Patent Description:
Conventional automotive vehicles typically include a heating system for supplying warm air to a passenger compartment of the vehicle. The heating system includes a control system that allows a vehicle operator to regulate the quantity and/or temperature of air delivered to the passenger compartment to achieve a desirable air temperature within the passenger compartment. Cooling fluid from the vehicle's engine cooling system is commonly used as a source of heat for heating the air delivered to the passenger compartment.

The heating system typically includes a heat exchanger fluidly connected to the vehicle's engine cooling system. Warm cooling fluid from the engine cooling system passes through the heat exchanger and gives up heat to a cool air supply flowing through the heating system. The heat energy transferred from the warm cooling fluid to the cool air supply causes the temperature of the air to rise. The heated air is discharged into the passenger compartment to warm the interior of the vehicle to a desired air temperature.

The vehicle's engine cooling system provides a convenient source of heat for heating the vehicle's passenger compartment. One disadvantage of using the engine cooling fluid as a heat source, however, is that there is typically a significant delay between when the vehicle's engine is first started and when the heating system begins supplying air at a preferred temperature. This is particularly true when the vehicle is operated in very cold ambient conditions or has sat idle for a period of time. The delay is due to the cooling fluid being at substantially the same temperature as the air flowing through the heating system and into the passenger compartment when the engine is first started. As the engine continues to operate, a portion of the heat generated as a byproduct of combusting a mixture of fuel and air in the engine cylinders is transferred to the cooling fluid, causing the temperature of the cooling fluid to rise. Since, the temperature of the air being discharged from the heating system is a function of the temperature of the cooling fluid passing through the heat exchanger, the heating system will produce proportionally less heat while the engine cooling fluid is warming up than when the cooling fluid is at a preferred operating temperature. Thus, there may be an extended time between when the vehicle's engine is first started and when the heating system begins producing air at an acceptable temperature level. The time it takes for this to occur will vary depending on various factors, including the initial temperature of the cooling fluid and the initial temperature of the air being heated. It is preferable that the temperature of the cooling fluid reach its preferred operating temperature as quickly as possible.

Another potential limitation of using the engine cooling fluid as a heat source for the vehicle's heating system is that under certain operating conditions the engine may not be rejecting enough heat to the cooling fluid to enable the air stream from the vehicle's heating system to achieve a desired temperature. This may occur, for example, when operating a vehicle with a very efficient engine under a low load condition or in conditions where the outside ambient temperature is unusually cold. Both of these conditions reduce the amount of heat that needs to be transferred from the engine to the cooling fluid to maintain a desired engine operating temperature. This results in less heat energy available for heating the air flowing through the vehicle's heating system.

Accordingly, it is desirable to develop a heating system capable of intermittently providing additional heating of an engine's cooling fluid to improve the heating efficiency of the vehicles' passenger compartment heating system. <CIT> and <CIT> disclose hydrodynamic brake systems that are integrated in a liquid cooling circuit. The hydrodynamic brake systems each comprise a hydraulic retarder that receives cooled liquid from a heat exchanger, wherein heated cooling liquid is transported from the retarder to the heat exchanger during a braking action. <CIT> discloses a heater device that is fixed to a combustion engine. The heater device comprises an inlet port for receiving a cooling liquid, as well as an outlet port for heated cooling liquid. <CIT>, on which the two-part-form of claim <NUM> is based, discloses a hydrodynamic heater having a control valve and an outlet metering device on its outlet side as functional module for controlling the amount of heated cooling liquid that flows through the heater. It is the object of the present invention to provide a hydrodynamic heater that is operable more efficiently and more securely. This object is solved by a hydrodynamic heater according to claim <NUM>.

Disclosed is hydrodynamic heater operable for generating a stream of heated fluid. The hydrodynamic heater includes an inlet port for receiving a stream of fluid from an external source and an outlet port for discharging a stream of heated fluid from the hydrodynamic heater. The hydrodynamic heater includes a stator and a rotor positioned adjacent the stator. The stator and rotor together define a hydrodynamic chamber operable for heating a
fluid. The rotor is mounted to a drive shaft and rotatable relative to the stator. The hydrodynamic chamber operates to heat fluid present within an interior of the hydrodynamic chamber. The hydrodynamic chamber includes an inlet port located proximate a center of the interior region of the hydrodynamic chamber and an outlet port located along an interior wall of the hydrodynamic chamber. The hydrodynamic chamber inlet port is fluidly connected to the inlet port of the hydrodynamic heater. A fluid bypass passage is fluidly connected to both the inlet and outlet ports of the hydrodynamic chamber. An inlet fluid metering device is connected in series with the fluid bypass passage and the inlet port of the hydrodynamic chamber. Heated fluid from the hydrodynamic chamber is discharged from the outlet port of the hydrodynamic heater to the fluid bypass passage. An outlet fluid metering device may be connected in series with the fluid bypass passage and the outlet port of the hydrodynamic chamber. Power for rotating the drive shaft and rotor relative to the stator is provided by an external power source.

