What are the common types of Ignition Systems?
While aircraft manufacturers seek to continue engine development for new forms of propulsion generation, almost all modern aircraft still rely on the fuel-and-air combustion process for driving systems for flight. Ignition is a crucial part of engine processes, ensuring the efficient burning of fuel-and-air mixtures to produce hot, rapidly expanding exhaust gases that are capable of actuating turbine assemblies, cylinder assemblies, and other systems. In this blog, we will discuss the common ignition systems found across various aircraft types and models, allowing you to better understand their functionality and makeup.
For rotary engine or reciprocating engine types, ignition systems may either be a magneto-ignition or an electronic Full Authority Digital Engine Control (FADEC) system. Magneto-ignition systems, also known as inductive discharge ignition systems, may come in either single or dual configurations, differentiating from one another in regard to how many magnetos are present within a single housing. With a magnet placed on the flywheel, low-tension magneto systems produce a low-voltage that is directed to the transformer coil situated near each engine spark plug, ensuring that combustion may be carried out without risking voltage leak to ground issues. High-tension magneto systems are the most widely used type on modern aircraft, producing high-voltage for combustion.
The FADEC ignition system replaces the conventional analog electronic controls of various aircraft engines, taking advantage of computer-managed processes that govern engine settings based on various sensor readings. With solid-state digital parts, the FADEC ignition system only has one moving part which opens and closes the fuel injector. Meanwhile, sensors detect engine temperatures and pressure, fuel flow, air density, and other various values or operational conditions so that engine settings may be automatically managed. As compared to magneto engines, FADEC systems are much lighter, less bulky, easier to maintain, and may improve fuel efficiency.
Diesel engines are a bit special, forgoing the spark-based ignition system for compression ignition. As such, fuel is injected into the cylinder during high pressure and temperature conditions, causing immediate combustion without voltage. This is beneficial for reliability while also reducing the amount of shock induced on various components. Diesel engine ignition systems regularly promote longer engine service lives, though cylinders must have very high pressures and temperatures to achieve such combustion. Generally, diesel engine ignition systems are heavier than their gasoline counterparts and are only used in a narrow range of operations.
Aircraft gas turbine engines regularly feature more simplistic ignition system operations, only being used during the engine-starting cycle. As such, they often pose less issues as compared to reciprocating engine ignition systems. For the standard turbine engine, a capacitor discharge ignition system with two independent ignition units will serve as the device for carrying out combustion. Using the aircraft battery, a permanent magnet generator, or another power source, voltage is produced for igniting mixtures with a high heat intensity spark. To achieve this, a high-voltage is transferred over a wide spark gap, ensuring reliability across various atmospheric and operational conditions. Generally, the ignition system may comprise two exciter units, two transformers, two ignition leads, and two high-tension leads.
Regardless of which ignition system type is present on your aircraft, all require regular inspections and maintenance to ensure proper functionality and reliability over time. Purchasing Sphere is an online distributor of aircraft parts, and we are your sourcing solutions for resistors, spark plug components, inductor system parts, transformer equipment, and much more. Explore our various parts and manufacturer catalogs as you see fit, and our team is always ready to assist you through the purchasing process with competitive quotes and rapid lead-times 24/7x365. Get started today and see why customers steadily rely on Purchasing Sphere for all their operational requirements.
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