JP2019127042A - Air resistance reduction device - Google Patents

Abstract

To provide an air resistance reduction device which forms flow or a layer of the flow on a vehicle body surface to reduce air resistance of a vehicle and reduces power consumption needed for formation of the flow or the layer of the flow.SOLUTION: An air resistance reduction device 10 according to one embodiment of the technology of the disclosure includes: exhaust air lead-out means configured to lead out exhaust gas from an engine 24 of a vehicle 12 from an exhaust passage 48; and exhaust air supply means configured to supply the exhaust gas led out by the exhaust air lead-out means to an airflow separation inhibition portion at the exterior side of the vehicle.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to an air resistance reduction device for reducing air resistance in a vehicle.

  It is well known that the air resistance of a vehicle is greatly related to fuel consumption performance, acceleration performance, and the like. In order to reduce the air resistance of such a vehicle, various proposals have been made to improve the shape of the vehicle body or to provide the vehicle with a device for reducing the air resistance.

  Patent Document 1 discloses an example of an air resistance reduction device for a passenger car. In this air resistance reduction device, a movable wall is provided on the lower surface of a passenger car covered with a cover formed on a smooth surface, behind the position of about 500 mm from the front end of the vehicle body (at the position where a turbulent boundary layer occurs during traveling) Be The movable wall is accommodated in the concave portion of the cover, flush with the surface of the cover. Then, in a state where a slit formed inside the movable wall and a speaker as an exciter disposed further inside the slit are provided, the speaker is operated (allowing the speaker to oscillate) . Thus, in the air resistance reduction device of Patent Document 1, the movable wall is vibrated in the vibration mode (frequency, amplitude) according to the flexibility of the movable wall, the spacing and width of the slits, and the oscillation frequency of the vibrator, It tries to reduce the air resistance of the vehicle by shifting the separation point of the boundary layer of wind backward.

JP-A-9-118270

  By the way, in order to improve the air resistance in vehicles, it is known that it is effective to control exfoliation from the body surface of the air flow which flows along with the body surface of vehicles. One of the effective means for that purpose is to intentionally form a special flow or a layer of flow flowing along the surface of the vehicle body. For example, an electric pump can be used to form such a flow or flow layer.

  However, when the formation of such a flow or flow layer is performed by an electric pump in a vehicle, the operation of the electric pump depends on, for example, the remaining capacity of the on-board battery. In this case, the time when the flow or flow layer can be formed to reduce air resistance can be limited.

  The technique of the present disclosure aims to reduce the power consumption required for forming an air resistance reduction device that forms a flow or a flow layer on a vehicle body surface in order to reduce the air resistance of a vehicle.

In order to achieve the above object, the technology of the present disclosure
A device for reducing air resistance of a vehicle,
Exhaust exhaust means configured to guide exhaust gas from the power source of the vehicle from an exhaust passage of the power source;
There is provided an air resistance reducing device including an exhaust gas supply unit configured to supply the exhaust gas derived by the exhaust gas deriving unit to an air flow separation suppressing portion outside the vehicle.

  Preferably, the exhaust lead-out means is provided with flow control means provided to adjust the flow of exhaust gas to a lead-out passage communicating with the exhaust gas passage of the power source, and the operation of the flow control means. And control means for controlling.

  According to the air resistance reduction device according to the above technique of the present disclosure, since the above configuration is provided, exhaust gas can be derived from the exhaust passage and supplied to the air flow separation suppressing portion outside the vehicle. As described above, according to the air resistance reduction device, it is possible to form a flow or flow layer by the exhaust gas at the airflow separation suppression site while suppressing power consumption as compared to the case of using the electric pump. It is possible to reduce the air resistance.

It is a figure showing the front part of vehicles equipped with the drag reduction device concerning one embodiment in art of this indication. It is a schematic block diagram of the air resistance reduction apparatus of FIG. It is a control flowchart of the air resistance reduction apparatus of FIG.

  Hereinafter, embodiments according to the technology of the present disclosure will be described with reference to the accompanying drawings. The same parts (or configurations) are given the same reference numerals, and their names and functions are also the same. Therefore, detailed description about them will not be repeated.

  FIG. 1 shows a front portion of a truck 12 as a vehicle to which an air resistance reduction device 10 according to an embodiment of the present disclosure is applied, and FIG. 2 shows a schematic configuration of the air resistance reduction device 10.

