Ignition Device Microcomputer Control for Stable Timing
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Solution Overview
Problem
General purpose engines with recoil starters lack reliable ignition timing control, leading to excessive output, spark plug wear, and heat issues in the secondary coil, especially without a battery-powered system, which complicates engine operation and emission control.
Innovation Solution
An internal combustion engine ignition device with a permanent magnet attached to a rotor, an induced power generation coil, a switching element, and a microcomputer that uses a common ground for control, allowing precise ignition timing adjustment based on primary current detection and rotational speed, stabilizing output and preventing excessive energy application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the ignition timing is not controlled, then the structure is simplified, but the output becomes excessively large causing spark plug wear and heat generation
Solution Approach 1:
The system uses itself to provide the necessary functions. The ignition coil's primary winding generates induced power that is fed back to control the microcomputer and rotation detection circuit, eliminating the need for external battery power and simplifying the overall structure while maintaining control capability.
Solution Approach 2:
The primary coil serves multiple functions: generating ignition voltage and simultaneously providing power for the control system. This multi-functionality reduces the number of separate components needed, simplifying the device structure while maintaining reliable control.
2Manufacturing precision
If a microcomputer is used for ignition timing control, then the ignition timing can be precisely controlled, but the device complexity increases
Solution Approach 1:
The power supply system and control system are merged into one integrated structure. The microcomputer and rotation detection circuit share the same power source (induced power from the primary coil) and are combined in a single control unit, reducing overall device complexity while maintaining precise control capability.
3Device complexity
If the induced power is used for both microcomputer operation and spark generation, then no external battery is needed, but the power distribution must be precisely controlled
Solution Approach 1:
The system implements feedback control where the microcomputer monitors the ignition timing and primary current, then adjusts the switching element's operation accordingly. This feedback mechanism ensures proper power distribution between the microcomputer and spark generation while maintaining precise control.
Solution Approach 2:
The system dynamically adjusts the switching element's on/off timing based on real-time conditions detected by the rotation detection circuit and primary current measurement. This dynamic control allows the system to optimize power distribution under varying operating conditions.
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 enables stable ignition timing control and reduced wear, ensuring efficient engine operation and emission compliance without the need for an external battery, by utilizing the induced power for both microcomputer operation and spark generation, thus preventing excessive output and heat issues.
Implementation Method 1
a magnetic path is formed using the permanent magnet (4)... an induced power generation coil (L) wound over a core (12)... voltage induced in the primary coil
Implementation Method 2
The microcomputer drives the switching element to rapidly change the current flowing through the induced power generation coil and generate a high voltage in the secondary coil
Implementation Method 3
carries out ignition by generating spark discharge in a spark plug connected to the secondary coil
Data Source
AI summary
The internal combustion engine ignition device has a core, a coil part that is wound over the core, and a secondary coil that is wound on the outer peripheral side of the coil part. A switching element switches an induced current, which is generated via the rotation of a permanent magnet, of a primary coil on and off. A resistor and a microcomputer are connected to the switching element, and a rotation detection circuit is connected to the microcomputer. The microcomputer drives the switching element so as to rapidly change the current flowing through the primary coil and generate a high voltage in the secondary coil, and generate a spark discharge in a spark plug connected to the secondary coil. In the coil part, one coil is divided by an intermediate tap, forming the primary coil and a charging coil.