The Ignition System of Gasoline Engine
A gasoline engine runs on a mixture of fuel and air, which is ignited by a spark. The spark must be generated at the right time for the engine to run properly and efficiently. To accomplish this, gasoline engines are equipped with an ignition system. In a typical ignition system, the spark is delivered by a distributor, which is usually triggered by a camshaft-driven rotor. The rotor is mounted inside a metal cap containing multiple points or contacts which complete the electrical circuit when the rotor spins past them in the correct sequence. Inside the cap there is also a coil, an electronic module, and a set of high-tension wires.
The coil is powered by the engine’s battery. When it’s triggered, a large voltage is produced, which is fed through the module, to the contact points, and then to the spark plugs. The high-tension wires then deliver the spark to the spark plugs, which ignite the air/fuel mixture and cause the engine to run.
The timing of the spark generation is handled by the electronic module, either via an electronic spark control system in newer vehicles or by a mechanical centrifugal advance system in older vehicles. The centrifugal advance system, which is operated by the rotor as it turns, advances the timing when the engine speed increases. This ensures that the spark is delivered at just the right time for optimal efficiency.
The distributor also houses a two-wire Hall-effect sensor, a device which measures the speed and position of the spinning rotor. This information is used by the module to precisely control the timing and keep the engine running smoothly. In addition, the Hall-effect sensor can be used to monitor the running condition of the engine and detect malfunctions.
At the heart of the distributor is the rotor, which consists of a magnet, a series of copper contacts, and a shaft that is driven by the camshaft. As the rotor spins, the magnet creates a small electric current in the copper contacts, which is sent to the module. The module then detects this signal, and triggers the coil, firing the spark plugs in the appropriate order.
The ignition system of a gasoline engine is a complex system, requiring precise timing to ensure that the spark is delivered at just the right time. Without it, the engine will not run efficiently, and may even fail to start. Through proper maintenance, the ignition system can be kept in top working condition and ensure that the engine is always running its best.
