Quote:
Originally Posted by Allch Chcar
Your second paragraph is a little confusing. 40:1 is the ideal burn rate but that doesn't mean the exhaust Lambda reading is going to be different?
Ultra lean would fail US emissions due to NOx. So he is either talking about the overseas versions or "stratified charge" like cerealkiller mentioned  .
Piston dome isn't new. Honda is doing that with it's high compression engines for a more efficient burn. It is better than dish from what I've read so that's good to know.
Some of it seems logical but not all of it concurs with what I know about DI as a whole... |
He says that direct injection engines by themselves produce dangerously high levels of NoX because by nature they operate at ultra-lean conditions. But in conjunction with port injection, a specifically designed EGR, and a specifically designed lean Catalyc converter, the NoX levels are tamed for emissions.
Quote:
Originally Posted by Nurburgring
Did he mention anything related to reliability of the system? shoud be pretty mature by now, but you never know. Itīll be a bitch to tune for bigger cams thatīs for sure!
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He says that the system seems reliable as the next, his biggest concerns are for tuners.
Do not delete the EGR, and do not go straight pipe. He has seen pretty bad engine failure for those D-4S equipped engines when people start treating them like normal fuel injected engines during modding, and he sees really bad deposits of carbon and crud with cars that that run on the track almost exclusively because they run at high load/WOT which is DI only.
Im learning as a I along, and read and do research and talk with him and some other people. I have some experience with DI, but nothing crazy.
Iv been reading up on some Mazdaspeed3 guys with DI, and they are having bad engine failure at their target AFRs when tuning and finding the right rich setting for a modded engine is tricky.
I dunno it just seems so weird to me, none of the applied technology is complicated, and the theory seems straight forward there is nothing thats particularly new. But the conditions and environment in the combustion chamber with GDI and D-4S are worlds apart from what Im familiar with.
on a interesting note someone was also talking about adding Direct Injection hydrogen to a gasoline engine, which brings the AFR to like 180 or some shit and internal compression to 30:1. Im like
