SYSTEM AND METHOD FOR HEAT REMOVAL FROM CONFINED SPACES IN A MOTOR VEHICLE USING NATURAL ASPIRATION AND CURIE TEMPERATURE

Abstract

A system (30) and method for removing heat from a confined space such as from engine compartment or service brake of a motor vehicle where heat is generated by operation of a heat engine (12) that propels the vehicle or application of a friction brake. The system and method do not use engine or electrical power because natural aspiration is used to remove heated air and Curie Temperature of a ferromagnetic material is used to selectively allow and disallow natural aspiration.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a representative motor vehicle to which principles of the invention are applied.

FIG. 2 is schematic diagram of a first embodiment illustrating principles of the invention.

FIG. 2A is a longitudinal cross section view through an example of a device that incorporates certain functions performed in accordance with principles of the invention.

FIG. 3 is schematic diagram of a second embodiment.

FIG. 4 is a diagram showing application of certain inventive principles to a portion of the vehicle shown in FIG. 1.

FIG. 5 is a diagram similar to FIG. 4 showing a different application.

FIG. 6 is a diagram showing application of certain inventive principles to another portion of the vehicle shown in FIG. 1.

FIG. 7 is a diagram similar to FIG. 6 showing a different application.

FIG. 8 is a generic representation of a preferred form for one sub-system of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a truck 10 having an internal combustion engine 12, a diesel engine for example, and a drivetrain 14 that couples engine 12 to driven rear wheels 16R for propelling the truck. Engine 12 is housed within an engine compartment 18 that is forward of a cab 20.

Engine 12 is liquid-cooled, with the engine cooling system comprising a radiator 22 disposed generally vertical at the front of engine compartment 18 behind a grille opening. A fan 24 behind radiator 22 can draw air through radiator 22 to aid in cooling engine coolant flowing through radiator 22 when needed.

Engine 12 also has an exhaust system 26 for conveying exhaust gases generated by combustion of fuel in cylinders of engine 12 from the engine to the ambient atmosphere surrounding truck 10.

For reasons that were mentioned earlier, engine heat may create temperatures within engine compartment 18 that are higher than desired. Consequently, a heat removal system that can remove some engine compartment heat may be helpful in avoiding undesirably high engine compartment temperatures.

A first embodiment of inventive heat removal system 30 is shown in FIG. 2 to comprise a collection sub-system 32 for collecting heat in engine compartment 18, a conveyance sub-system 34 for conveying heat from collection sub-system 32 to an exhaust manifold of exhaust system 26, and a sensor sub-system 36 for allowing and disallowing conveyance of heat collected by collection sub-system 32 through conveyance sub-system 34 to exhaust system 26 based on temperature in engine compartment 18.

Exhaust system 26 serves as an exit sub-system that is open to ambient atmosphere. When engine 12 is running, the exhaust flow applies a partial vacuum to the outlet of conveyance sub-system 34 by an effect similar to that performed by an ejector or eductor. When sensor sub-system 36 allows conveyance of engine compartment heat by opening collection sub-system 32 to conveyance sub-system 34, the partial vacuum creates natural aspiration of air carrying engine compartment heat from collection sub-system 32 through conveyance sub-system 34 and the exit sub-system to ambient atmosphere thereby removing heat from the engine compartment to ambient atmosphere. The use of natural aspiration for heat removal avoids power draw from engine 12 or the electrical system of truck 10.

For opening and closing collection sub-system 32 to conveyance sub-system 34, sensor sub-system 36 utilizes the Curie Temperature of a ferromagnetic material, enabling heat removal to be controlled without drawing energy from the engine or the electrical system.

A ferromagnetic part senses engine compartment temperature. A magnet and the ferromagnetic part are organized and arranged such that when the temperature of the ferromagnetic part does not exceed the Curie Temperature, the magnetic force exerted by the magnet on the ferromagnetic part relatively positions them to close collection sub-system 32 to conveyance system 34, disallowing the natural aspiration of heated air out of the engine compartment. When the temperature of the ferromagnetic part equals or exceeds the Curie Temperature, the loss of ferromagnetism in the part allows the part and magnet to assume relative positions that open collection sub-system 32 to conveyance system 34, disallowing natural aspiration.

The operating position of an obturator for allowing and disallowing natural aspiration is established by the relative positions of the ferromagnetic part and the magnet. When the part and magnet assume relative positions that allow natural aspiration, the obturator opens collection sub-system 32 to conveyance system 34. When the part and magnet assume relative positions that disallow natural aspiration, the obturator closes collection sub-system 32 to conveyance system 34.

FIG. 2A shows an example where the obturator, a sphere 31, is unseated from a magnet 33 above a certain temperature to allow flow indicated by arrow 35. Attribution for this example is given to Invention Machine Corporation.

