Quote:
Originally Posted by christofoo
(Doax beat me.)
P&G(/EOC) is the best way to treat hilly terrain. The gains are on the downhill. The only point of DWL, for example, is to avert downshifting in an auto. The end-game should always be minimizing total number of revolutions (barring WOT, lugging and braking).
If you never get into neutral it tends to be a wash (barring WOT, lugging and braking).
Conventional tranny Otto-cycle vehicles have only 2 efficient modes: brisk-acceleration (or up-hill) and neutral (EOC incrementally better than Glide [engine-on]).
|
I would agree with this. My 2012 Grand Caravan will glide in gear with little engine holdback and will shut off all fuel so the downhills really make up the fuel lost on the climb IF you stay off the pedal. Whereas coasting down in neutral shows 2.5 L/100kms and maintaining load shows the same 5-9 L/100kms it would get on a level. On the climb I use enough gaspedal to hit my maximum speed at the bottom and just hold enough throttle to keep it above the 60kph downshift speed at the top. I may accelerate slightly over the crest if there is not enough slope to do so on the other side, otherwise I let the slope do the work in gear with my foot off the gas.
Other auto transmissions did not work quite the same. 2000 Jeep Cherokee would downshift at about 75kph on a hill climb, really wrecking fuel mileage so I had to keep it above that speed. 97 Taurus still fuelled the engine with foot off gas and had lots of hold back so I used neutral a lot.
Using these techniques (that you guys have been teaching me!) I have seen tanks of 5.8-6.5 L/100kms in my Dodge Caravan over 400-1000kms. My Cherokee showed me tanks of better than 10L/100kms and the Taurus actually broke 7.8L/100kms when values of 9/15/11 are more common for these vehicles. Grand Caravan is regularly showing me 750-800 kms per tank and as much as 1100 on flat highway trips when it used to be as low as 400kms (and still is in winter and city driving).