National B Eco challenge, unrealistic?

[Omnis]

Ive always wondered if all post 1990 fuel injected automatic cars are like this? So if you stay in D the car will use fuel while coasting but if you drive it in "overdrive" 3rd or 2nd and the car is rapidly deccelarting it wont?

Most slushboxes shift into neutral when you're braking to a stop. Engines don't inject fuel while decelerating. Naturally, idling in neutral uses more fuel than a decelerating engine-- fuel energy is not spent while energy from the wheels turns the engine.

The whole idea of hypermiling in an auto and engine braking through 2nd and 1st gear to a stop is to prevent the transmission from going into neutral and maintain the engine in a decelerating, fuel-cut state for as long as possible.

 

[novcze]

.... These are extreme hypermiling techniques.

I wouldn't call engine braking extreme hypermiling technique, everybody with brain is doing that.
I hardly use brakes when going downhill at steady speed, just controlling speed with right selection of the gear.
And downshifting while braking is also one of my habits if I don't need to slam on the clutch and brake in some unexpected situation.

 

[Omnis]

Tongue in cheek, over-the-top hypermiling techniques.