Auto start/stop, do you leave it on or disable it?

It's a good thing because if I put the truck in park, it means I'm not going anywhere. So shut off the engine and save gas. That's my point, it sounds like it's not working correctly. If I'm waiting for someone sitting in the truck in park, stay off. If I'm arriving at a parking spot, truck shuts off, I should then be able to power down fully to exit the truck by pressing the start/stop button. If I'm stuck in heavy traffic and put in park, stay off.

In park, the truck should never come back on unless the HVAC demands it.

 

understood but the hybrid motor does this until the oil pressure is at a predetermined point. Once this happens then the engine will engage ignition.

this manner of starting reduces the issues with bearing wear.

non hybrid systems engage ignition almost immediately.

 

How do you know this or are you making an assumption?

 

one way to look at this at a high level:

go to dashboard-light.com and peruse the different categories.

the FJ, land cruiser, 4runner, tundra, Tacoma, highlander, are overall quality leaders. 5 out of 6 of these nameplates did not have auto start stop for their entire generational life cycle, and that life cycle was absurdly long.

Highlander has had auto start stop since 2017. Tacoma still doesn’t have it yet and both have same engines.

highlander and Tacoma are very similar profiles : 20,000 vehicle sample size across all years, share v6 engine in latest generation, highlander has more average miles than Tacoma ( 153k vs 135k).

tacoma registers 4.3% engine issues reported and highlander registers 6.3%.

hard to know what engine makes up these issues and hard to know if auto start stop is disengaged 100% of the time or not. And highlander had only had it for 5 years.

The other nameplates haven’t had it. The other nameplates also have a contingent of their customer base that are known to tax their vehicles more and more often then highlander customers.

4 runner also has a history back to the 22r days in early 1990s so age is a factor here.

All 6 nameplates have huge gaps over the industry average in reliability. Highlander is the only one with auto start stop and has had it since only 2017. Even then most people disable the auto start stop system.

Outside of highlander, the other name plates above have astonishingly better reliability than other non Toyota nameplates which have had auto start stop for much longer periods.

comparing Prius , Corolla, Camry to their respective classes shows the same trend.

lesson I take away : auto start stop will likely have an impact on reliability long term. However it’s impact does not overshadow or overcome crappy designs and manufacturing.

it does actually appear that Toyota has something going on to their benefit with their auto start stop system compared to others. Not sure what that is besides the braking feature allowing a pseudo bypass.

ranking systems in long term reliability:
Toyota without auto start stop
Toyota with auto start stop

Non Toyota without auto start stop



Non Toyota with auto start stop.

 

https://auto.howstuffworks.com/fuel-efficiency/hybrid-technology/toyota-prius.htm

https://exclusivelyhybrid.com/how-does-a-prius-work/

This response is the best yet on how the auto start stop works in a Prius:

https://www.quora.com/How-does-a-Prius-starter-work

 

fair point. I was thinking in-terms of stop and go traffic jam situations. Non hybrid rentals are brutal and shutdown and start with every brake application to zero speed. Hybrids I’ve driven can run off battery if you are creeping along for some time depending on charge.

 

That doesn’t really make sense because the engine starts up right away, less than 1 second. My dad has a Prius and I’ve driven it a lot, the engine start time is as quick if not quicker than a non-hybrid. So that doesn’t given oil pressure enough time to increase.

 

https://m.youtube.com/watch?v=ZmHpSyTsfm0

 

Are you referring to the oil pump he put into the shaft of MG2? That’s should be the CVT gear oil pump.

When I accelerate from a stop, the MG2 power isn’t enough to satisfy my power request so the engine fires up right away before the car has started moving. It doesn’t seem like it has enough time to prime the engine oil pump like you’re saying.

 

nope.

mg1 rotates your engine. Then as conditions dictate the system then enables fuel and ignition. Then the engine is powering the whole drivetrain.
This is what the video shows and it also corroborates the other description I posted as well as my own understanding.

engine rotation does not equate to engine starting.

thus the engine oil pump is rotated by mg1. This is a friendly situation for oil wetted parts of the engine. Much more than the non hybrid start stops.

 

… you can literally hear the engine fire up and you feel the vibration of the engine firing too. It takes less than a second for the engine to fire and produce torque to propel the vehicle. I understand what you’re trying to say but it doesn’t match what the vehicle is doing. Also, you don’t actually know the engine starting control of the car and are just copy-pasting the evidence that supporters your argument.

 

If mg1 is rotating the engine then you will feel vibration.

I can’t help you any further then what I have done. You need to engage this subject on your own.

