WO1998044255A1

WO1998044255A1 - Turbocharger integral fluid temperature management system

Info

Publication number: WO1998044255A1
Application number: PCT/US1998/005690
Authority: WO
Inventors: Kevin E. Stay; Lee Wilson
Original assignee: Alliedsignal Inc.
Priority date: 1997-03-31
Filing date: 1998-03-24
Publication date: 1998-10-08
Also published as: AU6769598A

Abstract

A fluid thermal management system includes a heat exchanger (20) mounted to receive inlet air to a turbocharger compressor (12) as a thermal exchange medium to cool a working fluid. The heat exchanger has a tubular extension (22) mounted to the inlet (14) of the turbocharger compressor, a conduit (24) for the working fluid, mounted for thermal contact of the fluid with an exterior surface of the extension, and a plurality of fins (26) mounted in thermal contact with an interior surface of the extension and extending radially inwardly for heat transfer to the inlet air. Fluid heating is accomplished by employing a second heat exchanger (40), of substantially identical configuration of the first heat exchanger, mounted to receive outlet air from the turbocharger compressor as a thermal exchange medium to heat the working fluid. For both heat exchangers, a bypass valve (62) mounted in the fluid line is controllable for directing fluid flow into the heat exchanger.

Description

TURBOCHARGER INTEGRAL FLUID TEMPERATURE MANAGEMENT

SYSTEM

CROSS REFERENCE TO RELATED APPLICATIONS This application claims the benefit of the filing date of provisional application

60/042,559 having a filing date of March 31, 1997 entitled Turbocharger Integral Fluid Temperature Management System

BACKGROUND OF THE INVENTION Field of the Invention;

The present invention relates generally to the field of fluids thermal management in internal combustion engine powered vehicles. More particularly, the invention provides a fluid flow path control system integrated with a turbocharger and employing the inlet and outlet airflow from the compressor as a heat exchange medium with cooling fins internal to heat exchangers integrally mounted on the compressor inlet and outlet, the fins further providing aerodynamic benefit in directing flow into or out of the compressor. Description of the Related Art:

The development of internal combustion engines with higher power requirements, high density packaging of the engine and subsystems in very constrained vehicle under-hood configurations, and the addition of subsystems with cumulative heating or cooling needs has increased the demands on thermal control capability. The thermal demands of some engine fluids, most notably in diesel engines the fuel temperature requirements in various high and low temperature operating environments, have not been adequately addressed.

In modern diesel engines, especially those used in class 6, 7 and 8 heavy trucks, high pressure fuel injection systems are employed to improve combustion efficiency. This high pressure, in combination with the fuel coming in contact with the hot injectors, causes the fuel heating. The injectors only use 10 - 15% of the fuel that is provided by the fuel pump. The remaining 85 - 90% of the fuel is returned back to the tank at a lower pressure, but still at an elevated temperature. This parasitic heating creates operating difficulties for the engine when tank temperature or fuel temperature increases beyond approximately 150°F. Various operating problems occur with the fuel and its combustion efficiency when this temperature is reached. Conventional cooling systems have not been effectively employed to solve this fuel heating problem. Mounting of an air-to-fuel cooler in the front of the vehicle or in the main cooling air stream is not satisfactory due to the possibility of vibration, thermal cycling or front-end collisions causing leaks to occur resulting in fuel in the engine compartment and spillage. Similarly, mounting of a conventional heat exchanger in the engine intake air stream does not provide a satisfactory solution due to the safety implications if a leak were to occur resulting in a fuel air mixture being provided to the engine, possibly creating a runaway condition. Use of water cooling from the engine radiator is not feasible because the temperature of the radiator fluid typically exceeds 150°F even at the outlet. A conventional cooling alternative of using the air conditioning system for the vehicle is not attractive since not all trucks, as well as many other applications requiring fuel cooling, do not come equipped with air conditioning. Additionally, fuel efficiencies and emissions from the vehicle would be dependent on the functionality of the air conditioning system in the vehicle. During winter operations diesel fuel can become jelled and cause fuel system freeze-up. Consequently, it is desirable to have the capability for fuel heating, especially during start up, to increase cold weather operating efficiency.