The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:.

Referring now to the discussion that follows, and also to the drawings, illustrative approaches are described in detail. Although the drawings represent some possible approaches, the drawings are not necessarily to scale and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain the present invention. Further, the descriptions set forth herein are not intended to be exhaustive or otherwise limit or restrict the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description.

Disclosed is a two-port hydrodynamic heater operable to selectively generate a stream of heated fluid. The hydrodynamic heater may be employed with a variety of systems requiring a source of heat. For example, the hydrodynamic heater may be incorporated into an automotive engine cooling system to provide primary or supplemental heat for heating a passenger compartment of a vehicle and/or provide other functions, such as windshield deicing. The hydrodynamic heater may be used in a wide variety of applications that utilize a heat source. Heated fluid discharged from the hydrodynamic heater may be used directly or in conjunction with one or more heat exchangers to provide a stream of heated fluid, such as stream of air. The hydrodynamic heater may function as a primary source of heat or operate to supplement heat provide by another heat source.

With reference to <FIG>, a two-port hydrodynamic heater <NUM> may include a generally toroidal-shaped hydrodynamic chamber <NUM> operable for heating a fluid present within the hydrodynamic chamber. Hydrodynamic chamber <NUM> may be enclosed within a housing <NUM>. The two-port hydrodynamic heater <NUM> includes an inlet passage <NUM> having an inlet port <NUM> and an outlet passage <NUM> having an outlet port <NUM>. Inlet passage <NUM> fluidly connects hydrodynamic chamber <NUM> to an external fluid source and outlet passage <NUM> provides a fluid outlet for outputting a stream of heated fluid generated when operating the two-port hydrodynamic heater <NUM>.

The hydrodynamic chamber <NUM> includes a stator <NUM> and a coaxially aligned rotor <NUM> positioned adjacent stator <NUM>. Stator <NUM> may be fixedly attached to housing <NUM>. Rotor <NUM> may be mounted on a drive shaft <NUM> for concurrent rotation therewith about an axis of rotation <NUM> relative to the stator <NUM> and housing <NUM>. Stator <NUM> and rotor <NUM> each include an annular cavity <NUM> and <NUM>, respectively, which together define hydrodynamic chamber <NUM>.

With reference to <FIG> and <FIG>, rotor <NUM> include a plurality of rotor blades <NUM> arranged circumferentially within annular cavity <NUM> of rotor <NUM>. Rotor blades <NUM> extend generally radially outward relative to the axis of rotation <NUM> and extend axially inward (i.e., toward a center of hydrodynamic chamber <NUM>) from an interior back wall <NUM> of rotor <NUM> to a front face <NUM> of rotor <NUM> located immediately adjacent stator <NUM>. Each rotor blade <NUM> includes a leading edge <NUM> located adjacent stator <NUM>. Rotor blades <NUM> may be inclined in direction opposite a direction of rotation <NUM> of rotor <NUM> from leading edge <NUM> to interior back wall <NUM> of rotor <NUM>. Rotor blades <NUM> and interior back wall <NUM> together define a plurality of bucket-shaped rotor cavities <NUM> circumferentially distributed within annular cavity <NUM> of the rotor <NUM>.

With Reference to <FIG> and <FIG>, stator <NUM> may include a plurality of stator vanes <NUM> arranged circumferentially within annular cavity <NUM> of stator <NUM>. Stator vanes <NUM> extend generally radially outward relative to the axis of rotation <NUM> and extend axially inward (i.e., toward a center of hydrodynamic chamber <NUM>) from an interior back wall <NUM> of the stator <NUM> to a front face <NUM> of stator <NUM> located immediately adjacent rotor <NUM>. Each stator vane <NUM> includes a leading edge <NUM> located adjacent rotor <NUM>. Stator vanes <NUM> may be inclined in the direction of rotation <NUM> of rotor <NUM> from leading edge <NUM> to the interior back wall <NUM> of stator <NUM>. Stator vanes <NUM> and the interior back wall <NUM> of the stator <NUM> together define a plurality of bucket-shaped stator cavities <NUM> circumferentially distributed within annular cavity <NUM> of stator <NUM>.

