Cruise Control Saves Petrol ???

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A friend has suggested that using cruise control whenever practical will
reduce petrol consumption. Any comments?

 

[Edward Hayes]

I've found that the cruise control indeed saves gas on longer
trips(50+miles)on generally level road. On my Forester At mileage increases
about one mile per gallon. However if I use the cruise in very hilly terane
that it does not and infact reduces mileage sometimes. ed

 

[Jim Stewart]

I've found that the cruise control indeed saves gas on longer
trips(50+miles)on generally level road. On my Forester At mileage increases
about one mile per gallon. However if I use the cruise in very hilly terane
that it does not and infact reduces mileage sometimes. ed

Exactly. I've also noted that I tend to set the
cruise control a little faster than I normally
drive and that doesn't help either.

 

[Cam Penner]

A friend has suggested that using cruise control whenever practical will
reduce petrol consumption. Any comments?

In general, and especially on open roads, true. You use
much less fuel keeping a constant speed than you do
accelerating. Just don't set the cruise higher than you
normally drive and you WILL save fuel.

 

[Rick Courtright]

A friend has suggested that using cruise control whenever practical will
reduce petrol consumption. Any comments?

I've seen this as suggestion for increasing fuel economy from many
sources. IME, even though I do a lot of long distance driving, little of
it is traffic free enough to feel comfortable leaving the cruise on long
enough to see a difference.

OTOH, a friend has a big V-10 Ford pickup, and he sets the cruise at 60
on the highway and ignores the traffic stacking up behind him. He claims
it's usually good for about 1 mpg which is significant considering his
truck usually only gets 12-13 mpg. This is strictly YMMV!

Rick

 

[Don]

A friend has suggested that using cruise control whenever practical
will reduce petrol consumption. Any comments?

It used to save more gas in the olden days of carbs and accelerator pumps. Every time you accellerated it would squirt in gas, but that's not true today with fuel injection. But, it still saves on gas mileage because it won't try to keep up the acceleration of the GMC Subdivision going up a hill.

Try it yourself. Measure the elapsed time to accelerate from a steady 30mph and use cruise control lever to accelerate up to 60. Do that again using your foot rather than the cruise control lever. (Hopefully) it will take longer using the CC to get from 30 to 60.

Although it very well could be the CC system is smart enough not to inject more gas than the engine will burn efficiently, again VERY unlike a carb'ed engine.

Just my 5c worth.

The main place I feel it saves me is at driving the speed limits. I drive until the engine "sounds right", usually very much over the speed limit!
Username munged by FixNews

 

[Ignignokt]

In general, and especially on open roads, true. You use
much less fuel keeping a constant speed than you do
accelerating. Just don't set the cruise higher than you
normally drive and you WILL save fuel.

Alternately, cruise can let you travel between destinations more quickly
than without it: Let's say that the local police force will leave you alone
until you exceed 10 mph over the speed limit. When travelling without
cruise control, one is obliged to leave a bit of a safety margin between his
speed and the "10 over" limit that will earn you a citation (and not the
"good" kind of citation), so that a momentay lapse in attention doesn't end
up costing you. When I ride my motorcycle -- which obviously has no
cruise -- I generally aim to travel somewhere between the posted limit and 5
over the limit. This gives me a bit of a safety margin to accommodate such
things as cresting a hill, where my speed might drift up if I'm not paying
close enough attention. When I drive a car with cruise, I can set it at 9
mph over the limit and leave it there, confident that I won't drift over
that magical "10 over" limit. On short trips, this difference is negigible.
When travelling hundreds or perhaps thousands of miles, it can add up.

Of course, as has already been mentioned, cruising at a higher rater of
speed will not save fuel. And using your cruise at a slower speed will also
prevent you from doing that "wait until Greg passes you and then speed up to
follow him" syndrome that has caused me to wonder whether my Forester has
some sort of powerful magnetic attraction to other vehicles. And I
have to concur with the sentiment that it will only save fuel if travelling
on level terrain. When traversing significant grades (and "significant"
depends a lot on the vehicle), cruise can actually *cost* you fuel, by
working your engine harder to maintain up-hill speeds than you would with
your right foot manually controlling things.

- Greg Reed

 

[JW]

A friend has suggested that using cruise control whenever practical will
reduce petrol consumption. Any comments?

In five 1000 mile gas mileage tests each my foot beat the cruise control
by an average of 2.79 miles per gallon. However, I like the cruise as it
allows my foot to rest during these trips! Mine is a turbo vehicle
however, so the cruise is much more aggressive in acceleration than I am
which may account for the difference. You touch the resume button and it
gets there right now!