Hydrogen Engine Ignition Circuit for Residual Energy Dissipation

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Solution Overview

Problem

Existing ignition devices for internal combustion engines suffer from residual energy in the secondary circuit leading to undesired ignition, potentially damaging components like the intake tract and throttle valve.

Innovation Solution

A parallel path is introduced electrically parallel to the diode in the secondary circuit, equipped with an ohmic load resistor or an electrical switch, to dissipate residual energy, ensuring it bypasses the diode and is conducted to ground, thereby preventing unwanted ignition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a diode is used in the secondary circuit for spark suppression, then switch-on sparks are prevented, but residual energy remains in the circuit causing undesired ignition

Engineering Contradiction:
Improveswitch-on sparksVSAvoidresidual energy causing undesired ignition
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The secondary circuit is segmented into two parallel paths: one with the diode for switch-on spark suppression, and another with the load resistor for residual energy dissipation. This segmentation allows each component to address a specific harmful effect without interfering with the other's function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The load resistor acts as an intermediary element that provides a controlled discharge path for residual energy. It mediates between the energy stored in the secondary circuit and the potential harmful effects by gradually dissipating the energy through resistive heating, preventing both switch-on sparks and undesired ignition.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the diode's spark suppression function is strengthened, then switch-on sparks are better prevented, but the diode conducts more residual energy causing undesired ignition

Engineering Contradiction:
Improveswitch-on sparksVSAvoidprevention of undesired ignition
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The circuit is divided into two functional segments: the diode segment handles switch-on spark suppression, while the load resistor segment handles residual energy dissipation. This segmentation allows the diode to be optimized for spark suppression without being overloaded with residual energy, which would otherwise cause undesired ignition.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The harmful function of residual energy conduction through the diode is extracted and transferred to the load resistor. By taking out this function from the diode's responsibility, the diode can focus solely on spark suppression, while the load resistor independently handles residual energy dissipation.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If a parallel path with load resistor is added to dissipate residual energy, then undesired ignition is prevented, but device complexity increases

Engineering Contradiction:
Improveprevention of undesired ignitionVSAvoidcircuit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The load resistor is merged with the existing diode structure in a parallel configuration, sharing common connection points in the secondary circuit. This merging approach allows the additional functionality to be integrated into the existing circuit layout without requiring completely separate components or complex wiring arrangements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The parallel path with load resistor serves multiple functions: it dissipates residual energy to prevent undesired ignition, provides an alternative current path that protects the diode, and maintains circuit operation during both charging and discharging phases. This multi-functionality justifies the added component by delivering multiple benefits from a single structural addition.

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

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 extinguishes residual energy, preventing undesired ignition and protecting engine components while maintaining the diode's spark suppression function.

Implementation Method 1

a transformer (2) with a primary circuit (2.1) and a secondary circuit (2.2), wherein the primary circuit (2.1) has a primary coil (3), wherein the secondary circuit (2.2) comprises a secondary coil (4) inductively coupled to the primary coil (3)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a diode (5) for spark suppression

Methodology Applied
Scientific EffectDiode rectification: Diode

Implementation Method 3

an ohmic load resistor (11) arranged in the parallel path (10), by means of which residual energy, in particular a residual voltage that remains in the secondary circuit (2.2) after a discharge of the ignition device (1), can be extinguished

Methodology Applied
Scientific EffectOhmic heating: Joule Heating

Data Source

PatentEP4264037B1Ignition device for an internal combustion engine
Publication Date: 2025.08.06 ROBERT BOSCH GMBH
  • EP4264037B1 patent drawingFigure 1
  • EP4264037B1 patent drawingFigure 2
  • EP4264037B1 patent drawingFigure 3

AI summary

The invention relates to an ignition device (1) for an internal combustion engine, more particularly for a hydrogen fuelled internal combustion engine, comprising a primary circuit (2.1) and a secondary circuit (2.2), wherein - the primary circuit (2.1) has a primary coil (3), wherein - the secondary circuit (2.2) has a secondary coil (4) inductively coupled to the primary coil (3), a diode (5) for suppressing a start-up spark and a high-voltage connector (6) for connection to a spark plug (7), characterised in that a parallel path (10) is formed electrically in parallel to the diode (5) of the secondary circuit (2.2), in which parallel path there is arranged an ohmic load resistor (11) or an electric switch (20) and by means of which parallel path residual energy, in particular residual voltage, which remains in the secondary circuit (2.2) following discharge of the ignition device (1), can be extinguished, in particular by feeding the residual energy in the secondary circuit (2.2) past the diode (5), bypassing the diode (5).