Power for rotatably driving rotor <NUM> when the two-port hydrodynamic heater <NUM> is activated is supplied by an external power source, for example, an internal combustion engine or electric motor. With reference to <FIG>, an end of drive shaft <NUM> may extend from housing <NUM> of the two-port hydrodynamic heater <NUM>. Drive shaft <NUM> may be coupled, for example, to an engine accessory drive belt driven by a crankshaft of the vehicle's engine. The accessory drive belt transfers torque generated by the vehicle engine to drive shaft <NUM> connected to rotor <NUM>.

With continued reference to <FIG>, inlet passage <NUM> fluidly connects inlet port <NUM> to a generally annular-shaped inlet plenum <NUM>. One or more stator supply passages <NUM> extend through stator vane <NUM> and fluidly connect inlet plenum <NUM> to hydrodynamic chamber <NUM>. Stator supply passages <NUM> exit stator vanes <NUM> at a hydrodynamic chamber inlet port <NUM> located proximate leading edge <NUM> of stator vane <NUM>. Hydrodynamic chamber inlet port <NUM> may be generally located at or near a toroid axis of revolution <NUM> of the toroidal-shaped hydrodynamic chamber <NUM>. <FIG> illustrates each stator vane <NUM> as including a supply passage <NUM> and a hydrodynamic chamber inlet port <NUM>; however, certain applications may employ fewer passages and ports. In certain applications, some of the stator vanes <NUM> may include supply passage <NUM> and hydrodynamic chamber inlet port <NUM>, while other stator vanes <NUM> may not. The total number of stator supply passages <NUM> and hydrodynamic chamber inlet ports <NUM> may vary depending on the design and performance requirements of a particular application.

With reference to <FIG> and <FIG>, hydrodynamic chamber <NUM> includes a hydrodynamic chamber outlet port <NUM> located along interior back wall <NUM> of stator <NUM>. The hydrodynamic chamber outlet port <NUM> may be positioned within an outermost half <NUM> of hydrodynamic chamber <NUM> generally extending from the toroid axis of revolution <NUM> to an outer circumference <NUM> of hydrodynamic chamber <NUM>. The hydrodynamic chamber outlet port <NUM> and the hydrodynamic chamber inlet port <NUM> may alternatively be located at a different locations along a periphery of the hydrodynamic chamber <NUM>, so long as the hydrodynamic chamber outlet port <NUM> is located at a radial distance from the axis of rotation <NUM> that is greater than a radial distance between the hydrodynamic chamber inlet port <NUM> and the axis of rotation <NUM>.

With particular reference to <FIG>, a hydrodynamic chamber outlet passage <NUM> may fluidly connect the hydrodynamic chamber outlet port <NUM> to a generally annular-shaped outlet plenum <NUM>. Outlet passage <NUM> may fluidly connect outlet plenum <NUM> to outlet port <NUM>.

According to the invention, inlet passage <NUM> includes an inlet fluid metering device <NUM> for controlling a flow rate of fluid passing through inlet passage <NUM> from inlet port <NUM> to inlet plenum <NUM>. Inlet fluid metering device <NUM> operates to control a flowrate of fluid from inlet port <NUM> to hydrodynamic chamber <NUM>.

Inlet fluid metering device <NUM> may have any of a variety of configurations. For example, inlet fluid meter device <NUM> may include an inlet metering orifice <NUM> having a predetermined configuration based on the design and performance requirements of the particular application. Inlet metering orifice <NUM> may include a generally fixed fluid thru-flow area that remains open to allow a continuous flow of fluid from inlet port <NUM> to hydrodynamic chamber <NUM>. Inlet metering orifice <NUM> may include, for example, an orifice plate or any other device capable of restricting a flow of fluid between inlet port <NUM> and hydrodynamic chamber <NUM>.

It should be understood that <FIG> merely illustrates an example of a fluid passage network that may be used to fluidly interconnect hydrodynamic chamber <NUM>, fluid metering device <NUM> and inlet and outlet ports <NUM> and <NUM>. Other alternately configured fluid networks may also be employed depending on the performance and design requirements of a particular application. Various fluid passages and/or combinations of fluid passages may be used to fluidly connect inlet port <NUM> to inlet fluid metering device <NUM> and inlet fluid metering device <NUM> to hydrodynamic chamber inlet port <NUM>. Any such alternately configured fluid network may be arranged within or separate from housing <NUM>. Regardless of the actual configuration of the fluid network employed, the fluid network passages should operate to fluidly connect inlet fluid metering device <NUM> in series with inlet port <NUM> and hydrodynamic chamber <NUM>.

