Corona Igniter Resonant Frequency Detection During Idle Periods

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Solution Overview

Problem

Accurate detection of the resonant frequency in corona discharge ignition systems is challenging, especially due to changes during operation and the difficulty in isolating the resonant frequency from other system components, which affects the robustness of corona discharge in internal combustion engines.

Innovation Solution

A method and system that utilize an idle period with no energy supply to the corona igniter to measure its resonant frequency, allowing for accurate detection independent of other components, and adjust the drive frequency accordingly to maintain resonance during subsequent corona events, thereby optimizing energy use and discharge robustness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If energy is continuously supplied to the corona igniter to maintain corona discharge, then the robustness of corona discharge is improved, but the ability to accurately detect resonant frequency deteriorates due to interference from active discharge signals

Engineering Contradiction:
Improverobustness of corona dischargeVSAvoidaccuracy of resonant frequency detection
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system alternates between corona discharge events and idle periods in a periodic manner. During idle periods, no energy is supplied to the corona igniter, allowing the resonant frequency to be accurately detected without interference from active discharge signals. This periodic switching enables both robust corona discharge operation and precise frequency measurement to be achieved at different times in the cycle.

Inventive Principle:
Principle #19Periodic action

2Productivity

If resonant frequency detection is performed during active corona events, then continuous operation is maintained, but detection accuracy deteriorates due to changes in resonant frequency during operation

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidaccuracy of resonant frequency detection
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system performs resonant frequency detection during idle periods before the next corona discharge event begins. This preliminary detection ensures that the resonant frequency is accurately known before energy supply resumes, allowing the drive frequency to be adjusted to match the detected resonant frequency and optimize the upcoming corona discharge event.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If energy supply is interrupted to measure resonant frequency, then measurement accuracy is improved, but energy efficiency deteriorates due to interruption of corona discharge

Engineering Contradiction:
Improveaccuracy of resonant frequency detectionVSAvoidenergy interruption during measurement
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The system uses periodic idle periods between corona discharge events for frequency measurement. During these idle periods, the corona igniter is naturally not energized, so no additional energy loss occurs from interrupting the discharge. The measurement is performed during these already-existing idle times, converting what would be wasted energy periods into useful measurement opportunities.

Inventive Principle:
Principle #19Periodic 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 enables precise resonant frequency measurement and adjustment, improving the robustness and efficiency of corona discharge in internal combustion engines by utilizing energy that would otherwise be wasted, allowing the system to operate across a wider range of frequencies.

Implementation Method 1

a corona igniter with a central electrode charged to a high radio frequency voltage potential and creating a strong radio frequency electric field in a combustion chamber. The electric field causes a portion of a mixture of fuel and air in the combustion chamber to ionize and begin dielectric breakdown, facilitating combustion

Methodology Applied
Scientific EffectCorona discharge: Corona Discharge

Implementation Method 2

The electric field causes a portion of a mixture of fuel and air in the combustion chamber to ionize and begin dielectric breakdown

Methodology Applied
Scientific EffectIonization: Ionisation

Implementation Method 3

the corona discharge ignition system is preferably controlled so that energy is provided to the corona igniter at a drive frequency equal or close to the resonant frequency of the corona igniter. This provides a voltage amplification leading to robust corona discharge in the combustion chamber

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3080436B1Method for resonant frequency detection in corona ignition systems
Publication Date: 2023.11.08 FEDERAL MOGUL IGNITION LLC
  • EP3080436B1 patent drawingFigure 1
  • EP3080436B1 patent drawingFigure 2
  • EP3080436B1 patent drawingFigure 3

AI summary

A corona ignition system including a corona igniter, an energy supply, and a frequency detector is provided. The energy supply provides energy to the corona igniter during corona events which are spaced from one another by idle periods, during which no energy is provided to the corona igniter. During the idle periods, the frequency detector obtains the resonant frequency of the corona igniter from at least one of an output voltage and an output current of the energy stored in the corona igniter. The resonant frequency measured during this idle period is dependent only on the corona igniter, and not any other components of the system, and thus is very accurate. The drive frequency of future corona events can then be set based on this accurately measured resonant frequency to achieve a robust corona discharge.