GB2565998A

GB2565998A - Heat retention apparatus and method

Info

Publication number: GB2565998A
Application number: GB1707315.6A
Authority: GB
Inventors: Richard Hutchins William
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2017-05-08
Filing date: 2017-05-08
Publication date: 2019-03-06
Anticipated expiration: 2037-05-08
Also published as: GB2565998B; GB201707315D0

Abstract

Apparatus for use with an engine 121, comprising an alternator 160 which has an impeller 161 configured to cause air to pass across the alternator. The apparatus comprises thermal insulation 131, configured to encapsulate at least a part of the engine where the alternator is located, and an inlet airflow duct 170, in fluid communication with the alternator and configured to provide a path for cooling air to the alternator. Also claimed is a method for use with such an engine, comprising drawing cooling air to the alternator by the impeller, via such an inlet airflow duct. Preferably, the thermal insulation comprises a thermal shell structure 131 which is spaced apart from the engine to allow airflow there between. Preferably an airflow deflector 147 or a fan 143 is provided to direct air into the thermal shell structure. The inlet airflow duct may extend outside of the thermal insulation, and may extend to a position lower than the alternator or the thermal shell structure. The inlet airflow duct may comprise an outlet portion (172, fig 2) which is aligned with an axis of rotation of the alternator. The outlet portion may have a cross-section which is equal to or greater than the cross section of the alternator.

Description

HEAT RETENTION APPARATUS AND METHOD

FIELD OF THE INVENTION

Aspects of the present invention relate to improvements in the efficiency of vehicle operation. In particular, aspects of the present invention relate to an apparatus, to an engine, to a motor vehicle and to a method.

BACKGROUND

The efficiency of internal combustion engines is known to be dependent at least in part on the viscosity (and therefore the temperature) of the oil used to lubricate the cylinders of the engine. Accordingly, it is desirable for internal combustion engines to be able to attain their normal operating temperature as quickly as possible following a cold start.

It is against this background that the present invention has been conceived. Embodiments of the invention provide a structure, a method or a vehicle which addresses the above problems. Other aims and advantages of the invention will become apparent from the following description, claims and drawings.

SUMMARY OF THE INVENTION

In one aspect of the invention for which protection is sought there is provided an apparatus for use with an engine comprising an alternator having an impeller configured to cause air to pass across the alternator, the apparatus comprising:

thermal insulation configured to encapsulate at least a part of the engine where the alternator is located;

an inlet airflow duct in fluid communication with the alternator, the inlet airflow duct configured to provide a path for cooling air to the alternator.

Optionally, the inlet airflow duct extends to a position which is outside the thermal insulation.

Optionally, the thermal insulation comprises a thermal shell structure configured to at least partially encapsulate the engine, the thermal shell configured to provide thermal insulation, the thermal shell structure configured to be provided in a spaced apart relationship with the engine to allow airflow between the thermal shell structure and the engine.

Optionally, the inlet airflow duct extends to a position which is lower than the alternator.

Optionally, the inlet airflow duct extends to a position which is below a lower edge of the thermal shell structure.

Optionally, the alternator has an axis of rotation, and the inlet airflow duct comprises an outlet portion, wherein the outlet portion is aligned with the axis of rotation.

Optionally, the inlet airflow duct comprises an outlet portion with a cross-sectional area which is equal to, or greater than, a cross-sectional area of the alternator.

Optionally, the inlet airflow duct comprises an outlet portion, and the outlet portion has a fluid-tight seal to the alternator.

Optionally, the apparatus comprises an outlet airflow duct configured to direct outlet air from the alternator.

Optionally, the apparatus comprises an airflow deflector configured to direct air into the thermal shell structure.

Optionally, the apparatus comprises a fan device configured to direct air into the thermal shell structure.

In another aspect of the invention for which protection is sought there is provided a motor vehicle engine provided with an apparatus as disclosed.

In another aspect of the invention for which protection is sought there is provided a motor vehicle comprising an engine and an apparatus as disclosed.

