Ignition Coil Accelerometer Knocking Detection
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Solution Overview
Problem
Small reciprocating engines in portable power working machines, such as chain saws and brush cutters, face challenges in detecting and preventing knocking due to the high cost, weight, and size constraints of traditional knocking sensors, especially when using a flywheel magneto ignition system, which can lead to vibration, noise, and potential engine damage.
Innovation Solution
An engine knocking detection apparatus is designed with an accelerometer attached to the iron core of the ignition coil unit, connected to a control circuit board via a signal wire, and covered with a resin molded cover, allowing for precise vibration detection and suppression of knocking while minimizing cost and weight increases, and providing water and dust proofing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional knocking sensor and ECU are installed in the small engine, then knocking detection and control capability is improved, but cost, weight, and device complexity increase significantly
Solution Approach 1:
The patent extracts the knocking detection function from the traditional ECU system and integrates it directly into the ignition coil unit. The accelerometer is mounted on the ignition coil unit itself, allowing knocking detection without requiring a separate ECU or additional heavy components, thus reducing overall system weight while maintaining detection capability.
Solution Approach 2:
The patent merges the knocking detection function with the existing ignition coil unit structure. The accelerometer, signal wire, and control circuit board are integrated into the ignition coil unit, combining multiple functions (ignition control and knocking detection) into a single compact assembly, thereby reducing weight and complexity compared to separate ECU installation.
2Reliability
If a traditional knocking sensor and ECU are installed in the small engine, then knocking detection and control capability is improved, but cost increases significantly
Solution Approach 1:
The patent merges the knocking detection function with the existing ignition coil unit structure. The accelerometer, signal wire, and control circuit board are integrated into the ignition coil unit, combining multiple functions (ignition control and knocking detection) into a single compact assembly, thereby reducing weight and complexity compared to separate ECU installation.
Solution Approach 2:
The ignition coil unit is designed to perform multiple functions: traditional ignition control and knocking detection. By making the ignition coil unit multi-functional, the patent eliminates the need for separate ECU and knocking sensor components, reducing overall system cost while maintaining comprehensive functionality.
3Measurement precision
If an accelerometer is attached to the iron core of the ignition coil unit, then knocking detection precision is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by attaching the accelerometer specifically to the iron core of the ignition coil unit, which is a localized position that provides optimal vibration detection. This targeted approach allows precise knocking detection without requiring complex sensor arrays or multiple measurement points, maintaining simplicity while improving precision.
Solution Approach 2:
The patent uses a signal wire as an intermediary to connect the accelerometer to the control circuit board. This simple intermediary component allows the accelerometer data to be transmitted to the control system without requiring complex wiring harnesses or additional signal processing components, thus improving detection capability while minimizing added complexity.
4Object-affected harmful factors
If the accelerometer and control circuit board are covered with a resin molded cover, then water and dust proofing is improved, but manufacturing complexity increases
Solution Approach 1:
The patent uses a resin molded cover as a protective shell to enclose the accelerometer and control circuit board. This molded cover provides effective water and dust proofing while maintaining a compact, integrated structure. The resin material offers corrosion resistance and environmental durability, protecting the electronic components without requiring complex sealing mechanisms or multiple protective layers.
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 apparatus effectively detects and suppresses knocking with high sensitivity, reducing engine vibration and noise, and maintains cost and weight efficiency, while ensuring water and dust protection.
Implementation Method 1
an accelerometer for knocking detection attached to or mounted on the iron core or the control circuit board of the ignition coil unit
Implementation Method 2
with the use of an electromotive force generated when a magnet (permanent magnet) provided in a flywheel or the like traverses an ignition coil securely attached to a predetermined portion on a cylinder side, a high voltage is instantly applied to a spark plug to cause spark discharge
Data Source
AI summary
Provided is an engine knocking detection apparatus capable of reasonably implementing necessary measures for water and dust proofing and against breaking of a cable, and the like at low cost as well as precisely detecting and effectively suppressing or avoiding knocking while suppressing cost and weight increases as much as possible. The engine knocking detection apparatus is adapted to detect knocking in an engine that adopts a flywheel magneto ignition system with an ignition coil unit securely attached to a cylinder, the ignition coil unit including an iron core, a coil wound around the iron core, and a control circuit board attached to the coil, and has an accelerometer for knocking detection attached to the iron core of the ignition coil unit.