Motoring Discussion > Stop / Start technology	Miscellaneous
Thread Author: BobbyG	Replies: 36

Sun 25 Jul 10 13:58   Stop / Start technology - BobbyG

When driving in town it is very noticeable on my trip computer thingy that the fuel economy drops dramatically in stop/start traffic. Would it do more harm than good for me to switch off at traffic lights and hold-ups? Reply to this message | Report message

Sun 25 Jul 10 14:54   Stop / Start technology - Zero

in a diesel, minimum benefit, and much more agro for the DMF. The reason for poor fuel consumption in town is braking and acceleration and gear changes. Reply to this message | Report message

Sun 25 Jul 10 14:59   Stop / Start technology - Iffy

I don't think you will do any harm, but I don't think you will save much fuel, either. As an aside, when I have the top down on the CC3 in traffic, I can hear which cars have stop start technology. Seems to be fitted mostly to BMWs. Reply to this message | Report message

Sun 25 Jul 10 15:14   Stop / Start technology - Old Navy

>> I don't think you will do any harm, but I don't think you will save >> much fuel, either. >> I think the cars with a stop go system have heavy duty starters, alternators, and batteries. If you stop / start the engine of a car that is always used in traffic it must cause wear. When integrated flywheel/alternator/starter systems are used this will be a far more elegant solution to the start stop problem. I don't think you will save much diesel either, you will use it anyway the next time you accelerate. I only stop my engine for holdups that are likely to last for more than 10 minutes. Last edited by: Old Navy on Sun 25 Jul 10 at 15:16 Reply to this message | Report message

Sun 25 Jul 10 15:27   Stop / Start technology - Mike Hannon

You don't honestly believe your trip computer, do you? Reply to this message | Report message

Sun 25 Jul 10 15:36   Stop / Start technology - Old Navy

>> You don't honestly believe your trip computer, do you? >> Mine is remarkably accurate, but then it is a KIA. :-) Reply to this message | Report message

Sun 25 Jul 10 16:03   Stop / Start technology - Bagpuss

In parts of Switzerland you are obliged by law to switch the engine off at red traffic lights. Very impractical in places like Bern or Zurich where there are traffic lights every 10 metres or so (or at least that's how it feels). Reply to this message | Report message

Mon 26 Jul 10 11:50   Stop / Start technology - movilogo

Is stop/start option is available in manual cars only? Reply to this message | Report message

Mon 26 Jul 10 12:10   Stop / Start technology - Bagpuss

BMW presently offer it only in cars with 4 cylinder engines and manual transmission. Apparently they intend to offer it on 6 cylinder engines and automatics in the near future. Reply to this message | Report message

Mon 26 Jul 10 12:35   Stop / Start technology - movilogo

I think it may be bit challenging to do this in autos. For manuals, you need to press clutch to move from standstill, so pressing clutch will restart engine. But in autos, you can press brake while car is on D and just release brake and car will move. Autos can't start unless selector is in P or N. Reply to this message | Report message

Mon 26 Jul 10 12:47   Stop / Start technology - VxFan

>> Is stop/start option is available in manual cars only? The Citroen C3 my father had as a courtesy car had a semi auto box and that had stop/start. That wasn't a true auto box though - it was a manual gearbox with servos operating the clutch. Reply to this message | Report message

Mon 26 Jul 10 15:00   Stop / Start technology - BobbyG

>>You don't honestly believe your trip computer, do you? On my commute my average mpg can sit roughly the same until I reach the stop start and by the time I reach the work, that average can be 1 mpg less than it was at start of journey. I can sit stationary at traffic lights and see it fall by 0.1's while I am sitting there (Ok boring I know but saves being dazzled by the brake lights :) So over a course of a week thats 5mpg knocked off thus the reason for asking! I appreciate Zero's comment that some will be lost in the accelerating / braking as opposed to sitting stationery. Oh, and I have just had my DMF replaced under warranty :) Reply to this message | Report message

Mon 26 Jul 10 15:02   Stop / Start technology - Bellboy

Oh, and I have just had my DMF replaced under warranty > >>>>>>>did they weld it up with 0.6 mig wire or 0.8? ;-) Reply to this message | Report message

Mon 26 Jul 10 12:49   Stop / Start technology - Fursty Ferret

I vaguely remember working out the numbers a few years ago, and for a diesel, you start to make money back after about 10 seconds of being stopped. Diesels start on the first revolution, so starter, alternator, and battery wear is minimal, and my personal opinion is that people who panic about DMF flywheel wear are misinformed. Reply to this message | Report message

Mon 26 Jul 10 13:12   Stop / Start technology - Falkirk Bairn

In 2-3 years time will the Tech issues pages be full of problems with stop/start technology, starter motors that only last 3 yearsi nstead of the life of the car. In 47 years of driving, mostly cars new - 3 years old I have had only 1 starter motor failure - Cavalier - local Indie took it out, popped it into the man 2/3 units up. On top of the cost of the service there was £30 for new bushes and a reconditioned / 2nd hand armature £30. I bet these new hi-tech starter motors are £300+ or is it £500+? Reply to this message | Report message       1

Mon 26 Jul 10 21:38   Stop / Start technology - swiss tony

>> In 2-3 years time will the Tech issues pages be full of problems with stop/start >> technology, starter motors that only last 3 years instead of the life of the car. > Most if not all stop start systems do not use the starter motor to restart the stopped engine, they instead use a starter/generator. I think the more likely problems will be shredded belts, some of which I have already seen on relativity low mileage, but mostly in town used cars.... Belts are normally directional as in the torque is used to turn the alternator, with stop/start the torque is also used to turn over the engine doubling the wear. Reply to this message | Report message

