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Discussion Starter #1
Here is an example of dual injection direct AND port injection:

http://www.autoblog.com/media/2006/02/Lexus-3_6-3.JPG

"The real story, though, lies just above and below the intake runner. You can see that there are actually two injectors for each cylinder - the top one is a standard port fuel injector, while the bottom one injects fuel directly into the combustion chamber. The two injection systems are used together to optimize the fueling over the engine's operational envelope.
As described in the January 2006 issue of SAE Automotive Engineering International, the system primarily relies on the port injection system when low engine speeds are combined with high loadings. Under these conditions, a direct injection scheme cannot properly atomize the fuel, and so approximately 60% of the fuel is provided by the port injector. As engine speed increases, the direct injection system takes over more of the fueling responsibility, until eventually it provides 100% of the necessary go-juice. Obviously, there some complex calculations going on to determine the optimum fueling over the engine's operating range, and that has led to over 300 patents being issued to Toyota concerning the design of this system.

There's a 7% increase in HP and 7.5% increase in torque from the system, some of which comes from the 11.8:1 compression ratio that's enabled by the use of direct injection. Better yet, the benefits apply to the entire powerband, so this is a feature that will be useful to most any driver.

The dual injection system also reduces cold-start emissions. The port injection system dumps a bit of fuel on the back of the closed intake valve; when that valve opens, the fuel is evenly distributed throughout the cylinder. As the piston approaches the top of its travel, the direct system injects a bit more fuel into the cavity on top of the piston. The total air/fuel mixture in the combustion chamber is slightly lean, but the mixture is significantly richer in the area around the spark plug, making it easier to ignite in a cold engine. The result is quicker warm-up and smoother operation when cold. "


So, once again, a standalone running in tandem with the stock system may prove to be even more beneficial than thought for making HP.

So, in summation, those who say "Oh you can't run port injection in tandem with DI" I say NONSENSE! Its about tuning, thats all it will ever be about. Air and fuel go in, it burns, it makes HP. There is no voodoo, no psychic waves manipulating time/space within the combustion chamber, no shredding of the fabric of the universe for going against the small minds who think its impossible.

This is why I say that a seperate set of injectors run off a piggyback system OR a standalone system run in tandem will give you the BEST bang for buck. You get the extra fuel req'd for big hp AND you get the benefits of DI for cruising and driveability.
 

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So, try it out and let us know what breaks. We are already too rich as it is, and seem to be unable to make it much leaner without fuel cut. Sorry.
 

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Here is an example of dual injection direct AND port injection:

http://www.autoblog.com/media/2006/02/Lexus-3_6-3.JPG

"The real story, though, lies just above and below the intake runner. You can see that there are actually two injectors for each cylinder - the top one is a standard port fuel injector, while the bottom one injects fuel directly into the combustion chamber. The two injection systems are used together to optimize the fueling over the engine's operational envelope.
As described in the January 2006 issue of SAE Automotive Engineering International, the system primarily relies on the port injection system when low engine speeds are combined with high loadings. Under these conditions, a direct injection scheme cannot properly atomize the fuel, and so approximately 60% of the fuel is provided by the port injector. As engine speed increases, the direct injection system takes over more of the fueling responsibility, until eventually it provides 100% of the necessary go-juice. Obviously, there some complex calculations going on to determine the optimum fueling over the engine's operating range, and that has led to over 300 patents being issued to Toyota concerning the design of this system.

There's a 7% increase in HP and 7.5% increase in torque from the system, some of which comes from the 11.8:1 compression ratio that's enabled by the use of direct injection. Better yet, the benefits apply to the entire powerband, so this is a feature that will be useful to most any driver.

The dual injection system also reduces cold-start emissions. The port injection system dumps a bit of fuel on the back of the closed intake valve; when that valve opens, the fuel is evenly distributed throughout the cylinder. As the piston approaches the top of its travel, the direct system injects a bit more fuel into the cavity on top of the piston. The total air/fuel mixture in the combustion chamber is slightly lean, but the mixture is significantly richer in the area around the spark plug, making it easier to ignite in a cold engine. The result is quicker warm-up and smoother operation when cold. "
So, once again, a standalone running in tandem with the stock system may prove to be even more beneficial than thought for making HP.

So, in summation, those who say "Oh you can't run port injection in tandem with DI" I say NONSENSE! Its about tuning, thats all it will ever be about. Air and fuel go in, it burns, it makes HP. There is no voodoo, no psychic waves manipulating time/space within the combustion chamber, no shredding of the fabric of the universe for going against the small minds who think its impossible.

