Ceramic glow plugs

As opposed to a metal pin-type glow plug, the heating coil of a ceramic glow plug has an especially high melting point. It is also sheathed in silicon nitrite, an extremely robust ceramic material. The combination of the heating coil and ceramic sheath enable higher temperatures and extremely short preheat times due to excellent thermal conductivity. Also, ceramic glow plugs have a more compact design. This is important, because there is very little free space in today’s engines.



In an SRC (Self Regulating Ceramic) glow plug the heating element is made of ceramic with a sintered metal heating coil. An HTC (High Temperature Ceramic) or NHTC (New High Temperature Ceramic) glow plug has a heating element and a heater made of ceramic.

The NHTC ceramic glow plug was specially developed by NGK to enable automobile manufacturers to comply with the Euro 4 and Euro 5 emissions standards. One of the goals of these standards is to reduce the compression ratio in diesel engines. NHTC glow plugs achieve a temperature of 1,000°C in less than two seconds and can after-glow for more than ten minutes at temperatures of up to 1,350°C. Optimum combustion is ensured even at low compression ratios. In addition, the NHTC glow plug can glow intermediately to prevent cooling of the particle filter in deceleration phases.