Coil-On-Plug Exciter Assembly for Cryogenic Thruster Ignition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional ignition systems for cryogenic propellants in spacecraft are bulky and unsuitable for smaller attitude control thrusters, requiring separate gasification and feed systems, and are prone to failure due to harsh environments and vibration, making them inefficient and unreliable.
Innovation Solution
A compact coil-on-plug (COP) exciter system that integrates an inductive high-voltage ignition coil within a pressure-sealed and electrically-insulating assembly, eliminating the need for separate gas supplies and sensitive electronics near the engine, using a polymer insulator and ceramic seals to provide electrical and thermal insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gas-fed miniature combustor with separate high voltage power supply and electronics is used, then reliable ignition of cryogenic propellants is achieved, but the system becomes bulky and unsuitable for smaller attitude control thrusters
Solution Approach 1:
The patent combines the high voltage power supply, electrode, and ignition coil into a single integrated coil-on-plug (COP) exciter assembly. The COP exciter directly generates high voltage at the electrode tip without requiring separate power supply electronics near the engine, thereby reducing system volume while maintaining ignition reliability through the integrated design.
2Adaptability or versatility
If separate gasification and feed systems are added to the igniter, then cryogenic propellant ignition is enabled, but the device complexity increases significantly
Solution Approach 1:
The patent extracts the gasification and feed system requirements from the igniter design by using a coil-on-plug exciter that directly ignites cryogenic propellants in liquid phase without requiring separate gasification equipment. The COP exciter generates sufficient energy to ignite the propellant directly, eliminating the need for complex gas supply systems while maintaining cryogenic propellant compatibility.
3Power
If high voltage electronics are positioned near the engine, then sufficient voltage for ignition is delivered, but the electronics are exposed to severe environments and vibration causing potential failure
Solution Approach 1:
The patent uses a coil-on-plug exciter as an intermediary device that generates high voltage through electromagnetic induction rather than using traditional high voltage electronics near the engine. The COP exciter converts low voltage input signals into high voltage output through its inductive coil mechanism, acting as a mediator that delivers required ignition power while isolating sensitive electronics from the harsh engine environment.
4Volume of moving object
If a compact COP exciter design is implemented, then mass and volume are reduced, but electrical insulation and pressure sealing become more challenging
Solution Approach 1:
The patent employs composite material structures in the COP exciter assembly, combining different materials with complementary properties to achieve both compact size and required performance. The use of composite materials allows simultaneous achievement of electrical insulation, pressure sealing, and mechanical strength in a reduced-volume design, making the compact structure manufacturable while meeting all functional requirements.
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 and efficient ignition of cryogenic propellants in vacuum environments with reduced mass, volume, and complexity, improving the reliability and packaging of small thrusters while maintaining corona-free operation.
Implementation Method 1
The COP exciter includes a COP configured to receive a first voltage and to increase the first voltage to a second voltage that is sufficient to initiate ignition
Implementation Method 2
The second voltage is conducted from the COP, through the electrode core, and to the electrode tip. The second voltage at the electrode tip generates a spark. The spark energizes a first propellant to start the engine
Data Source
AI summary
A coil-on-plug (COP) exciter includes a COP and a housing configured to be coupled to and positioned at least partially between the COP and an engine. The COP exciter also includes an electrode core positioned at least partially within the housing. The electrode core has a first end and a second end. The first end is configured to be coupled to the COP. The COP exciter also includes an electrode tip configured to be coupled to the second end of the electrode core. A voltage is conducted from the COP, through the electrode core, and to the electrode tip, which generates a spark that is configured to energize a first propellant to start the engine.