Capacitor Discharge Ignition Control Circuit for Seamless Engine Shutdown
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Solution Overview
Problem
Existing capacitor discharge ignition (CDI) systems for internal combustion engines require multiple switch activations for engine shutdown and restart, and momentary switches can lead to unintended engine reactivation if not held long enough, lacking a seamless shutdown and restart mechanism.
Innovation Solution
A control circuit with a charging circuit, timing circuit, and shutdown circuit, including a charge coil, ignition capacitor, trigger coil, manual stop switch, and shut down switching device, which allows for a one-push stop switch activation that automatically resets, ensuring the ignition capacitor does not recharge until the engine stops, enabling immediate restart without further switch actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a momentary switch is used for engine shutdown, then the switch does not require resetting before restart, but the engine may resume operation if the switch is not held long enough
Solution Approach 1:
A control circuit acts as an intermediary between the momentary stop switch and the ignition system. The circuit includes a shutdown capacitor that, when charged by the momentary switch, triggers a shutdown switching device to discharge the ignition capacitor and prevent recharging, ensuring reliable engine shutdown without requiring the switch to be held or reset
Solution Approach 2:
The control circuit performs preliminary action by using the momentary switch activation to charge the shutdown capacitor in advance, which then automatically triggers the shutdown sequence through the shutdown switching device, eliminating the need for the operator to hold the switch or perform additional actions
2Reliability
If an on/off switch is used for engine shutdown, then the engine shutdown is reliable, but the switch must be reset before the engine can be restarted
Solution Approach 1:
The control circuit provides self-service functionality by automatically resetting the shutdown state after engine stoppage. When the engine stops and current flow ceases, the shutdown switching device automatically returns to its non-conductive state, allowing immediate restart without manual switch intervention
Solution Approach 2:
The control circuit serves as an intermediary that translates the momentary switch signal into a self-resetting shutdown command, managing the entire shutdown and reset sequence automatically without requiring operator intervention for switch repositioning
3Productivity
If the ignition capacitor is allowed to recharge immediately after shutdown, then the system is ready for quick restart, but the engine may accidentally restart before the operator intends
Solution Approach 1:
The control circuit performs preliminary action by pre-charging the shutdown capacitor during normal operation, so that when the momentary stop switch is activated, the shutdown sequence can immediately execute without delay, ensuring both quick restart capability and accidental restart prevention
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 provides a seamless engine shutdown and restart process, independent of switch activation duration, ensuring the engine stops immediately and can be restarted without delay, improving operational efficiency and user convenience.
Implementation Method 1
the charge coil is coupled to the ignition capacitor and charges the ignition capacitor during operation
Implementation Method 2
the trigger coil is coupled to the ignition switching device and provides the ignition switching device with a first portion of the charge that is induced in the trigger coil
Implementation Method 3
the shut down capacitor is coupled to the trigger coil and is charged with a second portion of the charge that is induced in the trigger coil
Data Source
AI summary
A control circuit for use with an ignition system of a light-duty combustion engine. In one embodiment, the control circuit includes a charging circuit, a timing circuit and a shut down circuit that includes a manual stop switch. Activation of the manual stop switch causes the control circuit to shut down the engine, and can do so even if the manual stop switch is only momentarily engaged by the operator.