The two-port hydrodynamic heater <NUM> may be integrated into a selected application by fluidly connecting inlet passage <NUM> and outlet passage <NUM> to a common external fluid source, such as, for example, an inlet heater hose <NUM>. Fluid entering the two-port hydrodynamic heater <NUM> from the external fluid source through inlet passage <NUM> is heated and discharged from the two-port hydrodynamic heater <NUM> through outlet passage <NUM>. Suitable hoses, pipes, tubes and various other fluid connections may be used to fluidly connect inlet port <NUM> and outlet port <NUM> to the associated components employed in the particular application.

When operating the two-port hydrodynamic heater <NUM>, fluid from the external fluid source (i.e., inlet heater hose <NUM>) enters the two-port hydrodynamic heater <NUM> at inlet port <NUM> and travel sequentially through inlet passage <NUM>, fluid metering device <NUM>, inlet plenum <NUM> and stator supply passage <NUM> to be discharged into hydrodynamic chamber <NUM> through hydrodynamic chamber inlet port <NUM>. Fluid present within hydrodynamic chamber <NUM> travels along a generally toroidal path in hydrodynamic chamber <NUM>, generating heat as the fluid travels back and forth between annular cavities <NUM> and <NUM> of stator <NUM> and rotor <NUM>, respectively. Fluid present in hydrodynamic chamber <NUM> continues to travel along the path between rotor <NUM> and stator <NUM> until being discharged from hydrodynamic chamber <NUM> through hydrodynamic outlet port <NUM>. The heated fluid passes through hydrodynamic chamber outlet passage <NUM> to outlet plenum <NUM>. Heated fluid exits outlet plenum <NUM> and passes through outlet passage <NUM> to outlet port <NUM>, where it may be discharged to the external fluid source (i.e., inlet heater hose <NUM>).

Performance of the two-port hydrodynamic heater <NUM> may be at least partially regulated by controlling the flow of fluid being heated in hydrodynamic chamber <NUM> and discharged through outlet port <NUM>. This may be accomplished by controlling the flow of fluid passing though inlet fluid metering device <NUM> from inlet port <NUM> to inlet plenum <NUM>. Increasing a thru-flow area of inlet metering orifice <NUM> of fluid metering device <NUM> will typically increase the amount fluid delivered to hydrodynamic chamber <NUM>, whereas decreasing the thru-flow will typically decrease the flowrate. The quantity of fluid passing through inlet fluid metering device <NUM> may depend in part on the configuration of inlet metering orifice <NUM> and the pressure drop occurring across fluid metering device <NUM>.

The two-port hydrodynamic heater <NUM> may be employed in a wide variety of applications to provide a supply of heat required for the particular application. For example, the two-port hydrodynamic heater <NUM> may be incorporated with an automotive vehicle cooling system to provide heat for warming a passenger compartment of the vehicle and to provide other capabilities, such as window deicing and engine cooling. An example of a typical automotive cooling system <NUM> is schematically illustrated in <FIG>. Vehicle cooling system <NUM> functions to regulate an operating temperature of an engine <NUM>. Cooling system <NUM> may include a water pump <NUM> operable to circulate a cooling fluid <NUM> through engine <NUM> to absorb excess heat produced by engine <NUM>. The excess heat is a byproduct of combusting a mixture of fuel and air in cylinders <NUM> of engine <NUM> to produce usable mechanical work for propelling the vehicle. Water pump <NUM> may be powered by an engine accessory drive <NUM> by way of a drive belt <NUM> that engages a sheave <NUM> attached to water pump <NUM>. Accessory drive <NUM> may be connected to a crankshaft (not shown) of engine <NUM>. The cooling fluid <NUM> may be circulated through passages in engine <NUM> where the cooling fluid <NUM> absorbs at least some of the excess heat. After circulating through engine <NUM>, the cooling fluid <NUM> may be discharged from engine <NUM> through an exit passage <NUM>. Depending on the temperature of the cooling fluid <NUM> exiting engine <NUM>, the cooling fluid may be directed back to water pump <NUM> through a bypass line <NUM> to be recirculated through engine <NUM>, or may be directed to a radiator <NUM> through a fluid line <NUM>.

