Gary: (I'll try to actually post something this time...<G>) I agree with you, but am trying to make a distinction between max load and WOT. There may be no way, with drive by wire to acheive max load without WOT, but I suspect that there is, and I am certain that WOT uses it's own non-closed-loop fuel map. On non-hybrid cars, the WOT map is usually pretty fat to make certain that folks don't melt or hole their pistons. SO, if the drive by wire pcm will let the vehicle achieve max load and NOT call for WOT that will be more efficient than WOT, and will likely be at the sweet spot for torque.

 

Willard and Mark, you both are making good points. True WOT is a condition of maximun airflow through the throttle body. It cannot be achieved with the electronic thottle body until RPM's are high enough to demand the max thottle angle for air flow. This is why for the most part, a cable is no longer attached to the accelerator pedal. The ability to use your foot to open the throttle is no longer possible for FE reasons. When I clarified that WOT was max (100%) engine load, I was stating the ICE was maxed in acceleration ability due to load.
With an accelerator cable, you could place the throttle angle at WOT, but the ICE could not accelerate any faster. At this point, you have motor assist taking over with torque. Very well done by the Ford engineers I might add. It only take the elec. motors a few seconds to assist the ICE to a true WOT RPM.

Willard, I have to disagree or maybe I'm not understanding you correctly with regards pumping pressure. From my research, many engineers are saying it is more efficient to have pumping pressure (vacuum). It's been awhile since I read that stuff, but it stated that the pumping loss did not offset the efficiency of the slower engine heated air flow moving through intake system. If we were talking WOT in racing where you want HP and quick torque, that a different story. The two subjects of Improved Hybrid MPG and WOT really don't go together I guess.

GaryG

 

During the first 30 seconds after a cold start, the RPM does not increase with moderate acceleration... also, I only see strong ( fat ) arrows coming from the battery pack, and none from the ICE. ( Nav screen )

As we all know, we must be very gentle to stay in EV taking off from a red light.
In EV, you have (about) 15,000 watts ( 20 horsepower ) from a red light.
During those first 30 seconds, you have 25,000 watts ( 33 horsepower ) of electric only acceleration, which is more than enough to reach 35 MPH before the gas kicks in at more than an idle rate. ( gas is burning at an idle rate during those first 30 seconds no matter what you do )

-John

 

To GaryG and all interested parties:

If you have Nav screen, or even just watch the stock "assist" needle carefully, you will all realize you can get battery assist at any speed, any RPM, and any load.

Just tonite, I was going downhill at 65 MPH and wanted to go 70 MPH.
Since I was on a downgrade, this did not require much additional torque.

I was "coasting" deadband at the time... no energy flow arrows.
I depressed the pedal.
I got energy flow from the battery to the wheels only, nothing from ICE.

Engine "load" ( if you can trust that, I say you can't ) was 30.
Throttle position sensor was 17. ( I was barely touching the pedal )
Manifold absolute pressure ( a measure of how "wide open" ) was 3.7 psi.
( Max at Denver is 12.4psi - so the throttle was nearly closed )

Gary, with very little load, and a nearly closed throttle, I was getting EV assist.
Why? It was computed internally to be the most efficient choice at the time.

Your theory of assist only at WOT does not hold water.
Electric assist does happen at WOT, but also at every/any other condition!!!

-John

 

Hi John

You wrote:
"Your theory of assist only at WOT does not hold water.
Electric assist does happen at WOT, but also at every/any other condition!!!"

It is not my theory and I did not intend to mean "assist ONLY at WOT". There have been many times as I reapply gas pedal, the electric motors assist. Generally, the engine shuts down though. If you were over 40mph going down hill, I have no trouble understanding what you said happen.

GaryG

 

Ever listen to an air compressor motor if you block the air intake? It will "load up" in the same way it does as the air pressure in the storage tank climbs.

 

Hi All

Closed-loop power control for hybrid electric vehicles

Here is a Ford patent that some of you newer owners may want to take a look at regarding how things work. Click on the PDF for drawings etc.

A control system and control method for a hybrid electric vehicle powertrain having an engine, an electric motor and an electric generator with gearing for effecting split power distribution from separate power sources. Power delivery to vehicle traction wheels is coordinated to meet a driver's demand for power as much as possible without violating predefined maximum and minimum powertrain limits, including the limits of the battery subsystem.

http://www.freepatentsonline.com/6991053.html

GaryG