  In the present embodiment, the air resistance reduction device 10 is applied to the front lower portion of the track 12. The air resistance reduction device 10 is configured to reduce the air resistance by supplying the exhaust gas of the power source to the outside as described in detail later. In FIG. 1, a plurality of openings 14 for supply of exhaust gas in the air resistance reduction device 10 are shown. The opening 14 supplies exhaust gas to a place where it is desired to suppress the separation of the traveling wind (airflow) flowing along the vehicle body surface when the truck 12 travels from the vehicle body surface (hereinafter referred to as an airflow separation suppression portion). It is configured to provide a flow of exhaust gas from the front side to the rear side of the vehicle. Here, the airflow separation suppressing portion is a region on the lower side (from the lower surface side of the vehicle body) of the bumper (which is a shock absorber for cushioning an impact or the like). Therefore, these openings 14 are provided below the bumper 12 a in front of the truck 12 so as to be aligned in the vehicle width direction. In addition, the location where the opening part 14 is provided is not limited to the lower side of the bumper 12a, and may be various airflow separation suppression sites or the upstream side (for example, the vehicle front side). As the air flow separation suppression portion, it is possible to define a portion where the traveling wind (air flow) flowing around the vehicle body may peel or the periphery thereof. However, the airflow separation inhibiting part can be determined by experiment. For example, the opening 14 is formed in the front pillar (A pillar) 12b, the holding portion of the side mirror 12c, the upper wall 12d of the cab (driver's cab, vehicle compartment), and the upper end 12e on the front side of the frame (carrier) behind the cab. May be provided. In addition, although the opening part 14 is a slit here, this does not limit the shape of the opening part 14, for example, may be made into a circular hole. For example, instead of the plurality of openings 14, a single elongated opening extending in the vehicle width direction may be provided.

  The air resistance reduction device 10 is provided with an exhaust lead-out means configured to lead an exhaust gas from an internal combustion engine (hereinafter referred to as an engine) 24 as a power source of the truck 12. And an exhaust supply means (with the opening 14 described above) configured to supply the In the following, first, the configuration of the engine 24 will be described, and exhaust emission and supply therefrom will be described.

  An engine 24 shown in FIG. 2 which is a power source of the truck 12 is a diesel engine here. However, the engine 24 may be various engines, for example a gasoline engine. The engine 24 burns a mixture of fuel and air inside the combustion chamber 26 and reciprocates the piston 30 in the cylinder 28 a of the cylinder block 28 to generate power. The intake port of the combustion chamber 26 is connected to the intake manifold 32, and the exhaust port of the combustion chamber 26 is connected to the exhaust manifold 34. The cylinder head of the engine 24 is provided with an intake valve Vi for opening and closing the intake port, an exhaust valve Ve for opening and closing the exhaust port, and a fuel injection valve 36 for each combustion chamber 26. The intake manifold 32 is connected to an intake pipe 38, and the intake pipe 38 is connected to an air intake (not shown) via an air cleaner 40. Further, a throttle valve 42 is incorporated on the downstream side of the air cleaner 40. On the other hand, the exhaust manifold 34 is connected to the exhaust pipe 44. The exhaust pipe 44 is connected to an exhaust purification device 46. The exhaust gas discharged from the combustion chamber at the time of opening the exhaust port is subjected to exhaust gas purification processing by the exhaust gas purification device 46, and thereafter an exhaust passage partitioned by the exhaust pipe 50 connected downstream of the exhaust gas purification device 46 It is discharged outside the car via 48. The exhaust gas purification device 46 can have various configurations, for example, a diesel particulate filter (DPF) for removing and burning particulate matter (PM), a selective reduction catalyst (SCR catalyst), and the like. A combined configuration can be provided.

  A valve device 52 as a flow control means in the exhaust gas lead-out means is incorporated in the exhaust pipe 50 which defines the exhaust passage 48 downstream of the exhaust gas purification device 46. An outlet pipe 56 is connected to the exhaust pipe 50 via the valve device 52. The outlet pipe 56 defines an outlet passage 54 for extracting the exhaust gas from the exhaust passage 48. The valve device 52 is not limited to the configuration shown in FIG. 2 and can have various configurations such as a butterfly type valve, a shutter type valve, and a pivot type valve. The valve device 52 includes a valve body 52a, seating portions 52b and 52c on which the valve body 52a is seated, and an actuator 58 for moving the valve body 52a. The drive control of the actuator 58 is performed by the control device 70 described later, whereby the valve device 52 (the valve body 52a thereof) is operated. In the valve device 52, almost all of the exhaust gas that has passed through the exhaust purification device 46 (the valve main body 52a is in a state indicated by a broken line in FIG. 2) passes through the exhaust passage 48 '(on the downstream side of the valve device 52). And a state in which almost all of the exhaust gas that has passed through the exhaust purification device 46 (the state indicated by the solid line in FIG. 2 is the valve main body 52a) flows through the exhaust passage 54 (complete derivation). It is designed to be able to take any state in between. In the initial state, the valve device 52 is designed to be in the completely discharged state, but may be designed to be in the completely derived state or an intermediate state thereof.

