Smoke Control

[907DAVE]

Is it just a function of the MFD map?

Or is it the Low Boost Fueling map, PW, etc.?

What is the most efficient way to reduce smoke?

[cleatus12r]

Is it just a function of the MFD map?

Or is it the Low Boost Fueling map, PW, etc.?

What is the most efficient way to reduce smoke? Leave it stock. :hehe:

Poor (or less than highly efficient) combustion efficiency and the amount of fuel per amount of air are big contributors.

If your program is designed to give you a certain PW at a certain RPM/APP/ICP (obviously there is no map for this, but it all comes out in the wash ;) ) then one fix is to command less PW (multiplier) at that certain RPM/APP/ICP.

Increasing ICP will result in less commanded PW (unless the PW map has been changed...not the PW multiplier map) because the PCM will account for a mass fuel desired difference with the higher ICP and automatically lower the PW.

The low boost fuel maps are a MFD limit. They limit the actual MFD desired to whatever the value is for a given MAP vs. RPM. If you were to lower the low boost fuel to say, "30" across the board, you'd get a total MFD of 30 and have a gutless pig.

Setting the LBF map to an acceptable range while driving like a normal person (it would take some trial and error) and only allowing higher MFD under really high boost conditions would help.

:hmmm:

[907DAVE]

:hmmm: <---- thats a good one, thats what I am like everytime I think about this stuff.:giggle:


If you use the PW Multiplier, it appears you can only reduce PW about 1ms at operating temps. Is that enough?

Or is that value not MS?

More like PW X 1.5 or whatever?

[cleatus12r]

It's a multiplier.

It "basically" takes the desired PW for a given ICP/MFD (in the pulse width map) and multiplies it by the value in the multiplier.

So by all rights, you can either jack up the values in the straight pulse width map to reflect what you want the PW to be for a given MFD/ICP that is not based on EOT so you can really churn out the powah upon first startup on a -10F day........

OR

You can calculate (within fairly close reason) what the actual PW will be if you do some math. The PW multiplier map allows injection pulse width changes based on EOT instead of just allowing a ton of fuel while the engine is cold.

[907DAVE]

So to simplify things a guy could change the PW map to get desired results on a warm engine, then do a little math and apply those changes to the multiplier map? Or would it be just as easy to do this with the multiplier?

[cleatus12r]

You know, for aftermarket injectors that flow significantly different from stock (especially those with larger nozzles) that's probably the direction I would take. Either that or just leave the multiplier map alone and just drive normal until the engine is warm. The base PW map should be changed anyway for large injectors just to get the idle right.

[907DAVE]

Whats the deal with the Adder to PW multiplier?

[cleatus12r]

Well, in it's stock form, the "adder" becomes a "subtractor" to cut back pulse width at high boost levels. "Defueling" anyone?

It starts cutting .1 (I assume ms) at 14.5 PSI at 1400 RPM.
At max, it cuts .7 ms (again assuming) at 23.2 PSI at 2600 RPM.

Some tuning changes that all to "0" so no fuel subtracting is taking place.

[907DAVE]

Could this map be used as an opposite, like subtract (PW?) at low boost?

Or is that what the LBF map is already doing indirectly?

[907DAVE]

Here is an interesting post Charles made on the Nation a while back.




Can you go too lean? As much as we all got a kick out of poking fun at the wizzer on his glorious "lean out" run....

Over the past year or so I have noticed something, and I've made reference to it a few times before. If you pull fuel, you MUST pull timing/icp all else constant. It goes WITHOUT FAIL in my truck, that a simple drop of say 1ms of pw, will result in utter violence from the engine, and the sound of advanced timing. At one point recently I was down to 0 degrees of timing, and 2200psi at WOT just to try and stop it. Couldn't be done. The engine was NEVER happy like that. Running clean as a whistle, and making probably mid 500's, but very, very noticeably less happy.

Back when I was running Jonathan's stuff without alteration on my own, I always noticed that the "hot" file would ALWAYS be much, much smoother than the midrange program. Just smooth as silk in the full on program leaving smoke as far as the eye could see, and rough and ragged in the midrange program running clean as a whistle, and making 50 or so less hp. Working with him on those files a bit, I know for a fact that the ICP/Timing was the same on them.

That taught me two things....

First, more fuel will "soften" an engine out once you crest the smoke limit.

Secondly, less fuel down low will light the FUK out of a charger. As was the case, where my midrange program would blow the tires off just nailing the throttle at times, and zip right up, while the "hot" program would smolder, and smolder and finally light off. Smooth, but sluggish.


Those are basic facts of life with a diesel IMO. Too much fuel at spoolup.... and you get bad sluggish response. Too little fuel after spoolup, and you get ragged, unhappy performance.... that I have NO doubt would kill and engine in short order if left unchecked.



