DUCT FOR ENGINE BAY COOLING AND VENTILATION

Abstract

An air cooling system provides cooling air within an engine bay of a vehicle. The vehicle includes a radiator and a cooling fan, the cooling fan is operable to force air to flow through the radiator, and the cooling fan is also operable to blow air within a blow zone away from the cooling fan and into the engine bay. The air cooling system includes a duct having a first end that defines an inlet, a second end that defines an outlet, and a sidewall that extends between the first end and the second end. The duct is operable to be mounted to the vehicle with the second end and the outlet disposed within the downstream blow zone such that air exiting the outlet is blown by the cooling fan toward the engine bay.

Description

FIELD

The present disclosure relates cooling and ventilation and, more particularly, to a duct that cools and ventilates an engine bay of a vehicle.

BACKGROUND

Vehicles can include an engine, such as an internal combustion engine. The engine can be mounted within an engine bay of the vehicle. Combustion of fuel within the engine can produce heat. Excess heat in the engine and/or in surrounding structures can negatively impact operation of the vehicle.

Therefore, it is desirable to include a cooling system that removes heat from the engine and/or from surrounding structures. For instance, many vehicles include a fluid cooling system that pumps a coolant (e.g., antifreeze) between the engine and at least one heat exchanger (e.g., a radiator). During operation of the fluid cooling system, the coolant can remove heat from the engine, and the heat can be removed from the system via the heat exchanger.

SUMMARY

An air cooling system is disclosed that provides cooling air within an engine bay of a vehicle. The vehicle includes a radiator and a cooling fan, the cooling fan is operable to force air to flow through the radiator, and the cooling fan is also operable to blow air within a blow zone away from the cooling fan and into the engine bay. The air cooling system includes a duct having a first end that defines an inlet, a second end that defines an outlet, and a sidewall that extends between the first end and the second end. The duct is operable to be mounted to the vehicle with the second end and the outlet disposed within the downstream blow zone such that air exiting the outlet is blown by the cooling fan toward the engine bay.

Moreover, a vehicle is disclosed that includes a vehicle body defining an engine bay. The vehicle also discloses a radiator and a cooling fan. The cooling fan is operable to force air to flow through the radiator, and the cooling fan is also operable to blow air within a blow zone away from the cooling fan and toward the engine bay. Moreover, the vehicle includes a duct having a first end that defines an inlet, a second end that defines an outlet, and a sidewall that extends between the first end and the second end. The duct is mounted to the vehicle body with the second end and the outlet disposed within the downstream blow zone such that air exiting the outlet is blown by the cooling fan toward the engine bay.

Further areas of applicability of the teachings of the present disclosure will become apparent from the detailed description, claims and the drawings provided hereinafter, wherein like reference numerals refer to like features throughout the several views of the drawings. It should be understood that the detailed description, including disclosed embodiments and drawings referenced therein, are merely exemplary in nature intended for purposes of illustration only and are not intended to limit the scope of the present disclosure, its application or uses. Thus, variations that do not depart from the gist of the present disclosure are intended to be within the scope of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a vehicle engine bay with an air cooling system according to exemplary embodiments of the present disclosure;

FIG. 2 is a top view of the vehicle engine bay and air cooling system of FIG. 1;

FIG. 3 is a perspective view of a duct of the air cooling system of FIG. 1;

FIG. 4 is a side view of additional embodiments of the duct of the present disclosure;

FIG. 5 is a sectional view of additional embodiments of the duct of the present disclosure;

FIG. 6 is a sectional view of additional embodiments of the duct of the present disclosure;

FIG. 7 is a perspective view of a pair of ducts according to additional embodiments of the present disclosure; and

FIG. 8 is an upstream view of the ducts of FIG. 7.

DETAILED DESCRIPTION

Referring initially to FIGS. 1-3, an air cooling system 10 is illustrated according to exemplary embodiments of the present disclosure. As will be discussed in detail, the air cooling system 10 can cool (i.e., remove heat) from components located in an engine bay 12 (FIGS. 1 and 2) of a vehicle 13 (partially represented by broken lines in FIG. 1).

