WO2019035159A1 - Mobile body - Google Patents

Abstract

This vehicle 1 is provided with a fluid discharge device which, from a fluid discharge position 3 defined on a front surface of the vehicle 1 in the direction of travel, discharges a fluid with an air density lower than that of the outside air to outside of the vehicle 1.

Description

Moving body

The present invention relates to a mobile body provided with means for discharging fluid to the outside.

Conventionally, a cooling device such as an engine that cools the inside of a vehicle engine and engine rules with air when necessary is known (Patent Document 1). When the temperature in the engine rule rises above a certain temperature, air from the engine room flows out of the vehicle through a gap above the end of the engine compartment side.

JP-A-57-48123

On the other hand, in order to reduce the air resistance of the moving body, the inventors of the present invention reduce the air density in the area (main stream) outside the area (boundary layer) where the flow velocity of air in the vicinity of the moving body is slow. Found that it is effective.

However, in Patent Document 1, the air in the engine room is discharged from the gap above the end of the engine on the side of the vehicle room, thereby reducing the air density of the mainstream in a limited narrow range of the main flow around the moving body. I can only do that.

The present invention has been made in view of such conventional problems, and an object thereof is to reduce the air resistance of the moving body by reducing the mainstream air density around the moving body.

The movable body according to one aspect of the present invention discharges a fluid having a lower air density than the outside air toward the outside of the movable body from the fluid discharge position defined on the surface of the movable body in the forward traveling direction of the movable body.

According to one aspect of the present invention, it is possible to reduce the air resistance of the moving body by reducing the mainstream air density around the moving body.

FIG. 1 is a schematic view showing the flow of air along the surface of an automobile 1 generated around a traveling automobile 1 and a graph showing a pressure coefficient Cp of fluid. FIG. 2 is a cross-sectional view showing the bumper fascia of the front bumper 4 of the automobile 1. FIG. 3 is a perspective view showing the duct 5 formed on the bumper fascia of the front bumper 4. FIG. 4 is a schematic view showing an embodiment in which the exhaust gas of the engine 8 is discharged from the duct 5. FIG. 5 is an enlarged cross-sectional view showing the region Xe of FIG. 1 in an enlarged manner. FIG. 6A is a graph showing the relationship between the temperature of air and the air density. FIG. 6B is a graph showing the relationship between the molecular weight of air and the density of air. FIG. 6C is a graph showing the relationship between the partial pressure of water vapor in air and the density of air. FIG. 7 is a schematic view showing an example of an apparatus for generating a fluid having a temperature higher than that of the outside air. FIG. 8 is a schematic view showing an example of an apparatus for generating a fluid in which the partial pressure of water vapor is higher than that of the outside air. FIG. 9 is a schematic view showing a flow control valve 66 that changes the discharge flow rate of the exhaust gas from the engine 8. FIG. 10A is a graph showing three control patterns 52a, 52b, 52c for controlling the air discharge amount of the blower 32 based on the moving speed. FIG. 10B is a graph showing three control patterns 53a, 53b, 53c for controlling the air discharge amount of the blower 32 based on the temperature of the fluid. FIG. 10C is a block diagram showing an example of a control system that controls the air discharge amount of the blower 32 based on the temperature of the fluid or the moving speed of the automobile 1. FIG. 11A is a block diagram showing an example of a control system that controls the open / close state of the radiator shutter 36 according to the discharge flow rate of fluid. FIG. 11B is a schematic view showing a state in which the radiator shutter 36 is closed. FIG. 11C is a flowchart showing an example of a control procedure in the control system of FIG. 11A. FIG. 11D is a graph showing control patterns 54a, 54b, 54c for controlling the opening degree of the radiator shutter 36 based on the flow rate of fluid.

Embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same parts will be denoted by the same reference numerals and the description thereof will be omitted. Below, the case where a mobile body is a car is mentioned and explained.

