school me on DI engines please

[michaelluscher]

Originally Posted By: johnachak
I'll bet they read the manual for their $100 Bluray player though


I am employed in the tech sector and take a personal interest in such things, I also read the talesfromtechsupport subreddit

............you've put too much faith in people with that statement

 

[boundarylayer]

Originally Posted By: johnachak
GM cut the oil change interval to 7,500 miles which is not so "Wasteful" in my opinion. Many automakers use a 7,500 mile OCI..


You're lucky to get 4,000 mile OCI's on other GM vehicles with that same DI engine. Typical is 3,000.

 

[BearZDefect]

Did I read that SWRI pdf on particle emissions correctly? The chart at the end suggests that GDI engines emit around 30x as much as PFI, at least under some conditions.

 

[jrustles]

Originally Posted By: BearZDefect
Did I read that SWRI pdf on particle emissions correctly? The chart at the end suggests that GDI engines emit around 30x as much as PFI, at least under some conditions.


That's true. High load, high RPM. DI doesn't like high RPM-
the fuel doesn't have enough time to vapourize IMO.

I personally like DI. It means more static compression = more torque on the same cheap stuff (=efficiency, enabling downsizing). This is a honeypot for any emission and economy-compliant automaker.

Sure, most of them latched onto the tech prematurely IMO, to make the grade, but this shouldn't reflect badly on the technology as a whole.

 

[artificialist]

I think GDI leads to lower amounts of certain pollutants, and some auto makers might have to use it to meet stricter smog laws.

 

[MCompact]

My one owner Mazdaspeed 3 now has 139,000 miles on it and it is still running great. I've added a Mazdaspeed CAI as well as a Hypertech tune. It currently makes @300 bhp at the crank as well as @320 lb-ft of torque. At a steady cruise of 70 mph it returns 31 mpg.
So you could say that I'm pretty happy with DI so far.

 

[Quattro Pete]

Originally Posted By: artificialist
I think GDI leads to lower amounts of certain pollutants, and some auto makers might have to use it to meet stricter smog laws.

While they may emit less CO2 because they're more fuel efficient, they emit a lot more dirt particles...

http://www.transportenvironment.org/press/new-petrol-engines-cause-more-air-pollution-dirty-diesels

http://www.transportenvironment.org/sites/te/files/publications/GDI Briefing_final_T&E.pdf

 

[TiredTrucker]

Originally Posted By: spasm3


The unwashed intake valve may be a problem though, unless the figure out another way to feed the crankcase vapors into the motor.


I already did. It is called a PCV catch can. Same principle as the CCV filtration on commercial diesels from Cummins, Detroit, etc. In 11,000 miles, my catch can collected enough oil, condensation, etc to fill a 16 oz drinking water bottle.

 

[stickybuns]

Originally Posted By: BearZDefect
Did I read that SWRI pdf on particle emissions correctly? The chart at the end suggests that GDI engines emit around 30x as much as PFI, at least under some conditions.
I get 14 times, as in 1.4E12 / 1E11, from reading the chart (the difference between 1E11 and 1.5E12 is where the 1.4E12 comes from).

 

[stickybuns]

Originally Posted By: Rickey

Some manufacturers utilize this technology better than others.

Can someone point out a GM or Ford DI product that has a problem caused by the DI?



ford ecoboost problems: http://www.youtube.com/watch?v=nK2eXdaydqI

http://www.camaro5.com/forums/showthread.php?t=290860

http://www.edmunds.com/autoobserver-archive/2011/06/direct-injection-fouls-some-early-adopters.html

 

[itguy08]

Love both of mine. One just crossed 76k and no issues. Never had the intake off it and probably won't.

Sure the early ones had issues. But with a good design, such as the Ford units the chances of issues are greatly reduced. Ford has sold well over 1 million Ecoboosts since 2009 and issues are rare, even as these engines age.

 

[artificialist]

Originally Posted By: Quattro Pete
Originally Posted By: artificialist
I think GDI leads to lower amounts of certain pollutants, and some auto makers might have to use it to meet stricter smog laws.

While they may emit less CO2 because they're more fuel efficient, they emit a lot more dirt particles...

http://www.transportenvironment.org/press/new-petrol-engines-cause-more-air-pollution-dirty-diesels

http://www.transportenvironment.org/sites/te/files/publications/GDI Briefing_final_T&E.pdf


True, particulates were worse, but nobody mentioned if GDI changes NOx or CO emissions.

 

[boundarylayer]

Originally Posted By: artificialist

True, particulates were worse, but nobody mentioned if GDI changes NOx or CO emissions.


Passes EPA emissions tests, thats all we care about for NOx or CO, and those are tough tests. The particulates appear to be a loophole in the gasoline engine laws currently.