Patent Description:
In existing vehicles, oil is commonly used to cool electronic components, such as a motor and generator. A cooler is typically arranged within the fluid loop to remove heat from the oil. However, coolers requires a significant amount of space onboard the vehicle, as well as a system for moving air through the cooler <CIT> relates to an engine cooling system.

In an embodiment the secondary fluid is provided from a source external to the vehicle.

The secondary fluid may be air driven by the propulsion system.

The secondary fluid may be an airflow generated by movement of the vehicle.

In an embodiment the secondary fluid is provided from a source located onboard the vehicle.

In an embodiment the portion of the cooling system further comprises a heat exchanger, the heat exchanger being configured to receive the cooling fluid and the secondary fluid.

The heat exchanger may be a tube-fin heat exchanger having a base and a plurality of fins extending outwardly from the base.

The cooling fluid may be configured to move through the base and the secondary fluid may be configured to pass between the plurality of fins.

In an embodiment the portion of the cooling system further comprises a conduit, wherein the cooling fluid is configured to flow through the conduit away from the electric component.

In an embodiment the portion of the cooling system further comprises a conduit, wherein the cooling fluid is configured to flow through the conduit to the electric component.

In an embodiment the at least one propulsion system includes a first propulsion system and a second propulsion system, the first propulsion system being arranged at a first end of the strut and the second propulsion system being arranged at a second end of the strut.

In an embodiment the at least one propulsion system is arranged at a first end of the strut and the body is arranged at a second end of the strut.

A method of cooling an electric component of a vehicle is defined in claim <NUM>.

In an embodiment arranging the cooling fluid in the heat exchange relationship with the secondary fluid further comprises passing a flow of the secondary fluid about the strut.

Arranging the cooling fluid in the heat exchange relationship with the secondary fluid may further comprise providing a flow of the secondary fluid from a source located external to the vehicle.

In an embodiment the secondary fluid is air driven by the propulsion system.

In an embodiment arranging the cooling fluid in the heat exchange relationship with the secondary fluid further comprises providing a flow of the secondary fluid from on board the vehicle.

With reference now to <FIG>, an example of a vehicle <NUM>, such as a vertical take-off and landing rotary wing aircraft for example, is illustrated. As shown, the vehicle <NUM> includes a body or fuselage <NUM> having a generally aerodynamic shape and including a nose section <NUM>, a trailing end or tail section <NUM> opposite from the nose section <NUM>, and an airframe <NUM>. The vehicle additionally includes at least one propulsion system <NUM> mounted to the fuselage <NUM>. In the illustrated, non-limiting embodiment, the vehicle <NUM> has a plurality of rotor propulsion systems <NUM> mounted at each opposing side of the fuselage; however, it should be understood that a vehicle <NUM> having any number of rotor propulsion systems <NUM> including a single rotor propulsion system, and/or a single rotor propulsion system mounted at each side of the fuselage is within the scope of the disclosure.

In an embodiment, best shown in <FIG>, the rotor propulsion systems <NUM> are mounted to the fuselage <NUM> in groups, for example pairs, with each pair including a first rotor propulsion 30a system arranged adjacent to a first side of the fuselage <NUM> and a second rotor propulsion system 30b arranged adjacent to a second, opposite side of the fuselage <NUM>. In such embodiments, the first and second rotor propulsion system 30a, 30b within a pair may be substantially identical such that the rotor propulsion systems 30a, 30b are capable of balancing forces therebetween. In embodiments where the vehicle <NUM> includes multiple groups or pairs of rotor propulsion systems, each of the rotor propulsion systems mounted at the same side of the aircraft, such as systems identified by 30a or 30b for example, may have similar, or alternatively, may have different configurations.

With continued reference to <FIG> and further reference to <FIG>, in an embodiment, the vehicle <NUM> may include at least one rotor propulsion system operable during a first flight mode, indicated at L1-L8, such as during take-off or landing for example, and at least one rotor propulsion system, identified at C1-C2, operable during a second mode of operation, such as during cruise for example. Accordingly, the size and/or configuration of at least a portion of a rotor propulsion system 30a, 30b associated with the first flight mode may be different than the size and/or configuration of at least a portion of a rotor propulsion system 30a, 30b associated with the second flight mode.

