In reply to GameboyRMH :
If they were technically and financially feasible, they would be in the cars now. All it would take is one company being brave enough to try it, and show the benefit as well as being reliable enough....
In reply to alfadriver :
Hopefully it won't be too long now:
In a world where new cars are becoming luxury items for the wealthy, the financial feasibility bar should be low enough.
alfadriver said:As for the starter- we are not in the 60's anymore. While starters to break, they don't very often.
From experience owning 6 Honda/Acura products so far beginning in 2001, starters seems to be ~ 120k mile pieces of equipment on that brand of vehicles. With the exception of my latest, none of those have had start/stop on them. I wish I knew how many starts that equates to, but our driving is a reasonable mix of 5-30 mile trips, with a few long vacation type trips thrown in each year. Given this, I disable the start/stop on the current one that I drive every time I start it up to prolong starter life.
Keep in mind that start/stop engines are made with beefier starters to stand up to the increased duty, they also have main bearings with a soft red coating to survive the higher number of start/stop cycles.
In reply to einy (Forum Supporter) :
That seems to be an issue with Honda, not start/stop.
Besides, since start/stop is an emissions device (this is what we are discussing), they are required to be robust to 150k miles, as that is the certified mileage limit. While the OEM coverage is less than that, if enough cars fail before 150k miles (and the limit is really low) then OEM's are forced to recall all of the cars and replace the starter on their bill.
So OEM's all have a vested interest in making sure these make it well past 150k miles before issues.
Agree with the idea that it depends on implementation. I'm fine with it on my Caddy ATS except that as others have said, I do wish it didn't turn the engine back on when shifting from drive to park.
I drove some sort of rental Chrysler minivan and I hated the implementation on that one. Just another couple tenths delay between releasing the brake and the engine coming back on feels like an eternity.
In reply to mfennell :
TIL, thanks! Wish the GR had it.
EDIT: After reading more posts it seems super common to have start/stop with a manual trans, very cool. Just so happens I've somehow never come across it.
alfadriver said:For the test, it's about 1/2 MPG if I remember- most of it in bag 2 of the test which is a lot of stop and go.
[...]WRT emissions, after a little experimenting, the emissions impact is really tiny- so that the SULEV30 and SULEV20 is still possible with start stop operating after every stop on the emissions test.
So I'm reviving this thread to confirm what I think I'm reading here.
I was under the impression that stop/start systems were mostly about reducing emissions, but reading alfadriver's response above seems to imply that it is about fuel economy. From what I take away here, fuel economy improvement is minimal, but also emissions improvement is negligible.
Which raises the question: why have these systems at all?
Or is the second part of alfadriver's comment above only aimed at the instantaneous emissions increase at restart?
The newer cars are getting better with 48 volt mild hybrid systems. Zf has a setup completely built into the transmission like a plug in hybrid that is one of the best i have experienced. At least with bmw's I have seen alot of water pump failures on the system with the alternator/starter belt drive 48 volt system.
einy (Forum Supporter) said:alfadriver said:As for the starter- we are not in the 60's anymore. While starters to break, they don't very often.
From experience owning 6 Honda/Acura products so far beginning in 2001, starters seems to be ~ 120k mile pieces of equipment on that brand of vehicles. With the exception of my latest, none of those have had start/stop on them. I wish I knew how many starts that equates to, but our driving is a reasonable mix of 5-30 mile trips, with a few long vacation type trips thrown in each year. Given this, I disable the start/stop on the current one that I drive every time I start it up to prolong starter life.
Hondas have the worst starters in the industry, at least on the K-series engines. The ones on the "Earth Dreams" 2.0/2.4 don't even last 60k.
In reply to Duke :
The system provides a measurable increase in fuel economy, which was well under $100/mpg (which is the going rate for most companies). That's why it's there.
Measurable and repeatable.
It does impact emissions in a bad way, but it was also figured out how to deal with it. Actually, some of the issues ended up being demonstrations that we didn't fully understand the physics- so fixing this also fixed other things. Meaning this impacted emissions slightly badly, but the net result was a gain due to better understanding what is going on.
I'd say one of the main points of these systems is not for short traffic lights or decel but to stop "gross idling" such as cars sitting outside of schools 20 minutes idling waiting on kids, people sitting in slow drive-thrus for 20+ minutes rather than going inside and getting it in 5 (a Starbucks near me is notorious for this) and the kind of idling cops do. Also "gross idlers" go back to the dealer or call customer service and rage out when their MPG is a lot lower than the sticker since most cars have MPG guages now. So that's why it's kind of stupid that these systems cut off before the car has been stopped 5 seconds or when it kills your air conditioning on a hot day, superheating the interior in seconds.
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