Patent ID: 6138617
Filing Date: 2000-10-31
Classification: F01P,G05D

Abstract:
A cooling system for an automotive engine comprising:a radiator for cooling a coolant of the automotive engine;a cooling fan driven by a motor for cooling the coolant in the radiator;a first coolant passage provided between an outlet of a water jacket of the engine and an inlet of the radiator;a second coolant passage provided between an outlet of the radiator and an inlet of the water jacket;a bypass passage communicating the first coolant passage and the second coolant passage with each other;a housing provided at an intersection of the second coolant passage and the bypass passage;a rod secured to the housing;a guide member slidably mounted on the rod;a resilient seal spool enclosing the rod and hermetically engaged with the guide member at a base portion thereof;a lubricant oil sealed in a space between the rod and the seal spool;a heat sensitive cylinder enclosing the guide member and the seal spool;wax pellets sealed in the heat sensitive cylinder;a main valve secured to the guide member so as to close the second coolant passage;a bypass valve secured to the heat sensitive cylinder so as to close the bypass passage;a flange having a valve seat and secured to the housing;a return spring urging the main valve to the valve seat; andcoolant pressure being applied to inside and outside surfaces of the flange when the main valve closes the second coolant passage;wherein;the thickness of the seal spool at a portion engaging with the rod is 25% to 5% of the diameter of the rod;at least one hole is formed in the flange;a cooling fan switch is provided for detecting the temperature of the coolant, and provided to be closed at a predetermined temperature;the thickness of the seal spool and the spring constant of the return spring are selected so that the operating of the main valve is within a temperature range in which the wax pellets change from a solid state to a liquid state; andthe predetermined temperature for closing the cooling fan switch is set to a value so that an upper limit of the coolant temperature is limited within a range in which the wax pellets change from a solid state to a liquid state.