Patent Description:
Environmental control systems (ECS) are utilized on various types of aircraft for several purposes, such as in cooling systems for the aircraft. For example, components of the ECS may be utilized to remove heat from various aircraft lubrication and electrical systems and/or used to condition aircraft cabin air. The cabin air conditioner includes one or more cabin air compressors (CACs) which compress air entering the system, from an outside source or from a ram air system. The compressed air is delivered to an environmental control system to bring it to a desired temperature, and then the compressed air is delivered to the aircraft cabin. After passing through the cabin, the air is typically exhausted to the outside. The CACs are typically driven by air-cooled electric motors, which are cooled by a flow of cooling air typically drawn by the ram air system. Conditions of the CAC, such as heating of the components therein during use, are controlled to extend a useful life of the CACs.

<CIT> discloses a cabin air compressor with a cooling jacket.

<CIT> discloses a flexible cooling jacket positioned around an electric motor and conforming to the case of the motor.

Disclosed is a compressor as defined by claim <NUM> for use as a cabin air compressor (CAC) of an aircraft environmental control system.

In embodiments, an inlet port and an outlet port of the cooling jacket are fluidly coupled via at least one internal passage or bladder within the cooling jacket.

In addition, the cooling jacket may at least partially include insulating material.

The cooling jacket may be configured to cool a motor, a forward motor support bearing, and an aft motor support bearing of the compressor.

The cooling jacket may at least partially include a first passage through which a motor air cooling inlet channel of the CAC extends; the cooling jacket may at least partially include a defines a second passage through which a bearing air cooling inlet channel of the CAC extends; and the cooling jacket may at least partially include a third passage through which a cooling outlet channel of the CAC extends.

Aforward end of the supplemental cooling jacket may be configured to be removably attached to a flange of the CAC.

In embodiments, an inlet portion of the CAC extends aft of the forward end to a diffuser portion of the CAC; the diffuser portion extends aft of the inlet portion to a compressor rotor portion of the CAC; the compressor rotor portion extends aft of the diffuser portion to a forward bearing portion of the CAC; the forward bearing portion extends aft of the compressor rotor portion to a motor portion of the CAC; the motor portion extends aft of the forward bearing portion to an aft bearing portion of the CAC; and the aft bearing portion extends aft of the motor portion to the aft end of the CAC; wherein the cooling jacket extends over the aft bearing portion, the motor portion and the forward bearing portion of the CAC.

In embodiments, the cooling jacket terminates at the forward bearing portion of the CAC, adjacent the compressor rotor portion.

In embodiments, a forward journal bearing of the forward bearing portion is rotationally supported between a forward stationary member of the CAC case and a forward motor shaft operationally connected to the motor; an aft journal bearing of the aft bearing portion is rotationally supported between an aft stationary member of the CAC case and an aft motor shaft operationally connected to the motor.

In embodiments, a thrust bearing of the aft bearing portion is rotationally supported between the aft end of the CAC case and the aft motor shaft.

An aircraft is disclosed including an environmental control system, which includes a compressor having any of the above aspects.

<FIG> illustrates an example of a commercial aircraft <NUM> having aircraft engines surrounded by (or otherwise carried in) a nacelle <NUM> housing therein a gas turbine engine. The aircraft <NUM> includes two wings <NUM> that can each include one or more slats <NUM> and one or more flaps <NUM>. The aircraft may further include ailerons <NUM>, spoilers <NUM>, horizontal stabilizer trim tabs <NUM>, horizontal stabilizer <NUM> and rudder <NUM>, and vertical stabilizer <NUM> (the tail structure being collectively referred to as an and empennage) each of which may be typically referred to as "control surfaces" as they are movable under aircraft power systems. The aircraft <NUM> may include an environmental control system (ECS) <NUM>, illustrated schematically, which conditions air that is delivered to the passenger cabin <NUM> of the aircraft <NUM>. The ECS <NUM> may receive compressed air from a cabin air compressor (CAC) <NUM>, as indicated above.

The components of a CAC <NUM> are shown in <FIG> and includes a CAC case <NUM> extending from a case forward end <NUM> to a case aft end <NUM>, where the case aft end <NUM> is spaced apart from the case forward end <NUM> in an axial aft direction <NUM>. An inlet portion <NUM> (otherwise referred to as a compressor inlet portion), shown schematically, is defined by the CAC <NUM>, aft of the case forward end <NUM>. The inlet portion <NUM> extends in the axial aft direction <NUM> from the case forward end <NUM> to an add heat portion <NUM> of the CAC <NUM>. The inlet portion <NUM> of the CAC <NUM> receives, for example, air from outside the aircraft, e.g., from a ram air system of the aircraft <NUM>.

The add heat portion <NUM> is defined by the CAC <NUM>, aft of the inlet portion <NUM>. The add heat portion <NUM> extends in the axial aft direction <NUM> from the inlet portion <NUM> to a compressor rotor portion <NUM> of the CAC <NUM>.

