Fuel mixture heating device of an internal combustion engine

A fuel mixture heating device of an internal combustion engine having an intake manifold and an intake passage which has an outlet connected to a collecting portion of the intake manifold, the intake passage having a fuel feed apparatus for feeding fuel into the intake passage, said device comprising:

• a power source, and
• a hollow cylindrical heater vessel arranged at the outlet of the intake passage and having an outlet portion which projects into the collecting portion of the intake manifold, said heater vessel comprising a hollow cylindrical inner pipe, a hollow cylindrical outer pipe made of a heat insulating material, and a heater element connected to said power source, said heater element being between said inner pipe and said outer pipe and directly contacting both said inner pipe and said outer pipe, said inner pipe being aligned with the intake passage and having a uniform inner diameter throughout its length which is substantially the same as that of the intake passage whereby the inner pipe transmits heat to the fuel mixture in order to vaporize it and acts as an electrode, while the outer pipe acts as a heat insulator.