Reply
Thread Tools Display Modes
#51
Old 05-19-2018, 07:30 PM
Guest
Join Date: Feb 2017
Posts: 2,453
Quote:
Originally Posted by Capn Carl View Post
This thread has a similar character to other threads on a variety of forums, regarding new technologies. Ten or fifteen years ago, it was about the durability and efficiency of hybrid vehicles. Now itís auto stop/start.
I know enough about automotive technologies and AS/S, and others have covered that side of it here. What interests me is the emotions that drive the resistance to these innovations. Why the dislike for AS/S ?
The dislike is that many of the posters here have dealt with unreliable cars their whole lives. Many American cars have had marginal reliability for decades, and European cars have become garbage for reliability in recent years. Even Honda started cost reducing around 2008 and their reliability went downhill.

Basically only Toyota - and not all models and years - has made consistently reliable cars for decades. Except for those Tanaka airbags and unintended acceleration.

So it feels like starting and stopping an engine is just one more reason to pay a mechanic to fix your ride.
#52
Old 05-21-2018, 04:25 AM
Guest
Join Date: Dec 2017
Location: Phoenix, AZ
Posts: 136
I guess I’ve been lucky, my cars have been pretty reliable. The German and American ones less than the Japanese ones, but all of them more reliable than the cars that built in the ‘60s and ‘70s. But if I’d had to deal with more breakdowns, maybe I’d long for less complex cars, that I could fix myself.
#53
Old 05-21-2018, 03:19 PM
Guest
Join Date: Jan 2017
Location: Chicago, IL
Posts: 1,383
One of mine is a 17 year old Chevy daily driver and it runs like a champ. Very few issues. Low Tech.

Reliability is relative and based on how well you take care of your vehicle and how much electronic garbage comes with the car.

Starting and stopping an engine is when the most engine wear happens.

Last edited by anomalous1; 05-21-2018 at 03:21 PM.
#54
Old 05-21-2018, 08:31 PM
Guest
Join Date: Dec 2017
Location: Phoenix, AZ
Posts: 136
Quote:
Originally Posted by anomalous1 View Post
One of mine is a 17 year old Chevy daily driver and it runs like a champ. Very few issues. Low Tech.

Reliability is relative and based on how well you take care of your vehicle and how much electronic garbage comes with the car.

Starting and stopping an engine is when the most engine wear happens.
Starting and stopping a COLD engine is when the most engine wear happens.
#55
Old 05-21-2018, 08:36 PM
Member
Join Date: May 2001
Location: Scottsdale, more-or-less
Posts: 15,623
The reality is, most modern engines don’t “wear out.”
General wear (rings, valve guides, journals, etc.) is rarely the cause of engine failure in modern cars. Something major, like a blown head gasket or oil starvation due to poor maintenance is more likely to result in an engine failure than simple wear.
And, if you see a car with obvious signs of wear (like blue smoke), then the body of the car is likely to be a wreck, too.
#56
Old 05-22-2018, 12:45 AM
Guest
Join Date: Feb 2009
Posts: 13,844
My wife has a 2008 Camry hybrid. The only real expense we've had was a thousand dollars plus of front end work to fix the steering and suspension due to bad roads. (your tax dollars not at work). The drive train works fine. It was a little disconcerting the first few months we had it, that the shudder of the engine starting happened about 10 feet after you start pulling out of the garage. The engine tends to run most of the time but will stop if we are waiting at lights and the AC or heating is not in high demand.

My 2014 BMW 328i stops whenever I come to a stop. It will start as soon as I take my foot off the brake, or try to turn the steering wheel (there's a momentary resistance on the steering until the power assist kicks in). It too will kick in at a stop if AC or heat is needed; I assume the water pump is not running without the engine so in winter, the engine will restart within about 20 seconds. Typically, it stops at a red light of similar traffic stop. If I inch forward, it will not stop a second time (I guess the internal logic decides it's "stop and go" traffic). I have to hit a decent speed or go a decent distance (exactly what, don't know) before the auto-stop happens again. I don't know what the transmission is doing, but I assume it disengages for the crank start.