<Flow of Air Around Car 1 Running>
As shown in FIG. 1, when viewed from the stationary system of the automobile 1, a flow of air along the surface of the automobile 1 is generated around the traveling automobile 1. FIG. 5 is an enlarged view of the area Xe of FIG. In the vicinity of the surface 20F of the automobile 1, the flow of air is delayed by the viscous friction generated between the air and the surface 20F of the vehicle body 20, and the boundary layer 41 is formed. In the boundary layer 41, the velocity of the air increases with distance from the surface 20F of the vehicle body 20, and the velocity of the air approaches the relative velocity of the automobile 1 with respect to the air.

In the outer region 43 outside the boundary 42 away from the surface 20F of the vehicle body 20, the influence of the viscous friction generated between the air and the surface 20F of the vehicle body 20 is no longer any longer, and the velocity of the air is It is almost equal to the relative velocity. The flow of air in the outer region 43 is referred to as the main flow 2.

Referring back to FIG. 1, the vehicle 1 is a fluid discharge device for discharging the fluid having a lower air density than the outside air to the outside of the vehicle 1 from the fluid discharge position defined on the surface of the vehicle 1 ahead of the vehicle 1 in the traveling direction. Equipped with As shown in the cross-sectional view of the upper part of FIG. 1, the fluid discharge position is, for example, a stagnation point 3 ahead in the traveling direction of the automobile 1. The stagnation point 3 is a point at which the pressure of the fluid is maximized as shown in the lower graph of FIG. 1, so the fluid discharged from the stagnation point 3 flows to the entire surface of the automobile 1 as the mainstream 2. Therefore, the air density of the mainstream 2 of a wide range can be reduced. In addition, the springing from stagnation point 3 is less likely to disturb the streamline of uniform flow and has the least effect. Thus, the fluid flows to the entire surface of the automobile 1, so the air resistance of the automobile 1 can be reduced. The horizontal axis of the lower graph of FIG. 1 indicates the position in the traveling direction of the vehicle 1, and the vertical axis indicates the pressure coefficient Cp.

In the embodiment, the fluid discharge position is not limited to stagnation point 3. In addition to this, for example, as shown in FIG. 2, it is also possible to define a fluid discharge position in the bumper fascia of the front bumper 4 of the automobile 1. That is, the fluid discharge device may discharge the fluid having a lower air density relative to the outside air to the outside of the vehicle 1 from the fluid discharge position defined on the bumper fascia of the front bumper 4 of the vehicle 1. In detail, between the upper end 4a and the lower end 4b of the front bumper 4, the fluid discharge position can be arbitrarily determined.

In addition, regardless of whether stagnation point 3 in FIG. 1 is positioned on the bumper fascia of front bumper 4, the fluid discharge position can be determined on the bumper fascia of front bumper 4. The fluid released from the bumper fascia of the front bumper 4 flows to a wide range of the surface of the automobile 1 as the main stream 2. Therefore, the air density of the mainstream 2 of a wide range can be reduced.

<Specific Configuration Example of Fluid Discharge Device>
Next, a specific configuration example of the fluid discharge device will be described. The fluid discharge device comprises a fluid discharge hole formed at the fluid discharge position. The fluid discharge device comprises a duct 5 formed on the bumper fascia of the front bumper 4 as a fluid discharge hole, as shown in FIG. The fluid discharge device discharges a fluid having a lower air density from the duct 5 compared to the outside air. The fluid discharge device comprises a pipe 7 whose one end is connected to the duct 5. The other end of the pipe 7 is connected to an exhaust port of an engine 8 which is an example of a drive source of the automobile 1 as shown in FIG. 4, for example. Exhaust gas exhausted from the engine 8 passes through the pipe 7 and is discharged from the duct 5 to the outside of the automobile 1. That is, the fluid discharge device discharges the exhaust gas discharged from the engine 8 as an example of the fluid having a lower air density than the outside air.

The exhaust gas exhausted from the engine 8 contains more water vapor than the atmosphere and is hotter than the atmosphere. For this reason, the molecular weight of the air of the mainstream 2 is lowered, and the temperature of the mainstream 2 is increased. Thus, the air density of the main flow 2 is reduced, so the air resistance of the automobile 1 can be reduced.

