Autoignition Threshold Theory
Autoignition Threshold Theory
(OP)
For a turbocharged engine:
What is the relationship between the knock threshold and air pressure? My question is related to running the maximum amount of boost on pump gasoline. I know that as air temperature increases, so does the tendency for engine knock. Independent of temperature, does increased pressure lead to engine knock? For example, say you are running a pressure ratio of 3:1, but it is intercooled down to ambient temperature, would the limiting factors for knock (ignition advance,compression ratio,ect) be the same as for a normally-aspirated engine? Is there any data on this subject? Thank you.
What is the relationship between the knock threshold and air pressure? My question is related to running the maximum amount of boost on pump gasoline. I know that as air temperature increases, so does the tendency for engine knock. Independent of temperature, does increased pressure lead to engine knock? For example, say you are running a pressure ratio of 3:1, but it is intercooled down to ambient temperature, would the limiting factors for knock (ignition advance,compression ratio,ect) be the same as for a normally-aspirated engine? Is there any data on this subject? Thank you.





RE: Autoignition Threshold Theory
Increased pressure, even if the temperature is constant, will make knock more likely. I cannot point you to any specific data. Some data is definitely out there in technical publications by organizations like SAE or the Combustion Institute.
j2bprometheus
RE: Autoignition Threshold Theory
Note that this chart should vary greatly with response to engine specific combustion dynamics.
RE: Autoignition Threshold Theory
There, read the chart near the bottom.
RE: Autoignition Threshold Theory
http://naca.larc.nasa.gov/reports/1946/naca-tn-1131/naca-tn-1131.pdf