Your quip is a hot take from someone getting spoon fed information.

 

I’m not sure if this was brought up. If you drive the 2022 Tundra normally, the auto stop will not engage unless you deliberately force push the brake more at stop. This is really nice. I have 500 miles on my truck, and the auto stop has not engaged once. It says, please push the brake more to engage auto stop. I do not, so I don’t have to worry about it.

 

Here is an additional link describing the system. The first paragraphs show exactly what mg1 does.

http://prius.ecrostech.com/original/Understanding/WhatsGoingOnAsIDrive.htm

To bring this back to the very original argument, this is why hybrid systems are easier on oil wetted parts than a non hybrid start stop.

from an epistemological standpoint your argument about me pasting links ( to help you understand) is preposterous and embarrassing.

I can tell you that the earth is round and post links to a derivation and experimental evidence as well as pictures from orbiting devices.

But since I am posting someone else’s work apparently it isn’t believable.

You do your own research. I’ve done mine and more.

 

The last batch of links are all anecdotal at best. I’m supposed to believe a guy in Quora is an expert on Toyota’s control strategy for starting the ICE in series-parallel hybrid? Your second link is much more correct on how the system operates. But there’s no indication in that Prius engine starts are any easier on engine internals than Tundra and no indication that oil pressure is increased before firing. Oil pressure will automatically rise because of cranking in both situations though. From my own observation, Prius engine start and Tundra engine start are essentially the same in terms of engine response. So finally, my main point is if a 300k mile Prius engine has good bearing surfaces, likely a 200k mile Tundra engine will be similar.

 

Not to be a sexist or anything here, it is 2022 and all but facts are facts, the one thing you didnt touch on out of all those toyotas listed was the highlander is the only one of those that is likely driven predominantly by women/mothers. Women tend not to pay as much attention to the maintenance of their car and likely do more cold starts for short trips around town for shopping or taking kids places. I would also bet my next paycheck that women are far less likely to turn off the auto start/stop than men. I think this may actually be an important factor in this particular example you gave.

 

I think saying "significant" depends on how you define it.

I have a Titan that is every bit as much of a gas guzzler as the 5.7 Tundra. On a long road trip I can burn through an entire tank of gas (well, not completely empty, just around E or fuel light just come on, about 22-23 gallons) in under 5 hours.
We take lots of road trips in the Titan, and more than once we've been stuck in some kind of traffic jam.

A notable one was going through the Siskiyou pass during winter snowstorm, semi up ahead jackknifed. We had 3/4 tank of fuel, it was below freezing outside and we were stuck slightly more than 3 hours. We idled the entire time. I swear the truck barely used any fuel, the gas gauge barely moved at all. Knowing how quickly that truck can burn through gas every hour when driving, seeing it barely use any gas in 3 hours was astounding, because we were a little anxious it would use too much to idle.

I'm pretty sure the new Tundra would've idled the majority of the time in that situation, too cold for frequent shutting off.

 

Interesting?
I am willing to bet that most Women I know would not actually understand or sense what is even happening especially after an initial period where they get used to it.

Also in a Prius the vehicle is already moving many times making the added power from the Engine a lot less abrupt an addition than in a drivetrain completely shut down and powering up to move at all.

Apples to Applesauce sort of comparisons?

 

apples to applesauce, i like that. Stolen.

 

If disabled when driving, does the start/stop feature stay off, or does this need to be done each time?

 

Every…fucking…time…

 

And this is why it sucks so completely to me!

 

Link: https://www.tundras.com/threads/a-d...-data-logger-instant-mpg.101602/#post-2602703
He measure 1.6 gallon/hr (~121 mL/min, ~4 oz/min) on his Tundra. Seems like a lot to me but could have been with AC on or heater on which changes idle speed. Also park idle speed is different from drive idle speed. I imagine drive will use more fuel at idle even at a lower idle speed because of the drag from the torque converter.

 

All the sources I posted agree with each other. Every. Single. One. Disregard whatever sources you wish it doesn't change the facts of the matter.

Upthread there are links to university studies on tribology of bearings used in auto start stop. You don't need to read the whole article, the abstract clearly indicates that auto start stop systems are likely to damage bearings.

But you are going with your own experiences and a random youtube video.

Please keep lecturing me and all of us on "anecdotes" and proper sources. It looks like simple terminology like "anecdote" is new material for you as well.

You are conflating start with rotation. The MG1 spins the ICE. MG1 is the starter. This spins the mechanical oil pump. The ICE starts with only 2 cylinders after MG1 spins it. This whole operation is much easier on main bearings and rod bearings than non hybrid systems.

