Start-Stop Systems, I'm not convinced

VolvoMan

This technology has been in a lot of mid range cars over the last four years, but have there been any statistics shown in that time which highlight any increased unreliability or acclerated wear of components?

I'm sure it can't be good having a turbocharged petrol or diesel car shutting off so suddenly in congested traffic, especially when it's going to be happeing every few seconds each time the car comes to a standstill.

-Corkie-

VolvoMan wrote: »

This technology has been in a lot of mid range cars over the last four years, but have there been any statistics shown in that time which highlight any increased unreliability or acclerated wear of components?

I'm sure it can't be good having a turbocharged petrol or diesel car shutting off so suddenly in congested traffic, especially when it's going to be happeing every few seconds each time the car comes to a standstill.

They say the turbos have stronger seals etc but only time will tell. I cant see them being reliable in the future.

robbie_998

would really wear out the starter alright.


aswell as that having one of these in a car would actually put me off buying it.

it would wear a lot faster alright and also what if you only stopped for literally 2 seconds and were off again ?

like the odd time if im in seriously bad traffic and i know im not going anywhere for about 5 minuets then i'll knock off the engine cos its a waste but there would have to be a good decent gap between when i knocked the car off and when i turn it back on !

but yeah i dont like this kinda crap to be honest.

i'm all up for reducing fuel costs and saving the environment and all the jazz but this could end up costing you more on maintenance and the likes

Owen

Start stop reduces fuel usage by a miniscule amount. Less than a percent. It's mostly there for show so the manufacturers can have something that owners can actually show people, as opposed to things like plastic wings, undertrays, low rolling resistance tires ...

The starters in cars with the system have been beefed up considerably, and when they were designed they'd have bench tested significantly to last just as long as a normal starter.

Gophur

People should look at how stop-start actually works before deriding the system. It's obvious some of the critics haven't educated themselves on the system.

Oral Surgeon

I disable mine when I get into the car because it wrecks my head cutting on and off....

Plug

They should cut down and costs and use my idea:p
Car runs on 2 cylinders whilst in traffic and ecu divides up the cylinders to use so they wont be wearing down just two cylinders. That way all cylinders will wearing evenly.

si_guru

Gophur wrote: »

People should look at how stop-start actually works before deriding the system. It's obvious some of the critics haven't educated themselves on the system.

Thank you!

The "stop" only happens if you put the car in neutral and lift the clutch, works perfectly on mine.. even has a little benefit - if you nearly stall while trying to crawl in traffic - dipping the clutch (natural reaction) re-starts the car.

Also if the stop/start detects reverse being used so disables itself in car parks etc.

It's been added to get emissions down that's all.

Owen

Plug wrote: »

They should cut down and costs and use my idea:p
Car runs on 2 cylinders whilst in traffic and ecu divides up the cylinders to use so they wont be wearing down just two cylinders. That way all cylinders will wearing evenly.

If they're not igniting a fuel mixture, the cylinders not being used will still be wearing - they'll be connected to the same crankshaft as the ones that are being used.

si_guru

Owen wrote: »

If they're not igniting a fuel mixture, the cylinders not being used will still be wearing - they'll be connected to the same crankshaft as the ones that are being used.

But the Honda Hybrid works like this I believe.

unkel

Plug wrote: »

They should cut down and costs and use my idea:p
Car runs on 2 cylinders whilst in traffic and ecu divides up the cylinders to use so they wont be wearing down just two cylinders. That way all cylinders will wearing evenly.

Not your idea

Cadillac used that idea back in the 70s to let their flagship car run on 4, 6 or all 8 cylinders

Owen

si_guru wrote: »

But the Honda Hybrid works like this I believe.

I'm sure it does, as Unkel said it's been done before, but the cylinders still wear as they're still connected to the crankshaft, and still moving up and down in an otto cycle.

Gophur

Gophur wrote: »

People should look at how stop-start actually works before deriding the system. It's obvious some of the critics haven't educated themselves on the system.

