Thermostatic valve device having non-linear flow characteristics

A thermally responsive fluid flow control valve device for the cooling system of an internal combustion engine for elimination of temperature fluctuations in the fluid during initial opening operation of the valve device comprising:

• a stationary valve member provided with a flat annular valve seat portion forming a fluid port having an upstream side and a downstream side, the flat annular valve seat portion being normal to the direction of fluid flow through the fluid port,
• a movable valve member having a closure portion having a cylindrical part and being normally in engagement with the flat annular valve seat portion and closing the fluid port, the movable valve member being movable from the valve seat member in a downstream direction,
• the stationary valve member having an annular flange encompassing the flat annular valve seat portion and forming a recess within which the flat annular valve seat portion is located and within which the closure portion of the movable valve member is movable, the annular flange extending in a downstream direction from the flat annular valve seat portion and having an outwardly sloping internal wall surface within the recess, the outwardly sloping internal wall surface being angular with respect to the cylindrical part of the closure portion of the movable valve member to provide a flow passage which gradually increases in dimension in the downstream direction so that initial movement of the movable valve member with respect to the stationary valve member in the downstream direction from the flat annular valve seat portion is non-linear with respect to the area of the fluid flow passage created and creates a small fluid flow passage between the annular flange and the closure portion of the movable valve member, and increased movement of the movable valve member in a downstream direction creates a gradually increasing fluid flow passage between the annular flange and the closure portion of the movable valve member until the closure portion of the movable valve member moves from the confines of the annular flange, further movement of the closure portion of the movable valve member in the downstream direction from the flat annular valve seat portion beyond the confines of the annular flange being linear with respect to the area of the fluid flow passage created and creating a greater flow passage between the annular flange and the closure portion of the movable valve member,
• thermally responsive actuator means, and
• means joining the thermally responsive actuator means to the movable valve member for movement thereof with respect to the stationary valve member.

A thermally responsive fluid flow control valve device for an internal combustion engine for elimination of temperature fluctuations in the fluid during initial opening operation of the valve device comprising:

• a stationary valve member provided with a flat annular valve seat portion forming a fluid port having an upstream side and a downstream side, the flat annular valve seat portion being at right angles to the direction of fluid flow through the fluid port,
• a movable valve member having a closure portion normally in engagement with the flat annular valve seat portion and closing the fluid port, the movable valve member being linearly movable from the flat annular valve seat portion in a downstream direction, the movable valve member having a closure portion which is provided with a peripheral cylindrical surface which is parallel to the direction of movement of the linearly movable valve member,
• the stationary valve member being provided with a wall encompassing the flat annular valve seat portion and extending therefrom on the downstream side of the flat annular valve seat portion, the wall having an internal surface which slopes outwardly from the flat annular valve seat portion to provide a gradually increasing flow passage in the downstream direction from the flat annular valve seat portion, the internal surface of the wall being angular with respect to the peripheral cylindrical surface of the closure portion of the movable valve member when the closure portion of the movable valve member is in engagement with the flat annular valve seat portion of the stationary valve member,
• initial movement of the movable valve member in a downstream direction from the flat annular valve seat portion thus creating a small fluid flow passage between the closure portion of the movable valve member and the flat annular valve seat portion and between the peripheral cylindrical surface of the closure portion of the movable valve member and the internal surface of the wall, increased movement of the movable valve member in the downstream direction creating a greater flow passage between the closure portion of the movable valve member and the internal surface of the wall, such increased movement of the movable valve member being non-linear in magnitude with respect to the magnitude of the area of the fluid flow passage created between the closure portion of the movable valve member and the internal surface of the wall until the movable valve member moves from the confines of the wall, increased movement of the movable valve member in the downstream direction beyond the wall being linear in magnitude with respect to the magnitude of the area of the fluid flow passage created between the closure portion of the movable valve member and the wall,
• thermally responsive actuator means, and
• means joining the thermally responsive actuator means to the movable valve member for movement thereof with respect to the stationary valve member.