Stop/start technology

[GFWilliams]

kambites said:

Stopping the engine whilst moving would presumably require a complete rethink of the braking system of most modern cars, because without the engine running you have no servo assistance.

Of course real cars don't have brake servos anyway.

Edited by kambites on Thursday 27th May 13:02

I'd much prefer no servos

When stopped and the engine is off, you can feel that the servos are still working, so I assume they could sort this out...

[LeoZwalf]

There is some serious bks being talked on this thread. I've never driven a car with stop-start but that doesn't mean I'm not qualified to talk about it and bh at the contributors to this thread who didn't engage mind before fingers.

Car makers will have spent many many pounds/Euros/Dollars/Yen etc on developing these systems. This means they will have taken things into account like how much battery power is taken up by several start/stops close togethter. Do you honestly think they'd design it so it would run itself out of juice?

As for those comments about how the system will perform in 5/10/15 years - what on earth makes you think that a 15 year old car with fully electronically controlled fuel injection, ignition timing (yes, I know that's only for the petrol ones) etc etc will struggle to start? A modern engine in decent health shouldn't struggle to start at all even if it were 40 years old. Maybe if the starter motor was buggered then you'll have a problem but that'd be a problem any time you start it, not just with the stop-start.

Grump-mode fully on.

[Dracoro]

So all this stop-starting will place no wear on the starter motor and battery then?...................

Yes, they will have sensors to check that the system can work before using the stop-start. It's handy then that sensors in cars as they get older NEVER break or go faulty.

Some manufacturers will spend a fortune getting the systems "right", TBF BMW are probably one of these. However, do you really place faith in Vaux/Ford/French/Italian manufacturers spending as much time developing the systems? Bean counters trying to drive down costs etc. will mean they don't get the better quality components.

[LeoZwalf]

Dracoro said:

So all this stop-starting will place no wear on the starter motor and battery then?...................

Yes, they will have sensors to check that the system can work before using the stop-start. It's handy then that sensors in cars as they get older NEVER break or go faulty.

Some manufacturers will spend a fortune getting the systems "right", TBF BMW are probably one of these. However, do you really place faith in Vaux/Ford/French/Italian manufacturers spending as much time developing the systems? Bean counters trying to drive down costs etc. will mean they don't get the better quality components.

Sure it will cause more wear on the starter and battery. But do you think that a 5-10-15yr old car is still on its original battery anyway?

you say that sensors in older cars NEVER break or go faulty, I'm guessing that is sarcasm because sure, they do go wrong. But the sensors for the start-stop aren't going to break any more than, say, a coolant temp sensor, or a crank position sensor etc. If a car is well looked after then these things will be replaced when they start to go wrong anyway. I don't really see how start-stop won't work very well on these cars by the time they are 15 yrs old. Surely it will just work in the exact same way it does in 2010 as it will in 2025 on a 2010 car ...?

[rypt]

LeoZwalf said:

Dracoro said:

So all this stop-starting will place no wear on the starter motor and battery then?...................

Yes, they will have sensors to check that the system can work before using the stop-start. It's handy then that sensors in cars as they get older NEVER break or go faulty.

Some manufacturers will spend a fortune getting the systems "right", TBF BMW are probably one of these. However, do you really place faith in Vaux/Ford/French/Italian manufacturers spending as much time developing the systems? Bean counters trying to drive down costs etc. will mean they don't get the better quality components.

Sure it will cause more wear on the starter and battery. But do you think that a 5-10-15yr old car is still on its original battery anyway?

Mine is 10 atm and from what I can tell it is still on original battery, and seems to work just fine

Edited by rypt on Thursday 27th May 14:21

[kambites]

rypt said:

Mine is 10 atm and from what I can tell it is still on original battery, and seems to work just fine

I don't think I've ever replaced a car battery except on my 40 year old MG and that had been left discharged for ages.

[F i F]

LeoZwalf said:

There is some serious bks being talked on this thread. I've never driven a car with stop-start but that doesn't mean I'm not qualified to talk about it and bh at the contributors to this thread who didn't engage mind before fingers.

Car makers will have spent many many pounds/Euros/Dollars/Yen etc on developing these systems. This means they will have taken things into account like how much battery power is taken up by several start/stops close togethter. Do you honestly think they'd design it so it would run itself out of juice?