In another aspect of the invention for which protection is sought there is provided a method for use with an engine comprising an alternator having an impeller, comprising:

drawing cooling air to the alternator by the impeller via an inlet airflow duct which is in fluid communication with the alternator, wherein the inlet airflow duct is configured to provide a path for cooling air to the alternator.

It has been found that providing additional thermal insulation around the engine can reduce heat loss, but can reduce the efficiency of an alternator. At least one example of the invention can provide cooling air to the alternator, and therefore prevent overheating of the alternator and/or improve efficiency of the alternator, without the need to provide a flow of cooling air to the entire engine. This can reduce the need to supply energy to a fan or other device to supply cooling air to the overall engine, and can maintain the engine at a higher temperature, thereby reducing the amount of energy required at restart.

Embodiments of the present invention with a thermal shell have the feature that air surrounding the engine within the thermal shell that becomes heated by the engine will remain trapped within the shell unless air is forced upwardly into the thermal shell due to movement of the vehicle or the action of a fan device, as discussed below. However, advantageously, when the engine is switched off and air is no longer being forced upwardly into the thermal shell due to movement of the vehicle, ambient air heated by the engine remains substantially trapped within the volume defined by the shell. It is to be understood that this is due to the greater buoyancy of air warmed by the engine relative to ambient air. Thus embodiments of the present invention have the advantage that circulation of relatively cool, ambient air may take place over the engine block when the engine is in use. Whilst when the engine is switched off, relatively warm ambient air may be trapped between the engine and shell, reducing the rate of cooling of the engine. It is to be understood that, by reducing the rate of cooling of the engine, higher engine start-up temperatures may be enjoyed, depending on the time for which the engine remains switched off. Higher engine startup temperatures reduce losses associated with higher oil viscosity. Higher engine temperatures at start-up may also increase the rate at which an engine after-treatment system warms to its normal operating temperature.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF DRAWINGS

The present 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 a vehicle engine having an apparatus according to an embodiment of the invention;

FIGURE 2 is a schematic illustration of a front view of the vehicle engine and apparatus of the embodiment of FIG. 1 showing an inlet airflow path to the alternator.

DETAILED DESCRIPTION

FIG. 1 is a schematic illustration of a front portion of a vehicle 100 according to an embodiment of the present invention in cross-sectional form as viewed in a transverse direction, i.e. with the vehicle viewed from one side (in the present illustration, a right side). The vehicle 100 has an engine compartment 120 covered by a bonnet (or hood) 103 and separated from a cabin of the vehicle by a cabin bulkhead 102. The engine compartment 120 houses an engine 121 having a head portion (or ‘head’) 121H, a block portion (or ‘block’) 121B and a sump portion (or ‘sump’) 121S. In the embodiment illustrated in FIG. 1 the engine 121 is located between a pair of front wheels 151 of the vehicle 100. An undertray 145 is provided below the engine 121 and spans at least part of a distance between a front bumper 104 and the cabin bulkhead 102. The tray 145 is discontinuous, allowing for flow or air downwardly out from the engine compartment 120.

The engine 121 is provided with an apparatus 130 for promoting engine heat retention having a thermal shell structure 131 substantially in the form of an inverted cup that encloses the head 121H and substantially the entire block 121B of the engine 121. The sump 121S of the engine 121 protrudes below a lower edge of the shell structure 131 in the embodiment shown. In some alternative embodiments the lower edge of the shell structure 131 may be substantially at, or below, a lower level of the sump 121S. In the embodiment of FIG. 1 the thermal shell structure 131 may be said to have an upper, or top, portion and a downwardlydirected skirt portion 132 that projects downwardly from the top portion. The thermal shell structure 131 has an open lower face.

The thermal shell structure 131 may be provided as a single integral piece (e.g. which can be lifted from the engine) or as a plurality of pieces which fit together to provide the thermal shell structure. Examples of suitable materials for the shell structure include cellular foam or matted fibres. The thermal shell structure 131 may comprise layered skins of material or a composite/bonded assembly of materials.