The vehicle 13 can be a car, truck, van, sports utility vehicle, or any other type. The vehicle 13 can define a plurality of axes, including a roll axis X, a pitch axis Y, and a yaw axis Z. The roll axis X defines a forward/rearward direction, the pitch axis Y defines a cross-vehicle direction, and the yaw axis Z defines a vertical direction.

The vehicle 13 can also include an engine 14 and a vehicle frame 16 that connects to and supports the engine 14 at plural engine mounts 18. The engine 14 can be received within the engine bay 12. The vehicle 13 can further include an exterior surface, which is partially represented by broken lines in FIG. 1, and which can be defined by a vehicle hood, doors, body panels, tires, and a front fascia 24.

Moreover, the vehicle 13 can include a radiator 20 of a known type and a fan 22 of a known type. The radiator 20 and fan 22 can be disposed forward of the engine bay 12 as shown in FIGS. 1 and 2. In the embodiments illustrated, the fan 22 is disposed behind the radiator 20 in the forward/rearward direction X, and the radiator 20 is disposed behind the front fascia 24 in the forward/rearward direction X.

As is known, the radiator 20 can be fluidly connected to the engine 14 such that a coolant (e.g., antifreeze) flows cyclically therebetween. The coolant can receive heat from the engine 14, and the heat can be removed from the coolant as the coolant flows through the radiator 20. The fan 22 can operate to draw or force air through the radiator 20 (i.e., over fins of the radiator 20. Accordingly, the air can gather heat from the coolant as the air flows across the radiator 20.

The fan 22 can also define a blow zone 42. The blow zone 42 is defined as the region in the engine bay 12 that is downstream from the fan 22 and that directly receives air propelled from the fan 22. In some embodiments, the boundaries 43 of the blow zone 42 can be defined by an imaginary cylinder or imaginary truncated cone (i.e., frusto-conic shape) that extends rearward from the fan 22 and that is coaxial with the fan 22 (FIGS. 1 and 2). Thus, the fan 22 can blow air within the blow zone 42, away from the fan 22 and into the engine bay 12.

It will be appreciated that the engine 14, the engine mounts 18, portions of the frame 16 and/or other portions of the vehicle 13 can heat up during operation of the engine 14. As mentioned, the radiator 20 can operate to remove some of this heat. Also, as will be discussed, the air cooling system 10 can provide additional cooling to at least some of the components in the engine bay 12. Thus, the cooling system 10 can reduce temperatures in the engine bay 12 to improve operation of the vehicle 13.

As shown in FIGS. 1-3, the cooling system 10 can include one or more ducts 28a, 28b. In the embodiments illustrated, there are two ducts 28a, 28b disposed on opposite sides of the roll axis X. However, it will be appreciated that the system 10 can include any number of ducts 28a, 28b. The ducts 28a, 28b can be mirror images of each other, or the ducts 28a, 28b can vary. For purposes of discussion, it will be assumed that the duct 28b shown in FIG. 3 is largely representative of the other duct 28a. As will be described, airflow through the ducts 28a, 28b can bypass the radiator 20 and fan 22 to flow into the blow zone 42 within the engine bay 12.

As shown in FIG. 3, the duct 28b can be elongate and hollow. The duct 28b can be made of any suitable material, such as a polypropylene or other polymer, sheet metal, etc. Also, the duct 28b can be relatively lightweight.

Specifically, the duct 28b can include a first end 30 that defines an inlet 32, a second end 34 that defines an outlet 36, and a sidewall 38 that defines a passage 40. The passage 40 can terminate at the inlet 32 and can terminate at the opposite end at the outlet 36.

The sidewall 38 can extend continuously between the first and second ends 30, 34 and can curve along a longitudinal axis L. In some embodiments, the sidewall 38 can have a substantially constant thickness along the longitudinal axis L. Also, the duct 28b can have a generally hollow, rectangular cross section taken perpendicular to the longitudinal axis L, and this cross section can remain hollow and rectangular for the majority of the longitudinal length of the duct 28b.

