An article in (I think) last October's issue reported that one of the motoring organisations suggested that using cruise control was more economical than manual driving. I have long thought that, instead of "driving" uphill it would be better if I allowed my speed to drop by (say) 5 - 10 mph and then gradually increase again once over the crest. Have any definitive tests been done and ,if so, what improvement in consumption was gained.
Cruise control
- Thread starter Southerner
- Start date
Hello Geoff,
Like you I have mused over whether cruise control does save fuel over manual driving. I am sure someone has done tests, but I don't know their results.
I think it depend significantly on the type of road conditions, for example stop start city driving, or motorway, and what type of driver you generally are, do you accelerate hard away from the lights? or do you pull away more sedately? It also depends on the engine and gear box combination.
The most extensive use of cruise control is most likely on motorways or good A class roads, and here the ability of the system to sense the small changes in required load may be more frugal than a driver, but the systems is only responding after a change in the conditions, where as a driver may anticipate an incline. Where the cruise almost certainly wins out is that it keeps the vehicles speed much closer to the set speed than most drivers can, This might represent a fuel saving as most drivers tend increase their speed over long distances.
Under other conditions the opportunity to use cruise control may be limited, but it can certainly save money if it keeps you within the speed limits!
I am fairly certain that a professional driver would be able to beat a cruise control for economy over a a limited run, but could they keep up the level of concentration required? And in reality most of us are not that professional so my feeling is that they probably do save fuel, and tyres, and licenses.
I have Saab diesel with cruise, and find it very useful, even at 30mph - actually fairly critical where I live as we have a forest of Gorden Browns cash collection cameras. I also run a diesel Renault Espace, and I am trying to get cruise fitted to that as well.
Like you I have mused over whether cruise control does save fuel over manual driving. I am sure someone has done tests, but I don't know their results.
I think it depend significantly on the type of road conditions, for example stop start city driving, or motorway, and what type of driver you generally are, do you accelerate hard away from the lights? or do you pull away more sedately? It also depends on the engine and gear box combination.
The most extensive use of cruise control is most likely on motorways or good A class roads, and here the ability of the system to sense the small changes in required load may be more frugal than a driver, but the systems is only responding after a change in the conditions, where as a driver may anticipate an incline. Where the cruise almost certainly wins out is that it keeps the vehicles speed much closer to the set speed than most drivers can, This might represent a fuel saving as most drivers tend increase their speed over long distances.
Under other conditions the opportunity to use cruise control may be limited, but it can certainly save money if it keeps you within the speed limits!
I am fairly certain that a professional driver would be able to beat a cruise control for economy over a a limited run, but could they keep up the level of concentration required? And in reality most of us are not that professional so my feeling is that they probably do save fuel, and tyres, and licenses.
I have Saab diesel with cruise, and find it very useful, even at 30mph - actually fairly critical where I live as we have a forest of Gorden Browns cash collection cameras. I also run a diesel Renault Espace, and I am trying to get cruise fitted to that as well.
For many years I used to drive at constant speed when possible - getting cruise seemed to improve the fuel consumption by 5-10% because it does allow slight variation of speed - ie drops slightly on the uphill and rises on the downhill.
My previous outfit was underpowered towing but economy was better when allowing the speed to drop on uphill stretches.
My previous outfit was underpowered towing but economy was better when allowing the speed to drop on uphill stretches.
Combustion engines are at their most efficient when run at constant revs preferably at peak torque.
Cruise control is better then foot at achieving this because it alters the amount of fuel in very small amounts to maintain constant speed.
You would be surprised how much your foot goes up and down even at a constant speed on the flat - I notice now (when not on cruise) that as you gain on a lorry you tend to ease off the accelerator and when you want to overtake you press down a significant amount even though you have not really altered speed much and could probably have held constant speed for the whole maneouvre.
I generally use cruise as much as possible on motorways and think further ahead - much more relaxing and better for the wallet..
Cruise control is better then foot at achieving this because it alters the amount of fuel in very small amounts to maintain constant speed.
You would be surprised how much your foot goes up and down even at a constant speed on the flat - I notice now (when not on cruise) that as you gain on a lorry you tend to ease off the accelerator and when you want to overtake you press down a significant amount even though you have not really altered speed much and could probably have held constant speed for the whole maneouvre.
I generally use cruise as much as possible on motorways and think further ahead - much more relaxing and better for the wallet..
I use cruise control a lot for general driving (I'm a rep so do a lot of miles) however, I've never switched it on whilst towing - always been a bit wary as I figure that I can react to speed issues quicker. Although I have clocked up a fair few miles towing over the years, I'm still very cautious when it comes to speed / reaction times and the caravan. Would it better to use the cruise control when towing and any general advice when doing so? I'm not a woose when it comes to towing, in fact, I love it but have seen too many caravans upside down on the side of motorways so prefer to sit between 55 and 60mph and get there in one piece!
As a general rule I don't use cruise control whilst towing in the UK, however, when towing in France I use it all the time on their motorways, & yes it is more economical to use it than not too.
When adaptive cruise control is the "norm" or if I ever get a car with it fitted, then I'll certainly use it in the UK.
When adaptive cruise control is the "norm" or if I ever get a car with it fitted, then I'll certainly use it in the UK.
Spent last weekend at CC site at Tredegar House, Newport, South Wales, Nice Site, Thanks Wardens. back to the story:-
Left Exeter on M5 with 1700kg behind and set cruise control at 56. Other than a couple of touches to accelerate past slower vehicles, I didn't touch the pedals until reaching Bristol 75 miles later.
I also hardly saw any trucks, didn't have to pass them, they didn't have to pass me because we were travelling at their pace.
Very relaxing and uneventful.
