I don't think that is correct, many vehicles now have the auto start/stop as a way of meeting emissions requirements.

If it's so intensive, why is auto-stop/start such a common feature on many vehicles? Especially since it seems to improve city-cycle mpg ratings...

The feature is found mostly on hybrids and electrics. It relies on the batteries to start the process.

This is demonstrably false. Even new Jeep Wranglers and Gladiators come with auto start/stop, and those are about as far removed from hybrids as it gets.

“Mostly” includes exceptions.

My point was that most vehicles include this feature, even those you’d least expect it on.

My 2022 CRV ICE has this by default. You can turn it off but on by default every time you start the car (US law or something.)

Again, mostly means majority and allows for exceptions.

This is false.

Can you find a link that shows that ICE / non hybrid and non ev make up the majority of cars with automatic start and stop?

There's many 100% ICE vehicles that shutdown at stops.

Mostly means the majority and by construction allows for exceptions.

The motor stops at TDC under compression and then fires the spark plugs to restart, reducing wear on the starter.

For others that -- like me -- have no clue what TDC is, I did a quick search[0]:

> Top dead center, sometimes referred to as TDC, is the point in which the piston in the number one cylinder position of your engine is at its highest point on the compression stroke.

[0] https://www.wikihow.com/Find-Your-Engine%27s-Top-Dead-Center...

Auto stop/start requires some (mostly minor) modifications to the engine, as well as updated software so that it is used only in “ideal” conditions. And the engine shutdown is done in a way that makes it quick and easy to restart.

I’m not sure, is it even possible to use these systems on diesel motors?

Of course - I've had a diesel Nissan Qashqai with a start stop system all the way back in 2013. Never had any issues with it.

This is an amusing place where most of the advancement was probably in the starter. The same thing that lets you have a small charger for your laptop has helped get a smaller starter that won't drain after a few starts. There is a lot of work that goes into starting an engine.

It takes less fuel than most people think.

This is almost certainly one of those things where the tech has moved on. It definitely used to use a fair bit of fuel to get started. Not so much anymore.

Probably also depends on where you are? I'd imagine colder climates need to keep the engine running.

Even way back when it used a lot of fuel to get started, it only took a few seconds of engine off the make up that fuel.

I've had cars need jumping from too many starts draining the battery, though. So, mayhap it was less the fuel and more the battery/starter?

Modern cars will disable stop/start if the battery is low. My car won't even use the start/stop feature if the HVAC is operating at a 100% of it's capacity.

> to turn off the engine at every stop, and starting a vehicle is fuel intensive in an ICE vehicle

This is backwards. The whole point of these systems is that it costs more in fuel at idle than it does to stop and restart.

Lots of "pure" ICE cars have this now with some smarts about operating temperature, battery etc.

Idling was worse on carbs, sure, but even with injectors your fundamental problem is you don't have enough airflow, and you counteract that by richening the mix so you don't stall.

Not actually true.

https://en.m.wikipedia.org/wiki/Start-stop_system

Great link and a good resource for folks curious on this. I had posited that it was likely changes in the starter getting more efficient that has caused this to become more common. However, the article makes it clear that it is largely changes in how things are powered in the car. The specific point about the belt being used to power AC and such is likely the largest factor on why this is slowly going out. (And why it is more common in hybrids, since they had to be designed to power all systems without the belt.)

Is a very interesting case study in what software folks would call "tech debt."