I recall an article in one of the car magazines a few years back that addressed the driving habits that affected fuel economy. Most of their conclusions were obvious, but it was surprising that slowly accelerating a car to cruise speed can actually use more gas than quicker acceleration. The reason is that cars don’t hit their peak fuel efficiency until 40-50 mph, so if you take a longer time getting there, the car spends more of its time at less-efficient speeds. Of course, this assumes that you’re not racing away just to have to brake to a stop at the next light a block away.
In fact, if you have a manual transmission car, it’s been shown that heavy throttle, even full throttle, and short shifting (shifting into as high a gear as possible as quickly as possible) is the most efficient way to reach a given speed. The wide-open throttle reduces engine pumping losses past the partially-closed throttle plate and the short shifting reduces the frictional losses associated with high RPM.
So inching your way up to speed isn’t necessarily the most efficient.
Looking far ahead so you can drive smoothly to avoid braking trumps everything else. Braking is what sucks the living daylights out of gas mileage and is the reason hybrids get so much better city fuel mileage.
- Mark