Collection sub-system 32 is embodied by way of example as a walled body having an interior void and an entrance to that void through which the void is open to air in engine compartment 18. By making the walled body approximate a “black body” as that term is understood in physics, it becomes an approximate ideal absorber of radiant heat. This allows the body wall to collect heat radiated from engine 12 and to re-radiate the heat to the interior void. Heat is also transferred by conduction to air that is in contact with the interior wall surface of the void.

FIG. 5 shows a “control valve” (understood to comprise the magnet, the ferromagnetic part, and the obturator), as sensor sub-system 36. The collection sub-system 32 comprises a walled black body having an entrance at an end opposite the end where the “control valve” is associated. The conveyance sub-system tees into exhaust system 26 to provide the exit to ambient atmosphere for both engine exhaust and removed engine compartment heat.

FIG. 3 shows principles of the invention being applied to removal of heat from the service brakes of truck 10. Both rear wheels 16R and front wheels 16F have friction brake mechanisms that when operated by a brake pedal inside cab 20 to brake the truck generate heat. In the case of a drum-type brake the heat is generated within a confined space. Placement of a sensor sub-system 36 and a collection sub-system 32 in association with a friction brake can remove some of the brake heat, with the removed heat being removed to atmosphere as in FIG. 2.

FIGS. 6 and 7 show a sensor sub-system 36 and a collection sub-system 32 in association with a friction brake. The sensor sub-system is understood to comprise the magnet, the ferromagnetic part, and the obturator, collectively named “control valve” in both Figures. The collection sub-system comprises a walled black body having an entrance at an end opposite the end where the sensor sub-system is associated.

Although not specifically shown by FIGS. 6 and 7, a preferred geometry for the body of collection sub-system has a narrowing taper in the direction of natural aspiration flow, as shown generically by FIG. 8.

The exit sub-system of FIG. 7 is the same as in FIGS. 2 and 3. The exit sub-system of FIG. 6 is somewhat different. The outlet of the exit system is open to ambient atmosphere and is arranged in relation the direction of air flow along the truck when the truck is moving such that partial vacuum is created at the outlet.

FIG. 4 shows an embodiment like FIG. 5 insofar as sub-systems 32, 34, and 36 are concerned. The exit system of FIG. 5 is like the one in FIG. 7.

With the ability of the inventive system to selectively allow and disallow removal of heat from an engine compartment, it may be possible to incorporate the system into the design of an engine compartment in a way that makes obstruction of the radiator in winter, such as by covering, unnecessary.

While a presently preferred embodiment of the invention has been illustrated and described, it should be appreciated that principles of the invention apply to all embodiments falling within the scope of the following claims.

Claims

1. A self-propelled vehicle comprising: wheels on which the vehicle travels, at least some of which wheels are driven to self-propel the vehicle when the vehicle is being operated;a heat removal system for removing heat from a confined space containing a device that generates heat when the vehicle is being operated;the heat removal system comprising a collection sub-system for collecting heat in the confined space, a conveyance sub-system for conveying heat from the collection sub-system to an exit sub-system, and a sensor sub-system for allowing and disallowing conveyance of heat collected by the collection sub-system through the conveyance sub-system to the exit sub-system based on temperature in the confined space;wherein the exit sub-system is open to ambient atmosphere and is constructed and arranged to apply to the conveyance sub-system a partial vacuum that is created as a result of the vehicle being operated, and when the sensor sub-system allows conveyance of heat, the partial vacuum creates natural aspiration of air carrying heat from the collection sub-system through the conveyance sub-system and the exit sub-system to ambient atmosphere thereby removing heat from the confined space to ambient atmosphere.

2. A vehicle as set forth in claim 1 wherein the confined space containing the device comprises an engine compartment containing a heat engine, and wherein the heat engine drives the driven wheels through a drivetrain.

3. A vehicle as set forth in claim 1 wherein the device comprises a friction brake that is associated with a wheel and that when operated while the wheel is turning, slows the wheel by frictional force that converts kinetic energy in the wheel into heat within the confined space.

4. A vehicle as set forth in claim 1 wherein the sensor sub-system comprises a ferromagnetic part characterized by a Curie Temperature defining the lower limit of a temperature range that causes the part to lose ferromagnetism when heated to a temperature within the range, and the ferromagnetic part functions to allow the natural aspiration when the part's temperature is within the range and to disallow the natural aspiration when the part's temperature is not within the range.

5. A vehicle as set forth in claim 4 wherein the sensor sub-system further comprises a magnet, and the ferromagnetic part and the magnet are organized and arranged such that when the temperature of the ferromagnetic part is not within the range, the magnetic force exerted by the magnet on the ferromagnetic part relatively positions them to disallow the natural aspiration, and when temperature of the ferromagnetic part is within the range, the loss of ferromagnetism in the part allows the part and magnet to assume relative positions that allow the natural aspiration.

6. A vehicle as set forth in claim 1 wherein the sensor sub-system comprises an obturator arranged to selectively allow the conveyance sub-system to be open to the collection sub-system and disallow the conveyance sub-system from being open to the collection sub-system.

