Broadband Lambda Probe Control Unit for State Diagnostics

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Solution Overview

Problem

Existing broadband lambda sensors lack the capability to provide comprehensive information about their operating state, limiting their functionality in ensuring accurate fuel mixture control and diagnostics in vehicles.

Innovation Solution

An evaluation and control unit that determines not only the pump current but also additional operating parameters of the broadband lambda sensor, providing this information through a digital interface for rapid processing and response, allowing for enhanced diagnostics and control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If only pump current is measured by the lambda sensor, then the device complexity is low, but the diagnostic capability and operating state information are insufficient

Engineering Contradiction:
Improveoperating state informationVSAvoidevaluation and control unit
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The evaluation and control unit is designed to perform multiple functions: it determines pump current, calculates internal resistance, detects polarization states, and provides diagnostic information. This multi-functional approach allows comprehensive sensor monitoring without requiring separate dedicated devices for each measurement type.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The evaluation and control unit acts as an intermediary between the lambda sensor and the vehicle's control systems. It processes raw sensor signals, adds diagnostic information, and outputs enhanced data through a digital interface, thereby enriching the information available without modifying the sensor itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If comprehensive sensor monitoring is implemented, then the measurement precision and diagnostic accuracy improve, but the processing time and system response time increase

Engineering Contradiction:
Improveoperating state detectionVSAvoiddata processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The evaluation and control unit continuously calculates internal resistance and monitors polarization states in the background during normal operation. This preliminary processing ensures that diagnostic information is ready immediately when needed, rather than requiring additional processing time during critical decision-making moments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system performs multiple measurements and calculations continuously without interruption. The pump current determination, internal resistance calculation, and polarization detection all occur in an ongoing manner, ensuring that comprehensive data is always available without periodic delays.

Inventive Principle:
Principle #20Continuity of useful action

3Adaptability or versatility

If additional operating parameters are determined and provided through digital interface, then the adaptability and control capability improve, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvecontrol and diagnostics functionalityVSAvoidevaluation and control unit
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The system implements feedback loops where the evaluation and control unit continuously monitors sensor performance parameters such as internal resistance and polarization state. This feedback enables automatic adjustment and optimization of sensor operation, enhancing adaptability while using standardized electronic components that maintain ease of manufacture.

Inventive Principle:
Principle #23Feedback

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

Enables advanced diagnostics and control of lambda sensors, ensuring accurate fuel mixture adjustment and early detection of sensor issues, thereby improving vehicle emissions management.

Implementation Method 1

A detection voltage corresponding to the oxygen concentration, supplied by a Nernst measuring cell

Methodology Applied
Scientific EffectNernst effect: Nernst Effect

Implementation Method 2

An electrical pumping voltage generating a pumping current is applied between an inner pumping electrode and an outer pumping electrode of a pumping cell. This voltage is used to establish a constant oxygen partial pressure in a first measuring gas chamber by pumping oxygen in or out.

Methodology Applied
Scientific EffectElectrical pumping: Electro-Osmosis

Implementation Method 3

The sensor has an outer electrode connected to a solid electrolyte and exposed to the solid gas, and an electrode connected to the solid electrolyte, between which oxygen can be pumped by means of a pump current flowing through the solid electrolyte.

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentEP2277035B2Evaluation and control unit for a broadband lambda probe
Publication Date: 2025.09.17 ROBERT BOSCH GMBH
  • EP2277035B2 patent drawingFigure 1
  • EP2277035B2 patent drawingFigure 2
  • EP2277035B2 patent drawingFigure 3a~3b

AI summary

The invention relates to an evaluation and control unit (1) for a broadband lambda probe (2), comprising a signal conditioning unit (5), an analog-digital-converter (6), a pump current regulator (7), a digital interface (8), a control device (10), a pump current source (11), an internal pump electrode connection (IPE), an external pump electrode connection (APE) and a reference electrode connection (RE). Said signal conditioning unit (5) is provided to determine an actual value for the pump current regulator (7) and to determine additional information relating to the operational state of the broadband lambda probe. The additional information relating to the operational state of the broadband lambda probe can be outputted via the digital interface (8).