Abstract: A tire pressure monitoring device for a wheeled vehicle that is capable of detecting vehicle motion from the output of a pressure sensor. The device determines from the output signal an indication of the power of the signal, for example the variance of the signal, and detects if the vehicle is stationary or in motion depending on the determined indication of power. The device may determine that the vehicle is in motion if the determined indication of power exceeds a threshold value.

Abstract: A tire monitor for mounting on a wheel rim, the tire monitor comprising a housing having a first part (644A) configured to receive a component substrate (645) and a second part (644B) configured to receive one or more other components of the tire monitor, for example a battery. The first and second parts of the housing are non-coplanar and non-parallel with one another. When the tire monitor is mounted on the wheel rim, the substrate is non-coplanar and non-parallel with a plane (T) that is tangential to the wheel rim at the location where the tire monitor is mounted on the rim and preferably the substrate plane is substantially radial with respect to the wheel rim.

Abstract: A tire pressure monitoring device for a wheeled vehicle that is capable of detecting vehicle motion from the output of a pressure sensor. The device determines from the output signal an indication of the power of the signal, for example the variance of the signal, and detects if the vehicle is stationary or in motion depending on the determined indication of power. The device may determine that the vehicle is in motion if the determined indication of power exceeds a threshold value.

Abstract: An apparatus for measuring parameter values from an electrical input signal comprises a signal sampling device operable to sample the input signal and to produce a corresponding output comprising a measured parameter value; a signal level detector configured to detect changes in the level of the input signal by more than a threshold amount; and a controller co-operable with the signal sampling device and the signal level detector. The controller is configured to operate the signal sampling device to sample the input signal in response to the signal level detector detecting a change in the input signal level by more than the threshold amount.

Abstract: A tyre monitor for mounting on a wheel rim, the tyre monitor comprising a housing having a first part (644A) configured to receive a component substrate (645) and a second part (644B) configured to receive one or more other components of the tyre monitor, for example a battery. The first and second parts of the housing are non-coplanar and non-parallel with one another. When the tyre monitor is mounted on the wheel rim, the substrate is non-coplanar and non-parallel with a plane (T) that is tangential to the wheel rim at the location where the tyre monitor is mounted on the rim and preferably the substrate plane is substantially radial with respect to the wheel rim.

Abstract: A TPM system wheel unit measures rotational period over a number of wheel revolutions, calculates a value of a period of the revolutions and wirelessly transmits the calculated value of the period to a tire pressure monitoring system receiver in the vehicle mounting the wheel. Alternatively, each wheel unit transmits an RF burst of a predetermined length and a received RF burst envelope modulated with a periodic modulation pattern is used to calculate the period of one wheel rotation for each wheel. A central vehicle electronic control unit monitors wheel speed signals for each wheel of the vehicle and calculates a period for the wheel speed signal for each wheel of the vehicle, bounded by a rolling window which may be of variable length. The calculated values are compared and the wheel unit and the wheel location are correlated therefrom.

Abstract: An apparatus for measuring parameter values from an electrical input signal comprises a signal sampling device operable to sample said input signal and to produce a corresponding output comprising a measured parameter value; a signal level detector configured to detect changes in the level of the input signal by more than a threshold amount; and a controller co-operable with the signal sampling device and the signal level detector. The controller is configured to operate the signal sampling device to sample the input signal in response to the signal level detector detecting a change in the input signal level by more than the threshold amount.

Abstract: A wheel monitoring system that includes a tracking filter apparatus for tracking a signal that has a varying main frequency. The tracking filter apparatus has an adjustable filter and a filter controller arranged to measure the amplitude of the filtered signal and to compare amplitude against a reference value. The filter controller adjusts the cut off frequency of the filter if the measured amplitude differs from the reference value by an amount that exceeds a threshold value. The filter controller adjusts the cut off frequency such that the main frequency lies within the roll off region of the filter's frequency response. The system may be used to track signals that are produced by shock sensors in a wheel mounted monitoring device.

Abstract: A method carried out in a wheel unit of a tire pressure monitoring system comprises detecting, using a controller in the wheel unit, increases and decreases in loading of a tire on a wheel associated with the wheel unit during acceleration and deceleration. Front/rear position of the wheel unit on a vehicle mounting the tire pressure monitoring system is determined, using the controller in the wheel unit, based on the loading and unloading of the tire and wheel during acceleration and deceleration. Rotation direction of the wheel in the wheel unit is determined and the controller in the wheel unit determines left/right position of the wheel unit on the vehicle based on the rotation direction of the wheel. An indication of the front/rear and left/right position of the wheel on the vehicle and an identification unique to the transmitting wheel unit are transmitted.

Abstract: A wheel position determination system and method to count wheel revolutions in a wheel unit of a tire monitoring system. An indication of the count is transmitted, optionally along with an indication of a left/right side position of the wheel on the vehicle, and an identification unique to the transmitting wheel unit, to a central controller of the tire monitoring system. In the central controller of the tire monitoring system, the count is compared with wheel speed information for the vehicle, such as from an ABS system, to determine if one wheel on each side of the vehicle is rotating at a different speed. Based at least in part upon a determination that each wheel speed is unique, a determination of wheel location may be made.

Abstract: Systems and methods for auto-location of tire pressure monitoring sensor units on a vehicle measure the angle of a wheel at two different times using a rim mounted or a tire mounted sensor and determines a difference in measured angles. The systems and methods provide for transmitting the angles and/or the difference in the measured angles along with a sensor identification to an electronic control module. Alternatively, the systems and methods provide for transmitting time differences to the electronic control module. The electronic control module correlates information transmitted from the wheel unit with antilock brake system data. A location of the wheel mounting the sensor is determined and the sensor identification is assigned.

