GB2385307A

GB2385307A - Vehicle air-conditioning compressor drive arrangement

Info

Publication number: GB2385307A
Application number: GB0203772A
Authority: GB
Inventors: Yong Hock Lawrence Sim
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-02-18
Filing date: 2002-02-18
Publication date: 2003-08-20
Anticipated expiration: 2022-02-18
Also published as: GB2385307B; GB0203772D0

Abstract

In a vehicle having an air-conditioning compressor 1 this can be driven by the vehicle engine 2 or, when the engine is stopped, by an electric motor 6. A drive pulley 10 includes a ratchet clutch (Fig. 3) to disconnect the electric motor 6 from the compressor when the engine is running. The electric motor may be coaxial with the compressor instead of connected through a belt drive (Fig. 1b). The electric motor 6 may be supplied from a dedicated battery 7 instead of the main vehicle battery.

Description

DUAL-DRIVE (AUTOMOTIVE AIR-CONDITIONING) COMPRESSOR The present invention relates to a compressor driver apparatus.

Many automotive vehicles are provided with air-conditioning systems which are based upon compressors. In conventional arrangements a compressor is powered by a vehicle engine. Power generated by the engine is transferred to the compressor by a belt which connects a crankshaft pulley to a pulley provided on a rotor shaft of the compressor. When the engine is running the crankshaft pulley is rotated, thereby driving the belt which in turn rotates the compressor pulley and compressor rotor shaft.

The known arrangement of compressor driver apparatus suffers from the disadvantage that the compressor is only driven when the engine is running. If it is desired to operate the compressor when the vehicle is stationary, then the engine must be turned on. This is disadvantageous for several reasons. The design of the vehicle engine is designed to power the vehicle, and as such is not an efficient means of powering the compressor. Using the vehicle engine in this way thus represents an expensive waste of fuel for the vehicle user. In addition, running the vehicle engine when stationary unnecessarily adds pollution to the environment by way of exhaust fumes from the engine. Some of the exhaust fumes are harmful, for example carbon monoxide, and in some circumstances may pose a danger to the vehicle user. In the case of an electric-powered vehicle, using the vehicle's electric motor to power the compressor is inefficient since the motor is designed to power the vehicle rather than the compressor. Operating the compressor when the vehicle is stationary will thus cause a considerable drain of power stored in the vehicle's battery.

It is an object of the present invention to provide a compressor drive apparatus which overcomes at least one of the above disadvantages.

According to the invention there is provided a compressor drive apparatus comprising a first power transfer means arranged to transfer power from a vehicle

engine to a compressor rotor, and a second power transfer means arranged to transfer power from an electric motor to the compressor rotor, wherein the power transfer means are provided with engagement means arranged to allow the second power transfer means to engage and drive the compressor rotor when the vehicle engine is not operating.

The invention is advantageous because it allows efficient operation of the compressor when the vehicle engine is not running.

Preferably, the engagement means is arranged to allow only one of the power transfer means to engage and drive the compressor rotor at any given time.

Preferably, both the first and the second power transfer means are arranged to drive the compressor rotor to rotate in one same direction.

Preferably, the first power transfer apparatus comprises a disk fixed to a shaft of the compressor rotor and an annulus provided around an outer perimeter of the disk, the engagement means being arranged to allow the annulus to engage and drive the disk when rotating in one direction, and to disengage from the disk, when the disk is rotated in the same direction by the second power source.

Preferably, the second power transfer apparatus comprises a disk fixed to a shaft of the compressor rotor and an annulus provided around an outer perimeter of the disk, the engagement means being arranged to allow the annulus to engage and drive the disk when rotating in one direction, and to disengage from the disk, when the disk is rotated in the same direction by the first power source.

Preferably, the engagement means comprises a leaf-spring held in the disk and partially protruding from the disk, together with a recess provided in the annulus, the recess being configured to engage with the leaf-spring when the rotational relationship between the annulus and the disk is in one same direction, and to slide over the leaf-spring when the rotational relationship is in the opposite direction.

Alternatively, the engagement means comprises a leaf-spring located in the annulus and partially protruding from the annulus, together with a recess provided in the disk, the recess being configured to engage the leaf-spring when the rotational relationship between the annulus and the disk is in one same direction, and to slide over the leaf-spring when the rotational relationship is in the opposite direction.

Preferably, power from the electric motor is delivered to the second power transfer means by a belt which passes around the second annulus and to the electric motor.

Preferably, the electric motor has an axis of rotation which corresponds to the axis of rotation of the rotor shaft, and power from the electric motor is delivered directly to the second annulus.

Preferably, power from the vehicle engine is delivered to the first power transfer means by a belt which passes around the first annulus to a crankshaft of the vehicle engine.

Preferably, a third annulus is provided at the outermost surface of the first annulus, the first and third annuluses together connected via a magnetic clutch.

Preferably, the electric motor is driven by an auxiliary battery. The term auxiliary battery is intended to mean that the battery is not the main battery of the vehicle.

Preferably, the battery is rechargeable, and may be recharged via an alternator when the vehicle engine is operating.