So............. why?

Well, since I can't crawl inside the cylinder and see for myself. All I can do is hypothesize (figured I demonstrate correct usage )

IMO, the spoolup issue is simple. You inject too much fuel and you put the fire out, and get smoldering sh*t going down the line to try and light the charger. Rpm won't come up, power won't come up, and you've got nothing to spin up the charger but cold smoke. That one's easy....

As to needing more fuel up top at full power...

Here's what I've gathered to date. If you think about the likely scenario playing out in the cylinder, you have fuel being injected, heating, begining to burn, and once the burn commences, it can easily burn rather quickly if the stage is set appropriately. Far TOO quickly if you don't watch your ***.

If you just shoot a tiny little spurt of fuel in the cylinder, it will start to burn, and then flash off rather quickly without much issue. No real pressure to speak of, and no real power either because the BMEP will be very low considering the limited crank angle through which it exerted good cylinder pressure. Okay fine. We'll call this a mild program.

So what if you inject say, twice that much fuel now. Well, now you've got the same flashing off, except there is twice as much fuel once it starts to flash, and the injector has also turned off about this time, so there's no more cold fuel (relative to the cylinder temp) being injected that needs a moment to heat before combusting. So? BAM! It all just pops, and flashes off reeeeal quick. When I get in this range with my truck, I call it "crispy". You have to REALLY watch your *** here. A bit too much of ANYTHING and you can create some scary cylinder pressures with modest fuel quantities, and as I said, insanely LOW timing/ICP values. Obviously pulling enough timing would stop it, but now you're pissing away power, and creating heat with this all flashing off late.

So? Add twice again more fuel...... And it STOPS!

That's right. Dowse it down with fuel, and the "extra crispy" bs stops. Immediately, WITHOUT FAIL.

I personally believe this to be due to the fact that you have a constant flow of incoming fuel that will not ever allow the fuel to "flash" off and "round the corner" where it's still in the meat of the cylinder temperature/pressure (near TDC) when you cut the injector off. If you turn the injector off while it's still flashing hard the fuel pocket just EXPLODES, and tried to send your heads into the hood. You can feel it if you've played with timing and cylinder pressure a bit. It is not good.

Trying to pull fuel has proven to be IMPOSSIBLE for me. The only way to calm the truck is to pull boost. That allows me to alter the burn RATE, not the quantity/time. And as such, I'm not really sure how to make good power, without smoking and not be putting extra stress on the engine.

I'm going back to laying fuel down on the ground at WOT and using water to control the EGT.

We'll see.


But I ABSOLUTELY believe that too little fuel/ too much air can and will cause very substantial problems for a diesel engine in certain scenarios.

I see it everyday. If you start burning every drop of fuel, you better make sure you've got the tune SPOT-ON, or I expect you would hurt things in a hurry.




And mattr66's version



what happens to a cutting torch when you go from the proper flame and start taking away the acetelene while leaving the oxygen flow the same.........POP!




Very interesting stuff..........but is defiantly throws a stick in my spokes.:hmmm::D

[cleatus12r]

Dave,

I have personally experienced this on many occasions and I really began to notice it on a stock fueled truck with a slightly "smoothed" base SOI map. Dropping ICP in the "advanced" regions quieted it down.

To be completely honest with you, I was actually looking for that exact post a few days ago.

[907DAVE]

Well I have been working on making my Daily program smoke free. It was pretty good but I was experiencing excessive smoke on a 50-60 mph "roll on". I was able to get it juuust about completely smoke free by dropping PW in this certain area of the map.........:woot:.

Problem now is at lower speeds, parking lots, driveways, etc the truck will slowly pick up speed and then launch forward without changing the APP. Basically when I am trying to maintain a slow speed the truck will accelerate quickly without me asking it to. Prior to making these adjustment the truck behaved PERFECT, besides the smoke.

Another issue I created is a 150 RPM rolling idle.:hmmm:

Here is what the map looks like.........

http://i619.photobucket.com/albums/tt274/907dave9/ProblemPW.jpg

I tried adjusting the ICP map to lessen the "ramp up" with seemingly no change.

My only guess now is I am having an ICP issue, maybe compensating for such low PW.

Did I go too far with the PW map?

Should I be making my adjustments somewhere else?

Be easy on me......I am new.:)

[thedieselguru]

Dave,

As I understand it, part of the issue is timing. The other part is to atomize the fuel. In that, if you advance timing then you can burn fuel that isn't "broken up" as well. But if you retard timing, you have to really atomize the fuel for complete burn.

The example being HPCR systems. The closer to TDC you SOI, the higher the rail pressure and vise versa. In a HEUI, the ICP and intensifier piston accomplishes what rail pressure does in those systems. Controls injection pressure at the nozzle.

