I don't think that's true anymore with modern engines. It's my understanding that the on / off strain is no longer a limiting factor on engine wear and that the emissions and fuel saving benefits may be mild but are real from a net efficiency standpoint. While emissions savings are probably the greatest, I'm using this primarily to save anything I can with wartime gas prices.

Turning on and off increases wear in cars not designed for it. The cars that have the feature have beefy starters, it is a non-issue. And it does save a bit of gas and emissions at red lights, and stopped in traffic, and especially for assholes that leave the car on while their partner goes for a "quick" grocery run.

I was thinking about this while driving my hybrid (Hyundai Santa Fe) after watching Technology Connections (and/or Connextras) video about hybrid powertrains.

My car stops its engine when it's not needed. But then it starts back up so smoothly? How? There's no cranking. It just goes, already at matching revs.

But then I realized that an electric motor is a starter. Duh.

Really recommend the videos (and channels) for anyone who hasn't seen it yet.

The hybrid power train really is an amazingly simple thing.

Oh, regen braking? Just as I had thought, it's basically engine braking. Except when you're engine braking in an ice car, that energy is all wasted as heat and noise...in electric/hybrid, your motor turns into an Eaton Crank Radio, powered by the momentum of the wheels.

I used to drive ever-so-gently trying to minimize using the gas engine. But he made it so obvious that that's the wrong way to do it. All the energy that the car uses comes from gas, and it either gets used to push the car forward, or to recharge the batteries...and charging the batteries is a conversion step with its own implicit losses.