Why is my oil black?

[Rawze]

(10-14-2019 )LRT1549 Wrote:  Rawze please put some numbers to "high timing advance"...

was referring to programming.

There is no set number, as injection timing is different depending on rpm, fuel amounts, torque being made, how much boost, and about a dozen other factors that are continously in motion while the engine is operating.

- Then there is the factor of EGR. If an engine has EGR gas, then the entire engine will have very different settings. An EGR engine may need 11 degrees injection timing to compensate for the inert gas absorption rate at a specific fuelling, torque, rpm, egr gas flow, and boost, but take away only the egr gas, and suddenly it can barely handle 4 or 5 degrees under the same exact (now missing egr gas) conditions.

Then there are different engines with different compression ratios depending on engine model or perhaps SCR technology and less egr gas, vs an older model that only uses heavy amounts of EGR. Add in all those factors and it gets even more complicated yet.

Then add in pulse injection with common rail engines, or older single injection technologies. - this throws things even deeper into the realm of "what is or is not acceptable".

Now add in the injection strategy ... CDI, PCCI, HCCI, etc... ref: http://rawze.com/forums/showthread.php?t...8#pid19318 - Depending on the type and volatility of injection strategy, some engines may need several degrees of added injection timing to achieve proper mixing (egr gas aside, the older the technology, typically the more timing advance is needed for proper mixing), and in newer technologies, some are so violent in their strategy, such as HCCI, that almost no mixing time is needed at all to get the volatility up to par. In fact, with the latest HCCI strategies, in many cases it can even push the injection timing into negative (post TDC) regions depending on the demand or conditions.


Then there is the power factor. The more power+turbocharging, the more sharply the injection timing has to fall off on a non-egr engine to maintain proper mixing time,.. but on an egr engine, the egr gas itself is heavily changes mixing, so at different power factors, the start of injection curve can even become somewhat flattened, sometimes even being reversed based on how much gas is allowed/needed to meet the requirements at any given point.

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I.E.> The question you have asked there is severely incomplete to be answered correctly.

random quote: "Just because the water is frozen in the lake, does not mean it is only barely below 32 degrees outside".