The thermal shell structure 131 may be provided in addition to any insulation lining a periphery of the engine compartment 120. For example, insulation material may be provided on one or more of: an underside of the bonnet 103; the cabin bulkhead 102; sides of the engine compartment 120. Alternatively, the thermal shell structure 131 may be provided instead of any insulation lining a periphery of the engine compartment 120. The thermal shell structure 131 provides thermal insulation at a closer distance to the engine 121 than insulation lining the engine compartment. The thermal shell structure 131 provides a more effective way of reducing heat loss from the engine 121.

The vehicle 100 has a radiator pack 140 provided within the engine compartment 120 behind a front grille 105 of the vehicle 100. The front grille 105 optionally has active grill shutters 105S that are pivotable between an open condition and a closed condition. In the open condition the active grill shutters 105S permit a flow of ram air into the engine compartment 120 when the vehicle 100 travels in a forward direction. In the closed condition the active grill shutters 105S block a flow of ram air into the engine compartment 120 when the vehicle 100 travels in a forward direction. The active grill shutters 105S are caused to switch between the open and closed conditions by means of an actuator device under the control of a controller 100C in a known manner.

The radiator pack 140 has a fan device (or blower) 143 arranged to draw air through a radiator 141 and the front grille 105 when the active grill shutters 105S are open. The fan device 143 blows the air rearwardly towards the thermal shell structure 131. In the present embodiment the fan device 143 is electrically powered although in some embodiments the device 143 may be engine driven.

Some of the air blown rearwardly by the fan device 143 is deflected downwardly by the thermal shell structure 131. A device is provided to deflect, or to guide, or to scoop, a portion of the air flowing rearwardly through the engine compartment 120. FIG. 1 shows a deflector 147. This may be called an air velocity deflector 147. The air velocity deflector 147 directs the air under the lower edge 133 of the skirt portion of the thermal shell structure 131 and upwardly between the engine 121 and thermal shell structure 131. Air drawn through the front grille 105 is thus introduced into the thermal shell structure 131 and forced in an upward direction between the engine block 121B and the thermal shell structure 131. Existing air within the thermal shell structure 131 is therefore displaced, being ultimately forced downwardly out from the thermal shell structure 131 and exhausted from the engine compartment 120.

The air velocity deflector 147 may be open or closed at the sides. In some alternative embodiments the deflector 147 may be in the form of an open air-deflecting surface arranged to direct air from the front of the vehicle 100 upwardly into the thermal shell structure 131. The deflector 147 may be referred to as a scoop in some embodiments. In some embodiments an air velocity deflector 147 may not be provided.

In FIG. 1 air flow lines are shown, illustrating the flow of air passing through the radiator grill 105, the radiator pack 140, the air velocity deflector 147 and within the thermal shell structure 131.

It is to be understood that, in the present embodiment, the flow rate of air through the deflector 147 and up within the thermal shell structure 131 may be controlled at least in part by means of the active grill shutters 105S of the front grille 105 (open or closed) and the state of the fan device 143 (on or off).

In the present embodiment, controller 100C is provided for controlling the state of the fan device (switching it on or off) and the state of the active grill shutters 105S (causing them to open and close). The controller 100C monitors the temperature of the engine 121 by means of a temperature sensor 101. When the temperature exceeds a first predetermined temperature the controller 100C causes the active grill shutters 105S to open. For example, the first predetermined temperature can be in the range from around 80-90 °C. If the temperature exceeds a second predetermined temperature the controller 100C causes the fan device 143 to switch on in addition to maintaining the active grill shutters 105S in the open condition.

It is to be understood that, in use, the engine 121 and thermal shell structure 131, which is fixedly coupled to the engine 121, experience movement within the engine bay 120 such as a rocking movement during acceleration and deceleration. Whilst in some embodiments the air velocity deflector 147 could be coupled to the radiator pack 140 to increase the flow of air through the deflector 147, the fact that the engine 121, thermal shell structure and air velocity deflector 147 are decoupled from the radiator pack 140 in the present embodiment eliminates problems associated with direct coupling such as wear. In the present embodiment the air velocity deflector 147 is positioned such that a flow of air is maintained therethrough from the radiator pack 140, when the blower device is running, even at the extremes of movement of the engine 121 within the engine bay 120 in normal use.

