Air intake passages for automobile heating and air conditioning systems have been known since the advent of climate control systems for passenger compartments of automobiles. With the growing popularity of vans and other vehicles with larger-than-standard passenger compartments, there is an increased need to provide climate control systems which will efficiently control the climate in the larger passenger compartment.
While it has been known that a larger air flow through a climate control system will increase the efficiency and rate at which a system can process, and thus control, the volume of air in the passenger compartment, attempts to increase the air flow into climate control systems have had limited success. The application of the principle of achieving a more efficient heat exchange by increasing the air flow to practical use for a motor vehicle passenger climate control system has not been an easy matter. In large part, this is because the spatial constraints of the application do not lend themselves to simply increasing the cross-section of the intake passage.
Other prior art approaches to increasing air flow have included providing additional entries into the intake passage of the vehicle climate control system. For example, Japanese Patent 58-101813 to Yamashita provides a second door 17 to an inlet 18, which door is interlocked to a door 2 of another intake 1. This approach merely provides two doors in the same plane of the housing wall, requiring a larger cross-sectional area to be available in that plane.
In contrast, U.S. Pat. No. 4,802,405 discloses three free-circulated air openings in three different walls of its system casing, but each inlet requires control by a separate damper door. U.S. Pat. No. 4,779,672 similarly discloses a system having two recirculation air inlets, each of which is provided with its own damper door, with corresponding control mechanisms.
French Patent 2,556,289 discloses a mixer box for a vehicle interior heater which provides for selective mix of partial recirculation air which comes entirely from window openings provided in a single wall.
U.S. Pat. No. 4,676,272 generally exemplifies an air flow control passage also not dedicated to the problem of increasing air flow of recirculated air into a vehicle climate control system. Similarly, the system of German Patent 3,421,323 discloses an air distributor which does not address increasing air flow of recirculation air into a system by multiple entries in different walls of the casing.
As will be seen below, the multiple entry air intake passage of the present invention provides a simplified design for increasing air flow while simultaneously eliminating the need for extra doors and door actuating mechanisms, in turn providing savings in cost and size.