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sreenathiit12
MemberTraditionally spark ignition engines work with a relative fuel to air ratio of 1 (near the stoichiometric).
I don’t understand the second question.
Related with the wiebe, you must provide the operating conditions (fuel mass, air mass and engine speed) of the engine for each wiebe. If you give only one wiebe these parameters won’t be used. In case that you give more than than 2 wiebes the model will interpolate between them taking account the operating conditions of the wiebes and the operating conditions of the point that is being simulated.MemberThe usual value must be 1. But if you want to increase or reduce the heat transfer you can modify them.
MemberIt is the typical roughness of the steel.
MemberTry to put 5 nodes per duct minimum. Then the mesh size will depends on the length of the pipe.
MemberThen a simple discharge coefficient could be enough. You can change the value for each simulation
MemberA throttle valve can be modelled by a simple discharger coefficient. Do you want to control it during the simulation or it will have a fixed value?
MemberThe values for the gas exchange period are internally defined (C1=6.18+0.417Cu/Cm). You must provide only the values for the rest of the period.
MemberThe coefficients are used to build the injection rate (g/s).
PCR = Rail pressure (bar)
n = engine speed (rpm)
Coefficients A: a (g/s^2) represents the positive slope of the curve at the beginning
a=A1 * PCR + A0
Coefficients B: b (g/s) represents the maximum injection rate.
b=B1 * PCR + B0
Coefficients C: c (g/s^2) represents the negative slope of the curve at the end
c=C1 * PCR + C0
Coefficients D: can be used to shift the pulse and modify the start of injection
SOI = SOP + (D1* PCR + D2) * (6 * n)MemberACT is an alternative. If you use, you cannot impose heat release law. Regarding your data it has no sense an injection pulse with 0 % of mass. 0.5 + 1 is different to 100%. In openwam, the angle for combustion top dead centre is equal to 0. I will check the meaning of the coefficients later. I don’t have the information available in this moment.
MemberACT is an alternative. If you use, you cannot impose heat release law. Regarding your data it has no sense an injection pulse with 0 % of mass. 0.5 + 1 is different to 100%. In openwam, the angle for combustion top dead centre is equal to 0. I will check the meaning of the coefficients later. I don’t have the information available in this moment.
MemberIn the injection pulse tab you can press the button + in order to add a new injection pulse. The information that you must provide is the start of injection and the percentage of fuel mass injected in the pulse. The mass injected by all pulses must sum 100%.
The coefficients that you show are used to build the shape of the injection rate but I need check the exact meaning of each coefficient because I don’t remember. We usually impose the heat release rate and this capability is not commonly used.
MemberThe formulas are writen in latex, but the parser doesn’t work. We are working in a new manual. In this moment if you don’t understand any equation you can copy the latex code and paste in an online latex editor like this http://www.sciweavers.org/free-online-latex-equation-editor
MemberIn this moment it is not possible. The combustion model isn’t very elaborate now and we are working in it. If you want emulate a three injection system, you can use the four wiebes combustion model in order to reproduce each injection pulse.
MemberSorry, but the model is developed to solve compresible flow not hydraulic calucations.
MemberThe code will generate 2 files (***AVG.dat and ***INS.dat). They are ASCII files (Colums separated by tabs) and can be opened with Excel, Matlab, etc …
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