dancodanco,

Have you ever towed a trailer before?? Joe has it right... Rpm/speed is always a constant, whether you are towing, coasting, cruising, WOT....

If I'm cruising down the road in direct drive (1:1) and going 60 mph I'm pulling around 2400 rpms.. This occurs whether I'm running empty or towing my #5000 TT... The difference is that I'm only getting 10 mpg towing and while I don't have any actual mpg figures when I'm empty, I'm sure I'm getting better then 10 mpg running empty in direct drive...

Throttle position is what determines how much fuel you use....

Take a perfectly level road and no wind (which NEVER occurs in the real world BTW..) If I'm cruising empty at 60 mph in OD, I'm pulling around 1500 rpms. The engine has no problem holding and maintaining this speed with an empty load and very little throttle position. Add my #5000 TT, I'm now having to haul a lot more weight, but I'm also fighting a lot more wind resistance too. If I'm going 60 mph in OD, the engine is still doing only 1500 rpms, BUT, I'm in the gas pedal a lot deeper because it has #5000 of extra weight that's also trying to plow thru the air!

What usually happens is that the TPS (Throttle Position Sensor) sees that I'm having to press the gas pedal deeper, so it'll downshift back into direct drive..

My ACTUAL EXPERIENCE with this is that I can get the truck to go into OD most times while towing, but then I find I have to press the gas pedal a lot deeper to maintain my speed when I'm towing... So, there is no savings in mpg at that point, because my engine is still only turning 1500 rpms, but I'm dumping a lot more fuel into the cylinders to make the torque to maintain that speed. And, my engines peak torque numbers come just above 2500 rpms...

When I'm in direct drive and pulling 2400 rpms going 60 mph, I'm only having to press the gas pedal a very little bit to maintain and even able to accelerate if needed while towing... Sure, my rpms are higher, but the engine is having an easier time with the extra load and wind resistance because it's running higher rpms, and more into it's peak power range...

I don't disagree that when you are running empty, you get better mpg's in OD compared to running in direct... That's a no brainer... That's why I don't have any actual mpg figures for running in direct when empty!

Add that #5000 'brick' behind you and all that changes.... Running in OD actually causes my engine to run hotter and my trans to run hotter.... That's because it's having to work HARDER in OD then in direct when it's under load....

Remember the old 10 speed bicycles?? What happened when you left the gear in 5th and tried to go from a start? What happened when you tried to go up a hill? What happened when you had your buddy sit on the handle bars?? You probably found that you needed to downshift the bike to a gear that allowed you to pedal more rpms, but you got moving a whole lot better, and kept your legs from burning, right??? Same principle with a vehicle....

Oh, you made me write a book here, so it's probably moot at this point.....

Do whatever you feel is right and report back to us when you have some "real world" experience with this....

Mitch

 

Mitch, Joe,


I think you guys are wasting your breath, so to speak... This guy doesn't understand, and likely never will... I bet he drives a Civic with a coffee can exhaust and an electric turbo... Probably a Tornado thrown in there somewhere, also...

 

Wow! for thoses who will not read carfullly and comprehend my preveoius post's. mitch and gijoe are backing up what i wrorte. the relation between load(L) road speed(V) rpm(R) and fuel usage(F). gear box's of 1x1, 1x2 etc.


on a side note if you cannot extrapolate information from availble information, you are as smart as a chimpanzee (monkey see, monkey do).

here is some more interesting info yes its a hybread car not f150 but its still powered by a gas internal combustion engine that turns a shaft into an xmisson that siwtches between wheels and a generator that chargers a battery that may turn the wheels. The mpg magic is in the transmission lets the engine operate at peak efficancy and reduces power loss.


TIP: Use full-throttle acceleration

Effort involved / impact on driver: Medium

You'll get the best efficiency around town by accelerating with full throttle, and shifting up to the next gear quickly, before engine RPMs rise too high.

