Vehicle cooling fan
A cooling fan for a vehicle. Many engine compartments of motor vehicles are small in size, and contain numerous components. Electric cooling fans are used to draw air through a radiator. Given the cramped conditions within the engine compartment, the exhaust of the fan cannot be directed into open air, but must impinge on one or more of the components within the compartment. This situation reduces velocity in the exhaust, and also reduces efficiency of the fan. The invention provides a collection of generally co-axial stators which divert the exhaust around the components, while retaining much of the velocity of the exhaust.
Latest VALEO, INC. Patents:
In modern motor vehicles, the engine compartment is becoming increasingly crowded, primarily because of (1) the placement of additional components into the engine compartment, (2) the reduction in volume of the engine compartment, primarily to reduce overall aerodynamic drag of the vehicle, and many other factors.
The crowded nature of the compartment can cause problems in the operation of a cooling fan, such as that illustrated in
The invention presents a stratagem for reducing the negative effects of the obstruction 9.
SUMMARY OF THE INVENTIONAn object of the invention is to provide an improved cooling fan for a vehicle.
A further object of the invention is to provide a cooling fan for a vehicle which operates efficiently in a confined environment.
In one form of the invention, stators are positioned in the exhaust stream of a cooling fan in a motor vehicle. The stators divert air into the radial direction, while increasing total airflow over the situation wherein the exhaust stream impinges on an obstacle it its path.
In one aspect, one embodiment comprises an apparatus, comprising: a fan which produces an exit flow; and vanes upstream of the obstacle which divert a portion of the exit flow into a radial direction.
In another aspect, one embodiment comprises an apparatus; comprising: a vehicle; within the vehicle, a cooling fan which generates a generally cylindrical airflow toward an obstruction downstream of said fan; and one or more stators between said fan and said obstruction, which turn generally axially flowing air into generally radially flowing air.
In still another aspect, one embodiment comprises an apparatus comprising: a generally axial-flow fan which produces exhaust having polar coordinates (r, z, theta) definable therein; vanes present in the exhaust, which increase radial component of the exhaust; and wherein vanes at different coordinates (r, theta, z) have different geometries.
In yet another aspect, one embodiment comprises an apparatus; comprising: a generally axial-flow fan which produces an exhaust, and means present in the exhaust for reducing a change in angle-of-attack of blades in the fan, which change is caused by an obstacle in the exhaust.
In another aspect, one embodiment comprises an apparatus; comprising: a cooling system; a generally axial-flow cooling fan for use in a vehicle having an obstruction in said vehicle downstream of the cooling fan which, if exhaust of the fan is allowed to reach the obstruction unimpeded, diverts the exhaust into radial directions with an average speed V1, and a set of stators between the fan and the obstruction, which divert the exhaust into radial directions with an average speed V2, higher than V1.
In yet another aspect, one embodiment comprises a method for improving cooling of an engine in a vehicle, said method comprises the steps of: situating a set of stators or vanes in an airflow path between a fan and an obstruction to diver exhaust into a generally reclined direction at a speed that exceeds the speed at which airflow is diverted by said obstruction.
These and other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
In
As
To aid in showing overall patterns, the arrows leading from the scale of relative pressures are labeled with round numbers, such as 1, 15, 35, and so on. These round numbers represent convenient approximate values. For example, the arrow labeled 60 originates at a point between 52.14 and 65.57 on the scale. The number 60 is a convenient intermediate value between those two numbers.
Two significant features of
Significantly, in
Stated more precisely,
Thus, under the invention, high total pressure is sustained for a longer radial distance from the fan tip diameter, compared with the case of
In
That is, the highest velocity in
The invention of
These convenient non-dimensional groupings allow plots of different experimental setups to be compared directly. For example, if a different fan speed were used or a fan of a different diameter, the plots of those two situations could be compared directly with that of
The pressure rise drops as flow increases because, as flow increases, the dynamic component of the total pressure becomes larger. Because the Fig. reports static pressure, static pressure drops as flow increases.