In both cases the engines start in what feels to be one revolution, turn over and run within a second. None of the frequent cranking I remember from my really old cars. I knew someone who had T-bird, probably around 1985, and it had a bad habit of stalling at red lights randomly and not starting - usually in humid conditions around freezing... without benefit of auto-stop-start. She'd had it towed 10 times in less than a year. A hot engine does not always guarantee a start.

I guess the relative fuel economy depends on whether you do a lot of downtown stop-and-go driving (and the outside temperature).
#57
Old 05-22-2018, 01:17 PM
Member
Join Date: Jun 1999
Posts: 27,130
Quote:
Originally Posted by Telemark View Post
It appears to increase fuel economy around 10% - obviously depending on your driving patterns. This was back in 2014, so things are probably continuing to improve.

https://edmunds.com/car-reviews/...save-fuel.html
This will be highly dependent on where you live and the kind of driving you do. If you live in a place where your commute is dominated by traffic jams and/or you do lots of driving in dense urban cores with lots of traffic lights, this is going to save you a lot. On the other hand, if you drive mostly open highways or move around a lot in the 'burbs where there are few traffic jams and lights, not so much.

Sincerely,

Captain Obvious
#58
Old 05-22-2018, 03:41 PM
ftg ftg is offline
Guest
Join Date: Feb 2001
Location: Not the PNW :-(
Posts: 16,908
My random train of thought goes thus:

I wonder what would be the issues with keeping the motor barely turning. E.g., firing a cylinder here and there. Make it a random one so that the vibrations don't cascade.

So when it's time to go the startup time is shorter and possibly more reliable.

How often would a cylinder have to fire to keep things reasonably going?

All this, of course, makes me think of those old cylinder farm pumps with a governor ball which fire, spin for a while, fire again, etc. Make a weird, whump ... whump ... whump sound. Ah, the good old days.
#59
Old 05-22-2018, 04:31 PM
Guest
Join Date: Jan 2013
Posts: 2,969
Quote:
Originally Posted by Sam Stone View Post
This will be highly dependent on where you live and the kind of driving you do. If you live in a place where your commute is dominated by traffic jams and/or you do lots of driving in dense urban cores with lots of traffic lights, this is going to save you a lot. On the other hand, if you drive mostly open highways or move around a lot in the 'burbs where there are few traffic jams and lights, not so much.

Sincerely,

Captain Obvious
It doesn't take a really dense urban area for these systems to show the kind of improvements quoted. In those cases (driving in Manhattan say) it would probably be even more. AFAIK tooling around most US actual suburbs (not 'exburbs') at work drive times requires plenty of stopping. Some prototypical 'real Murrican' exurban/rural driver (composing maybe 10% or less of actual drivers) go on such open roads all the time it wouldn't make any difference. Then again the already overblown IMO predictions of maintenance nightmares would not come to pass for them either, because the system would hardly ever be activated.

Sincerely,

Grand Admiral Obvious (for the last part)

It's also IME obvious factually (maybe not emotionally, obviously not) that complication and reliability of cars do not correlate all that closely if that's all your look at. Cars now in general are vastly more reliable (in the strict meaning, not stuff like 'I can work on it myself', that's not reliability) than 1970's cars (I remember first hand) and much more complicated. It's also highly doubtful IMO now between recent model cars. Toyota might have the best reliability record overall in say the last decade or two, but it's not particularly because their cars are simpler than say the big US brands. They have some kind of institutional edge on quality/reliability even at the same level of car complexity. It's not national characteristics of assembly line workers since Toyota replicates their formula at factories around the world. It might be national characteristics of engineers to some degree since they are mostly though not entirely in Japan. Anyway the US brands have just never been able to catch up model year for model year with Toyota or the US brand v Japanese brands average either. But new US brand cars now are more reliable than new Toyota's were years ago, and typically quite reliable compared to what older drivers like myself experienced decades ago.