All that being said, I would think that a lower ICP and a little advance in SOI would make less smoke without the "lean burn" feel. With a bump in PW to keep the fuel delivery the same.

But I might be way off base???

Roger

[907DAVE]

Well my issue is that I am running injectors that are roughly 3 times as big as stock injectors, and can deliver this fuel in about half the time. Because of the faster delivery rate I do not want to add any more timing to reduce smoke. The other part of the problem lies in the injector nozzles being so large, I loose atomization, and the only way to get this back is to increase ICP. I am not sure how to add any more ICP without any negative side affects, like I am experiencing now.:cheesy smile:

[907DAVE]

Damn it.........I think I finally realized what I did wrong.

If I quit thinking about it then all of a sudden it pops into my head.:doh:

[cleatus12r]

Damn it.........I think I finally realized what I did wrong.

If I quit thinking about it then all of a sudden it pops into my head.:doh:


It's funny you mentioned that. I was going to give you a "pop quiz" based on the questions you asked in the previous post.

ALL RIGHT!!!

[thedieselguru]

Well don't keep us in suspence, man?

[907DAVE]

Actually I realized that in that particular program I was a little more aggressive with the Base SOI map in the light throttle ranges.

I switched back to a program with the same PW map with the easier timing curve and the slow speed issue went away but.............I still have the rolling idle.:hmmm:


Sooooo quiz away..........pleeeaaassseee.:cheesy smile:

[cleatus12r]

What is your minimum IPR duty cycle parameter? What is commanded in the base IPR map? What effect does the ICP have on your PW?

[907DAVE]

Min IPR Duty% Parameter is 4.98%

Duty Cycle Maps says should be around 4.5% @ level 20 on the Regulator Flow (which I am not sure what that really is).

As PW drops ICP goes up.........right?

[thedieselguru]

Just to be curious, what's the fuel pressure in heads under load? Those injectors have got to tax a lift pump pretty hard.

[907DAVE]

Fuel pressure is not an issue as I am pushing close to 140 gph @ 60 psi through the heads at all times.:yikes2:

[thedieselguru]

That's a bunch

[907DAVE]

You are right! It uses a 5/8 pickup tube to the pump/filters then 1/2 all the way to the engine where it splits to 3/8 to feed the rear of each head.

[907DAVE]

Well after taking yet another look at the PW map it appears I took close to .3 MS away from my Idle range..........I added that back and might give it another try tonight.

I just cannot wrap my head around what that actually did to my ICP/IPR%.:hmmm:

[cleatus12r]

This damn laptop. I had 3 paragraphs written and it thought that it needed to do an automatic "go back to previous page" action...... I need another piece of duct tape over the touchpad. I thought that these things were only supposed to work with a finger touch; not shadows, shirt sleeves, moving air, etc.

Anyway, the condensed version goes like this.....

The injectors do have a mechanical threshold that doesn't allow them to inject any fuel at .4-.5 ms. of commanded pulse width. Judging by the map you posted, you might be pretty close to that and you might be losing some efficiency.

What is your actual IPR DC % while all of this is going on. I suspect that you may be at about the minimum 5% duty cycle....but with dual IPRs you SHOULD be able to dump ICP at 5% so that is a moot point.


Dave, I'm uncertain of what is going on. You absolutely NEED an emulator so I will send you mine when I get to Georgia so you can get all of your issues fixed quickly instead of doing the tune-test-repeat cycle over and over (since I know that that portion of the tuning is the most frustrating because it takes 10 minutes per tune to do it).

By the way, the XP disk should be arriving one of these days too. I sent it yesterday.

[907DAVE]

Funny because I posted this morning but I guess it didn't stick.:shrug:

At idle Duty% seems to float around 7%-8%, so I dont know if that is causing me any issues.

Cody, is the .4-.5 ms limit on the injectors because of the delay in the PCM to IDM communication then the actual mechanical delay in the injector itself?

What is even more interesting (to me) is that while cruising the PW is typically around 1ms @ +/- 1200psi, so in reality is the injector is actually on injecting fuel for .5ms.

Well what I did was return the PW in the Idle range to where it was before, then use the MFD map to pull additional fuel from the specific ranges I was experiencing the smoke. Seems to work very well now, very minimal smoke, much more stable idle, and the Cruise Control is MUCH happier now.:woot:

Still needs some more tweeking on but I am inching closer. Now if I could just get the Converter Duty% figured out.:D

Thanks again.:thumbs up yellow:

[907DAVE]

Well its back to the drawing board..........

With a few more minor adjustments truck was behaving perfect. Almost no smoke under 3/4 throttle, shifting was good, power was good......... until today.

I was attempting to cross the highway which was very busy, my turn came so I stabbed the pedal and nothing. Ohhhh crap, luckily I made it across unscathed but definitely not acceptable. I did some experimenting on my ride home and it was just in the sub 1500 range that there was no power, ease into it and you would never know anything was wrong.

