After extensive monitoring and calculating over thousands of kilometers consisting of multiple trips in various road and weather conditions, with and without aircon on, traveling north and traveling south - pretty much covering all variables I have determined conclusively, that my vehicle uses less fuel when I use cruise control.
Maintaining a cruising speed of 95 km/h (with and without using cruise control), my vehicle consumes an average of 18.7l / 100km not using cruise control and an average of 18.3l / 100km using cruise control.
*I thought it was implied but, notwithstanding, I will add that the fuel consumption figures I stated are when towing my van.
-- Edited by Mein on Tuesday 13th of July 2021 08:27:11 PM
I also discovered (as I've recently done some cold weather travelling) that my car does 6.9 in winter and 7.1ish in summer; I'm presuming its using the air-conditioner ( not that I'm wiling to wilt to save money) love my air con and cruise control. Recently we got caught in a dreadful dust storm and consumption went up to 7.5. I only have a diesel x-trail and don't tow hence reasonable fuel consumption
I've found it's very much depends on terrain and I know the responsiveness of cruise control on all of my vehicles differ greatly. Cruise control certainly means more consistent throttle movement when terrain changes gently and inconsistency is a real fuel chewer. Cruise control is a good way to help mitigate fatigue too and that's valuable for both fuel economy and safety. What I've yet to work out is the value of dropping revs and speed vs maintaining them on inclines and when I should drop cruise and when I should let it do it thing.
Colder air is a bit more efficient as it is a bit more dense. Found morning & winter driving a touch more efficient.
If the terrain is undulating I have found it better to let the car pick up a bit of speed downhill & loose a bit of speed uphill. Typically we drive at 95kph.
140kph uses twice the fuel compared to 90kph.
Headwinds as high as 12.5L/100, tailwinds as low as 7.8L/100.
Air conditioning makes no difference as otherwise I have to open windows & then too much noise.
All terrain & slightly wider tyres another 0.3L/100.
Can't really say how much all the rubbish on the roof increases drag as every trip has stuff on the roof.
Cruise control saves money, especially in 40kph road work zones & CBD areas (fines). My cruise control unfortunately does not go down to 30kph for Manly's CBD speed limit.
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Hello All.
I found using cruise control on flat or hill-less roads made little difference to fuel consumption while towing my van but made driving a bit more comfortable. On hilly roads, using cruise control caused a large increase in fuel consumption.
Like Whenarewethere writes, I get best fuel use letting rig accelerate a bit down hill and don't use enough throttle to maintain speed up a hill. Of course, for all interested in reducing fuel consumption, every time you use you brakes, you increase fuel use because you're converting momentum (latent energy) into wasted heat.
Cheers,
Roy.
I cant agree with the OP. A cruise control system works by a PID controller sensing mainly road speed. The cruise control function generally works pretty well in maintaining a set speed but it can not read the ups and downs of terrain until the speed of the vehicle drops. Most drivers when driving without the CC switched on actually anticipate hills and other changes and will make minor adjustments to throttle to compensate. You might want to call it *driving by the seat of your pants* but this minor changes influenced by the drivers sight and some other senses actually improve the smooth flow of the travelling vehicle and in most cases result in a saving in fuel. Just my own experiences for what that may be worth, I get a slight increase in fuel economy by not using the CC. I am not concerned with using a bit more fuel if the road terrain and conditions are such that it is safe to use the CC.
-- Edited by Clarky 1 on Tuesday 13th of July 2021 08:04:56 AM
I have every receipt from the day we got the new car for fuel & written on the back trip computer data. I don't actually care too much how much money we spend on petrol. I have done this more out of interest.
We mainly drive at around 95kph as it is more pleasant. If we drive faster we get to the destination 10 minutes earlier. So what. We only average less than 200km per day traveling.
We also use RON98 in the car most of the time as in does give longer range, which is useful in very remote areas.
We barely use the car in the city as we walk everywhere, it is simply easier.
As others have mentioned above if you are "using" the brakes in the outback you are wasting fuel. Our car has done 60k & at just replaced the rear pads for the first time.
In the city we use close to double the fuel at an average speed of 32kph.
So at the end of the day, drive gently to save fuel & maintenance costs. Get TPMS. If there are really strong headwinds call it a day if it is not necessary to get to a destination.
If we use double the fuel in these environments, it's worth it!
After extensive monitoring and calculating over thousands of kilometers consisting of multiple trips in various road and weather conditions, with and without aircon on, traveling north and traveling south - pretty much covering all variables I have determined conclusively, that my vehicle uses less fuel when I use cruise control.
