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Originally Posted by arghx7
They are describing a very late port injection timing, which is normally terrible for HC emissions... I don't see the cat lightoff strategy on the FA20 surviving the upcoming emission standards. There's too much HC and particulates to overcome. That's one of the reasons why Audi uses DI only.
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Do you see Subaru choosing a different playbook of software tricks... or a diesel-like aftertreatment setup?
I'd actually be OK with a particulate filter and NOx trap, but they cost money. Restructuring the combustion chamber and timings could also just target different temperature/pressure ranges. That would prevent the HC from forming in the first place.
Quote:
Originally Posted by arghx7
If the cat doesn't light off in time, or the engine-out emissions are too high, the engine doesn't get certified and doesn't go to production. So I'm not sure what the original source of that claim is from.
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Just alot of complaining from engineers higher up the R&D food chain.
Some day in-cylinder pressure sensors will be cheap enough to obsolete oxygen sensor feedback.
Quote:
Originally Posted by arghx7
There are a bunch of tricks in the bag. Some involve lean burn and expensive o2 sensors that light off very quickly. Some involve smog pumps (secondary air injection) or HC trap catalysts. Some involve tumble control valves, or expensive DI systems, or valve timing tricks.
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As simple as tumble/swirl control is... I'm expecting that the improvements to ANSYS and other fancier FEA programs will yield major gains in this regard. Piston shaping and dual valves are "easy" technology to develop if you can guarantee the resulting performance doesn't yield gains that bite you somewhere else in the operating range.
Quote:
Originally Posted by arghx7
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Sweet! Injection timing tables exist.
That 370 deg is quite interesting. Not sure if they're using fuel to cool certain parts or if they're forcing the maximum value possible.
During my time perusing blue oval code, they did the latter a few times. Generally when they wanted something fully open or closed, you'd see weird values.