... are you going to explain it for us so, including the benefits?

bazz26

I have it in my car and it is of little or no benefit to me anyway. If I'm stuck in traffic nearly everytime I put the car in neutral and the engine cuts out, Murphy's Law kicks in and traffic starts moving again.

I'm also not convinced that it is good for the turbo or the seals for the engine to cut out when stopped just after coming off say a motorway at 120kph.

Merch

well obviously this has got to be electronically controlled, so would there be a need for the turbo to be running under those conditions anyway? edit or for a car that drives under those conditions regularily to even have a turbo at all ?
I thought , oh this would create a lot of wear on a starter and the inefficiency of shutting on/off instead of just leaving to run.
As far as i am aware the last up stroke of a piston before shutting off (id assume the piston would be alternated to even out wear) the valves stay closed and no fuel is injected or ignition initiated, so a compressed air supply exists that can be used to restart the engine.
I dont think manufacturers do this so they can say their car has it or their car is the most efficient.
They are looking to see what regulations might be applied and are trying to get ahead of the competition early as emission reduction will probably be on the cards, if they stuck with old technology they would be left years behind any competition.
Just like we?I (lots) cant understand why the US managed to keep gas guzzling vehicles compared to Europe/Japan, when the Japanese and Europeans had managed to produce vastly more efficient cars.

US support of their own industry hampered advancement, whereas regulation fostered innovation elsewhere.

To be honset I really think, the problem of gridlock traffic should be solved, so better integrated public transport (ie safe clean and comfortable), and the use of fully electric vehicles (cars and buses) (if they mature enough) as they are much more suited to that kind of driving (90%+ efficient) short distances slowly and in congestion should it exist, compared to 30% approx efficiency for internal combustion engines.

Merch

bazz26 wrote: »

I have it in my car and it is of little or no benefit to me anyway. If I'm stuck in traffic nearly everytime I put the car in neutral and the engine cuts out, Murphy's Law kicks in and traffic starts moving again.

I'm also not convinced that it is good for the turbo or the seals for the engine to cut out when stopped just after coming off say a motorway at 120kph.

certainly any new technology or variation of existing technology may have problems, it may eventually be seen as a motoring evolutionary dead end or a necessary half way house between some other development,
As far as im aware most coolant pumps are engine driven, but I believe Ive heard of a few electric ones (not 100% so dont ask for proof). What I am certain is manufacturers will have determined the cooling requirements and the materials in use as seals (and again there is likely to be problems, Id be surprised if there wasn't before it matures)
certainly what is the case if regulations to limit the harmful effects weren't put in place or regulations that gave unfair advantage (trading tariffs possibly) weren't removed then we would probably still be riding around on horseback or maybe Model T's

Merch

Merch wrote: »

well obviously this has got to be electronically controlled, so would there be a need for the turbo to be running under those conditions anyway?...........

It's the oil that isn't circulating is the (potential) concern

Merch

RoverJames wrote: »

It's the oil that isn't circulating is the (potential) concern

okayy? the oil that isnt circulating? when the engine isnt running, so it doesnt need to? engine stops, so does pump, engine starts so pump turns on?
or do you mean the constant on/off pressure to the oil from the pump being turned on/off with the engine?

I mean there could easily be an accumulator of oil to store pressure to release at each start up, maybe that is something that does exist in current cars? (I havent heard it does now) or will exist, Id hazard a guess any larger engine/vehicle might need such a thing

I'm not trying to take down what you say, Im not 100% what you mean.
If the engine is off it doesnt need lubrication, I can see the oil would still be warm and so viscous so would easily start pumping around the engine again when it re-starts.