 

That seems like a lot!

I'd think the 5.7 probably burns through 4g/hr at 65 mph (fuzzy maffs) so 1.6 seems really high for not moving. As I don't own a 5.7 Toyota I can't say much about his results.

If my truck burned 1.6/hr I would've consumed almost 5 gallons in my example, that be just short of a 1/4 tank on my fuel gauge. Yikes!

My case was with HVAC on heat and AC, interior lights on, laptop and DVD player powered by truck and running the nav/stereo at moderate volume

 

How is starting by MG fundamentally different than starting by a starter? The only difference is the starting speed, a 12V starter will spin the engine at 400~500 rpm before starting and oil pressure will be produced. Anyway, this discussion is devolving so l will stop here. There’s no data or primary source evidence provided outlining the control strategies of either conventional or hybrid engine cranking so there’s no point to continue.

 

You are looking at the wrong "fundamentals".

The importance of MG1 isn't that it acts as an ICE starter. In fact this isn't important at all. The importance comes from the MG1 spinning the ICE at 1000 rpms prior to starting on two cylinders. This is cogent--1) starting loads on bearings are much lower and the lubrication requirements are also lesser than a full power start. 2) Even if the cycle for MG1 to spin the ICE is approximately 1 second that is an appreciable amount of time for flow of oil.

In reality the start up system of the prius is complex. What you are experiencing when cold is the ICE starting up. This is no different than a traditional 4 cylinder 4 stroke system. After this there are several warm up regimes that the prius system goes through. It is in these, as well as the full warm up regime with battery power, that a hybrid system can reduce the wear rate on oil wetted parts. The hybrid system can move forward on battery power through MG2 up to a certain, appreciable vehicle speed, and accelerator position.

When evaluated as a total system, the hybrid system (at least as Toyota has executed it in Prius) can reduce wear rate on bearings, pistons, rings even with crappy maintenance.

Non-hybrid systems can't do this.

The start stop system operates in a substantially different way. The engine has to reach increasing power levels much quicker to move the vehicle. (Again, where hybrids can move under battery power). This means the loads on bearings and pistons are increased. These loads can be somewhat reduced via cam timing and cylinder deactivation, but compared to a hybrid system it is much higher. And for the 3rd or 4th time tribology matters on bearings. And for the 3rd or 4th time the lubrication regime is boundary, mixed, hydrodynamic in order of ability to withstand increasing loads. You must understand both to understand bearing longevity.

Here are informative threads discussing the complex nature of the prius system.

Gen3 warming up stages | PriusChat

The Five Stages of Prius Hybrid Operation | PriusChat

Vehicle warm-up behavior - ScanGauge observations | PriusChat

The information "you require" isn't available over an open source as it is likely a trade secret situation or possibly a patent in the making. OEMs aren't friendly with sharing information that pertains to systems they have that are competitive advantages. This is manifestly obvious. You simply have to live with information from other sources to build a signal to noise ratio that is meaningful for purposes of learning. This requires action on your part, not others. Making requirements of perfect sources to discuss and learn and debate is an old but cheap tactic. I'm not impressed with it.

 

Loved the use of "hydrodynamic".

 

I got my buddy to help me take some techstream data of my dad’s ‘20 Prius and my ‘22 Tundra. We could see both MG speeds, engine speed, and engine torque in the Prius. In the Tundra I missed engine torque but got spark timing, battery voltage, and engine speed. So we can kind of gauge when the engine is firing in both cases.
Test case: take off from a stop with moderate acceleration
Result: Both Tundra and Prius engine start in about 0.5 sec.

Prius MG1 is spinning backwards at start (negative rotation) and at 1 sec mark MG1 starts to crank the engine. At 1.5 sec mark engine torque is greater than zero so engine should be firing. Engine speed is around 1000 rpm at 1.5 sec mark. So engine is started in 0.5 sec.


Tundra starts cranking at 0.5 sec mark, battery voltage drops to around 10V during cranking. At 1 sec mark spark is increasing and engine speed starts to rise again so this means engine is firing. Engine speed is 800 rpm at 1 sec mark. Again engine is started in 0.5 sec.


I can’t imagine why Toyota wouldn’t apply the same firing control to smooth out engine starts for Tundra. But without deeper analysis of engine cranking we won’t know. Anyway, looks like engine starting is similar for Prius and Tundra.

Based on one data point, if we assume that after 300k miles a Prius engines cam, crank, and rod bearings are in decent condition, it isn’t a stretch to say that Tundra’s engine bearings might be in similar condition after 300k with normal maintenance.