Turbocharger Sensor Thermal Decoupling

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Solution Overview

Problem

Existing rotational speed detection devices for exhaust gas turbochargers face challenges with thermal decoupling from high-temperature environments, leading to potential damage and increased costs due to the use of conventional semiconductor components.

Innovation Solution

A contactless sensor device with a magnetic field generator and sensor, where the sensor housing is thermally decoupled from the compressor housing using a non-magnetic sleeve and spacers, reducing heat conduction and using inductive coils to detect rotational speed without temperature sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the sensor housing is directly connected to the compressor housing for structural support, then mechanical stability is improved, but thermal load on the sensor increases due to heat conduction from the high-temperature environment

Engineering Contradiction:
Improvemechanical stabilityVSAvoidthermal load on sensor
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

A thermally insulating intermediate element (spacer) is introduced between the sensor housing and compressor housing. This spacer serves as a thermal barrier that blocks heat conduction paths while maintaining the mechanical connection and structural stability of the assembly.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If conventional semiconductor components are used in the sensor device, then manufacturing cost is reduced, but reliability decreases due to temperature sensitivity and potential damage from high-heat environments

Engineering Contradiction:
Improvemanufacturing costVSAvoidcomponent reliability under thermal stress
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The thermally insulating spacer acts as a protective intermediary that shields temperature-sensitive semiconductor components from high-temperature environments, enabling the use of conventional components while maintaining reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The high-temperature environment, which normally harms semiconductor components, is converted into a benefit by using the thermal gradient to improve signal detection contrast while the spacer protects the electronics from direct thermal exposure.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Measurement precision

If the sensor section is positioned close to the rotatable object for accurate detection, then measurement precision is improved, but thermal decoupling becomes more difficult

Engineering Contradiction:
Improverotational speed detection accuracyVSAvoidthermal decoupling difficulty
Core Design Contradiction:
Measurement precisionVSTemperature

Solution Approach 1:

The sensor assembly is segmented into distinct thermal zones: the sensor section remains in a cooler region while the compressor housing operates in the high-temperature zone. The spacer creates a thermal boundary that allows close positioning for accurate detection while maintaining thermal separation.

Inventive Principle:
Principle #1Segmentation

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

The solution effectively reduces thermal loads on the sensor, extends its lifespan, and lowers material costs by using common automotive plastics, while maintaining precise speed detection even under high thermal loads.

Implementation Method 1

at least one magnetic field sensor for detecting a magnetic field generated by eddy currents of the rotatable object

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 2

magnetic field generator for generating a magnetic field at the location of the rotatable object and at least one magnetic field sensor for detecting a magnetic field generated by eddy currents

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2800880B1Sensor device for the contactless detection of a rotation property of a rotatable object
Publication Date: 2020.04.29 ROBERT BOSCH GMBH
  • EP2800880B1 patent drawingFigure 1
  • EP2800880B1 patent drawingFigure 2~3
  • EP2800880B1 patent drawingFigure 4~5

AI summary

The invention relates to a sensor device (10) for the contactless detection of a rotatable object (12), in particular for the detection of the rotational speed of a compressor wheel (14) of a turbo charger (18). The sensor device (10) comprises a sensor housing (22). The sensor device (10) also comprises at least one magnetic field generator (26) for generating a magnetic field at the location of the rotatable object (12) and at least one magnetic field sensor (28) for detecting a magnetic field generated by turbulent flows of the rotatable object (12). The sensor device (10) is further provided with at least one connection element (58, 60, 62), wherein the connection element (41, 58, 60, 62) is configured to connect the sensor device (10) to a device (40) that comprises the rotatable object (12), in particular a turbo charger (18) in such a manner that the magnetic field generator (26) and the magnetic field sensor (28) are at least in part jointly arranged in a sensor segment (24) of the sensor housing (22) and the sensor housing (22), at least sections of which are spaced apart from the device (40) comprising the rotatable object (12).