I wasn't so open to the technology, until I spoke to some people, that knew more than what i did at the time, (which was that it turns on andf off in traffic , I'm not so quick to shut it down, it may lead to something or like i suggested it may be an motoring evolutionary dead end, or a necessary intermediate step to something else?

edit sorry, i see you mean the turbo re the oil, thought you meant the engine so added this.
Well is there a need for a turbo in certain vehicles, extra component, extra cost
although it can likely help improve efficiency, maybe we need to suit the vehicle to the style of driving better.
As is the case, vehicles are controlled electronically (excluding the driver, and maybe even that will happen, ie exclude the driver ) But the engine will know what the need is to run-down the turbo by electronics, likely turbo wont be needed in those conditions so, engine may remain on while turbo runs/is ramped down?
I'm open to the possibilities, but Id still prefer someone else bought new to trial it before I do

unkel

Merch wrote: »

I dont think manufacturers do this so they can say their car has it or their car is the most efficient.
They are looking to see what regulations might be applied and are trying to get ahead of the competition early as emission reduction will probably be on the cards, if they stuck with old technology they would be left years behind any competition.

+1

In real life this will save very little fuel, but the impact on the standardised test is quite substantial. It's one of the reasons you can now buy a massive 3l 6 cylinder 260BHP engined BMW and only pay €156 motor tax...

@bazz26 - I thought there was a way to switch off the start-stop off?

Seth Brundle

Plug wrote: »

They should cut down and costs and use my idea:p
Car runs on 2 cylinders whilst in traffic and ecu divides up the cylinders to use so they wont be wearing down just two cylinders. That way all cylinders will wearing evenly.

My car uses a similar technology and it seems to work quite well (given the six cylinders). In traffic it only fires on one cylinder.
First it fires on piston #1, then #5 then #3 then 6, 2 and 4.

Merch

I dont think manufacturers do this so they can say their car has it or their car is the most efficient.
They are looking to see what regulations might be applied and are trying to get ahead of the competition early as emission reduction will probably be on the cards, if they stuck with old technology they would be left years behind any competition.

unkel wrote: »

In real life this will save very little fuel, but the impact on the standardised test is quite substantial. It's one of the reasons you can now buy a massive 3l 6 cylinder 260BHP engined BMW and only pay €156 motor tax...

@bazz26 - I thought there was a way to switch off the start-stop off?

While I think they dont do it to say it, no doubt their sales and marketing people will bang on about it, but mainly I think they look and see, if we dont invest in this technology now and x y or z do then we will be left miles behind if the regulations change, its quite feasible to me that large multi billion euro corporations? have people asking themselves those questions, like, will regulations change and where do we need to be in 10 years regarding advancing our technology? not just so they can sell it competitively but also to sell it in europe/US at all. Maybe thats where certain companies might have a sales edge over say future possible imports from China?Malaysia? or maybe Indonesia?
In reality, whatever testing/materials improvement they have done via motorsport routes doesnt really add to their information how that technology reacts in the real world under conditions experienced there, Id imagine they get a lot of feedback about failures through main dealers, (if they aren't they are mad not to) so they need to sell cars with new technology because it appeals to some people about "greening" their driving, even if that may be inaccurate, it may alleviate some guilt.

I think technological advancement like this is a good thing even if I'm niot 100% certain of the outcome, it may be like well do you turn off the light when you leave the room, it depends how long you are gone for (3 secs accodring to mythbusters ??)
I can see the need to either allow the driver to input how the traffic is moving, so maybe fully auto (car detects speed and distance and computes fully auto) or variable control (ie like the variable input to the alternating speed of some wipers, driver suits the specific need s/he feels by some input control that can be adjusted) or fully off.

Having said all that I like driving, dont want the car to be driven for me, but certain features on all cars since the technology existed have to have been automatic, first mechanical control, now electronically.

mech/ hydro-mech float control in carbs, to electronic timing in modern cars.
edit: I should probably really compare mech distributors to electronic timing

pajo1981

unkel wrote: »

Merch wrote: »

I dont think manufacturers do this so they can say their car has it or their car is the most efficient.
They are looking to see what regulations might be applied and are trying to get ahead of the competition early as emission reduction will probably be on the cards, if they stuck with old technology they would be left years behind any competition.

+1

In real life this will save very little fuel, but the impact on the standardised test is quite substantial. It's one of the reasons you can now buy a massive 3l 6 cylinder 260BHP engined BMW and only pay €156 motor tax...

