2012 ford fusion RPM hack
 

My hybrid can`t maintain a constant speed on the highway at 2000 rpm, so i`m loosing the 40+ mpg`s. Would it be possible to put in a highway only manual switch and a resistor to fool the system. I want to run the engine up to 3000 rpm to maintain speed but tell the system it`s only at 2000 rpm to kick in the hybrid 40+ MPG. I can get 40+ MPG doing 80 mph if the road allows me to stay in the 2000 rpm range. There are probably more components to fool. The engine will easy rev 6000 rpm. Driving at 3000 rpm and making more oil changes would be worth the effort.

That's not really how it works, there's no "hybrid 40+ MPG".

The transmission in your car is a "power split device", a planetary gearset that keeps the engine at optimal load (high efficiency) and varies RPM to meet the power needs to push your car down the road. You need a certain amount of power to cruise down the road, and revving the engine up produces more power, but burns more fuel. You either get the power to go down the road from gasoline, or from the battery... and the battery is ultimately filled by burning gasoline too. Revving the engine up higher would burn more fuel, not less. There's no such thing as a free lunch.

Be aware that air resistance goes up by the cube of your speed, so driving at 80mph vs 70mph has 50% more air resistance to overcome for a 14% increase in speed.

If you want better economy, you have a few options:

1) Always drive downhill and with a tail wind

2) Reduce the drag coefficient of your car with modifications to aerodynamics. Some things you might try could include a partial grille block, an air dam or belly pan, smooth wheel covers and/or rear wheel skirts, kamm back or boat tail, passenger mirror removal or replacement with cameras.

3) Slow down - reducing my speed from 80 to 65mph nearly doubles my fuel economy, more than every mod I could do to my car put together

I completely agree with Ecky. If you lock your engine at 2000 rpm, you'll just gain speed going down a hill and loose it going up a hill. No need to modify this as you can just do it with your right foot. Your car needs more power to maintain speed going up a hill, that is why the RPMs increase. The transmission is already programmed to optimize your fuel economy.

no magic hack
 

There's no hack.

But ...

Extensive aerodynamic mods & higher tire pressure on my 2004 Prius (similar transmission to your Fusion) allowed me to cruise at higher speeds with lower engine RPM than normal, resulting in better fuel economy:

From: http://ecomodder.com/forum/showthrea...ing-32497.html

CVT's respond to ideally to mods, compared to manuals & conventional automatics.

I have no idea what RPM it ran at 70 or 80 mph though. I don't think I ever went over 65 with it. :D

I can get as good or better fuel mileage running up to 90 mph when running late for work as trying to drive 70-75 mph. I don`t believe the trans by itself controls fuel mileage there has to be more variables. It gets good fuel doing 80 or 60 if 2000 rps are not exceeded. 2000 rpm just cant be maintained constant for extended lengths of time at any safe highway speed. If running the car up to 80 then letting it slow to 70 and repeating gets decent fuel there has to be a happy medium. I want to fool the car to think its doing 2000 rpm not lock it in to 2000 rpm. perhaps a variable resistor device or program.

Hi. Might want to peruse this thread to see just how unusual that makes your car:

http://ecomodder.com/forum/showthrea...you-15182.html

It's not the transmission that controls fuel economy. You have to look at net energy in vs out, and it takes 66% more energy to push air out of the way at 90mph than at 70. Where does that energy come from?

If you have read the 100+ hypermiling tips(link at top right of this website) you would realize that maintaining a constant speed is NOT the most efficient option. When you allow your speed to vary, you open up a whole new world of gas mileage.


By drafting? You do know cars are a little more complex than just using a resistor right? It isn't like the car just DECIDES how much fuel will be burned depending on what rpm you are at.

Daschicken the law for following were I live is 3 seconds. Everyone else thank`s for your opinions.I still think somewhere in the controls ICE, Gas, Battery There has to be some adjustments for better speed fuel control, even if it pollutes a little. Mabie Volkswagen can help:). The car can`t maintain 70 mph on flat no wind road that`s not hypermiling, that`s struggling.

The mpg vs. speed link is incredibly pertinent. You have it in your head that the problem is "A" when the problem is actually "B". "B" is the laws of physics - where more speed creates more drag and more fuel burn and more rpm moves more air through the engine that requires more fuel to burn at the proper stoichiometric ratio regardless of what you trick the ECU into believing.

Here's the EPA rating for your car:
https://www.fueleconomy.gov/feg/Powe...on&srchtyp=ymm

41mpg highway.

You're not going to get much better than that especially at 70mph+

Here's a little reality check:

2008 Prius:
1.5L motor
2900#

At 75mph, I get 40-45 mpg.

2012 Ford Fusion Hybrid:
2.5L motor
3700#

Gas engine is 67% larger.
Car weighs 800# more.

But you think you should be able to beat a Prius (lighter and more aerodynamic) by spoofing the rpm?