nlc wrote:
For fuel: on my vehicle it consumes less in engine braking, since no more drop of gasoline is sent. While stalled, though, because of slow motion. I think it is the same now with all recent vehicles, gasoline or diesel (but I'm not sure).
Indeed: on all sequential injection gasoline engines (often an i in the 1.4i genre designation), the quantity of gasoline injected is continuously calculated as a function of demand (accelerator pedal, speed, lambda sensor, etc. ..). When you use the "engine brake", there is no fuel injection, while when disengaging, the engine runs slowly and we consume! This can be seen very well if you have an on-board computer that displays the instantaneous consumption: you take your foot off the slope, and presto, it displays 0!
If in doubt: open the hood. If you see a good old carb, it's not multipoint injection. In this case, we will see small injectors, fed by a small gasoline line, on the intake manifolds (all carefully hidden under plastics which "look" the engine).
Ditto for modern diesel engines with calculator (all direct injections, but also many TDs that are already 10 or 12 years old).
So, in this case, to save:
1) Above all, do not disengage !!!
2) But to anticipate et lift the foot : the ideal would be to lift your foot early enough (and therefore drive with a consumption 0) to arrive at the obstacle (turn, stop, growth, entry into town) at a speed low enough to no longer have to brake or very very little !
Two additional remarks:
1) Contrary to what we think, we hardly waste time !!! On a 20-minute journey (my home-work tarjet), between driving the most "speed" possible and the most economical, on average, less than a minute of difference!
2) On the other hand, I "scratch" more than 1,5 l per 100 km of consumption on average.
I recently had a car with a computer that allows me to record all of this, it's very impressive.
Hence the rule: "to brake is to consume !!!"
Do not divert and make accidents by refusing to brake. But use in anticipation: entering the city at 250 m, I lift my foot and I arrive almost point-blank at 50 km / h on the spot !!!