I thought it pretty well established that auto on/off is bad for the engine, as is intermittently turning off some cylinders as some do. Is that wrong?
It sounds like you're talking more about systems that supposedly disengage some cylinders while the car is cruising. Some engines with that kind of technology have been known to damage cylinders for multitude of reasons.
That's very different from the start/stop feature they're talking about. That's about fully stopping the engine when you come to a complete stop like at a red light and then automatically starting again when you get off the brake.
I don’t think it’s pretty well established, there are cars that will happily stop and start the engine multiple times per minute, e.g. Toyota hybrids with their “HSD” drivetrain. It just requires some engineering.
Hybrids generally command the ICE to run when under higher loads or cold conditions, but they do get a bit of a break under low load conditions when they’re warmed up.
But they also start and stop way more than a gasoline-only car with stop-start. Because they stop and start repeatedly while driving too. Series hybrids even more so.
>But they also start and stop way more than a gasoline-only car with stop-start.
they do it very differently. My Prius never does that coughing sound that the start-stop engines frequently do. The powerful electric motor in Prius spins the engine to at least 1000rpm before fuel is injected. That way it is much easy on the engine and much more fuel efficient too.
“While aggressive start cycles (>20 cycles per day) could lead to premature failure in the starter system of
light- to medium-duty commercial fleet vehicles, modern fuel injection and engine control systems have
eliminated any issues associated with drivers of typical light-duty vehicles turning the engine off while
stationary for short periods and restarting the vehicles for <10 start events per day.” from https://publications.anl.gov/anlpubs/2015/05/115925.pdf
This paper seems to say that generally they aren’t a problem. I’ve only seen unsubstantiated claims that they are one.
That's very different from the start/stop feature they're talking about. That's about fully stopping the engine when you come to a complete stop like at a red light and then automatically starting again when you get off the brake.
Hearing regular start-stop on intersection gives me sorry feeling for the engine.
But they also start and stop way more than a gasoline-only car with stop-start. Because they stop and start repeatedly while driving too. Series hybrids even more so.
they do it very differently. My Prius never does that coughing sound that the start-stop engines frequently do. The powerful electric motor in Prius spins the engine to at least 1000rpm before fuel is injected. That way it is much easy on the engine and much more fuel efficient too.
This paper seems to say that generally they aren’t a problem. I’ve only seen unsubstantiated claims that they are one.