Multi-Coil Spark Ignition System for Lean Combustion
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Solution Overview
Problem
Spark ignition systems face challenges in achieving reliable combustion at lean and/or exhaust gas recirculation (EGR) cylinder charges, particularly in engines with stratified in-cylinder charges and strong charge motion, where traditional ignition methods struggle to ensure successful ignition and stable combustion.
Innovation Solution
A spark ignition system with multiple high-voltage electrodes and a low-voltage electrode, connected to a coil assembly and driver module, which uses multiple discharge channels, prolongs discharge duration, generates turbulence, and produces radical species to enhance combustion speed and reliability, employing isolated high-tension cables and feedback signals for optimized spark generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional single-coil ignition system is used, then device complexity is low, but ignition reliability deteriorates under lean and EGR conditions
Solution Approach 1:
The ignition system is segmented into multiple independent ignition coils, each capable of generating sparks at different locations within the combustion chamber. This segmentation allows the system to target specific mixture pockets more effectively, improving ignition reliability under challenging lean and EGR conditions while maintaining manageable system complexity through modular architecture.
Solution Approach 2:
The patent transitions from a single-point ignition approach to a multi-point spatial distribution of sparks within the combustion chamber. By adding the spatial dimension of multiple discharge locations, the system increases the probability of igniting the optimal mixture pocket, thereby improving reliability without proportionally increasing complexity.
2Reliability
If longer sparking duration is used, then ignition reliability improves, but energy efficiency deteriorates
Solution Approach 1:
The total sparking duration is segmented into multiple shorter discharge events occurring at different spatial locations rather than one prolonged discharge. Each coil fires for a brief period, but the cumulative effect across multiple coils achieves reliable ignition without the energy waste of extending a single spark duration.
Solution Approach 2:
The ignition system employs periodic, pulsed discharges from multiple coils rather than continuous sparking. Each coil delivers focused energy pulses at optimized intervals, improving ignition reliability through repeated attempts at different locations while maintaining energy efficiency by avoiding prolonged energy input.
3Reliability
If multiple ignition coils are added, then ignition quality improves, but device complexity increases
Solution Approach 1:
Multiple ignition coils are merged into a single integrated coil assembly with shared mounting structure and control electronics. This combining approach enables multi-point sparking for improved ignition quality while reducing overall device complexity by consolidating components that would otherwise be separate systems.
Solution Approach 2:
The coil assembly is designed with multi-functionality, serving both as a structural component and as multiple independent ignition sources. Each coil within the assembly can function independently or in combination, allowing the system to adapt to different operating conditions while maintaining a unified device structure rather than requiring separate systems.
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 system improves ignition quality by enlarging the spark kernel, providing multiple discharge channels, prolonging discharge duration, and promoting early-stage combustion turbulence, leading to more reliable and efficient combustion even under challenging conditions.
Implementation Method 1
a coil assembly having at least one primary winding and at least two secondary windings, each secondary winding having a terminal for providing a HV signal
Implementation Method 2
producing a plurality of sparks within the combustion zone based on the HV signals that are sent to each one of the at least two HV electrodes
Data Source
AI summary
An igniter for a spark ignition system includes a support body fabricated from an electrically insulating material and a metal casing disposed outwardly of and at least partially surrounding the support body. The metal casing has a structure for connecting the metal casing to ground. At least two rod-shaped first electrodes are supported one relative to another by the support body and are electrically isolated one from the other by the support body. Each first electrode has a first end that protrudes from a first end of the support body at a spark forming end of the igniter. The support body is disposed at least partly within an axial channel of a generally cylindrically-shaped second electrode. The second electrode projects past the support body at the spark forming end of the igniter and cooperates with the first ends of the at least two first electrodes to define at least two spark gaps. The second electrode is electrically isolated from the metal casing by an air gap. During use the first electrodes receive a first voltage that is higher than ground and the second electrode receives a second voltage that is lower than the first voltage. A first spark is formed within a first one of the at least two spark gaps and a second spark is formed within a second one of the at least two spark gaps.