HowlerMonkey Posted April 5, 2009 Share Posted April 5, 2009 Stratified charge is multiple spark. Some direct injection schemes use multiple spray events.......I know.......I don't need to google it because I am a direct injection certified Lexus Technician. Direct injection atomizes the fuel to an unbelievable degree using up to 2000psi.......much better than injecting it against the back of a closed intake valve at 43psi pressure. Turbulence has been used mainly to hold relatively large fuel droplets as delivered by 43psi injectors to hold the fuel in suspension. With high pressure direct injection, this isn't an issue and that is why they can run super lean air/fuel ratios and high compression ratios up to 12 to 1 with regular unleaded gasoline. Now this is a nissan L6 forum and I doubt anybody is even thinking about direct injection since most here aren't pursuing anything past bank fired injection except in relatively recent Haltech, Electromotive setups..........so the grooves might be worth pursuing but I would combine it with a true sequential setup if I spent the time to machine the head. Quote Link to comment Share on other sites More sharing options...
rsicard Posted April 5, 2009 Share Posted April 5, 2009 Stratified charge is multiple spark. Some direct injection schemes use multiple spray events.......I know.......I don't need to google it because I am a direct injection certified Lexus Technician. Direct injection atomizes the fuel to an unbelievable degree using up to 2000psi.......much better than injecting it against the back of a closed intake valve at 43psi pressure. Turbulence has been used mainly to hold relatively large fuel droplets as delivered by 43psi injectors to hold the fuel in suspension. With high pressure direct injection, this isn't an issue and that is why they can run super lean air/fuel ratios and high compression ratios up to 12 to 1 with regular unleaded gasoline. Now this is a nissan L6 forum and I doubt anybody is even thinking about direct injection since most here aren't pursuing anything past bank fired injection except in relatively recent Haltech, Electromotive setups..........so the grooves might be worth pursuing but I would combine it with a true sequential setup if I spent the time to machine the head. HowlerMonkey: Is this to say that stratisfied charge is direct injection or vice-versa? Direct Injection Gasoline is a very interesting subject. The high pressure fuel is the same method used in Diesel Engines. What mechanism do the direct injectors use? Is is magnetic or piezo electric? Bosch pioneered the piezo electric injectors. With multiple spray events piezo injectors are likely being used as they have a faster response time. For all those following posts on these subjects, I was at the Super Chevy show/drag meet and met a gentlemen, who was Drag Racing, that said his sweet spot for ignition timing lead on a Small Block Chevrolet engine is 41 degrees! He describe the amount of dome on the pistons and the compression ratio. I was absolutely flabergasted. He did not have a CLUE about combustion flame travel speed. The dome impedes faster travel of the flame front and therefore MORE lead timing is needed. The trick is to use a FLAT top piston with a SMALL chamber head, for compression, that has good swirl and quench/squish with LESS lead ignition timing. Quote Link to comment Share on other sites More sharing options...
Careless Posted April 6, 2009 Share Posted April 6, 2009 sorry to say, but I'm wondering when someone is going to figure out a direct injection port on the Z instead of a grooved cylinder head. I mean... crazier things have been done before that come to mind. Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted April 6, 2009 Share Posted April 6, 2009 Shouldn't have mentioned it since it is tons more involved but it really is the future..........just too soon to be affordable or doable at this time. Quote Link to comment Share on other sites More sharing options...
kiwi303 Posted April 6, 2009 Share Posted April 6, 2009 Theres already some spark plug/injector combo out there I think ,I've seen mention of it, so that port injection engines can be converted to direct injection. It's just experimental as yet, but if the technology becomes affordable, I could see older engines being converted. But it's far more likely the idea will die out due to lack of interest. the big engine makers just make their new engines direct injection from scratch, and the numbers interested in converting from port to direct on an older engine probably aren't enough to justify producing it. Quote Link to comment Share on other sites More sharing options...
rsicard Posted April 7, 2009 Share Posted April 7, 2009 HowlerMonkey: It's very INTERESTING to look at new technologies to see if some of it can be extracted and used in the near future. As for direct injection, the reaction time of the injectors and speed of the driving electronics are the basis of this type of injection. Software and data acquisition and tweaking the software algorithms are the keys to increase efficiency. Quote Link to comment Share on other sites More sharing options...
Careless Posted April 7, 2009 Share Posted April 7, 2009 well perhaps some of you guys can share some good first-hand info on direct injection systems through another thread... I'd be interested in reading some of it. Quote Link to comment Share on other sites More sharing options...
Oddmanout84 Posted March 17, 2011 Share Posted March 17, 2011 I'm still curious as to if anyone has tried this on an L6, flat top piston or otherwise. Quote Link to comment Share on other sites More sharing options...
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