irenesbob

Interesting quote from an online review of the new Toyota Tacoma's V6:

"The engine also uses both direct and port fuel injection. Toyota also addressed one issue with direct injection -- that the injectors are closer to the spark plug, and therefore more susceptible to carbon buildup. The engine computer calculates when the likelihood of carbon may occur, and initiates a self-cleaning process using the port injection, and high-pressure bursts through a small side opening in the injectors.
You are likely to hear it do that -- it’s a tic-tic-tic sound -- that you may notice every few hours, or every few days, depending on driving habits."

Is this feature performed by Audi’s current engines (I believe not)? If not, could/should it be if Toyota truck offers it?

tenspeed

I have not heard of the feature being used in the Audi engine design. In my opinion, Audi will implement the design when they feel that they are losing sales or when they have to clean up intakes under warranty.

irenesbob

Ah, is that part of the "Vorsprung durch Technik" company ethos?

Acuransx

So what is best way other than use of top tier gasoline to (hopefully) prevent this issue? The transmission in the 3.0T engine is so good at keeping the revs low unless you are driving in anger this engine doesn't get much of a workout. Even when hustling off a stoplight briskly I rarely see over 3000 rpm and the forward velocity is plenty fast. Wondering if need to do the old "Italian tuneup" once or twice a week. Any thoughts greatly appreciated.

newmoon

Toyota has used both direct and port injection, in what they call "D-4S", for quite a while since the 2GR-FSE engine in the 2005 Lexus IS 350.

Audi has put port injection on the latest 3rd gen EA888 4 cyl 2.0 L turbocharged engine, but it is apparently still not included in US models with this engine (I believe the 2015 A3 and 2016 A6).

The Flex-Fuel compatible 2.0T engine in the 2013-onwards A4, A5, allroad and Q5 (but not the A6) does have a 5th port injector, but my suspicion is that it is only used when running on E85 during a cold start. E85 is more prone to condense out of the air at low temperatures, so the 5th injector is needed to overcome this by enriching the mixture beyond the capacity of the other 4 injectors. I did recommend to a Q5 owner who was concerned about carbon build-up to maybe try running E85 in the winter to specifically make use of this 5th injector.

TH3PERFECTON3

Wait what ? So we have 2nd gen of that engine ?
whats improved ?

Fahrer

These are 3rd generation engines but without port injectors. Those are added for European models because of the need to meet stricter emission standards. Port injectors give better mixing during cruising ( majority of running time). The carbon buildup should still be lower with the US market DI engines than earlier engines as Audi now has better control of the crankcase pressure resulting in less oil mist being returned to the intake area and being carbonized. Oil consumption has been greatly reduced in 2012MY and later for Audi engines.

Excessive Oil Consumption Isn't Normal - Consumer Reports

newmoon

The 2016 A6 2.0T has a large power increase to 252 hp, 273 lb-ft
compared to the 2015 with 220 hp, 258 lb-ft.

This article talks about the improvements of the 3rd gen EA888:
Audi Gives Us the Skinny On Its Third-Gen EA888 Turbo Four and the SQ5?s Twin-Turbo Diesel V-6 | Car and Driver Blog

This is a presentation from VW:
http://www.cargroup.org/assets/speak...idt_oliver.pdf

Slide 23 shows the feature modularity of the engine, including the MPI (port injection) and FSI (direct injection).

But then slide 25 shows the intake manifold without MPI injectors for the US market.

Like Fahrer said, the port injectors are primarily to meet stricter Euro emission standards.

James517

I had read that Audi was coming out with the combined direct & port injection so the engine could use what's best at any specific time. Other than the obvious complexity, seemed like an excellent idea....but seems like a lot more plumbing, etc.