As for those comments about how the system will perform in 5/10/15 years - what on earth makes you think that a 15 year old car with fully electronically controlled fuel injection, ignition timing (yes, I know that's only for the petrol ones) etc etc will struggle to start? A modern engine in decent health shouldn't struggle to start at all even if it were 40 years old. Maybe if the starter motor was buggered then you'll have a problem but that'd be a problem any time you start it, not just with the stop-start.

Grump-mode fully on.

I think the point people are more concerned about rests on the value of the vehicle 8-10 years down the line versus the cost of replacing a bit of electronickery that we didn't really want nor need in the first place.

I've seen a 6 year old car effectively reduced to scrap value because one piece of electronics was thought to be up the spout.

However you grump about it that does not make any sort of sensible way to go about things.

[mdm123]

kambites said:

Stopping the engine whilst moving would presumably require a complete rethink of the braking system of most modern cars, because without the engine running you have no servo assistance.

Of course real cars don't have brake servos anyway.

Edited by kambites on Thursday 27th May 13:02

my Audi s2 had a hydraulic powered servo with an accumulator built into the system, it would give 50 or 60 pumps of the pedal with the engine turned off before the assistance would stop.

[Deva Link]

kambites said:

The starter motor is just the same as usual though, as far as I know.

I think that's right - except for the system Mercedes use. I had a B Class courtesy car recently and was amazed at how seamlessly stop/start worked, especially the lack of starter motor noise. So I looked it up:

"On the B-Class the stop-start system works almost imperceptibly. As you depress the clutch you find the engine is running even before you realise it with no conventional start-up sound.

And it's all down to the starter-generator which Mercedes fit rather than just relying on the conventional starter motor.

Connected to the crankshaft via the belt drive the starter-generator allows the engine to start much faster and far more quietly than with the conventional starter making it very easy to live with."

[CraigyMc]

kambites said:

I think they usually have higher capacity batteries. The starter motor is just the same as usual though, as far as I know.

Reading some BMW EfficientDynamics* blurb a while back, it mentioned that they had redesigned the starter motor since it would be used more often.

Craigy


ps. Does anyone else look at the BMW "E.D." badge and think "yes.... BMW erectile dysfunction" ?

C

[mattviatura]

I've driven several BMWs with this technology and I think it's a load of crap. I hate having to pander to these green pots of toss.

[F i F]

Must admit I found it a pain at first but have learnt to ignore it. The worst case I have found is when in real stop-start traffic, the sort of thing such as in very bad traffic hold ups as opposed to just busy but still moving urban stuff. Either you never get to rest your clutch foot or it stops all the time just for a few seconds and I eneded up disablingit.

Plus as somebody above said, pandering to ecomentalists just grates.

[ForzaGilles]

I've got stop/start on my new Golf. Seems to work quite well, a little strange at first though. I just can't believe that it saves any fuel though. I would've thought that switching off and restarting an engine uses more fuel than idling for 10/20 seconds?

[Deva Link]

ForzaGilles said:

I've got stop/start on my new Golf. Seems to work quite well, a little strange at first though. I just can't believe that it saves any fuel though. I would've thought that switching off and restarting an engine uses more fuel than idling for 10/20 seconds?

BMW reckon it saves fuel after 2 seconds.

[kambites]

Deva Link said:

BMW reckon it saves fuel after 2 seconds.

Sounds about right. It takes very little to restart a warm engine.

[Elskeggso]

ForzaGilles said:

I've got stop/start on my new Golf. Seems to work quite well, a little strange at first though. I just can't believe that it saves any fuel though. I would've thought that switching off and restarting an engine uses more fuel than idling for 10/20 seconds?

Yeah I was thinking the same.

[Rawwr]

ForzaGilles said:

I would've thought that switching off and restarting an engine uses more fuel than idling for 10/20 seconds?

Maybe true for older engines but I can't believe the effect is anywhere near as bad with modern engines.

[collateral]

When it's cold and you end up in stop-start traffic isn't it possible the car wouldn't get up to temperature? Probably worse on a diesel too

[Dracoro]

collateral said:

When it's cold and you end up in stop-start traffic isn't it possible the car wouldn't get up to temperature? Probably worse on a diesel too

I think it only operates when warm.

[Brewsters]

Someone on here asks if it defaults to being on all time when you start up - yes it does on my 123d - not sure if you can change this through the on board computer - probably not if there is the button on the dash. As I said earlier, I think it's a load of bks, so always turn it off. You pays ya money and takes ya chances. BMW do not offer the option of NOT having it. It's like I'm putting my seatbelt on.... buckle up, turn OFF stop start tomfoolery and off I toodle. Each to their own eh?