The best source of car reliability data, CR's, also tends to show (typically more complicated than usual) European luxury brands middle of the pack in reliability, tending more towards the top of the pack relatively recently. So no clear evidence there either that gadget/complication is enough of a factor in car reliability to stand out from all the other factors.
#60
Old 05-22-2018, 04:41 PM
Guest
Join Date: Feb 2017
Posts: 2,453
Quote:
Originally Posted by ftg View Post
My random train of thought goes thus:

I wonder what would be the issues with keeping the motor barely turning. E.g., firing a cylinder here and there. Make it a random one so that the vibrations don't cascade.

So when it's time to go the startup time is shorter and possibly more reliable.

How often would a cylinder have to fire to keep things reasonably going?

All this, of course, makes me think of those old cylinder farm pumps with a governor ball which fire, spin for a while, fire again, etc. Make a weird, whump ... whump ... whump sound. Ah, the good old days.
You're fighting all the friction of the system. Your efficiency levels are lower. Gas engines have an optimally efficient power level. I've heard that this is "wide open throttle", but this does not appear to be the case in my Prius. It seems to have a sweet spot that is at about 20% or 30% output that it wants to be in. I think it's a thermodynamics thing - it takes time for the gas in the cylinders to fully combust and for the power stroke to fully extract the energy. Running the engine faster is less efficient, and the Prius engine is small, optimized for lower weight and the power levels needed for normal driving.

Anyways, this "barely turning over" thing is a feature in numerous GM vehicles. They do idle while only using some of the cylinders. Still nothing like the efficiency of a Prius.

Instead, my Prius will run in short bursts at a more efficient level and store the extra energy over that is needed at the moment in the battery. So in residential streets, stop and go traffic, or if I am just sitting in the car enjoying the A/C, the engine will start, run for 1-4 minutes, and then stop again. If you're moving you can barely feel a judder though it is more obvious when stationary.

It absolutely is neat stuff. Of course, it's basically obsolete - BEVs are superior in every single respect except for the cost of the battery. The Prius is just an intermediate product, like the B-36 bomber.

I bought my Prius recently, since the data says it's one of the least expensive cars to maintain and it's obviously very economical in fuel. Bought a 6 year old one, since that's supposed to be the sweet spot on the depreciation curve between vehicle age and condition and cost, for 36% of what the original owner paid, while the vehicle has at least 66% of it's mileage life remaining.

Last edited by SamuelA; 05-22-2018 at 04:43 PM.
#61
Old 05-22-2018, 05:40 PM
Guest
Join Date: Feb 2010
Posts: 1,306
Quote:
Originally Posted by Capn Carl View Post
This thread has a similar character to other threads on a variety of forums, regarding new technologies. Ten or fifteen years ago, it was about the durability and efficiency of hybrid vehicles. Now itís auto stop/start.
I know enough about automotive technologies and AS/S, and others have covered that side of it here. What interests me is the emotions that drive the resistance to these innovations. Why the dislike for AS/S ?
I don't understand the "this is new and unproven" bit of the equation. The Prius was introduced in 1997. 1997! 20 years isn't "proven" enough? How long do people need to accept "new" inventions?
#62
Old 05-22-2018, 05:43 PM
Guest
Join Date: Feb 2017
Posts: 2,453
Quote:
Originally Posted by Blakeyrat View Post
I don't understand the "this is new and unproven" bit of the equation. The Prius was introduced in 1997. 1997! 20 years isn't "proven" enough? How long do people need to accept "new" inventions?
I think a lot of people assume the Prius is an expensive car to keep on the road, that it's going to blow it's engine or need new batteries far sooner. To the point that many people assume these extra costs exceed any gas savings, and people just drive Prii in order to feel superior. Everyone seems to assume the battery still costs 5k to replace (ok, it can if you let yourself get screwed at the dealer), that the engine is just one start/stop cycle from throwing a rod, and so on.

Last edited by SamuelA; 05-22-2018 at 05:44 PM.
#63
Old 05-22-2018, 05:45 PM
Guest
Join Date: Feb 2010
Posts: 1,306
Quote:
Originally Posted by SamuelA View Post
Of course, it's basically obsolete - BEVs are superior in every single respect except for the cost of the battery.
Well, 2017 hybrid Fusion has a range of 660 miles, while the best Tesla range is somewhere around half that. (315 IIRC.) So that's still a pretty big performance gap in that one area.