This is why I say that a seperate set of injectors run off a piggyback system OR a standalone system run in tandem will give you the BEST bang for buck. You get the extra fuel req'd for big hp AND you get the benefits of DI for cruising and driveability.[/b]
The biggest difference in that setup is that port injection is the primary method of fuel delivery, and DI is used only in the upper rpms/ high load situations to provide extra fuel. Because the port injection has already added it's fuel by the time the DI comes into effect there will never be a lean condition due to the dual fueling. This is fundamentally different than how our motor functions. Using port injection on our motor would result in extremely lean conditions until the DI added it's fuel to the mix...That would be very very bad... Now if someone could figure out how to basically run our motor off some additional port injectors, and use our DI the same way that Toyota does it we would be fine, but that would involve alot of hacking in the stock ECM or a very capable piggyback/tuner..

Those 300 patents that Toyota has on the system tells me that it's not an easy system to make work, and will probably never happen for us...
 

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Discussion Starter #4
So, try it out and let us know what breaks. We are already too rich as it is, and seem to be unable to make it much leaner without fuel cut. Sorry.[/b]
Uh, thats to be done after you have things like a new turbo, etc..


Now if someone could figure out how to basically run our motor off some additional port injectors, and use our DI the same way that Toyota does it we would be fine, but that would involve alot of hacking in the stock ECM or a very capable piggyback/tuner..[/b]
This is what I am shooting for right now. Since the XEDE and COBB might not work out as planned, I am looking at setting up a MSnS2 to control the port injectors since it has fine enough resolution and runs pretty fast. It is also possible to hook a standalone in as a piggyback to control the DI injectors too. The input into the DI amp is a standard injector signal. ;) Finding that out was an absolute relief because it basically means we can go standalone and control the stock injectors.

I have MS'ed a few cars with great results, some of them I managed to add extra circuits to the MS to keep the stock ECU happy so people could keep their warranty. Thats why I haven't been all that worked up about the XEDE and COBB.
 

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You gotta be one hack of a tuner to play with this... power doesnt blow the engine, tuning does! that said, its possible to blow the engine @ stock power level or less, if you screw up.
 

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So if a major international manufactuer with a 400 million dollar F1 program and sales on damn near every continent can do it then why can't we?!?!?! It's so simple....
 

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So if a major international manufactuer with a 400 million dollar F1 program and sales on damn near every continent can do it then why can't we?!?!?! It's so simple....[/b]
"Obviously, there some complex calculations going on to determine the optimum fueling over the engine's operating range, and that has led to over 300 patents being issued to Toyota concerning the design of this system."

Maybe someone could just look up each of 300 patents. Assuming they are comprehensive, then it's just simple matter of advanced math, chemistry, and physics to piece it all together. Should have it figured out by the time the first-gen hydrogen fusion engines are hitting the market.
 

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Discussion Starter #9
Its used in the 2GR-FSE motor in the IS350

You cant just tack it on though, the engine has to be optimized to use both.[/b]
The ecu is tuned around the engine, not the other way around. ;)

I was going to use the port injectors to merely supply the extra fueling required at high boost levels.

Thats if they are even neccesary. I am going to flowtest the stock direct injectors just to get a baseline, find out the max time the injectors have the opportunity to spray, then I have to do some calculations for flow for boost and compression offset.

I tried to do some calculations and according to some very conservative calcs (spraying only during intake cycle with no overlap) the direct injectors are only capable of supporting about 400bhp. Thats without altering anything but injector pulse. Of course, thats very conservative btw and the only way to tell is to do a flow test for 3 seconds, measure the output volume into open air, and derate it for boost effects. (it sprays into 20psi).
 

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The ecu is tuned around the engine, not the other way around. ;)[/b]
Thats true but, the intake manifold, and piston, head designs are important factors as well.

For port injection:

The intake manifold must be designed so that there is an even air fuel mixture and that fuel does not puddle and has ample time to intermix with the air.

The head design must have adequate quench area, cooling, combustion chamber geometry to minimize knock and maximize cylinder filling with the air/fuel charge.

The piston design should be of lower compression in the case of a boosted vehicle. They should have minimal protruding edges and areas where hot spots could cause a problem.

In Direct Injection:

The intake manifold just has to flow air.

The head design is optimized for the filling of air without regard to fuel mixing. It is designed for statified charge combustion which is unique to DI.

The piston design is higher compression and is oddly surfaced to encourage statified charge combustion and fuel mixing within the cylnder itself. The combustion takes place in a toroidal cavity on the piston's surface. It is not optimized for homogenous charge combustion in the case of port injection.
 