  A distribution unit 60 is provided on the downstream side of the outlet pipe 56 that defines the outlet passage 54. Here, the distribution unit 60 is provided with the plurality of openings 14 described above. Therefore, the exhaust gas led out from the exhaust passage 48 through the valve device 52 to the outlet passage 54 can be supplied from the plurality of openings 14 to the airflow separation suppressing portion outside the track 12.

  In the present embodiment, the exhaust gas discharge means is configured to include the valve device 52 and (part of) the control device 70. Further, the exhaust gas supply means is configured to include the outlet passage 54 and the opening portion 14.

  The control device 70 having the function of controlling the operation of the actuator 58 of the valve device 52 includes an arithmetic device (for example, CPU), a storage device (for example, ROM, RAM), an input / output port, etc. Have. Various sensors are connected to the control device 70 through an input port, and for example, an engine rotational speed sensor 72 for detecting an engine rotational speed, an engine load sensor 74 for detecting an engine load, and a vehicle speed A vehicle speed sensor 76 for driving the brake and a brake switch 78 which is turned on from the off state when the brake pedal is depressed are connected. The engine rotational speed sensor 72 may be a crank angle sensor for detecting the rotational angle of a crankshaft to which the piston 30 is connected via a connecting rod. The engine load sensor 74 may be an accelerator opening degree sensor for detecting an operation amount (accelerator opening degree) of an accelerator pedal operated by a driver, an intake pressure sensor for detecting a pressure in an intake passage, or the like. Then, the control device 70 controls the operation of the fuel injection valve 36 and the throttle valve 42 according to the programs and data stored in advance according to the outputs (inputs) from these sensors, as well as the valve device 52 (actuator of the valve device 52). Control the operation of 58). That is, a part of the control device 70 has a function as control means for controlling the operation of the actuator 58 of the valve device 52 as the flow control means.

  Here, control of the valve device 52 in the air resistance reduction device 10 by the control device 70 will be described based on the flowchart of FIG. 3. First, in step S301, the control device 70 determines whether the vehicle speed is equal to or higher than a predetermined speed. The vehicle speed is detected (acquired) based on the output of the vehicle speed sensor 76. The predetermined speed is herein defined as an index for determining whether or not the vehicle is in a traveling state where the reduction effect of the air resistance is desired. Then, since the vehicle speed is equal to or higher than the predetermined speed, when an affirmative determination is made in step S301, the process proceeds to step S303.

  In step S303, it is determined whether or not the operating state is a predetermined operating state. The operating state to be determined here is the engine operating state, and is detected (acquired) based on the output of the engine rotational speed sensor 72 and the output of the engine load sensor 74. Here, the predetermined operation state is defined as an operation state in a low load region. The predetermined operating state is not limited to the operating state in the low load region, and may be determined in consideration of, for example, the exhaust pressure, the pressure in the lead-out passage, and the like. The operating condition to be determined may be understood as the required torque based on the output of the engine rotational speed sensor 72 and the output of the engine load sensor 74. Then, since the driving state is a predetermined driving state, when the positive determination is made in step S303, the process proceeds to step S305.

  In step S305, it is determined whether or not there is a braking operation. The presence or absence of the braking operation is determined according to the ON-OFF state of the brake switch 78. When the brake switch 78 is in the OFF state because the brake pedal 78 is not depressed, an affirmative determination is made in step S305. Note that one of the reasons why the determination in step S305 is performed is that there is no particular need to reduce the air resistance when the brake pedal is depressed.