Specific embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is a schematic illustration of two embodiments of the invention,

Figure 2 is a side view of disk and annulus arrangements which comprise part of the embodiments of the invention; Figure 3 is a plan view one of the disk and annulus arrangements shown in figure 2; Figure 4 is a perspective view of an exterior casing of one embodiment of the invention; Figure 5 is a perspective view of an exterior casing of a second embodiment of the invention; and Figure 6 is a perspective view of a belt and pulley system of a vehicle engine which includes an embodiment of the invention.

Figure la shows schematically a first embodiment of the invention which comprises a compressor 1 and engine 2. Power is transferred from the engine 2 to the compressor 1 via a crank shaft pulley 3, a belt 4 and a compressor pulley 5 (referred to hereafter as an engine driven compressor pulley 5). This part of the invention corresponds to a conventional prior art arrangement. However, in addition to the conventional arrangement an electric motor 6 powered by a battery 7 is also provided. The electric motor 6 is connected via an electric motor pulley 8 and second belt 9 to a second compressor pulley 10 (referred to hereafter as an electric motor driven compressor pulley 10). During conventional operation the electric motor 6 is not activated, and the compressor 1 is driven by the engine 2. When the engine 2 is

turned off, the compressor 1 is driven by the electric motor 6.

Figure 1 b shows a second embodiment of the invention. In this embodiment power is transferred from an engine 2 to a compressor 1 via a crank shaft pulley 3, a belt 4 and an engine driven compressor pulley 5. In addition, an electric motor 11 is built around the axis of rotation of a rotor shaft of the compressor 1. The electric motor 11 is powered by a battery 7. During conventional operation the electric motor 11 is not activated, and the compressor 1 is driven by the engine 2. When the engine 2 is turned off the compressor 1 is driven by the electric motor 11.

Figure 2 shows in more detail the pulleys 5,10 of the first embodiment of the invention. The electric motor driven compressor pulley 10 comprises a disk 12 fixed to a rotor shaft 13 of the compressor. An annulus 14 is provided around the outer perimeter of the disk 12. The disk 12 is arranged to slide over the annulus 14 without engaging the annulus 14 when driven in a clockwise direction by pulley 5. The annulus 14 is arranged to engage and drive the disk 12 when driven in a clockwise direction (clockwise and is defined when looking along the rotor shaft 13 in the direction of arrow A). The annulus 14 is driven by the belt 9.

The engine driven compressor pulley 5 comprises a disk 15 which is fixed to the rotor shaft 13. An annulus 16 is provided around the perimeter of the disk 15.

The disk 15 is arranged to slide over the annulus 16 without engaging the annulus 16 when driven in a clockwise direction by pulley 10. The annulus 16 is arranged to engage and drive the disk 15 when driven in a clockwise direction. A third annulus 17 is provided around the perimeter of the first annulus 16. This annulus is known as a rotating rim, and is arranged to magnetically engage or disengage the first annulus 16 through the action of a magnetic clutch system. This allows the compressor to be disengaged from the engine when required. The operation and construction of magnetic clutch systems is well known in the art.

Figure 3 shows a side view of the electric motor driven compressor pulley 10.

The pulley 10 comprises the inner disk 12 fixed to the compressor rotor shaft 13, and the annulus 14. A housing 18 is cut into the disk 12, and a leaf-spring 19 is held within the housing 18. Part of the leaf-spring 19 projects from the housing 18 and resiliently presses against an innermost surface of the annulus 14. The annulus 14 is provided with an angled groove 20. The angled groove 20 is arranged so that when the disk 12 rotates in a clockwise direction, the leaf-spring 19 slides over the groove 20 without engaging the groove 20. The leaf-spring 19 may move slightly into the angled groove 20, but will then exit the groove 20 by following the taper of the groove 20. A narrow gap 21 is provided between the disk 12 and the annulus to accommodate the leaf-spring 19 as the disk 12 rotates.

The angled groove 20 is arranged so that when the annulus 14 rotates in a clockwise direction the leaf-spring 19 will expand into the groove 20 and will be engaged therein. The disk 12 and rotor shaft 13 are thereby driven to rotate in the clockwise direction.

Referring to figure 2, the engine driven compressor pulley 5 is configured in the same way as the electric motor driven compressor pulley 10, the leaf-spring and angled groove (not shown in figure 2) are oriented in the same direction so that the compressor's rotor shaft 13 is driven by the engine when the annulus 16 rotates in a clockwise direction. As previously mentioned, rotation of the annulus 16 may be turned on and off using the rotating rim magnetic clutch system.

It will be appreciated that it is important that the engine and the electric motor are not configured so that they both attempt to rotate the compressor's rotor shaft 13 at the same time.

It will be appreciated that the disks 12,15 attached to the compressor rotor shaft 13 will rotate whenever the compressor rotor shaft 13 rotates. Whichever of the disks 12,15 is passively rotating will slide within its respective annulus 14,16.