The sidewall 38 can include a converging portion 39 near the first end 30 that converges into a tube portion 41. The tube portion 41 can have a relatively constant cross section along the axis L, and the tube portion 41 can be integrally joined to the second end 34 of the duct 28b. Also, the second end 34 and the outlet 36 can taper outward radially from the longitudinal axis L of the duct 28b (i.e., the second end 34 can be flared, the second end 34 can include a diverging section, etc.). Moreover, in the embodiments illustrated in FIGS. 1-3, the longitudinal axis L curves from the inlet 32 to the outlet 36 both toward the roll axis X and vertically upward in the vertical direction Z.

To attach the duct 28b to the vehicle, the first end 30 can be attached to the fascia 24. In some embodiments, the first end 30 is mounted to the fascia 24 below the radiator 20 (in the vertical direction Z) as shown in FIG. 1. However, the first end 30 could be mounted to any other structure relative to the radiator 20. The first end 30 can be connected to the fascia 24 via fasteners, adhesive, or in any other suitable fashion. Also, the sidewall 38 can be connected to surrounding structures, such as portions of the vehicle frame 16. In this regard, the sidewall 38 can include flanges (not shown) through which fasteners can extend to fix the sidewall 38 to the frame 16, etc. It will be appreciated that the duct 28a can be mounted substantially similar, albeit on the opposite side of the roll axis X.

Positioned as such, the ducts 28a, 28b can extend rearward from the fascia 24, the converging portions 39 can curve toward the roll axis X, and the tube portions 41 can curve upward vertically. As shown in FIG. 1, the tube portions 41 can extend upward at an acute angle relative to the roll axis X. Accordingly, the second ends 34 and the outlets 36 can be disposed within the blow zone 42 that is defined downstream of the fan 22.

The fascia 24 can include an openings 26 (FIG. 1) therethrough that each correspond in shape and size to the respective inlet 32 such that the inlet 32 and the respective openings 26 are fluidly connected and coaxial. Accordingly, when the vehicle 13 is travelling forward, the vehicle 13 encounters a headwind, etc., a positive pressure bias can be generated near the openings 26 in the fascia 24. As such, air can flow through the openings 26 and into the respective duct 28a, 28b. This air can flow and accelerate through the converging portions 39. The air can flow downstream through the tube portions 41, and the air can exit the ducts 28a, 28b via the outlets 36.

When the ducts 28a, 28b are mounted to the vehicle 13 as described above, the first ends 30 and inlets 32 can be disposed forward (i.e., upstream) relative to the radiator 20 and fan 22, and the ducts 28a, 28b each curve partially around the radiator 20 and fan 22. Thus, airflow through the ducts 28a, 28b bypasses the radiator 20 and fan 22. Also, because of the curvature of the ducts 28a, 28b, the second ends 34 and outlets 36 can be at least partially disposed directly within the blow zone 42 of the fan 22. Accordingly, air exiting the duct 28a, 28b can be propelled within the blow zone 42 by the fan 22 toward the engine 14, the engine mounts 18, etc. Thus, the relatively cooler air flowing through and exiting the ducts 28a, 28b can flow in the direction of components that would benefit from cooler operating conditions (e.g., the engine 14, the mounts 18, etc.) and intermingle with the hot air drawn through the radiator 20 by the radiator fan 22 to reduce the overall temperature of the air in and moving through the engine bay 12.

In some embodiments represented in FIG. 1, the second ends 34 can be pointed generally at a respective one of the engine mounts 18 such that the airflow from the outlets 36 can be directed thereto. Accordingly, the engine mounts 18 can be particularly cooled by airflow from the ducts 28a, 28b. It will be appreciated, however, that the second ends 34 could be pointed at any particular area or component within the engine bay 12. As mentioned, the second ends 34 can also taper outward radially to thereby reduce turbulence in the lateral expansion of the airflow exiting the ducts 28a, 28b and to thereby increase flow volume of the air toward the respective engine mount 18 or other component within the engine bay 12.