A thermostat <NUM> operates to control distribution of the cooling fluid <NUM> between bypass line <NUM> and fluid line <NUM>. Thermostat <NUM> may be configured as a thermally activated valve capable of automatically adjusting its thru-flow area depending on a temperature of the cooling fluid <NUM> discharged from engine <NUM> through exit passage <NUM>. An automotive thermostat is one example of thermally activate valve. Automotive thermostats may be calibrated to begin opening at a predetermined cooling fluid temperature (measured within thermostat <NUM>), for example <NUM> degree Fahrenheit. At cooling fluid temperatures below the calibrated temperature, thermostat <NUM> may be fully closed to prevent cooling fluid from being supplied to radiator <NUM> through fluid line <NUM>. At temperatures at or slightly above the calibrated temperature, thermostat <NUM> begins opening to allow a portion of cooling fluid <NUM> from engine <NUM> to be directed to radiator <NUM>. At cooling fluid temperatures significantly higher than the calibrated temperature, thermostat <NUM> will be completely open to maximize the flow rate of cooling fluid <NUM> to radiator <NUM> for a particular vehicle operating condition.

Cooling fluid <NUM> passing through fluid line <NUM> enters radiator <NUM> through an inlet port <NUM>. Cooling fluid <NUM> flows through radiator <NUM> where the fluid rejects a portion of its heat to a stream of ambient air <NUM> flowing across radiator <NUM>. Cooling fluid <NUM> exits radiator <NUM> through an outlet port <NUM> at a lower temperature than the temperature of the cooling fluid entering radiator <NUM> at inlet port <NUM>. Upon exiting radiator <NUM> at outlet port <NUM>, cooling fluid <NUM> is directed to water pump <NUM> through a fluid line <NUM>.

An expansion tank <NUM> may be fluidly connected to water pump <NUM>. Expansion tank <NUM> provides a reservoir for capturing cooling fluid <NUM> discharged from cooling system <NUM> as the cooling fluid is heated, such as may occur when engine <NUM> is started after being turned off for a period of time. A portion of the excess cooling fluid <NUM> may also be withdrawn from expansion tank <NUM> and returned back to cooling system <NUM> when the temperature of the cooling fluid within cooling system <NUM> is decreased, such as may occur after engine <NUM> is turned off.

Conventional automotive vehicles may include a heating system <NUM> for providing a supply of warm air to heat a passenger compartment <NUM> of the vehicle. Heating system <NUM> may include a heat exchanger <NUM>, also known as a heater core, fluidly connected to cooling system <NUM> through inlet heater hose <NUM> and exit heater hose <NUM>. Inlet heater hose <NUM> may be fluidly connected to cooling system <NUM> through thermostat <NUM> and to heat exchanger <NUM> at in inlet port <NUM>. Exit heater hose <NUM> may be fluidly connected to an outlet port <NUM> of heat exchanger <NUM> and to water pump <NUM>. A portion of cooling fluid <NUM> exiting engine <NUM> at exit passage <NUM> passes through inlet heater hose <NUM> to heat exchanger <NUM>. Cooling fluid <NUM> rejects a portion of its heat to a stream of air <NUM> made to flow over heat exchanger <NUM>. Airstream <NUM> may include air drawn from outside the vehicle, from the passenger compartment <NUM> of the vehicle, or a combination thereof. Airstream <NUM> exits heat exchanger <NUM> at a higher temperature than when it entered. The warm airstream <NUM> may be discharged into passenger compartment <NUM> to warm the interior of the vehicle. The warm airstream <NUM> may also be directed to flow over an interior glass surface of the vehicle to remove frost or condensation that may have formed on the glass surface. Heating system <NUM> may also include various control devices for regulating a temperature and flow rate of airstream <NUM> being supplied to passenger compartment <NUM>.

Referring to <FIG>, a heating system <NUM> includes the two-port hydrodynamic heater <NUM> fluidly connected in parallel with inlet heater hose <NUM>. With this arrangement, a portion of the cooling fluid <NUM> received from cooling system <NUM> passes through the two-port hydrodynamic heater <NUM> prior to being delivered to heat exchanger <NUM>. Inlet passage <NUM> of the two-port hydrodynamic heater <NUM> is fluidly connected to the inlet heater hose <NUM> at inlet port <NUM> and the outlet passage <NUM> is fluidly connected to inlet heater hose <NUM> at outlet port <NUM>.

Inlet heater hose <NUM> fluidly connects inlet passage <NUM> and outlet passage <NUM> of the two-port hydrodynamic heater <NUM> to the vehicle cooling system <NUM> and inlet port <NUM> of heat exchanger <NUM>. Outlet port <NUM> of heat exchanger <NUM> may be fluidly connected to vehicle cooling system <NUM> and water pump <NUM> through exit heater hose <NUM>. Vehicle water pump <NUM> may be used to supply pressurized cooling fluid <NUM> to the two-port hydrodynamic heater <NUM> to maintain the fluid level within the two-port hydrodynamic heater <NUM> at desired level.

