Automotive coolant control valve

[0002] The present invention generally relates to a valve for controlling the flow of fluid and more particularly pertains to a valve for simultaneously controlling the distribution and flow of an automobile's coolant through multiple flow paths.

[0003] Water-cooled internal combustion engines that are used in automobiles rely on a fluid to carry excess heat from the engine to an external heat exchanger commonly referred to as the radiator. Such coolant is continuously recirculated through the engine until its temperature exceeds a preselected level at which point a portion of the flow is routed through the heat exchanger. The flow to the radiator is continuously adjusted in order to maintain the temperature of the coolant within a desired range. The heat carried by the fluid is also used to heat the interior of the automobile whereby a portion of the circulating coolant is routed through a second heat exchanger positioned so as to heat air that is directed into or recirculated within the passenger compartment.

[0004] The distribution of the flow of coolant that is generated by an engine-driven water pump is typically controlled by two separate components, namely a radiator thermostat and a heater valve. Heretofore used thermostats typically rely on a mechanism that causes the force generated by the expansion of mass of wax-like material to overcome the bias of a spring to open a valve wherein the wax-like material expands as a function of temperature. The entire device is immersed in the flow of coolant and is positioned and configured so as to block off the flow of coolant to the radiator when the valve is closed. While the valve is in its closed position, the coolant continues to circulate but is forced to bypass the radiator and is redirected back into the engine's water passages. A number of disadvantages are associated with this type of configuration including, but not limited to, the fact that the bypass flow path remains open at all times and that a portion of the flow of coolant therefore always bypasses the radiator even if maximum cooling is called for. Additionally, the positioning of the thermostat directly in the flow path of the coolant poses an impediment to the flow of coolant and thereby compromises the efficiency of the cooling system while the failure of the opening mechanism typically results in the thermostat remaining in its closed configuration which can quickly lead to engine damage. Another disadvantage inherent in heretofore used thermostat configurations is the fact that the device can necessarily only respond to the temperature of the coolant rather than directly to the temperature of the engine, let alone the anticipated cooling needs of the engine. The engine temperature may therefore not necessarily be optimized for a variety of conditions which may result in decreased fuel efficiency and increased exhaust emissions.

[0005] Heater valves are typically positioned so as to direct a portion of the flow of coolant to a heater core positioned within the HVAC system of the automobile. Early heating systems included a valve that was simply actuated by a cable extending from a lever positioned in the interior of the automobile. Many modern systems employ computer controlled servo operated valves, wherein the valve position is either modulated so as to control the temperature of the heater or subject to either a fully open or fully closed position wherein air heated by the heater is subsequently mixed with cooled air to regulate the temperature within the passenger compartment.

[0006] A difficulty associated with this heretofore approach toward controlling the flow and distribution of coolant is inherent in the fact that, in effect, two independently operating systems are affecting the temperature of a common coolant. A change in the demand for heat within the passenger cabin will effect the temperature of the coolant as will the position of the thermostat. A change in one will necessarily induce a change in the other and without a common control system, the temperature may tend to fluctuate and dither. Variations in engine load, especially in for example in stop-and-go traffic will introduce even more fluctuation as the heat fed into the system will additionally be subject to variation. Increasingly strict emission regulations and demands for higher fuel efficiencies require the engine to operate in narrower temperature ranges which requires a more precise control of coolant temperature. An improved cooling system is needed with which coolant temperature and hence engine and heater temperature can be more precisely controlled.

[0007] The valve of the present invention overcomes the shortcomings of previously known coolant flow and distribution control systems. A single valve replaces the presently used separate thermostat and heater valve devices and provides for the comprehensive control of the routing and flow of circulating coolant. The valve controls the flow of coolant to the radiator, the amount of flow that bypasses the radiator to be reintroduced into the engine's cooling passages, the flow of coolant to the heater and additionally provides for the degassing of the coolant flowing through the valve. All such functions are achieved by a single valve as described herein.

[0008] The valve of the present invention includes a valve rotor that is rotationally received within a valve housing. The housing includes an inlet and a number of outlet ports formed therein while the valve rotor has a number of conduits extending therethrough that serve to set the inlet port into fluid communication with a selected combination of outlet ports as a function of the rotational orientation of the valve rotor within the valve housing.