Thus, the air cooling system 10 can help cool the engine 14, the frame 16, the engine mounts 18, and/or other components within the engine bay 12. Because the engine 14 can run at lower temperatures, the engine 14 can operate more efficiently, the fuel economy of the vehicle 13 can be improved, and other known advantages can result. Additionally, the ducts 28a, 28b can focus air at predetermined areas within the engine bay 12 such that the air cooling system 10 can cool those areas. Also, the ducts 28a, 28b can be tailored for a specific vehicle 13, a specific vehicle engine 14, a specific engine bay 12, etc. Moreover, the air cooling system 10 is relatively compact, lightweight, and does not dramatically increase part counts for the vehicle 13.

Referring now to FIG. 4, additional embodiments of the air cooling system 110 are illustrated. Components that correspond to those of the embodiments of FIGS. 1-3 are indicated with corresponding reference numbers increased by 100.

As shown, the system 110 is substantially similar to the system 10 of FIGS. 1-3. However, the duct 128a includes one or more sidewall openings 144 that extend transversely through the sidewall 138. In the embodiments illustrated, there are three sidewall openings 144; however, there can be any number of openings 144. The sidewall openings 144 are arranged generally successively along the axis L of the duct 128a. Moreover, the openings 144 can be generally crescent-shaped or can have any other suitable shape. Also, the openings 144 can be aligned along the duct 128a, the openings 144 can be spaced or staggered about the longitudinal axis of the duct 128a, or the openings 144 can have any other suitable arrangement on the duct 128a.

The openings 144 can be disposed adjacent the second end 134 such that the sidewall openings 144 are disposed within the blow zone 142 of the fan 122. Accordingly, the sidewall openings 144 are operable to receive airflow directly from the fan 122, and this air can flow out of the duct 128a via the outlet 136. As a result of this airflow through the openings 144, air pressure at the inlet 132 can be significantly higher than air pressure at the outlet 136. Accordingly, air can be biased to flow in only one direction (i.e., into the duct 128a via the inlet 132 and out of the duct 128a via the outlet 136). This pressure differential and resulting biasing effect can also be created if the cross sectional area of the inlet 132 is significantly larger than that of the outlet 136.

Accordingly, this biasing effect can further facilitate airflow into the engine bay of the vehicle. For instance, when the vehicle is stopped or is moving relatively slowly, the fan 122 can blow air into the sidewall openings 144 to bias air into the duct 128a via the inlet 132 and out of the duct 128a via the outlet 136. Thus, the air cooling system 110 can cool the components in the engine bay even at low vehicle speeds.

Referring now to FIG. 5, additional embodiments of the air cooling system 210 are illustrated. Components that correspond to those of the embodiments of FIGS. 1-3 are indicated with corresponding reference numbers increased by 200.

The system 210 is substantially similar to the embodiments of FIGS. 1-3 except that the system 210 additionally includes a compressed air source 252 (e.g., a tank of compressed air that is mounted to the vehicle frame, etc.). The system 210 further includes a compressed air chamber 246. The chamber 246 can be a hollow ring that annularly and concentrically extends about the first end 230 of the duct 228a. The compressed air source 252 can be fluidly connected to the compressed air chamber 246 as represented by a broken line in FIG. 5. Also, the system 210 can include at least one compressed air opening 248 that extends through the sidewall 238 adjacent the first end 230 and that provide fluid communication between the compressed air chamber 246 and the passage 240 of the duct 228a. The opening 248 can extend from the chamber 246 in a downstream direction relative to the duct 228a, can curve in the upstream direction, and can terminate near the first end 230 of the duct 228a. The cross sectional area of the opening 248 can also taper gradually downward from the chamber 246 and can be very small when it terminates at the duct 228a.

The system 210 can further include a sensor 254, such as a vehicle speed sensor or a thermometer. The sensor 254 can be in operative communication with a processor 255, such as the vehicle's Engine Control Unit (ECU).

