What's the minimum thickness you should allow from bowl edge to piston od?

[COMP461]

Stop Greg, your killing me. Was this before or after they realized there was a problem?

It’s simple; the papers give you the tools, or parameters to go by to achieve the best combustion efficiency. You come on here like you have some sort of ax to grind, you not dealing with uneducated people here, and you can’t pull the wool over our eyes. We are out here doing it, pushing the extremes; the group is a collection of people that have race together for years in one of the toughest class in existences. John has done a phenomenal job tuning, and now is a part of this brain trust. There is a lot to come in the future. The surface is just being scratched with diesels. The diesel world will see a lot of innovation mirroring the development in the gas world

 

[JOHNBOY]

I've dealt with Mahle on the issue with the Cummins piston design, like I said, oddly enough they went back to a 146* pattern on the cone angle with a micro-blind nozzle with the 6.7l. I agree with a few ex-Bosch engineers about the cone angle issue with the wider bowl, they could not understand why it was designed that way. A perfect example to see if something doesn't work, is if a company after spending countless hours of design time and a large budget, abandons the idea to go back to what they were doing before. Ever notice how you can take the main event completely out of the bowl and have EGT's in excess of 1800*'s and have no failures, yet use the narrow cone angle and contain both events and have failures at much lower peak cylinder temperatures?

So you talked to Exergy.

I understand your reasoning with "but Cummins changed thing". But those engines run at max rpm of less than what we run our stuff at. The Mustang leaves at around 3500 and never drops below 4500 after that during a pass. My truck is the 4000+ range a good hook. Cummins never included that kind RPM in there parameters IMHO. It is hard to why they do stuff for sure. Just look at the head. After all these years you would think that could get one to flow some air.:bang

Response to the part in blue.
Yes. I talked to you about tightening up the injection spray angle what 2 years ago? Tightening helped some. But again it is a paradox. You stop killing the lip but the dome starts to hate you.

One thing I wonder is the heat really different between the two? Or is one showing more heat on the probe because the charge has less distance to travel to the probe so less time to cool. You can have as many have found, have heat and no smoke, burn the heck out of pistons with low measured egts, and have high smoke and EGTs never hurt a piston.

 

[Smokem]

Yes. I talked to you about tightening up the injection spray angle what 2 years ago? Tightening helped some. But again it is a paradox. You stop killing the lip but the dome starts to hate you.

I deal with Exergy a great deal, more than just talking to them. Realize what you just said about tightening the pattern and having issues with the piston dome. Then realize that altering the pattern changes the swirl direction of the flame when taking the point of contact from the wall to the dome. Seems like this entire thread has turned into a paradox.

 

[Devan Manis]

Comp, could you kindly direct us to where these ASE papers could be found? Although I do think you mean SAE.