Active airflow system of a high-performance battery-electric vehicle

Abstract

Air guidance system for the front of a battery-electric vehicle (1), comprising an air duct (3) for guiding ambient air to cool an electrical component of the vehicle (1), a first air inlet (5) to the air duct (3) and a second air inlet (7) to the air duct (3), wherein the first air inlet (5) to the air duct (3) is always open and the second air inlet (7) to the air duct (3) can be selectively closed and opened by a closing element (9), and comprising a control unit designed tothe closing element (9) to close the second air inlet (7) when the vehicle (1) is traveling at a speed greater than zero and when a predetermined speed-dependent limit value is undershot, and the closing element (9) to open the second air inlet (7) when the vehicle (1) is being loaded while stationary and when the vehicle (1) is traveling and exceeds the speed-dependent limit value, characterized in that the closing element (9) is designed as a splitter or diffuser.

Description

[0001] The invention relates to an air guidance system for the front of a battery-electric vehicle, as well as a vehicle with such an air guidance system.

[0002] Variable cooling air inlets for supplying a wheel brake device of a vehicle with cooling ambient air are known in the prior art.

[0003] EP 2 655 170 B1 relates to a motor vehicle with at least one cooling air duct formed in a floor plate of the same for supplying a wheel brake device of the motor vehicle with a cooling air stream, wherein the at least one cooling air duct is associated with an adjustable closing element in the form of a closing plate, which in turn depends on a sensed operating state of the wheel brake device and / or on the driving speed;the motor vehicle can be moved into an operating position in which the cooling air duct is at least partially open and the cooling air flow is permitted, and furthermore can be moved into an operating position in which the cooling air duct is closed and said cooling air flow is prevented, wherein, in addition, one or more further operating position(s) of the closure plate are provided, in which the same, forming a wheel spoiler, projects beyond the floor plate of the motor vehicle towards the roadway.

[0004] DE 20 2016 102 751 U1 also relates to an underbody air and heat management system for a motor vehicle, comprising: an aerodynamic fairing that includes a flap system which can be selectively moved between an open position and a closed position; a spoiler which can be selectively moved between a basic position and an extended position; and a control system for moving the flap system between the open position and the closed position and the spoiler between the basic position and the extended position.

[0005] DE 10 2019 133 502 B4 further relates to an air guide arrangement for a motor vehicle with at least one air guide element extending at least partially in the transverse direction of the motor vehicle in the front area of ​​the motor vehicle, which can be moved from a retracted rest position to an extended air guide position by at least one actuator, wherein the air guide element is movably connected to a body part of the motor vehicle via an extension arrangement, wherein the air guide element has an airfoil profile which generates dynamic lift when the speed increases in the extended state, wherein the extension arrangement extends through an opening in the front area in the extended state, wherein the opening is provided in the underbody element of the front area and is closed by a closing arrangement in the extended state of the extension arrangement, wherein the air guide element is fixedly connected to the extension arrangement.

[0006] German patent application DE 10 2018 114 499 A1 discloses a motor vehicle front end with a heat exchanger and associated fan. The cooling air flow has a forward-opening upper air inlet and an associated, motor-actuated upper flap assembly, and a downward-opening lower air inlet and a corresponding, motor-actuated lower flap assembly. Both air inlets are located upstream of the heat exchanger, and the air outlet is located downstream of the heat exchanger in the vehicle's underbody.

[0007] DE 10 2011 011 250 A1 describes a cooling system for a motor vehicle with a device for regulating an airflow to a radiator, wherein the device has at least one movable closing element that is movable between a closed position and an open position. It is provided that the closing element is movably mounted on a bumper cover, a cross member, or a sound-insulating engine enclosure.

[0008] In a high-performance battery-electric vehicle for road use, the cooling requirements differ drastically between driving and charging. Such a vehicle requires a maximum cooling airflow at constant speeds of 300 km / h, which differs significantly from the requirements during charging. To achieve the required aerodynamic and thermodynamic efficiency and to enable maximum range, air resistance must be reduced, and lift coefficients at the front axle, along with thermal management for the battery and an electrical distribution unit (EDU), must be dynamically adjusted.

[0009] The object of the invention is to improve the thermodynamic and aerodynamic properties of a cooling system for a high-performance battery-electric vehicle.

[0010] The invention is defined by the features of the independent claims. Advantageous further developments and embodiments are the subject of the dependent claims.