I have to admit, though, for the driving I do personally, 315 miles would be plenty.
#64
Old 05-22-2018, 05:54 PM
Guest
Join Date: Feb 2017
Posts: 2,453
Quote:
Originally Posted by Blakeyrat View Post
Well, 2017 hybrid Fusion has a range of 660 miles, while the best Tesla range is somewhere around half that. (315 IIRC.) So that's still a pretty big performance gap in that one area.

I have to admit, though, for the driving I do personally, 315 miles would be plenty.
Point taken. For larger states like Texas, maybe the residents need some kind of series hybrid so they can have that kind of range on tap. Right now, the Prius is a great car for Texas - except for that fact that most Texans prefer trucks.

Though...checking.

Houston to Dallas is 241 miles. San Antonio to Dallas is 292 miles. Still within Model 3 LR range, easy.

Last edited by SamuelA; 05-22-2018 at 05:58 PM.
#65
Old 05-22-2018, 08:37 PM
Member
Join Date: Aug 2010
Location: Under Oveur & over Unger
Posts: 11,360
Quote:
Originally Posted by ftg View Post
My random train of thought goes thus:

I wonder what would be the issues with keeping the motor barely turning. E.g., firing a cylinder here and there. Make it a random one so that the vibrations don't cascade.

So when it's time to go the startup time is shorter and possibly more reliable.

How often would a cylinder have to fire to keep things reasonably going?
often enough to basically run at standard idle speed.

what you propose (if it was even workable) would be a shuddering mess.

Quote:
All this, of course, makes me think of those old cylinder farm pumps with a governor ball which fire, spin for a while, fire again, etc. Make a weird, whump ... whump ... whump sound. Ah, the good old days.
that's a 'hit and miss" governor. those stationary engines run at very low RPM and have a massive flywheel to smooth out power fluctuations.

Last edited by jz78817; 05-22-2018 at 08:38 PM.
#66
Old 05-22-2018, 09:49 PM
Member
Join Date: Jun 1999
Posts: 27,130
Quote:
Originally Posted by SamuelA View Post
Point taken. For larger states like Texas, maybe the residents need some kind of series hybrid so they can have that kind of range on tap. Right now, the Prius is a great car for Texas - except for that fact that most Texans prefer trucks.

Though...checking.

Houston to Dallas is 241 miles. San Antonio to Dallas is 292 miles. Still within Model 3 LR range, easy.
No way. Just because a car is listed as 315 miles in range doesn't mean you can drive 292. With an electric car, you need to leave a serious margin for emergencies. You get to the charging station, and it's out of order. You get in a traffic jam. It's hot, so you need to run the AC and battery cooler. That sort of thing. I also wouldn't count on the battery being fully charged and in spec.

If I had an electric car with a 300 mile range, I'd be having range anxiety as soon as I hit 200. Likewise, my car has an 80km range after the low fuel warning comes on. So technically, I could drive to work and back a couple of times with my low fuel light on - but I never do. And running out of gas on the side of the road just means a cab bill for 5 gallons of gas. If your electric car dies on the side of the road, you are trailering it home or to the nearest charging station.

I hear there are some towing companies now that have trucks that can so a quick fast charge to get you a few miles down the road, but I wouldn't count on that.
#67
Old 05-22-2018, 09:56 PM
Guest
Join Date: Feb 2017
Posts: 2,453
Quote:
Originally Posted by Sam Stone View Post
No way. Just because a car is listed as 315 miles in range doesn't mean you can drive 292. With an electric car, you need to leave a serious margin for emergencies. You get to the charging station, and it's out of order.
Fair enough. Though this risk should diminish quite a bit as more chargers pop up. You're right, though, 292 is too far, you would risk damaging the battery.
#68
Old 05-22-2018, 10:10 PM
Member
Join Date: Jun 1999
Posts: 27,130
You also have to consider the conditions. For example, batteries in electric cars need to be operated in a fairly narrow temperature range. So if you are in a cold climate, you have to run the battery warmer. And in a hot climate, a cooler.

