Over the last few weeks, I have got back into the saddle and been cycling to work 2 or 3 times a week.
I have noticed that there is a lot of vehicles on the road nowadays with stop/start. Being a cyclist who stops for red lights (miaow), its very noticeable to hear the amount of vehicles whose engine cuts in when the lights change. A lot more than I would have expected.
Tonight there was a Jaguar XF and on the way in today there was some sort of flatbed truck that seemed to have it.
On a separate note its only when you get on the bike that you really appreciate how gawd awful our road surfaces really are, especially within a metre of the kerb.
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People whose vehicles are overheating sometimes turn the engine off for long pauses in traffic.
In London lately I have noticed some of these stop-start cars which all seem to be diesels, I suppose much in the nature of things. You hear them all churning briefly as the lights change.
Of course modern electronic cars start promptly as a rule. But how many hundreds or even thousands of drivers here, in Japan and the US have so far been appalled and thrown into panic attacks by the failure of anything to happen when they depress the clutch, press the accelerator or whatever their system may be? A good few I would think. Nothing is 100 per cent as any fule kno.
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I prefer to be my own stop start. If I'm three or more cars back and I know the junction has a long red period I'll turn the engine off, if not I won't. I don't trust technology that much.
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Got to wonder about the stop/start tech for the user of the car in it's later life. Surely it takes it's toll on the battery and starter? I've also wondered about modern turbos after a fast run with the previous advice to idle them for a minute or two. Wht does the stop start do when you pull off the motorway into the services?. I'll find out tomorrow as I've got a company BM 328 on the drive for a trip in the morning. Incidentally, fisrt impressions aren't that great. Fast, but no feedback whatsoever from the steering and left in full auto it still finds itself in the wrong gear when you're trying to string bends together. Best dabble with the paddles, in which case I'd simply prefer a manual. A somewhat bland car in my estimation, but a comfy express.
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Stop start systems are the manufacturers way of reducing their products CO2 emissions to meet government introduced targets during laboratory tests. The marketing team then spin it to suggest how "Green" their products are. How much does it reduce fuel consumption in real world driving? Not very much is my guess.
Last edited by: ASBO on Mon 3 Jun 13 at 20:58
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I think we've done this one, and the answer is that stop-start engines have special starters and extra batteries for the purpose. My experiences in one-day loan cars have been very good in a manual diesel Volvo, more than adequate (if occasionally tardy for my nervous liking) in an automatic diesel Mercedes. I'd happily have one full time.
How much does it reduce fuel consumption in real world driving?
I'm acutely aware of how much my auto LEC uses in stop-start traffic: the computer reading will dip from 42 to 35 in a 15 minute jam, and it's been down below 20 in the worst of them. I have no doubt Stop-Start would help there.
And, despite the fear and doubt sown by HJ and sundry others, the roads are not littered with cars whose turbos have failed prematurely or, indeed, at all. The turbo has become another appliance; I doubt anyone here bar the occasional obsessive ever 'simmers' theirs and it won't make the slightest difference if they do.
Last edited by: WillDeBeest on Mon 3 Jun 13 at 21:06
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My V60 has stop/start. It works OK.
My understanding is that there are 2 types of system. The one in the Volvo is the more complex set up whereby you have a separate battery, but some smaller cars have a simpler system with a single battery.
The volvo has quite a list of criteria that have to be met before it stops, so it doesn't stop at every junction. I doubt it really saves much fuel, I'm not sure how much an idling diesel uses, but I doubt its much.
I also think from memory that the urban cycle testing involves a period of idle, so if you have stop start fitted then you are emitting zero emissions for that period of the test
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The one on the X1 was seamless - although it played up due to a fault on the radio (don't ask)
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The stop-start on my car (VW) works well - but only if the cars has warmed up enough to begin with. So it often doesn't do anything to improve my mpg.
But it's not really there to reduce consumption - it's there to reduce emissions (particularly on the official tests) and therefore reduce taxation etc. So even though mine doesn't do much most of the time the fact it's there has reduced the BIK rate by quite a bit :-) The emissions are lower by a good few bands compared to the same car before it got stop-start and regenerative braking (Bluemotion technologies in VW speak).
Last edited by: rtj70 on Mon 3 Jun 13 at 21:38
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...it's not really there to reduce consumption - it's there to reduce emissions...
For a given fuel type, how is one not directly proportional to the other?
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>> I think we've done this one, and the answer is that stop-start engines have ......... extra batteries for the purpose.