Activating the two-port hydrodynamic heater <NUM> (i.e., causing rotor <NUM> to rotate relative to stator <NUM>) causes pressurized cooling fluid <NUM> from water pump <NUM> of vehicle cooling system <NUM> to enter the two-port hydrodynamic heater <NUM> from inlet heater hose <NUM> through inlet passage <NUM>. The cooling fluid <NUM> is heated by the two-port hydrodynamic heater <NUM> in the manner previously described and discharged through outlet passage <NUM> to inlet heater hose <NUM>. The heated cooling fluid <NUM> may be delivered to heat exchanger <NUM> at inlet port <NUM>. Heat from the cooling fluid <NUM> is transferred to airstream <NUM> as the cooling fluid <NUM> passes through the heat exchanger. The cooling fluid <NUM> is discharged from outlet port <NUM> of the heat exchanger <NUM> into exit heater hose <NUM> and returned to the vehicle cooling system <NUM> and water pump <NUM>.

With reference to <FIG>, an alternately configured two-port hydrodynamic heater <NUM> may additionally include an outlet metering device <NUM> fluidly integrated into outlet passage <NUM>. The two-port hydrodynamic heater <NUM> is otherwise configured substantially similar to the two-port hydrodynamic heater <NUM>. Outlet fluid metering device <NUM> operates in conjunction with inlet metering device <NUM> to control the amount of fluid passing through hydrodynamic chamber <NUM>.

Outlet fluid metering device <NUM> may have any of a variety of configurations. For example, outlet fluid metering device <NUM> may include an outlet metering orifice <NUM> having a predetermined configuration based on the design and performance requirements of the particular application. Outlet metering orifice <NUM> may include a generally fixed fluid thru-flow area that remains open to allow a continuous flow of fluid from hydrodynamic chamber <NUM> to outlet port <NUM>. Outlet metering orifice <NUM> may include, for example, an orifice plate or any other device capable of restricting a flow of fluid between hydrodynamic chamber <NUM> and outlet port <NUM>.

The two-port hydrodynamic heater <NUM> may be integrated into a selected application in a similar manner as previously described in connection with the two-port hydrodynamic heater <NUM>. For example, inlet passage <NUM> and outlet passage <NUM> may be fluidly connected to a common external fluid source, such as, for example, inlet heater hose <NUM>. When operating the two-port hydrodynamic heater <NUM>, fluid from the external fluid source (i.e., inlet heater hose <NUM>) enters the two-port hydrodynamic heater <NUM> at inlet port <NUM> and travels sequentially through inlet passage <NUM>, fluid metering device <NUM>, inlet plenum <NUM> and stator supply passage <NUM> to be discharged into hydrodynamic chamber <NUM> through hydrodynamic chamber inlet port <NUM>. Heated fluid discharged from hydrodynamic chamber <NUM> passes through hydrodynamic chamber outlet passage <NUM> to outlet plenum <NUM>. Heated fluid exits outlet plenum <NUM> and passes through outlet metering device <NUM> in outlet passage <NUM> to outlet port <NUM>, where it may be discharged to the external fluid source (i.e., inlet heater hose <NUM>).

Performance of the two-port hydrodynamic heater <NUM> may be at least partially regulated by controlling the flow of fluid being heated in hydrodynamic chamber <NUM> and discharged through outlet port <NUM> of the two-port hydrodynamic heater <NUM>. This may be accomplished by controlling the flow of fluid passing though inlet fluid metering device <NUM> outlet fluid metering device <NUM>. The thru-flow area of inlet metering orifice <NUM> and/or outlet metering orifice <NUM> may be selected to achieve a desired flowrate through hydrodynamic chamber <NUM>. The quantity of fluid passing through hydrodynamic chamber <NUM> may depend in part on the configuration of inlet metering orifice <NUM> and/or outlet metering orifice <NUM> and the pressure drop occurring across the respective fluid metering devices <NUM> and <NUM>.

Referring to <FIG>, a heating system <NUM> includes the two-port hydrodynamic heater <NUM> fluidly connected in parallel with inlet heater hose <NUM>. With this arrangement, a portion of the cooling fluid <NUM> received from cooling system <NUM> passes through the two port hydrodynamic heater <NUM> prior to being delivered to heat exchanger <NUM>. Inlet passage <NUM> of the two-port hydrodynamic heater <NUM> is fluidly connected to the inlet heater hose <NUM> at inlet port <NUM> and the outlet passage is fluidly connected at outlet port <NUM>. Inlet heater hose <NUM> fluidly connects inlet passage <NUM> and outlet passage <NUM> of the two-port hydrodynamic heater <NUM> to the vehicle cooling system <NUM> and inlet port <NUM> of heat exchanger <NUM>. Outlet port <NUM> of heat exchanger <NUM> may be fluidly connected to vehicle cooling system <NUM> and water pump <NUM> through exit heater hose <NUM>. Vehicle water pump <NUM> may be used to supply pressurized cooling fluid <NUM> to the two-port hydrodynamic heater <NUM> to maintain the fluid level within the two-port hydrodynamic heater <NUM> at desired level.

