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An optical fuel level sensor for providing an electronic signal representative of the fuel level within a fuel tank, generally comprising a waveguide body, a photo source, and a photo receiver. The waveguide body can either be of a dual-tapered or single-taper shape and includes numerous tiered face

An optical fuel level sensor for providing an electronic signal representative of the fuel level within a fuel tank, generally comprising a waveguide body, a photo source, and a photo receiver. The waveguide body can either be of a dual-tapered or single-taper shape and includes numerous tiered facets, which are angled surfaces located on the outer periphery of the waveguide. When the fuel level within the fuel tank is above a particular tiered facet, light that impinges that facet will refract out of the waveguide, conversely, when the fuel level is below that facet, impinging light will be reflected back into the waveguide such that it is received by the photo receiver. In this manner, the fuel level sensor is able to utilize the reflected light received by the photo receiver to provide an electronic signal representative of the fuel level. Furthermore, a calibration feature may be included which provides calibration information indicating when the fuel level has reached a known, predetermined level.

대표청구항 ▼

An optical fuel level sensor for providing an electronic signal representative of the fuel level within a fuel tank, generally comprising a waveguide body, a photo source, and a photo receiver. The waveguide body can either be of a dual-tapered or single-taper shape and includes numerous tiered face

An optical fuel level sensor for providing an electronic signal representative of the fuel level within a fuel tank, generally comprising a waveguide body, a photo source, and a photo receiver. The waveguide body can either be of a dual-tapered or single-taper shape and includes numerous tiered facets, which are angled surfaces located on the outer periphery of the waveguide. When the fuel level within the fuel tank is above a particular tiered facet, light that impinges that facet will refract out of the waveguide, conversely, when the fuel level is below that facet, impinging light will be reflected back into the waveguide such that it is received by the photo receiver. In this manner, the fuel level sensor is able to utilize the reflected light received by the photo receiver to provide an electronic signal representative of the fuel level. Furthermore, a calibration feature may be included which provides calibration information indicating when the fuel level has reached a known, predetermined level. mator for estimating pressure of a tire by comparing the plurality of characteristic quantities detected by the detection section. 5. A tire air pressure estimating apparatus comprising: wheel speed sensors for detecting respective wheel speeds of a plurality of wheels; detection sections for detecting, based on the respective wheel speeds of the plurality of wheels detected by the wheel speed sensors, for each of the plurality of the wheels, at least one of: characteristic quantities of the wheel speed signal in a plurality of frequency bands, or a characteristic quantity of the wheel speed signal in a special frequency range, the wheel speed signal in the special frequency range being obtained by processing the wheel speed signal using a frequency-weighted filter which makes gain high at a higher frequency range of the special frequency range; and a tire air pressure estimator for estimating pressures of tires by relatively comparing the respective characteristic quantities of the wheel speed signal detected by the detection section. 6. A tire air pressure estimating apparatus according to claim 5, wherein the tire air pressure estimator compares a difference or ratio between the characteristic quantities of the wheel speed signal with a reference value, so as to relatively compare the characteristic quantities. 7. A tire air pressure estimating apparatus comprising: a wheel speed sensor for detecting wheel speed of a single wheel; a detection section for detecting, based on a wheel speed signal that is output by the wheel speed sensor, a characteristic quantity of the wheel speed signal in a low frequency range including frequency lower than a torsional resonance frequency and a characteristic quantity of the wheel speed signal in a high frequency range which is higher than the low frequency range, a tire air pressure estimator for estimating pressure of a tire by relatively comparing the characteristic quantities detected by the detection section. 8. A tire air pressure estimating apparatus according to claim 7, wherein the tire air pressure estimator compares a difference or ratio between the characteristic quantities of the wheel speed signal in the low frequency range and the high frequency range, with a reference value, so as to relatively compare the characteristic quantities. 9. A tire air pressure estimating apparatus according to claim 7, wherein the characteristic quantities are vibration levels. 10. A tire air pressure estimating apparatus comprising: wheel speed sensors for detecting respective wheel speeds of a plurality of wheels; road surface friction state estimators for, on the basis of the respective wheel speeds of the plurality of wheels detected by the wheel speed sensors, estimating a friction state estimation values, which represent friction states between a tire and a road surface; and a tire air pressure estimator for estimating pressures of the tires on the basis of the friction state estimation values estimated by the road surface friction state estimators. 