Heat exchanger for vehicle

A heat exchanger for a vehicle, comprising:

• a heat radiating portion provided with first and second connecting lines formed alternately by stacking a plurality of plates, and receiving first and second operating fluids respectively into the first and second connecting lines, the first and second operating fluids heat-exchanging with each other during passing through the first and second connecting lines;
• and
• a bifurcating portion connecting an inflow hole for flowing one operating fluid of the first and second operating fluids with an exhaust hole for exhausting the one operating fluid, wherein the bifurcating portion is adapted for the one operating fluid to bypass the heat radiating portion according to a temperature of the one operating fluid, and mounted at an exterior of the heat radiating portion,
• wherein the first operating fluid flows into the heat radiating portion through a first inflow hole and flows out from the heat radiating portion through a first exhaust hole, and the first inflow hole is connected to the first exhaust hole through the first connecting line,
• wherein the second operating fluid flows into the heat radiating portion through a second inflow hole and flows out from the heat radiating portion through a second exhaust hole, and the second inflow hole is connected to the second exhaust hole through the second connecting line,
• wherein the first and second inflow holes are formed at both sides of a surface of the heat radiating portion along a length direction of the heat radiating portion, and
• the first and second exhaust holes are distanced from the first and second inflow holes and are formed at the both sides of the surface of the heat radiating portion along the length direction of the heat radiating portion,
• wherein the bifurcating portion comprises:
• a connecting pipe connecting the first inflow hole with the first exhaust hole at the exterior of the heat radiating portion, and having an inflow port formed at a position closer to the first inflow hole than to the first exhaust hole and an exhaust port confronting the inflow port and formed at a position closer the first exhaust hole than to the first inflow hole, and
• a valve unit mounted at one end portion of the connecting pipe between the first inflow hole and the inflow port, and adapted to extend or contract according to the temperature of the operating fluid to selectively close the first inflow hole, wherein the operating fluid flowing in through the inflow port flows directly to the exhaust port when the first inflow hole is closed by the valve unit, or flows into the first inflow hole of the heat radiating portion when the first inflow hole is opened by the valve unit,
• wherein the valve unit comprises
• a mounting cap fixedly mounted to one end of the connecting pipe closer to the first inflow hole than to the first exhaust hole, and
• a deformable member having a first end portion connected to the mounting cap inserted in the connecting pipe and a second end portion disposed outside the mounting cap, and adapted to extend or contract according to the temperature of the operating fluid and selectively close the first inflow hole, wherein the deformable member is formed by overlapping and contacting a plurality of ring members with each other in a coil spring shape, and
• wherein, when neighboring ring members directly contact each other in response to the temperature of the operating fluid decreasing, the operating fluid flowing into the inflow port flows directly to the exhaust port when neighboring ring members of the ring members directly contact each other such that a gap between the neighboring ring members is closed and contacted neighboring ring members physically seal the first inflow hole and the operating fluid flowing into the inflow port flows directly to the exhaust port, and wherein, when the neighboring ring members are spaced apart from each other in response to the increasing temperature of the operating fluid, the operating fluid flowing into the inflow port flows into the first inflow hole through the gap formed between spaced neighboring ring members.