Bosch's revolutionary Duraterm glow plug technology utilizes a self-regulating control system that reduces glow wait time by more than 50 percent. The patented dual-control regulating and heating coil effectively directs current draw, enabling the glow plug to reach higher temperatures more quickly for faster engine start-up, and the regulating coil keeps the heating element within the 1000 – 1100 degrees C optimal temperature range, preventing engine damage due to over voltage or overheating.
"The advanced Duraterm glow plug provides a 'post-glow' heating phase for vehicles with a 'post-glow' control system," said Ross Sandercock, Bosch Director of Product Management. "In the post-glow phase, glow plugs continue to operate for up to three minutes after the engine has started, improving overall engine performance and reducing smoke emissions and combustion noise."
This 'post glow' ability, built into the Duraterm glow plug, is a key element in Duraterm's contributing to increased diesel engine efficiency, according to Sandercock.
Operating Within Safe Temperature Range Essential
Glow plugs are designed to operate within a temperature range of 850 – 1100 degrees C. During operation, the glow plug controller switches current to the glow plug for a specific period of time to allow for proper heating. However, if the controller fails, current could be applied for a longer than specified time raising the temperature of the glow plug in excess of the 1100 degrees C upper limit. Under these conditions, the glow plug overheats causing the casing to swell, split or burst, which allows air to enter the coil area, causing immediate glow plug failure.
"Duraterm glow plugs prevent any overheating and potential engine damage with their built in self-regulating control system, avoiding the need to remove a glow plug with a distended or broken tip," Sandercock said. "This may require engine head removal — a time-consuming and costly repair."
Durability under the stress of extended diesel engine operation is essential for a glow plug, and Duraterm's glow tube material, Iconel 601, resists corrosion and vibration for long service life while fine-grained ceramic insulating powder provides superior electrical insulation and high thermal conductivity. Twin Viton seals protect coils from exhaust gas damage, and connectors are designed to OE specifications for precise fit and easy installation.
Duraterm technology is available for the majority of diesel car and light truck applications. Other applications utilize standard glow plug technology as called for by OE specifications.