The driving source of the automobile 1 includes not only the engine 8 but also a fuel cell and a motor. That is, the automobile 1 includes a fuel cell vehicle (FCV), an electric vehicle (EV), and a hybrid car (HV, PHV) having two or more driving sources. The fuel cells include at least a solid oxide fuel cell (SOFC) and a polymer electrolyte fuel cell (PEFC). In addition, the engine 8, the fuel cell and the motor are also heat generating parts, and the air around them is hotter than the atmosphere. Further, the gas exhausted from the fuel cell contains a large amount of water vapor. Therefore, by collecting the high temperature gas around the drive source or the gas exhausted from the drive source and discharging it from the duct 5, the air density of the main stream 2 is reduced.

<Mechanism to reduce air resistance>
Next, the mechanism by which the air resistance of the automobile 1 is reduced by reducing the air density of the mainstream 2 will be described.

In general, the force received from the air by the automobile 1 during traveling is represented by forces in axial directions in front and rear, left and right, and upper and lower axes of the automobile 1 and moments around each axis, collectively called aerodynamic six component forces. Normally, the force received from the air by the automobile 1 while traveling is represented as non-dimensionalized, and in particular, the air resistance F which is a force in the back and forth direction is represented by an air resistance coefficient Cd represented by the following equation (1) . Here, ρ is the density of air in the outer region 43, A is the front projection area with respect to the traveling direction of the car 1, and V is the relative velocity of the car 1 with respect to the main flow.

Drag coefficient Cd is the product of the air dynamic pressure "pV ^2/2" and front projection area A, a value obtained by dividing the air resistance F. The air resistance coefficient Cd is an amount determined depending on the shape of the automobile 1, and affects the fuel consumption, the maximum speed, the acceleration performance and the like at the time of traveling. The air resistance F of an object such as the car 1 is dominated by pressure resistance when viewed as a whole of the car 1, and the frictional resistance that is a problem in aircraft is small in the car 1. Therefore, in order to reduce the air resistance F in the automobile 1, it is effective to focus on reducing the pressure resistance.

If Formula (1) is reviewed based on the above-mentioned attention, in a usual car design, the front projection area A is regarded as a parameter that can be dealt with by the design of the vehicle in order to reduce pressure resistance. On the other hand, since the mainstream air density ρ and the velocity V can be varied according to the traveling environment of the vehicle, they are not regarded as parameters that can be handled by the vehicle design.

However, without being bound by the above-mentioned existing concept, the inventor of the present invention has considered that the mainstream air density ρ can be a parameter that can be handled by the design of a vehicle in order to reduce pressure resistance. Then, focusing on the fact that the pressure resistance that occupies most of the air resistance F is proportional to the air density ρ of the main flow, it is possible to reduce the air resistance F by lowering the air density ρ of the main flow 2 I got the knowledge.

As shown in FIG. 5, the air of the main flow 2 is located away from the surface 20F of the vehicle body 20 and can not be heated directly. However, the fluid discharge device discharges the fluid having a lower air density relative to the outside air toward the outside of the vehicle 1 from the fluid discharge position defined on the surface of the vehicle 1 ahead in the traveling direction of the vehicle 1. The discharged fluid forms a main flow 2 located rearward in the direction of travel than the fluid discharge position. As a result, the air density ρ of the main flow 2 can be reduced, so the air resistance F of the automobile 1 can be reduced.

<Relationship between physical properties of fluid and density of fluid>
Next, the relationship between each physical property value of the fluid (air) discharged from the fluid discharge position and the air density will be described. FIG. 6A is a graph showing the relationship between the temperature of air and the air density. The higher the temperature of the air, the lower the density of the air. Therefore, by discharging the fluid having a temperature higher than that of the outside air, the temperature of the main flow 2 becomes high, and therefore the air density of the main flow 2 can be lowered.

