ronbros3

has anyone ever done ,direct injection on a rotary mazda engine????

the fuel injector in the combustion area,, not in the port,, to many fuel/air variables in port injection!!

Monkman33

iTrader: (28)

It would benefit low rpm smoothness, but it would not benefit higher rpm power. The mixture of air and fuel is achieved better the further away the Injectors are from the combustion chamber. There is a break point of limited or no gains.

Evil Aviator

Curtiss-Wright, John Deere, Avco-Lycoming, and Rotary Power International (defunct).

They were stratified charge engines:

http://protonet.org/doc/rota_text_1986_ltr.pdf

nillahcaz

iTrader: (2)

I told some one about a test i did some time back in PM's
I got the Direct Injection injectors from a lexus IS350 and installed them in the rotor housings right above the B of the 13B cast into the housing and used the old primary as my new secondary. They are parallel to the ground and the injectors have an off set spray pattern, the spray is 36º and is angled down so it functions as if they where mounted 18º inlet side up from horizontal.
I used a 13b-re with S4 NA rotating as it was what i had. It was 3/4 bridge. the primary ports have only half bridge on them the secondary ports are full.
Used 20" primary intake runners and 15" secondary runners and made a TB out of a Quadrajet base plate with out any other part of the carb. this gave me a spread bore progressive TB. part 65 in this photo http://www.gmcmotorhome.com/tech/qje...ebuild_pg4.jpg
shortened a RB header by 6" then collected.
I used an old E6K that the ignition output no longer worked and a buddy built a driver that I have no clue as to how it worked, but it had the 60v fast open spike. It did put a delay into the system that was non linear so it was a bit of a pain to work around
I do not recall the exact pressure it was running but it was high I think it was in the range of 35 bar *500 psi* and was still low but worked out.
fixed timing of 20º with a 9º split. Put down 256 hp but due to a problem never got to fully tune it. got 17/25mpg. throttle response was unbelievable and had a larger useful power band than any BP I had ever seen, but still was far from working the way it should.
I lost all the real documentation for this along with all 15Gb of excel, word and .DXF/NC files i had done for bridge port timing / overlap stuff due to a failed hdd

Chaotic_FC

this is amazing!
i didn't realize that anybody had successfully installed direct injection on a rotary before!

if you were to give any advice, what would you do differently the second time around? I love the idea of a pp on the street for the power, but hate the economy that would come with it. If i could get a direct injection setup working on it i would be one very happy camper.

nillahcaz

iTrader: (2)

If successfully is what you call it I was in sales for way to long. The numbers are good the ride was not.
don't do it the way i did.
I built it out of parts from other tests and did it half *** just to see if it would be something to put money into later. *and some day.... we will see*
Get an ECU that supports DI, This is as big as placement of the injectors.
Know the PSI and flow rate vs. PSI drop rate and if they are rated at full static compression or any other odd things I have seen some weird ones. This is just like boost as compression starts in the engine the flow of the injectors will drop.
Try to get the fuel spray into the air and not spraying down the walls of any thing.
Build it right. build it twice. ok so thats not how its normally said but for the love of god use some scrap parts to play with before changing good ones in a way that you cant recover.
I did see that the chrome was flaking around the injector hole... don't know if this was due to how i drilled it out, welding the inserts in or what but look out for this.
And trust me as good as i made it sound I was still a long way off from wanting to daily with that setup. it may have been the driver for the injectors, it may have been a failing ECU, it may have been a lot of things but expect a full tune to be fun.
and before you ask what the problems where I have no clue. There was a set of spots where there would be a lack of power afr's where ok in when it happened it just would stop making any more power for a quick second then would go and so on felt like a sticky over sensitive wastgate. could not get them to go away, could move them but they never got better. Flooding, no cold\hot start problems at all BUT if you stall it.... good luck.

arghx

iTrader: (3)

You do know that Mazda is working on a form of direct injection for the rotary right now? I think the biggest thing for direct injection is figuring out the proper injector timing and spray pattern. That's tough to do in your garage.

Liborek

Everything was already figured out by NASA, John Deere...more than 20 years ago...with mechanical injection. BSFC was awesome, considering that turbo rotary has around .65+ BSFC, these engines achieved .38 BSFC, even R26B had at sweet spot .46 BSFC... Mazda themselves had direct injection, stratified charge RE, but basically couldn´t put this engine to any car because EGTs at idle were too cold to light on the catalyst (despite emissions of HC compared to conventional RE were reduced by 60% and NOx also by over 60%) It just didn´t fall into category of ICE with working catalyst converter...

notorque

mazda is currently r&d the DI on the next rotary...if they make it who knows. but right now, the e85 powered furai uses DI. they said it gave 30% increase in mileage and 10% more power. DI is much better for nitrous too. less chance of detonation in the runners, i know on the 8 that thing wasnt cheap to replace. happened once to me..never used nitrous again. DI is much easier to tune as well. my buddies cayman s has DI and for some reason, you can tell the difference on the dyno much easier with subtle changes in cycle.

nillahcaz

iTrader: (2)

Umm.... yes, but i do not see how the X16 getting DI helps us running a 13b.

As for the second part, it is just what i said in my second post.
"Get an ECU that supports DI, This is as big as placement of the injectors."
"Try to get the fuel spray into the air and not spraying down the walls of any thing."

The idea is to get the fuel charge into the rotor with out getting fuel on the rotor. keeping the flame front mostly in the dish will also lower stress and heat on the apex seals.

If I recall I was using a timing of 132º BTDC at idle and 200º at 8000 as target for where I had them installed. for Idle i just picked a spot that looked right *real high tech I know* played with it till throttle response was good with a good afr, stable egt, and peak vacuum for redline I found that using the old primary injector location for secondary the timing of the injector pulse did little so I advanced it till afr, EGT, or Hp changed then did the same with retarding the timing and set it dead in the middle of the two. Not the most high tech but it worked.


also Mazda has the injectors on top the engine with there DI setup allowing it to put the fuel charge in the middle of the rotor and to give the fuel time to saturate at high rpm. Due to the porting job, housing design and injector spray pattern I picked a location with a lot more offset. this is the Mazda one.

ronbros3

to add some info to the mix, workin with diesels for 30yrs, increasing injector pressure helped a lot for taking atomization into vaporization process, much smaller droplets= more surface area exposed to oxygen molecules, spray pattern has to vapor the fuel BEFORE it hits a wall of any type.

im guessin fuel press. at 2000-2500psi would be a nice place to start.

ON with the IDEAS!!

nillahcaz

iTrader: (2)

most GDI systems are about 103bar or 1500psi

ronbros3

and modern diesel fuel rail pressures are in the 22,000-25,000psi range , now i bet that would atomize the fuel! so it can turn to a vapor quicker,could be a vapor already,or darn close.

sure would reduce chance of fuel spray impinging on chamber or wall.

and two injectors properly placed could help with swirl and turbulence in chamber ,for a more complete burn in the dead areas.

nillahcaz

iTrader: (2)

there are HUGE changes in the way diesel and gas flow from an injector, At 25,000 psi a gas injector small enough to have good control over the amount needed as well as the fast open voltage would make the cost of not only the injector but the control circuit unaffordable for most who would use them.

ronbros3

yes you are correct,

also the injector would have to be an electronic PIEZO multi phase unit, and the ECU would be totaly unlike any thing on this site!!

gianic

Hello,

Are there any updates here? I am very interesting in a similar project with the 13b.