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Title: KUMSIRL-conversion constant from mass flow to relative air charge Post by: ABCD on July 12, 2012, 04:26:36 AM Hi
Function frame says that KUMSIRL=Vh/2578 How is this formula derived. Thanks. Title: Re: KUMSIRL-conversion constant from mass flow to relative air charge Post by: TTQS on July 20, 2012, 12:48:47 AM The answer is in the ME 7.3.1H Alfa 2.0l BTS in module BGKV 1.30 in the section "Detailed description of function" headed "Physical relationship of the conversion factor" (Page 72 of 1327).
I haven't worked it up because I initially thought it might just be the Universal gas constant (8.3145 J/mol K) * 293.15 K = 2479 which is within 4% of the actual conversion constant value of 2578 assuming SATP (Standard Ambient Temperature and Pressure) conditions then correcting to the funktionsrahmen standard conditions of 273.15 K and 1013 mbar pressure. I guessed you'd get 2578 but it doesn't quite work. Have a look at the attached article "Improved Cylinder Air Charge Estimation for Transient Air Fuel" which gives some further insight into this topic. TTQS Title: Re: KUMSIRL-conversion constant from mass flow to relative air charge Post by: TTQS on July 20, 2012, 12:54:08 AM Function frame says that KUMSIRL=Vh/2578 BTW, it's KUMSRL, not KUMSIRL which is why I couldn't find it in the funktionsrahmen initially ;D TTQS Title: Re: KUMSIRL-conversion constant from mass flow to relative air charge Post by: ABCD on July 20, 2012, 01:22:02 AM BTW, it's KUMSRL, not KUMSIRL which is why I couldn't find it in the funktionsrahmen initially ;D TTQS Thanks for the article. will go through it. My english Function frame says KUMSIRL only. Have attached formula screenshot. Title: Re: KUMSIRL-conversion constant from mass flow to relative air charge Post by: TTQS on July 20, 2012, 08:14:15 AM O.k., I found KUMSIRL in the MED9.1 FR (BGRLFGZS 7.10.0 Calculation of the fresh air charge flowing to the intake manifold). You seem to have a different funktionsrahmen document than those which are posted up here. Please would you upload or otherwise make available the English version so we can all benefit. As things stand, you have an advantage over the people you are asking for help!
Thanks. TTQS |