Using Cruise Control for best economy

Discussion in 'Tech/Mech General' started by steveclecy, Jul 14, 2011.

  1. steveclecy

    steveclecy Read Only Funster

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    How do you use your Cruise Control (assuming you have one)? I like bumbling along around 62 mph on Motorways/Autoroutes and the Cruise Control is just great for that. But what about hills? Do you disengage to "feel" your way up the hill? After our break in France and over the Massif Central I got to wondering just how much throttle is being applied. Would I be better changing down a gear or two and using higher revs or just allow the Cruise Control to apply up to maximum throttle in top gear if that was enough to get me up the hill.

    I am guessing that when a hill slows the MH below the preset speed, the system will apply full throttle until that speed is achieved again, which may not be the most economic way.

    Steve
     
  2. tony_g

    tony_g Funster

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    yes, that's my instinctive feeling but would be interested to hear from more 'tech savvy' funsters. If a hill slows me below my preset speed I reset to the speed prescribed until I feel it appropriate to speed up or I 'normalise' at 1900rpm, which seems to be the default economy setting for my 2.2 Ford Duratorq TDCi (140PS but chipped to 175PS)
     
  3. pappajohn

    pappajohn Funster Life Member

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    different for me having an auto box....

    on hills i either disengage cruise or drop out of overdrive, depending how steep.

    in cruise mode, trying to maintain 55mph on a slight, but long incline, will see my revs increase from 1800 to well over 3500 with possibly two downchanges.

    the same hill, cruise off, will need a little more throttle but usually stays in overdrive or possibly changes to third, and a slight loss of speed.

    i may have 300+ horses and 400 odd ftLB of torque, but they are lazy horses.....a sporty engine it aint.

    cruise will do anything it can to stick to the set speed going up hill and is very uneconomical.
     
  4. Movin' on

    Movin' on Read Only Funster

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    I have found that if my vehicle starts to struggle, it takes itself out of cruise and reduces speed.
     
  5. pappajohn

    pappajohn Funster Life Member

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    i think about 10mph below set speed and it will auto disengage to save undue stress on the engine.
     
  6. DuxDeluxe

    DuxDeluxe Funster Life Member

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    Haven't got cruise control on the van (wish I had) but on the car I always get the impression of a heavy throttle to bring it back up to speed. I never really thought about it before, though. Technical explanations welcome..........
     
  7. pappajohn

    pappajohn Funster Life Member

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    as in my post....the cruise will do anything in its power to maintain the set speed.....and get back to it as fast as possible.


    my engine is very quiet in cruise, but on a hill the beast is woken, the silence broken.
    a 6.8ltr V10 at 3500 revs spinning a cooling fan the size of a bicycle wheel will never be quiet :Sad:

    manual box, more and more throttle yet less and less revs.....wasted fuel

    auto box, downchanges and more revs......wasted fuel
     
  8. DuxDeluxe

    DuxDeluxe Funster Life Member

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    Thanks - being a bit slow tonight..... You'd think that modern electronics would handle it a bit better than simply giving it loads of gas, but in the big scheme of things I suppose there are other priorities for auto makers.

    Trying to remember electronic controls I did for my 1st mates ticket years ago but never understood it then either
     
  9. bernardfeay

    bernardfeay Read Only Funster

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    i have a 2.2 litre ducato with cruise control. My pal has a similar size mh with a 2 litre ducato engine. He does not have cruise control. We set off from home together and got to our need for a fill up. We both started out full. I had to put £82 in and he had to put £92 in. H

    Lots of variables of course but I also like to stick at 62 mph. He followed me all the way up the motorway but of course our overtaking abilities were different.

    If I feel the engine is struggling in 5th going up hill I drop down to fourth and put the cruise back on.

    Probably, like all other ducator owners I have to rely on the sat nav for my true speed.
     
  10. callumwa

    callumwa Read Only Funster

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    I have a Peugeot 2.2 HDI, 6 speed, with cruise.

    On uphill stretches I disengage the cruise, use a light left foot and often let the speed drop a few mph. I then regain the speed very slowly on the next flat or downhill stretch.

    If you watch the instantaneous mpg on the fuel computer, if you leave it in cruise it drops like a stone, but if I use my light right foot and let it drop a couple of mph it hardly changes. Far better mpg can be obtained without the cruise on as opposed to leaving it on all the time. I am getting about 28/29 mpg on a good day. 25/26 on a bad day. I hope to get it remapped before we set off for France next month, so hopefully that will help improve the figures and maybe crack the 30 mpg...:thumb:

    My car is a Honda Civic 2.2, 6 speed turbo diesel. The cruise on it is amazing, extremely sensitive and seems to "think" as opposeds to just maintaing the speed at whatever cost. It has an ECO (economy) gauge on LED's as well as the LCD fuel computer. Last time I had a long run up to Scotland and back I achieved 63 mpg sitting "just" above the 60 or 70 mph speed limit as appropriate. Even on long uphill stretches in 6th gear at 70 mph, it still shows just under 50 mpg on cruise.
     
  11. simsy56

    simsy56 Funster

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    I use cruise a lot, but, only on level roads or slight inclines. I always knock it off on hills as with an auto box the engine will start to rev a lot higher to try and maintain the set speed. Much more economical to relax on climbs, than scream the engine chasing an unobtainable speed setting.

    Craig
     
  12. steveclecy

    steveclecy Read Only Funster

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    Thanks for your thoughts. My impression has been that it is better to knock off the Cruise Control on long inclines as your right foot is more sensitive than the Cruise Control. I think CC is a "switch" between power and no power.

    Steve
     
  13. parkay3560

    parkay3560 Read Only Funster

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    Interesting thread this. I say so because I am a disabled MHer and have cruise control on my Quashqui and its fantastic and eases my back off when I drive. I now dont go that far in my MH cos I cant manage to drive long distance any more so cruise control would be fantastic for my 2004 Fiat ducato based MH, our Bessie E435.

    appologies for appearing to hijack the thread and if any answers come out of this I'll move to another, but has anyone had cruise fitted to the same cab as I have and does it work and is it expensive?

    apologies again for any hjack.

    Bessy regs

    Kenny
     
  14. buttons

    buttons Funster

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    I can speak with a considerable amount of expertise in economy driving:Wink: cruise control is a pleasure but will definitely not replace the right foot for the best economy. Staying at a constant speed is not the most economical way to drive. If you are going downhill then let your speed pick up and uphill let your speed come down slightly. If you dont believe me then monitor your real time trip computer.
    Long distance motorway driving with cruise set at 74mpg I will get 3-4 mpg less than using my right foot, but worth every lost mpg:thumb:
     
  15. Taran_Las

    Taran_Las Funster

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    For retro cruise control fitting:
    Have a word with Dave Newell - www.davenewell.co.uk/
     
  16. parkay3560

    parkay3560 Read Only Funster

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    thanks for that link..and going to have a nosey now :) Boridah!
     
  17. Glynn

    Glynn Read Only Funster

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    I would "Never" take much notice of the fuel cons computer, the only way to calculate mpg is to do a fill drive fill test. I have a few vans with computers and for example they might say 30 mpg where as the real mpg is about 24 -25.
     
  18. DuxDeluxe

    DuxDeluxe Funster Life Member

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    You right about the lack of accuracy with trip computers and their optimism but for the purposes of this thread, the instantaneous consumption indicator is a great guide since you're looking for an indication only.
     
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  19. buttons

    buttons Funster

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    Spot on DD:Wink:
     
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