Fuzzy logic for vehicle climate control

Typical automobile automatic climate control systems use linear proportional control to maintain a comfortable interior environment. In the process of refining these systems, we have found two significant limitations of linear proportional control when viewed from the standpoint of an occupant's subjective comfort: 1) there are certain control situations in any HVAC (Heating, Ventilation, and Air Conditioning) system that are inherently nonlinear; and 2) it is not possible to realize occupant comfort merely by maintaining proximity to a desired temperature. In this paper, we describe a fuzzy logic control system which addresses these limitations by including rules that provide nonlinear compensation, and by allowing the control to be expressed in the same heuristic terms that an occupant would use in describing the level of comfort.<>