I will never buy a new Holden again "ever"

[Tezza's ZB]

The reviews of the stop start on the Commodore .. speaking about the LT anyway, they’re outstanding. The comment was, ‘ you are virtually completely unaware that the engine has stopped and restarted’..I fully agree, and better than any car I have driven.The economy or environmental benefits are another discussion, suffice to say they are of little consequence. It’s so good I haven’t turned it off.

I didn’t come down in the last shower, so I am aware of your game. I did though have another quick look just for you; the word ‘economy’ should read ‘economic’.

 

[Skylarking]

...What happens is that the ECU stops the engine with one cylinder charged, just after TDC - so all it needs to do is fire a spark into the cylinder, that ignites the charge, shoots the piston down and the rest follow - really clever idea TBH...

Yes very clever as the system needs smarts to know which cylinder is in such a state so it can fire the appropriate plug. Mazda uses such a system with stater assistance but not sure how other makers do it... some are still old school and simply go the big battery and starter approach.

 

[Tezza's ZB]

I was fundamentally talking about how good or bad the on/off engine start is on the ZB. I realise the benefits, but people on this forum and in the general community have said they have turned it off because it bothered them a lot. I haven’t turned mine off as I said, so I’m a good boy.
I won’t comment further on this, not playing a game.
Maybe I’ll talk about electric cars, but I’ll need another thread won’t I, oh, ‘thread’, have I got the right terminology?

 

[Tezza's ZB]

Stop/Start has been around for a very long time, before being integrated in vehicles systems.

First saw it overseas many decades ago. It was used on a very congested roads that resembled car parks during the rush hours. A road sign would indicate you must switch off your engine if stationary for more than a minute. And they did fine people who didn’t follow the rules and switch off.

The intent was to stop exhaust fumes being pumped into the local area while the cars just sat there idling and not moving. According to the locals who lived on such roads, they swear it made a huge difference to air quality.

well go on them eh, and good on you too for such insights

 

[arsevee]

Yes very clever as the system needs smarts to know which cylinder is in such a state so it can fire the appropriate plug. Mazda uses such a system with stater assistance but not sure how other makers do it... some are still old school and simply go the big battery and starter approach.

On the ECU-governed systems they tend to pick one cylinder to use every time - cylinder one is a common pick (though I have no idea why, there's probably a valid engineering reason); this use of a single-cylinder to restart also accounts for the 'jerkiness' of the restart on some manufacturer's implementations, but the LGX is particularly well done...

Speaking of Mazda - their development of their SkyActive programme is pretty clever - nothing to do with start-stop, but interesting nonetheless:

 

[figjam]

What happens is that the ECU stops the engine with one cylinder charged, just after TDC - so all it needs to do is fire a spark into the cylinder, that ignites the charge, shoots the piston down and the rest follow - really clever idea TBH...

Thanks for that explanation, very simple to understand.

I have done some google exploring about the subject in the last few hours ……. stuff written by experts who should know, and those who think they know. None were as concise and to the point as your comment.

It seems that some systems are battery/starter motor activated, some are cylinder activated, and some ‘assisted’, being both.
The main ‘problems’ mentioned are the drain on the battery while the engine is stopped, (lights, aircon), and the effect of lubrication to moving parts being interrupted for continuous brief periods. How this affects the longevity of electrical and mechanical components is a debateable point.

Let’s say that an engine idling in a stationary car is 1 litre per hour, and you are delayed at the lights for 3 minutes, that is usage of 50ml and less than 10 cents. (my maths OK ?) For you poor souls who live in a large city, and are stuck for an hour going not far with thousands of other poor souls, the big picture can add up and be justified. But, then the acceleration in the traffic light grand prix would kill any savings.

But for us country bumpkins, not necessary, not needed.

 

[Skylarking]

^ yeah, stop start is much less useful in the country and the system would have little reason to activate and shut the engine down. City folks have a problem country folks don’t have.

@arsevee not at all sure how a stop start system could ensure the engine stops with cylinder #1 primed and ready to fire each and every time. Maybe such systems just happen to find cylinder #1 is the most often primed based on timing of shutdown but i can’t see how it’s something that can be guaranteed (so system must cope with choosing appropriate cylinder). Insights welcome

And I was referring to Mazda i-stop stop/start system which at 0.35 seconds is the fastest system around (according to wiki). However, even at 0.35 seconds, most people could detect the pause between pressing accelerator and expected result (but easy to live with).

I think it’s smart tech... especially for city folks living next t9 busy congested roads.

@Tezza's ZB no idea what you are trying to say... maybe some long proof reading before you post would be useful (or a long drive in your beloved ZB).

 

[arsevee]

@arsevee not at all sure how a stop start system could ensure the engine stops with cylinder #1 primed and ready to fire each and every time. Maybe such systems just happen to find cylinder #1 is the most often primed based on timing of shutdown but i can’t see how it’s something that can be guaranteed (so system must cope with choosing appropriate cylinder). Insights welcome

I'm not an automotive engineer, but the ECU will know where cylinder is due to the crank position sensor(s) and will know whether each cylinder is sucking, squeezing, banging or blowing, so could brake the engine at the right spot... Even if it's a 'random' cylinder selection, it would still work ok

 

[Skylarking]

... the ECU will know where cylinder is due to the crank position sensor(s) and will know whether each cylinder is sucking, squeezing, banging or blowing, so could brake the engine at the right spot... Even if it's a 'random' cylinder selection, it would still work ok

Yeah, I understand ECU knowing cylinder position and what not, just not how it could brake the engine to ensure it’s in the correct/desired spot. Regardless, it works and it’s neat.

Thanks for the explanation

 

[Tezza's ZB]

0

^ yeah, stop start is much less useful in the country and the system would have little reason to activate and shut the engine down. City folks have a problem country folks don’t have.

@arsevee not at all sure how a stop start system could ensure the engine stops with cylinder #1 primed and ready to fire each and every time. Maybe such systems just happen to find cylinder #1 is the most often primed based on timing of shutdown but i can’t see how it’s something that can be guaranteed (so system must cope with choosing appropriate cylinder). Insights welcome

And I was referring to Mazda i-stop stop/start system which at 0.35 seconds is the fastest system around (according to wiki). However, even at 0.35 seconds, most people could detect the pause between pressing accelerator and expected result (but easy to live with).

I think it’s smart tech... especially for city folks living next t9 busy congested roads.

@Tezza's ZB no idea what you are trying to say... maybe some long proof reading before you post would be useful (or a long drive in your beloved ZB).

you're still troubled by

Not sure what is being said here. Must be my comprehension skills lacking - I don't want to be confrontational.

youre right it is your poor comprehension skills.. and a wimpy attempt to post anything of substance