Activating the two-port hydrodynamic heater <NUM> (i.e., causing rotor <NUM> to rotate relative to stator <NUM>) causes pressurized cooling fluid <NUM> from water pump <NUM> of vehicle cooling system <NUM> to enter the two-port hydrodynamic heater <NUM> through inlet passage <NUM> from inlet heater hose <NUM>. The cooling fluid <NUM> is heated by the two-port hydrodynamic heater <NUM> in the manner previously described and discharged through outlet passage <NUM> to inlet heater hose <NUM>. The heated cooling fluid <NUM> may be delivered to heat exchanger <NUM> at inlet port <NUM>. Heat from the cooling fluid <NUM> is transferred to airstream <NUM> as the cooling fluid <NUM> passes through the heat exchanger. The cooling fluid <NUM> is discharged from outlet port <NUM> of the heat exchanger <NUM> into exit heater hose <NUM> and returned to the vehicle cooling system <NUM> and water pump <NUM>.

With reference to <FIG>, an alternately configured two-port hydrodynamic heater <NUM> may include an integrated heat exchanger <NUM> operable for enhancing heat transfer from hydrodynamic chamber <NUM> to a fluid passing through the two-port hydrodynamic heater <NUM>. The two-port hydrodynamic heater <NUM> may be configured and operate substantially the same as the two-port hydrodynamic heater <NUM> with the addition of integrated heat exchanger <NUM>. Heat exchanger <NUM> is fluidly connected in parallel with hydrodynamic chamber <NUM>, such that a portion of fluid entering the two-port hydrodynamic heater <NUM> through inlet port <NUM> bypasses hydrodynamic chamber <NUM> and flows through heat exchanger <NUM>. Fluid discharged from heat exchanger <NUM> combines with fluid discharged from hydrodynamic chamber <NUM> prior to exiting the two-port hydrodynamic heater <NUM> through outlet port <NUM>.

Heat exchanger <NUM> may be positioned within housing <NUM> of the two-port hydrodynamic heater <NUM> adjacent rotor <NUM>. Rotor <NUM> may be located axially along axis of rotation <NUM> between stator <NUM> and heat exchanger <NUM>. A housing wall <NUM> at least partially defines an interior region <NUM> of heat exchanger <NUM> and is positioned between rotor <NUM> and interior region <NUM> of heat exchanger <NUM>.

Heat exchanger <NUM> includes an inlet port <NUM> fluidly connecting the heat exchanger to inlet port <NUM> of the two-port hydrodynamic heater <NUM>, and an outlet port <NUM> fluidly connecting the heat exchanger to outlet port <NUM> of the two-port hydrodynamic heater <NUM>. Heat generated within hydrodynamic chamber <NUM> may pass through rotor <NUM> to fluid present within a cavity <NUM> located between a back surface <NUM> of rotor <NUM> and housing wall <NUM>. In addition, heated fluid discharged from hydrodynamic chamber <NUM> through an opening <NUM> between stator <NUM> and rotor <NUM> may be carried by the fluid to cavity <NUM>. Heat may pass from the fluid present within cavity <NUM> through housing wall <NUM> to heat exchanger <NUM>, where a portion of the heat is transferred to the fluid passing through heat exchanger <NUM>.

A heat transfer effectiveness of heat exchanger <NUM> may be enhanced by employing various geometric surface features to increase a heat transfer surface area of the heat exchanger and the turbulence of the fluid passing through the heat exchanger. For example, the heat transfer surface area of heat exchanger <NUM> may be increased by employing a heat transfer surface extender <NUM>, which operates to increase the available surface area for transferring heat to fluid flowing through heat exchanger <NUM>. Heat transfer surface extender <NUM> may include any of a variety of configurations, including but not limited to, pins, fins and ribs, and may include other surface enhancing configurations designed to enhance heat transfer. The heat transfer surface extenders <NUM> may also operate to increase turbulence of the fluid passing through the heat exchange, which may in turn increase the heat transfer effectiveness of the heat exchanger.