During operation, the sensor 254 can detect conditions of the vehicle and communicate corresponding signals to the processor 255. If the sensor 254 detects a predetermined condition (e.g., vehicle speed below a threshold speed and/or temperature in the engine bay above a threshold temperature), then the processor 255 can cause the compressed air source 252 to selectively inject compressed air into the compressed air chamber 246. This compressed air can move through the opening 248 and into the duct 228a to flow toward the engine bay. Thus, the system 210 can selectively provide additional air into the engine bay via the duct 228a for cooling if vehicle speed is low (e.g., below 2 mph), if temperatures in the engine bay are high (e.g., above 250° F.), or if other predetermined conditions exist.

In some embodiments, the system 210 could be configured as a so-called “Coanda Propelling Device” to generate a “Coanda Effect.” More specifically, the airflow entering the duct 228a from the chamber 246 can have relatively high pressure and low volume and can then transform to relatively low pressure and high volume airflow within the duct 228a. Accordingly, the airflow from the chamber 246 can induce air outside the vehicle to flow into the duct 228a. This can be effective, for instance, when the vehicle is traveling at low speeds, etc. Thus, if the sensor 254 detects low vehicle speeds, then the processor 255 can cause the chamber 246 to inject compressed air through the opening 248 into the duct 228a to cause the Coanda effect.

It will be appreciated that the chamber 246 and opening 248 can be located very near the inlet of the duct 228a to thereby increase the Coanda effect. Also, the opening 248 can be located upstream of the converging section 39 (FIG. 3) of the duct 228a to also increase the Coanda effect. The shape, size, and/or other features of the chamber 246 and opening 248 can also exhibit a so-called “Coanda profile” to thereby induce air outside the vehicle to flow into the duct 228a.

The system 210 can generate the Coanda effect under any suitable vehicle conditions. As stated, the sensor 254 can detect that the vehicle is travelling at low speeds (i.e., below a predetermined threshold speed), and the processor 255 can activate the compressed air source 252 as a result. The sensor 254 can detect other conditions as well for activating the compressed air source 252. For instance, the sensor 254 can trigger activation of the compressed air source 252 if the sensor 254 detects engine RPMs below a predetermined threshold, engine temperatures above a predetermined threshold, fluid pressures (e.g., engine coolant pressure) above a predetermined threshold, ambient temperatures above a predetermined threshold, barometric pressure above a predetermined threshold, windspeeds below a predetermined threshold, engine torque and/or power load above a predetermined threshold, and/or sunlight load above a predetermined threshold. Moreover, the sensor 254 can trigger activation of the compressed air source 252 according to a preprogrammed time cycle duration. Furthermore, the sensor 254 can trigger activation of the compressed air source 252 according to a predetermined vehicle transmission mode. Moreover, it will be appreciated that the processor 255 can operate according to preprogrammed logic and algorithms to function according to one or more of these detectable vehicle conditions.

Referring now to FIG. 6, additional embodiments of the air cooling system 310 are illustrated. Components that correspond to those of the embodiments of FIGS. 1-3 are indicated with corresponding reference numbers increased by 300.

The system 310 is substantially similar to the embodiments of FIGS. 1-3, except that the duct 328a can additionally include one or more projections 356 that project from an inner surface of the sidewall 338 into the passage 340. The projections 356 can be bumps, ridges, rails, or other type. The projections 356 can be included on the lower, inner surface of the sidewall 338 (e.g., on the converging portion of the duct 328a).

The projections 356 can be integrally connected to the sidewall 338 or can be removably attached. Moreover, in some embodiments, the projections 356 can be formed by applying force to the exterior of the sidewall 338 toward the interior of the passage 340 to deform the sidewall 338 and create the projections 356.

As shown in FIG. 6, if a stone, pebble, debris, or other projectile 357 enters the duct 328a via the inlet 332, the projectile 357 is likely to impact one or more of the projections 356, thereby reducing the momentum of the projectile 357. The projectile 357 is likely to rebound back toward the inlet 332 instead of travelling further down the duct 328a.

