Electrical heating device for preheating of the fuel of internal combustion engines, especially diesel engines

摘要

The screw head (7) of a hollow screw (5), as is conventionally used for connecting the fuel feed line (1) to a fuel filter, is bored and a conventional sheathed-element glow plug (15) fitted into this bore (14) in such a way that the glow element (16) extends concentrically into the longitudinal bore (14) of the hollow screw (5). This modified hollow screw (5) is directly fitted into the filter housing (2) and connected to a voltage source by way of a control device (40). For controlling the heating of the liquid fuel, a temperature sensor (12) is arranged in direct thermal contact with the hollow screw (5), so that the temperature detected by the temperature sensor (12) does not vary as a function of the temperature of the heated fuel. Prompt shutting off of the sheathed-element glow plug (15) is thereby ensured before liquid fuel can vaporise. Due to the fitting of the hollow screw (5) directly into the filter housing (2) and the connection of good thermal conductivity between sheathed-element glow plug (15) and hollow screw (5) on the one hand and hollow screw (5) and filter housing (2) on the other, not only the liquid fuel but also the filter housing (2) is directly heated. <IMAGE>