I am unsure what I took too much away from, but I think it is the MFD map..

Maybe there is no cure for these injectors, but I will keep on trying.

[907DAVE]

Can you please explain exactly how the ICP is increasing when you decrease PW. I just cannot see how it is happening, even though I know (well think) it is.

Also, what happens in the ICP map when MFD is higher than 47 mg/ Stroke.

[907DAVE]

Also, what happens in the ICP map when MFD is higher than 47 mg/ Stroke.

Ok......now I am just going crazy. One program has a limit of 37 and another has it up to 70...............:hmmm:

I am in over my head.:doh:

[Power Hungry]

Dave,

Can you chat for a minute?

[907DAVE]

Sure......Gameroom?

[907DAVE]

Thanks for you help Bill!

Things are MUCH better now.

[Power Hungry]

Glad I could help. Sometimes you just need to bounce ideas off someone. :)

[907DAVE]

True.

I sometimes need to take a step back when things get too deep.:crazy:

[907DAVE]

Bill was spot on.....

I am happy as a clam, or as Bill would say, happy as an oyster.

I FINALLY got this thing working almost perfect. It took alot of reworking and fine tuning of the ICP map, but boy did it make a difference. I also revamped the PW map that resembles the stock one. The truck behaves like it has stock injectors with a 80-100hp tune under 3/4 throttle and is nearly smoke free under hard acceleration. Above 3/4 throttle you better hold on.......... it rips. Scary thing is that I am only asking for about half of the fuel the injectors can deliver.:evillol:

This tune was designed to be my DD program, with the power of a Hot program while being smoke free. With some light tweaking of shift points it will be perfect.

Now I am off to the Tow program.:rofl:

[cleatus12r]

Glad to hear it, Dave. I'm really glad that Bill was able to get you where you needed to be.

[GTS]

I hate to keep pulling up old threads but I keep reading and the more I read the more questions I have. This being a 4 page thread brings up a lot of tops that bring up even more questions! Here are some of the questions I have reading through this thread.

Well, in it's stock form, the "adder" becomes a "subtractor" to cut back pulse width at high boost levels. "Defueling" anyone?

It starts cutting .1 (I assume ms) at 14.5 PSI at 1400 RPM.
At max, it cuts .7 ms (again assuming) at 23.2 PSI at 2600 RPM.

Some tuning changes that all to "0" so no fuel subtracting is taking place.

Bill did a live tune on my truck a bit over a year ago. In looking at my "street" tune and my max tunes the street tune has this table all "0ed" out but my extreme tune has this table reducing the PW. This seems backwards to me. Is there a reason Bill would do this?

What did you and Bill discuss that ended up solving your issues? I’m planning on building a similar program to what you are describing. I’m going to take the Street tune Bill wrote for me that is low smoke and try to dial the rest of the smoke out of it while maximizing power.

[907DAVE]

Bill did a live tune on my truck a bit over a year ago. In looking at my "street" tune and my max tunes the street tune has this table all "0ed" out but my extreme tune has this table reducing the PW. This seems backwards to me. Is there a reason Bill would do this?

What did you and Bill discuss that ended up solving your issues? I’m planning on building a similar program to what you are describing. I’m going to take the Street tune Bill wrote for me that is low smoke and try to dial the rest of the smoke out of it while maximizing power.

Maybe that was just his way of cleaning up the top end a bit.

The biggest improvement I made to help control the smoke was all in the ICP map. I needed to ramp up pressures much faster, and it worked VERY well. But, if you decide to do this, drop your base SOI map down a few degrees in the lower MFD range. Also, dont get crazy right off the bat with this, work your way up to it, too much - too soon can cause some drive ability issues.

[GTS]

Cool, thanks for the input.

On the ICP/PW front I was thinking if I had it set at what ever ICP and PW I needed to get the idle I want I would start there. As I give throttle input have the PW raise first up to the desired max PW, say 2.5 or 3ms. Then from there just have the ICP do all the up and down to make the desired power. That way I'm always as peak ICP for the power level I'm looking for.

I don't know if that's a good way to go about it or not. Am I off base here? Or on the right track?

[907DAVE]

There is a lot more going on there than I will care to comment on, but the way I see it, you have it backwards......sorta.

I think you are better off getting ICP up to max ranges then start stacking on PW.

For instance, my ICP is about tapped at around 1/2 throttle, then PW picks up from there.

[GTS]

Ok that makes sense. I was just thinking being the ICP has by far the biggest range the PW would max out pretty quickly then the ICP would take over from there. But I think you're right on having the ICP ramp up first.

[strokeorcroak]

My lord Dave, what have you got me into.

Just read this entire thread and now im going to go back through and re-read, i could read this 10x and never get alll the info!