[0011] A first aspect of the invention relates to an air guidance system for the front of a battery-electric vehicle, comprising an air duct for guiding ambient air to cool an electrical component of the vehicle, a first air inlet to the air duct and a second air inlet to the air duct, wherein the first air inlet to the air duct is always open and the second air inlet to the air duct can be selectively closed and opened by a closing element, and comprising a control unit configured to actuate the closing element to close the second air inlet when the vehicle is traveling at a speed greater than zero and when a predetermined speed-dependent limit is undershot, and to actuate the closing element to open the second air inlet when the vehicle is charging while stationary and when the vehicle is traveling and the speed-dependent limit is exceeded.

[0012] The air guidance system is designed for the front of a high-performance battery-electric vehicle. Such a high-performance vehicle is expected to reach significantly higher speeds than conventional battery-electric vehicles. Since very high speeds are associated with very high air resistance, correspondingly high power output is required from the battery-electric vehicle's drive system for extended periods. The battery itself, as well as the power electronics, may require considerable cooling capacity, which can be achieved, at least in part, by circulating ambient air. Cooling capacity may also be required during battery charging to dissipate heat from components such as the battery itself. This enhances safety and extends the battery's lifespan.

[0013] On the other hand, at such high speeds, any change in the aerodynamic configuration is likely to have significant effects, which can influence cooling performance on the one hand, and the aerodynamic resistance of the vehicle and thus its efficiency on the other.

[0014] According to the invention, a control unit therefore checks the current state of the vehicle; if it is stationary and a vehicle battery is being charged, a second air inlet for the air duct is opened. While opening the second air inlet into the air duct can negatively affect the vehicle's efficiency when driving forward, this is irrelevant when the vehicle is stationary, and it can be ensured that a sufficiently large mass flow can be directed into the air duct, for example by means of a blower (or by utilizing convective effects).

[0015] Furthermore, at very high speeds, the control unit moves the closing element to an open position, thus opening the second air inlet for the air duct. At such high speeds, particularly high cooling capacities are required; the incoming air can therefore be at least partially introduced into the second air inlet of the air duct through the opening of the closing element.

[0016] At slower speeds, however, less cooling power is required, and the closing element can be used to close the second air intake for the air duct, thus increasing the vehicle's efficiency. The mass flow of air through the first air intake into the air duct is typically sufficient to ensure adequate cooling performance.

[0017] The movement of the locking element in response to a signal from the control unit can be achieved, for example, electrically, magnetically, hydraulically, pneumatically, or similarly. According to the invention, the locking element is also designed as a splitter or diffuser. For this purpose, the locking element preferably has a plate-like shape, which may have a curved surface. By deliberately positioning it at a certain angle, an aerodynamic angle of attack of the locking element can be achieved when the vehicle is moving forward, in order to generate aerodynamic lift or downforce, to deliberately direct the oncoming airflow, and to adjust the pressure conditions at the front of the vehicle.

[0018] For this purpose, the control unit continuously monitors the vehicle's status, as explained above. While the locking element opens automatically when the vehicle is stationary and charging, allowing access to the second air intake for cooling during charging, the locking element can be actively controlled while driving forward. A speed-dependent limit is set, which can take other parameters into account, such as the current battery temperature or the temperature of the power electronics. The limit can therefore be directly speed-dependent by default, or it can be indirectly and implicitly speed-dependent, for example, through temperature measurements at the battery or the power electronics. Thus, on particularly cold days, the limit may be set at higher speeds than on hot summer days.

[0019] However, it is to be expected that the limit value will be speed-dependent in any case. It is therefore advantageous to keep the closing element in the closed position for as long as possible in order to maximize the vehicle's aerodynamic efficiency.

[0020] To optimize aerodynamic performance, a cover element separating the first and second air inlets, as well as the closing element, can be designed with their aerodynamic qualities in mind. For example, the closing element and / or the cover element (individually or in combination) act as a diffuser. Preferably, the closing element and the cover element are designed in a plate-like form and, when installed in the vehicle, extend at least partially across the width of the vehicle.

[0021] Advantageous effects of the invention include the fact that, through adaptive control of the control unit, the aerodynamic configuration of the vehicle front can be adjusted depending on the vehicle's condition and the required (actual or expected) cooling capacity, in order to simultaneously minimize aerodynamic drag and meet requirements for aerodynamic lift. Driving stability can also be taken into account by appropriately selecting the switching points between the opening and closing of the second air intake by the closing element.

[0022] According to an advantageous embodiment, the locking element is plate-shaped with a curved surface.

[0023] According to a further advantageous embodiment, the first air inlet and the second air inlet are separated from each other by a plate-shaped cover element with a curved surface.