Abstract: Auto-location systems and methods of tire pressure monitoring sensor units arranged with a wheel of a vehicle detect a predetermined time (T1) when a wheel phase angle reaches angle of interest using a rim mounted or a tire mounted sensor. The systems and methods transmit a radio frequency message associated with a wheel phase angle indication. The wheel phase angle indication triggers wheel phase and/or speed data such as ABS data at the predetermined time (T1) to be stored. A correlation algorithm is executed to identify the specific location of a wheel based on the wheel phase and/or speed data at the predetermined time (T1). TPM sensor parameters from a tire pressure monitoring sensor unit are assigned to the specific location of the wheel.

Abstract: A wheel monitoring system that includes a tracking filter apparatus for tracking a signal that has a varying main frequency. The tracking filter apparatus has an adjustable filter and a filter controller arranged to measure the amplitude of the filtered signal and to compare amplitude against a reference value. The filter controller adjusts the cut off frequency of the filter if the measured amplitude differs from the reference value by an amount that exceeds a threshold value. The filter controller adjusts the cut off frequency such that the main frequency lies within the roll off region of the filter's frequency response. The system may be used to track signals that are produced by shock sensors in a wheel mounted monitoring device.

Abstract: A TPM system wheel unit measures rotational period over a number of wheel revolutions, calculates a value of a period of the revolutions and wirelessly transmits the calculated value of the period to a tire pressure monitoring system receiver in the vehicle mounting the wheel. Alternatively, each wheel unit transmits an RF burst of a predetermined length and a received RF burst envelope modulated with a periodic modulation pattern is used to calculate the period of one wheel rotation for each wheel. A central vehicle electronic control unit monitors wheel speed signals for each wheel of the vehicle and calculates a period for the wheel speed signal for each wheel of the vehicle, bounded by a rolling window which may be of variable length. The calculated values are compared and the wheel unit and the wheel location are correlated therefrom.

Abstract: A method carried out in a wheel unit of a tire pressure monitoring system comprises detecting, using a controller in the wheel unit, increases and decreases in loading of a tire on a wheel associated with the wheel unit during acceleration and deceleration. Front/rear position of the wheel unit on a vehicle mounting the tire pressure monitoring system is determined, using the controller in the wheel unit, based on the loading and unloading of the tire and wheel during acceleration and deceleration. Rotation direction of the wheel in the wheel unit is determined and the controller in the wheel unit determines left/right position of the wheel unit on the vehicle based on the rotation direction of the wheel. An indication of the front/rear and left/right position of the wheel on the vehicle and an identification unique to the transmitting wheel unit are transmitted.

Abstract: Auto-location systems and methods of tire pressure monitoring sensor units arranged with a wheel of a vehicle detect a predetermined time (T1) when a wheel phase angle reaches angle of interest using a rim mounted or a tire mounted sensor. The systems and methods transmit a radio frequency message associated with a wheel phase angle indication. The wheel phase angle indication triggers wheel phase and/or speed data such as ABS data at the predetermined time (T1) to be stored. A correlation algorithm is executed to identify the specific location of a wheel based on the wheel phase and/or speed data at the predetermined time (T1). TPM sensor parameters from a tire pressure monitoring sensor unit are assigned to the specific location of the wheel.

Abstract: A wheel position determination system and method to count wheel revolutions in a wheel unit of a tire monitoring system. An indication of the count is transmitted, optionally along with an indication of a left/right side position of the wheel on the vehicle, and an identification unique to the transmitting wheel unit, to a central controller of the tire monitoring system. In the central controller of the tire monitoring system, the count is compared with wheel speed information for the vehicle, such as from an ABS system, to determine if one wheel on each side of the vehicle is rotating at a different speed. Based at least in part upon a determination that each wheel speed is unique, a determination of wheel location may be made.

Abstract: Systems and methods for auto-location of tire pressure monitoring sensor units on a vehicle measure the angle of a wheel at two different times using a rim mounted or a tire mounted sensor and determines a difference in measured angles. The systems and methods provide for transmitting the angles and/or the difference in the measured angles along with a sensor identification to an electronic control module. Alternatively, the systems and methods provide for transmitting time differences to the electronic control module. The electronic control module correlates information transmitted from the wheel unit with antilock brake system data. A location of the wheel mounting the sensor is determined and the sensor identification is assigned.

Abstract: A tire pressure detector employs a reduced power consumption mechanism comprising a PLL circuit including a VCO, that is operated in response to the logic states of an input data stream and a power amplifier configured to be externally located to an integrated circuit. The input data stream includes tire pressure information and is configured to be encoded to have multiple logic states. A micro-controller is employed to control the VCO, turning the VCO, and/or the amplifier, on and off for a certain period, according to the pattern of each data bit of the input data stream thus providing reduced current consumption. This tire pressure detector thus embodies an optimized circuit arrangement in terms of power efficiency.

Abstract: An apparatus for detecting motion of a wheel comprising tyre. The apparatus comprises a pressure sensor for measuring the tyre pressure and generating a signal corresponding to the measured tyre pressure, and means for detecting a component of said signal that corresponds to, or is generated by, vibrations of the tyre. Upon detection of the signal component, the apparatus determines that the wheel is in motion. The detecting means may arranged to detect an audio signal component or signal components having a frequency in the range 200 Hz to 300 Hz.