Accordingly, the projections 356 can inhibit the projectile 357 from travelling through the duct 328a and into the engine bay. It will be appreciated that other features could be included for blocking projectiles 357 in addition to or in alternative to the projections 356. For instance, the system 310 could include a thin mesh screen that extends across the passage 340 and blocks certain projectiles. It will also be appreciated that the projections 356 can be included at any suitable location for blocking the projectiles 357.

Referring now to FIGS. 7 and 8, additional embodiments of the ducts 428a, 428b are illustrated. Components that are similar to those of the embodiments of FIGS. 1-3 are illustrated with corresponding reference numerals increased by 400. It will be appreciated that one or more features of the ducts 428a, 428b could be included in any of the air cooling systems 10, 110, 210, 310 discussed above.

The ducts 428a, 428b can be substantially similar those of the embodiments of FIGS. 1-3, except that the ducts 428a, 428b can each have a clam shell construction. More specifically, the ducts 428a, 428b can each include an upper shell 458a, 458b and a lower shell 460a, 460b that are joined together along a seam 461a, 461b. The upper and lower shells 458a, 458b, 460a, 460b can each extend along the entire respective longitudinal axis of the duct 428a, 428b, and the seam 461a, 461b can extend along both the inboard and outboard side of the duct 428a, 428b. The seam 461a, 461b can be welded together (e.g., vibration welded, etc.). Accordingly, the ducts 428a, 428b can be constructed in a relatively inexpensive manner.

Moreover, the ducts 428a, 428b can each include respective notches 462 in the upper and lower shells 458a, 458b, 460a, 460b, adjacent the first end 430a, 430b of the duct 428a, 428b. The notches 462 can receive surrounding structures, such as portions of the fascia, air guiding panels of the radiator, etc. Accordingly, the notches 462 can allow the ducts 428a, 428b to mount to the vehicle in a compact manner.

Moreover, the ducts 428a, 428b can include one or more respective flanges 464a, 464b. The flanges 464a, 464b can be integrally or otherwise connected to the respective shells 458a, 458b, 460a, 460b at any suitable location. The flanges 464a, 464b can project away therefrom and can fixedly attach to the vehicle frame, to the fascia, etc. For instance, the flanges 464a, 464b can include openings for fasteners to attach to the frame, fascia, etc. Alternatively, the flanges 464a, 464b can be welded, adhesively, or otherwise attached to the frame, fascia, etc.

In summary, the air cooling system 10, 110, 210, 310 can be relatively inexpensive, lightweight, and effective for cooling components within the engine bay of a vehicle. The system 10, 110, 210, 310 can inject external air within the blow zone of the fan to increase airflow over the components in the engine bay. As such, the vehicle can operate at lower temperatures and can, therefore, operate more efficiently.

Claims

1. An air cooling system for providing cooling air within an engine bay of a vehicle, the vehicle including a radiator and a cooling fan, the cooling fan operable to force air to flow through the radiator, the cooling fan also operable to blow air within a blow zone away from the cooling fan and into the engine bay, the air cooling system comprising:

a duct having a first end that defines an inlet, a second end that defines an outlet, and a sidewall that extends between the first end and the second end, the duct operable to be mounted to the vehicle with the second end and the outlet disposed within the downstream blow zone such that air exiting the outlet is blown by the cooling fan toward the engine bay;

wherein a passage extends through the duct from the first end to the second end, the passage defined by an inner surface the inner surface including a projection that is operable to reduce momentum of a projectile that is moving through the passage from the first end toward the second end.

2. The air cooling system of claim 1, wherein the duct defines a longitudinal axis and wherein the outlet tapers outward radially from the longitudinal axis.

3. The air cooling system of claim 1, wherein the duct defines a longitudinal axis that curves, the duct operable to be mounted to the vehicle such that the longitudinal axis curves from the inlet to the outlet both toward a roll axis of the vehicle and vertically upward along a yaw axis of the vehicle,

4. The air cooling system of claim 1, wherein the duct is operable to be mounted to the vehicle with the first end and the inlet disposed forward relative to the cooling fan such that airflow through the duct from the inlet to the outlet bypasses the radiator and the cooling fan.

