Lambda 1 Regs

[arcamalpha]

I thought it would be interesting to explore this topic and didn't find anything on it yet. I have no details myself (sorry!) but hoped some of you might know the regs and/or the science and what it might mean for future Porsche engines beyond the 992.2 GTS.

[GT3ZZZ]

Don't know much about it either but the bald facts are clear with 992.2.

Capacity bumped by 20% from 3.0L to 3.6L and both cars released so far only make a handful more ICE horses, so the engine changes appear to be emissions focused and need a lot more capacity to do the same as 992.1.

[arcamalpha]

GT3ZZZ said:

Don't know much about it either but the bald facts are clear with 992.2.

Capacity bumped by 20% from 3.0L to 3.6L and both cars released so far only make a handful more ICE horses, so the engine changes appear to be emissions focused and need a lot more capacity to do the same as 992.1.

I wonder if it'll be a big driver for engines to come. Emissions haven't driven the 992.2 GTS spec choices; its CO2 figures are the same as 992.1. It's either the need to not be pure ICE for ~2035 regs or it's because of Lambda = 1.

If it's about lambda, I wonder what design features and limitations it drives?

The main reason to run rich is for piston crown and valve cooling (I think). I think the heat is mostly generated by engine speed and from combustion pressure. Larger capacity engines require less boost to generate a given torque so can run cooler in the combustion chamber.

That's presumably part of the reason for going from 3.0 to 3.6. I wonder also if the cylinder geometry of the 3.6 is somehow more efficient meaning it can get away with being relatively leaner at higher revs where engines tend to run richer. I wonder if we'll also see more fancy materials introduced to withstand the heat in higher performance engines. The Turbo model will be interesting.

[Guyr]

CO2 is only one part of emissions regulations and tests and is largely reflective of fuel consumption, which is why it hasn't changed. The Lambda one running means it burns cleaner and emits less of the other pollutants. Presumably Porsche must have decided to do so for good reason.