Tire Pressure Sensor Sampling via Centrifugal Acceleration

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Solution Overview

Problem

Existing tire air pressure monitoring systems face challenges in balancing power consumption and detection accuracy, as short sampling periods increase power consumption while long periods compromise accuracy in transmitting tire air pressure information at a constant rotational position.

Innovation Solution

The system sets a sampling period based on centrifugal acceleration, detecting the gravitational acceleration component at each interval to optimize power consumption and accuracy, and adjusts the sampling period according to wheel speed, stopping detection when centrifugal acceleration exceeds a predetermined value to prevent increased power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the sampling period is set short to improve detection accuracy of rotational position, then the detection accuracy is improved, but the power consumption of the TPMS sensor increases

Engineering Contradiction:
Improvedetection accuracy of rotational positionVSAvoidpower consumption of TPMS sensor
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the sampling period variable rather than fixed. The control unit dynamically adjusts the sampling period based on detected wheel rotation speed - using shorter sampling periods at high speeds and longer sampling periods at low speeds. This dynamic adaptation resolves the contradiction by optimizing both detection accuracy and power consumption according to actual operating conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of sampling period based on wheel rotation speed. By detecting the rotation speed and adjusting the sampling period accordingly, the system achieves optimal detection accuracy when needed (short period at high speed) while conserving battery power during normal operation (long period at low speed). This parameter change strategy directly resolves the technical contradiction.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If the sampling period is set long to reduce power consumption, then the power consumption is reduced, but the detection accuracy of rotational position deteriorates

Engineering Contradiction:
Improvepower consumption of TPMS sensorVSAvoiddetection accuracy of rotational position
Core Design Contradiction:
Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The system dynamically adjusts the sampling period based on wheel rotation speed. During normal low-speed operation, a long sampling period is used to conserve battery power. When high rotation speed is detected (indicating need for precise position determination), the sampling period is shortened to ensure accurate detection. This dynamic adjustment resolves the contradiction between power consumption and detection accuracy.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sampling period parameter is changed based on detected wheel rotation speed. The control unit extends the sampling period during normal operation to reduce power consumption, and shortens it only when high-speed rotation requires precise position detection. This conditional parameter change resolves the technical contradiction effectively.

Inventive Principle:
Principle #35Parameter changes

3Duration of action of moving object

If the sampling period is extended to ensure battery life, then the battery life is extended, but the accuracy of transmitting tire air pressure information at constant rotational position is compromised

Engineering Contradiction:
Improvebattery life of TPMS sensorVSAvoidaccuracy of transmission at constant rotational position
Core Design Contradiction:
Duration of action of moving objectVSMeasurement precision

Solution Approach 1:

The patent uses dynamic sampling period adjustment to balance battery life and transmission accuracy. During normal operation with extended sampling periods, battery life is preserved. When the wheel reaches constant rotational position (detected through acceleration patterns), the system uses shorter sampling periods to accurately determine the position for data transmission. This dynamic approach ensures both battery longevity and accurate position-based transmission.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sampling period parameter is conditionally changed based on wheel rotation characteristics. Extended sampling periods are used during normal operation to conserve battery, while shorter periods are applied when constant rotational position needs to be detected for accurate data transmission. This parameter adaptation resolves the contradiction between battery life and transmission accuracy.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If the sampling cycle is shortened to improve rotational position detection, then the detection accuracy is improved, but the TPMS sensor cannot maintain long battery life

Engineering Contradiction:
Improvedetection accuracy in rotational directionVSAvoidbattery life of TPMS sensor
Core Design Contradiction:
Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The system dynamically adjusts the sampling cycle based on wheel rotation speed and position determination needs. During normal operation, a longer sampling cycle is used to extend battery life. When high-precision rotational position detection is required (shorter cycle needed), the system temporarily reduces the sampling cycle. This dynamic adjustment resolves the contradiction between detection accuracy and battery life.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sampling cycle parameter is changed based on operational requirements. The control unit uses longer sampling cycles during normal operation to preserve battery life, and switches to shorter cycles only when accurate rotational position detection is needed for wheel position determination. This conditional parameter change resolves the technical contradiction.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach effectively suppresses power consumption while enhancing detection accuracy of the gravitational acceleration component, ensuring reliable transmission of tire air pressure information and accurate wheel position determination.

Implementation Method 1

a sampling period is set based on an acceleration in a centrifugal direction (centrifugal acceleration) of the wheel, and a gravitational acceleration component of the centrifugal acceleration is detected at each prescribed sampling period or interval

Methodology Applied
Scientific EffectCentrifugal acceleration: Centrifugal Force

Data Source

PatentEP2703193B1Tire air pressure transmission device and tire air pressure monitor system
Publication Date: 2017.04.19 NISSAN MOTOR CO LTD
  • EP2703193B1 patent drawingFigure 1
  • EP2703193B1 patent drawingFigure 2
  • EP2703193B1 patent drawingFigure 3

AI summary

A tire air pressure transmission device configured so as to set a sampling period or cycle based on a centrifugal acceleration of a wheel in the centrifugal direction, and to detect the value of the gravitational acceleration component of the centrifugal acceleration each set sampling period.