Referring to figure 1, the apparatus is operated according to a strict logic such that the electric motor 6,11 is turned on only when the engine 2 is not running. This means that the electric motor driven compressor pulley 10 and the engine driven compressor pulley 5 are never both driven simultaneously. If for some reason both compressor pulleys 5,10 are driven simultaneously this will not cause failure of the apparatus or damage to the apparatus. Instead, the compressor rotor shaft 13 will be driven by whichever pulley is rotating at a higher speed.

Under no circumstances can power be transferred from one compressor pulley 5 to the other compressor pulley 10. This means that the engine cannot inadvertently drive the electric motor or vice versa.

The second embodiment of the invention corresponds to the embodiment described in relation to figure 2 and figure 3, with the difference that there is no belt 9 as the annulus 14 is driven directly by the electric motor 11.

Figure 4 shows the exterior of a compressor pulley driven by an electric motor spaced away from the compressor pulley (i. e. the first embodiment of the invention).

Figure 5 shows the exterior of a compressor pulley driven by an electric motor located around the axis of the compressor rotor (i. e. the second embodiment of the invention) Figure 6 shows a typical arrangement of a vehicle belt and pulley system incorporating the first embodiment of the invention. A battery 7 powers an electric motor which in turn powers a compressor pulley located within a housing 22. A belt 4 passes over an engine crankshaft pulley 3 and an engine driven compressor pulley 5.

In addition the belt 4 passes over an air pump pulley 23, an alternator pulley 24, an idler pulley 25, a power steering pulley 26 and a water pump pulley 27. It can be seen from figure 6 that the configuration of the embodiment of the invention is sufficiently compact and simple that it may be fitted to a vehicle engine in a similar manner as a convention compressor driver apparatus, without significantly affecting the engine or the vehicle's belt and pulley system.

The battery 7 is rechargeable, and is recharged by the engine by means of an alternator when the engine is running. The battery 7 is an auxiliary battery, and is provided in addition to the conventionally provided main vehicle battery (not shown).

The invention is particularly advantageous when used in conjunction with vehicles powered by non-conventional sources, for example electric vehicles, hybridengine vehicles, fuel cell powered vehicles, etc. This is because the battery will power the compressor in a much more efficient manner than the main engine of such vehicles, thereby avoiding wasting power (power consumption is a primary limitation of such vehicles)

Claims

CLAIMS 1. A compressor drive apparatus comprising a first power transfer means arranged to transfer power from a vehicle engine to a compressor rotor, and a second power transfer means arranged to transfer power from an electric motor to the compressor rotor, wherein the power transfer means are provided with engagement means arranged to allow the second power transfer means to engage and drive the compressor rotor when the vehicle engine is not operating.
2. An apparatus according to claim 1, wherein the engagement means is arranged to allow only one of the power transfer means to engage and drive the compressor rotor at any given time.
3. An apparatus according to claim 1 or claim 2, wherein both the first and the second power transfer means are arranged to drive the compressor rotor to rotate in one same direction.
4. An apparatus according to claim 3, wherein the first power transfer apparatus comprises a disk fixed to a shaft of the compressor rotor and an annulus provided around an outer perimeter of the disk, the engagement means being arranged to allow the annulus to engage and drive the disk when rotating in one direction, and to disengage from the disk when the disk is rotated by the second power transfer apparatus in the same direction.
5. An apparatus according to claim 3, wherein the second power transfer apparatus comprises a disk fixed to a shaft of the compressor rotor and an annulus provided around an outer perimeter of the disk, the engagement means being arranged to allow the annulus to engage and drive the disk when rotating in one direction, and to disengage from the disk when the disk is rotated by the first power transfer apparatus in the same direction.

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6. An apparatus according to claim 4 or claim 5, wherein the engagement means comprises a leaf-spring held in the disk and partially protruding from the disk, together with a recess provided in the annulus, the recess being configured to engage with the leaf-spring when the rotational relationship between the annulus and the disk is in one same direction, and to slide over the leaf-spring when the rotational relationship is in the opposite direction.
7. An apparatus according to claim 4 or claim 5, wherein the engagement means comprises a leaf-spring located in the annulus and partially protruding from the annulus, together with a recess provided in the disk, the recess being configured to engage the leaf-spring when the rotational relationship between the annulus and the disk is in one same direction, and to slide over the leaf-spring when the rotational relationship is in the opposite direction.
8. An apparatus according to claim 5, wherein power from the electric motor is delivered to the second power transfer means by a belt which passes around the second annulus and to the electric motor.
9. An apparatus according to claim 5, wherein the electric motor has an axis of rotation which corresponds to the axis of rotation of the rotor shaft, and power from the electric motor is delivered directly to the second annulus.
10. An apparatus according to claim 4, wherein power from the vehicle engine is delivered to the first power transfer means by a belt which passes around the first annulus to a crankshaft of the vehicle engine.
11. An apparatus according to claim 10, wherein a third annulus is provided at the outermost surface of the first annulus, the first and third annuluses together connected via a magnetic clutch.
12. An apparatus according to any preceding claim, wherein the electric motor is driven by an auxiliary battery.

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13. An apparatus according to claim 12, wherein the battery is rechargeable, and may be recharged via an alternator when the vehicle engine is operating.
14. A compressor drive apparatus substantially as hereinbefore described with reference to the accompanying figures.