[Jeroen]

Originally Posted by tsk1979

I was merely mentioning the fact that usage of start stop systems would reduce engine life. You could make the engine more "robust", however any engine with start stop system deactivated would have a longer rife.
Not to mention that NO emissions also rise when hot engines are restarted.

There is an endless amount of debate on car forums the world over. But I have yet to see any factual information based on extensive test data that would even give a hint as to what it means for the average car owner.

Modern cars run easily 150-250 K without requiring an engine overhaul. I don't know about India but in most western countries most people will sell their cars long before its ever reached those sort of readings. How much would a start stop system reduce this? I haven't seen facts. Except maybe one sort of data point:
I am in the process of looking at a new company car for my next assignment back in the Netherlands. I have checked with the lease company and they don't charge a higher (full operational) lease price for a start stop equipped car. And they maintain the same max mileage (around 125k).

So if car lease companies, that absolutely thrives on gathering data, don't see an issue, why do the petrol heads see a problem. It's again a case of where there seems to be a lot a generic theoretical debate, but not much practical insights and or data.

We have had cars with start stop system for many years in Europe and they are getting more and more advanced. I personally don't like them. But then again, I rented a car the other day and I did not even notice it at first!

Jeroen

[aditya79india]

Originally Posted by tsk1979

Its called exaggeration. I was merely mentioning the fact that usage of start stop systems would reduce engine life. You could make the engine more "robust", however any engine with start stop system deactivated would have a longer rife.
Not to mention that NO emissions also rise when hot engines are restarted.

There is no reduction in engine life as such. The stress of increased starting cycles essentially comes to the battery, starter motor and the alternator (higher charging requirement). Generally all manufacturers change these 3 parts to higher specs, whenever introducing idle stop feature on their vehicles. Same has happened in Indian market as well. So relax. No need to be apprehensive on engine life. The feature rather saves unnecessary idling.

[Jeroen]

Originally Posted by aditya79india

There is no reduction in engine life as such. The stress of increased starting cycles essentially comes to the battery, starter motor and the alternator (higher charging requirement). Generally all manufacturers change these 3 parts to higher specs, whenever introducing idle stop feature on their vehicles. Same has happened in Indian market as well. So relax. No need to be apprehensive on engine life. The feature rather saves unnecessary idling.

Actually there are other wear and tear factors such as bearings as well, but my personal thoughts is they are exaggerated.
Also the more advanced auto stop system begin to rely on different solutions then just the starter motor and battery

In many hybrids the alternator and starter motor are integrated into one specifically designed for the job at hand
And of course there are engines that start without the use of a starter motor all together.
Jeroen

[tsk1979]

Originally Posted by aditya79india

There is no reduction in engine life as such. The stress of increased starting cycles essentially comes to the battery, starter motor and the alternator (higher charging requirement). Generally all manufacturers change these 3 parts to higher specs, whenever introducing idle stop feature on their vehicles. Same has happened in Indian market as well. So relax. No need to be apprehensive on engine life. The feature rather saves unnecessary idling.

What about NoX emissions. When a hot engine is restarted, NOx emissions are much higher.

[aditya79india]

Originally Posted by tsk1979

What about NoX emissions. When a hot engine is restarted, NOx emissions are much higher.

Most engines these days come with properly tuned EGR systems, directly controlled by the ECU. The ECU knows when the engine is hot!

BTW, NOx emissions are generated when the combustion is happening at high temperature and pressure. That's different from the engine being hot. This criteria may be met even if the engine is cold. Eg. Hard acceleration immediately after an early winter morning start!

Nothing to do with a start stop system.

[Jeroen]

Originally Posted by tsk1979

What about NoX emissions. When a hot engine is restarted, NOx emissions are much higher.

It all depends who you want to believe. Try and google this and you will find a bewildering number of different test results. For both petrol and diesel, for NOx and emissions in general.

I havent read it all, nor would I claim to understand it all. But my impression is that by and large start stop system do have positive effect when it comes to emissions. To put it differently, on average you will get more emission leaving your engine to idle then to stop start. It does depend on many factors though.

Again, I’m not so sure how much benefit you would really see on FE. Its not that easy to quantify or measure unless in a controlled test environment and that is usually not representative for real use cases. And these days we see a lot of rigged test as well, but that is a different matter all together of course.

Personally, I’d say its a very personal choice, like going hybrid or all electric. I don’t think the environment really benefits, although in cities you could probably argue it might have some affect. But on a macro level taking everything into account what it take to produce a car (and batteries) how to generate all that energy needed, i am less then convinced.

Same for this start stop lark. I would say a PR gimmick at best. If you like it and believe in it, go for it.

I stick to my supercharged V8 thank you very much!

Jeroen

[tsk1979]

Originally Posted by Jeroen

It all depends who you want to believe. Try and google this and you will find a bewildering number of different test results. For both petrol and diesel, for NOx and emissions in general.

I actually do not think that you would find any accurate information on google. Its mostly people talking and speculating. Whatever I stated came from mostly conference papers about NOx

But my impression is that by and large start stop system do have positive effect when it comes to emissions.

Diesel engines are CO2 lean as compared to petrol. But when we talk about emissions and particulate they are worse. Even with Start stop you would see FE improvements. There are a few conference papers talking about that. About 6-8% in urban cycle.

Personally, I’d say its a very personal choice, like going hybrid or all electric. I don’t think the environment really benefits, although in cities you could probably argue it might have some affect. But on a macro level taking everything into account what it take to produce a car (and batteries) how to generate all that energy needed, i am less then convinced.

On that I agree. Start stop systems may not put enough dent in pollution in cities. Infact, when it comes to NOx they may be worse.

Same for this start stop lark. I would say a PR gimmick at best. If you like it and believe in it, go for it.

I stick to my supercharged V8 thank you very much!

Jeroen

Well I can't agree with that. A real rig rolls coal

[Jeroen]

Originally Posted by tsk1979

I actually do not think that you would find any accurate information on google. Its mostly people talking and speculating. Whatever I stated came from mostly conference papers about NOx

If you google for the right stuff you will find some of these conference papers. you will certainly find a lot of governmental test data. You will even find some industrial references and test data on start stop system on power generation.

You will also find a lot of crap. The crap, I hate to say, is typically generated by car forums, full of opinions and maybe some individual measure that just don’t hold water as far as I’m concerned. Also, car news sites are notoriously badly informed on this topic.

Originally Posted by tsk1979

Diesel engines are CO2 lean as compared to petrol. But when we talk about emissions and particulate they are worse. Even with Start stop you would see FE improvements. There are a few conference papers talking about that. About 6-8% in urban cycle.

Although the urban cycle might be a reference or base line, it doesn’t reflect my driving style or anybodies for that matter. So I’m not sure how to relate or extrapolate any test results in an urban cycle to my personal situation.

So unless somebody can convince me what my FE gains would be based on these urban cycle they are meaningless statistical data.

Just be slightly altering my driving style I can increase or descrease my FE by far more then 6-8%.

Originally Posted by tsk1979

On that I agree. Start stop systems may not put enough dent in pollution in cities. Infact, when it comes to NOx they may be worse.

maybe, it really depends on the number of start/stops in a give time frame against the otherwise idle time

Originally Posted by tsk1979

Well I can't agree with that. A real rig rolls coal

Good, it seems our biggest difference is around what you can find with google!

Jeroen

[honeybee]

One thing is certain. The start-stop technology has been there in automobiles for decades. If you observe the area near the steering column, you will find a key inserted in a hole. When you turn this key, it can start, or stop, the engine.

Only now, there is no need to turn that key. ;-)