Also, any accessories you use will cut into range. So if you are running the A/C or the heater, that will diminish your range. To a lesser extent, so will the seat heaters, the stereo, etc.

Battery damage shouldn't be an issue, as the vehicle's electronics shouldn't allow you to discharge the battery that far, and the advertised range ahould already factor that in.

But still... In the worst case scenario your electric car can have as little as half of the advertised range, and that doesn't account for traffic jams and detours and the like.

310 miles of range is seriously good, and it makes the car usable for a lot of people. But even Tesla had to install large numbers of fast charge stations along popular routes before people were willing to drive their electic cars a long way from home.
#69
Old 05-22-2018, 10:13 PM
Guest
Join Date: Feb 2017
Posts: 2,453
Quote:
Originally Posted by Sam Stone View Post
You also have to consider the conditions. For example, batteries in electric cars need to be operated in a fairly narrow temperature range. So if you are in a cold climate, you have to run the battery warmer. And in a hot climate, a cooler.

Also, any accessories you use will cut into range. So if you are running the A/C or the heater, that will diminish your range. To a lesser extent, so will the seat heaters, the stereo, etc.

Battery damage shouldn't be an issue, as the vehicle's electronics shouldn't allow you to discharge the battery that far, and the advertised range ahould already factor that in.
This isn't quite true. Teslas by default only charge to 80% capacity because being charged higher than that does damage the battery. As well as discharging below 20%. It costs maybe a cycle every time you do that - meaning the battery lifespan loses 300 miles or so. Under great conditions, the Tesla LR battery could do 250-450k miles, so this loss isn't much, but it is there.

(about 1000-1500 cycles on LCA, depending on depth of discharge, before the battery is considered unserviceable)

Last edited by SamuelA; 05-22-2018 at 10:14 PM.
#70
Old 05-23-2018, 07:09 PM
Guest
Join Date: May 2011
Location: Orlando, Florida
Posts: 2,402
We just purchased a 2018 Jeep Grand Cherokee that had this feature. Thought I would hate it, but it is really unobtrusive. You feel a slight shudder when the endings restarts, but after a few times you forget about it. I also think that it can be adjusted as to the time stopped until the engine shuts off or even turned off. If it saves had, I really don't see the problem.
#71
Old 05-24-2018, 12:53 PM
Member
Join Date: Jun 1999
Posts: 27,130
Quote:
Originally Posted by SamuelA View Post
This isn't quite true. Teslas by default only charge to 80% capacity because being charged higher than that does damage the battery. As well as discharging below 20%. It costs maybe a cycle every time you do that - meaning the battery lifespan loses 300 miles or so. Under great conditions, the Tesla LR battery could do 250-450k miles, so this loss isn't much, but it is there.

(about 1000-1500 cycles on LCA, depending on depth of discharge, before the battery is considered unserviceable)
I thought the car electronics would prevent you from discharging the battery to the point of damage.
#72
Old 05-24-2018, 01:25 PM
Member
Join Date: Aug 2010
Location: Under Oveur & over Unger
Posts: 11,360
Quote:
Originally Posted by Sam Stone View Post
I thought the car electronics would prevent you from discharging the battery to the point of damage.
any competently designed battery manager for lithium cells will do everything it can to prevent damage to the cells.
#73
Old 05-24-2018, 01:54 PM
Guest
Join Date: Feb 2017
Posts: 2,453
Quote:
Originally Posted by Sam Stone View Post
I thought the car electronics would prevent you from discharging the battery to the point of damage.
Damage is a relative term. You get 1000 cycles from 20 to 100 percent, vs 2000 to 3000 cycling between 30 to 70 percent. Roughly. The exact cell construction and temperatures will have an effect on this.

So it's "easier" on the batteries if you electronically limit your Tesla to 70 percent charge and don't drive it below 30 percent very often.

