摘要:
An apparatus includes an acceleration calculation means for calculating, based on rotation speed information obtained from a rotation speed detection means, accelerations of the respective tires; an acceleration variation calculation means for calculating acceleration variations of the tires; a comparison means for comparing the acceleration variations; a presumption means for presuming a pressure decrease of a tire; an examination means for identifying, based on the tire rotation speed information, a tire having a rotation speed that is higher than the rotation speeds of the other tires or that is lower than a predetermined criterion; and a determination means for determining, when a tire identified by the presumption means is identical with a tire identified by the examination means, a pressure decrease of the tire. The the predetermined criterion defines a degree at which, when four tires have a normal internal pressure and one of the four tires is fitted with a snow chain, the tire has a lower rotation speed than the rotation speeds of the other tires. The examination means is configured to identify a tire having the slowest rotation speed. The determination means is configured to determine that a tire has a decreased air pressure when the tire identified by the presumption means is identical with the slowest tire identified by the examination means and when the slowest tire is positioned at a driven wheel.
摘要:
The apparatus for detecting a decreased air pressure of a tire includes an acceleration calculation means for calculating, based on rotation velocity information of tires of respective wheels of a vehicle; an acceleration variation calculation means for calculating acceleration variations of the respective tires; a comparison means for comparing the acceleration variations of the respective tires; an estimation means for estimating, when a comparison result of the comparison means shows that an acceleration variation of a certain tire is greater than acceleration variations of the other tires, a decrease in air pressure of the certain tire; a test means for determining a tire having a rotation velocity that is faster than the rotation velocities of the other tires or that is further slower than a predetermined reference; and a judgment means for judging, when a certain tire identified by the estimation means is identical with the tire identified by the test means, a decrease in air pressure of the certain tire.
摘要:
An apparatus for detecting a decrease in air pressure of a tire attached to a vehicle. The apparatus includes a rotation speed detection means for periodically detecting rotation speeds of tires of respective wheels of the vehicle; a rotation wheel speed ratio calculation means for calculating, based on rotation speed information obtained by the rotation speed detection means, a rotation wheel speed ratio between front wheels and rear wheels of the vehicle with regard to a plurality of predetermined speed regions; a wheel torque calculation means for calculating a wheel torque of the vehicle; an initialization means for obtaining, with regard to the respective speed regions, a relation at a normal internal pressure between the wheel torque and the rotation wheel speed ratio between the front wheels and the rear wheels; a storage means for storing the relation obtained by the initialization means; a comparison means for comparing, with regard to the respective speed regions, the rotation wheel speed ratio obtained by the rotation wheel speed ratio calculation means with the rotation wheel speed ratio at a normal internal pressure obtained from the wheel torque obtained by the wheel torque calculation means and the relation stored by the storage means; and a determination means for correcting the comparison result by the comparison means by a front-to-rear direction acceleration and for determining, based on the resultant corrected value, whether there is a tire having a decreased air pressure or not.
摘要:
An apparatus includes an acceleration calculation means for calculating, based on rotation speed information obtained from a rotation speed detection means, accelerations of the respective tires; an acceleration variation calculation means for calculating acceleration variations of the tires; a comparison means for comparing the acceleration variations; a presumption means for presuming a pressure decrease of a tire; an examination means for identifying, based on the tire rotation speed information, a tire having a rotation speed that is higher than the rotation speeds of the other tires or that is lower than a predetermined criterion; and a determination means for determining, when a tire identified by the presumption means is identical with a tire identified by the examination means, a pressure decrease of the tire. The the predetermined criterion defines a degree at which, when four tires have a normal internal pressure and one of the four tires is fitted with a snow chain, the tire has a lower rotation speed than the rotation speeds of the other tires. The examination means is configured to identify a tire having the slowest rotation speed. The determination means is configured to determine that a tire has a decreased air pressure when the tire identified by the presumption means is identical with the slowest tire identified by the examination means and when the slowest tire is positioned at a driven wheel.
摘要:
An apparatus for alarming decrease in tyre air-pressure in which decrease in internal pressure of tyres is alarmed based on rotational information obtained from tyres attached to a four-wheeled vehicle. The apparatus comprises a rotational information detecting means for detecting rotational information of each tyre, a memory means for storing the rotational information of each tyre, a calculating means for calculating reciprocals of turning radii based on rotational information of tyres attached to a driving shaft and judged values from the rotational information of each tyre, and a determining means for determining decrease in internal pressure from a relationship between the reciprocals of the turning radii and judged values. Determination of decompression can be reliable performed in the proximity of a region at which the lateral axis is O, since the judged values (DEL values) obtained while the differentiation is restricted are focused at points at which the lateral axis is O, that is, on the vertical axis.
摘要:
A method for detecting decrease of tyre air pressure comprising detecting each angular velocity of rotation (1,2,3,4) of four tyres (W1,W2,W3,W4), judging as to whether the tyre air pressure is decreased or not based on the detected angular velocity of rotation, and issuing alarm. The method includes a judgement step for low velocity in which, when the angular velocity of rotation is detected, judgement is made as to whether the tyre air pressure is decreased or not, and a judgement step for high velocity in which, when the angular velocity of rotation is detected, judgement is made as to whether the tyre air pressure is decreased or not only when the vehicle velocity is higher than a predetermined threshold value and the vehicle is in driven condition.