hehkutulppasytytystä

Hehkutulppasytytys, also known as glow plug ignition, is a method used to ignite fuel in some types of internal combustion engines, most notably diesel engines and certain small gasoline engines. Instead of a spark plug, which generates a high-voltage spark to ignite a fuel-air mixture, a glow plug relies on heat. A glow plug is essentially a resistive heating element. When an electric current passes through it, the element heats up to a very high temperature, glowing red or orange.

In diesel engines, the glow plugs are typically located in the combustion chamber and are activated before starting the engine. The heat from the glow plug helps to preheat the air in the combustion chamber, which is crucial for igniting the diesel fuel, especially in cold conditions. Once the engine starts and the combustion chamber reaches its operating temperature, the glow plugs may no longer be necessary, although some systems can keep them on for a short period after starting to ensure smooth running.

Some simpler gasoline engines, particularly older or smaller ones like those found in some model aircraft or early motorcycles, have also utilized glow plug ignition. In these applications, the glow plug is heated externally by a battery or power supply, and its continued heat is sufficient to ignite the fuel-air mixture repeatedly as it enters the cylinder. This differs from spark ignition, which relies on an intermittent spark. The primary advantage of glow plug systems is their simplicity and reliability, particularly in applications where a high-voltage ignition system might be problematic or unnecessary.