Plot 125 indicates that, with the obstruction present, but no stators present, torque remains somewhat constant, with a slight rise at about 0.22 units of flow coefficient.
Plot 130 indicates that, with the obstruction present and the stators installed, torque drawn form the motor is about the same as for plot 125, up to about 0.21 units of flow coefficient. Then, torque behavior drops.
More precisely, efficiency is computed as (P*F)/T
-
- wherein
- P is the pressure coefficient in
FIG. 13 , - F is the flow coefficient in
FIGS. 13, 14 , and 15, and - T is the torque coefficient in
FIG. 14 .
For example, for a flow coefficient F of 0.2, the pressure coefficient P in
A significant comparison can be made between curves 155 and 150. The condition without both stators and blockage is a curve of interest, but does not relate to an installed vehicle condition. Curve 150 shows higher efficiency than curve 155 for flow coefficient levels above 0.16. Typical on vehicle operating range for cooling fans of this type ranges from 0.16 at an idle condition to above 0.30 at higher vehicle speed operation. The combination of stators with the downstream blockage provides benefit throughout the entire on vehicle operating range
In one mode of operation, it is contemplated that the fan 24 operate above a flow coefficient of 0.25 at least 90 percent of the time.
Additional Considerations 1. The invention improves efficiency of the cooling system.
The net incoming air seen by the blade B is the vector sum of the two components 210 and 220, indicated in
However, the presence of the obstacle disrupts this optimal efficiency. While the particular mechanism of the disruption is complex, a simplified view is that the obstacle reduces the velocity of the air flowing through the fan 200. The disruption can be viewed as reducing the size of vector 220, as indicated in
In general, the fan 200 was not designed for this different vector 225, and efficiency is reduced.
In contrast, in
2. The vanes in cross section can assume airfoil shapes. These shapes can be different at different circumferential locations around the fan.
In general, the shapes of the vanes can be different at different coordinates. For example, in
In
In one embodiment, the inlet angles, or exit angles, or both, can be similar at similar angles theta, but at different angles theta, they can differ. For example, in
In addition, the similar angles can span a range of positions. For example, the angles in question can be similar from 3 o'clock to 6 o'clock.
In
In a related type of difference, the channel width W between different pairs of vanes is different: different pairs define different channel widths. The channel width W need not be constant. Thus, an average width can be considered, or the minimum or maximum width.
Similarly, an annulus can be defined in the exhaust of the fan. An annulus is a band between two circles of different diameter. For example, the rings of Saturn form an annulus. In one form of the invention, vanes can be present in all or part of an annulus of given inner diameter, but vanes may be absent from other annuli.
In
Therefore, in general, the airfoil shape of the vanes can be different, at different coordinates (r, theta, z). The difference includes the absence of vanes entirely at certain coordinates. The parameters of airfoil shape, such as chord length, thickness, inlet angle, and exit angle, are defined in the art of aerodynamics. As stated, these parameters can vary over the (r, theta, z) space.
Also, the vanes in the sector which covers the obstacle can be designed differently from vanes in other sectors. For example, in
3. The vanes can be ring-shaped, with the larger-diameter rings closer to the fan, and the smaller-diameter rings farther from the fan.
4. In one embodiment, radial struts generically indicated by dashed block 300 in
In many types of fans, such radial struts are shaped to re-direct exhaust air generated by the fan. For example, in
In one form of the invention, this re-direction does not occur, is not desired, and the radial struts are not designed to perform this re-direction.
It is recognized that any time an object is placed in a flow stream, some re-direction will occur. For example, if a flow stream is moving East, and encounters an object, part of the flow stream will flow North, part South, and part upward.
Similarly, if a flow stream generated by a fan encounters a radial strut, part of the flow stream will flow slightly tangentially, to avoid the strut.
Nevertheless, under the form of the invention in question, the struts are not designed to enhance or decrease this minimal amount of tangential flow. Stated another way, the impact on tangential flow is sought to be minimal, and the radial struts designed accordingly.
