Oil cooler

Abstract

An oil cooler includes a heat exchanger core having a plurality of plates laid one upon another to define each of an oil passage through which oil flows and a coolant passage through which coolant flows, between the plates. An uppermost plate of the plates has a core coolant inlet and a core coolant outlet. The core coolant inlet and the core coolant outlet are communicated with the coolant passage. A flow passage control valve is disposed on an uppermost part of the heat exchanger core and has a first coolant introduction opening through which coolant at a relatively high temperature is supplied and a second coolant introduction opening through which coolant at a relatively low temperature is supplied. The first coolant introduction opening and the second coolant introduction opening are changed over to be communicated with the core coolant inlet.

What is claimed is: 
     
         1 . An oil cooler comprising:
 a heat exchanger core including a plurality of plates laid one upon another to define each of an oil passage through which oil flows and an coolant passage through which coolant flows, between the plates, the plates including an uppermost plate which has a portion defining a core coolant inlet and a portion defining a core coolant outlet, the core coolant inlet and the core coolant outlet being communicated with the coolant passage; and   a flow passage control valve disposed on an uppermost part including the uppermost plate, of the heat exchanger core and including a portion defining a first coolant introduction opening through which coolant at a relatively high temperature is supplied and a portion defining a second coolant introduction opening through which coolant at a relatively low temperature is supplied, the relatively high temperature being higher than the relatively low temperature, the first coolant introduction opening and the second coolant introduction opening being changed over to be communicated with the core coolant inlet.   
     
     
         2 . An oil cooler as claimed in  claim 1 , wherein the flow passage control valve includes a portion defining a coolant outlet opening communicated with the core coolant outlet of the heat exchanger core, at least one of the first and second coolant introduction openings being communicable with the coolant outlet opening to allow the coolant from at least one of the coolant introduction opening to bypass the heat exchanger core so as to be flown to the coolant outlet opening. 
     
     
         3 . An oil cooler as claimed in  claim 2 , wherein the flow passage control valve includes a rotary valve including a section defining four ports which are respectively communicated with the first coolant introduction opening, the second coolant introduction opening, the core coolant inlet and the coolant outlet opening, and a rotatable valve member for changing over from a communication between at least two of the four ports to another communication between at least two of the four ports in accordance with a rotating position thereof. 
     
     
         4 . An oil cooler as claimed in  claim 3 , wherein the valve member has its intermediate position at which coolant supplied from one of the first and second coolant introduction openings is dividedly flown to the core coolant inlet and the coolant outlet opening. 
     
     
         5 . An oil cooler as claimed in  claim 2 , wherein the flow passage control valve includes a valve housing including a cover section installed on the uppermost part of the heat exchanger core and located to cover the core coolant outlet, the cover section forming thereinside a bypass passage extending from the first and second coolant introduction openings to the coolant outlet opening, the bypass passage being communicated with core coolant outlet of the heat exchanger core. 
     
     
         6 . An oil cooler for a vehicle having an internal combustion engine, comprising:
 a hear exchanger core including a plurality of plates laid one upon another to define each of an oil passage through which oil flows and an coolant passage through which coolant flows, between the plates, the oil flow passage and the coolant flow passage being adjacent to each other through the plate, the plates including an uppermost plate which has a portion defining a core coolant inlet and a portion defining a core coolant outlet, the core coolant inlet and the core coolant outlet being communicated with the coolant passage; and   a flow passage control valve disposed on an uppermost part including the uppermost plate, of the heat exchanger core and including a portion defining a first coolant introduction opening to which coolant at a relatively high temperature is supplied from a water jacket of the engine, a portion defining a second coolant introduction opening to which coolant at a relatively low temperature is supplied from a radiator of the engine, the relatively high temperature being higher than the relatively low temperature, and a valve member for accomplishing a changeover between a first communication of the core coolant inlet with the first coolant introduction opening and a second communication of the core coolant inlet with the second coolant introduction opening, in accordance with an operating condition of the engine.