The fluid having a temperature higher than the outside air includes the exhaust gas of the engine 8 shown in FIG. In addition to this, for example, as shown in FIG. 7, a blower 32 (including a compressor) sends air to the heat generating component 31 mounted on the automobile 1, and high temperature air heated by the heat generating component 31 is It may be collected and sent to the duct 5 through the pipe 7. The heat generating component 31 mounted on the automobile 1 includes an engine 8, a fuel cell, a radiator, a brake, a shock absorber, and a high power component (including a drive battery, a drive motor, and an inverter for driving the motor).

FIG. 6B is a graph showing the relationship between the molecular weight of air and the density of air. The lower the molecular weight of air, the lower the density of air. Therefore, by releasing the fluid having a molecular weight smaller than that of the outside air, the molecular weight of the main stream 2 is reduced, so that the air density of the main stream 2 can be lowered.

For example, the molecular weight of water (18.01528 g / mol) is smaller than the average molecular weight of air (28.966 g / mol). FIG. 6C is a graph showing the relationship between the partial pressure of water vapor in air and the density of air. The higher the water vapor partial pressure in the air, the lower the density of the air. Therefore, the molecular weight of the main stream 2 is reduced by releasing the fluid having a higher partial pressure of water vapor than the outside air, so the air density of the main stream 2 can be lowered.

A fluid having a partial pressure of water vapor higher than the outside air may be generated using the device shown in FIG. 8 in addition to the exhaust gas discharged from the engine 8 or the fuel cell. That is, the water discharged from the air conditioner 35 provided in the automobile 1 is collected in the container 33, a fine mist is generated using the ultrasonic transducer 34 disposed at the bottom of the container 33, and the mist is generated using the blower 32. Is sent from the piping 7 to the duct 5.

<Control of discharge flow rate of fluid>
The fluid discharge device can control the discharge flow rate of the fluid. For example, as the moving speed of the automobile 1 increases, the speed of the main stream 2 also increases, and the flow rate of the main stream 2 also increases. Therefore, the fluid discharge device changes the discharge flow rate of the fluid according to the moving speed of the automobile 1. Specifically, the fluid discharge device increases the discharge flow rate of the fluid as the moving speed of the automobile 1 increases.

For example, the fluid discharge device comprises a controller 61, as shown in FIG. 10C. The controller 61 controls the air discharge amount of the blower 32 based on the moving speed detected by the vehicle speed sensor 63. As the control pattern, any one of three control patterns 52a, 52b and 52c shown in the graph of FIG. 10A can be used.

Also, as the temperature of the fluid released by the fluid discharger is higher, the temperature of the main flow 2 can be raised by a smaller discharge flow rate. Therefore, the fluid discharge device changes the discharge flow rate of the fluid according to the temperature of the fluid to be discharged. Specifically, the fluid discharge device reduces the discharge flow rate of the fluid as the temperature of the discharged fluid is higher.

For example, as shown in FIG. 10C, the controller 61 controls the air discharge amount of the blower 32 based on the temperature of the fluid detected by the temperature sensor 62. Specifically, the controller 61 reduces the air discharge amount as the temperature of the fluid is higher. As the control pattern, any one of three control patterns 53a, 53b and 53c shown in the graph of FIG. 10B can be used.

In addition, as shown in FIG. 9, when the fluid which a fluid discharge | release apparatus discharge | releases is exhaust gas from the engine 8, the controller 61 controls the opening degree of the flow control valve 66. As shown in FIG. The flow rate control valve 66 adjusts the ratio of the flow rate discharged from the duct 5 to the flow rate sent to the exhaust manifold 65 out of the total flow rate of the exhaust gas discharged from the engine 8. When the opening degree of the flow control valve 66 is increased, the proportion of the flow released from the duct 5 is increased, and when the opening degree of the flow control valve 66 is decreased, the proportion of the flow discharged from the duct 5 is decreased.

<Coexistence of Cooling of Engine 8 and Reduction of Air Resistance>
In the vicinity of the stagnation point 3 or the front bumper 4 ahead of the traveling direction of the automobile 1, a radiator may be disposed to radiate the heat from the engine 8 to the outside air. However, if a fluid having a temperature higher than the ambient temperature is discharged from the fluid discharge position, a fluid having a temperature higher than the ambient temperature flows into the radiator, which may lower the cooling performance of the radiator.

