Ignition Coil Self-Powered Ion Sense Circuit
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Solution Overview
Problem
Existing power circuits for ion sense circuitry, particularly those integrated with ignition coils, face challenges in efficiently supplying high voltage bias and power to ion sensors and amplification electronics without increasing complexity and cost, while also managing electromagnetic interference and ground loops.
Innovation Solution
The power supply system rectifies AC current from the ignition coil during sparking events and stores it in capacitors to generate the necessary bias voltage for ion sensing and power the amplification circuitry, eliminating the need for additional wiring, high-cost DC-DC converters, and EMI filters, and operates effectively at high engine temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a flyback DC to DC converter with step up transformer is used to generate 200-400 volt bias, then the bias voltage can be generated, but the system complexity and cost increase due to additional wiring, EMI filters, and ground loop management
Solution Approach 1:
The patent combines the bias voltage generation function with the existing ignition coil structure by integrating a high-voltage capacitor that charges during the ignition spark event. This merges the power generation function into the existing ignition system rather than adding a separate DC-DC converter, thereby reducing system complexity while maintaining bias voltage generation capability
Solution Approach 2:
The ignition system itself is used to generate the bias voltage by rectifying and storing the high-voltage spark energy in a capacitor. The system serves its own power needs by utilizing its own operational energy (the ignition spark) to charge the bias supply capacitor, eliminating the need for external power conversion equipment
2Use of energy by moving object
If additional wires are included in the system wiring harness to supply power to ion sensing circuits, then power can be supplied to the circuits, but the overall cost and complexity of the system increases
Solution Approach 1:
The ignition coil is designed to perform multiple functions: generating the ignition spark, providing bias voltage for ion sensing, and powering the amplification electronics. By making the ignition coil a multi-functional power source, the patent eliminates the need for separate power wiring harnesses, reducing overall system complexity while maintaining all necessary power supply functions
3Temperature
If high-cost ferrites are used in the DC-DC converter to operate at high engine temperatures, then the converter can operate at 90-100°C, but the cost increases
Solution Approach 1:
The patent extracts the expensive high-temperature ferrite components from the system by eliminating the DC-DC converter entirely. Instead, it uses a simple high-voltage capacitor that can be charged during the ignition event, removing the need for temperature-sensitive ferrite materials while still achieving the required operating temperature capability
Solution Approach 2:
The patent replaces expensive, temperature-sensitive ferrite-based DC-DC converter components with a simple, inexpensive high-voltage capacitor that can be rapidly charged during each ignition event. This substitution uses a much cheaper component that achieves the same functional result without the high manufacturing cost
4Temperature
If a larger single DC-DC converter is mounted off the engine to supply voltage to each coil, then the converter can operate at lower temperatures, but additional system harness wiring is required
Solution Approach 1:
The patent segments the power generation function to each individual ignition coil, with each coil having its own integrated high-voltage capacitor. This distributed architecture eliminates the need for a centralized off-engine DC-DC converter and its associated complex wiring harness, as each coil becomes self-sufficient in generating its own bias voltage
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
This solution simplifies and reduces the size of the power supply, eliminates the need for expensive ferrites and separate converters, and minimizes the risk of ground loops, providing reliable and efficient power to ion sensing and amplification circuits while maintaining performance at high temperatures.
Implementation Method 1
The power supply system rectifies AC current from the ignition coil during sparking events and stores it in capacitors to generate the necessary bias voltage for ion sensing
Implementation Method 2
combustion in an engine creates measurable ionized gas. In such an engine an ion sensor may be installed or, with proper circuitry, the ignition spark plug or ignition coil may be used to sense ion current
Data Source
AI summary
A self power circuit for ion sense circuitry is provided. The self power circuit is configured to supply the voltages required to generate and measure an ion current flow in a combustion chamber of an engine. The power circuit stores power from the current flow in the ignition coil secondary circuit during at least a portion of a sparking period for use during the ion current measurement period between sparking events. Ion current generation voltage as well as positive and negative sensor circuit power supply voltages are generated in one embodiment.