[0024] According to a further advantageous embodiment, the closing element is located at least partially below and at least partially behind the plate-shaped cover element in a position closing the second air inlet, wherein the closing element is located at least partially below the plate-shaped cover element in a position releasing the second air inlet and a gap separates the closing element and the plate-shaped cover element from each other.

[0025] The term "behind" refers to the regular airflow when the vehicle is moving forward. When the air guide system is installed in the vehicle, the incoming airflow typically first encounters the cover element and then the closing element. The gap between the cover element and the closing element can be deliberately shaped and sized to achieve the desired pressure conditions at the front of the vehicle.

[0026] According to another advantageous embodiment, a fan is arranged in the air duct.

[0027] The fan can be designed as a propeller, but due to its geometric constraints, it can also be described as a shrouded propeller. The fan's primary function is to draw in ambient air while the vehicle is stationary and charging its battery, and to pass this air through a heat exchanger. In this heat exchanger, heat from the battery or power electronics can be collected and dissipated by the mass flow through the air duct. The fan is therefore crucial when the vehicle is stationary and charging its battery, as the aerodynamic pressure that occurs at the front of the vehicle when it is moving forward is naturally absent. This pressure can be used for natural airflow, for example, into the first air intake.

[0028] According to another advantageous embodiment, a heat exchanger is arranged in the air duct.

[0029] According to a further advantageous embodiment, the air duct has an air outlet to the environment downstream of the heat exchanger. This air outlet allows the air heated by the heat exchanger, and with it the absorbed heat, to be advantageously discharged.

[0030] According to another advantageous embodiment, the closing element is designed as a splitter or diffuser.

[0031] Another aspect of the invention relates to a vehicle with an air guidance system as described above and below, wherein the first air inlet and the second air inlet are oriented towards an underbody of the vehicle and the air duct is oriented obliquely upwards.

[0032] According to a further advantageous embodiment, the closing element is aligned with an aerodynamic angle of attack to the main flow direction of the ambient air flowing towards the vehicle when the vehicle is moving forward.

[0033] Advantages and preferred further developments of the proposed vehicle result from an analogous and substantive transfer of the above statements made in connection with the proposed air guidance system.

[0034] Further advantages, features, and details will become apparent from the following description, in which – possibly with reference to the drawing – at least one embodiment is described in detail. Identical, similar, and / or functionally equivalent parts are identified by the same reference numerals.

[0035] They show: Fig. 1: A vehicle with an air guidance system according to an embodiment of the invention. Fig. 2: An air guidance system in a state when the vehicle is being charged while stationary, according to an embodiment of the invention. Fig. 3: The air duct system of the Fig. 2 in a state of slow forward movement of the vehicle. Fig. 4: The air duct system of the Fig. 2 in a state of rapid forward motion of the vehicle.

[0036] The representations in the figures are schematic and not to scale.

[0037] Fig. Figure 1 shows a vehicle 1, which has a sufficiently large battery to power the vehicle's electric drive for a sufficiently long period of time. The vehicle is a high-performance vehicle and reaches speeds of 300 km / h and more. At such high speeds, a considerable amount of cooling is required for electric drive components such as the battery. Therefore, an active air guidance system is arranged within the dashed circle marking the front of the vehicle 1, which operates in various states. Fig. 2 to Fig. 4 is described in more detail. Fig. 2 to Fig. Figure 4 therefore shows different adjustable states in a cross-section, which are explained below.

[0038] Fig. Figure 2 shows a cross-section of an air guidance system, in the same perspective as vehicle 1. Fig. 1 shown, for the front of the battery-electric vehicle 1 of the Fig. 1. When the vehicle 1 is moving forward, the airflow is expected to arrive from left to right in the plane of the image. The airflow can enter through a first air inlet 5 at any forward speed, particularly aided by dynamic pressure at the front of the vehicle 1. However, when the vehicle 1 is stationary, especially when its battery is charging, a fan 13 ensures a mass airflow through the first air inlet 5 to a heat exchanger 15 in the air duct 3, which has an outlet to the environment at its end. A plate-shaped cover element 11 separates the first air inlet 5 from a second air inlet 7 leading to the air duct 3. The cover element 11 is fixed and extends at least over a portion of the width at the front of the vehicle 1.Furthermore, a closing element 9 is provided which can be selectively moved by a signal from a control unit of the vehicle 1 either into a position opening the second air inlet 7, or into a position closing the second air inlet 7. In the . Fig. Figure 2 shows a state of the air duct system that is set by the control unit when the vehicle 1 is stationary and its battery is charging. The blower 13 generates an airflow through the air duct 3 and thus through the heat exchanger 15. This airflow can enter through both the first air inlet 5 and the second air inlet 7, as the closing element 9 is located with a gap below the cover element 11. Air can also flow through this gap. The airflows in the direction of flow upstream of the heat exchanger 15 are represented by dashed arrows, while the airflows downstream of the heat exchanger 15 and the fan 13 are indicated by dash-dotted lines.

