ChatterBank0 min ago
Fuel Consumption And Cruise Control
Greetings
Until recently I was always lead to believe that cars with automatic gearboxes used more fuel than manual. I was told many years ago to expect 10% less in an auto. Apparently not.
Last year I changed my Mobility car to a Vauxhall Meriva which according to the brochure gave greater mpg in auto than manual. OK I'm not going to assume the figures quoted are correct but on checking a few other makes they all claim this does appear to be true.
My real query though is the use of the cruise controls. Due to circulation problems in my lower legs I thought I would give this a try and believe me it has been a godsend especially on the longer motorway journeys.
Do you think that using the cruise control in all situations - including urban - will improve the m.p.g. or not? Personally I am unsure as it seems to me that on even low angle descents seems to change gears down but on similar gradients up it remains in the higher gear.
Would the fact that I have a diesel engine - my first in over 40 years motoring - affect it?
Until recently I was always lead to believe that cars with automatic gearboxes used more fuel than manual. I was told many years ago to expect 10% less in an auto. Apparently not.
Last year I changed my Mobility car to a Vauxhall Meriva which according to the brochure gave greater mpg in auto than manual. OK I'm not going to assume the figures quoted are correct but on checking a few other makes they all claim this does appear to be true.
My real query though is the use of the cruise controls. Due to circulation problems in my lower legs I thought I would give this a try and believe me it has been a godsend especially on the longer motorway journeys.
Do you think that using the cruise control in all situations - including urban - will improve the m.p.g. or not? Personally I am unsure as it seems to me that on even low angle descents seems to change gears down but on similar gradients up it remains in the higher gear.
Would the fact that I have a diesel engine - my first in over 40 years motoring - affect it?
Answers
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Auto gearboxes nowadays are much smoother and efficient than they used to be so the mileage 'gap' has decreased if not diappeared altogether.
Does your Meriva not have a minimum speed that the cruise control would work at? Mine won't operate unless the car is doing 40 or over (I think) which obviously makes it unusable in towns. Also (IMO) it would not be wise or safe to do so.
But theoretically as the cruise control would select the most efficient gear to maintain the desired speed I can see that it might improve fuel economy in an auto car but not necessarily in a manual car where it is incapable of influencing the gear selected.
Just thinking - I'm not an expert!
Does your Meriva not have a minimum speed that the cruise control would work at? Mine won't operate unless the car is doing 40 or over (I think) which obviously makes it unusable in towns. Also (IMO) it would not be wise or safe to do so.
But theoretically as the cruise control would select the most efficient gear to maintain the desired speed I can see that it might improve fuel economy in an auto car but not necessarily in a manual car where it is incapable of influencing the gear selected.
Just thinking - I'm not an expert!
Maybe they've improved recently, but I always found cruise control a damn nuisance. I find it impossible to drive in the UK without touching brake or accelerator, at which point the control switched off.
Modern automatics, with the computer control and a box which is essentially electric, unlike the old Borg Warner type with lots of hydraulics, is every bit as efficient as any manual box. You'd need to be an exceptional driver to pick the perfect combination of speed and gears to match what the computer does
Modern automatics, with the computer control and a box which is essentially electric, unlike the old Borg Warner type with lots of hydraulics, is every bit as efficient as any manual box. You'd need to be an exceptional driver to pick the perfect combination of speed and gears to match what the computer does
Cruise Control, Motorways mainly, regards fuel consumption, that depends on your driving habits, " Not having the car to labour, necessary gear changing, changing at the correct time, Tyre Pressures, Roof bars / racks, head wind, all contribute to excess fuel consumption, the company I used to work for had devices fitted to make sure the HGV changed at the correct time, rev, it did work, it also helped as we were driving tankers.
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