  When an affirmative determination is made in step S305, the supply flag is turned on in step S307. In the initial state, the supply flag is in the OFF state. When the supply flag is turned ON, the control device 70 acquires the valve main body 52a of the valve device 52 according to the operation state acquired at step S303 or newly acquired at that time according to the program or data stored in advance. The target opening (target position) is calculated. However, the target opening degree calculated at this time is an opening degree at which at least a part of the exhaust gas can flow to the lead-out passage 54. The target opening degree of the valve main body 52a may be further calculated based on the vehicle speed and the like. Then, the control device 70 controls the operation of the actuator 58 of the valve device 52 so that the opening degree of the valve body 52a becomes the calculated target opening degree. When the supply flag is turned ON, the valve body 52a may be moved to a predetermined opening degree (position). As a result, the exhaust gas is led from the exhaust passage 48 to the lead-out passage 54, and the portion where it is desired to suppress the separation of the airflow that flows along the outside of the truck 12, particularly along the surface of the vehicle body via the lead-out passage 54 and the opening 14, is separated. It can be supplied to the suppression site. Note that the routine ends by passing through step S307, and step S301 of the next routine is executed.

  On the other hand, since the vehicle speed is not equal to or higher than the predetermined speed, a negative determination is made in step S301. A negative determination is made in step S303 because the operating state of the engine as the power source is not the predetermined operating state. If a negative determination is made in S305, the aforementioned supply flag is turned OFF in step S309. When the supply flag is turned OFF, the controller 70 controls the operation of the actuator 58 so that the valve body 52a of the valve device 52 is in the state shown by the broken line in FIG. As a result, substantially all of the exhaust gas having passed through the exhaust gas purification device 46 is discharged out of the vehicle through the exhaust passage 48 'without passing through the opening portion 14. Note that the routine ends by passing through step S309, and step S301 of the next routine is executed.

  As described above, according to the air resistance reduction device 10 of the present embodiment, the exhaust gas of the engine 24 (in particular, the exhaust gas purified by the exhaust gas purification device 46) is drawn from the exhaust passage and through the opening portion 14 It can be supplied to the outside of the vehicle to form a flow or flow layer (mainly exhaust gas) on the air flow separation suppressing portion on the vehicle body surface. Therefore, according to the air resistance reduction device 10, it is possible to suppress the separation of the traveling wind (air flow) from the surface of the vehicle, particularly when the truck 12 travels, thereby reducing the air resistance.

  In addition, this indication is not limited to the above-mentioned embodiment, In the range which does not deviate from the meaning of this indication, it can change suitably and can be carried out. For example, the power source is not limited to being an engine, and may be a fuel cell system. When the power source is a fuel cell system, the water vapor and the like discharged from the fuel cell correspond to the “exhaust gas” (from the power source) in the technology of the present disclosure. Also, the opening 14 is not limited to being configured as a simple outlet, and may be shaped so as to be tapered from the inside to the outside of the vehicle in order to further stabilize the flow direction of the exhaust gas. A nozzle may be provided in the opening 14. Also, the vehicle to which the technology of the present disclosure is applied is not limited to a truck, and the technology of the present disclosure may be applied to various vehicles.

  Further, in the above embodiment, the valve device 52 is incorporated in the exhaust passage 48, but may be provided in the outlet passage 54 communicating with the exhaust passage 48. Furthermore, in the above-described embodiment, when exhaust gas is supplied to the outside of the vehicle through the opening 14 to reduce the air resistance of the vehicle, it is when all determinations in steps S301 to S305 are affirmative. However, the technique of the present disclosure is not limited to this, and for example, when the condition of step S301 is satisfied (when an affirmative determination is made in step S301), or when the condition of step S303 is satisfied (step S303). The supply flag may be turned ON whenever an affirmative determination is made).

10 Air resistance reduction device 12 Truck (vehicle)
14 Opening 24 Engine 26 Combustion chamber 28 Cylinder block 30 Piston 32 Intake manifold 34 Exhaust manifold 36 Fuel injection valve 40 Air cleaner 42 Throttle valve 44, 50 Exhaust pipe 46 Exhaust purification device 48, 48 'Exhaust passage 52 Valve device (flow control means) )
54 Derivation passage 56 Derivation pipe 58 Actuator 60 Distribution unit 70 Control device 72 Engine rotation speed sensor 74 Engine load sensor 76 Vehicle speed sensor 78 Brake switch

Claims (2)

A device for reducing air resistance of a vehicle,
Exhaust exhaust means configured to guide exhaust gas from the power source of the vehicle from an exhaust passage of the power source;
An air resistance reduction device, comprising: an exhaust gas supply unit configured to supply the exhaust gas derived by the exhaust gas deriving unit to an air flow separation suppressing portion outside the vehicle.   The exhaust lead-out means is provided with flow control means provided to adjust the flow of exhaust gas to a lead-out passage communicating with the exhaust gas passage of the power source, and control for controlling the operation of the flow control means. Means for reducing air resistance according to claim 1.

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