This video explains it well youtu.be/qu8cJ2t_ja8
Basically the engine experiences the most wear when starting, because it doesn’t yet have oil pressure. That takes around 7 seconds with the engine featured in the video.
Comment on Kia drops the ball again on their vehicles
FishFace@lemmy.world 1 day agoWhy will stop-start cause additional engine wear? It’s literally off. It only kicks in when the engine, and hence engine oil, is warm, so there should be no extra wear caused by starting.
The fuel savings can be significant, but more significant is the reduced emissions. I guess you don’t care about that though. Fuck all the children breathing in the polluted air, right?
Zeko9381@lemmy.world 1 day ago
FishFace@lemmy.world 1 day ago
Typically it experiences most wear at start because the oil isn’t up to temperature. When stopped at a red light, oil is still coating all the components, so while the pressure may be low, it will only be a momentary increase in wear. 7 seconds is very little compared to the time it takes the engine to get up to temperature on a cold morning, which is wear the majority of wear will still come from.
These systems have been in common use for like 15 years or something, and first became commercially available over 25 years ago. We’d have actual hard evidence if it were causing excess wear.
Lemmyoutofhere@lemmy.ca 17 hours ago
That’s only on a cold start.
Sonotsugipaa@lemmy.dbzer0.com 1 day ago
As far as I’ve read around, S&S mainly wears out the starter.
I don’t understand how the system could cause problems on slippery roads, but if it works on OP’s car like it does in mine, the way it’s designed to kick in is dumb, infuriating and counterproductive.
I have to disable it every time I start the car, because otherwise it would just stop the engine and restart it immediately whenever I get to a stop sign (which burns more fuel than just staying on).
BUT, if I want S&S to work, I need to re-enable it BEFORE I slow down, otherwise it just doesn’t - but I can’t predict how long I have to wait when I stop before I get to the sign, if I could they wouldn’t have put a stop sign there in the first place!
So I either:
And my car isn’t even a KIA, I can’t imagine how bad the S&S system would be on a KIA!
Lemmyoutofhere@lemmy.ca 17 hours ago
You know you are actually supposed to come to a full stop at stop signs right?
Sonotsugipaa@lemmy.dbzer0.com 17 hours ago
You know I’m talking about the Start & Stop system and not the Keep Rolling Slowly & Stop, right?
FishFace@lemmy.world 1 day ago
Engines with start-stop have beefier starter motors. Electric motors can be sized for basically any task - the motors in my EV are not going to wear out and their duty cycle is crazy compared to a starter motor! So it’s just a matter of cost and size.
Sounds insane to require drivers to disable start-stop to pass a test - where’s that? You mention stop signs so that sounds like the US. I’m afraid I don’t really trust US driving tests to accomplish anything sensible…
Sonotsugipaa@lemmy.dbzer0.com 22 hours ago
Wait hold on… why’s that? Is there any juristiction where there are traffic laws, but no stop signs?
FishFace@lemmy.world 22 hours ago
Stop signs are not a big part of driving in some countries. I obviously don’t know about everywhere, but in other countries I’m familiar with (Europe), most USA “stop” junctions are give way/priority/yield junctions where you don’t have to come to a complete stop, so stop-start would have no impact.
In the UK, you only get Stop signs on junctions where your view is so extremely limited that anything less than a stop or absolute dead crawl would just always be dangerous. They’re very rare. In comparison, Yield signs in the USA are comparitively rare (in my experience) and most junctions where you most yield priority are governed by Stop signs.
Sonotsugipaa@lemmy.dbzer0.com 22 hours ago
This is in Italy, it IS insane, and admittedly I don’t know how much my grievances against S&S are mitigated by automatic transmissions (never used in tests).
Tests do not require you to disable S&S, instructors simply tell you not to let out the clutch while in neutral to avoid it, but the strictest examiners see engine shutdowns as “failure to correctly operate the vehicle”, like stalling - if it happens once, we all make mistakes, if it happens twice, come on man, if it happens three times k gg bb, it doesn’t matter whether it’s a feature of the car.
Most of the people who turn S&S off do so because they find it annoying, I myself try to use it effectively but I prefer driving responsibly rather than playing chess with a half-metric-ton deadly weapon.
There are arguments that having your engine off on the road is unsafe, I guess those examiners are just being zealous? If they even exist, I’m trusting my instructor’s tales on this factoid, but drivers’ ed here is very strict so I’m inclined to believe him.
I do know that S&S systems require better starters, but that just means they cost more, right? And even if the increased cost is marginal, the increased fuel consumption on short stops is still a problem.
FishFace@lemmy.world 22 hours ago
I see. That sounds very over-zealous to me, yes. The delay in moving off is so small that it doesn’t really have a safety impact (and the idea that a delay in moving off is a safety issue is way overblown in general, because the occasions when it comes up are so rare compared to the occasions when adequate braking comes up.).
The beefier motors do cost more, and I haven’t seen a cost comparison. I would imagine they don’t cost much more though, and soon pay for themselves if you’re driving in the city. And they won’t overall increase fuel consumption - that much is clear from measurements. A random reddit post claimed that the break-even point in stop-start is a mere 7 seconds, which is basically every red light. Idk if that’s reliable but it gives you something to consider.