- May 12, 2011
Ride along as CleanMPG teaches us how to hypermile a Ford F-150 EcoBoost
Of course, if you fill the tank this much, you'll likely spill a bit of fuel. Automotive engineers prepare for situations like this and build in tiny holes right at the fill spout that drains through a stainless tube onto the ground. Gerdes said he puts a collection tub under this spout so that when he tries to save fuel, he doesn't instead pollute the ground. The important thing is to know that you're starting with a completely full tank (which can then be contrasted with how much fuel goes in on the last fill-up). The other component here is an accurate distance gauge. Before each headline-grabbing road trip, Gerdes and his crew make sure to compare the on-board odometer to 100-miles' worth of markers distance markers along the side of the road. With these two numbers in hand, Gerdes sets off, sometime pushing the truck to the best spot in the parking lot so that, once you've started the engine, you're instantly ready to move. It's as if wasting gasoline offends him – and why shouldn't it? There are free miles just laying everywhere, like in the slope of a parking lot, and most people just leave them sitting there.
Pushing a vehicle into position is just one more trick hypermilers can use to decrease the amount of fuel they need to burn to go anywhere. Hanging with hypermilers introduces you to a bewildering array of new terminology to describe these tricks: FAS (a Forced Auto-Stop, described above), NICE-on (Neutral, ICE on – like a FAS, but with the engine running), and Driving With Load, a key idea: you want to keep the engine at a constant, efficient rate while letting your speed vary (one journalist who participated in the Challenge before me, Jill Ciminillo of Chicago Now, has created a longer list for the uninitiated). One thing Gerdes does not recommend is drafting behind a truck, as that's a bit too dangerous.
Gerdes uses all these terms fluently, and his CleanMPG friends know what he's talking about when he does. They don't always agree with him on the forums, but on this trip, Gerdes was in charge, directing them from the F-150's passenger seat just as he directed me. I learned one lesson the time we came a railroad crossing at the bottom of a slight hill. We had been running parallel to a train for a mile or two, talking about how geeky some train fans can be (takes one to know one, right guys?) when we saw the flashing red lights down a ways indicating that the train was about to get in our way. "Shoot," Gerdes said, directing the driver at that moment to shift into M and then downshift into first gear. This made zero sense to me. We were going to have to stop anyway, right? So wouldn't this be one of the rare times when it's okay to step on the brakes? Of course not. There is never a good time to step on the brakes (well, almost never).
See, the trick – again – is to understand exactly how the vehicle you are driving works. In Ford's F-150 XLT with the 3.5 liter EcoBoost V6, that means knowing that the fuel cut comes at around 1,100 rpm. Oh, and it also means understanding what the fuel cut is.
Fuel cut is the point at which the engine will still use the vehicle's momentum to keep the engine turning over. Every internal combustion engine (except those with auto stop-start or an electric motor) wants to make sure that it continues to spin, otherwise it will stop running. (If you've ever driven a manual and stepped on the brakes without first stepping on the clutch, you know what we mean.) When the engine rpm drops below a certain point (in this case, 1,100 rpm), the car will send a bit of fuel through the injectors to keep everything humming along. This can be a complete waste if you're a hypermiler, because there is another way to keep the engine spinning: downshifting and fuel cut.
Thanks to the transmission, you can use the rotation of the wheels to spin the engine. If you downshift at a higher speed, the engine will spin faster (i.e., at higher rpm) as it slows down the vehicle – neatly preventing the computer from turning the injectors back on again while slowing down. This technique is called smart braking, and any time you're moving without burning fuel, it's called fuel cut.
Compare this to what happens when you step on the brake pedal during a normal stop in an automatic transmission-equipped vehicle: the torque converter unlocks and then all you have is the fluid coupling. This means that the drive wheels are spinning independently of the engine and the rpm number drops. Stepping on the brake pedal simply converts momentum to waste heat while still burning fuel. No one wants that.
As it turns out, the flashing red lights were for a stoplight, not a railroad crossing. But this turned into a teachable moment, one of hundreds for me along the journey. Gerdes knows that not everyone is willing to do stuff like this to cross the country in a heavy pickup truck using just over two tanks, saying, "That's us, that's not everybody."
So, how did we – the novice journalists and experienced CleanMPG members together – do? Overall, the 7,120-pound F-150 with people and gear managed 32.281 mpg over 2,468.7 miles. The Ford Fiesta chase car, similarly loaded and achieved, got 63.5 mpg. That pretty much confirms it: there are extra mpg laying around everywhere, you just need to know where to find them.
We asked Ford about some of these driving tricks, and this is the official, vetted response:
Again, we should make it clear that no one should attempt maneuvers like this without proper oversight, training and an understanding of the risks. Clear? Good.
First, we have to make it very clear that Ford does not recommend or endorse turning off the engine and coasting as a method to improve fuel economy.
We can tell you how the F-150 will behave in the unlikely event the engine should stall.
(1) The F-150 retains full braking power for a limited number of applications of the brake pedal, enabling the driver to bring the vehicle to safe stop as normal.
(2) The electric power assisted steering system remains active but not at 100 percent assist.
There could be instances where braking and steering efforts are affected. For instance, coasting down a long mountain road with the engine off could reduce voltage in the battery and affect the EPAS [Electric Power Assist Steering]. Also, the vaccum that powers the brakes would be depleted after several applications of the pedal.
And finally: We recommend filling the tank as per the instructions in the owner's manual.
One last thing: During a food stop in Sallisaw, OK, I asked the CleanMPG group to chat about the truck, hypermiling in general and how they deal with people who honk at them for driving slowly. Listen in:
(Download here. 16 minutes, 4 MB). You can also get more information on the journey over at CleanMPG or searching for #F150Challenge on Twitter. These guys know how to use social media.
Our travel and lodging for this trip were provided by CleanMPG.