Heat exchanger and installation of heating or cooling of the motor vehicle containing

The invention relates to a plate heat exchanger type of construction of heat, with first flow channels (18) each formed of a pair of plates (16) for a first fluid, and fins or corrugated ribs (20) disposed between pairs of plates (16) each time neighboring, ribs or vanes swept by a flow of a second fluid. To provide an improved heat exchanger which allows to have a more compact construction of installation when used in a heating or air conditioning of vehicle, it is proposed that the corrugated ribs (20) and at least one of the pairs of plates (16) are adjacent the second flow passages (22) for the second fluid, and that the second flow channels (22) have a curvilinear shape, so that the second fluid undergoes a change flow direction, passes through the heat exchanger (10).