Direct Injection Engine

[wapacz]

The thing is it is kind of a less than optimal solution. Putting a secondary injector in the intake has to take out some of the gains that di brings. Just saying there has to be a better way to fix the problem.

Though I'm partial to the idea that the DI engines with higher fuel dilution are the ones getting higher deposits. In other words the high fuel dilution creates more gases and fluids that the pcv must suck up. So getting dilution under control could very well bring the deposit problems down.

 

[JTK]

I wouldn't call Gasoline DI new technology. Isuzu offered a direct injected 3.5L in the Rodeo in 2004. All the gas DI setups I've seen totally eliminated the need for EGR. Idle speeds can be set very low and are so smooth you can barely tell the engine is running. GM is throwing the DI Ecotec in everything now. It's 182hp/6700rpm.

Joel

 

[GMBoy]

This direct injection thread pops up quite a bit around here. I'm not sure the whole truth of the matter yet, but I can share my experience with my 2008 Cadillac CTS with the 3.6DI (304hp). The car now has almost 25k miles (and never back to the dealer yet I might add) and I have done 3 UOA's and they have not shown fuel dilution. As a matter of fact the fuel was less than 0.5 so I see no fuel issues atleast with the GM DI engine. As for the carbon problem, I don't know because the engine has not been apart. But, at every oil change I do run the engine and spray cleaner into the intake so I am cleaning the valves that way. I don't think there is a carbon problem but I always clean my intakes so I do not think I'll have problems even if these engines are prone to build up. My dad has the same car with about the same miles and he never cleans the intake and the car runs great. Again - never any problems with his so I don't know what the inside looks like. Maybe I'll buy a scope with the camera and peek into the engine!

 

[mechtech2]

Oddly, USA versions of DI engines seem to have rich fuel programming, compared to Euro versions.
This has caused fuel dilution of the oil problems, or at least a higher percent of it in the oil.
You'd think the USA would have the leanest and most stringent fuel trims, but it does not. Like I said, it is odd and strange, but exists.
I'd give it time and see how this new engine works out in real life before diving in and buying one. It may be the best thing since sliced bread, but is an unknown at this point.

 

[Shannow]

Originally Posted By: MrHorspwer
As a matter of fact, most gasoline engine have eliminated the EGR valve as VVT allows for controlled reversion of the exhaust though adjustments in cam timing.

EGR contamination on a modern gasoline engine (direct injection included) is virtually non-existant, mainly because there is no EGR valve!


LOL, so this reversion of exhaust gasses doesn't get anywhere near the unwashed inlet valve ?

 

[Jonny Z]

Originally Posted By: mechtech2
Oddly, USA versions of DI engines seem to have rich fuel programming, compared to Euro versions.
This has caused fuel dilution of the oil problems, or at least a higher percent of it in the oil.
You'd think the USA would have the leanest and most stringent fuel trims, but it does not. Like I said, it is odd and strange, but exists.
I'd give it time and see how this new engine works out in real life before diving in and buying one. It may be the best thing since sliced bread, but is an unknown at this point.


Lean burn = higher MPG but higher NOx too, hence the richer trim in the US of A. Cheaper gas here helped that requirement too.

 

[wapacz]

Yep the US hates NOx. It wouldn't surprise me that we have the lowest allowable NOx level in the world.

 

[440Magnum]

Originally Posted By: rudolphna
Originally Posted By: ARB1977
Makes me want to stay away from direct injection engines....although we may be screwed if this is what most or all manufactures will be going to.


All new technologies have teething problems. DI's are fuel dilution, intake valve deposits from the PCV.In time they will be sorted out. Maybe reroute the PCV and create it's own special vacuum pump instead of using the intake.


Aspirator valves to suck crankcase vapors straight into the exhaust, upstream of the catalyst, is tempting. The problem is that downstream of the turbo, there might not be enough pulsation left in the exhaust to operate an aspirator valve.