5. The fan-vane system is designed to be mounted within an engine compartment of a vehicle. Block 350 in
That is, with four-point mounting, the four points define a quadrilateral, such as a rectangle. Assume that the rectangle is vertical, facing south, and the two lower corners are anchored. If the left upper corner moves north, and the right upper corner moves south, then torsion is applied to the rectangle.
Such torsion does not occur in three-point mounting.
Numerous substitutions and modifications can be undertaken without departing from the true spirit and scope of the invention. What is desired to be secured by Letters Patent is the invention as defined in the following claims.
Claims
1. An apparatus comprising:
- a) a fan which produces an exit flow toward an obstacle in the exit flow; and
- b) vanes upstream of said obstacle which divert a portion of the exit flow into a radial direction.
2. The apparatus according to claim 1, wherein said fan, obstacle, and vanes are located in the engine compartment of a vehicle.
3. The apparatus according to claim 2, wherein said fan draws cooling air through a heat exchanger which cools engine coolant and/or a condenser that cools refrigerant for the vehicle air conditioning system.
4. The apparatus according to claim 1, wherein said fan is generally an axial flow type.
5. The apparatus according to claim 1, wherein said vanes mitigate reduction in fan efficiency caused by the obstacle.
6. The apparatus according to claim 4, wherein at least three vanes are present, and radial spacing between one pair of neighboring vanes is different from radial spacing between a second pair of neighboring vanes.
7. The apparatus according to claim 1, wherein a plurality of said vanes have different chord lengths.
8. The apparatus according to claim 1, wherein said fan is of the axial flow type and
- i) vanes which are relatively near the axis are relatively far from said fan, and
- ii) vanes which are relatively far from the axis are relatively near to said fan.
9. The apparatus according to claim 1, wherein said vanes are generally ring-shaped, and larger diameter vanes are closer to said fan than smaller diameter vanes.
10. The apparatus according to claim 1, wherein at least one of said vanes has an inlet angle IA-1 and another of said vanes has an inlet angle IA-2, different from IA-1.
11. The apparatus according to claim 1, wherein at least one of said vanes has an inlet angle IA-1 and another of said vanes has an inlet angle IA-2, is equal to IA-1.
12. The apparatus according to claim 1, wherein at least one vane has an exit angle EA-1 and another of said vanes has an exit angle EA-2, different from EA-1.
13. The apparatus according to claim 10, wherein all inlet angles of said vanes at similar angular positions are similar.
14. The apparatus according to claim 12, wherein all exit angles of vanes having similar angular positions are similar.
15. The apparatus according to claim 1, wherein the fan is generally an axial-flow type and at least some vanes span an arc of less than 360 degrees.
16. The apparatus according to claim 14, wherein vanes at different radii span different arcs.
17. The apparatus according to claim 1, wherein radial struts support the vanes, and the radial struts do not significantly re-direct tangential exhaust from the fan into axial flow.
18. The apparatus according to claim 1, wherein radial struts support the vanes, and re-direction of tangential exhaust from the fan into axial flow by the radial struts is minimal.
19. An apparatus, comprising:
- a) a vehicle;
- b) within the vehicle, a cooling fan which generates a generally cylindrical airflow toward an obstruction downstream of said fan; and
- c) one or more stators between said fan and said obstruction, which turn generally axially flowing air into generally radially flowing air.
20. The apparatus according to claim 19, wherein said fan, obstruction, and stators are located in the engine compartment of a vehicle.
21. The apparatus according to claim 19, wherein said fan draws cooling air through a heat exchanger which cools engine coolant and/or a condenser that cools refrigerant for the vehicle air conditioning system.
22. The apparatus according to claim 19, wherein said fan is an axial flow fan.
23. The apparatus according to claim 19, wherein the said vanes mitigate reduction in fan efficiency caused by the obstacle.
24. The apparatus according to claim 23, wherein at least three stators are present, and radial spacing between one pair of neighboring vanes is different from radial spacing between a second pair of neighboring vanes.
