Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: astroblaster on 04 May 2011, 01:48:59

Title: cruise control
Post by: astroblaster on 04 May 2011, 01:48:59
Hi will i use more fuel using the cruise control rather than the old right foot on motorways etc
Title: Re: cruise control
Post by: Jimbob on 04 May 2011, 06:40:37
very little in it....

but yes, you CAN drive more economically without cruise...

imho, most people dont, so cruise helps, I use it as a speed limiter  :y
Title: Re: cruise control
Post by: TheBoy on 04 May 2011, 07:54:10
Sticking (religiously) to a speed manually is more economical than cruise, esp on the non DBW engines.

Title: Re: cruise control
Post by: jimac on 04 May 2011, 08:42:13
Sticking to a speed manually for any length of time is virtually impossible and you'll probably overcompensate as your speed changes.  Cruise will hold a pretty much constant speed using tiny changes to the throttle as necessary - neither too much or too little.  So, cruise will use less fuel for a given speed than you can keep manually.

However, sticking (religously) to a throttle position will use less fuel but your speed will vary widely.
Title: Re: cruise control
Post by: 2woody on 04 May 2011, 08:46:50
last time I experimented with this, I was able to use half the fuel when not using cruise control, but that was resorting to some pretty extreme measures.

I find that when not using cruise, I don't have any trouble keeping the speed within three or four miles per hour anyway, so fuel use is naturally less than with the cruise enabled, where the "constantly adjusting throttle" certainly hurts fuel economy.

Cruise, where I use it is only to prevent right foot pain on long journeys
Title: Re: cruise control
Post by: TheBoy on 04 May 2011, 08:51:10
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last time I experimented with this, I was able to use half the fuel when not using cruise control, but that was resorting to some pretty extreme measures.

I find that when not using cruise, I don't have any trouble keeping the speed within three or four miles per hour anyway, so fuel use is naturally less than with the cruise enabled, where the "constantly adjusting throttle" certainly hurts fuel economy.

Cruise, where I use it is only to prevent right foot pain on long journeys
That is my experience and view technically.  I think the DBW cruise is a bit better, though, but still not as good as Mk1 brain.

I tend to use it more through those 50mph average speed traps on motorways, or long 30mph villages
Title: Re: cruise control
Post by: Chris_H on 04 May 2011, 09:18:57
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last time I experimented with this, I was able to use half the fuel when not using cruise control, but that was resorting to some pretty extreme measures.

I find that when not using cruise, I don't have any trouble keeping the speed within three or four miles per hour anyway, so fuel use is naturally less than with the cruise enabled, where the "constantly adjusting throttle" certainly hurts fuel economy.

Cruise, where I use it is only to prevent right foot pain on long journeys
That is my experience and view technically.  I think the DBW cruise is a bit better, though, but still not as good as Mk1 brain.

I tend to use it more through those 50mph average speed traps on motorways, or long 30mph villages
I would agree that brain will use less fuel due to the ability to read the terrain ahead and pre-empt gradients/hazards.

I use it only to limit my speed but it's important not to override it for long periods.  By which I mean if you manually accelerate past the set cruise speed, it's important to cancel it as having it come back in when you've forgotten it's on and are slowing for a hazard etc. can be more than disturbing!

The book doesn't recommend it for low speeds IIRC, and I think 25mph is the slowest it will engage?
Title: Re: cruise control
Post by: jimac on 04 May 2011, 09:24:00
Well, my experience is that using cruise will generally be more economical for maintaining a steady speed than trying to do it manually.  Admittedly, I don't have experience with cruise on the Omega (I haven't had it enabled yet) but my previous 4 cars (a Volvo V40, Jeep Grand Cherokee Auto and 2 Jaguar 2.5 V6 X-Type Autos) all had cruise and cruise would definitely improve mpg by 3-4 over a longish distance compared with not using it.

I think the important element here is the "given speed".  When controlling manually speed will rise and fall due to the road surface, hills, bends and even just lack of concentration.  I find that my speed will often creep up beyond my target, or fall behind it, maybe just because I fall in line with other traffic or the road becomes clear - especially over long distances (>100 miles).  Adjusting speed manually will always use more fuel than letting the computer take control because my foot is less subtle than the cruise.

But, as they often say, Your Mileage May Vary.

Jim.
Title: Re: cruise control
Post by: TheBoy on 04 May 2011, 09:34:11
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last time I experimented with this, I was able to use half the fuel when not using cruise control, but that was resorting to some pretty extreme measures.

I find that when not using cruise, I don't have any trouble keeping the speed within three or four miles per hour anyway, so fuel use is naturally less than with the cruise enabled, where the "constantly adjusting throttle" certainly hurts fuel economy.

Cruise, where I use it is only to prevent right foot pain on long journeys
That is my experience and view technically.  I think the DBW cruise is a bit better, though, but still not as good as Mk1 brain.