It is, therefore, desirable to have an apparatus for thermal control of fluids which is capable of both heating and cooling and is integral with existing engine systems to limit failure potential and hazard allowing its use with fuels. SUMMARY OF THE INVENTION

The present invention provides a fluid thermal management system which includes a heat exchanger mounted to receive inlet air to a turbocharger compressor as a thermal exchange medium to cool a working fluid. An embodiment of the heat exchanger has a tubular extension mounted to the inlet of the turbocharger compressor, a conduit for the working fluid, mounted for thermal contact of the fluid with an exterior surface of the extension, and a plurality of fins mounted in thermal contact with an interior surface of the extension and extending radially inwardly for heat transfer to the inlet air. The working fluid is transferred to the heat exchanger using a bypass valve mounted in a fluid line and controllable from a first position maintaining fluid flow in the line to a second position wherein at least a portion of the fluid is bypassed to an outlet. A temperature sensor for the working fluid is connected to a controller for controlling the bypass valve from the first position to the second position at a predetermined temperature. A first transfer line extends from the valve outlet to the heat exchanger and a second transfer line returns fluid from the heat exchanger.

Fluid heating is accomplished by employing a second heat exchanger, of substantially identical configuration to the first heat exchanger, mounted to receive outlet air from the turbocharger compressor as a thermal exchange medium to heat the working fluid and the bypass valve mounted in the fluid line is controllable from a first position maintaining fluid flow in the line to a second position wherein at least a portion of the fluid is bypassed to an first outlet and a third position wherein at least a portion of the fluid is bypassed to a second outlet. The controller, in response to the temperature sensor, controls the bypass valve from the first position to the second position at a first predetermined temperature and from the first position to the third position at a second predetermined temperature. A third transfer line extends from the second valve outlet to the second heat exchanger and a fourth transfer line returns fluid from the second heat exchanger.

For application as a diesel fuel temperature managment system, the fourth transfer line returns fuel from the second heat exchanger to a fuel tank and the system further includes a second bypass valve mounted in the fourth transfer line controllable from a first position maintaining fluid flow in the forth line to a second position bypassing at least a portion of the fuel in the forth line to an outlet and a fifth transfer line connects the outlet of the second bypass valve to the fuel pump supply. The controller also controls the second bypass valve in response to predetermined readings from the temperature sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

The details and features of the present invention will be more clearly understood with respect to the detailed description and drawings in which:

FIG.l is a schematic diagram of an embodiment of the invention with a pictorial representation of the turbocharger mounted heat exchangers on the inlet and outlet of the compressor;

FIG. 2 is a block diagram of a diesel engine employing the invention for fuel cooling and heating;

FIG. 3 is a partial cutaway of a heat exchanger employed in a first embodiment of the present invention; and

FIG. 4 is a partial cutaway of a heat exchanger employed in a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings, FIG. 1 shows an embodiment of the present invention in partial pictorial form with a conventional turbocharger 10 having a compressor housing 12 which encloses the multibladed compressor wheel and includes an inlet 14 and an outlet 16. A turbine housing 18 encloses the turbine, receiving exhaust from the engine exhaust manifold to drive the compressor through a standard shaft carried in a conventional center housing and bearing assembly (not shown). Cooling of a working fluid, such as diesel fuel, is accomplished with a first heat exchanger 20. The heat exchanger incorporates a tubular extension 22 mounted to the inlet to the compressor housing. A conduit 24 to carry the working fluid is placed in thermal contact with an exterior surface of the extension. A plurality of fins 26 are mounted on the interior surface of the extension and extend radially into the intake air flowing into the turbocharger compressor. Inlet air to the compressor is at approximately ambient air temperature, not typically exceeding 105°F and provides a mass flow sufficient to provide adequate heat transfer to the fluid. For most operating conditions, this provides adequate cooling for the exemplary diesel fuel cooling embodiment. In many instances, the ambient air temperature is much lower and therefor has the ability to reduce fuel temperature even lower which may further improve engine performance resulting in better fuel mileage and reductions in emissions.

The fins mounted interior to the extension add sufficient surface area for the heat exchanger to efficiently operate as a heat sink and provide a secondary effect of inlet airflow control to orient and smooth airflow into the compressor for enhanced compressor performance. As shown in detail in FIG. 3, the longitudinal shape and mounting profile of the fins can be controlled to induce pre-swirl in the flow if desired. For the embodiment shown in FIG. land 3, the fluid conduit is formed from multipassage extruded tube wrapped helically around the extension and bonded using brazing or thermally conductive adhesive techniques and provided with an inlet fitting 28 and an outlet fitting 30.

