Apparatus for the automatic filling of motor vehicle tires

A compressor-free tire-filling apparatus for a motor vehicle having tires pressurizable with a fluid, said apparatus comprising:

• a source of a fluid under pressure in the form of a cylinder containing a variable supply volume of the fluid;
• respective pneumatic valves for said tires actuatable to control an internal tire pressure thereof and connected between said source and the respective tire;
• an electronic controller provided with inputs representing an actual pressure of said tires and at least one driving condition including vehicle speed, vehicle loading, road conditions and terrain, and determining setpoint pressures for said tires, said electronic controller having an output for operating said valves;
• and
• a control element connected to said source for increasing and decreasing a variable volume for said apparatus, thereby matching internal tire pressure to a setpoint pressure therefor as determined by said controller.

A tire-filling apparatus for a motor vehicle having tires pressurizable with a fluid, said apparatus comprising:

• a source of a fluid under pressure;
• respective pneumatic valves for said tires actuatable to control an internal tire pressure thereof and connected between said source and the respective tire;
• an electronic controller provided with inputs representing an actual pressure of said tires and at least one driving condition including vehicle speed, vehicle loading, road conditions and terrain, and determining setpoint pressures for said tires, said electronic controller having an output for operating said valves;
• a control element connected to said source for increasing and decreasing a variable volume for said apparatus, thereby matching internal tire pressure to a setpoint pressure therefor as determined by said controller;
• a system of fluid lines between said source and said valves;
• and
• another valve connected to said lines, operated by said controller and enabling ambient air to be drawn into said system to compensate leakage therefrom and replenish a significant pressure loss in a tire.

A tire-filling apparatus for a motor vehicle having tires pressurizable with a fluid, said apparatus comprising:

• a source of a fluid under pressure;
• respective pneumatic valves for said tires actuatable to control an internal tire pressure thereof and connected between said source and the respective tire;
• an electronic controller provided with inputs representing an actual pressure of said tires and at least one driving condition including vehicle speed, vehicle loading, road conditions and terrain, and determining setpoint pressures for said tires, said electronic controller having an output for operating said valves;
• a control element connected to said source for increasing and decreasing a variable volume for said apparatus, thereby matching internal tire pressure to a setpoint pressure therefor as determined by said controller;
• a system of fluid lines between said source and said valves and said system is operable as a closed system disconnected from the ambient atmosphere;
• replaceable fluid pressure cartridge;
• and
• a further valve operated by said controller and connecting said cartridge to said system upon detection of a critical filling state of said system, whereby said closed system is automatically restored to a setpoint filling state.

A method of operating a tire-filling apparatus for a motor vehicle having tires pressurizable with a fluid, comprising the steps of:

• a) measuring an internal tire pressure at each of said tires;
• b) determining at least one operating condition of the vehicle;
• c) logically combining measurements of internal tire pressure and information with respect to an operating condition of such vehicle to determine a setpoint pressure for each of said tires;
• d) generating a pressure exclusively by displacing a piston in a cylinder for increasing and decreasing variable volume;
• and
• e) applying the pressure generated in step (d) to each of said tires until said setpoint is reached or venting excess pressure from each of said tires until said setpoint pressure is reached.