I've had a co-worker that had to pay for the decarbonization on his Volkswagon. It's definitely an issue with direct injection engine. How much of an issue is disputed.


But the fact that Ford is switching to the dual injection system, if true, makes me wonder. They aren't doing it for fun, and I don't know of any other significant reasons to switch to port and direct over just direct, and it's definitely more expensive and complicated.

 

Supposedly the carbon deposits are not an issue on the EB engines due to the turbos and the way the exhaust gases are forced out, thus not allowing any carbon to build up on the intake valves. It's basically a non-issue.

As far as the dual injection setup, I'm guessing it gives Ford much better control over fuel, allowing them to use port for when it is beneficial and direct for when it is beneficial. I think port is cleaner on startup, and quieter at idle. It allows them to have the advantages of both injection types, plus the ability to deliver enough fuel for the high HP engines.

I'm sure they aren't doing it just to say they can...

 

Lexus dual fuel system helps increase fuel economy as well. Basically don't use DI if you don't need it, therefore not running a high pressure mechanical pump (parisitic loss)

As well as being able to really tweak fuel tables to maximize efficiency


ETA link:http://www.enginelabs.com/news/new-l...kinson-cycles/

 

The early VW FSI engines were bad about developing carbon on the valves. They were one of the first main stream DI engines and had a really dirty PCV system. The later TSI engines are better much better. Some of their latest engines also use dual injectors. This is becoming more common on new cars.

 

I've seen the beast with my own eyes! The 3.5 gen 2 on display at the Cleveland auto show has both direct and port injection!
However the display says it is the "high output" version.

 

My 2010 LS460L had both port and direct. Lexus has similar carbon buildup issues with early direct injection applications. They went to dual injection in order to fix the issue.

Not sure why Ford didn't do this to begin with considering the known issues with direct injection. I don't believe carbon buildup is not an issue for these engines. My seeing plenty of discussion on ecoboost forums about it. Ford going through all the trouble and expense to add port injection now, just like other manufacturers did when they had carbon buildup issues, seems like a fix, not a feature.

 

"Exciting new feature" is sometimes Marketing speak for "fixes a problem that plagued the last generation." Just about everyone who galloped straight to direct injection ran into issues with carbon buildup. This new engine should not only solve that problem, but be pretty sweet too.