Lean burn mode rules 64.8mpg

[pgfpro]

naturalextraction

You said you ran two engines with great success. What did you do to run these engines at these lean A/F ratios?

I've run two engines at the 18:1 to 21:1 just fine and maintain some levels of usable power in both a motorcycle and car.

[naturalextraction]

I'm sure your knock sensor is working fine. With my studies under the right conditions with all the variables in check I to saw no pre detonation "knocking" or signs there of. However, with the variables off even a little, it was obvious to pre-detonation at even 6lbs psig. I was able to run 25 lbs psig with 30deg timing advanced with no retardation under boost. I also machined a Holset turbine to a Schwitzer compressor housing to get the AR combinations I wanted to match my needs related to turbine spin under lean conditions. If you have a ball bearing center housing for the connecting shaft that seems to work as well depending on the AR of the turbine housing. This is partly to the contribution of high A/F ratio and continued combustion. I also meter my fuels through the inlet side of the turbo. My key words in all of this related would be dissociation, surface tension and change of state. We run an R&D in this area for hopes of providing a simplified means to modify the ICE for both stationary and automotive ICE's. We at some point will patent the methodology and the fuel extraction devices related to extraction of energy from the fuel prior to as in part to the induction and metering system. Your parameters for control are wide as I looked back at the link. I would say your ECM is a good system. Be very pleased with your results and find the happy medium for your cruze conditions and enjoy the mileage gain. Obviously under boost you have to richin the mixture regardless to gain more work from the cylinders under pressure. It's important for sure that you keep your cylinder temperatures low. To run back to a lean condition after pumping hot air (even with an inter cooler) may show quicker signs of pre-detonation. You've exceeded most any mileage gains with the available fuels and with your system you've optimized it's efficiencies to this point. Be happy! Maintaining consistency and providing reasonable drive ability is a great accomplishment. BTW, good header wrapping and thermal insulation's throughout help immensely.

[pgfpro]

Originally Posted by naturalextraction

I'm sure your knock sensor is working fine. With my studies under the right conditions with all the variables in check I to saw no pre detonation "knocking" or signs there of. However, with the variables off even a little, it was obvious to pre-detonation at even 6lbs psig. I was able to run 25 lbs psig with 30deg timing advanced with no retardation under boost. I also machined a Holset turbine to a Schwitzer compressor housing to get the AR combinations I wanted to match my needs related to turbine spin under lean conditions. If you have a ball bearing center housing for the connecting shaft that seems to work as well depending on the AR of the turbine housing. This is partly to the contribution of high A/F ratio and continued combustion. I also meter my fuels through the inlet side of the turbo. My key words in all of this related would be dissociation, surface tension and change of state. We run an R&D in this area for hopes of providing a simplified means to modify the ICE for both stationary and automotive ICE's. We at some point will patent the methodology and the fuel extraction devices related to extraction of energy from the fuel prior to as in part to the induction and metering system. Your parameters for control are wide as I looked back at the link. I would say your ECM is a good system. Be very pleased with your results and find the happy medium for your cruze conditions and enjoy the mileage gain. Obviously under boost you have to richin the mixture regardless to gain more work from the cylinders under pressure. It's important for sure that you keep your cylinder temperatures low. To run back to a lean condition after pumping hot air (even with an inter cooler) may show quicker signs of pre-detonation. You've exceeded most any mileage gains with the available fuels and with your system you've optimized it's efficiencies to this point. Be happy! Maintaining consistency and providing reasonable drive ability is a great accomplishment. BTW, good header wrapping and thermal insulation's throughout help immensely.

Thanks again!!!

That's another great read. I have learned a lot from your threads and you have open my mind to some cool ideas. Very much appreciated.

[greasemonkee]

Originally Posted by naturalextraction

While droplet size from modern day injectors are quite small, in a hot chamber they still can create pinging or complete detonation damaging pistons or valves. Thus why engineers developed DPI for better fuel distribution with higher fuel pressures. Other factors that create anomalies from injected engines would be pump pressure consistencies due to possible voltage drops at pump, restrictions, fuel density changes due to ambient temperatures, to name a few.