2013 Volvo V40s do but as far as I know my 2013 Ford Focus doesn't ~ unless you know different.
Last edited by: L'escargot on Tue 4 Jun 13 at 07:32
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>> >> I think we've done this one, and the answer is that stop-start engines have
>> ......... extra batteries for the purpose.
>>
>> 2013 Volvo V40s do but as far as I know my 2013 Ford Focus doesn't
>> ~ unless you know different.
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The KIAs with start stop have AGM batteries.
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>> The KIAs with start stop have AGM batteries.
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I had to Google for AGM to find out that it means absorbed glass mat. However, I'm still no wiser as to whether they're better than conventional car batteries.
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>> >> The KIAs with start stop have AGM batteries.
>> >>
>>
>> I had to Google for AGM to find out that it means absorbed glass mat.
>> However, I'm still no wiser as to whether they're better than conventional car batteries.
>>
I believe they have a higher capacity and withstand charge / discharge cycles better. beyond that I don't know.
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>>I had to Google for AGM to find out that it means absorbed glass mat. However, I'm still no wiser as to whether they're better than conventional car batteries.
From powercell.co.uk:
The cost of the AGM battery makes it a less attractive choice than the flooded lead acid battery for most every day uses.
The deep cell AGM battery can only be discharged to 50% whereas the flooded lead acid deep cell battery can be discharged to 80%, which means that the flooded lead acid battery will run longer on a single charge.
If an AGM battery is overcharged it will definitely shorten its life and could immediately kill the battery. So extra care must be taken when charging these batteries to ensure they are not overcharged.
Doesn't seem any advantage in cars to me.
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>> The deep cell AGM battery can only be discharged to 50% whereas the flooded
>> lead acid deep cell battery can be discharged to 80%, which means that the flooded
>> lead acid battery will run longer on a single charge.
>> If an AGM battery is overcharged it will definitely shorten its life and could
>> immediately kill the battery. So extra care must be taken when charging these batteries to
>> ensure they are not overcharged.
>>
>> Doesn't seem any advantage in cars to me.
>>
Deep discharge batteries are used for traction power in milk floats and in submarines, also sometimes called "leisure batteries". The batteries used in cars are not the deep discharge type this is one reason why allowing them to totally discharge often kills them.
Some info here -
www.advancedbatterysupplies.co.uk/batteryjargonbuster.html
Last edited by: Old Navy on Tue 4 Jun 13 at 13:42
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>> People whose vehicles are overheating sometimes turn the engine off for long pauses in traffic.
>>
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Not a wise thing to do, and likely to be counterproductive.
The source of heat is still there - very hot cylinder head and engine block - but the means of cooling it has been turned off. No fan, no circulation, no water going through the radiator tubes.
All that will happen is that the engine temperature will rise, and heat penetrate into the inlet system, carburettor, sensors, or whatever, and it may well then be harder to start.
The best short-term recourse if the engine overheats is to turn the heater on full, and keep the engine going at a brisk idle to maintain circulation and a good air flow.
It's only worth switching off if you can leave the engine a couple of hours to cool down properly, or if it gets so hot that the water is boiling out of the filler cap and you have no choice.
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Do modern car fans not continue to rotate when the ignition is switched off when engine is hot?
Certainly used to be the case for older cars?
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It may depend on the car, my Focus was recalled to change the fan from "always live" to "ignition controlled" because a few caught fire while unattended due to corrosion in the fan controller which was vulnerable to salt spray from the road.
Last edited by: Old Navy on Tue 4 Jun 13 at 09:04
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>> Do modern car fans not continue to rotate when the ignition is switched off when
>> engine is hot?
My 2013 Focus does.
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>> >> Do modern car fans not continue to rotate when the ignition is switched off
>> when
>> >> engine is hot?
>>
>> My 2013 Focus does.
>>
But the water pump won't be turning, so the fan will be cooling the radiator but not the engine, which is the bit that matters.
When you restart the engine will be hotter because the high temperature and heat capacity in the cylinder head will have dissipated into the block and coolant standing in the engine.
It's always a disappointment if you notice the temperature gauge climbing ominously, you stop for a few minutes, and then on restarting find that the temperature has soared off the scale. Where's the heat come from? It's still being generated but you have turned off the means of circulating it.
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>> But the water pump won't be turning, so the fan will be cooling the radiator
>> but not the engine, which is the bit that matters.
But manufacturers do it to prevent the heat soak you describe. They are not bothered by heat build up in the radiator, there is still some circulation by convection.
Otherwise why would they build the over run feature in?
Last edited by: VxFan on Tue 4 Jun 13 at 10:16
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>> Do modern car fans not continue to rotate when the ignition is switched off when
>> engine is hot?