Upon initiating operation of the two-port hydrodynamic heater <NUM> (i.e., causing rotor <NUM> to rotate relative to stator <NUM>), fluid from an external fluid source enters the two-port hydrodynamic heater <NUM> at inlet port <NUM>. The fluid is divided after entering inlet port <NUM>, with a portion entering heat exchanger <NUM> at inlet port <NUM> and the remaining portion flowing to hydrodynamic chamber <NUM> through inlet passage <NUM>. The portion of fluid passing through heat exchanger <NUM> is discharged through outlet port <NUM> and flow to outlet port <NUM> of hydrodynamic heater <NUM>.

Fluid flowing though inlet passage <NUM> passes through inlet metering orifice <NUM> of inlet metering device <NUM> to control the fluid flowrate to hydrodynamic chamber <NUM>. The portion of the fluid directed to hydrodynamic chamber <NUM> is discharged into hydrodynamic chamber <NUM> at hydrodynamic chamber inlet port <NUM>. Heated fluid present within hydrodynamic chamber <NUM> is discharged through hydrodynamic outlet port <NUM> and passed through outlet passage <NUM>. Heated fluid discharged from hydrodynamic chamber <NUM> combines with the heated fluid discharged from heat exchanger <NUM> to be discharged from hydrodynamic heater <NUM> through outlet port <NUM>.

With reference to <FIG>, an alternately configured two-port hydrodynamic heater <NUM> includes the integrated heat exchanger <NUM> operable for enhancing heat transfer from hydrodynamic chamber <NUM> to a fluid passing through the two-port hydrodynamic heater <NUM>. The two-port hydrodynamic heater <NUM> may be configured and operate substantially the same as the two-port hydrodynamic heater <NUM> with the addition of integrated heat exchanger <NUM>. Heat exchanger <NUM> is fluidly connected in parallel with hydrodynamic chamber <NUM>, such that a portion of fluid entering the two-port hydrodynamic heater <NUM> through inlet port <NUM> bypasses hydrodynamic chamber <NUM> and flows through heat exchanger <NUM>. Fluid discharged from heat exchanger <NUM> combines with the fluid discharged from hydrodynamic chamber <NUM> prior to exiting the two-port hydrodynamic heater <NUM> through outlet port <NUM>.

Heat exchanger <NUM> includes inlet port <NUM> fluidly connecting the heat exchanger to inlet port <NUM> of the two-port hydrodynamic heater <NUM>, and outlet port <NUM> fluidly connecting the heat exchanger to outlet port <NUM> of the two-port hydrodynamic heater <NUM>. Heat generated within hydrodynamic chamber <NUM> may pass through rotor <NUM> to fluid present within a cavity <NUM> located between a back surface <NUM> of rotor <NUM> and housing wall <NUM>. In addition, heated fluid discharged from hydrodynamic chamber <NUM> through an opening <NUM> between stator <NUM> and rotor <NUM> may be carried by the fluid to cavity <NUM>. Heat may pass from the fluid present within cavity <NUM> through housing wall <NUM> to heat exchanger <NUM>, where a portion of the heat is transferred to the fluid passing through heat exchanger <NUM>.

Claim 1:
A two port hydrodynamic heater (<NUM>, <NUM>, <NUM>, <NUM>) comprising:
a hydrodynamic heater inlet port (<NUM>) for receiving a stream of fluid from an external source;
a hydrodynamic heater outlet port (<NUM>) operable for discharging a stream of heated fluid from the two port hydrodynamic heater (<NUM>, <NUM>, <NUM>, <NUM>); and
a hydrodynamic chamber (<NUM>) operable to selectively heat a fluid present within an interior region of the hydrodynamic chamber (<NUM>) when operating the two port hydrodynamic heater (<NUM>, <NUM>, <NUM>, <NUM>), the hydrodynamic chamber (<NUM>) including a hydrodynamic chamber inlet port (<NUM>) and a hydrodynamic chamber outlet port (<NUM>) located along an interior wall of the hydrodynamic chamber (<NUM>), the hydrodynamic chamber inlet port (<NUM>) fluidly connected to the hydrodynamic heater inlet port (<NUM>);
the two-port hydrodynamic heater (<NUM>, <NUM>, <NUM>, <NUM>) is operable fluidly connected in parallel with a bypass passage, which fluidly connects the hydrodynamic heater inlet port (<NUM>) to the hydrodynamic heater outlet port (<NUM>),
characterized by
an inlet fluid metering device (<NUM>) having an inlet fluidly connected to the hydrodynamic heater inlet port (<NUM>) and an outlet fluidly connected to the hydrodynamic chamber inlet port (<NUM>);
the inlet fluid metering device (<NUM>) operates to control a flowrate of fluid from the hydrodynamic heater inlet port (<NUM>) to the hydrodynamic chamber (<NUM>).