequentially accelerating to 60 mph in 5 seconds in third and shifting to neutral (engine at idle) to coast down to 40 mph; then re-engaging the engine & repeating the cycle continuously for the entire 15.7 miles.. Average speed 48.6 mph. CRX warmed by 5 mile warm up prior to the trial run.
Gas consumed: .499 gal by volume. 31.50 mpg

Trial2: Steady speed of between 45 and 49 mph for the entire 15.7 miles.
Gas consumed: .603 gal. by volume 26.067mpg.

Gasoline was metered from a large 2.5 liter buret with 1 mm valve. Gas from common source. Fill to the upper neck of the gas filler nozzle. To get accurate measurements the buret was weighed before and after metering the fuel refill. Volumes obtained by using fuel density of 0.82 (51.16 lb/cuft). Otherwise we'd never have gotten 3 place accuracy.
Since the runs were made at just before dawn there was little change in temperature at 71F. The P&G run was first to insure that the steady state run would be with fully warmed up engine so experiment would not be bias toward P&G.

We conclude that P&G can result in increased mpg but that the requirements to perform that procedure are way beyond any reasonable and competent person to perform without serious endangerment to themselves, others, and environment. Also iour conclusion does not apply to automatic transmissioned vehicles.
In short it is a waste of time if nothing else.

The closest approach that might be feasible would be coasting down hills but unless the coasting speed is very near the 'normal' speed it imposes definite endangerment for the same reasons. Another might be dropping the clutch for short distances where the coast down may be only a couple of mph before re-engaging the engine. That proposition is so intriguing we may take time to run that trial.

There is no free energy involved. Just a reduction in power required to cover a given distance using stored energy. Dale done good, he did. Never thought I'd ever say that about an Earnhart.
cheers.

 

"But Officer, P&G really works, you should try it some day! I'm just trying patriotic and save gas!"

Yeah, it is true that going to extreme speeds will cause a major drag on the car. I guess what it boils down to the speed ranges in which P&G is tested. So the the test was done between 40 mph and 60 mph, where drag is really low @ 40 mph, but drag is more at 60 mph than at 50 mph. So by reducing the drag once in awhile with the same energy, it's more fuel efficient... But if ranging speed from 60 to 100, it's not good as cruising at 80 mph? ...hmm...this can get really interesting...

Please do not test 100 mph ranges on public streets.

Hahaha, I didn't expect it either. And thanks for being responsible!

 

Nicely done! I'm impressed.

This is the crux of the discussion, as I see it. It's not so much a question of whether it works, but rather whether the risk/reward ratio is satisfactory.

I wouldn't go as far as to call it a waste of time however. You saw a 20.8% improvement in fuel economy! That's a big number. I have this idea in my head for super-short P&G; the same technique with 2MPH, maybe 5MPH, speed range, computer controlled so it doesn't make the driver crazy trying to do it. The gains should still be significant, if perhaps not quite as much as a longer P&G cycle. A smaller speed difference between the highest and lowest values should greatly reduce the impact on traffic flow, safety, and so on.

Thanks again for performing the test, and for sharing your results.

 

Nice job proving me wrong.

 

You weren't wrong you just had another model. If I had a dollar for every imperfect model Ive set up I'd be a millionaire. This just happened to be one we've had 15 years to work on. You have only a slight idea how much bench racing has been done on this subject. The debate was more fun than putting it to the test.

 

That's very generous of you sir.

BTW Do you have a scan gauge? If so, why didn't you use it to back up the method you used?

 

Don't have a scan gage because my most used cars for trips have the equivalent of a scan gage but both are automatics, which neutral is not a good choice I'm told. In fact having escaped beyond 70 my only manual is the 91 CRX siR, my favorite racecar. And thats the one we used to test.
I do use my mpg displays to monitor and provide input to get better mpg on the road. Its easy to get more than 30 mpg with either of them if you work at it.