[0009] More particularly, the valve of the present invention is configured such that the ports that are formed in the cylindrical valve housing are arranged along at least two planes that are spaced along the axis of the housing. A first plane may include the inlet port and an outlet port for flow to the radiator. Ports arranged along a second plane may include a heater outlet port and a bypass port. A port for carrying gas bubbles may be formed in an end of the cylindrical housing. The conduits formed in the valve rotor are arranged such that selected conduits become aligned with selected ports as a function of the rotational orientation of the valve rotor within the valve housing. An internal conduit extends along the axis of the valve rotor so as to interconnect conduits that arranged along the two planes.

[0010] The precise rotational orientation of the valve rotor within the valve housing required to achieve a certain distribution and flow of coolant may be achieved by the operation of a stepper motor. Inputs received from one or more temperature sensors and from an operator with regard to a selected heater temperature may be interpreted by a microprocessor to generate a signal necessary to drive the motor to a desired position. A mechanical spring may additionally be employed to force the valve rotor to assume a rotational orientation for providing maximum flow to the radiator and heater in the event a failure of the electronics takes place to serve as a fail safe mode.

[0011] These and other features and advantages of the present invention will become apparent from the following detailed description of a preferred embodiment which, taken in conjunction with the accompanying drawings, illustrates by way of example the principles of the invention.

[0012] FIG. 1 is a perspective view of a valve assembly that includes a preferred embodiment of the valve of the present invention;

[0013] FIG. 2 is a perspective view of the valve;

[0014] FIG. 3 is a perspective view of the valve rotor;

[0015] FIG. 4 is a cross-sectional view of the valve rotor taken along lines 4—4 of FIG. 3;

[0016] FIG. 5 is a cross-sectional view of the valve rotor taken along lines 5—5 of FIG. 3;

[0017] FIG. 6 is a bottom plan view of the valve rotor shown in FIG. 3;

[0018] FIG. 7 is an enlarged cross-sectional view taken along lines 7—7 of FIG. 2;

[0019] FIG. 8 is a cross-sectional view of the valve rotor within the valve housing taken along the same plane as illustrated in FIG. 4 and rotated to its maximum counter-clockwise rotational orientation;

[0020] FIG. 9 is a cross-sectional view of the valve rotor within the valve housing taken along the same plane as is illustrated in FIG. 5 and in the same rotational orientation of the valve rotor vis-a-vis the valve housing as is shown in FIG. 8;

[0021] FIG. 10 is a cross-sectional view of the valve rotor within the valve housing taken along the same plane as illustrated in FIG. 4 and in its maximum clockwise rotational orientation;

[0022] FIG. 11 is a cross-sectional view of the valve rotor within the valve housing taken along the same plane as is illustrated in FIG. 5 and in the same rotational orientation of the valve rotor vis-a-vis the valve housing as is shown in FIG. 10; and

[0023] FIG. 12 is a graphic representation of the various flow paths as a function of rotational orientation.

[0024] The valve of the present invention replaces a conventional radiator thermostat and heater valve that are typically employed in modern automobiles. The valve controls the flow and distribution of coolant to the radiator, radiator bypass and heater and may optionally control the degassing of the coolant.

[0025] FIG. 1 is a perspective view of a valve assembly 12 that includes the valve 14 of the present invention. The valve controls the flow of coolant therethrough, wherein coolant entering through inlet port 16 is distributed via a preselectable combination of outlet ports 18, 20, 22, 24. Setting the inlet port into fluid communication with a desired combination of outlets ports is achieved via the operation of an associated drive mechanism 26 which may take the form of a stepper motor and reduction gear combination.

[0026] FIG. 2 is a perspective view of the valve 14 sans drive mechanism. The valve includes a valve rotor 28 that is rotationally received within a valve housing 30. The valve housing has a plurality of ports formed therein, including an inlet port 16, a radiator port 18, a bypass port 20, a heater port 22 and a degassing port 24. Each of the ports extend through the wall of the housing to define a conduit to its interior. The axis 32 of the inlet port and the axis 34 of the radiator port are aligned with one another and lie on a first plane that is perpendicular to the central axis 36 of the cylindrical valve. The axis 38 of the bypass port and the axis 40 of the heater port lie on a second plane that is perpendicular to the central axis wherein such second plane is axially displaced relative to the first plane. The axis 42 of the degassing port extends from the base of the valve housing, is generally parallel to the central valve axis 36 and radially offset therefrom. In the embodiment illustrated, each of the ports has a length of barbed tubing 43, 44, 45 of appropriate length and diameter extending therefrom configured for receiving a coolant carrying hose or line that may be fitted and clamped thereto. The rotational orientation of the valve rotor within the valve housing determines which outlet ports are set into fluid communication with the inlet port. A shaft 46 extends from one end of the valve rotor along its axis 36 to facilitate its rotation by the drive mechanism. A return spring 47 disposed about the shaft serves to bias the valve rotor into a preselected rotational orientation relative to the valve housing.

