Dear all,
I am trying to understand the calculation of the HBEFA4 emission module and came across a few questions:
- According to a previous discussion (https://github.com/eclipse-sumo/sumo/issues/15206), SUMO takes emissions for a particular
vehicle class and emission type from the database and fits it over a range of speed and acceleration. The different colored lines in the attached graphs correspond to seven discrete acceleration values. SUMO then takes f[0] to f[6] to calculate the emissions
for a particular vehicle class. Are the coefficients f[0] to f[6] thus the average value of the seven different colored lines?
- HBEFA which is not dependant on acceleration is compensated by taking its dependency on road slope. As far as I understand, SUMO calculates the added acceleration it needs to exert
to overcome the road slope. One documentation (https://sumo.dlr.de/doxygen/d2/db0/_helpers_h_b_e_f_a4_8h_source.html) (line 113) states the calculation of a2, which takes the
vehicle acceleration and then adds it with (gravity * sin θ). I could not find this calculation step on another documentation page (https://github.com/eclipse-sumo/sumo/blob/7308a1b9569b4fc8edc99c891063b4366a31d0a8/src/utils/emissions/HelpersHBEFA4.h#L114).
Is it already embedded in another function for the second documentation or is there another reason behind it?
- Not directly related to the HBEFA4 emission module – but does the angle in the FullOutput (https://sumo.dlr.de/docs/Simulation/Output/FullOutput.html)
refer to the vehicle angle with respect to the road slope? I tried to set up a road stretch with a 0.02 (2%) & -0.02 (-2%) road slope by patching the network with z-coordinates. Since not all models incorporate elevation data (https://sumo.dlr.de/docs/Networks/Elevation.html),
I have also selected the carFollowModel=”KraussPS”. All the angles in the FullOutput remained constant at 90 degrees. Is there an explanation for this result?
Any pointers are appreciated. Thank you in advance!
Warmest regards,
Addina
|
