Optimal Speed on Small Gradients - Consequences of a Non-Linear Fuel Map
نویسندگان
چکیده
Consequences of non-linearities in sfc, i.e. specific fuel consumption, of a heavy truck combustion engine are studied. A quasi-static analysis gives valuable insights into the intrinsic properties of the studied problem, i.e. minimization of fuel consumption on small gradients. Two objective functions are shown to give different optimal velocity trajectories on a constant gradient due to non-linearities in sfc. When a constraint is set to keep to a final time, switching between two speeds is optimal. Instead, if consumed time is part of the objective function, in addition to fuel consumption, keeping to one constant speed is optimal. However, the different optimal solutions still show similarities. For a certain significant non-linearity a specific speed range is shown to be unreachable, independent of objective function. Also under more realistic conditions, a dynamic analysis, implemented by a numerical optimizer, confirms that an alternating speed profile is optimal for the case of fixed final time.
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