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Discussion Starter #11
The piston design is higher compression and is oddly surfaced to encourage statified charge combustion and fuel mixing within the cylnder itself. The combustion takes place in a toroidal cavity on the piston's surface. It is not optimized for homogenous charge combustion in the case of port injection.[/b]

Our car does not do charge stratification. That is evident from the service docs. Just look at the injector pulses: there is only one pulse per event. Stratification requires 2 per event.

In actuality, port injection does a better job of homogenization of fuel with air. Yet another plus.

And there are plenty of 10:1 engines with alot less engineering kicking out higher numbers, so I doubt tuning will be the big issue.
 

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Our car does not do charge stratification. That is evident from the service docs. Just look at the injector pulses: there is only one pulse per event. Stratification requires 2 per event.

In actuality, port injection does a better job of homogenization of fuel with air. Yet another plus.

And there are plenty of 10:1 engines with alot less engineering kicking out higher numbers, so I doubt tuning will be the big issue.[/b]
Don't mean to be a smartass, since you obviously know much more than I do about this topic. But I remember what I've read pretty well and Google is a beautiful thing. This is not specifically about our engine but I think it outlines features common to all DISI's: http://media.ford.com/article_display.cfm?article_id=9705:

Under traditional technology, the air-fuel mixture inside the cylinder can’t deviate very much from the optimum 14.7:1 ratio of air to fuel. In particular, air-fuel mixtures that are too lean simply won’t ignite.

DISI engine technology uses so-called stratified charging to overcome this limitation.

With DISI, the spark plug is surrounded by a relatively small, precisely shaped volume of ignitable air-fuel mixture that results when fuel is sprayed toward the spark plug just before ignition. Only the area directly around the spark plug, at the top of the cylinder, contains air-fuel mixture. Other areas inside the combustion chamber merely contain air or recirculated exhaust gas.

This stratification of the charge allows the new DISI engine to burn mixtures with a much higher rate of air than conventional lean-mix engines. With the Ford DISI engine, the fuel-air ratio can increase to 60 parts of air (instead of 14.7) for every part of fuel.

The cushion of non-combustible gas around the combustion chamber also means that less combustion heat has to be evacuated. This improves the thermal efficiency of the engine.

Fuel is injected into the cylinder. The shaped piston crown guides the air/fuel mix to the spark plug.

As the spark plug fires, igniting the mixture, surrounding areas contain only air or recirculated gases, forming an insulating cushion at the cylinder walls and cylinder head.

Another factor contributing to improved fuel economy is the ability to increase the compression ratio from about 10:1, as is normal, to approximately 11.7:1 without the need for premium fuel, because direct injection reduces the tendency of engine knock. The higher compression ratio alone increases efficiency by about two percent.

The DISI charge stratification process works best at low and medium loads in the lower half of the engine speed range, where traditional gasoline engines are least efficient.


Thanks for prompting me to find that article. It's interesting stuff and I understand it a little better for having read it again.
 

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Ghettospeed you obviously have your mind made up and no amount of arguing will change your mind. Just go slow ans try not to blow stuff up.

Few points to consider:
And there are plenty of 10:1 engines with alot less engineering kicking out higher numbers, so I doubt tuning will be the big issue.[/b]
The CR alone means nothing, your combinding 2 different fuel sources, there will eb tuning issues to work out especially when you have so many factors as you do with our ECU.

The ecu is tuned around the engine, not the other way around.[/b]
I guess this is true in a sense but you cannot just throw any euc onto any engine. And when an ECU is deisnged to run 1600 psi ijectors you cannot just throw 100<psi injectors in with it and epxect it to be happy.

I tried to do some calculations and according to some very conservative calcs (spraying only during intake cycle with no overlap) the direct injectors are only capable of supporting about 400bhp. Thats without altering anything but injector pulse. Of course, thats very conservative btw and the only way to tell is to do a flow test for 3 seconds, measure the output volume into open air, and derate it for boost effects. (it sprays into 20psi).[/b]
I would like to see your math and what you base it on and how you justify it as conservative.

How do you justify 20 psi as open air pressure for your injector baseline?

Lasty I am still ocncerned at using port injections ass an add on, if the DISI is responsible for even 50% of your fueling needs then that means your port injectors intorduce a lean air fuel mix into the combustion chamer until the DISI adds its fuel, How will you prevent this lean mixture from igniting?
 