The compressor rotor portion <NUM> is defined by the CAC <NUM>, aft of the add heat portion <NUM>. The compressor rotor portion <NUM> extends axially aft from the add heat portion <NUM> to a forward bearing portion <NUM>. A compressor rotor <NUM> is housed within the compressor rotor portion <NUM>. The compressor rotor <NUM> rotates about a compressor drive rod <NUM> (or center drive rod) that extends in the axial aft direction <NUM> from the compressor rotor <NUM>, toward the case aft end <NUM>, and rotates about a rotation axis <NUM> (or center rotation axis).

The forward bearing portion <NUM> is defined by the CAC <NUM>, aft of the compressor rotor portion <NUM>. The forward bearing portion <NUM> extends in the axial aft direction <NUM> from the compressor rotor portion <NUM> to a motor portion <NUM>. The compressor drive rod <NUM> extends axially through the forward bearing portion <NUM> of the CAC <NUM>. A forward motor shaft <NUM> within the forward bearing portion <NUM> supports the compressor drive rod <NUM> via a forward drive rod support <NUM> that extends in the radial outer direction <NUM> between the forward motor shaft <NUM> and compressor drive rod <NUM>. A forward journal bearing <NUM> (or forward motor support bearing) within the forward bearing portion <NUM> is rotationally positioned between a forward case structure <NUM> (or stationary member) and the forward motor shaft <NUM>.

The motor portion <NUM> of the CAC <NUM> is defined by the CAC <NUM>, aft of the forward bearing portion <NUM>. The motor portion <NUM> extends in the axial aft direction <NUM>, from the forward bearing portion <NUM> to an aft bearing portion <NUM>. A motor <NUM>, including a motor stator <NUM> and a motor rotor <NUM>, is housed within the motor portion <NUM>. The motor stator <NUM> is radially exterior to and axially aligned with the motor rotor <NUM>. The compressor drive rod <NUM> extends axially through the motor portion <NUM> of the CAC <NUM> and is operationally connected to the motor rotor <NUM>, e.g., to drive the compressor rotor <NUM>.

The aft bearing portion <NUM> of the CAC <NUM> is defined by the CAC <NUM>, aft of the motor portion <NUM>. The aft bearing portion <NUM> extends in the axial aft direction <NUM>, from the motor portion <NUM> to the case aft end <NUM> of the CAC case <NUM>. The compressor drive rod <NUM> extends the axial aft direction <NUM>, into the aft bearing portion <NUM> of the CAC <NUM>. An aft motor shaft <NUM> (or thrust shaft) extends in the axial aft direction <NUM> from the motor rotor <NUM> to a thrust plate <NUM> at the case aft end <NUM> of the CAC case <NUM>. The aft motor shaft <NUM> supports the compressor drive rod <NUM> via an aft drive rod support <NUM> that extends in the radial outer direction <NUM> between the aft motor shaft <NUM> and compressor drive rod <NUM>. An aft journal bearing <NUM> is within the aft bearing portion <NUM>, rotationally supported between the aft motor shaft <NUM> and an aft support structure <NUM> (another stationary member) of the CAC case <NUM>, thereby supporting the compressor drive rod <NUM>. A thrust bearing <NUM> engages the thrust plate <NUM> at the aft end of the CAC case <NUM>. The aft journal bearing <NUM> and thrust bearing <NUM> may together be considered aft motor support bearings.

Turning to <FIG>, a bearing cooling circuit <NUM> is defined in the CAC <NUM> for directing a bearing cooling flow <NUM> of air through the CAC <NUM>. The cooling air may also be from a primary heat exchanger of the aircraft or may be from a different source. The bearing cooling circuit <NUM> includes a bearing cooling inlet channel <NUM>, formed as an inlet passage in the aft bearing portion <NUM> of the CAC case <NUM>. A cooling outlet channel <NUM> is formed as an outlet passage in the forward bearing portion <NUM> of the CAC case <NUM>. The CAC <NUM> is configured so that bearing cooling flow <NUM> is directed around the thrust bearing <NUM>, over the aft journal bearing <NUM>, between the compressor drive rod <NUM> and the motor rotor <NUM>, over the forward journal bearing <NUM>, and out of the cooling outlet channel <NUM>. From there, the air may be directed overboard or utilized for other purposes. The bearing cooling inlet channel <NUM> may extend along a bearing cooling inlet channel axis <NUM> that is normal to the rotation axis <NUM> for the compressor rotor <NUM>. This configuration is not intended on limiting an orientation of the bearing cooling inlet channel <NUM>.

A motor cooling circuit <NUM> is defined in the CAC <NUM> for directing a motor cooling flow <NUM> of air through the CAC <NUM>. The motor cooling circuit <NUM> includes a motor cooling inlet channel <NUM> formed in the aft bearing portion <NUM> of the CAC <NUM>. The motor cooling inlet channel <NUM> receives the motor cooling flow <NUM> via a motor cooling duct <NUM> connected to a bleed channel <NUM> that is tapped off of the inlet portion <NUM> of the CAC <NUM>. The CAC <NUM> is configured so that motor cooling flow <NUM> is directed between the motor rotor <NUM> and motor stator <NUM>, between the motor stator <NUM> and the CAC case <NUM>, and out of the cooling outlet channel <NUM>. The motor cooling inlet channel <NUM> may extend along a motor cooling inlet channel axis <NUM> that is normal to the rotational axis for the compressor rotor <NUM>, and e.g., parallel to bearing cooling inlet channel axis <NUM>. This configuration is not intended on limiting an orientation of the bearing cooling inlet channel <NUM>.