I tend to use it more through those 50mph average speed traps on motorways, or long 30mph villages
I would agree that brain will use less fuel due to the ability to read the terrain ahead and pre-empt gradients/hazards.

I use it only to limit my speed but it's important not to override it for long periods.  By which I mean if you manually accelerate past the set cruise speed, it's important to cancel it as having it come back in when you've forgotten it's on and are slowing for a hazard etc. can be more than disturbing!

The book doesn't recommend it for low speeds IIRC, and I think 25mph is the slowest it will engage?
19mph
Title: Re: cruise control
Post by: bigdods on 04 May 2011, 14:38:30
IME my consumption is a lot better when using cruise, but I do spend 90% of my time wandering around the motorway network.

Having said that, i know I can get better efficiency by driving with Cruise off, but what normally happens is my speed gradually creeps up with the tempation to stay with the traffic flow so economy goes down. On cruise I pick my speed then choose the lane that suits it rather than trying to keep up with the faster cars in lane 3.

I have averaged 33mpg over the last 2 years (including some periods when I have driven it like its stolen !) but recently recorded a personal best of 38mpg over a 200 mile run in light traffic with cruise set to 60 as I was actally early for once so needed to waste some time.
Title: Re: cruise control
Post by: Nick W on 04 May 2011, 17:56:36
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Well, my experience is that using cruise will generally be more economical for maintaining a steady speed than trying to do it manually.  Admittedly, I don't have experience with cruise on the Omega (I haven't had it enabled yet) but my previous 4 cars (a Volvo V40, Jeep Grand Cherokee Auto and 2 Jaguar 2.5 V6 X-Type Autos) all had cruise and cruise would definitely improve mpg by 3-4 over a longish distance compared with not using it.

I think the important element here is the "given speed".  When controlling manually speed will rise and fall due to the road surface, hills, bends and even just lack of concentration.  I find that my speed will often creep up beyond my target, or fall behind it, maybe just because I fall in line with other traffic or the road becomes clear - especially over long distances (>100 miles).  Adjusting speed manually will always use more fuel than letting the computer take control because my foot is less subtle than the cruise.

But, as they often say, Your Mileage May Vary.

Jim.
 

Either there's something wrong with my cruise control, or your foot if you think the cruise control is more subtle than your foot! The advantage you have without the cruise control is that you can plan ahead; the control can't/doesn't, and is a  lot more abrupt. Which is what makes it unusable in traffic.

I find that my 3.0l auto estate now averages just over 30mpg at motorway speeds with no attempt to drive economically. That's mostly 90mph cruise speed with cruise on where possible.
Title: Re: cruise control
Post by: Omega Man on 04 May 2011, 20:14:12
I agree cruise is great for 50 limits etc. but mine gets all exicted if there is a steep hill and changes down to race up it ;D I have to knock it off on hills so it doesnt get carried away ;)
Title: Re: cruise control
Post by: astroblaster on 05 May 2011, 01:04:57
Thanx very much for your replys think i will stick to the old right foot for now :y
Title: Re: cruise control
Post by: jimac on 05 May 2011, 08:51:42
As I said, I haven't used the Omega cruise yet and I'm beginning to wonder if it's worth enabling it as it sounds a bit crude.  I have never had any of the problems mentioned on here with cruise in my previous cars, or even my bike.  I just set the speed and let the car get on with it; no jumping through gears or surging, just a steady speed maintained.
Title: Re: cruise control
Post by: TheBoy on 05 May 2011, 08:59:14
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As I said, I haven't used the Omega cruise yet and I'm beginning to wonder if it's worth enabling it as it sounds a bit crude.  I have never had any of the problems mentioned on here with cruise in my previous cars, or even my bike.  I just set the speed and let the car get on with it; no jumping through gears or surging, just a steady speed maintained.
The DBW is mmore refined than the seperate actuator, but all cruise units ultimately 'lift off' and 'power on' continuously to maintain their speed.
Title: Re: cruise control
Post by: Chris_H on 05 May 2011, 09:03:10
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As I said, I haven't used the Omega cruise yet and I'm beginning to wonder if it's worth enabling it as it sounds a bit crude.  I have never had any of the problems mentioned on here with cruise in my previous cars, or even my bike.  I just set the speed and let the car get on with it; no jumping through gears or surging, just a steady speed maintained.
I wouldn't say it was any worse than most.  It's the general principle of responding to inlet manifold pressure or road speed that is inappropriate.  A gradient of the wrong angle and length will cause the system to increase throttle at a point where a driver would be backing it off.  Likewise mid-bend, a sensible driver would not normally stab the throttle at this point.

And some more sophisticated systems are worse! I think I've recounted on here before about a friend's Mondeo with adaptive cruise control.  He can set it to 60 on a country road and it drives up behind a car doing 40 so it slows to maintain a gap.  Car in front goes round a bend and the system loses sight of it.  You can probably guess the rest!  Car tries to get back to 60 and suddenly "finds" the car after the bend is completed, so it has to brake.

No. the Omega's system isn't all that bad really. ;D