Tire air pressure estimating apparatus
First Claim
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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Accused Products
Abstract
In a tire air pressure estimating apparatus, wheel speeds of respective wheels are successively calculated when a vehicle is running. At least one of a tire resonance frequency and a tire spring constant is extracted from vibration frequency components included in a wheel speed signal with respect to each of tires. Tire air pressures of drive wheels are estimated based on the extracted tire resonance frequencies or the tire spring constants. Rotational state values (e.g. wheel speed values) of driven wheel tires are calculated based on the detected wheel speeds. Tire air pressures of driven wheels are estimated based on a deviation of the rotational state values of the driven wheel tires.
59 Citations
25 Claims
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1. A tire air pressure estimating apparatus comprising:
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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. - View Dependent Claims (2, 3, 4)
a dividing device for dividing said vibration frequency components into a plurality of vibration frequency ranges; and
a signal intensity calculating device for calculating signal intensities in said respective vibration frequency ranges, wherein said selecting device selects said vibration frequency range from which said at least one of said tire resonance frequency and tire spring constant is to be extracted among said vibration frequency ranges based on said signal intensities calculated by said signal intensity calculating device.
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4. A tire air pressure estimating apparatus according to claim 1, wherein said selecting device calculates vibration input intensity from a road surface to said tires and selects said vibration frequency range based on said vibration input intensity.
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5. A tire air pressure estimating apparatus comprising:
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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;
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, wherein said second tire air pressure estimating device includes a condition determining device for determining whether conditions for carrying out estimation of said tire air pressure based on said rotational state values are satisfied. - View Dependent Claims (6)
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7. A tire air pressure estimating apparatus comprising:
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a wheel 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 plurality of tire resonance frequencies and a plurality of tire spring constants from vibration frequency components of a wheel speed signal with respect to each of wheel tires;
a selecting device for selecting at least one of a tire resonance frequency and tire spring constant used for estimating tire air pressure among said at least one of said plurality of tire resonance frequencies and said plurality of tire spring constants based on a running state of said vehicle with respect to each of said wheel tires;
a determining device for determining, based on said running state of said vehicle, whether said wheel speed signal is suitable for estimating said tire air pressure based on said at least one of said tire resonance frequency and tire spring constant extracted therefrom and selected by said selecting device; and
a tire air pressure estimating device for estimating said tire air pressure based on said at least one of said tire resonance frequency and tire spring constant selected by said selecting device and extracted from said wheel speed signal detected when said determining device determines that said wheel speed signal is suitable for estimating said tire air pressure based on said at least one of said tire resonance frequency and tire spring constant extracted therefrom. - View Dependent Claims (8, 9, 10, 11)
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12. A tire air pressure estimating apparatus comprising:
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a wheel speed detecting device including wheel speed sensors, for successively calculating wheel speeds of respective wheels based on wheel speed signals output from said wheel speed sensors when a vehicle is running;
an extracting device for extracting a tire resonance frequency with respect to each of wheel tires from vibration frequency components included in said wheel speed signals;
a running state detecting device for detecting a running state of said vehicle;
a changing device for changing a frequency band including said tire resonance frequency extracted by said extracting device based on a detection result of said running state detecting device; and
a tire air pressure estimating device for estimating a tire air pressure of each of said wheel tires based on said tire resonance frequency extracted from said frequency band changed by said changing device. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A tire air pressure estimating apparatus comprising:
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a wheel speed detecting device including wheel speed sensors, for successively calculating wheel speeds of respective wheels based on wheel speed signals output from said wheel speed sensors when a vehicle is running;
an extracting device for extracting a tire resonance frequency with respect to each of wheel tires from vibration frequency components included in said wheel speed signals;
a vibration input determining device for determining whether a magnitude of a vibration input from a road surface to tires is larger than a reference value;
a changing device for changing a frequency band including said tire resonance frequency extracted by said extracting device based on a determination result of said vibration input detecting device; and
a tire air pressure estimating device for estimating a tire air pressure of each of said wheel tires based on said tire resonance frequency extracted from said frequency band changed by said changing device. - View Dependent Claims (23, 24, 25)
at least one of a vehicle braking state detecting device, a wheel braking state detecting device and a vehicle turning state detecting device, wherein said changing device means changes said frequency band based on detection results of said respective detecting devices in addition to said magnitude of said vibration input.
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Specification