Quote:
Originally Posted by cRiPpLe_rOoStEr
It's also worth to note what Mazda achieved with the SkyActiv-D engine, which has a 14:1 compression ratio, extremely low for Diesel standards, but leads to a complete combustion at lower temperatures, and then a lesser amount of NOx is generated - doesn't even require neither EGR or DEF to meet current EPA requirements, and also doesn't require a DPF.
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Not true. The SkyActiv-D engine has HIGH flow EGR and a DPF. The only thing lacking is aftertreatment for NOx reduction.
Still a very cool engine with interesting technology.
-Under certain conditions, the variable lift exhaust valves open during the intake stroke to allow cylinders to draw hot exhaust in to increase temperatures during low power situations - necessary with such a low compression ratio. This is aided by an intake throttle.
-Lightened up parts allow for a 5200 RPM redline.
A good story and writeup here:
Mazda