Comment by toxik
16 hours ago
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?
16 hours ago
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?
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.
I don’t think Toyota engine does traction from low rpm. Electric motor does it, and moments later already well spinning engine gets the load.
Hearing regular start-stop on intersection gives me sorry feeling for the engine.
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.
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“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.
This paper reads like a high school science fair project with zero treatment for the concern originally presented (oil system pressure transients).
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.