electronics MIDTERM

• The function of the ignition system is to provide an electrical spark to ignite the fuel/air mixture in the cylinders.
• The typical firing order for cylinders in a horizontally opposed aircraft engine with dual magneto ignition is 1-4-2-3.
• battery is the component of the ignition system genertaes the high-voltages spark
• in a typical small aircraft two magnetos are used in the ignition system
• The purpose of the ignition timing in an aircraft engine to optimize engine performance.
• spark plug is the component of the aircraft ignition system generates a high-voltage spark by utilizing the collapse of a magnetic field accross a second set of windings
• ignition coil is the component in the aircraft ignition system completes the primary circuit when the ungrounded breaker point contacts the grounded breaker point
• when the primary circuit is closed in an aircraft ignition system. induction of magnetic flux occurs as a result of the current flow through the primary coil
• number of turns of wire in the secondary winding is the factor primarily determines the strength of the voltage induces in the secondary windings of an aircraft ignition system
• there are one electrodes per cylinder THE DISTRIBUTOR BLOCK TYPICLLY HAVE IN AN AIRCRAFT IGNITION SYSTEM FOR A FOUR-STROKE CYCLE ENGINE
• electrodes typically arranged on the distributor block in an aircraft ignition system in circumferentially around the distributor block
• The ignition lead directs the electrical energy from the magneto to the spark plug
• The ignition harness contains an insulated wire for each cylinder that the magneto serves in the engine
• If the magneto and ignition leads were not shielded, they would act as antennas and pick up random frequencies from the ignition system
• The consequence of not shielding the magneto and ignition leads in an aircraft ignition system is an increased risk of electromagnetic interference
• The lead shielding is a medal mesh braid that surrounds the entire length of the lead. The lead shielding prevents the radiation of the energy into the surrounding area.
• When shielding is placed around the ignition lead, capacitance increases
• Most standard certificated aircraft incorporate a dual ignition system with two individual magnetos, separate sets of wires, and two spark plugs per cylinder to increase reliability of the ignition system through redundancy
• As engine rpm increases, the ignition timing needs to advance.
• The center electrode is the hottest part of the spark plug because it is the part that is directly exposed to the combustion chamber
• the three basic components of primary ignition circuit consists of a set of contact breaker , a condenser, and an insulated coil.
• The voltage required to initially create the spark across the spark plug gap is known as the ignition voltage. This voltage is necessary for the spark plug to ignite the fuel-air mixture in the combustion chamber of an internal combustion engine.