Each rotor propulsion system <NUM> is mounted to a portion of the fuselage <NUM>, such as to the airframe <NUM> for example, via a structural component or strut <NUM>. In embodiments where the rotor propulsion systems 30a, 30b are arranged in pairs, a pair of rotor propulsion systems 30a, 30b may be mounted to the fuselage <NUM> via a single strut <NUM>. For example, the first rotor propulsion system 30a may be mounted at a first end <NUM> of the strut <NUM> and the second rotor propulsion system 30b may be mounted at the second end <NUM> of the strut <NUM>. However, embodiments where each rotor propulsion system <NUM> is mounted to a separate strut <NUM> are also contemplated herein.

In an embodiment, best shown in <FIG>, each rotor propulsion system <NUM> includes a rotor <NUM> having a plurality of rotor blades <NUM> mounted to a rotor hub <NUM>. A rotor shaft <NUM> extending from the rotor hub <NUM> may be driven about an axis of rotation X via an electric component, such as an electric motor, illustrated schematically at <NUM>. Each rotor <NUM> may be driven by a separate motor <NUM>, or alternatively, a plurality of rotors <NUM> may be driven by a single motor <NUM>. The one or more electric motors <NUM> may be controlled by a controller CONT in response to a flight control system (not shown).

Although the vehicle <NUM> is described herein as having rotor propulsion systems <NUM> that include an electric motor <NUM>, it should be understood that embodiments where the vehicle <NUM> is a hybrid vehicle and therefore additionally includes a gas turbine engine operably coupled to the one or more rotors <NUM> are also within the scope of the disclosure. Further, it should be appreciated that other configurations of an aircraft including fixed-wing aircraft, tiltrotor aircraft, rotary-wing aircraft, and tail-sitting VTOL aircraft, and other vehicles having an electrically powered rotor propulsion system may also benefit from embodiments disclosed.

During operation, one or more electric components of the vehicle <NUM>, such as the motors <NUM> used to drive the rotor propulsion systems <NUM> for example, typically generate heat. A cooling system <NUM> including a cooling fluid C is therefore used to remove heat from the electrical components to maintain the electrical components at a suitable temperature. With continued reference to <FIG>, the cooling system <NUM> associated with a motor <NUM> of a rotor propulsion system is at least partially embedded within the interior of the strut <NUM> supporting the motor <NUM> and the corresponding rotor <NUM> of the rotor propulsion system <NUM>. For example, at least one conduit fluidly connected to the motor <NUM> is arranged within the strut <NUM>. The at least one conduit may include one or more conduits <NUM> configured to move the heated cooling fluid away from the motor <NUM> and/or one or more conduits <NUM> for delivering a cool temperature cooling fluid to the motor <NUM>.

Heat is configured to be removed from the cooling fluid while the cooling fluid C is arranged within the interior of the strut <NUM>. The cooling fluid within the interior of the strut <NUM> is cooled via a heat exchange relationship with a secondary fluid. The secondary fluid may be another fluid provided from a source located onboard the vehicle <NUM>, such as fuel for example, or may be provided from a source external to the vehicle <NUM>. An airflow, such as the fresh or outside air A moved by the rotor <NUM> of the rotor propulsion system <NUM> and/or generated by movement of the vehicle <NUM> may be used as the secondary fluid to cool the cooling fluid. In an embodiment, the secondary fluid is configured to flow about an exterior of the strut <NUM> to cool the cooling fluid C. The secondary fluid is configured to flow through the interior of the strut <NUM>. In such embodiments, as best shown in <FIG>, one or more scoops <NUM> formed at an exterior of the strut <NUM> may provide an inlet to the interior of the strut <NUM>.

In an embodiment, a heat exchanger <NUM> is arranged within the interior of the strut <NUM> along the fluid flow path of the cooling fluid C. As shown in <FIG>, the heat exchanger <NUM> may be arranged directly upstream from the motor relative to flow of the cooling fluid C. In such embodiments, as a flow of heated cooling fluid moves through the conduit <NUM> towards the motor <NUM>, heat is transferred to the secondary fluid. Accordingly, by the time that the cooling fluid C reaches the motor <NUM>, the cooling fluid C has been cooled to a suitable temperature to remove heat from the motor <NUM>. In other embodiments, best shown in <FIG>, the heat exchanger <NUM> may be arranged downstream from the electric motor <NUM> relative to the flow of the cooling fluid C such that the cooling fluid C is cooled generally directly downstream from the outlet of the motor <NUM>.