Even if they do, the coolant isn't being circulated around the engine, so all that happens is the radiator cools down a bit and the engine remains hot.
(edit just seen Cliff's reply, which basically says the same thing as me)
Last edited by: VxFan on Tue 4 Jun 13 at 10:17
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>> Even if they do, the coolant isn't being circulated around the engine,
>> so all that happens is the radiator cools down a bit and the engine remains hot.
>>
Forcibly cooling the radiator would promote thermosyphonic circulation of the coolant.
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>>Forcibly cooling the radiator would promote thermosyphonic circulation of the coolant.
Not much in a cross-flow radiator. I doubt if you'd get any thermosyphonic cooling on any modern engine installation, although the cooling fan running may blow a bit of air over the engine.
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>> although the cooling fan running may blow a bit of air over the engine.
Which will be hot air from the heat of the radiator.
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After my first three months of start-stop I've come to the conclusion that it's just an annoyance and a nuisance. When the engine stops in traffic I always wonder how well it's going to restart, and when it stops while I get out to open the garage door it's accompanied by lots of beeping. I know I can just disable it, but having to do that is a nuisance in itself. And because VED is a minor part of my motoring expenses, the saving in VED doesn't compensate for all the nuisance. I'd sooner pay a higher VED and not have start-stop. If start-stop had been an optional extra then I wouldn't have specified it.
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>> I'd sooner pay a higher VED and not have start-stop. If start-stop had
>> been an optional extra then I wouldn't have specified it.
>>
Exactly what I did. I used a demonstrator with start stop, soon decided not to have it.
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Whenever I have to drive a car with stop/start, the first thing I do is switching it off.
I like to generate more CO2. They are required for plants to do photosynthesis which in turn provides food for all of us :-)
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If a new car I'm going buy has it, if it can't be turned off - I walk. Simple as that.
I don't mind it in a lot of circumstances, but waiting to pull out into traffic, I do not want the engine stopping if I slip the gearbox into neutral after seeing I can't get out for a few seconds.
The vintage car has a carbon thrust race - so you get into the habit of spending the minimum amount of time with your foot on the clutch. Also in my first car, the bearing type thrust race failed.
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>> I know I can just disable
>> it, ................
........... for one journey at a time. Turning off the ignition resets the start-stop.
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it can be disabled by the use of the appropriate tool through the ODB port. Ask your garage to disable it.
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Depends on the car I guess.
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My new CR-V i-DTEC has stop-start, and it also has keyless ignition. When I had my Accord I used to wait until the glow plug light went out before I started the engine, but with the CR-V the engine starts immediately with a slight push on the start button. It also starts immediately when you push in the clutch pedal when the stop-start is activated. I don't always use it if I know I'm not going to wait a very short time.
I'm also surprised at the fuel consumption of the CR-V. I'm getting 41 mpg on the urban cycle, and the same journeys with the Accord I couldn't better 38 mpg. It will be interesting to see what I get on dual carriage ways and motorways. I used to get around 53 mpg with the Accord. These figures were based on full to full. I didn't have a computer readout on the Accord, but the one on the CR-V tends to underestimate. Last time that I filled up the readout was 37.8 mpg, whereas full to full gave 41 mpg. On my last fill up I got Shell V-Power Nitro, and the trip computer was showing between 45 and 46 mpg. Since I got the CR-V I have eschewed supermarket diesel and stuck to Shell V-Power.
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Robbie
If you don't want to use your s/s, do you just switch it off at the commencement of each journey, and do you have a seperate battery for this function?
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>> Robbie
>> If you don't want to use your s/s, do you just switch it off at
>> the commencement of each journey, and do you have a seperate battery for this function?
No, there is a push button so you can disable it if you wish, so it's on permanently. It works at traffic lights etc. by taking out of gear (obviously) and letting out the clutch. If you don't want to stop the engine you leave your foot on the clutch.
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>> >> Robbie
>> >> If you don't want to use your s/s, do you just switch it off
>> at
>> >> the commencement of each journey, and do you have a seperate battery for this
>> function?
>>
>> No, there is a push button so you can disable it if you wish, so
>> it's on permanently. It works at traffic lights etc. by taking out of gear (obviously)
>> and letting out the clutch. If you don't want to stop the engine you leave
>> your foot on the clutch.
>>
Thanks, Robbie.
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>> Got to wonder about the stop/start tech for the user of the car in its later life.
>> Surely it takes it's toll on the battery and starter?
