Method for monitoring the air pressure of the tires of a motor vehicle

• US 6,446,023 B1
• Filed: 04/17/2000
• Issued: 09/03/2002
• Est. Priority Date: 04/15/1999
• Status: Expired due to Term

• Current Assignee: Continental AG
• Original Assignee: Continental AG
• Inventors: Ernst, Gerhard
• Primary Examiner(s): Hilten, John S.
• Assistant Examiner(s): Cherry, Stephen J.
• Application Number:
  US09/550,492
• Time in Patent Office: 869 Days
• Field of Search: 702/138, 340/444, 340/442, 116/34.R, 731/465
• US Class Current: 702/138
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B60C 23/0423 Photo-electric, infrared or visible light means

Abstract

The invention relates to a method for monitoring the air pressure of a tire of a motor vehicle with a tire pressure control system. The invention further relates to a motor vehicle having a tire pressure control system with which the method can be carried out. The tire pressure control system includes tire pressure control devices (4a to 4d) on each of the wheels (2a to 2d), which transmit to a central unit, at regular intervals, a data transmission which contains, inter alia, the air pressure measured in the tires. The central unit generates a warning signal when the determined air pressure deviates by more than a pregiven amount from the stored air pressure. The motor vehicle contains a second tire pressure control system which operates independently of the first tire pressure control system and monitors the air pressure in the tires of the motor vehicle at least when a transmission pause, which is too long, occurs between two data transmissions of one of the tire pressure control devices (4a to 4d).

Claims

1. A method for monitoring the pressure of the tires of a motor vehicle utilizing a first tire pressure control system which includes a central unit and a plurality of tire pressure control devices on corresponding ones of the wheels of the motor vehicle for respective ones of the tires, the method comprising the steps of:

utilizing each one of said tire pressure control devices to measure the air pressure in the tire corresponding thereto at time intervals;

causing each one of said tire pressure control devices to transmit a data transmission to said central unit at time intervals with the data transmission containing at least the measured air pressure and an individual identifier characterizing said one tire pressure control device and with a transmission pause being present between two sequential data transmissions of a specific one of said tire pressure control devices;

monitoring each of the transmission pauses in said central unit which elapses after the receipt of a data transmission which is transmitted by a specific one of said tire pressure control devices;

monitoring the air pressure of the tires of said motor vehicle utilizing a second tire pressure control system at least when at least one of the transmission pauses exceeds a pregiven first limit value;

comparing the transmitted air pressure to an air pressure stored in said central unit; and

,

causing said central unit to generate an air pressure warning signal when the transmitted air pressure deviates from the stored air pressure beyond a pregiven amount.

2. The method of claim 1, wherein said warning signal is generated when at least one transmission pause exceeds a second limit value which is significantly greater than said first limit value.

3. The method of claim 1, wherein said second tire pressure control system includes a plurality of rpm sensors permanently assigned to corresponding ones of said wheels;

and, wherein said second tire pressure control system monitors the air pressure of the tires utilizing said rpm sensors.

4. The method of claim 1, comprising the further steps of:

permanently allocating an rpm sensor to each one of said wheels;

forming at least one characteristic field from the signals transmitted by the rpm sensors and the air pressures transmitted by said tire pressure control devices;

at least approximately determining the air pressure of a tire for which the specific tire pressure control device is disabled from said characteristic field when knowing the signals of the rpm sensors and the air pressures transmitted by the remaining ones of said tire pressure control devices; and

,

when the transmission pause of a specific one of said tire pressure control devices exceeds the pregiven first limit value, at least approximately determining the air pressure of the corresponding tire with the aid of said characteristic field, the rpm sensor signals and the air pressures transmitted from the remaining ones of said tire pressure control devices.

5. The method of claim 1, comprising the further steps of:

permanently allocating an rpm sensor to each one of said wheels;

forming at least one characteristic field from the signals transmitted by said rpm sensors and the air pressure transmitted by said tire pressure control devices;

determining whether the air pressure in the tires is adequate or whether the air pressure in at least one of the tires is not adequate by utilizing said characteristic field when knowing said rpm signals when several of said tire pressure control devices are disabled; and

,

when the transmission pauses of several of said tire pressure control devices exceed the pregiven first limit value, determining, with the aid of said characteristic field, whether the air pressure in the tires of the motor vehicle is adequate or whether the air pressure in at least one tire is not adequate.

6. A motor vehicle comprising:

a first tire pressure control system including a central unit and a plurality of tire pressure control devices on corresponding ones of the wheels of said motor vehicle for respective ones of the tires; and

, said first tire pressure control system functioning to monitor the air pressures of said tires as follows;

each of said tire pressure control devices measures the air pressure of the tire assigned thereto at time intervals;

each one of said tire pressure control devices transmits a data transmission to said central unit at time intervals with the data transmission containing at least the measured air pressure and an individual identifier characterizing said one tire pressure control device and with a transmission pause being present between two sequential data transmissions of a specific one of said tire pressure control devices; and

,

each transmission pause is monitored in said central unit which elapses after receipt of a data transmission which is transmitted by a specific one of said tire pressure control devices;

a second tire pressure control system for monitoring the air pressure of said tires at least when at least one transmission pause exceeds a pregiven first limit value; and

,

said control unit functioning to compare the transmitted air pressure to an air pressure stored in said central unit and functioning to generate an air pressure warning signal when the transmitted air pressure deviates from the stored air pressure beyond a pregiven amount.