An example of a heat exchanger <NUM> positionable within the interior of a strut <NUM> is illustrated in <FIG> and <FIG>. In the illustrated, non-limiting embodiment, the heat exchanger <NUM> is a tube-fin heat exchanger having a generally cylindrical base <NUM> configured to receive the heated cooling fluid C. The conduit containing the heated cooling fluid C may be mounted concentrically within the interior <NUM> of the base <NUM>, or in an embodiment, the hollow interior of the base <NUM> may define a portion of the conduit. As shown, a plurality of fins <NUM> extends generally radially outwardly from the base <NUM>. The fins <NUM> may extend over the entire length (between a first end and a second opposite end) of the base, or may extend over only a portion of the length thereof. Each of the plurality of fins <NUM> is spaced apart from another of the plurality of fins <NUM>.

In one embodiment, the heat exchanger <NUM> is substantially axisymmetric about its longitudinal axis L. The plurality of fins <NUM> may, but need not be, substantially identical. In addition, the size and/or shape of each of the plurality of fins <NUM> may be generally constant over its length. Alternatively, the size and/or shape of at least one of the plurality of fins <NUM> may vary about the periphery of the base <NUM> or over the length of the base <NUM>. In the illustrated, non-limiting embodiment, one or more of the plurality of fins <NUM> has a constant thickness, but a non-linear contour. For example, as shown, all or at least a portion of the fins <NUM> has one or more waves extending along the longitudinal axis L of the heat exchanger <NUM>. It should be understood that the heat exchanger illustrated and described herein is intended as an example only and that any suitable type of heat exchanger, such as a double pipe, shell and tube, plate, plate and shell, adiabatic shell, plate fin, pillow plate, and fluid heat exchanger is within the scope of the disclosure.

The vehicle <NUM> may have a separate cooling system <NUM> associated with each of the plurality of rotor propulsion systems <NUM> and/or electrical components. However, in an embodiment, a single cooling system <NUM> may be operably coupled to a plurality of rotor propulsion systems <NUM>. With reference to <FIG>, in the illustrated, non-limiting embodiment, the cooling system <NUM> is a closed loop system configured to cool each of the rotor propulsion systems <NUM>. As shown, the cooling system <NUM> includes a tank <NUM> containing a volume of cooling fluid C. A pump <NUM> is configured to deliver cooling fluid from the tank <NUM> to one or more delivery conduits <NUM>. Each of the plurality of conduits <NUM> is fluidly connected to a main conduit <NUM> such that the cooling fluid C may be delivered to the conduits <NUM> in parallel. A valve, not shown, may be arranged within the conduit <NUM> or at the interface between the main conduit <NUM> and a respective conduit <NUM>. In such embodiments, the valve may be operable to selectively control a flow of cooling fluid C to the motor <NUM> of the rotor propulsion system <NUM> associated with the conduit <NUM>, such as based on an operational state of the motor <NUM> for example. The heated flow of cooling fluid C output from the motor <NUM> is then cooled within the strut <NUM> as it passes through the conduit <NUM> to a second main conduit <NUM> configured to return the cooling fluid C to the tank <NUM>.

Other electrical components of the vehicle <NUM>, such as a generator for example, may also be cooled by the cooling system <NUM>. In the illustrated, non-limiting embodiment, a first portion of the cooling fluid C output from the tank <NUM> may be directed towards a generator <NUM> while the second portion is provided to the main conduit <NUM> for delivery to the rotor propulsion systems <NUM>. The cooling fluid output from the generator <NUM> may then be provided directly to the tank <NUM>, or alternatively, may be cooled, such as via a heat exchanger for example, before being returned to the tank <NUM>. In addition, cooling fluid C from the pump <NUM> can also be directed to one or more motor controllers to cool them (not shown).

By integrating the cooling of the cooling fluid C into the cooling system <NUM>, the need for separate cooling components, such as nacelle fans for example can be eliminated. Accordingly, a vehicle having a cooling system <NUM> as described herein may have a reduced sizing envelope, weight, and energy consumption.

Claim 1:
A vehicle (<NUM>) comprising:
a body (<NUM>);
at least one propulsion system (<NUM>) including an electric component, wherein the electric component is a motor operable to drive the propulsion system (<NUM>);
a strut (<NUM>) extending between the body (<NUM>) and the at least one propulsion system (<NUM>); and
a cooling system (<NUM>) operably coupled to the electric component of the at least one propulsion system (<NUM>), wherein a portion of the cooling system is arranged within the strut (<NUM>), wherein the cooling system (<NUM>) includes a cooling fluid, characterized in that heat is removed from the cooling fluid within the portion of the cooling system by a secondary fluid and wherein the cooling fluid is in a heat exchange relationship with the secondary fluid, and wherein a flow of the secondary fluid is delivered, in use, to an interior of the strut.