There are two reason why this works. One is that the higher the gear, the lower the frictional losses. By getting to 5th quickly, the total number of engine revolutions is reduced, with a corresponding reduction in frictional losses. The second reason is pumping losses. This is the work done to force air past a partially closed throttle plate. The more closed the throttle is, the higher the losses. Accelerating quickly reduces throttle losses, because the throttle is open. In addition, engine speed is lower in fifth, so to generate the same amount of power, you have a larger throttle opening (and hence lower throttle losses) - this is another reason to get to higher gears as quickly as possible.

The best fuel economy is gained by a combination of the gas petal to the floor with shifts at as low an rpm as possible to sustain your desired acceleration. This ensures a fully open throttle during the entire acceleration event and gets you out of the lower gears as quickly as possible, for lower frictional losses. It also gives you even more electric motor assist, as the acceleration takes longer. There is only one problem with this technique - its virtually impossible to do. You have to shift like a race car driver, except that the shifts are at low rpm instead of high rpm. You wind up going through gears like a maniac. It can be a lot of fun, but you have to be really involved with driving (no cell phones) and the technique is extremely counterintuitive. The combination of mashing the accelerator and shifting at 2500 or 3000 rpm just doesn't feel right. However, if someone is willing to practice this, they can get a nice boost in FE around town.

After accelerating this way in 1st & 2nd gears, you'll often be up to your desired cruising speeds. Now it is time to switch modes, using as little energy as possible to maintain this speed. Typically you'll now want to be in fifth gear. The 1-2-5 shift pattern (or 1-2-4 as the case may be) may seem strange at first. After all, why are those other gears there if you shouldn't use them? The answer is to think of them as passing gears or cruising at slower speed gears. In most cases, this is the way I use the five gears:

1: Accelerating gear
2: Accelerating gear
3: Even slower cruising / quick passing gear
4: Slow cruising / slower passing gear
5: Cruising gear

 

I'm plenty calm. I've got much more important things in life to worry about than someone who refuses to face the facts.

I can comprehend what you wrote just fine. If I didn't understand what you wrote, I would not be able to point out the obvious errors in your reasoning.

98Lariet4x4, I think you're right... we're wasting our time. We, and the rest of the worldwide automotive industry are all wrong. The auto companies have absolutely no desire to develop a vehicle with a 1:7000 overdrive gear because it would get 376 miles to the gallon of gas while pulling a freight train.... We're suffering from some Koreshian malady called paradigm stuckness or we've got our heads in the sand because it's not like billions of dollars are spent every year in R&D trying to maximize fuel economy while not sacrificing performance.

When the rest of the natural world is wrong, you've gotta wonder....

And what the hell does anything to do with a hybrid have to do with motivating our 5000 lb truck down the road??? Completely different concept, completely different powertrain, completely different in every conceivable way. (Except for maybe the fact that they both use gas).

I know a simple way to get infinite fuel mileage: Run a hydrogen fuel cell. Keep a gallon can of gasoline in the trunk, and then you can claim you go infinity miles with a gallon of gas. It makes about as much sense!

 

You can extract information from a chart, but you cannot extrapolate the data and then call it real. Run a vehicle on a dyno and plot the HP/RPM graph. If the graph runs from 800RPM to 4500 RPM, you can extract the peak horsepower from that graph between 800 and 4500 RPMs. But you cannot extrapolate that data and say that you get any particular horsepower number at 6000 RPMs.

 

wow are you watching me, I do have a 93 civic VX and it gets 52mpg.
also ford ranger 22mpg,pathfinder 18mpg,harley 50mpg,19' boat 8mpg, 89 f-250 11mpg.

I also have 4 years of collage 2 auto menchanic 2 diesel mech.

I was a car mech for 3 years a tractor trailer mech for 2 years (hertz penske). then a ship mechanic for 16 years i am a fisrt enginnner and i make about 175,000 a year. and i have been around the world more times than i can count rome italy is my favorite city.
oh yea i can't spell for ****.

 

Whats the name of that college so I can avoid sending my kids there?

