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Tire air pressure estimating apparatus

  • US 6,385,553 B1
  • Filed: 12/15/1998
  • Issued: 05/07/2002
  • Est. Priority Date: 12/15/1997
  • Status: Expired due to Fees
First Claim
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1. A tire air pressure estimating apparatus comprising:

  • a vehicle speed detecting device for successively calculating wheel speeds of respective wheels when a vehicle is running;

    an extracting device for extracting at least one of a tire resonance frequency and a tire spring constant with respect to each of wheel tires from vibration frequency components included in wheel speed signals which are detection results of said wheel speed detecting device;

    a first tire air pressure estimating device for estimating tire air pressures of drive wheels based on said at least one of said tire resonance frequencies and said tire spring constants extracted by said extracting device, wherein said first tire air pressure estimating device includes a selecting device for selecting a vibration frequency range of said vibration frequency components included in said wheel speed signal from which said at least one of said tire resonance frequency and tire spring constant is to be extracted by said extracting device, and tire air pressures of said drive wheels are estimated based on said at least one of said tire resonance frequency and tire spring constant extracted from said vibration frequency range selected by said selecting device;

    a rotational state value calculating device for calculating rotational state values of driven wheel tires based on said wheel speeds detected by said wheel speed detecting device; and

    a second tire air pressure estimating device for estimating tire air pressures of driven wheels based on deviations of said rotational state values calculated by said rotational state value calculating device.

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