[0027] FIG. 3 is a perspective view of the valve rotor 28 of the valve 14 of the present invention. The valve rotor has a number of internal fluid passages formed therein that are interconnected to one another within the interior of the valve rotor and to various openings 48, 50, 52 formed on the surface of the valve rotor. The openings are circumferentially as well as axially spaced relative to one another in precisely defined locations so as to become aligned with selected ports formed in the valve housing 30 at preselected rotational orientations of the valve rotor relative to the valve housing.

[0028] FIG. 4 is a cross-sectional view of valve rotor 28 taken along lines 4—4 of FIG. 3. Clearly visible is a T-shaped fluid passage 54 formed therein that extends through the interior of the valve rotor and to its surface via openings 48, 50 and 56. A central fluid passage 58 extends down along the central axis of the valve rotor. The rotational orientation of the valve rotor within the valve housing 30 will determine which of the openings 48, 50 and 56 is to be set into fluid communication with radiator port 18 and what percentage of the cross-sectional area of such opening is to be aligned therewith.

[0029] FIG. 5 is a cross-sectional view of the valve rotor 28 taken along lines 5—5 of FIG. 3. The pie-shaped fluid passage 60 serves to set the central fluid passage into fluid communication with the elongated opening 52 formed on the surface of the rotor as well as with the small axially extending fluid passages 62, 64. The rotational orientation of the valve rotor within the valve housing 30 will determine whether the bypass port 20 or the heater port 22 or both ports are to be aligned with all or a portion of opening 52.

[0030] FIG. 6 is a bottom plan view of the valve rotor 28 showing the two grooves 66, 68 formed in the base of the component. The grooves are in fluid communication with fluid passages 62, 64 which extend into fluid passage 60. The rotational orientation of the valve rotor within the valve housing 30 will determine whether one of the grooves is set into fluid communication with the degassing port 24 formed in the base of the valve housing.

[0031] Seals are fitted about each of the outlet ports so as to limit the flow of fluid therethrough to only fluid that issues from an opening formed in the valve rotor 28 that is wholly or partially aligned therewith. FIG. 7 is an enlarged cross-sectional view taken along line 7—7 of FIG. 2 illustrating the seal configuration employed for heater port 22 which is identical to that which is employed for the radiator port 18 as well as the bypass port 20. Each of such ports includes a section of tubing 44 (or 43, 45) that extends outwardly and is configured for receiving and retaining a hose or other conduit clamped thereto. Each such section of tubing includes a neck portion 72 of reduced diameter disposed near its proximal end that terminates so as to be approximately aligned with the inner diameter of the valve housing 30. A flexible seal 70 includes a collar 74 is tightly fitted about the neck portion as well as a flange 76 that engages the surface of the valve rotor 28. The seal is configured such that the coolant which is present in the space 78 between the valve rotor and the valve housing serves to backload the seal so as to urge the flange against the valve rotor and thereby form an effective seal. A simple O-ring (not shown) serves to form a seal about the proximal end of the degassing port 24. A simple gasket (not shown) serves to form a seal between the upper flange 80 of the valve housing and a cooperating surface that may extend from the enclosure for the drive mechanism. An additional O-ring (not shown) is fitted about shaft 46 to form a seal with a cooperating surface of the enclosure for the drive mechanism to complete the seal of the valve housing.

[0032] In use, the valve of the present invention is plumbed such that the inlet port 16 receives the output from the water pump that is used to circulate an engine's coolant. The pump may comprise an engine driven or electrically driven device. The radiator port 18, bypass port 20 and heater port 22 are each plumbed to the respective components while the degassing port 24 is plumbed so as to most advantageously remove bubbles from the circulating coolant as is appropriate for a particular cooling system such as by connection to an overflow tank. Conventional hoses and hose clamps may be used to make the various connections. Any of a wide variety of control configurations may be employed to rotate the valve rotor 28 within the valve housing 30 in order to achieve a desired effect. A microprocessor receiving inputs from various sensors, including for example temperature sensors, as well as input from an operator, including for example a desired cabin temperature setting, determines which rotational orientation of the valve rotor within the valve housing would provide the appropriate amount of coolant flow through the various flow paths. The drive mechanism can then be provided with the appropriate signal in order to rotate the valve rotor into the proper orientation.

