Single Coil Ignition System for Internal Combustion Engine
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Solution Overview
Problem
Inductive ignition systems for internal combustion engines are costly due to the need for separate primary and secondary windings for each cylinder, and electronic control units used in other systems are expensive, making them impractical for small engines.
Innovation Solution
An ignition system utilizing a single primary coil to induce current in a secondary coil, which is directed to either of two spark plugs through diodes or flow restrictors, allowing for efficient current distribution without the need for multiple windings or expensive control units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate primary and secondary windings are used for each cylinder, then ignition reliability is improved, but system cost increases
Solution Approach 1:
A single ignition coil assembly is designed to serve multiple cylinders through a multi-layer winding structure. The primary winding has multiple tap points that can be connected to different cylinders, allowing one coil to function for multiple cylinders simultaneously, thereby reducing the number of coils needed while maintaining ignition reliability
Solution Approach 2:
The primary winding is divided into multiple segments with separate tap points, allowing independent control and connection to different cylinders. This segmentation enables the single coil to serve multiple functions and reduces overall system complexity
2Measurement precision
If electronic control units are used to control ignition timing, then ignition timing precision is improved, but system cost increases
Solution Approach 1:
The ignition system uses the engine's own rotational energy to generate the electrical power needed for control. A flywheel with permanent magnets induces current in a generator coil, creating a self-powered system that eliminates the need for external batteries or complex electronic control units while maintaining precise ignition timing control
3Device complexity
If a single primary coil is used to power multiple spark plugs, then system cost is reduced, but current distribution control becomes difficult
Solution Approach 1:
The primary winding is segmented with multiple tap points along its length. These tap points allow selective connection to different cylinders, enabling independent current control for each spark plug while using a single coil, thus simplifying the system while maintaining operational control
Solution Approach 2:
A controller acts as an intermediary between the single primary coil and multiple spark plugs. It manages the current distribution by selectively connecting different tap points of the primary winding to appropriate cylinders, simplifying the overall system architecture
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 solution reduces the cost and complexity of the ignition system by using a single primary coil to power multiple spark plugs, while allowing for precise control of ignition timing through a controller, effectively addressing the cost issues of existing systems.
Implementation Method 1
a single primary coil to provide current to a single secondary coil... As the magnets pass the primary coil, a first current flowing in a first direction is induced in the primary coil... The first and second currents induced in the secondary coil flow in opposite directions
Implementation Method 2
The magnets spaced around the outer circumference of the flywheel have either a first polarity or a second polarity. As the flywheel rotates, the magnets pass a primary coil that is positioned adjacent to the flywheel. As the magnets pass the primary coil, a first current flowing in a first direction is induced in the primary coil
Data Source
AI summary
An ignition system for an internal combustion engine that utilizes a single primary coil and a single secondary coil to drive a pair of spark plugs. Current flowing in both a first direction and a second direction passes through the primary coil. The current flowing through the primary coil induces corresponding current in the secondary coil, which flows from the secondary coil to one of two spark plugs. Each spark plug is coupled to the secondary coil such that each of the two spark plugs receives current flowing only in a single direction. The current flowing through the ignition system can be from either a power source or created by the rotation of a flywheel having a series of magnet clusters.