 

For someone with such worldly experience, you sure do seem blind to the reality. And no, I am definately NOT supporting your theory that lower RPM results in better fuel economy. It seems like you've neither read, not comprehended my posts. Regardless of what we say, you insist that we're all wrong without being able to provide ANY statistical data to back up your claims. Are we nay-sayers? Sure. But have you conclusively proved us wrong? Nope.

One would think that anyone with that much education, worldly experience, and earning that much money every year would know how to spell hybrid, first engineer (his job title), previous, wrote, and switches, or at the very least, know how to use spell check.

 

Yep, I told you, I've already tried the "driving like a Grandma" method to better mileage. It netted me ONE MILE PER GALLON. Yeah, worth it.

Kind of hard to take the ridiculously complex reactions of an internal combustion engine and explain it with "basic formulas of math" there bud. If it was that simple, we'd be driving perfect combustion engines (perfect combustion of gasoline results in two products: water vapor and CO2) and getting 300mpg...

Not that simple bud. The simplest way to explain fuel usage is based on flow. There are parts of every engine's flow curve that intersect at varying combinations of throttle position and RPM. This means that an extremely general rule would be to limit RPM, but there are some cases where an engine is more efficient at a higher rpm/smaller throttle opening.

Do you proof read anything? Speed equals velocity? Do you even know what these terms mean?

Let's assume by speed you mean engine speed (aka RPM). Wouldn't it be R/2=V?


I think you talked yourself into a circle, a very irregular circle (unidentified polygon? Maybe a rhombus?).

You're not taking into account what every modern EFI car does when you tip into the throttle too much. You see, halving your overall ratio is nice and all, the problem is you end up needing to floor the stupid thing to maintain 70mph. There are some problems problems with this:

1. Most of us drive automatics. If you floor it, you're going to (God forbid) increase RPMs.
2. When you floor a modern EFI car, your target A/F ratio changes, decreasing efficiency for the sake of reliability.

See this post for further explanation:

https://www.f150online.com/forums/sh...9&postcount=50

It was in this thread, you just responded with silly FoMoCo/Eco maniac marketing garbage.

 

He has 4 dollar words, 1 dollar brains, and fitty cent spelling...

 

As part of the whole-language (or "balanced") reading-instruction philosophy, many public schools now teach what they call “invented” or “creative” spelling. Under this theory of spelling, teachers believe that forcing a child to spell a word correctly thwarts the child's "creativity." So in classrooms across America, many public-school teachers now encourage children to spell words any way they like.

Also, many school officials now believe it is not important to teach correct spelling.


I imagine the nuns busted open your knukles when you misspelled a word.
if i wanted to i could spell and write gramaticly correct dot the t and cross the I's.

 

Found it on the internet, so it must be true.

 

I've been reading this thread with amusement and thought I would chime in with some real world experience. I used to be involved in tractor pulling. My super stock tractor had a one gallon fuel tank. I drove it down the road with no load one time at 3800 RPMs and made it about 3.5 miles before running out of gas. That weekend, I drug a 26000 + pound sled 180 feet at 3800 RPMs, unhooked, drove another 100 feet at idle and ran out of gas. According to Dancos theory of RPM/fuel usage I should have been able to pull the sled 3.5 miles on one gallon of fuel since my RPM was the same.
You can spit all the numbers you want but real world shows that RPM means nothing when it comes to fuel usage. In very simple terms, more work= more fuel, therefore, your truck could easily use more fuel in overdrive/lower RPM with a load then in a lower gear/higher RPM because the engine has to work so much harder in the higher gear to maintain the desired speed.

 

So, are you going to answer or reply to any of my questions, or are you just going to avoid them?

Driving everywhere at WOT to save gas by just shifting out short? Once again, have you not seen a fuel map before?

 

Why would anybody who makes that much money be hanging around here? If this guy seriously made that much he'd be too busy driving his new hummer around town picking up all the ladies, in which case he wouldn't be too concerned about fuel usage.

With that much money (and apparently too much time), he could buy one of those semi gear reduction thingys and pay a real engineer to design a way to bolt it in.

Isn't it funny how he came here asking a question and now he's answering it for us!