No direct injection for 2.5

[V8toilet]

I was comparing the specifications of the new Mazda6 to the CX5 on the Mazda website and noticed that the 2.0 liter engine in the CX5 has direct injection and the 2.5 in the 6 has Electronically controlled multiport fuel injection. I wonder why they did that? That can't be good for better fuel mileage.

 

[fthomasr]

I was comparing the specifications of the new Mazda6 to the CX5 on the Mazda website and noticed that the 2.0 liter engine in the CX5 has direct injection and the 2.5 in the 6 has Electronically controlled multiport fuel injection. I wonder why they did that? That can't be good for better fuel mileage.

That's a typo on the website. Google 2014 Mazda6 and you'll see tons of articles that show that the 2.5 is also direct injection.

 

[ngd298]

The 2.5 in the 2012-2013 doesn't have direct injection, the 2014 will. The reason the 2013 and older aren't DI is simply because they aren't Skyactiv engines.

Edit: Nevermind, I see what you are talking about. (spec sheet for the 2014 Skyactiv model) Must be a typo. (yes)

 

[V8toilet]

Could be a typo but I assume nothing this time. Being that it is listed on the Mazda website as such I would say its correct for now. This may change though as time goes by and someone at Mazda catches on. Being MPFI isn't necessarily a bad thing just unexpected knowing it has the same 13-1 compression ratio as the 2.0 and is designed to maximize fuel efficiency. We all know that DI has an efficiency advantage over MPFI but then again I'm no automotive engineer; just someone who knows more than the average Joe about cars.

 

[V8toilet]

The 2.0 liter Skyactive engine operates in Atkinson cycle during part throttle position by holding the exhaust valve open during the compression cycle to reduce pumping losses but still taking advantage of the high compression ratio to some degree during the power stroke. I think this is only possible because of direct injection; the injector releases the fuel after the exhaust valve shuts so it doesn't pump unburned hydrocarbons into the exhaust system. With MPFI I can't imagine how this is possible and therefore with MPFI Mazda is losing part of what it calls Skyative for the engine. With MPFI the fuel is already in the cylinder during the compression stroke because it injects fuel during the intake stroke so if the exhaust valve was held open than some of that fuel would get pushed out into the exhaust system. I've also learned that the disadvantage of DI can be an increase of intake valve deposits due to the fact that the fuel does not wash over the intake valve so the detergents in the fuel cant clean it. The oily deposits can come from the positive crankcase ventilation system recycling blow-by gases back through the intake system. If the 2.5 is a true Skyactive motor with a 13-1 compression ratio than it must have DI and the MPFI is a typo or Mazda has some other trick up their sleeve.

Correction, I was wrong in that in Atkinson cycle the intake valve is held open longer not the exhaust valve so I guess it is possible.

 

[CX-SV]

I expect DI on all gasoline Skyactiv engines.

 

[IHeartGroceries]

I expect DI on all gasoline Skyactiv engines.

Indeed. Mazda pledged some time ago to move away entirely from port injection in all of their new engines.
The Speed6 launched Mazda's first DI engine 7 years ago.

 

[CX-SV]

The Speed6 launched Mazda's first DI engine 7 years ago.

That was early compared to most. What model year did Mazda do DI Speed6?

(Btw-Lexus launched its DI ISx50's as model year 2006)

 

[igotzzoom]

I believe DI enables the 13:1 compression ratio, so I'm almost certain the 2.5 is DI. Must be a typo in the specs.

 

[SapphireHearts]

Since the speed 6 was only 06-07, and they used the same engine...I'm going to say 2006.


Jeff

 

[IHeartGroceries]

The Speed6 officially hit the USDM market in (IIRC) November 2005. It was available overseas several month prior, and suffered a delayed US release.
If you do some careful e-research, it will reveal that Ford EcoBoost is actually Mazda's technology (no, I don't mean FI DI engines), which platooned originally in the MS6, CX-7 and MS3.

 

[deepfriedsushi]

The mazda website has been updated to show that the new 2.5L engine has direct injection for both the CX5 and mazda6.

I noticed this too, so it was a typo on Mazda.

 

[ManMachine]

I have to say the roll out of the information from Mazdausa has been slow and poor.