This week we
will examine driving habits that can affect your fuel economy. One of the first
ways that you can increase your fuel economy is to use your cruise control. The
engine electronics system can make a smoother throttle transition then the
majority of drivers are able to do, thereby increasing their mileage.
Slow down. The faster you move, the harder your
engine has to work to push through the wind. Speeding can reduce fuel
efficiency by up to 33 percent. Factors
other than air resistance decrease fuel economy below about 60 mph
(97 km/h), so fuel economy is not a reason to go slower, but fuel economy
decreases rapidly above that speed.
Avoid braking wherever possible. Braking wastes energy from fuel that
you have already burned, and accelerating after braking consumes more fuel than
driving at a constant speed. On city streets watch ahead and coast when you see
a red light or traffic jam ahead.
Avoid excessive idling. Idling a vehicle wastes a
significant amount of fuel. The best way to warm up a vehicle is to drive it
slowly until it reaches proper operating temperature. In cold weather warm the
car engine no more than 30 seconds. This period of time is sufficient to ensure
that the engine is properly lubricated for driving. Generally, if you can avoid
10 seconds of idling you will save gas by turning the engine off and
restarting. However, starting an engine too often can lead to excessive wear
and tear on the starter motor and wiring.
Find your car's "sweet
speed". Some cars get better
mileage at specific speeds, usually 50 mph (80 km/h). Your car's
"sweet speed" is the minimum speed at which the car is running in its
highest gear (watch for rpm drops as you accelerate to determine when your
transmission is shifting into higher gears). For example, most Jeep Cherokees
are best at 55 mph (89 km/h), and Toyota 4Runners are best at about
50 mph (80 km/h). Find your vehicle's "sweet speed" and
pick your roads accordingly.
If your car has an automatic transmission with overdrive, make sure you
enable overdrive except when towing very heavy trailers. Overdrive is by
default enabled on the "D" on most shifters. Several cars have
buttons on the shifter which allow you to turn off the overdrive gear. Don't
turn it off except in specific circumstances it may be needed such as for
engine braking downhill or failure to proceed uphill smoothly in overdrive.
Overdrive saves you gas mileage at higher speeds by using a lower ratio from
engine speed to wheel speed - this places the engine at a more efficient
operating point (by reducing throttling losses, etc).
Learn to watch and predict
traffic signals. In city
driving, study at what speed you can make multiple traffic lights, and slow
down before a light so you may not have to stop completely. Stop-and-go driving is wasteful. Don't circle in a parking lot, and keep well
away from the store fronts. Look for a spot in the empty half of the parking
lot. Many people spend significant time idling and creeping, waiting for a
"close spot" to open up.
Maintain a safe following
distance! Don't stick to the bumper of the car directly in front of you.
You will brake more and accelerate more to keep that unnecessary and dangerous
narrow gap. Relax. Hang back a bit. You're still traveling at the same speed as
the car ahead of you even if you're 100 yards (91.4 m) behind. This also
gives you a lot more room to play with when you are timing lights. When he
slams on his brakes, you can coast down and see if the light quick-changes
green again (some do). You might even coast by his car as the light turns green
and he has to accelerate from a dead stop.
