US 5,513,523 A · Pneumatic tire pressure change detecting system comparing wheel speeds and weighting detection based on running conditions

Abstract

A subtractor calculates an actual wheel speed difference between rotational speeds of left and right wheels on a motor vehicle, and a steering angle converter calculates an actual steering angle from the actual wheel speed difference. The difference between the actual steering angle and an adequate steering angle which is produced based on a lateral acceleration is compared with a predetermined reference range. If the difference between the actual and adequate steering angles exceeds the predetermined reference range, then the pneumatic pressure of a tire on one of the left and right wheels is determined as being lowered. In the steering angle converter, a weight value is established according to a running condition of the motor vehicle, and the calculated actual steering angle or comparative sensitivity is varied according to the weight value. Since the comparative sensitivity is varied according to the running condition, a reduction in the pneumatic pressure of the tire can be detected even under running conditions which lead to large errors.

Claims8

Dependent claims

A system for detecting a change in the pneumatic pressure of a tire on a motor vehicle, comprising:

wheel speed difference detecting means for detecting an actual rotational wheel speed difference between rotational speeds of left and right wheels, either front or rear, on a motor vehicle;
motion condition detecting means for detecting a motion condition of the motor vehicle;
adequate wheel speed difference calculating means for calculating an adequate wheel speed difference based on an output signal from said motion condition detecting means;
comparing means for comparing said actual wheel speed difference and said adequate wheel speed difference with each other and determining the pneumatic pressure of a tire of one of said left and right wheels as being lowered if a difference between said actual wheel speed difference and said adequate wheel speed difference exceeds a predetermined value;
running condition determining means for determining a running condition of the motor vehicle;
and
comparative sensitivity modifying means for modifying a comparative sensitivity with which a reduction in the pneumatic pressure of the tire is determined, according to the running condition determined by said running condition determining means.

4 more elements

A system for detecting a change in the pneumatic pressure of a tire on a motor vehicle, comprising:

wheel speed difference detecting means for detecting an actual rotational wheel speed difference between rotational speeds of front and rear wheels on a motor vehicle;
motion condition detecting means for detecting a motion condition of the motor vehicle;
adequate wheel speed difference calculating means for calculating an adequate wheel speed difference based on an output signal from said motion condition detecting means;
comparing means for comparing said actual wheel speed difference and said adequate wheel speed difference with each other and determining the pneumatic pressure of a tire of one of said front and rear wheels as being lowered if a difference between said actual wheel speed difference and said adequate wheel speed difference exceeds a predetermined value;
running condition determining means for determining a running condition of the motor vehicle;
and
comparative sensitivity modifying means for modifying a comparative sensitivity with which a reduction in the pneumatic pressure of the tire is determined, according to the running condition determined by said running condition determining means.

4 more elements

Dependencies are inferred from the claim text.

Pneumatic tire pressure change detecting system comparing wheel speeds and weighting detection based on running conditions

Life of this patent

Pneumatic tire pressure change detecting system comparing wheel speeds and weighting detection based on running conditions

Life of this patent

Abstract

Claims8