Vehicle heat exchanger tube and vehicle radiator comprising such a tube

1. A vehicle heat exchanger tube comprising an internal reinforcement structure, the vehicle heat exchanger tube comprising at least a first and a second separate fluid channel extending along the tube and being parallel with each other and being separated from each other by at least one separating wall extending along at least a portion of the tube, each fluid channel having an inner height and an inner width, the inner height measured in a direction being parallel with a height of the separating wall, the inner height being smaller than the inner width, the first channel having a first large surface, and an opposing second large surface, the second channel having a first large surface, and an opposing second large surface, wherein the internal reinforcement structure is a tube stiffener having a first stiffening portion stiffening the first channel of the tube, and a second stiffening portion stiffening the second channel of the tube, wherein the first and second stiffening portions of the tube stiffener are joined to each other at a joining portion, wherein the first stiffening portion comprises a first supporting surface supporting the first large surface of the first channel, a second supporting surface supporting the second large surface of the first channel, and an intermediate portion connecting the first supporting surface to the second supporting surface, and wherein the second stiffening portion comprises a first supporting surface supporting the first large surface of the second channel, a second supporting surface supporting the second large surface of the second channel, and an intermediate portion connecting the first supporting surface to the second supporting surface, wherein the tube comprises an inlet or outlet end portion at which the separating wall has been discontinued such that the first and second channels combine within the tube at said end portion, wherein the tube stiffener is at least partly received in said end portion such that the joining portion of the tube stiffener is arranged to be inserted into the inlet or outlet end portion at which the separating wall has been discontinued, and wherein the joining portion of the tube stiffener is provided with a cut-out that receives at least a portion of the separating wall, and wherein the first stiffening portion of the tube stiffener extends into the first channel at least partly into the tube where the first and second channels are separated from each other by the separating wall, and wherein the second stiffening portion of the tube stiffener extends into the second channel at least partly into the tube where the channels are separated from each other by the separating wall.

2. A tube according to claim 1 , wherein at least one of the large surfaces is provided with surface structures, and wherein said inlet or outlet end portion of the tube is essentially free from such surface structures.

3. A tube according to claim 1 , wherein the total length of the tube stiffener, as seen along the tube, is less than 20% of the total length of the tube.

4. A tube according to claim 1 , wherein the tube stiffener is made from a sheet metal, and wherein a material thickness of the tube stiffener is less than 30% of the inner height, which is measured in a direction being parallel with the height of the separating wall, of the first and second channels.

5. A tube according to claim 1 , wherein the first stiffening portion comprises an edge supporting surface supporting an edge surface connecting the first and second large surfaces of the first channel, and wherein the second stiffening portion comprises an edge supporting surface supporting an edge surface connecting the first and second large surfaces of the second channel.

6. A tube according to claim 1 , wherein the tube stiffener is brazed to the first and second channels.

7. A tube according to claim 1 , wherein at least one first inlet channel is formed between the first stiffening portion of the tube stiffener and one of the large surfaces of the first channel, and at least one second inlet channel is formed between the second stiffening portion of the tube stiffener and one of the large surfaces of the second channel.

8. A tube according to claim 1 , wherein the tube stiffener is entirely received inside the tube.

9. A vehicle radiator, comprising at least one vehicle heat exchanger tube according to claim 1 .

10. A vehicle radiator according to claim 9 , the vehicle radiator comprising a plurality of vehicle heat exchanger tubes, wherein less than 50% of the total number of vehicle heat exchanger tubes comprise tube stiffeners.

11. A method of forming a vehicle heat exchanger tube, the method comprising:

forming a tube comprising at least a first and a second separate fluid channel extending along the tube and being parallel with each other and being separated from each other by at least one separating wall extending along at least a portion of the tube, each fluid channel having an inner height and an inner width, the inner height measured in a direction being parallel with a height of the separating wall, the inner height being smaller than the inner width, the first channel having a first large surface, and an opposing second large surface, the second channel having a first large surface, and an opposing second large surface, wherein the tube is provided with an inlet end portion or an outlet end portion in which the separating wall has been discontinued which allows the first and second separate fluid channels to be combined within the tube,

forming a tube stiffener having a first stiffening portion intended for stiffening the first channel of the tube, and a second stiffening portion intended for stiffening the second channel of the tube, wherein the first and second stiffening portions of the tube stiffener are joined to each other at a joining portion, the joining portion of the tube stiffener including a cut-out configured to receive at least a portion of the separating wall, and

inserting the joining portion of the tube stiffener into the inlet end portion or the outlet end portion in which the separating wall has been discontinued, wherein a first supporting surface of the first stiffening portion extends into the first channel at least partly into the tube where the first and second channels are separated from each other by the separating wall to support the first large surface of the first channel, and a second supporting surface of the first stiffening portion extends into the first channel at least partly into the tube where the first and second channels are separated from each other by the separating wall to support the second large surface of the first channel, and wherein a first supporting surface of the second stiffening portion extends into the second channel at least partly into the tube where the first and second channels are separated from each other by the separating wall to support the first large surface of the second channel, and a second supporting surface of the second stiffening portion extends into the second channel at least partly into the tube where the first and second channels are separated from each other by the separating wall to support the second large surface of the second channel.

12. A method according to claim 11 , further comprising exposing, after inserting the tube stiffener into the tube, the tube and the tube stiffener to a brazing to fix the tube stiffener to the tube.