Heating System Sensor Aging Detection via Ionization Current

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Solution Overview

Problem

Existing methods for detecting the aging condition of heating system sensors, such as ionization probes, require special test phases that result in increased energy consumption and pollutant emissions, as they are not available for normal operation and must be tested in different power ranges.

Innovation Solution

A method that monitors the time profile of combustion parameters, specifically the ionization current, during normal heating operation to determine the aging state of sensors, allowing for continuous system availability and reduced emissions by restricting or shutting down the system if necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If special test operating phases are used to detect sensor aging state, then the aging state can be determined, but the heating system is unavailable for normal operation and energy consumption increases

Engineering Contradiction:
Improveaging state detectionVSAvoidsystem availability
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent combines the aging detection function with the normal ignition operation. The ionization current is monitored during the regular ignition sequence without requiring separate test phases, thus merging two functions into one operational cycle.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The aging detection is performed during the ignition phase before normal heating operation begins. This preliminary action allows the system to assess sensor condition upfront, enabling immediate availability for heating without requiring additional test time.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the gas burner is operated at different power levels during test phases, then sensor aging can be detected, but pollutant emissions increase

Engineering Contradiction:
Improvesensor aging detectionVSAvoidpollutant emissions
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent utilizes natural parameter variations that occur during the ignition process itself. The ionization current changes as the flame develops and stabilizes, providing sufficient variation to detect sensor aging without requiring deliberate power level changes or additional combustion cycles.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If ionization probe is used to detect combustion parameter, then the aging state can be monitored, but the oxide layer reduces the detected ionization current

Engineering Contradiction:
Improvecombustion parameter detectionVSAvoidionization current signal
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent employs a dynamic evaluation method that tracks the temporal development of the ionization current during ignition. By analyzing how the current changes over time rather than relying on a single static value, the system can distinguish between current reductions caused by oxide layers and those caused by actual combustion conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from the ionization current temporal profile to detect aging state. The control unit continuously monitors the ionization current during ignition and compares the observed temporal development against expected patterns, providing feedback that indicates sensor aging without requiring separate calibration procedures.

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 continuous operation of heating systems with minimal emissions and increased operational reliability by determining the aging state immediately upon startup and adjusting the system's operation accordingly.

Implementation Method 1

By way of example, consideration can be given to the temporal profile of a combustion parameter, in particular an ionization current, during ignition operation

Methodology Applied
Scientific EffectIonization: Ionisation

Data Source

PatentEP3290797B1Method for detecting a state of ageing of a heating system as well as a control unit and a heating system
Publication Date: 2021.10.06 ROBERT BOSCH GMBH
  • EP3290797B1 patent drawingFigure 1
  • EP3290797B1 patent drawingFigure 2~3

AI summary

The invention relates to a method for detecting the aging state of a heating system (46). It is proposed that a temporal profile of a combustion parameter (66), in particular an ionization current (56), is taken into account during ignition operation. The invention also relates to a method for determining an inspection time of the heating system (46), a method for controlling an ignition operation of the heating system (46), a control unit (18) configured to carry out a method according to the invention, and a heating system (46) with the control unit (18) according to the invention.