recklessOP Posted October 11, 2004 Report Share Posted October 11, 2004 direct injection is already VERY popular overseas... smile.gif i'm not familiar with mazda's system, but i do know a fair bit about mitsubishi's DI engines. the intake runner and piston/chamber design are quite a bit different from a conventional MPI engine. toyota's DI engines are setup the same way iirc. a small amount of fuel is injected during the intake stroke to help cool the incoming air and improve volumetric efficiency. they use an upright intake port and a specially shaped piston to generate swirl during the compression stroke. the rest of the fuel is injected as the piston approaches TDC during the compression stroke. the piston is shaped to concentrate fuel around the spark plug prior to ignition, so the engine will continue to fire at very lean air/fuel ratios. under light load, you'll see air/fuel ratios approaching 1:40. injecting the fuel just prior to ignition also cools the mixture and helps stave off detonation. static compression ratios of 12.5:1 are manageable... problem is, this system won't work in the US. the super lean air/fuel ratios generate excessive NOx emissions, and a special converter is needed. high sulphur fuel will damage the converters... renault has developed a DI engine that would work here. instead of using super lean air/fuel ratios to improve efficiency, they increase EGR at part throttle/light load. even at 25% EGR, the chamber design on a DI engine will still allow the engine to fire. horsepower is boosted with higher static compression ratios... good luck finding upgraded fuel system parts. the systems i've seen run at 1450 psi... tongue.gif audi has been using DI engines since 2001... smile.gif http://www.mulsannescorner.com/Audi-GC2.jpg Quote Link to comment Share on other sites More sharing options...
Maro Posted October 11, 2004 Report Share Posted October 11, 2004 Looks A LOT like my Legacy GT.... nice looking car.... Quote Link to comment Share on other sites More sharing options...
Mowgli1647545497 Posted October 11, 2004 Report Share Posted October 11, 2004 Originally posted by Maro: Looks NOT like my Legacy GT.... nice looking car.... fixed Quote Link to comment Share on other sites More sharing options...
Mallard Posted October 11, 2004 Author Report Share Posted October 11, 2004 Neo, what you say seems to be in line with everything I've read. Like RecklessOP said, the pistons are oddly shaped in order to concentrate the a/f mix near the the spark plug. Mitsubishi has been using DI for a while. In the 1980's GM pioneered DI technology, but the program got shelved. Mitsubishi continued with what GM started and refined it to where it is today. The Mazda engine has been in production in Japan, so it's not exclusive to this model. From everything I've heard, this powertrain is built a lot better to handle boost with great power delivery and drivability. (Unlike my car which basically got a bolt-on turbo kit) I have personally not driven it, but a friend-of-a-friend has, and he says the car is pretty solid. I will be watching dealer lots closely. Quote Link to comment Share on other sites More sharing options...
Orion Posted October 12, 2004 Report Share Posted October 12, 2004 phil, the second you see one of these, youd better be on the phone to me. i wonder how mod-freindly a car like this would be? Quote Link to comment Share on other sites More sharing options...
Mallard Posted October 12, 2004 Author Report Share Posted October 12, 2004 I've heard they'll be out around Christmas or the beginning of the year, but no official word yet. Should be semi-mod friendly since it was actually built for boost. Here's a link with a lot of information. The torque curve looks NICE! http://www.triplezoom.com/news/publish/article_242.shtml Quote Link to comment Share on other sites More sharing options...
Maro Posted October 12, 2004 Report Share Posted October 12, 2004 Originally posted by Mowgli: fixed graemlins/finger.gif Quote Link to comment Share on other sites More sharing options...
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