Method and apparatus for estimating tire air pressure

An apparatus for estimating tire air pressure comprising:

• a wheel speed detection component for detecting wheel speed of each of a right-hand front wheel, a right-hand rear wheel, a left-hand front wheel and a left-hand rear wheel;
• a characteristic amount calculation component for calculating a characteristic amount of a frequency characteristic of each of the wheel speeds detected by said wheel speed detection component;
• a right-hand wheels difference-value calculation component for calculating a value of difference between right-hand wheels, which represents a degree of difference between a characteristic amount of the right-hand front wheel and a characteristic amount of the right-hand rear wheel, which characteristic amounts are calculated by said characteristic amount calculation component;
• a left-hand wheels difference-value calculation component for calculating a value of difference between left-hand wheels, which represents a degree of difference between a characteristic amount of the left-hand front wheel and a characteristic amount of the left-hand rear wheel, the characteristic amounts being calculated by said characteristic amount calculation component;
• and
• a state determination component for determining a state of air pressure of a tire based on the value of difference between right-hand wheels and the value of difference between left-hand wheels.

A method for estimating tire air pressure, comprising the steps of:

• (a) detecting wheel speed of each of a front wheel and a rear wheel;
• (b) calculating a characteristic amount of a frequency characteristic of each of the wheel speeds detected in said step (a);
• (c) calculating a value of difference which represents a degree of difference between a characteristic amount of the front wheel and a characteristic amount of the rear wheel, which characteristic amounts are calculated in said step (b);
• and
• (d) determining a state of air pressure of a tire based on the value of difference calculated in said step (c).

A method for estimating tire air pressure, comprising the steps of:

• (a) detecting wheel speed of each of a right-hand front wheel, a right-hand rear wheel, a left-hand front wheel and a left-hand rear wheel;
• (b) calculating a characteristic amount of a frequency characteristic of each of the wheel speeds detected in said step (a);
• (c) calculating a value of difference between right-hand wheels, which represents a degree of difference between a characteristic amount of the right-hand front wheel and a characteristic amount of the right-hand rear wheel, which characteristic amounts are calculated in said step (b);
• (d) calculating a value of difference between left-hand wheels, which represents a degree of difference between the characteristic amount of the left-hand front wheel and the characteristic amount of the left-hand rear wheel, which characteristic amounts are calculated in said step (b);
• and
• (e) determining a state of air pressure of a tire based on the value of difference between right-hand wheels and the value of difference between left-hand wheels.