[0033] FIGS. 8 and 9 are cross-sectional views of a preferred embodiment of the valve of the present invention wherein the valve housing 28 is rotated to its extreme counter-clockwise position within the valve housing 30. FIG. 8 is a cross-sectional view along the plane that includes the axis 32 of the inlet port 16 and the axis 34 of the radiator port 18. FIG. 9 is a cross-sectional view along the plane that includes the axis 38 of the bypass port 20 and the axis 40 of the heater port 22. Fluid entering inlet port 16 is free to enter the valve rotor 28 through any of the unobstructed openings. While the most direct path is via opening 48, the gap 78 between the valve rotor and the valve housing also provides fluid paths to openings 50, 52 and 56. In this particular rotational orientation only a small percentage of one of the outlet ports, namely radiator port 18 is aligned with openings (50, 56) formed in the valve rotor. Radiator port seal 82 prevents unobstructed flow along gap 78 into the radiator port while bypass port seal 84 and heater port seal 86 precludes any flow into the respective ports.

[0034] FIGS. 10 and 11 are cross-sectional views of a preferred embodiment of the valve of the present invention wherein the valve housing 28 is rotated to its extreme clockwise position within the valve housing 30 which represents a rotation of approximately 225 degrees from the rotational orientation shown in FIGS. 8 and 9. FIG. 10 is a cross-sectional view along the plane that includes the axis 32 of the inlet port 16 and the axis 34 of the radiator port 18. FIG. 11 is a cross-sectional view along the plane that includes the axis 38 of the bypass port 20 and the axis 40 of the heater port 22. Fluid entering inlet port 16 is free to enter the valve rotor 28 through any of the unobstructed openings. While the most direct flow path is via opening 56, the gap 78 between the valve rotor and the valve housing also provides flow paths to openings 50 and 52. In this particular rotational orientation an unobstructed flow path is provided to both the radiator via opening 48 and radiator port 18 and to the heater via central fluid passage 58, opening 52 and heater port 22. Flow to the bypass port 20 is completely blocked off and sealed by bypass port seal 84. As such, this rotational orientation provides for maximum engine cooling and is used as a default or failsafe mode. In the event of a controller or other electrical malfunction, mechanical spring 47 serves to rotate the valve rotor into this orientation.

[0035] FIG. 12 is graphic representation of the various flow paths that are established as a function of the rotational orientation of the valve rotor 28 within the valve housing 30. The horizontal axis represents the rotational orientation of the valve rotor in degrees while the vertical axis represents the approximate open area that is available for the four different outlets. The radiator outlet is denoted by diamonds, the heater by the squares, the bypass by the triangles and the degas by the “X's”. The cross-sectional illustrations of FIGS. 8 and 9 are represented by the 0 degree position while the cross-sectional illustrations of FIGS. 10 and 11 are represented by the 225 degree position.

[0036] The valve configuration of the present invention allows a variety of different flow path combinations to be selected, including:

[0037] a. Bypass only with Degas closed;

[0038] b. Heater only with Degas closed;

[0039] c. Heater and Bypass open with Degas open;

[0040] d. Bypass open with Radiator blended and Degas open;

[0041] e. Heater open with Radiator blended and Degas open;

[0042] f. Radiator blended from 10% open to 100% open with Degas open; and

[0043] g. Radiator open, Heater open, Degas open and Bypass closed.

[0044] A controller can be configured to select various rotational orientations pursuant to various scenarios and conditions. Examples of such scenarios and conditions and the corresponding orientational selections include the following (wherein the index numbers correspond to the boxed numbers shown in FIG. 12):

[0045] The valve of the present invention may be formed from any of a variety of different materials. For example, the valve rotor may preferably be formed of an acetal copolymer known as celcon while the valve housing may be formed of a nylon thermoplastic. Other plastics may alternatively be used. As a further alternative, a metal may be used in the fabrication of one or both of the major components.

[0046] While a particular form of the invention has been illustrated and described, it will also be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention. The valve may be adapted for use in any of a variety of water-cooled engines, may be mounted in any of a variety of spatial orientations, including but not limited to an inverted orientation, may used with any of a variety of devices for selecting rotational orientations based on a multitude of inputs while the valve rotor may be rotated into position with any of a variety of drive mechanisms. Accordingly, it is not intended that the invention be limited except by the appended claims.