Cruise Control and MPG

Ultrasonic

Herzlos wrote: »

Have you used CC recently?

I've not driven with a modern system. As I said above, CC that automatically senses where other cars are may very well be safer than regular driving, My view relates to non-adaptive CC.

Ultrasonic

Trebor16 wrote: »

You can look ahead and anticipate with CC too. When you think you need to slow down you just deactivate it. Simples.

True. The two complications being the frequency that this is necessary and (at least for me) the reluctance to do so by virtue of being in the mindset of using CC.

Cornucopia

Sounds like you have "issues" with CC. I've had CC on every one of my past few cars, going back about 10 years, and I don't think I'd like to go back to not having it.

My recent cars have all been 1.5/1.6 low emission diesels, and my present car has a 6-speed automatic gearbox. It's a good combination, and AFAIK, the fuel consumption is the same with/without CC. It also has the capability to force a change of gear leaving the CC engaged - useful if the car is accelerating harder than you want it to.

The reason why CC is no less safe than non-CC is because a competent driver is driving the car they have, whatever its characteristics happen to be.

Trebor16

Ultrasonic wrote: »

My argument would be that your foot needs to move from further away and from a more relaxed state and is therefore bound to take longer to hit the brake than with 'normal' driving.

Your argument doesn't take into account the usual processes of anticipation and forward observation.

Trebor16

Ultrasonic wrote: »

True. The two complications being the frequency that this is necessary and (at least for me) the reluctance to do so by virtue of being in the mindset of using CC.

What is the CC mind set that you are talking about? I don't recognise it, I don't drive any differently with CC on and I still anticipate and read the road as much as I do without the CC on.

Richard53

AdrianC wrote: »

As Iceweasel says, all cruise does is to keep road speed constant. If the road goes up an incline, it'll use more throttle when the more economical action may be to let speed bleed off slightly. If the road goes down an incline, it'll close the throttle, when allowing speed to climb may build momentum for the climb coming up.

Agreed. My regular commute is a hilly A-road and I did an experiment a while ago. I reset the mpg computer before setting off and then aimed for the highest reading by various strategies, while maintaining normal road speeds, including using the CC set to 55 for the whole journey (conditions permitting). I found the best mpg was achieved by treating hills both up and down as if I were riding a bicycle: speed up a bit before an uphill to get some momentum, then gradually let the speed ease off as the gradient steepened, and then 'freewheel' down the other side (in gear, no throttle). This gave, from memory, about 2-3 mpg better than CC.


Remember that, in a modern car, if you are going downhill in gear with no throttle, you will be using no fuel at all, which is better than selecting neutral, when the engine has to use some fuel to maintain idle. I only say this because I have read advice in other places that the way to save fuel is to use neutral on downhills. Not safe, and defeats the object.

dannymccann wrote: »

manual driving (because I read the road ahead, ease off well before roundabouts etc) will see my average start pushing up to high 40's - a great achievement in a 2.0TDCI Mondeo, which for some reason is very thirsty in standard trim

gingerdad wrote: »

have to really try hard in my new mondeo to get mid 40's..

Really? I have a 2.0 Tdci estate, and I get 42-43 with short local journeys, and always over 50 on a run if I keep legal. For a fairly big, heavy car, driven briskly, I don't think that's at all bad.

Hintza

I would really struggle to do without cruise control especially when towing. As has been said it can be feathered easily and cancelled from the steering wheel.

If you guys aren't confident with it though it is probably best not to use it.

rdr

I think that anywhere with hills you need an auto gearbox for cruise control to be usable.
we had it on our previous car and I miss it on long motorway journeys as my right leg tends to get sore.
On non-empty roads you do have to make frequent adjustments and disenguage it early to bleed off speed when needed. As a tool to automate a part of driving some of the time it is useful, but not as a substitute for paying attention.

Incidently further to the driving like you are riding a bike, I sometimes take this a step further and turn the aircon off uphill and on downhill.

Running_On_Empty

I use CC occasionally but I use crowded motorways and dual carriageways where it isn't possible to use it safely . When I get chance I use it and find a marginal improvement in MPG. Mine is a 3.2 litre automatic.

Humbug_2

I love my CC. I find it works best at 60mph in the middle lane of any UK motorway!