@bazz26 - I thought there was a way to switch off the start-stop off?

1 stop start.is.not available on the 530d
2 tax on the 530d is 430 not 156

Stop start works just fine. The moon bats and gheia worshipers are wrong.

Merch

pajo1981 wrote: »

1 stop start.is.not available on the 530d
2 tax on the 530d is 430 not 156

Stop start works just fine. The moon bats and gheia worshipers are wrong.

Im interested to hear more, Id like to hear some fact that backs up my opinions
I really think any technology only works within certain parameters, so maybe if a person drives with a heavy foot then thinks stop/start will compensate will likely be wrong, and then they may deem stop/start a useless technology when it appears not to work.

By the way, whats a moon bat? or a gheia worshipper for that matter

unkel

pajo1981 wrote: »

1 stop start.is.not available on the 530d

Ah, ok, didn't know that. Makes it all the more impressive that BMW didn't have to resort to start-stop to get a 3l car the size and weight of a previous generation 7-series down to 139g/km CO2

pajo1981 wrote: »

2 tax on the 530d is 430 not 156

Incorrect. The 530d auto* (0-100 in 6.0s, 540NM torque at 1500 rpm) produces 139g/km CO2. That's band B, €156 per year to tax. That's less than a pre '08 1l Yaris / Micra

* The manual does not make it into band B, but only a Vollidiot would buy the manual :pac:

Merch

unkel wrote: »

Ah, ok, didn't know that. Makes it all the more impressive that BMW didn't have to resort to start-stop to get a 3l car the size and weight of a previous generation 7-series down to 139g/km CO2



Incorrect. The 530d auto* (0-100 in 6.0s, 540NM torque at 1500 rpm) produces 139g/km CO2. That's band B, €156 per year to tax. That's less than a pre '08 1l Yaris / Micra

* The manual does not make it into band B, but only a Vollidiot would buy the manual :pac:

Is this a new trend, or has it been going on for some time? an auto is more efficient than a manual?
I haven't looked it up as i dont really like bmw's (mostly because i cant afford one and privately am jealous) but that 7 series 3L BMW is/must be a diesel where previous models wouldnt mostly have been?

pajo1981

unkel wrote: »

pajo1981 wrote: »

1 stop start.is.not available on the 530d

Ah, ok, didn't know that. Makes it all the more impressive that BMW didn't have to resort to start-stop to get a 3l car the size and weight of a previous generation 7-series down to 139g/km CO2

pajo1981 wrote: »

2 tax on the 530d is 430 not 156

Incorrect. The 530d auto* (0-100 in 6.0s, 540NM torque at 1500 rpm) produces 139g/km CO2. That's band B, €156 per year to tax. That's less than a pre '08 1l Yaris / Micra

[SIZE="1"]* The manual does not make it into band B, but only a Vollidiot would buy the manual :pac:[/SIZE]

530d auto puts out 162g per km which puts it in the 430 eur band.

unkel

Merch wrote: »

Is this a new trend, or has it been going on for some time? an auto is more efficient than a manual?

It's been going this direction ever since the introduction of modern tiptronic / steptronic boxes the guts of 20 years ago. But only in high end cars and only certain makes (BMW, Porsche) were leading the way.

But only now are we getting cases where an auto like a 530d (still a tiny bit heavier) is getting better fuel economy than the petrol. And better paper performance as well, but in the real world the performance of an auto has been a lot better than a manual for a long time.

unkel

pajo1981 wrote: »

530d auto puts out 162g per km which puts it in the 430 eur band.

Nope. You're talking about the N57D30O0 engine available since '08 that went first into the F10, but was discontinued earlier this year. The current engine is the N57D30O1. I had to look these engine numbers up

BrianD3

Yes, the CO2 for BMWs keep coming down. The CO2 figures on bmw.ie might need updating. Last time I checked the 520d ED (band A) wasn't on the pricelist whereas it was listed on bmw.co.uk

The latest 535d is in band C and only misses band B by 2 g/km.
The new 4 cylinder 525d is in band B and more powerful than the "old" one which was in band D.
Some of the autos are several g/km better than the manuals.
The CO2 of the petrol engines is down too.

