Engine Ignition Shutdown Module Using Capacitor Discharge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magneto equipped gas combustion engines face issues with excess fuel ignition during shutdown, leading to afterbang or backfire due to simultaneous grounding of the ignition signal and fuel source, and existing solutions like U.S. Pat. No. 7,520,264 are prone to self-triggering and continuous power draw, affecting engine performance.
Innovation Solution
An engine ignition shutdown module utilizing a MOSFET driver circuit that charges a capacitor during the run position, allowing controlled time delay in shutting down the ignition system relative to the fuel source, capable of interfacing with high and low voltage signals and minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ignition signal is grounded at the same time as the fuel source is shut off, then the shutdown is simple and quick, but excess fuel may not be ignited properly and burned, causing backfire in the exhaust system
Solution Approach 1:
The patent applies preliminary action by maintaining the ignition signal active for a predetermined time period after the fuel source is shut off. This time delay ensures that any excess fuel in the combustion chamber has sufficient time to ignite properly before the ignition signal is completely terminated, preventing backfire conditions while still achieving quick shutdown.
2Loss of time
If a TRIAC circuit is used to delay grounding of the magneto signal, then time delay is achieved, but the circuit is prone to self-triggering and continuously draws power from the ignition signal
Solution Approach 1:
The patent extracts the problematic continuous power draw function from the timing circuit by using a capacitor-based discharge approach. The capacitor stores energy during the run position and releases it controllably during shutdown, eliminating the need for continuous power consumption while achieving the desired time delay effect.
Solution Approach 2:
The patent replaces the TRIAC-based electrical control system with a simpler capacitor discharge mechanism. This substitution eliminates self-triggering issues and continuous power draw by using passive RC timing components that naturally provide the required delay without active power consumption.
3Loss of time
If a TRIAC circuit is used for ignition shutdown control, then time delay is provided, but the circuit cannot effectively support low voltage ignition signals
Solution Approach 1:
The patent employs parameter changes by using a capacitor discharge mechanism that naturally adapts to different voltage levels. The discharge rate and timing are determined by the RC time constant, which can accommodate both high and low voltage ignition signals without requiring voltage-specific circuit design, thereby achieving universal voltage compatibility.
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 module effectively controls the time delay between ignition system enabling and disabling, reducing power consumption and preventing backfires by minimizing the impact on the ignition signal, thus enhancing engine performance and safety.
Implementation Method 1
a MOSFET driver circuit charging a capacitor while a key switch is in a run position. The capacitor discharges through a resistor connected to a MOSFET transistor
Data Source
AI summary
An engine ignition shutdown module includes a voltage regulator circuit connected to a key switch, and a pair of isolated MOSFET driver circuits connected to the voltage regulator circuit. Each MOSFET driver circuit charges a capacitor while the key switch is in a run position and the interlock switches are closed, and each capacitor discharges through a resistor for a time delay period once the key switch is moved from the run position to an off position or at least one of the interlock switches are opened. A pair of high voltage output MOSFET transistors are switched on while the capacitors discharge and provide an output to a magneto ignition for the time delay period.