Mon 26 Jul 10 21:43   Stop / Start technology - -

>> Most if not all stop start systems do not use the starter motor to restart >> the stopped engine, they instead use a starter/generator. Never knew that TST, just assumed it would be some sort of high capacity starter. Did i read somewhere that hybrids like Prius stop the engine at it's easiest restarting point, probably my memory playing tricks, if not is Stop Start similarly set up? Reply to this message | Report message

Mon 26 Jul 10 13:38   Stop / Start technology - Zero

>> opinion is that people who panic about DMF flywheel wear are misinformed. do you have a DMF? Reply to this message | Report message

Mon 26 Jul 10 18:59   Stop / Start technology - Fursty Ferret

Yep, it has 120k on it so far. Reply to this message | Report message

Mon 26 Jul 10 13:26   Stop / Start technology - L'escargot

I imagine that stop/start is deleterious to the smooth flow of traffic. Reply to this message | Report message

Mon 26 Jul 10 14:04   Stop / Start technology - WillDeBeest

We're talking about stopping the engine, L'Es, presuming that the car is already stationary. };---) Reply to this message | Report message

Mon 26 Jul 10 18:15   Stop / Start technology - L'escargot

>> We're talking about stopping the engine, L'Es, presuming that the car is already stationary. I'm aware of that. What I meant was that it takes a finite time for an engine to be restarted and if everyone in a stationary queue did it then the overall progress of that queue would be slowed down. It's much the same as when some drivers in a queue at traffic lights don't even think of putting their car into gear until the car in front has actually started moving. Reply to this message | Report message

Mon 26 Jul 10 18:31   Stop / Start technology - Zero

>> when some drivers in a queue at traffic lights don't even think of putting their >> car into gear until the car in front has actually started moving. Whats wrong with that? Reply to this message | Report message

Mon 26 Jul 10 18:55   Stop / Start technology - Old Navy

>> Whats wrong with that? >> Must be in the south east, a nano second's interference with their progress is equivalent to the end of civilisation. Reply to this message | Report message

Mon 26 Jul 10 20:05   Stop / Start technology - Alastairw

I think I have seen this problem in 'inaction' L'es. I was in a queue behind a newish Mini and every time the queue moved the mini paused before puuling away, presumably while waiting for the engine to catch. Most irritating. Reply to this message | Report message

Mon 26 Jul 10 14:18   Stop / Start technology - Auristocrat

My Toyota Auris has stop/start technology. Depending on how heavy the electrical load is, the car will cut out as soon as one comes to a halt and engages neutral. It restarts immediately one depresses the clutch to select first - so there is no real delay in moving off. Where one is using electrical systems (such as the heated rear window or air conditioning), the engine will automatically restart when the system needs charge. Reply to this message | Report message

Mon 26 Jul 10 22:19   Stop / Start technology - MD

Just don't stop. Simples. Reply to this message | Report message

Tue 27 Jul 10 20:07   Stop / Start technology - Zhukov

Can most stop / start systems not just be switched off anyway ? It would drive me nuts to have this kind of system as it seems a very clumsy way to reduce CO2. Working on a laptop or taking a long phone call whilst in a car park or such like during the winter or a hot day will not be a pleasant experience if the engine keeps cutting out. Reply to this message | Report message

Tue 27 Jul 10 20:12   Stop / Start technology - Old Navy

>> Working on a laptop or taking a long phone call whilst in a car park >> or such like during the winter or a hot day will not be a pleasant >> experience if the engine keeps cutting out. >> They can be switched off, but don't work as you describe. The engine stops when you stop in traffic, and starts when you press the clutch to move off. There are many parameters which have to be met for it to work, battery voltage in spec, ambient temperature, engine temperature to name a few. Last edited by: Old Navy on Tue 27 Jul 10 at 20:14 Reply to this message | Report message

Tue 27 Jul 10 20:17   Stop / Start technology - Zhukov

I can find myself sitting parked up in the car for an hour or so each day making phone calls and sending emails. I generally keep the engine running to keep warm or to have the air con on to keep cool. Would a stop / start system not keep turning the engine off ? Reply to this message | Report message

Tue 27 Jul 10 20:18   Stop / Start technology - Old Navy

No. Sorry to be abrupt, distracted. Last edited by: Old Navy on Tue 27 Jul 10 at 20:21 Reply to this message | Report message

Tue 27 Jul 10 20:23   Stop / Start technology - Runfer D'Hills

Planning a route ? Reply to this message | Report message

Tue 27 Jul 10 20:28   Stop / Start technology - Old Navy

>> Planning a route ? >> No, I am a non multitasking male, SWMBO demanded attention, it is dangerous to ignore her. :-) Last edited by: Old Navy on Tue 27 Jul 10 at 20:29 Reply to this message | Report message

Tue 27 Jul 10 20:19   Stop / Start technology - swiss tony

Depends.... Reply to this message | Report message

Tue 27 Jul 10 20:22   Stop / Start technology - Zhukov

"No" "Depends" That clears it up a wee bit :o) Not to worry. Reply to this message | Report message

Tue 27 Jul 10 20:25   Stop / Start technology - Old Navy

I can only speak for my car (although my model does not have it fitted). There are eight parameters which have to be met for it to operate, (these are the ones in the user manual, there may be more). My car would not stop the engine if it was idling in a stationary car. Reply to this message | Report message

Tue 27 Jul 10 20:32   Stop / Start technology - Zhukov

Thank you. The idea of sitting shivering in my car every day just to save the company I work for a few quid a week did not really appeal. Reply to this message | Report message