Therefore, the fluid discharge device changes the opening degree of the radiator shutter that controls the air flow rate flowing into the radiator according to the discharge flow rate of the fluid discharged by the fluid discharge device. Thereby, the air resistance of the automobile 1 can be reduced without reducing the engine cooling performance of the radiator. Specifically, the opening degree of the radiator shutter is reduced as the discharge flow rate of the fluid discharged by the fluid discharge device increases. If the discharge flow rate of the fluid is small, it is difficult for fluid having a temperature higher than the ambient temperature to flow into the radiator, so even if the opening of the radiator shutter is large, the influence on the cooling performance of the radiator is small. If the discharge flow rate of the fluid is high, the opening degree of the radiator shutter is reduced to prevent the fluid having a temperature higher than the outside air temperature from flowing into the radiator. As a result, both the cooling of the engine 8 and the reduction of the air resistance of the automobile 1 can be achieved.

For example, as shown in FIGS. 11A and 11B, each of the radiator shutters 36 is rotatably supported by the fixed shaft 37, and one end of each radiator shutter 36 is connected to the movable link 38. The movable link 38 is vertically driven by the motor 60 and the gear 39. As a result, the opening degree of the radiator shutter 36 changes between the open state of the radiator shutter 36 shown in FIG. 11A and the closed state of the radiator shutter 36 shown in FIG. 11B. The controller 61 controls the opening degree of the radiator shutter 36 by controlling the motor 60 based on the discharge flow rate of the fluid released by the fluid discharge device detected by the flow rate sensor 64.

For example, the controller 61 controls the opening degree of the radiator shutter 36 based on the flow rate of the fluid detected by the flow rate sensor 64 using any of the control patterns 54a, 54b, 54c shown in FIG. 11D.

The control patterns 54a, 54b, 54c of FIG. 11D continuously change the opening degree of the radiator shutter 36. The controller 61 may change the opening degree of the radiator shutter 36 discontinuously. For example, as shown in FIG. 11C, the flow rate sensor 64 detects the flow rate of the fluid (S01), and determines whether the detected flow rate is equal to or greater than a predetermined threshold (predetermined value) (S03). If the threshold value is exceeded (YES in S03), the controller 61 controls the opening degree of the radiator shutter 36 to the closed state shown in FIG. 11B (S05). If it is less than the threshold (NO in S03), the controller 61 controls the opening degree of the radiator shutter 36 to the open state shown in FIG. 11A (S07).

As described above, according to the embodiment, the following effects can be obtained.

The vehicle 1 includes a fluid discharge device for discharging a fluid having a lower air density than the outside air from the fluid discharge position defined on the surface of the vehicle 1 ahead in the traveling direction of the vehicle 1 to the outside of the vehicle 1. As a result, the air density of the mainstream 2 in a wide range of the mainstream 2 around the automobile 1 is reduced, so that the air resistance of the automobile 1 can be reduced.

The fluid discharge position is a stagnation point 3 in the forward direction of travel. The stagnation point 3 is a point at which the pressure of the fluid is maximized, so the fluid released from the stagnation point 3 flows to the entire surface of the automobile 1. Therefore, the air density of the mainstream 2 of a wide range can be reduced. The outflow from stagnation point 3 is less likely to disturb the uniform flow streamline and has the least effect. Thus, the fluid released from stagnation point 3 can flow to the entire surface of car 1 and reduce the air resistance of car 1.

The fluid discharge position may be defined in the bumper fascia of the front bumper 4 of the automobile 1. The fluid released from the fluid discharge location on the bumper flows into the entire surface of the car 1. Therefore, the air density of the mainstream 2 of a wide range can be reduced.

The fluid released from the fluid discharge position is a fluid that is hotter than the ambient temperature. If the fluid is at a higher temperature than the outside air temperature, the temperature of the main stream 2 can be raised. Since the air density of the main flow 2 is lowered by the temperature rise of the main flow 2, the air resistance of the automobile 1 can be reduced.