In the embodiment of FIG. 1, engine sump 121S protrudes below the thermal shell structure 131 and is exposed to air flowing between the undertray 145 and thermal shell structure 131.

In the embodiment shown, the sump 121S is provided with close-coupled thermal insulation thereover in the form of a sprayed-on foam insulation layer. Other forms of thermal insulation may be useful such as sheet-form insulation bonded to the sump by means of an adhesive, or attached thereto by means of mechanical fixing elements such as screws, bolts, clips or the like. In some embodiments thermal insulation is not provided in contact with the sump 121S.

In some embodiments, one or more fan devices may be provided for directing air into the thermal shell structure 131 substantially directly and not via the radiator pack 140. Optionally, the one or more fan devices may be connected to the thermal shell structure 131 or to the deflector 147.

The engine 121 has an alternator 160. The alternator 160 provides a function of converting mechanical energy of the engine into electrical energy. An electrical output of the alternator 160 can charge a battery (not shown) on the vehicle. The alternator 160 has an impeller (fan) 161, shown in FIG. 2. The impeller 161 provides a flow of air across (i.e. through and/or around) the alternator when the alternator is driven. For example, the impeller 161 may be mounted on an axial shaft of the alternator 160. The flow of air cools the alternator and prevents components such as electrical windings and/or electrical components (e.g. diodes) from overheating.

FIG. 2 shows a front view of the engine and thermal shell structure, with more detail of the alternator 160 and the inlet airflow duct 170. The alternator 160 may be driven by a drive belt 163 coupled between a pulley 162 on the alternator 160 and a pulley 164 on a drive shaft of the engine 121. It will be understood that this drawing shows one possible example of driving the alternator. Other ways of driving the alternator are possible. FIG.2 shows an impeller 161 located between the pulley 162 and a main body of the alternator which houses electrical windings (and electrical components) of the alternator. In other types of alternator, the impeller 161 may be located internally of a housing of the alternator. An inlet airflow duct 170 is provided. The inlet airflow duct 170 is in fluid communication with the alternator 160. The inlet airflow duct 170 is configured to provide a path for cooling air to the alternator 160. Therefore, the impeller 161 can draw cool air to the alternator, even when the vehicle is stationary and/or the main fan device 143 is turned off.

In this embodiment the inlet airflow duct 170 extends for a distance 175 below the lower edge 133 of the thermal shell structure 131. The lower edge 133 of the thermal shell structure is taken as the skirt of the thermal shell structure, not including any deflector or scoop 147. An example, non-limiting, value for distance 175 is up to 50mm. Generally, the region below the lower edge 133 of the thermal shell structure 131 is likely to be cooler than the region within the thermal shell structure. More generally, the inlet airflow duct 170 may extend to a position which is lower than the alternator 160. In some embodiments the inlet airflow duct 170 may extend to a position which is substantially at the same level as the lower edge 133 of the thermal shell structure 131. In some embodiments the inlet airflow duct 170 may extend to a position which is above the lower edge 133 of the thermal shell structure 131. For example, if there is a flow path of cooling air within the thermal shell structure 131, the inlet flow duct 170 may extend to the flow path, without extending beneath the lower edge of the thermal shell structure 131.

The inlet airflow duct 170 comprises an outlet portion 172 nearest to the alternator 160. In the embodiment shown in FIG. 2 the alternator is mounted on the engine 121 with an axis of rotation 165 aligned horizontally. The outlet portion 172 is configured to direct airflow horizontally towards the alternator 160. The outlet portion 172 has a cross-sectional area which is substantially the same as a cross-sectional area of the alternator 160. More generally, the outlet portion 172 can have a cross-section which is equal to, or greater than, a diameter of the alternator 160. The outlet portion 172 may have a fluid-tight seal to the alternator 160.

In the embodiment shown in FIG. 2 the inlet airflow duct 170 comprises a first portion 171 which is vertically oriented and an outlet portion 172 in the form of an elbow which receives airflow from the first portion and directs airflow horizontally towards the alternator 160. It will be understood that the inlet airflow duct 170 may have a different shape. For example, the first portion 171 of the inlet airflow duct 170 may be diagonal rather than vertical, or may have a non-linear shape.

