I was just watching a hypermile video on You Tube. He said the secret was to accelerate hard in electric mode. IS this true? What does accelerating hard do?

 

The FEH traction motor can only deliver a finite amount of horsepower, nominally 22. Heavy acceleration will instantly demand more power than the EV mode can deliver, so the computer commands the ICE on. Net result, lower FE. When the ICE is ON, FE goes down. And hard acceleration costs MPG on any vehicle, hybrid or not. Just remember, GENTLE on the pedal

 

Thanks, I thought so. I don't understand why that "hypermiler" made that comment while driving his Prius.

 

Nick,
People say the darnest things. I did read once about driving techinques for the Honda Insight with a manual tranny, that suggested quick acceleration from a dead stop up to a certain speed, but I can't remember all the specifics. That was the exception, not the rule.

But I can say with 100% confidence, that 99% of the cars on the road today, hybrid or not, will exhibit much better FE with gentle acceleration at any speed, especially from a dead stop. Laws of Physics still apply, and accelerating a mass from a dead stop takes a lot of energy.

Think about an airplane, accelerating from a dead stop on takeoff - The jet or turbo engine revs up to maximum just to get the beast moving. This same energy will easily maintain level flight @ 350 knots speed. No different in a car; takes a lot of power to accelerate.

 

Thanks Ken. What you said makes a lot of sense.

 

I was under the impression that the best way to accelerate (let say from 0-55mph) in an FEH was to use EV to 25-30mph (EV limit) and once the ICE kicks on go to 1800-2200 RPM and hold that RPM using "fake shifts", finally reducing to lowest RPM as you reach 55mph. This uses the eCVT and the first torque rise of the ICE. Am I wrong? (Also assume that there's a cruise distance to allow for battery recharge). I know my '08 FEH loves to be in that 1800-2200RPM range once it leaves EV all the way up to cruise speeds.

I also realize that sometime the EV only acceleration isn't possible due to traffic "demands."

 

To "fake shift", does it require letting up on the gas just before you feel it going into the next gear?

 

Yes, but there's no feeling it going into the next gear. You have to use the tach (and maybe the seat of the pants feeling/engine sound).

With the CVT there is no "gear shift" in the conventional sense. Thus if you push down the accelerator to a specific point the computer will respond with a corresponding RPM. The computer then uses the "virtually unlimited" gear ratios in the CVT to apply the ICE (and possibly EV) torque to the drive wheels (hopefully with the most efficient ratio with respect to engine load). As you reach higher speeds you may find it helpful to encourage the computer to go to a lower RPM and the CVT to a higher ratio. Your slight (or not so slight depending on your need) release of the throttle is the "Fake Shift".

I didn't come up with the term or the method but I can assure you it does make a difference when working to get the best FE. But for the record you don't have to do it as the computer is pretty smart and does a decent job of it on it's on (as seen when using the Cruise Control).

 

Thanks!
Are there specific rpm numbers to know when to "let up" on the gas?

 

My logic would be that the best gas mileage comes from accelerating in EV mode as hard as you can without going into ICE mode. Maybe it comes with practice, but I've been a little frustrated at how quickly the ICE comes on in acceleration. It's not much horsepower but the motor has great torque and I would expect to handle a bit more acceleration than the program seems to allow.