25. The apparatus according to claim 19, wherein different ones of said stators have different chord lengths.
26. The apparatus according to claim 19, wherein said fan has a central axis defined therein and
- i) stators which are relatively near the axis are relatively far from the fan, and
- ii) stators which are relatively far from the axis are relatively near to the fan,
27. The apparatus according to claim 19, wherein said stators are generally ring-shaped, and larger diameter stators are closer to the fan than smaller diameter vanes.
28. The apparatus according to claim 19, wherein one of said stators has an inlet angle IA-1 and another stator has an inlet angle IA-2, different from IA-1.
29. The apparatus according to claim 19, wherein one stator has an exit angle EA-1 and another stator has an exit angle EA-2, different from EA-1.
30. The apparatus according to claim 28, wherein all inlet angles of stators at similar angular positions are similar.
31. The apparatus according to claim 29, wherein all exit angles of stators having similar angular positions are similar.
32. The apparatus according to claim 19, wherein said fan is generally an axial-flow type and at least some stators span an arc of less than 360 degrees.
33. The apparatus according to claim 32, wherein stators at different radii span different arcs.
34. The apparatus according to claim 19, wherein radial struts support the stators, and the radial struts do not significantly re-direct tangential exhaust from the fan into axial flow.
35. The apparatus according to claim 19, wherein radial struts support the stators, and re-direction of tangential exhaust from said fan into axial flow by the radial struts is minimal.
36. An apparatus, comprising:
- a) a generally axial-flow fan which produces exhaust having polar coordinates (r, theta, z) defineable therein;
- b) vanes present in the exhaust, which increase radial component of the exhaust; and
- wherein vanes at different coordinates (r, theta, z) have different geometries.
37. The apparatus according to claim 36 and further comprising a vehicle having an engine compartment, wherein the fan and the vanes are located in the engine compartment.
38. The apparatus according to claim 36, wherein an obstacle is present in the exhaust, and the vanes divert exhaust around the obstacle.
39. The apparatus according to claim 36, wherein inlet angles of vanes at a common angle theta are similar.
40. The apparatus according to claim 36, wherein exit angles of vanes at a common angle theta are similar.
41. The apparatus according to claim 36, wherein, at a given z-coordinate, vane geometry is non-uniform for all theta.
42. The apparatus according to claim 36, wherein vanes at different r-coordinates span different angles theta.
43. The apparatus according to claim 19, wherein adjacent vane pairs define a channel therebetween, and different channels have different widths.
44. The apparatus according to claim 36, wherein a first vane of a first radius spans an arc A1, and a second vane of a second radius spans an arc A2, different from A1.
45. An apparatus, comprising:
- a) a generally axial-flow fan which produces an exhaust,
- b) means present in the exhaust for reducing a change in angle-of-attack of blades in the fan, which change is caused by an obstacle in the exhaust.
46. The apparatus according to claim 45, and further comprising a motor vehicle which carries said fan and the means in an engine compartment.
47. An apparatus, comprising:
- a) a cooling system;
- b) a generally axial-flow cooling fan for use in a vehicle having an obstruction in said vehicle downstream of the cooling fan which, if exhaust of the fan is allowed to reach the obstruction unimpeded, diverts the exhaust into radial directions with an average speed V1, and
- c) a set of stators between the fan and the obstruction, which divert the exhaust into radial directions with an average speed V2, higher than V1.
48. A method for improving cooling of an engine in a vehicle, said method comprising the steps of:
- situating a set of stators or vanes in an airflow path between a fan and an obstruction to divert exhaust in a generally radial direction at a speed that exceeds the speed at which airflow is diverted by said obstruction.
Type: Application
Filed: Mar 27, 2006
Publication Date: Sep 27, 2007
Applicant: VALEO, INC. (AUBURN HILLS, MI)
Inventors: Tao Hong (Farmington Hills, MI), John Savage (Rochester Hills, MI)
Application Number: 11/389,849
International Classification: F01P 7/10 (20060101); F01P 1/02 (20060101); B63H 1/16 (20060101);