In the embodiment shown in FIG. 2 the inlet flow duct 170 is fluidly connected to a first axial end of the alternator 160 which is opposite to a second axial end of the alternator where the pulley 162 and the drive belt 163 are located.

After air has passed across the alternator 160, the air passes through outlet apertures on the second axial end of the alternator 160. The outlet air may disperse within the volume under the thermal shell structure 131. In an embodiment (not shown) the alternator 160 may be provided with an outlet airflow duct. The outlet airflow duct is in fluid communication with the alternator 160. The outlet airflow duct can be directed to improve airflow through the thermal shell structure 131. In an embodiment, the outlet airflow duct can be directed towards a portion of the engine 120 which is shielded from air flow between the thermal shell 131 and the engine 120. In an embodiment, the outlet airflow duct can be directed towards a component of the engine 120 with a high operating temperature.

In some embodiments, one or more baffles or other wall-like structures may be provided for controlling the direction of flow of air between the engine 121 and the thermal shell structure 131.

It is to be understood that a thermal shell structure 131 according to an embodiment of the invention may itself have a lower edge 133 that is any suitable depth (distance) below the top of the engine block 121B such as 50%, 75%, 80, 90%, 100%, 110%, 120% or any other suitable depth.

In the embodiment shown in FIG. 1 and FIG. 2 a thermal shell structure 131 is provided to encapsulate the engine 121. In another embodiment (not shown) thermal insulation may be provided around a part of the engine 121 where the alternator 160 is located, but the thermal insulation does not encapsulate the entire engine. The inlet flow duct 170 provides a flow of cooling air to the alternator from a position which is outside the thermal insulation.

It will be understood that the embodiments described above are given by way of example only and are not intended to limit the invention, the scope of which is defined in the appended claims.

Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of the words, for example “comprising” and “comprises”, means “including but not limited to”, and is not intended to (and does not) exclude other moieties, additives, components, integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

Claims

CLAIMS:

1. Apparatus for use with an engine comprising an alternator having an impeller configured to cause air to pass across the alternator, the apparatus comprising:

2. An apparatus according to claim 1 wherein the inlet airflow duct extends to a position which is outside the thermal insulation.

3. An apparatus according to claim 1 or 2 wherein the thermal insulation comprises a thermal shell structure configured to at least partially encapsulate the engine, the thermal shell configured to provide thermal insulation, the thermal shell structure configured to be provided in a spaced apart relationship with the engine to allow airflow between the thermal shell structure and the engine.

4. An apparatus according to claim 3 wherein the inlet airflow duct extends to a position which is lower than the alternator.

5. An apparatus according to claim 3 or 4 wherein the inlet airflow duct extends to a position which is below a lower edge of the thermal shell structure.

6. An apparatus according to any one of the preceding claims wherein the alternator has an axis of rotation, and the inlet airflow duct comprises an outlet portion, wherein the outlet portion is aligned with the axis of rotation.

7. An apparatus according to any one of the preceding claims wherein the inlet airflow duct comprises an outlet portion with a cross-sectional area which is equal to, or greater than, a cross-sectional area of the alternator.

8. An apparatus according to any one of the preceding claims wherein the inlet airflow duct comprises an outlet portion, and the outlet portion has a fluid-tight seal to the alternator.

9. An apparatus according to any one of the preceding claims comprising an outlet airflow duct configured to direct outlet air from the alternator.

10. An apparatus according to any one of the preceding claims comprising an airflow deflector configured to direct air into the thermal shell structure.

5

11. An apparatus according to claim 3, or any claim dependent on claim 3, comprising a fan device configured to direct air into the thermal shell structure.

12. A motor vehicle engine provided with an apparatus according to any one of the preceding claims.

13. A motor vehicle comprising an engine and an apparatus according to any one of claims 1 to 11.

14. A method for use with an engine comprising an alternator having an impeller,

15 comprising: