How much does the so called "fake drag" impact fuel economy?

Not sure about what your question is? The fake drag isn't present all the time, only when you're coasting or trying to glide with foot off gas, but not on the brake pedal. Even then, you can force it to have no fake drag by applying just enough pressure to the gas pedal to take it out of battery regen. I think Toyota did it so it felt like driving a regular non-hybrid car. If Toyota eliminated it, not sure it would add anything to the EPA numbers. I also think if it didn't exist, you would use the friction brakes more to slow down, eliminating any gain from not recapturing the energy for regen.

 

it's not 'fake drag', it's regeneration. it's not 'siphoning off energy', it's recapturing what would be wasted energy.

 

I may be wrong, but I think the OP is referring to those instances where the ICE is "turning" and not being fed gasoline...and he's asking about the "frictional" losses of that "turning."

 

is that B mode?

 

As I understand it, "yes," the "B = braking" (in diesel-speak: Jake-brake), but I believe the OP is asking about those "other" instances when the ICE is being "turned/rotating" but is NOT generating HP.

 

you mean when going down a large hill with a full battery?

 

You can eliminate it by selecting "N" once the ICE stops running.

 

Or when above 42 mph and the engine running, "N" also works. It is simple, reproducible, and works.

Bob Wilson

 

There is no such thing as "fake" drag.
Either there IS resistance to forward movement or there ISN'T.
Either energy is being consumed or it isn't.
Nothing fake about any of that.

The OP needs to better describe his question.

 

The OP is talking about the regen that kicks in after gas pedal is lifted. This is to simulate the regular car engine braking action. I hate that feature myself, it would be easier pulse&glide without.

 

! ! ! BINGO ! ! !...we have a PC member with the A to the Q!

 

I detest the fake drag, it's a nuisance and should be eliminated.

 

Agreed, it SHOULD be a driver 'switch' selectable OPTION: ON or OFF.

 

The fake drag is simply a reversal in the operation of any motor/generator. It's a motor when energy is applied, and it's a generator when it's applying energy. A microphone is a speaker and a speaker is a microphone. There are trade offs when we need them to be one or the other. I happen to like the setup. I can use the batteries energy to turn the electric motor in my neighborhood or even going to the store for me. When I go down a hill, I lift my foot and use my motor to charge my battery back up simply by using kinetic energy that would normally be wasted while "jake braking" in a normal ICE in a non-hybrid vehicle. It would be a real pain to drive if I was constantly flipping switches. The way it is now, I just adjust with my foot. It sort of makes me feel more connected to the car the way things are now. My wife rolls her eyes when I say it, but I call it "Zen Driving". If that makes any sense.

 

I don't know exactly how much of the slow-down is captured as regen into the battery, but I'll guess not much since the regen efficiency increases as the power flow increases. Perhaps 15-20% ?

This is why I pretty much strive to either glide, or brake with 2 bars of regen. As said above, some people want to enter glide with NO pressure on the fuel pedal rather than a tad as it is now. I personally do not care.

 

I disagree.

 

that's real drag.

 

Mrs. Doubtfire has NO doubts!

 

You don't need the "FD" if you can stop at the signal/stop-light without ever using your "brakes". Well that is unlikely! So you want to get the most regen you can for that dreaded stop. Most of the deceleration might be done with the just the "FD" (no friction brakes), most of the rest of the deceleration can be done with more "FD-plus" (keep the indicator to the right 3/4 of the breaking area for no friction brakes), and finally you may have to use friction brakes for the last 10 feet of the stop. And yes, "FD" does make glide more difficult for those who care.