Microprocessor based air inflation control system

A system for adjusting the air pressure in automobile tires and other inflatable devices comprising:

• a source of pressurized air;
• normally closed inflation valve means having an inlet connected to said source of pressurized air and an outlet connectable to an inflatable device for inflation thereof;
• normally closed vent valve means having an inlet connectable to the inflatable device and an outlet for venting the inflatable device;
• pressure selector means manually operable by a user of said system for selecting a desired air pressure for the inflatable device;
• pressure sensing means for sensing the actual air pressure in the inflatable device;
• comparison means for determining the pressure difference between the desired air pressure and the actual air pressure;
• first valve control means responsive to said comparison means determining that the desired air pressure exceeds the actual air pressure by at least a first predetermined amount for opening said inflation valve means for an inflation time interval having a duration which varies in response to the magnitude by which the desired air pressure exceeds the actual air pressure, to cause air to pass from said source to an inflatable device connected to said inflation valve means and responsive to said comparison means determining that the desired air pressure exceeds the actual air pressure by at least a second predetermined amount, greater than the first predetermined amount, for opening said inflation valve means for a time interval substantially less than that required to increase the measured actual air pressure to the desired air pressure to avoid inadvertent overfilling of the inflatable device in the event initial connection of the inflation valve means to the inflatable device has resulted in an erroneously low reading of actual air pressure;
• second valve control means responsive to said comparison means determining that the actual air pressure exceeds the desired air pressure by at least a third predetermined amount for opening said vent valve means for a vent time interval, to vent air from an inflatable device connected to said valve means inlet;
• and
• means for operating said sensing means and said comparison means upon closure of said inflation valve means or said vent valve means at the end of an inflation time interval or a vent time interval.

A system for adjusting the air pressure in automobile tires and other inflatable devices comprising:

• a source of pressurized air;
• normally closed inflation valve means having an inlet connected to said source of pressurized air and an outlet connectable to an inflatable device for inflation thereof;
• normally closed vent valve means having an inlet connectable to the inflatable device and an outlet for venting the inflatable device;
• pressure selector means manually operable by a user of said system for selecting a desired air pressure for the inflatable device;
• pressure sensing means for sensing the actual pressure in the inflatable device;
• comparison means for determining the pressure difference between the desired air pressure and the actual air pressure;
• first valve control means responsive to said comparison means determining that the desired air pressure exceeds the actual air pressure by at least a first predetermined amount for opening said inflation valve means for an inflation time interval having a duration which varies in response to the magnitude by which the desired air pressure exceeds the actual air pressure, to cause air to pass from said source to an inflatable device connected to said inflation valve means;
• second valve control means responsive to said comparison means determining that the actual air pressure exceeds the desired air pressure by at least a second predetermined amount for opening said vent valve means for a vent time interval, to vent air from an inflatable device connected to said valve means inlet;
• means for operating said sensing means and said comparison means upon closure of said inflation valve means or said vent valve means at the end of an inflation time interval or a vent time interval;
• and
• accessory control means for controlling operation of an accessory device and manual switching means capable of alternatively assuming a first position in which said comparison means, said first valve control means, and said second valve control means are enabled for operation while said accessory control means is inhibited and a second position in which said comparison means, said first valve control means, and said second valve control means are inhibited while said accessory control means is enabled for operation.