 

[Shaman]

Originally Posted By: Tornado Red

I haven't had any problems with my Turbo Direct Injection engine

Have you checked your EGR valve, or had vag-com change it's values? Every week on TDIclub is another post about a clogged intake.

 

[Tornado Red]

Originally Posted By: Shaman
Originally Posted By: Tornado Red

I haven't had any problems with my Turbo Direct Injection engine

Have you checked your EGR valve, or had vag-com change it's values? Every week on TDIclub is another post about a clogged intake.

Yes, and yes. As for clogged intakes, these tend to be older TDIs that gradually clogged up over a period of several years. In the past, before ULSD, some folks were having to clean out the intakes every 40k miles or so. Now it can take 200k miles, and if you do it once then you may never have to do it again.

 

[johnd]

Quote:
I wouldn't call Gasoline DI new technology.


Mercedes had a DI gas engine in the 1960's. I remember seeing one on a car show where they mentioned how far ahead of its time the design was.

 

[tangojetta]

This what my TDI intake manifold look like when I cleaned it.

 

[Ursae_Majoris]

Originally Posted By: JTK
I wouldn't call Gasoline DI new technology. Isuzu offered a direct injected 3.5L in the Rodeo in 2004.
Joel

Same engine was in 2003 Isuzu Axiom, also DI. My 2002 Axi has a non-DI version of it. 2003 Axioms had more horses and torque than 2002.

 

[JTK]

Originally Posted By: Ursae_Majoris
Originally Posted By: JTK
I wouldn't call Gasoline DI new technology. Isuzu offered a direct injected 3.5L in the Rodeo in 2004.
Joel

Same engine was in 2003 Isuzu Axiom, also DI. My 2002 Axi has a non-DI version of it. 2003 Axioms had more horses and torque than 2002.


Good call Ursae! I forgot about the Axiom and it's optional DI 3.5L. It's unfortunate that vehicle was ahead of it's time then. Look at # of similar cross-overs on the road today.

Joel

 

[Nick R]

Originally Posted By: tangojetta
This what my TDI intake manifold look like when I cleaned it.

Holy freaking [censored]

 

[Ursae_Majoris]

Originally Posted By: JTK
Originally Posted By: Ursae_Majoris
Originally Posted By: JTK
I wouldn't call Gasoline DI new technology. Isuzu offered a direct injected 3.5L in the Rodeo in 2004.
Joel

Same engine was in 2003 Isuzu Axiom, also DI. My 2002 Axi has a non-DI version of it. 2003 Axioms had more horses and torque than 2002.


Good call Ursae! I forgot about the Axiom and it's optional DI 3.5L. It's unfortunate that vehicle was ahead of it's time then. Look at # of similar cross-overs on the road today.

Joel


Only draw back to Axiom is lower gas mileage, but otherwise it was built like tank. Crash plates underneath were made out of real 2mm thick steel. Plates under engine, center differential and gas tank. By comparison 2005 Toyota Tacoma I used to have had a thin, 0.5 mm plate under the engine and plastic plate under the gas tank.

I still love the styling, adjustable suspension, user-selectable shift points on the auto transmission,Torque-On-Demand (it is a beast built for Alaskan winters), rear LSD, Borg-Warner center differential.

 

[PandaBear]

Originally Posted By: mechtech2
Oddly, USA versions of DI engines seem to have rich fuel programming, compared to Euro versions.
This has caused fuel dilution of the oil problems, or at least a higher percent of it in the oil.
You'd think the USA would have the leanest and most stringent fuel trims, but it does not. Like I said, it is odd and strange, but exists.
I'd give it time and see how this new engine works out in real life before diving in and buying one. It may be the best thing since sliced bread, but is an unknown at this point.


lean burn causes additional NOX, which US categorized as emission but not CO2, but Europe consider CO2 as emission but not as much on NOX. Therefore the rich vs lean issue.

 

[Shannow]

NOx is a driver in photochemical smog, which was prominent in the US some time ago.

Thus the absolute disdain for it in regs.