Ignition Control for Low-Speed Engine Starting
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Solution Overview
Problem
Existing ignition systems for combustion engines face challenges in starting the engine at low rotational speeds due to low amplitude alternating voltage half-waves, leading to inefficient charging of the ignition capacitor and potential kick-back issues, which require increased manufacturing costs and larger installation space to address.
Innovation Solution
A control methodology for the ignition system that uses microelectronic and programmable control means to detect rotational position at low speeds, advances the ignition point closer to TDC, and maintains a fully charged capacitor during stoppages, allowing ignition during the first pass through TDC at low speeds, with a high-resistance capacitor circuit to prevent discharge during stoppages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the engine rotates at low speed, then the alternating voltage half-waves have low amplitude, but the ignition capacitor cannot be charged sufficiently
Solution Approach 1:
The ignition capacitor is charged in advance during periods when the engine is stopped or running at higher speeds. The control unit monitors the charge state and ensures the capacitor is fully charged before a low-speed start attempt, enabling reliable ignition even when the engine subsequently runs at low rotational speeds where the induced voltage would otherwise be insufficient.
Solution Approach 2:
The system uses a magnetic generator with permanent magnets that replicate the magnetic field pattern during each rotation. This consistent magnetic field copying ensures that the same voltage waveform is generated each rotation, allowing the control unit to predict and prepare for low-voltage conditions by pre-charging the capacitor during previous high-speed rotations or idle periods.
2Ease of operation
If the ignition capacitor is discharged during stoppages, then the system is reset, but the engine cannot be restarted immediately
Solution Approach 1:
The system dynamically adjusts the discharge behavior of the ignition capacitor based on operational state. During normal stoppages, the capacitor maintains its charge to enable immediate restart. The control unit only discharges the capacitor when a stop switch is activated or when a kick-back condition is detected, creating a dynamic response that balances restart capability with system protection.
Solution Approach 2:
The control unit continuously monitors the engine state, capacitor charge level, and operational conditions. Based on this feedback, it intelligently decides whether to maintain charge for immediate restart or to discharge for protection. The system provides feedback signals to indicate charge status and restart readiness, enabling informed operational decisions.
3Productivity
If the ignition point is advanced too much at low speeds, then ignition occurs before TDC, but kick-back problems occur
Solution Approach 1:
The control unit dynamically adjusts the ignition timing parameter based on the detected rotational speed. At low speeds, the ignition point is set closer to TDC (reducing advance angle) to prevent kick-back, while at higher speeds, greater advance is permitted. The system also adjusts the capacitor charge voltage based on speed, providing higher voltage at low speeds to compensate for the reduced timing advance, thereby maintaining ignition effectiveness without causing harmful knock-back.
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 easy starting and restarting of the engine with low power requirements, achieving effective ignition at low rotational speeds and providing a high-voltage spark even after a break, reducing the need for extensive system design and installation space.
Implementation Method 1
the magnetic field of the magnetic generator flows intermittently through the coils and for each revolution a sequence of magnetic flux changes are generated. As a result, corresponding alternating voltage half-waves are induced in the coils.
Implementation Method 2
an energy storage element, for example an ignition capacitor, is charged with the alternating voltage half-waves and is discharged through actuation of an ignition switch via the primary coil windings
Implementation Method 3
discharged through actuation of an ignition switch via the primary coil windings of a pulse transformer for initiating an ignition spark
Data Source
AI summary
An electrical ignition method for a combustion engine employing the use of an arrangement of several coils and a magnet wheel or magnet generator which rotates synchronously with the combustion engine, wherein the magnetic field of the magnet generator intermittently flows through the coils and therein generates a sequence of magnetic flux changes per revolution, whereby a sequence of corresponding alternating voltage half-waves is induced in the coils, which are used for charging an energy storage element. Through the use of a stop and/or switch-off system for the combustion engine, the disclosed method prevents a discharge of the energy storage element during the stopping and coast down procedure of the combustion engine and/or to actuate its charging, so that a charged energy storage element is available for the next start of the combustion engine.