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Discussion Starter #14
Well, if DISI *is* doing charge stratification, it does not show what is normally required of charge stratification ie double pulses, unless they are considering the peak and hold feature of the injectors a sort of effort at stratification. If so, its quite primitive and from the gas mileage most of us get, its not very effective.

I will look at the scoped waveform again to verify that the hold current does not undergo some sort of modification in relationship to the peak pulsewidth.

I guess you *could* call it "charge stratification", but, in actuality its a very primitive method if this is true.

Conservative means:

1) calculated for injection only turning intake stroke

2) Total time for injection event is done at max rpm of 8000rpms (essentially, pressure * time = volume) Less time means that the flowrate will be lessened. The volume of fuel required for a particular boost level (20psi) must be maintained even at the shortest event (max rpm). Our cars even fully boosted and tweaked probably won't need or see over 8krpms.

2)20psi is the pressure inside the chamber at max boost. That 20psi lowers the pressure differential between the injected fuel and the medium into which it is injected. That affects the overall flowrate.
 

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How is 20 psi the pressure inside the chamber at max boost? If inlet boost is 15 PSI how does it magically get to 20 psi. If your looking at the pressure after compression then your way off because ti is compressed 9.5 times thus 20 is not even close! I still think your numbers are off... and you still have not addressed the lean condition with aux port injectors...
 

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Discussion Starter #16
How is 20 psi the pressure inside the chamber at max boost? If inlet boost is 15 PSI how does it magically get to 20 psi. If your looking at the pressure after compression then your way off because ti is compressed 9.5 times thus 20 is not even close! I still think your numbers are off... and you still have not addressed the lean condition with aux port injectors...[/b]
The more boost you have, the less the differential pressure across the injector nozzle, therefore the less fuel is injected per event. 20psi is used because it is a "worst case" scenario to account for a slightly modded engine. More boost = less fuel flow into the cylinder.

There is NOT a "lean condition" merely because of port injection, thats why it hasn't been addressed. If that was inherently true, then every boosted motor with port injection would be blown up by now. You simply add the required amount of fuel and you have "addressed" the "lean condition".
 

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Keep in mind that if you want the injectors to inject at times other than BDC during the compression stroke you are gonna have to add the compression pressure to the equation too.

so given the chamber pressure at Worst Case scenario= (1 atmosphere + Boost) multiplied by the compression ratio.

So 15 psi plus 20 psi of boost = 35psi

35psi x CR (9.5)= about 332psi at TDC.

The pressure differential at Top Dead Center is 322 psi.


The lean condition I suspect he is talking about is the period between where the port injected air/fuel enters the cylnders and the period where the DI injectors inject the fuel.

Depending on how much fuel you add the inital air/fuel charge entering the cylnder is going to be explosively lean and prone to compression ignition becuase the DI have not yet added the fuel required to richen the mix in this gap period.
 

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The crappy conservative stock tune is most likely the biggest contributing factor to the poor gas mileage we get with this car...its kinda like running around with your check engine light on all the time...lol
 

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a lot of you are poking holes and citing articles that refer to the disi engine under it's normal operating conditions so adding port injection to the mix makes no sense but if you look at it from ghettospeeds context at higher rpms and boost where starvation may become an issue, those normal operating conditions no longer exist and stratified charge characteristics are not desireable anymore because fuel economy isn't the goal in this case.

This came from the Sport Compact Car review on the MS6.

"The exhaust note is well tuned inside the cabin, but from the outside sounds like a linebacker exhaling through a cocktail straw--backpressure in D flat. Engineers hinted the engine endured extended bouts with more than 15.6 psi during testing with no ill results; a stiffer block, forged crankshaft and steel connecting rods offer proper credentials.

There is certainly power to be had from uncorking the exhaust. But once power figures start growing, the issue of whether the aftermarket can meet the challenge of a necessary bump in fueling, given the complexity of the ultrahigh-pressure direct-ignition fuel system, remains. In a direct injection engine, the injectors can only fire during the compression stroke vs. constantly in an engine with port injection, which may explain some of the softness we felt after 6000 rpm as injectors struggled to inject more fuel in less time.

Our best advice is to use conventional auxiliary injectors in the manifold for added fueling once beyond the capacity of the DI system. Combine those with a front-mount intercooler and larger turbo and you'll have a legitimate powertrain capable of serious numbers."


view original thread here: http://forum.mazda6club.com/index.php?show...c=51302&hl=


view scc article here: SCC website
 

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Im not saying the article is wrong... but I would just like to note that SCC is the biggest ricer publication known to the universe. My $0.02
 
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