CAC motor reliability is dependent on the motor and bearings operating efficiently, meaning at least in part that the components are prevented from overheating. The CAC motor, as indicated above is cooled at least partially by cooling airflows, which under certain conditions may be insufficient to provide the desired cooling levels to the motor components. This may have a direct impact on system performance.

In view of the above concerns, as shown in <FIG> and <FIG>, the CAC <NUM> includes a supplemental cooling jacket <NUM> (the jacket). The jacket <NUM> is formed of a synthetic fabric, positioned around the CAC case <NUM> and conforms to the shape of the CAC case <NUM>. The jacket <NUM> is configured to direct a supplemental cooling medium <NUM> through it. In one embodiment the supplemental cooling medium <NUM> is a liquid.

The jacket <NUM> includes an inlet port <NUM> (<FIG> and <FIG>) and an outlet port <NUM> (<FIG> and <FIG>), fluidly coupled via at least one internal passage or bladder <NUM> within the jacket <NUM>. The inlet and the outlet ports <NUM>, <NUM> may respectively include quick release adaptors <NUM>, <NUM>, to respectively connect with inlet and outlet conduits <NUM>, <NUM>. Further, the jacket <NUM> is at least partially filled with insulating material <NUM>.

The jacket <NUM> is disposed around portions of the CAC case <NUM> that house the motor <NUM> and forward and aft journal bearings <NUM>, <NUM>. That is, the jacket <NUM> extends over the aft bearing portion <NUM>, the motor portion <NUM> and the forward bearing portion <NUM> of the CAC <NUM>. The jacket <NUM> terminates at the forward bearing portion <NUM> of the CAC <NUM>, adjacent the compressor rotor portion <NUM>. With this configuration, the forward bearing portion <NUM>, the motor portion <NUM> and the aft bearing portion <NUM>, and moving components therein, are configured to be cooled by the jacket <NUM>.

For example, a primary heat removal circuit of the disclosed embodiments includes heat being removed from the motor portion <NUM>, including the motor <NUM> therein, and the forward and aft bearing portions <NUM>, <NUM>, the bearings therein, including the forward and aft journal bearings <NUM>, <NUM>, and the thrust bearing <NUM>, via convection by the motor cooling flow <NUM>, and then by the motor cooling flow <NUM> being cooled by convection against the case <NUM>. In turn, the case <NUM> conducts heat to the jacket <NUM>, and the jacket <NUM> removes heat by convection via fluid flowing in the jacket <NUM>.

From the compressor rotor portion <NUM> to the forward case end <NUM>, the CAC <NUM> is not covered by the jacket <NUM> (<FIG> and <FIG>). In some embodiments, the jacket <NUM> may be sized and configured to cover more or less of the CAC case <NUM>, such as, for example, covering only the motor portion <NUM>. In some embodiments, more than one jacket <NUM> is utilized, where each jacket covers one or more portions of the CAC case <NUM>.

The jacket <NUM> may define a first passage or aperture <NUM> through which the motor air cooling inlet channel <NUM> (<FIG> and <FIG>) of the CAC <NUM> extends. The jacket <NUM> may further define a second passage or aperture <NUM> through which the bearing cooling inlet channel <NUM> of the CAC <NUM> extends. The jacket <NUM> may further define a third passage or aperture <NUM> through which the cooling outlet channel <NUM> of the CAC <NUM> extends. A forward end <NUM> of the jacket <NUM> may be removably attached to a flange <NUM> or other case mounting structure <NUM> of the CAC <NUM>, to enable removal as needed.

Utilizing the above disclosed jacket <NUM> as an additional source of cooling, e.g., by cooling the CAC <NUM> around the motor <NUM>, may greatly reduce motor stator and bearing temperatures, so that the stator motor operates more reliably and has a longer useful life. It is within the scope of the disclosure to utilize existing liquid cooling loops in an aircraft <NUM> to provide the liquid cooling flow to the CAC <NUM> to increase CAC reliability.

Claim 1:
A compressor suitable to be used as a cabin air compressor (CAC) of an aircraft environmental control system, the compressor comprising:
a compressor case (<NUM>) defining a forward end (<NUM>), an aft end (<NUM>) axially spaced apart from the forward end, wherein the forward end defines a compressor inlet (<NUM>); and
a cooling jacket (<NUM>),
wherein the cooling jacket is configured to direct a cooling medium (<NUM>) through it;
characterised in that
the cooling jacket is a supplemental cooling jacket positioned around at least a portion of the compressor case and at least partially conforming the compressor case, and in that the supplemental cooling jacket (<NUM>) is formed from a synthetic fabric.