[0039] Fig. Figure 3 shows the air guidance system of the Fig. 2 However, in a state where vehicle 1 is moving slowly forward. For efficiency reasons, the control unit pushes the closing element 9 behind the cover element 11 to close the second air inlet 7 in this speed range, so that no ambient air flows through the second air inlet 7 to the heat exchanger 15.

[0040] Fig. 4 shows the air guidance system of the Fig.2 in a further state of rapid forward travel of the vehicle 1. Here, the control unit again moves the closing element 9 into its open position, so that air flowing through the gap between the closing element 9 and the cover element 11 can also reach the heat exchanger 15 and absorb heat energy from it, which can be dissipated into the environment via the air duct 3. The blower 13 is of secondary importance here, since the incoming air through the first air inlet 5 already generates a corresponding flow, and the air flowing in by itself through the second air inlet 7 is in the same direction, whereby the blower 13 can additionally be used for intake.

[0041] Although the invention has been further illustrated and explained in detail by means of preferred embodiments, the invention is not limited by the disclosed examples, and other variations can be derived from them by a person skilled in the art without departing from the scope of protection of the invention. It is therefore clear that a multitude of possible variations exist. It is also clear that the embodiments mentioned as examples are truly only examples and are not to be understood in any way as limiting, for example, the scope of protection, the possible applications, or the configuration of the invention.Rather, the preceding description and the description of the figures enable the person skilled in the art to implement the exemplary embodiments in concrete terms, whereby the person skilled in the art, with knowledge of the disclosed inventive concept, can make various changes, for example with regard to the function or the arrangement of individual elements mentioned in an exemplary embodiment, without leaving the scope of protection defined by the claims and their legal equivalents, such as further explanations in the description. Reference symbol list 1 vehicle 3 air duct 5 first air intake 7 second air intake 9 Locking element 11 Cover element 13 Fan 15 heat exchangers

Claims

[1] Air guidance system for the front of a battery electric vehicle (1), comprising an air duct (3) for guiding ambient air for cooling an electrical component of the vehicle (1), a first air inlet (5) to the air duct (3) and a second air inlet (7) to the air duct (3), wherein the first air inlet (5) to the air duct (3) is always open and the second air inlet (7) to the air duct (3) can be selectively closed and opened by a closing element (9), and comprising a control unit designed toto control the closing element (9) to close the second air inlet (7) when the vehicle (1) is traveling at a speed greater than zero and when a predetermined speed-dependent limit value is undershot, and to control the closing element (9) to open the second air inlet (7) when the vehicle (1) is being loaded while stationary and when the vehicle (1) is traveling and when the speed-dependent limit value is exceeded, , characterized by , that the closing element (9) is designed as a splitter or diffuser.. [2] Air guidance system according to claim 1, wherein the closing element (9) is designed in a plate-like form with a curved surface. [3] Air guidance system according to one of the preceding claims, wherein the first air inlet (5) and the second air inlet (7) are separated from each other by a plate-shaped cover element (11) with a curved surface. [4] Air guidance system according to claim 3, wherein the closing element (9) in a position closing the second air inlet (7) is at least partially below and at least partially behind the plate-shaped cover element (11), wherein the closing element (9) in a position releasing the second air inlet (7) is at least partially below the plate-shaped cover element (11) and a gap separates the closing element (9) and the plate-shaped cover element (11) from each other. [5] Air guidance system according to one of the preceding claims, wherein a fan (13) is arranged in the air duct (3). [6] Air duct system according to one of the preceding claims, wherein a heat exchanger (15) is arranged in the air duct (3). [7] Air guidance system according to claim 6, wherein the air duct (3) has an air outlet to the environment in the direction of flow behind the heat exchanger (15). [8] Vehicle (1) with an air guidance system according to one of the preceding claims, wherein the first air inlet (5) and the second air inlet (7) are directed towards an underbody of the vehicle (1) and the air duct (3) is directed obliquely upwards. [9] Vehicle (1) according to claim 8, wherein the closing element (9) is aligned with an aerodynamic angle of attack to the main flow direction of the ambient air flowing towards the vehicle when the vehicle is moving forward.

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