How to drive the FFH for best mpg

[rfruth]

thanks WP, why doesn't the FFH have folding mirrors (the Escape hybrid does) anyone ?

[Oman]

It is not the size of the traction motor that really matters. There are two main factors that contribute to the max EV speed of the drivetrain:

 

1) If you look at the detailed specs you will see that MG2 can draw considerably more power than the battery can supply. This seems strange on the surface until you consider how the power splitter works. When the ICE is delivering maximum horsepower it is at a high RPM, but generally the car is moving slowly when it needs the power. In this mode MG1 is actually being turned in (we will call it the "negative" direction) to provide the RPM/HP conversion to high torque at low speeds. Essentially MG1 is stealing a bunch of power in order to perform the conversion. This power is not wasted however as the motive energy is converted to electricity that is then fed back to MG1. MG1 is sized to be able to draw max power from the battery and the ICE driving MG2 as a generator. So you need the smaller of the battery or MG1 have enough horse power to be able to overcome the total vehicle drag at a particular speed to be able to drive that speed in EV mode... along with #2 below

 

2) MG1 provides the conversion of RPM between the ICE and the drive wheels. In EV move the ICE is not turning. Therefore MG1 has to turn to make the difference between the drive wheels and the ICE. The maximum RPM of MG1 therefore determines the maximum possible difference in speeds between the input (ICE) and output (Drive) of the splitter. This happens to be 6400RPM which when converted through the final reduction gears and the tire size is about 47 vehicle MPH.

 

We have plenty of HP in a fully charged FFH battery to go well over 47MPH but the MG1 RPM limit kicks in. Thats why the ICE can turn at idle speed and the car can still cruise on 90% battery power well over 47MPH.

 

Jon

 

 

Just an update!

 

One month later, we see that Lexus is doing exactly what Ford did with the Fusion Hybrid drivetrain-- Going more aggressive on the electrical side.

 

Check it out: http://www.leftlanenews.com/lexus-hs-250h-...ive-review.html

 

The new Lexus HS250h will sport a 120hp MG2 electric motor. The Fusion Hybrid has a 90hp MG2. All the previous PSD hybrid sedans like the Camry Hybrid and Nissan Altima Hybrids had just 50hp MG2s.

 

I guess with such a big MG2, the Lexus HS250h will be able to cruise on electric alone at even higher speeds, if that's the case!

[Grey]

dup

[Grey]

I drove the FFH 100 miles this morning (NW Atlanta to Wedowee, AL) and took the shortest distance route. Averaged about 40 MPH and never got above 55MPH on the county roads. Several times I was able to set the speed control for 45 MPH (long stretches of 45 MPH secondary roads) and was surprised how many times I was in EV mode. Averaged 44.3MPG over the 100 mile trip over. Coming back I took the expressway and averaged 60 MPH (part of the trip was at 70 MPH) and got 39.6 MPG.

 

I am very pleased, and enjoyed the Nav unit. The minute I crossed into Alabama, it automatically set my clock back 10 years and 1 hour. :shift:

[cuehara]

I am very pleased, and enjoyed the Nav unit. The minute I crossed into Alabama, it automatically set my clock back 10 years and 1 hour. :shift:

 

lol nice. It's also nice how the nav notifies you if there's an accident along your route (if you have a destination set). Of course, sometimes the accident is clearing/cleared and others the accident doesn't cause any traffic.

[WPWoodJr]

dup post

[WPWoodJr]

I posted some tips for getting good gas mileage on my blog based on my experience with my new FFH.

[BearCat]

The minute I crossed into Alabama, it automatically set my clock back 10 years and 1 hour. :shift:

 

I could not help but crack up at this comment. :hysterical2:

[emillham]

I posted some tips for getting good gas mileage on my blog based on my experience with my new FFH.

 

Nice tips.

Personally, You won't find me driving down the road in neutral. I've avoided accidents before by quickly accelerating. To each his own though.

[WPWoodJr]

Nice tips.

Personally, You won't find me driving down the road in neutral. I've avoided accidents before by quickly accelerating. To each his own though.

Yeah I rarely do that either but it does help mpg.

[Oman]

Neutral does not exist in this car in any sense other than "ignore the accelerator pedal". There is no way to decouple the ICE from wheels other than by MG1 spinning. With the FFH software neutral is the same as holding the gas pedal just a bit off the stop. At that point the software does not implement the fake engine braking/energy recovery and is also not demanding power. Putting the car in neutral does the same thing but with additional risks as if you do step on the brakes you only get the friction brakes (there is a LOT of braking power in MG1 and MG2) and if you step on the gas to help get out of the way of a problem you won't go anywhere. It is better to learn the glide position of the accelerator.

 

Jon

 

 

Yeah I rarely do that either but it does help mpg.

[WPWoodJr]

Neutral does not exist in this car in any sense other than "ignore the accelerator pedal". There is no way to decouple the ICE from wheels other than by MG1 spinning. With the FFH software neutral is the same as holding the gas pedal just a bit off the stop. At that point the software does not implement the fake engine braking/energy recovery and is also not demanding power. Putting the car in neutral does the same thing but with additional risks as if you do step on the brakes you only get the friction brakes (there is a LOT of braking power in MG1 and MG2) and if you step on the gas to help get out of the way of a problem you won't go anywhere. It is better to learn the glide position of the accelerator.

 

Jon

By "just a bit off the stop" I assume you mean the point where applying more acceleration would demand power?