The F10 is out less than 18 months and already there have been improvements. It makes me wonder if this will cause purchases to be delayed in anticipation of more updates and even lower CO2, a kind of downward CO2 spiral.

pajo1981

unkel wrote: »

pajo1981 wrote: »

530d auto puts out 162g per km which puts it in the 430 eur band.

Nope. You're talking about the N57D30O0 engine available since '08 that went first into the F10, but was discontinued earlier this year. The current engine is the N57D30O1. I had to look these engine numbers up

i didnt even have to read this post. once guys start.quoting engine numbers i just flee the thread.

unkel

pajo1981 wrote: »

i didnt even have to read this post. once guys start.quoting engine numbers i just flee the thread.

So you keep telling me I was wrong and after I go through the trouble of finding backup and proof online that I was right, you just feck off? That's pretty ignorant, dude.

pajo1981

unkel wrote: »

pajo1981 wrote: »

i didnt even have to read this post. once guys start.quoting engine numbers i just flee the thread.

So you keep telling me I was wrong and after I go through the trouble of finding backup and proof online that I was right, you just feck off? That's pretty ignorant, dude.

Ah unkel. sure i was only trying to be funny.

Of course i read your posts.

i spotted the engine codes and thought **** ive ****ed with the wrong dude.

VolvoMan

BrianD3 wrote: »

The F10 is out less than 18 months and already there have been improvements. It makes me wonder if this will cause purchases to be delayed in anticipation of more updates and even lower CO2, a kind of downward CO2 spiral.

We are also seeing the return of the 520i (four cylinder) with the latest round of updates. It is a full six grand more than the 520d though, so I'm surprised they're even offering it.

unkel

pajo1981 wrote: »

Of course i read your posts.

i spotted the engine codes and thought **** ive ****ed with the wrong dude.

LOL, fair enough

unkel

VolvoMan wrote: »

We are also seeing the return of the 520i (four cylinder) with the latest round of updates. It is a full six grand more than the 520d though, so I'm surprised they're even offering it.

Good point. Remember Subaru withdrew all of their petrol cars from the Irish market once they had their first ever diesel engine out there.

VolvoMan

unkel wrote: »

Good point. Remember Subaru withdrew all of their petrol cars from the Irish market once they had their first ever diesel engine out there.

Out of interest, I checked the performance statistics for the F10 520i compared to the E39/E60. While today's model has two cylinders less than those cars, it still has an extra 14bhp and 54 lb ft of torque. It really shows how far the game has moved on in just a little over ten years.

Edit: I just found out that this new model is in fact turbocharged, making the quoted figures appear merely average more than anything.

R.O.R

Along with the Passat (which has had start/stop for a while), the most popular Mondeo engine now has start stop, and for MY2012, the Insignia gets start/stop to bring it in to band A.

With that amount of rep mobiles on the road, I'm sure we'll here quite soon if there are issues.

Haven't heard of any problems directly associated with the start/stop, only the BMW petrol problems that only effects the ED versions.

Bigus

Properly engineered stop start systems involve a lot more than a few microswitches to turn off the engine and restart it on the clutch.

Apart from a beefier starter motor , some manufactures have switched to electric water pumps, oil pumps and electric power steering. (Roverjames the electric oil pump overcomes hot turbo circulation problems)

Electric coolant pumps ensure the interior heating will still work with the engine off also.

There are other efficiency gains from electric pumps such as not using any energy to circulate coolant while the engine is cold.( I know a thermostat does this in older engines but a thermostat won't stop a water pump using energy unnecessarily)

Furthermore the energy to electrically drive these systems is harvested on the overrun, commonly referred to by manufacturers , as brake energy regeneration.

In fact the only cars to genuinely have proper brake energy regeneration are the hybrids with a second large capacity high voltage battery fed by actual generators which provide braking force when engaged by pushing the brake pedal before the discs come into play for heavier or sudden braking.