>>
Minimal, I should think. The battery in the Insignia is enormous, and the starter/generator is a big three phase beastie. Starts within half a second, though I tend to drive it carefully for the first few seconds since I'm not entirely convinced full oil pressure is restored immediately.
You can go for a considerable distance with the engine off in "stop-start" provided you don't exceed 5 mph. Giving the steering wheel a quick nudge restores electrical power steering, and I've never managed to deplete the brake servo. Bigger problem is finding a long enough hill.
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Had it on a car once. It was fitted in a courtesy car supplied by an insurance company.
Hated it and the first thing I did at the start of each journey was to turn the damn thing off.
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>> Minimal, I should think. The battery in the Insignia is enormous, and the starter/generator is
>> a big three phase beastie.
Perhaps its so big and powerful its overloading your Multifunction display and DAB radio? :)
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My car has stop-start technology fitted (part of blue efficiency in MB speak I think) and I have to say I don't give it a second thought. My car is an auto, if that makes any difference, but I certainly couldn't be bothered to deliberately turn it off when I get in the car. I don't recall ever deactivating it.
Would I pay for it? The the blue motion version of our Up! was an extra £300 or so, and and I didn't spec it, thinking that the car would never do a high enough mileage for it to pay back, and saving £30 in road tax wasn't going to make a difference. But actually now when I drive it it seems 'wrong' to hear the sound of the engine when stationary !! So if I was ordering again,yes I probably would, though not to save money, if that makes sense?
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When I have come across stop start I have liked it. If you are getting the benefit of lowered VED you should not be able to turn it off, IMO.
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The Audi A8 is quiet anyway, but when the engine turns off the silence is most welcome.
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Tonight it was the turn of a Porsche Cayenne to save the environment at the traffic lights.....
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>> When I have come across stop start I have liked it. If you are getting
>> the benefit of lowered VED you should not be able to turn it off, IMO.
>>
Well said.
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Do Airbus fit stop-start?
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yes indeed, as demonstrated by BA last week.
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Common practice now to use only one engine for manoeuvring on the ground. Some even use tractors all the way to the runway; not sure how much fuel it saves to introduce another big machine but I'm sure someone's done the sums.
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>> Do Airbus fit stop-start?
>>
Pretty much. Single-engine taxi arrivals and departures are commonplace*, though obviously dependent on weight of aircraft / tight turns / hills / length of taxi etc. If we think we'll be waiting for a long time, we'll taxi to a quiet corner of the airfield and shut down both engines.
* Though preferably not in the sense Zero implied!
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>> >> When I have come across stop start I have liked it. If you are
>> getting
>> >> the benefit of lowered VED you should not be able to turn it off,
>> IMO.
>> >>
>>
>> Well said.
>>
Hmm, it did it's job of squeezing into a lower bracket during the totally artificial EU-mandated standard tests when the model was first put into production. Whether you have it on or off afterwards makes no odds, as the figures obtained in testing are entirely arbitrary and impossible to achieve in real usage either way.
You'd have to be a dyed-in-the-wool eco-nazi to give even the merest hint of a stuff about someone's usage of it.
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>> If you are getting the benefit of lowered VED you should not be able to turn it off, IMO.
Someone would still find a way.
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>> If you are getting the benefit of lowered VED you should not be able
>> to turn it off, IMO.
I would happily pay the higher VED to not have this technology on any car I buy in the future. Fortunately we don't have it on either of our current cars.
Last edited by: andyfr on Wed 5 Jun 13 at 10:22
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>> My car has stop-start technology fitted (part of blue efficiency in MB speak I think)
>> and I have to say I don't give it a second thought. My car is
>> an auto, if that makes any difference, but I certainly couldn't be bothered to deliberately
>> turn it off when I get in the car. I don't recall ever deactivating it.
Is, perchance, your car a company car?
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>>
>> Is, perchance, your car a company car?
>>
Nope, mine is privately funded. For a company car the BMW 520d touring would be the most tax efficient choice I think ;-)
We have some bluemotion Golfs at work as pool cars; I can't imagine anyone deactivates the stop start gubbins, but AFAIk nothing has gone wrong with any of them in the last 30 months.
Last edited by: PeterS on Wed 5 Jun 13 at 18:50
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My Passat CC has 'Bluemotion Technologies' (but is not a Bluemotion model) so has stop-start. It rarely gets to activate on most journeys but when it does works fine. I'd not disable it that's for sure. Either every time or getting someone to do it permanently via the diagnostic port.
There's a new cleaner BMW 518d (detuned engine) that means the old Efficient Dynamics model is no longer in the model line-up apparently.
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Stop Start - Armel Coussine
