*3.1. Subjective Weighting Method*

In this method, the levels of importance were set by experts in the field. According to these experts, the same importance was given to consumption (50%) and emissions (50%). Regarding emissions, the importance was also distributed equally between NOx (33. 3%), CO (33. 3%), and HC (33. 3%). According to this, the weights of SFC, NOx, CO, and HC result in w1 = 0.5, w2 = 0.1 6, w3 = 0.1 6, and w4 = 0.16, respectively.