I think the best example of stop start is in the Prius because a conventional starter is not used. Instead a heavy fly wheel is spinning all the time and this is used to restart the combustion engine just like dropping the clutch in a stalled manual car at say 40mph in fifth gear. (engine restart is effectively imperceptible) Therfore the prius engine is constantly turing on and off without the driver being aware ,except at standstill.

Mazda's new idea of stopping a piston at the top of a compression stroke and firing a spark to restart the engine instead of a starter is probably the best idea for non hybrid cars.

Walk past a line of traffic stuck at lights and imagine in a few short years time there will be silence instead of twenty engines ticking over totally unnecessarily.

Having any engine off for even a few seconds is going to ad up to less fuel used , less wear and even works well on my old V8 having learned lessons from a hybrid.

ShadowHearth

Interesting debate.

When I sow those start stop things in high power V8 V10 super cars it sort of made sence. Sort of... If I cam afford to buy a super car I won't give two ****s about mpg and enviroment.

Then they started putting that in to 1.6 diesels.... Oh lord...

I would be more old school fella, who like things less complicated and be more reliable. On the tower of unrialibity of modern cars, they puted this new system.

How do they count co2 then lads? If this system let's to put down emissions for tax? I presume some Weird average?

Henry Ford III

My car has start/stop. Seems to work well.

Thing is in city conditions where you might move 10 yards and then stop for 15 seconds, it's probably better to disable the system.

si_guru

Henry Ford III wrote: »

My car has start/stop. Seems to work well.

Thing is in city conditions where you might move 10 yards and then stop for 15 seconds, it's probably better to disable the system.

You don't have to disable it though - just not declutch in neutral right?

Henry Ford III

si_guru wrote: »

You don't have to disable it though - just not declutch in neutral right?

Yep. I've a habit (for right or wrong) of putting it in neutral, handbrake on, and taking my foot off the clutch.

Reloc8

si_guru wrote: »

Thank you!
f you nearly stall while trying to crawl in traffic - dipping the clutch (natural reaction) re-starts the car.

But...as with my car...the start-stop is engaged only in neutral...you wouldn't be in neutral while trying to crawl in traffic so its irrelevant...and you can't stall while you're in neutral.

If you nearly stall, declutching will recover you anyway.

Anyway, the start stop on my car doesn't kick in every time I nudge forward in a traffic jam. I don't know exactly what the parameters are, but basically after it has cut in and then restarted, I have to get up a little speed before it will auto cut out again. More or less getting it into second gear seems to do it.

As was mentioned, its an anti-emissions measure.

There are stories that on petrol engine BMW's they eat your ignition coils.

Bigus

Bigus wrote: »

............
Apart from a beefier starter motor , some manufactures have switched to electric water pumps, oil pumps and electric power steering. (Roverjames the electric oil pump overcomes hot turbo circulation problems) ..........

That would make perfect sense
What manufacturer has stop/start on a turbo equipped car with the electric oil pump though?

corktina

arent you afraid that one day you'll go to pull off and it wont restart? Murphys Law says this will be in the middle of the bigest junction for miles.

The Guvnor

Was in a new model Touareg recently and it had the bluemotion (IIRC) anyway when the car say comes to a junction or traffic light and the driver comes to a full stop engine cuts out - as soon as you hit the accelerator it starts up again.

All the time the car was in D.

Not sure I am a fan tbh - if it helps with fuel to a large % super but if it is a 1-2% amount hardly worth it imo.

Have to say it is disconcerting when it konks out so to speak.

It works fine but it is different! :-)

bazz26

unkel wrote: »

+1

In real life this will save very little fuel, but the impact on the standardised test is quite substantial. It's one of the reasons you can now buy a massive 3l 6 cylinder 260BHP engined BMW and only pay €156 motor tax...

@bazz26 - I thought there was a way to switch off the start-stop off?

There is but by default the system is enabled. So you have to hit the button to switch it off everytime you get into the car.