A second embodiment for the heat exchanger is shown in FIG. 4 which displays a turbulating fin 32 mounted in a serpentine helical shape on the external surface of the extension. A sleeve 34 is mounted over the turbulating fin in close contact to provide a flow path for the fluid. The sleeve is sealed at each end and inlet and outlet fittings 36 and 38 are provided for fluid transfer into the heat exchanger. The turbulator provides flow direction and promotes heat transfer from the fluid. Bonding of the turbulator and sleeve to the extension is accomplished by brazing or thermally conductive adhesive techniques. A second heat exchanger 40 is employed on the compressor housing outlet to provide fluid heating when desired. The configuration of the outlet mounted heat exchanger is identical to that described previously with respect to the inlet mounted heat exchanger. Charge air from the outlet of the turbocharger compressor typically attains temperatures approaching 450°F due to compression and also has sufficient mass flow to provide adequate fluid heating, when desired.

The heat exchanger configuration for the embodiments shown in the drawings maintains fluid separation from the inlet air by maintaining the fluid flowpath exterior to the extension. In the diesel fuel exemplary embodiment, this virtually eliminates the possibility for fuel from any leak to enter the engine intake air stream. Further, the heat exchangers are mountable on a conventional turbocharger without interfering with standard elements such as a wastegate control valve 42 and can, therefore, be supplied as original equipment or as an aftermarket add-on.

Referring to FIG. 2, a system installation of the invention for fuel temperature management cooperates with existing diesel fuel system components. Diesel fuel is stored in a vehicle mounted tank 44 and extracted by a transfer pump 46 to flow through a conventional filter, water separater and heater unit 48. A supply pump 50 further pressurizes and pumps fuel from the filter/separator to injector manifolds 52 which carry fuel to the injectors in the engine. A return line 54 from the filter/separater to the tank accomodates differing flow rates of the transfer pump and supply pump at varying engine operating conditions. Excess fuel not supplied to the engine cylinders by the injectors flows from the injector manifolds through a second return line 56 to the fuel tank.

The present invention provides a temperature management controller 58 which receives input from a temperature sensor 60, shown in the embodiment in the drawings as mounted in the fuel tank. A multiport bypass valve 62 is controlled by the temperature management controller, which upon sensing fuel temperature exceeding a predetermined value of approximately 150°F, bypasses flow of at least a portion of the fuel in the return line through the fuel cooler which comprises the inlet heat exchanger 20 as described with respect to FIG. 1. Inlet air for the engine passes through a conventional air filter 64 through the inlet heat exchanger to the compressor inlet, providing sufficient mass for thermal transfer cooling the diesel fuel, which then flows back into the return line to the fuel tank.

In cold weather operation, the temperature management controller, upon sensing a second predetermined temperature indicating potential fuel gellation, controls bypass valve 62 to bypass flow of at least a portion of the fuel in the return line to the fuel heater whcih comprises the outlet heat exchanger 40 which receives high temperature air exiting the turbocharger compressor. Heated fuel is then routed to the return line and the fuel tank. A second bypass valve 66 is controlled by the temperature management system to bypass at least a portion of the fuel flow directly for injection into the engine when temperature parameters so indicate.

Having now described the invention in detail as required by the patent statutes, those skilled in the art will recognize modifications and substitutions to the specific embodiments disclosed herein. Such modifications and substitutions are within the scope and intent of the present invention as defined in the following claims.

Claims

WHAT IS CLAIMED IS:

1. A fluid thermal management system comprising: a heat exchanger mounted to receive inlet air to a turbocharger compressor as a thermal exchange medium to cool a working fluid; and means for transferring the working fluid to the heat exchanger.

2. A fluid thermal management system as defined in claim 1 wherein the heat exchanger comprises: a tubular extension mounted to the inlet of the turbocharger compressor; a conduit for the working fluid, mounted for thermal contact of the fluid with an exterior surface of the extension; and a plurality of fins mounted in thermal contact with an interior surface of the extension and extending radially inwardly for heat transfer to the inlet air.