Maintaining a cruising speed of 95 km/h (with and without using cruise control), my vehicle consumes an average of 18.7l / 100km not using cruise control and an average of 18.3l / 100km using cruise control.
My extensive non technical testing of using the cruise control when towing extrapolated an entirely different result, of approximatly 2l/100km more if CC is switched on.
In saying that one wonders what the net effect would the change would be when the gearbox type is taken into consideration.
Again by my non technical discussions with other GN's who tow a similar weighted caravan, at similar speeds with the same series of ranger but with an automatic gearbox, they struggle to get under 17l/100km, where mine with the manual gearbox consistanty delivers low 14l/100km
I did find out (many years ago), that in a auto gearbox Ford car, yes the cruise control, gave slightly better fuel consumption
Towing a caravan, with the same car, I found it hard to distinguish any great difference, if I used cruise control or not
Perhaps due to headwinds, tailwinds, hills, etc
In my present motorhome, which has a manual gearbox, I always use cruise control on the flats for convenience
On the hills, or in built up areas, I never use cruise control, for safety reasons
I always check my fuel consumption, as it will give an early warning, that something is wrong with the engine
Far too many factors like, weather, wind, road condition, terrain etc etc to give an accurate assesment. In my opinion.
But if you feel your figures are accurate, good luck convincing some of us!
Ian
My experiences are that when towing my van I use a little more fuel while I am using the Cruise Control.
i don't use the control in hilly or roads with tight curves.
There was a marked difference with improved fuel economy when I fitted a Torque Convertor Lock Up Kit wether using the C C or not but I need to add that the improvements were proportional to use.
Like many others I use the Cruise if safe and comvenient.
My newer car was doing 6 litres to the 100, until I put roof racks and an awning on, and a HD towbar now it is using 6.5 litres, Not bad for a 2.4 lt petrol
Far too many factors like, weather, wind, road condition, terrain etc etc to give an accurate assesment. In my opinion. But if you feel your figures are accurate, good luck convincing some of us! Ian
I tend to agree. The OP (thankyou for your thread) saves 0.4 litres per 100kms of travel. We are not concerned here about the money savings like 40 cents or so. But I would think a head wind for 20 kms would make up for that .4 litres.
Tony
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After extensive monitoring and calculating over thousands of kilometers consisting of multiple trips in various road and weather conditions, with and without aircon on, traveling north and traveling south - pretty much covering all variables I have determined conclusively, that my vehicle uses less fuel when I use cruise control.
Maintaining a cruising speed of 95 km/h (with and without using cruise control), my vehicle consumes an average of 18.7l / 100km not using cruise control and an average of 18.3l / 100km using cruise control.
*I thought it was implied but, notwithstanding, I will add that the fuel consumption figures I stated are when towing my van.
-- Edited by Mein on Tuesday 13th of July 2021 08:27:11 PM
I've also noticed this - doing the grocery run (a minimum 3.5 hours one way) one day, I decided I just couldn't be bothered to monitor speed, so I hit cruise control. Checked consumption, and it was lower (didn't crunch numbers). I find consumption is higher when it's too hot to drive with the windows down (so, 9 months of the year up here), because of air con. But I am not going to drown in my own perspiration for the sake of a few bob.
-- Edited by 2_Paws_Up on Wednesday 14th of July 2021 10:22:31 PM
Yes it can ! Just be aware the ECU tends to advance timing etc to keep power in higher gears and doesnt in my case seem to change down !! Not entirely durable for auto or turbo vehicles !! A high percentage are these days . Even more so when towing ..
When we had the last Nissan Patrol, I agree with you as being a manual I could drive the car for the best economy - both towing & not towing.
However the D-max wants to change from 5th or 6th gear back into 3rd, sometimes 4th with a corresponding rapid rise in revs on the slightest of hills with or without the van on the back. So I only use cruise control on the flattest of roads! Perhaps I should go back to Ceduna!
I complained to the dealer - all they said was "That's normal" but at the same time they say "I need to modify my way of driving to get the best fuel economy" ! I've tried to beat the transmission by placing it in "manual" but still get beaten on the next small slope when in auto. It's quite economical between 90 & 100kph. Even on the few roads that have 110kph stretches in QLD, I sit on 100kph. Our daughter & her partner recently visited us in Toowoomba. They found their economy in their car was fantastic at 100 but went up in the 110kph on the Hume Highway.
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