I have to ask here, you seem to be suggesting that droplet sizes influence autoignition events. Is this anomaly a result of the lack of latent heat of evaporation due to excessive size or something on a chemical level that only a chemist would understand?

Also, would you agree that detonation frequently occurs at lower, non-audible levels even in most factory engines?



Having been exposed to the world of ricepower, I believe to have achieved a moderate gain in economy by running fuel ratios leaner than stoichiometry. A drop in EGT's was evident, however, the best I could do was around 37 mpg straight hwy. This was a B18C1 with its rather large quench pads and unshrouded valves. I imagine the largest disadvantage was the terrible 5th gear. Eventually the same engine was fitted with turbo apparatus, large injectors, intercooler, and the usual paraphernalia for wasting petrol in the 1320'. What's interesting is that city and hwy mpg's decreased by about 3 mpg and when the engine would tolerate 16.5ish fueling in it's previous naturally asphyxiated form, it now prefers a tad richer and must idle at roughly 12.5:1 air/fuel. I've chalked this up to be the fault of Lucas type injectors.

So my hats off to you Mr. pgfpro for achieving numbers like that, although I am discouraged after reading your post about the B18B engine which is soon to be my next tuned and economy only guinea pig. I think an unorthodox compression ratio and an altered intake valve closing may be of benefit.

[naturalextraction]

[QUOTE=greasemonkee;123571]I have to ask here, you seem to be suggesting that droplet sizes influence autoignition events. Is this anomaly a result of the lack of latent heat of evaporation due to excessive size or something on a chemical level that only a chemist would understand?

Also, would you agree that detonation frequently occurs at lower, non-audible levels even in most factory engines?[/QUOTE

Re: first question: Droplet size is = to volume of fuel per disbursement. Injector pulse by design will allow X # of fuel count based on fuels and densities presumably controlled by pump pressure. There is an ideal state for this liquid fuel and type of injector to measure the amount of fuel at X pulse rate with a particular displacement design. However there are inconsistencies based on fuel conditions and additives, ambient temperatures, atmospheric changes etc. Many who are watching fuel consumptions closely will note that fueling at certain stations provide less or more gains regardless of the season. All gasoline have additives of different types depending on time of season and their own methods of fuel conditioning. As to auto ignition, as stated before, chamber temperatures referencing latent heat are but a particular condition effecting the fuels ability to burn at X rate. Changing of state is expansion of course and our ECMs are to help control the anomalies of fuel, ambient and internal pressure changes and temperatures etc as you know. So yes to your second question. Gasoline fuels in this case are different and have inconsistencies from one station to another and one state to another. Some fill ups will have obvious changes to mileage as not so to others. Changes to controls as from OBD2 to our most recent control systems are always improving to maintain higher efficiencies both in power and economy and to compensate for anomalies. However it has always been the goal to maximize control thus effecting efficiency. Better design of engines and their components add to this efficiency.
My only comment in relation to your system and gains achieve would go back to the availability of programing or remapping the system with the appropriate components to meet the demands of the remapping. Having wider parameters of operation to meet the anomalies related will help to achieve vehicle operation at higher A/F ratios. I've run across only a few systems that can achieve this.
I have to add this note: A friend of mine worked on the Honda Indy team and they would make their own fuel blends. Out of curiosity he took home some to use in his wifes Acura to see how it would perform. Performance was only slightly better but the mileage gain was 3+ per gallon. ( I don't remember the exact number but it was over three) That's significant for only changing the fuel. He's an accomplished engineer and has good methods of testing for consistency and thus I believe his findings.

[pgfpro]

Originally Posted by greasemonkee

I have to ask here, you seem to be suggesting that droplet sizes influence autoignition events. Is this anomaly a result of the lack of latent heat of evaporation due to excessive size or something on a chemical level that only a chemist would understand?

Also, would you agree that detonation frequently occurs at lower, non-audible levels even in most factory engines?