5. The air cooling system of claim 1, wherein the side wall includes at least one opening that receives airflow from the cooling fan to bias airflow into the inlet and out of the outlet.

6. The air cooling system of claim 5, wherein the at least one opening is disposed within the blow zone.

7. The air cooling system of claim 1, further comprising a compressed air source that is operable to selectively inject compressed air into the duct, a sensor that is operable to detect a predetermined condition of the vehicle, and a controller that causes the compressed air source to selectively inject compressed air into the duct to flow out of the outlet when the sensor detects the predetermined condition of the vehicle.

8. The air cooling system of claim 7, wherein the sensor is a vehicle speed sensor that is operable to detect a vehicle speed of the vehicle, the controller causing the compressed air source to selectively inject compressed air into the duct to flow out of the outlet when the vehicle speed sensor detects the vehicle speed below a predetermined threshold.

9. The air cooling system of claim 7, wherein the sensor is a temperature sensor that is operable to detect a temperature in the engine bay, the controller causing the compressed air source to selectively inject compressed air into the duct to flow out of the outlet when the vehicle speed sensor detects the temperature in the engine bay above a predetermined threshold.

10. The air cooling system of claim 7, further comprising a compressed air chamber that is in communication with the compressed air source and that includes a compressed air opening that extends through the sidewall and that is disposed adjacent the inlet, the opening configured to generate a Coanda effect and induce airflow into the inlet from outside the vehicle.

11. (canceled)

12. A vehicle comprising:

a vehicle body that defines an engine bay;

a radiator;

a cooling fan, the cooling fan operable to force air to flow through the radiator, the cooling fan also operable to blow air within a blow zone away from the cooling fan and toward the engine bay; and

a duct having a first end that defines an inlet, a second end that defines an outlet, and a sidewall that extends between the first end and the second end, the duct mounted to the vehicle body with the second end and the outlet disposed within the downstream blow zone such that air exiting the outlet is blown by the cooling fan toward the engine bay,

wherein a passage extends through the duct from the first end to the second end, the passage defined by an inner surface, the inner surface including a projection that is operable to reduce momentum of a projectile that is moving through the passage from the first end toward the second end.

13. The vehicle of claim 12, wherein the duct is mounted to the vehicle body with the first end and the inlet disposed forward relative to the cooling fan such that airflow through the duct from the inlet to the outlet bypasses the radiator and the cooling fan.

14. The vehicle of claim 12, wherein the vehicle body defines a vertical direction, and wherein the duct is mounted to the vehicle body with the first end mounted below the radiator assembly in the vertical direction.

15. The vehicle of claim 12, wherein the side wall includes at least one opening that receives airflow from the cooling fan to bias airflow into the inlet and out of the outlet, wherein the at least one opening is disposed within the blow zone.

16. The vehicle of claim 12, further comprising a compressed air source that is operable to selectively inject compressed air into the duct, a sensor that is operable to detect a predetermined condition of the vehicle, and a controller that causes the compressed air source to selectively inject compressed air into the duct to flow out of the outlet when the sensor detects the predetermined condition of the vehicle.

17. The vehicle of claim 16, wherein the sensor is a vehicle speed sensor that is operable to detect a vehicle speed of the vehicle, the controller causing the compressed air source to selectively inject compressed air into the duct to flow out of the outlet when the vehicle speed sensor detects the vehicle speed below a predetermined threshold.

18. The vehicle of claim 16, wherein the sensor is a temperature sensor that is operable to detect a temperature in the engine bay, the controller causing the compressed air source to selectively inject compressed air into the duct to flow out of the outlet when the vehicle speed sensor detects the temperature in the engine bay above a predetermined threshold.

19. The vehicle of claim 16, further comprising a compressed air chamber that is in communication with the compressed air source and that includes a compressed air opening that extends through the sidewall and that is disposed adjacent the inlet, the opening configured to generate a Coanda effect and induce airflow into the inlet from outside the vehicle.

20. (canceled)