Heating, ventilation, and air conditioning unit for automotive vehicles

An automobile heating, ventilation, and air conditioning unit, comprising:

• a heating, ventilation, and air conditioning case permitting flow of interior air;
• an evaporator core disposed in said case for air cooling air;
• a heater core disposed in said case downstream of said evaporator core for heating the cool air to produce warm air;
• an air mix chamber defined in said case for blending the cool air with the warm air;
• an air mix door disposed between said evaporator core and said heater core for controlling a percentage of the cool air and the warm air being fed into said air mix chamber, depending on a position of said air mix door;
• a foot-vent communication passage defined in said case by partitioning a rear end of said air mix chamber by a partition wall extending substantially vertically along an inner wall of said case so that said foot-vent communication passage communicates with a downstream end of said air mix chambers,
• wherein said case has foot vent outlets at a lower end of said foot-vent communication passage and has a rear vent outlet in close vicinity to said foot vent outlets;
• and
• a rear vent passage defmed within said case so that said rear vent passage communicates with an air-delivery passage between said evaporator core and said heater core and extends back and forth at the bottom of said case;
• wherein said case has a rear vent outlet at a rear end of said rear vent passage, and a lower end of said heater core enters partly into said rear vent passage to form a heat exchanger for a rear passenger compartment independently of a heat exchanger for a front passenger compartment, and said case has a bypass passage defined below said heat exchanger, and
• a mode-select door located in close vicinity to said heat exchanger for controlling a percentage of the cool air flowing through said bypass passage into said rear vent passage and the warm air flowing through said heat exchanger into said rear vent passage.