3. A fluid thermal management system as defined in claim 2 wherein the conduit comprises an extruded tube helically wrapped around the tubular extension and bonded thereto.

4. A fluid thermal management system as defined in claim 2 wherein the conduit comprises: a turbulating fin mounted to the exterior surface of the extension; a sealed sleeve mounted in close contact with the turbulating fin and substantially concentrically with the extension to form a fluid flow passage between an interior surface of the sleeve and the exterior surface of the extension; and fluid inlet and outlet means for transferring fluid into and out of the sleeve.

5. A fluid thermal management system as defined in claim 1 further comprising: a second heat exchanger mounted to receive outlet air from a turbocharger compressor as a thermal exchange medium to heat a working fluid; and means for transferring the working fluid to the second heat exchanger.

6. A fluid thermal management system as defined in claim 5 wherein the first heat exchanger comprises: a tubular extension mounted to the inlet of the turbocharger compressor; a first conduit for the working fluid, mounted for thermal contact of the fluid with an exterior surface of the inlet extension; and a plurality of fins mounted in thermal contact with an interior surface of the inlet extension and extending radially inwardly for heat transfer to the inlet air, and wherein the second heat exchanger comprises: a tubular extension mounted to the outlet of the turbocharger compressor; a second conduit for the working fluid, mounted for thermal contact of the fluid with an exterior surface of the outlet extension; and a plurality of fins mounted in thermal contact with an interior surface of the outlet extension and extending radially inwardly for heat transfer to the inlet air.

7. A fluid thermal management system as defined in claim 6 wherein each of the first and second conduits comprise an extruded tube helically wrapped around the tubular extension and bonded thereto.

8. A fluid thermal management system as defined in claim 6 wherein each of the first and second conduits comprise: a turbulating fin mounted to the exterior surface of the extension; a sealed sleeve mounted in close contact with the turbulating fin and substantially concentrically with the extension to form a fluid flow passage between and interior surface of the sleeve and the exterior surface of the extension; and fluid inlet and outlet means for transferring fluid into and out of the sleeve.

9. A fluid thermal management system as defined in claim 1 wherein the transferring means comprises: a bypass valve mounted in a fluid line and controllable from a first position maintaining fluid flow in the line to a second position wherein at least a portion of the fluid is bypassed to an outlet; a temperature sensor for the working fluid; a controller responsive to the temperature sensor and controlling said bypass valve from the first position to the second position at a predetermined temperature; a first transfer line extending from the valve outlet to the heat exchanger; and a second transfer line returning fluid from the heat exchanger.

10. A fluid thermal management system as defined in claim 5 wherein the transferring means comprises: a bypass valve mounted in a fluid line and controllable from a first position maintaining fluid flow in the line to a second position wherein at least a portion of the fluid is bypassed to an first outlet and a third position wherein at least a portion of the fluid is bypassed to a second outlet; a temperature sensor for the working fluid; a controller responsive to the temperature sensor and controlling said bypass valve from the first position to the second position at a first predetermined temperature and from the first position to the third position at a second predetermined temperature; a first transfer line extending from the first valve outlet to the first heat exchanger; a second transfer line returning fluid from the first heat exchanger; a third transfer line extending from the second valve outlet to the second heat exchanger; and a fourth transfer line returning fluid from the second heat exchanger.

11. A fluid thermal management system as defined in claim 10 wherein the fluid is diesel fuel and the fourth transfer line returns fuel from the second heat exchanger to a fuel tank, the system further comprising: a second bypass valve mounted in the fourth transfer line controllable from a first position maintaining fluid flow in the forth line to a second position bypassing at least a portion of the fuel in the forth line to an outlet; a fifth transfer line connecting the outlet of the second bypass valve to a fuel pump supply; and means for controlling the second bypass valve.

12. A fluid thermal management system as defined in claim 2 wherein the plurality of fins are shaped longitudinally in the inlet extension to enhance inlet flow for improved compressor performance.

13. A fluid thermal management system as defined in claim 12 wherein the plurality of fins induce pre-swirl in the compressor inlet flow.

14. A fluid thermal management system as defined in claim 6 wherein the plurality of fins are shaped longitudinally in the outlet extension to enhance outlet flow for improved compressor performance.

15. A fluid thermal management system as defined in claim 14 wherein the plurality of fins are shaped as a diffuser.