Having been exposed to the world of ricepower, I believe to have achieved a moderate gain in economy by running fuel ratios leaner than stoichiometry. A drop in EGT's was evident, however, the best I could do was around 37 mpg straight hwy. This was a B18C1 with its rather large quench pads and unshrouded valves. I imagine the largest disadvantage was the terrible 5th gear. Eventually the same engine was fitted with turbo apparatus, large injectors, intercooler, and the usual paraphernalia for wasting petrol in the 1320'. What's interesting is that city and hwy mpg's decreased by about 3 mpg and when the engine would tolerate 16.5ish fueling in it's previous naturally asphyxiated form, it now prefers a tad richer and must idle at roughly 12.5:1 air/fuel. I've chalked this up to be the fault of Lucas type injectors.

So my hats off to you Mr. pgfpro for achieving numbers like that, although I am discouraged after reading your post about the B18B engine which is soon to be my next tuned and economy only guinea pig. I think an unorthodox compression ratio and an altered intake valve closing may be of benefit.

Thanks greasemonkee for the kind words!

I need to give some more details on my Honda engine.

This D16 is what we call a Vitara build.

Its a D16Z6 with a set of 75mm YCP Suzuki Vitara replacement pistons with Eagle HP rods.

This brings the compression down to 7.4:1 with a .030"HG

I'm still running a standard bore with a ton of piston to cylinder wall clearance. The ring gaps are also very wide compared to stock, for turbo high boost reasons.

My goal is to run a different turbo(Garrett T3/TO4E 57 trim) with a ramhorn manifold that will make around 450whp and run high 10's in the 1/4 mile.

Of course this will be done on race fuel VP C16.

My goals for this project.
50+mpg
450WHP
10 second ET's
$6000.00 or less invested

So my next test is to disconnect the charge pipe and run it as a N/A engine to make sure the engine is not getting help from the turbo.

I'm pretty sure the turbo isn't doing anything at this point but this test will prove me one way or another.

[greasemonkee]

[QUOTE=naturalextraction;123582][I][QUOTE


Thanks for that explanation; it gives me something to ponder over.




Pgf pro, are those those vitara pistons cast pieces? Wow! 7.4 static CR is moving me back to the old flathead days. Boost dependency?

[pgfpro]

[QUOTE=greasemonkee;123881]

Originally Posted by naturalextraction

[I][QUOTE


Thanks for that explanation; it gives me something to ponder over.




Pgf pro, are those those vitara pistons cast pieces? Wow! 7.4 static CR is moving me back to the old flathead days. Boost dependency?

Yep they're cast with a thermal ceramic coating.

I never did get to mess with any flat heads. But it would be fun.

[pgfpro]

OK, all you guys that are running a lean burn engine. When you go into lean burn do you have to give it more throttle as in a loss of power type feel?

I had my engine up to 23:1 A/F but notice its wanting to lay over at this level.

At 19:1 to 20:1 its fine but as soon as I go to 21:1 or over the engine requires more throttle. Plus I tried moving the timing all around and it didn't make a difference.

I'm starting to think I just hit the lean burn wall with this combination.

I'm going to do some more testing tomorrow because the weather is suppose to be a lot cooler and maybe that will help.

[greasemonkee]

I was playing with a d15z1 last week and I noticed it required considerably more manifold pressure to maintain constant speed or accelerate. This should be the rule, plus you eliminate some pumping loss by having the throttle closer to 100%.

As a safety precaution, I would definitely limit pressure columns up to around 650 mbars in that super lean mode. I normally transition back to stoichiometry at around 600-650 mbars as seen in table below.

My ugly, fuel wasting low cam target:



This same engine when NA did much better running lean oddly enough, hence the mild 15.2 target.


Have you considered finding a straight, constant grade and traveling it while shifting the timing gradually (as well as afr) to find the lowest injector duration that you can achieve? I would graph out the data (provided Neptune can do graphs) and see if there are any trends on the same section of road at the same speed every time. If you had an economy meter (or something to juggle the data and spit out a relative mpg in the software?), you might could go by that possibly?

Just be sure to hold your IAT's constant, among other variables, to make it easy on you, but you probably are well aware of the concept.