Left Exeter on M5 with 1700kg behind and set cruise control at 56. Other than a couple of touches to accelerate past slower vehicles, I didn't touch the pedals until reaching Bristol 75 miles later.
I also hardly saw any trucks, didn't have to pass them, they didn't have to pass me because we were travelling at their pace.
Very relaxing and uneventful.
I use cruise control on motorways and dual carraigeways only.
More relaxing. Cannot comment on MPG as I drive a LPG converted car, so really don't bother about that much.
Cheers.
More relaxing. Cannot comment on MPG as I drive a LPG converted car, so really don't bother about that much.
Cheers.
Greetings,
For some time now I have driven in a very fuel effecient manner in order to maximise the savings in fuel.
I have taken to driving at an indicated 60mph on motorways using cruise control. Having used the on board computer to check, I can say that this speed is equivalent to 57mph actual. I cannot describe the difference this has made to both the savings in monetary terms and the reduction in stress.
My 2.5Tdi Audi A6 returns 50mpg when driven in this manner and when towing, if cruise is used at 50mph I return a healthy 30mpg.
What I can't understand is the no. of people still belting past me doing well in excess of 70mph. How can we complain about the cost of fuel if the masses are still prepared to 'throw it' away.
For some time now I have driven in a very fuel effecient manner in order to maximise the savings in fuel.
I have taken to driving at an indicated 60mph on motorways using cruise control. Having used the on board computer to check, I can say that this speed is equivalent to 57mph actual. I cannot describe the difference this has made to both the savings in monetary terms and the reduction in stress.
My 2.5Tdi Audi A6 returns 50mpg when driven in this manner and when towing, if cruise is used at 50mph I return a healthy 30mpg.
What I can't understand is the no. of people still belting past me doing well in excess of 70mph. How can we complain about the cost of fuel if the masses are still prepared to 'throw it' away.
Its not just fuel they are using! there is added wear an tear on tyres and brakes and the road surface. Whilst fuel is probably the biggest single cost the others also build up.
As somebody who drives a dirty evil smelling gas guzzling 4x4 at speeds of around 70mph where appropriate and legal, I'm begining to feel persecuted even on caravan forums. Perhap it would be better if they just changed the law back to the good old days when we crawled along behind a man with a red flag.
Maybe, just maybe some of use think that our time is more valuable, so we don't mind the extra cost. I didn't realise that people like me offended so many people like you.
Steve W
Maybe, just maybe some of use think that our time is more valuable, so we don't mind the extra cost. I didn't realise that people like me offended so many people like you.
Steve W
I try to think about it this way, if I can get more miles to the gallon then I am giving less to Dictator Brown
i use cruise control because its relaxing and when set at legal speeds you dont have to worry about speeding fines and points on your licence
and to be honest ive never thought about mpg
hgv dave
and to be honest ive never thought about mpg
hgv dave
Awe Steve W, sorry your feeling persecuted :0)
Think you've made an important point though 'appropriate and legal speeds'.
If you enjoy driving a 4x4 at sensible higher speeds and pay the extra fuel cost that's your decision. Like Fred I get satisfaction paying the government as little tax as possible and doing a little less damage to the environment, I can always find something better than a new kitchen for an MP's 2nd home on which to spend the cash saved.
Like HGV dave I find the biggest benefit of Cruise is that it makes driving/towing so much more relaxing and enjoyable.
If I set the cruise early in my journey I havn't got used to the higher speeds so I'm happy cruising along at HGV pace.
Think you've made an important point though 'appropriate and legal speeds'.
If you enjoy driving a 4x4 at sensible higher speeds and pay the extra fuel cost that's your decision. Like Fred I get satisfaction paying the government as little tax as possible and doing a little less damage to the environment, I can always find something better than a new kitchen for an MP's 2nd home on which to spend the cash saved.
Like HGV dave I find the biggest benefit of Cruise is that it makes driving/towing so much more relaxing and enjoyable.
If I set the cruise early in my journey I havn't got used to the higher speeds so I'm happy cruising along at HGV pace.
Hi Thorpeo,
Ifeel so much better knowing that you feel sorry for me, as I thought I was the only one.
As for cruise control, I find that the fuel consumption actually goes up on my Sorento Auto. When I engage cruise, the torque converter lock up drops out pushing the revs up by about 450-500 rpm for given road speed and does not re-engage until a dead flat road or going down hill. Extra fuel used when towing with cruise engaged is 3mpg compared to using a light right foot.
Steve W
Ifeel so much better knowing that you feel sorry for me, as I thought I was the only one.
As for cruise control, I find that the fuel consumption actually goes up on my Sorento Auto. When I engage cruise, the torque converter lock up drops out pushing the revs up by about 450-500 rpm for given road speed and does not re-engage until a dead flat road or going down hill. Extra fuel used when towing with cruise engaged is 3mpg compared to using a light right foot.
Steve W
Hey Steve,
shhhhh
someone may be reading. I vill say zis only vonce, and for your ears (eyes)only I don't want to join you on the persecution list, I drive a 2.9 Sedona auto, highest VED rating, perhaps not quite as thirsty as a Sorento.
I had a pedestrian shake his head despairingly watching me pass with 7m of twin axle behind a month back.
Shhhh.
Hopefully the woolly beards won't see this post.
Please read and destroy
shhhhh
someone may be reading. I vill say zis only vonce, and for your ears (eyes)only I don't want to join you on the persecution list, I drive a 2.9 Sedona auto, highest VED rating, perhaps not quite as thirsty as a Sorento.
I had a pedestrian shake his head despairingly watching me pass with 7m of twin axle behind a month back.
Shhhh.
Hopefully the woolly beards won't see this post.
Please read and destroy
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