EBS Pump Position Sensor NVH Reduction

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Solution Overview

Problem

The existing electronic brake systems (EBS) generate undesirable Noise, Vibration, and Harshness (NVH) during pump motor checks, which are necessary for safety standards but can disturb passengers, and existing methods to mitigate this are not fully effective.

Innovation Solution

A method that uses a pump position sensor to determine the operational status of the pump motor by comparing its initial and final positions after applying a minimal current and duration, ensuring the pump motor rotates sufficiently to confirm operation without reaching high speeds that cause noticeable NVH, thereby minimizing noise and vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pump motor is powered for sufficient time and current to generate measurable voltage, then the pump check reliability is improved, but the NVH (noise, vibration, harshness) increases making it noticeable to passengers

Engineering Contradiction:

Improvepump check reliabilityVSAvoidNVH

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the electrical measurement method (voltage generation) with a mechanical measurement method (position sensing). Instead of measuring electrical voltage generated by the motor acting as a generator, the system uses a pump position sensor to detect mechanical displacement of the pump mechanism, thereby eliminating the need for high-speed rotation that causes NVH while maintaining reliable pump functionality verification

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a pump position sensor as an intermediary device between the pump motor and the HCU. This sensor acts as a mediator that translates mechanical pump position into a detectable signal, allowing the HCU to verify pump operation without directly relying on high-speed motor rotation and voltage generation that produces noticeable NVH

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If the pump motor reaches high rotational speed to generate measurable voltage, then the voltage measurement precision is improved, but the NVH becomes noticeable to passengers

Engineering Contradiction:

Improvevoltage measurement precisionVSAvoidNVH

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent substitutes electrical voltage measurement with mechanical position measurement. The pump position sensor directly measures the mechanical displacement of the pump mechanism, providing reliable measurement data without requiring the pump motor to reach high rotational speeds that would generate measurable voltage but also cause noticeable NVH

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If the pump motor is powered for longer duration to ensure operational confirmation, then the pump check reliability is improved, but the energy consumption increases

Engineering Contradiction:

Improvepump check reliabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent performs the pump position measurement immediately upon ignition before the vehicle begins moving. The HCU activates the pump motor for a brief period to move the pump to a predetermined position and verifies this position using the sensor, thereby confirming pump operation with minimal energy expenditure before normal vehicle operation begins

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies current to the pump motor for a predetermined, limited time period that is sufficient to move the pump to a detectable position but not excessive. This partial action approach provides adequate operational confirmation while minimizing energy consumption compared to continuous or extended motor operation

Inventive Principle:

Principle #16Partial or excessive action

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 confirms the pump motor's operation with minimal NVH, ensuring passenger comfort and compliance with safety standards by using a pump position sensor to verify motor functionality with reduced power consumption and noise levels.

Implementation Method 1

The PPS utilizes a strain gauge 40 having a predetermined resistance value that is bent to a predetermined shape and positioned in a pump check position

Methodology Applied

Scientific EffectStrain gauge:

Implementation Method 2

measures the voltage generated by the motor as it continues to rotate, i.e. acts as a generator when current is no longer being applied

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2790987B1Method of using a pump position sensor for an EBS pump check

Publication Date: 2015.11.04 CONTINENTAL AUTOMOTIVE SYSTEMS INC

Figure 1~3
Figure 2~4

AI summary

A method of performing a pump check for a brake system comprises determining a first position of a pump with a pump position sensor upon ignition of a vehicle. A pump motor is powered based upon a preselected operating condition. A second position of the pump is determined with the pump position sensor. The first position of the pump and the second position of the pump are compared. The pump motor is confirmed as operational when the second position of the pump is different from the first position of the pump.