The fluid released from the fluid discharge position is a fluid having a molecular weight smaller than that of the outside air. Since the molecular weight of the fluid is smaller than that of the outside air, the molecular weight of the main stream 2 air is reduced. Thus, the air density of the main flow 2 is reduced, so the air resistance of the automobile 1 can be reduced.

The fluid released from the fluid discharge position is a fluid in which the partial pressure of water vapor is higher than that of the outside air. Since the molecular weight of water is smaller than air, if the partial pressure of water vapor is higher than the outside air, the air density of mainstream 2 is reduced. Thus, the air resistance of the automobile 1 can be reduced.

The fluid discharged from the fluid discharge position is the exhaust gas discharged from the engine 8 provided in the automobile 1. The exhaust gas exhausted from the engine 8 contains more water vapor than the atmosphere, and has a high temperature. For this reason, the molecular weight of the main stream 2 air is reduced, and the temperature of the main stream 2 is increased. Thus, the air density of the main flow 2 is reduced, so the air resistance of the automobile 1 can be reduced.

The fluid discharge device changes the discharge flow rate of the fluid in accordance with the moving speed of the automobile 1. The fluid of the discharge flow rate necessary to reduce the air resistance of the automobile 1 can be discharged.

The fluid discharge device changes the discharge flow rate of the fluid according to the temperature of the fluid. The fluid of the discharge flow rate necessary to raise the temperature of the main stream 2 can be discharged.

The fluid discharge device changes the opening degree of the radiator shutter 36 provided in the automobile 1 in accordance with the discharge flow rate of the fluid. The air resistance of the automobile 1 can be reduced without reducing the engine cooling performance of the radiator. That is, both cooling of the engine and reduction of air resistance can be achieved.

Although the contents of the present invention have been described above according to the embodiments, the present invention is not limited to these descriptions, and it is obvious for those skilled in the art that various modifications and improvements are possible.

Although the above-mentioned embodiment mentioned and explained the case where a mobile was a car, the present invention is applicable to a mobile moving in the air besides a car. Examples of mobile objects include motorcycles, railways, aircrafts, rockets, etc. in addition to automobiles.

Although the above-mentioned embodiment described the case where the fluid discharged from the fluid discharge position satisfies any of the condition that the temperature is high, the molecular weight is low, or the partial pressure of water vapor is high compared to the outside air. Is not limited to this. The fluid may simultaneously satisfy two or more conditions arbitrarily selected from the above.

The fluid discharge device may also control the discharge flow rate of the fluid based on the combination of the moving speed of the automobile 1 and the temperature of the fluid.

1 Moving body 20F Surface 3 stagnation point (fluid discharge position)
4 bumper facia 8 engine 36 radiator shutter

Claims (10)

A movable body comprising a fluid discharge device for discharging a fluid having a lower air density relative to the outside air to the outside of the movable body from a fluid discharge position defined on the surface of the movable body in the forward traveling direction of the movable body. The mobile unit according to claim 1, wherein the fluid discharge position is a stagnation point ahead in the traveling direction. The movable body according to claim 1 or 2, wherein the fluid discharge position is defined in a bumper fascia of the movable body. The movable body according to any one of claims 1 to 3, wherein the fluid is a fluid having a temperature higher than the ambient temperature. The movable body according to any one of claims 1 to 4, wherein the fluid is a fluid having a molecular weight smaller than that of the ambient air. The movable body according to any one of claims 1 to 5, wherein the fluid is a fluid having a higher partial pressure of water vapor than ambient air. The movable body according to any one of claims 1 to 6, wherein the fluid is an exhaust gas exhausted from an engine provided in the movable body. The movable body according to any one of claims 1 to 7, wherein the fluid discharge device changes the discharge flow rate of the fluid according to the moving speed of the movable body. The movable body according to any one of claims 1 to 8, wherein the fluid discharge device changes the discharge flow rate of the fluid in accordance with the temperature of the fluid. The movable body according to any one of claims 1 to 9, wherein the fluid discharge device changes an opening degree of a radiator shutter provided in the movable body according to a discharge flow rate of the fluid.

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