Method and apparatus for detecting decrease in tire air-pressure, and program for judging decompression of tire

An apparatus for detecting decrease in tire air-pressure, which detects decrease in internal pressure of a tire on the basis of rotational information obtained from tires attached to a vehicle, the apparatus comprising:

• rotational information detecting means which detect rotational information of the respective tires;
• a rotational information storing means which stores the rotational information of the respective tires;
• a running condition detection means which detects whether the vehicle is running on a flat road or not;
• an acceleration/deceleration detection means which detects whether the vehicle is accelerating or decelerating;
• a comparison means which compares rotational information of both front wheels with rotational information of both rear wheels when it has been determined that the vehicle is running on a flat road and that the vehicle is neither accelerating nor decelerating;
• and a decompression judging means which judges simultaneous decompression of both front wheel tires or simultaneous decompression of both rear wheel tires on the basis of a relationship between a value obtained through comparison of the rotational information of both front wheels and both rear wheels and a specified threshold.

A program for judging decompression of a tire, in which for judging decrease in tire air-pressure of a tire, a computer is made to function as a rotational information storing means which stores the rotational information of the respective tires;

• a running condition detection means which detects whether the vehicle is running on a flat road or not;
• an acceleration/deceleration detection means which detects whether the vehicle is accelerating or decelerating;
• a comparison means which compares rotational information of both front wheels with rotational information of both rear wheels when it has been determined that the vehicle is running on a flat road and that the vehicle is neither accelerating nor decelerating;
• and a decompression judging means which judges simultaneous decompression of both front wheel tires or simultaneous decompression of both rear wheel tires on the basis of a relationship between a value obtained through comparison of the rotational information of both front wheels and both rear wheels and a specified threshold.