AHI(After treatment Hydrocarbon Injection) tube is for diesel combustion burner systems.
To regenerate DPF for diesel engines, the exhaust temperature is raised by injecting fuel into the exhaust gas and igniting it, leading to the combustion of soot inside the DPF.
AHI tube is used in severe environments in which it is exposed to high temperatures; however, it's robust reliability is a result of utilizing stainless steel and the brazing technology that USUI has developed.