Motor vehicle air conditioning and heating system with bi-level mode

Claim 1

An air conditioning and heating system for a motor vehicle passenger compartment comprising a casing containing an evaporator and a heater core for receiving air passing from the evaporator, means for controlling heated liquid flow from an engine coolant system through the heater core to control the heat given up thereby, a tempered air chamber in said casing for receiving air passing from the heater core, an upper outlet in said casing for opening said chamber to an upper region of the passenger compartment, a lower outlet in said casing for opening said chamber to a lower region of the passenger compartment, said duct arrangement further including a bypass duct for bypassing air from the evaporator around the heater core to said chamber at a location adjacent said upper outlet, said bypass duct and said upper outlet having co-planar valve seats internal of said casing, and air valve means pivotally mounted in said casing between said outlets for pivotal movement to one position contacting said co-planar valve seats to close both said bypass duct and said upper outlet, said air valve means being further pivotable to another position closing said lower outlet, said air valve means being further pivotable to a midposition opening both said outlets and said bypass duct while forming a barrier between said bypass duct and said lower outlet.