Energy for in-tire use is generated from the load induced reciprocating deflection of the tire inner walls above the tire-to-road contact patch adjacent to the shoulder of the tire. This energy is used to power in-tire monitoring electronics. For pulsatile energy generation with capacitive capture, the capacitor is optimally selected in real-time as a function of pulse width to maximize energy capture, or as a function of the pulse-captured energy. The resulting energy pulses are also used to measure the time duration of the contact patch from which the contact patch length is determined thus providing real-time tire geometry and, with tire pressure, real time tire load and, with temperature, tire air molar content. The loads on all tires provide real time vehicle mass and mass distribution. For electrical energy generation, magnet-coil, piezo-electric, and other power conversions are applicable. For non-electric energy generation, fluid bellows, rotary pump, and other power conversions are applicable. Further, run flat tires are designed with a cutout to accommodate and protect electronic devices mounted on an inner surface when running flat.
RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application Ser. Nos. 60/398,492 filed 25 Jul. 2002; 60/413,394 filed 24 Sep. 2002; 60/444,797 filed 3 Feb. 2003; 60/476,606 filed 7 Jun. 2003; and pending U.S. patent application Ser. No. 10/143,312, filed 10 May 2002, all of which are incorporated herein by reference in their entireties.
An energy harvester is provided for converting an input force into electrical energy and also allowing for energy to be stored and then released at a later time. The energy harvester includes a receiver, energy collector, converter, and holder, and operates in three stages. The receiver receives the input force and the energy collector is moved by the receiver with an input displacement. The energy collector is then held in a catch position. The input force changes direction, and the energy collector is released by the holder and moves with an output displacement that is different from the input displacement. The converter generates electrical energy from the motion created.
A tire assembly with integrated power generation features includes one or more piezoelectric devices configured to generate electric charge therein upon being subjected to mechanical strains associated with flexure of tire or wheel components. The piezoelectric device may be incorporated in a variety of tire structures and in many different locations. In pneumatic tire structures, the piezoelectric device and related electronics may be embedded in crown or sidewall locations among such selected components as the exterior tread portion, first and second steel belts of a belt package, carcass, cap ply portion, inner liner, zone base, etc. The piezoelectric device with optional rubber casing may also be attached to such locations as the inner liner and tire exterior. Piezoelectric devices may also be integrated with a tire and safety support combination that is configured to operate in an extended mobility mode when the tire structure loses air pressure. Piezoelectric devices may alternatively be integrated with a non-pneumatic structurally supported tire such as one including a reinforced annular band, a plurality of web spokes extending transversely across and radially inward from the annular band, a mounting band at the inner end of the web spokes and a tread portion disposed on the annular band.
