What component is commonly used in a Hot Surface Ignition (HSI) system for ignition?

In a Hot Surface Ignition (HSI) system, a silicon carbide rod is commonly used for ignition due to its ability to reach high temperatures and maintain those temperatures for effective ignition of gas fuel. The silicon carbide material is highly conductive and can generate a significant amount of heat quickly when an electrical current passes through it. This characteristic makes it ideal for lighting gas burners by glowing red hot, thus igniting the gas as it flows into the combustion chamber.

While other ignition components, such as a metal heating element, tube igniters, or electric spark generators, serve distinct functions in different types of ignition systems, they do not provide the same level of reliability and efficiency as a silicon carbide rod in HSI applications. Metal heating elements may not heat up sufficiently to ignite gas directly, tube igniters are generally used in different contexts (like in gas or propane torches), and electric spark generators perform well in piezoelectric or intermittent ignition systems but do not rely on the high-temperature surface needed for constant ignition as HSI systems do.