7. A vehicle as set forth in claim 1 wherein the collection sub-system comprises a body having an interior void, an entrance to the void from the confined space, and an outlet from the void to the conveyance sub-system.

8. A vehicle as set forth in claim 7 wherein the body is constructed to have a black body characteristic approximating a perfect absorber of thermal radiation.

9. A vehicle as set forth in claim 1 wherein the exit sub-system comprises an exhaust system for conveying exhaust flow from the engine to ambient atmosphere, and the conveyance sub-system is constructed and arranged to introduce the natural aspiration of the air carrying heat into the exhaust system for entrainment with the exhaust flow.

10. A vehicle as set forth in claim 1 wherein the exit sub-system comprises an outlet open to ambient atmosphere and arranged in relation the direction of air flow along the vehicle when the vehicle is being propelled to cause partial vacuum to be created at the exit sub-system outlet.

11. A method for removing heat from a confined space in a self-propelled vehicle, which space contains a device that generates heat when the vehicle is being operated, the method comprising: collecting heat in the confined space;on the basis of temperature in the confined space, selectively allowing and disallowing conveyance of collected heat to an exit that is open to ambient atmosphere; andoperating the vehicle to create a partial vacuum at the exit that causes conveyance of heat by natural aspiration of air carrying heat from the confined space to the exit when conveyance of heat is allowed.

12. A method as set forth in claim 11 wherein the step of collecting heat in the confined space comprises collecting heat in an engine compartment containing a heat engine that propels the vehicle.

13. A method as set forth in claim 11 wherein the step of collecting heat in the confined space comprises collecting heat created by operation of a friction brake that is associated with a wheel of the vehicle.

14. A method as set forth in claim 11 wherein the step of selectively allowing and disallowing conveyance of collected heat to an exit comprises using the Curie Temperature of a ferromagnetic part that senses temperature in the confined space to demarcate allowing conveyance of collected heat from disallowing conveyance of collected heat.

15. A method as set forth in claim 14 wherein the step of selectively allowing and disallowing conveyance of collected heat to an exit comprises exerting magnetic force on the ferromagnetic part.

16. A method as set forth in claim 11 wherein the step of selectively allowing and disallowing conveyance of collected heat to an exit comprises selectively positioning an obturator in a flow path through which the natural aspiration occurs for selectively allowing and disallowing the natural aspiration.

17. A method as set forth in claim 11 wherein the step of collecting heat in the confined space comprises collecting heat in a body that has an interior void, an entrance to the void from the confined space, and an outlet from the void to the exit.

18. A method as set forth in claim 17 wherein the step of collecting heat in the body comprises collecting radiant heat by constructing the body to have a black body characteristic approximating a perfect absorber of thermal radiation.

19. A method as set forth in claim 11 wherein the step of operating the vehicle to create a partial vacuum at the exit comprises operating a heat engine that propels the vehicle, conveying exhaust flow from the engine to ambient atmosphere, and entraining the heat conveyed by natural aspiration with the exhaust flow.

20. A method as set forth in claim 11 wherein the step of operating the vehicle to create a partial vacuum at the exit comprises disposing an outlet of the exit in ambient atmosphere and arranging the outlet in relation the direction of air flow along the vehicle such that when the vehicle is being propelled, partial vacuum is created at the outlet.

21. A system for selectively removing heat from an engine compartment of a self-propelled vehicle containing a heat engine that operates to propel the vehicle when the vehicle is being operated and in the process generates heat in the engine compartment, the system comprising: a collection sub-system disposed in the engine compartment, an exit sub-system leading to ambient atmosphere, a conveyance sub-system from the collection sub-system to the exit sub-system, and a sensor sub-system for allowing and disallowing the system to remove heat;wherein the exit sub-system is open to ambient atmosphere and is constructed and arranged to apply to the conveyance sub-system a partial vacuum that is created as a result of the vehicle being operated, and when the sensor sub-system allows removal of heat, the partial vacuum creates natural aspiration of air carrying heat from the engine compartment through the collection, conveyance, and exit sub-systems to ambient atmosphere, and when the sensor sub-system disallows removal of heat, natural aspiration through the collection, conveyance, and exit sub-systems to ambient atmosphere is stopped.

22. A system as set forth in claim 21 wherein the sensor sub-system comprises a ferromagnetic part characterized by a Curie Temperature defining the lower limit of a temperature range that causes the part to lose ferromagnetism when heated to a temperature within the range, and the ferromagnetic part causes the sensor sub-system to be effective to open the collection, conveyance, and exit sub-systems for natural aspiration when the part's temperature is within the range and to stop natural aspiration through the collection, conveyance, and exit sub-systems when the part's temperature is not within the range.

23. A system as set forth in claim 21 wherein the exit sub-system comprises an exhaust system for conveying exhaust flow from the engine to ambient atmosphere, and the conveyance sub-system is constructed and arranged to introduce the air carrying heat from the engine compartment into the exhaust system for entrainment with the exhaust flow.