Capacitor-Discharge Ignition Engine Stop Circuit
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Solution Overview
Problem
Existing capacitor-discharge ignition (CDI) systems for internal combustion engines cannot reliably stop the engine when the engine stop switch is manipulated due to potential wire breakage in the switch circuit, preventing immediate engine shutdown.
Innovation Solution
A CDI system incorporating a microprocessor that controls a switching element to discharge stored energy from a capacitor to an ignition coil, with an engine stop switch connected to the microprocessor to ensure engine shutdown upon operator command, and an independent ignition stop circuit to maintain functionality even with wire breakage or microprocessor issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional engine stop switch is used to ground or short-circuit the power generation coil or primary ignition coil, then the engine can be stopped, but wire breakage in the switch circuit makes it impossible to stop the engine
Solution Approach 1:
The patent introduces a microprocessor as an intermediary between the engine stop switch and the ignition system. The microprocessor receives signals from the engine stop switch and controls the switching element accordingly. This intermediary approach allows the system to detect switch activation and respond reliably even if wire breakage occurs in the traditional direct grounding circuit, thereby improving engine stop reliability without significantly increasing overall system complexity.
Solution Approach 2:
The patent replaces the traditional mechanical direct-grounding switch circuit with an electronically controlled system using a microprocessor and switching element. Instead of relying on mechanical wire grounding to stop the engine, the system uses electronic signal processing and controlled disconnection through the microprocessor, which can detect and respond to switch activation more reliably despite potential wire issues.
2Speed
If the engine stop switch directly grounds the ignition coil, then the engine stops immediately, but the system becomes vulnerable to wire breakage
Solution Approach 1:
The microprocessor serves as an intermediary that receives the engine stop switch signal and processes it before activating the switching element. This intermediate processing step ensures that the system responds reliably to stop commands even when wire breakage occurs in the traditional direct circuit, maintaining both fast response speed and high reliability by detecting and acting on the stop signal through the microprocessor's control logic.
Solution Approach 2:
The microprocessor continuously monitors the engine stop switch signal and provides feedback control to the switching element. When the engine stop switch is activated, the microprocessor detects this signal and immediately activates the switching element to disconnect the ignition coil, ensuring reliable engine shutdown. The feedback mechanism ensures that the system responds correctly even if there are issues with the direct wiring path.
3Reliability
If a microprocessor-controlled switching element is used, then the engine can be reliably stopped, but the device complexity increases
Solution Approach 1:
The microprocessor is designed to perform multiple functions: it controls the ignition timing by activating the switching element at predetermined crank angular positions, processes engine stop commands from the engine stop switch, and monitors system conditions. By making the microprocessor multi-functional, the patent improves engine stop reliability through sophisticated control while minimizing the increase in overall device complexity, as the same microprocessor handles both ignition control and engine shutdown without requiring separate dedicated circuits.
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
Enables reliable engine shutdown at any time, regardless of operator intervention or circuit failures, ensuring safety and operational control by disconnecting ignition through the microprocessor and independent ignition stop circuit.
Implementation Method 1
a power generation coil which is fixed on the engine body inside a rotating flywheel to generate electric power when crossing the fluxes of magnets fastened on the inner wall of the rotating flywheel
Implementation Method 2
a capacitor which stores the electric power produced by the power generation coil
Implementation Method 3
the charge stored in the capacitor is discharged to the primary winding of an ignition coil through the switching element so as to produce high voltage for ignition in the secondary winding
Implementation Method 4
produce ignition in the spark plug to ignite air-fuel mixture in a combustion chamber of the engine
Data Source
AI summary
In a capacitor-discharge ignition system for an internal combustion engine having a power generation coil, a capacitor connected to the power generation coil, an ignition coil having a primary winding connected to the capacitor through a thyristor and a secondary winding connected to a spark plug, and a microprocessor which turns on the thyristor at a predetermined crank angular position to produce ignition in the spark plug, an engine stop switch is installed to input an engine-stop command signal to the microprocessor when being turned off by the operator. With this, it becomes possible to surely stop the engine at any time if desired.