11. A tire air pressure estimating apparatus according to claim 10, wherein the road surface friction state estimator estimates, as the friction state estimation value, one of: a change in frequency cut off characteristics in a frequency range including frequency lower than a torsional resonance frequency, which is attributable to an increase in ground contact length, in a wheel speed frequency characteristics, and a change in vibration suppression characteristics in the frequency range including frequency lower than the torsional resonance frequency, which is attributable to the increase in the ground contact length. 12. A tire air pressure estimating apparatus according to claim 10, wherein the road surface friction state estimator estimates, as the friction state estimation value, for each of the plurality of the wheels, at least one of: (a) in a transmission characteristics, form road surface disturbance to the wheel speed, approximated to a low order model, a frequency, at which gain changes from a value in a predetermined range to a value out of the predetermined range, in a gain diagram representing a frequency response of the approximated model; (b) a vibration level of a wheel speed signal in a special frequency band; and (c) a vibration level of the wheel speed signal in a special frequency range, the wheel speed signal being obtained by processing using frequency-weighted filter which makes gain high at a higher frequency range of the special frequency range. 13. A tire air pressure estimating apparatus according to claim 12, wherein the tire air pressure estimator estimates the tire air pressure by one of: (1) comparing a difference or ratio between the estimated frequencies, at which gain changes from the value in the predetermined range to the value out of the predetermined range, in the gain diagram representing the frequency response of the approximated model, with a reference value, and (2) comparing a difference or ratio between the estimated vibration levels of the wheel speed signals in the special frequency band, with a reference value; and (3) comparing a difference or ratio between the estimated vibration levels of the wheel speed signals in the special frequency range, the wheel speed signal being obtained by processing using frequency-weighted filter which makes gain high at the higher frequency range of the special frequency range, with a reference value. 14. A tire air pressure estimating apparatus comprising: a wheel speed sensor for detecting a wheel speed of a single wheel; a road surface friction state estimator for estimating a friction state estimation value, which represents friction state between a tire and a road surface, based on the wheel speed detected by the wheel speed sensor; and a tire air pressure estimator for estimating pressure of the tire on the basis of the friction state estimation value estimated by the road surface friction state estimator. 15. A tire air pressure estimating apparatus according to claim 14, wherein the road surface friction state estimator estimates, as the friction state estimation value, a change in frequency cut off characteristics in a frequency range including frequency lower than a torsional resonance frequency, which is attributable to an increase in ground contact length, in a wheel speed frequency characteristics. 16. A tire air pressure estimating apparatus according to claim 14, wherein the road surface friction state estimator estimates, as the friction state estimation value, at least one of: (a) in a transmission characteristics, from road surface disturbance to the wheel speed, approximated to a low order model, a frequency, at which gain changes from a value in a predetermined range to a value out of the predetermined range, in a gain diagram representing a frequency response of the approximated model; and (b) one of a difference or ratio between a characteristic quantity in a low frequency range including frequency lower than a torsional resonance frequency and a characteristic quantity in a high frequency range which is higher than the low frequency range, in a gain diagram representing a frequency response of a transmission characteristics, from the road surface disturbance to the wheel speed. 17. A tire air pressure estimating apparatus according to claim 14, wherein the road surface friction state estimator estimates, as the friction state estimation values, vibration levels of a wheel speed signal in a plurality of frequency bands. 18. A tire air pressure estimating apparatus according to claim 15, wherein the tire air pressure estimator estimates the tire air pressure by comparing the friction state estimation value with a reference value. 19. A tire air pressure estimating apparatus according to claim 16, wherein the both characteristic quantities are vibration levels of a wheel speed signal. 20. A tire air pressur e estimating apparatus according to claim 17, wherein the tire air pressure estimator estimates the tire air pressure by comparing the vibration levels of the wheel speed signal in the plurality of frequency bands. matically displayed via the HTTP applications: wherein the information is displayed via an interface including a window used to display: a current status of a telephone connection between the remote user and a switch, a