Sumitomo Rubber Industries Limited

Lavinder S Rehal

John C Walker

Paul Stephens

A method of determining the inflation pressure of one or more pneumatic tires on a moving vehicle having a plurality of n wheels fitted with tires by performing a set-up procedure comprising, for a range of tire inflation set-up procedure comprising, for a range of tire inflation pressures including all the vehicle tires at their scheduled inflation pressure and combinations of one or more tires at a range of pressures below their scheduled and for a range of vehicle speeds and driving conditions such as accelerating, braking, straight-ahead driving and cornering, deriving for each of the wheels a speed value Cn proportion to the wheel angular velocity, determining and saving the relationship of the set of set-up speed values to each related tire pressure, and subsequently in normal driving monitoring at intervals of time the wheel speed signals of the wheels on the vehicle, deriving an equivalent set of normal driving speed values based on these monitored wheel speed signals, obtaining the associated tire inflation pressures. The method may utilize a trainable information processing system such as a neural network to map the speed values onto the set of tire inflation pressures. The method may particularly be applied to detecting a deflated tire on a vehicle.

Method of determining the inflation pressure of a tire on a moving

A method of detecting a deflated tire on a vehicle by comparing the rolling radii of the tires by comparing angular velocity signals from wheel speed sensors at each wheel comprising the steps of calculating the factors ##EQU1## where C1, C2, C3 and C4 are the signals for the speeds of the front left-hand, front right-hand, rear left-hand and rear right-hand wheels of the vehicle, monitoring these factors and if the value of one or more factor becomes greater than 1.0005 or less than 0.9995, producing a warning signal to indicate that a tire has become partially or completely deflated.

Method of detecting a deflated tire on a vehicle

A method of detecting a deflated tire on a vehicle by comparing the rolling radii of the tires by comparing angular velocity speed signals from wheel speed sensors. One wheel speed sensor being provided at each wheel. Before the comparison of the signals is carried out, corrected wheel speed signals for each of the second, third and fourth wheels are calculated giving corrections for a set of factors comprising vehicle speed, lateral acceleration and longitudinal (fore/aft) acceleration. The corrections each comprise a constant for the factor concerned times the respective factor. The set of constants for each wheel is derived by taking the vehicle through a range of speeds, lateral and fore/aft accelerations and using multiple regression techniques and the respective factors are calculated from the set of uncorrected wheel speed signals so that comparison of the wheel speeds can be made without false signals from tire deflections caused by speed, lateral or fore/aft acceleration induced tire deflections.

A method of detecting a partially deflated pneumatic tire on a vehicle having four tires each mounted on a wheel including the steps of sensing the angular velocity of each wheel and producing a signal proportional thereto, processing the four signals in a processing unit which subtracts the sum of the signals from one pair of diagonally opposite wheels from the sum of the signals from the other pair of diagonally opposite wheels, sensing when the magnitude of the result is between 0.05% and 0.6% of the mean of the two sums to produce a signal factor and when said signal factor is present operating a warning device to indicate a tire is partially or completely deflated wherein the angular velocity of each wheel is measured simultaneously by a pulse generator providing a digital signal of more than twenty pulses per revolution of the wheel and a second signal of a single pulse per revolution of the wheel and the two angular velocity signals are both used. The method may also compare the signal for each wheel with the average of all four wheels and if the difference is greater than 0.1%, a deflation is indicated for allowing the detection of which wheel is deflated. Multi-pulse and single pulse detection may be selected according to speed and both may be used simultaneously.

A method of detecting a partially deflated pneumatic tire on a vehicle having four tires each mounted on a wheel comprising sensing the angular velocity of each wheel by providing for each wheel, a signal generator to provide a single signal or pulse for each turn of the wheel, characterized by selecting a first wheel and measuring the time for one rotation of that first wheel, after beginning the first measurement similarly measuring the times of rotation for each other wheel, storing the times for each of the wheels for at least three rotations of each wheel and averaging the times to produce an average angular velocity value for each wheel, processing the four signals in a processor unit which subtracts the sum of the signals from one pair of diagonally opposite wheels from the sum of the signals from the other pair of diagonally opposite wheels, sensing when the magnitude of the result is between 0.05% and 0.60% of the mean of the two sums and when it is operating a warning device to indicate a tire is partially or completely deflated.

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Coventry, United Kingdom

Lavinder S Rehal