Prius takes this a step further and only cycles in a very narrow range that is least damaging to the battery.
#74
Old 05-24-2018, 09:16 PM
Guest
Join Date: Dec 2017
Location: Phoenix, AZ
Posts: 136
It looks like the resistance to auto stop/start comes down to these two beliefs:
Starting the engine, even when hot, increases wear, more than having it stopped for brief periods decreases wear.
Increased complication>>>decreased reliability.
#75
Old 05-24-2018, 10:09 PM
Guest
Join Date: Feb 2017
Posts: 2,453
Quote:
Originally Posted by Capn Carl View Post
It looks like the resistance to auto stop/start comes down to these two beliefs:
Starting the engine, even when hot, increases wear, more than having it stopped for brief periods decreases wear.
Increased complication>>>decreased reliability.
And a third reason. If you need greater complexity for more fuel efficiency, many people consider that a bad tradeoff.

I've heard it argued that you should drive a 1 ton pickup truck around to do errands like you'd do in a station wagon.

Why? Because the drivetrain components, in an empty truck, are barely being stressed compared to what they would experience in a loaded truck. Ergo, they'll last forever.

Never mind that the truck burned through 30 - 50 thousand dollars in gasoline over it's 225,000 mile long life.
#76
Old 05-25-2018, 01:14 AM
Guest
Join Date: May 2018
Posts: 3
I think that everyone has missed the real reason for wear in the bearings during an engine start. When the engine is in use the bearings are under a regime called hydrodynamic lubrication. This means that the shaft and the bearing are not actually in contact and a thin film of oil is maintained between the two surfaces. A picture speaks a thousand words:

Photo

The wear is orders of magnitude lower and significantly quieter. When the engine stops the film is not maintained and the two surfaces grind upon start up, causing most of the wear.

As a consumer you need not be worried. The engine is still designed for the same life so now low friction coatings are applied to the bearing surfaces to minimise initial wear. Good oil helps too. Service intervals in Britain have changed from 1year/20,000 miles to 1year/12,500 miles which I attribute to this kind of thing.

A simple question to ask yourself is: Have you ever heard of a properly maintained car engine being scrapped because of a worn bearing?
#77
Old 05-25-2018, 05:47 AM
Guest
Join Date: Feb 2017
Posts: 2,453
Quote:
Originally Posted by porkbroth View Post
A simple question to ask yourself is: Have you ever heard of a properly maintained car engine being scrapped because of a worn bearing?
No. I have heard of Prius engine failures. A few things that lead to failure :

a. Head gaskets can blow, some at 195,000 miles, others at 295,000. A probability curve.

b. A few unlucky folks have actually had internal coolant leaks get so bad that the engine gets destroyed by hydraulic hammering. A couple photos on the forums, where (it's almost always well over 200,000 miles) there's actually a piece of the engine block missing. What happens is that if enough coolant leaks, it will create an in-compressible slug of water that if a moving part of the engine hits, the shock wave gets transferred to the engine casing and it can break.

c. It uses a special EGR system that has several components. This doesn't cause engine failure, but it can get clogged to the point that the engine won't run smoothly. Part of the trick of the Prius is it has some way to heat it's own coolant using the exhaust gas. This lets it heat very quickly so it gets the coolant to operating temperature in a very brief period of runtime.

Anyways, the ironic - ok, maybe not ironic - thing is that the actual engine failing on a Prius is probably the second most common cause of drivetrain failure. The battery does usually wear out sooner than the engine, but is easier to replace. The EV components don't fail often at all.
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 11:41 AM.

Send questions for Cecil Adams to: [email protected]

Send comments about this website to:

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Copyright © 2018 STM Reader, LLC.

Copyright © 2017
Best Topics: 1112 meaning protestant monks stelvin lux international cashier's check refrigerator vents pellet vs bb chuck berry piss partial container shipping mama gena reviews p0761 ford focus pope berries ancestry boards man vs chimp fight herbert menninger curious george tim conway elephant story transcript 2000 ford ranger transmission rebuild kit shoes hurt achilles tendon warm spot on leg validity of marriages abroad 18 wheeler front view when do you use parking lights can you teach high school with a phd what does mamacita means in spanish einstein marilyn monroe quote craftsman garage door opener trolley