DE102022200083A1 - Method for controlling a thermal management system and vehicle comprising a thermal management system - Google Patents

Abstract

A method (100) for controlling a thermal management system of a vehicle is proposed, which comprises controlling (101) the thermal management system depending on a current wind influence and/or a current and/or future rain influence on the vehicle.

Description

The present invention relates to a method for controlling a thermal management system of a vehicle and a vehicle comprising a thermal management system according to the independent claims.

Thermal management systems for vehicles are known from the prior art, although weather influences on the vehicle are not taken into account when controlling them.

The object of the present invention is to make a method for controlling a thermal management system more efficient. In detail, the power used for the thermal management system is to be reduced.

The aforementioned object is achieved by a method for controlling a thermal management system of a vehicle, which includes controlling the thermal management system as a function of a current wind influence and/or a current and/or future rain influence on the vehicle.

A vehicle is to be understood in particular as a motor vehicle or a commercial vehicle. This can be a vehicle for rail transport, land transport or for aviation.

A wind influence is to be understood in particular as meaning a wind speed and/or a wind direction in the immediate vicinity of the vehicle. The wind influence can be positive (tail wind) or negative (front wind) in the longitudinal direction of the vehicle. A rain effect is to be understood primarily as a quantity of rain and/or quantity of spray that acts on the vehicle.

The method can include determining the current wind influence. For this purpose, the method primarily includes determining a current drive power and a reference power, with a rolling resistance, a gradient resistance, an acceleration resistance and an air resistance based on the driving speed being taken into account when determining the reference power. Overall air resistance acts on the vehicle, with part resulting from the driving speed and another part from the influence of the wind. The reference performance does not take into account air resistance based on wind influence.

The method also preferably includes a comparison of the current drive power, which is affected by the air resistance based on the wind influence, and the reference power, so that the wind influence can be determined here. In other words, the wind influence is therefore situational, that is determined from the current situation.

$$\text{F}\left(\text{Luftwiderstand}\right)=\text{F}\left(\text{Fahrgeschwindigkeit}\right)+/-\text{F}\left(\text{Windeinfluss}\right)$$

$$\begin{array}{l}\text{F}\left(\text{Windeinfluss}\right)=\text{F}\left(\text{Antrieb}\right)-\text{F}\left(\text{Fahrgeschwindigkeit}\right)-\text{F}\left(\text{Rollwiderstand}\right)-\\ \text{F}\left(\text{Steigungswiderstand}\right)-\text{F}\left(\text{Beschleuningswiderstand}\right)\end{array}$$

The current drive power is known in every situation. It is converted into a driving force. This is equal to a force based on drag, a force based on rolling resistance, a force based on grade resistance, and a force based on acceleration resistance. The rolling resistance in the vehicle can be calculated based on given data. The gradient resistance can also be determined, for example, by means of an inclination sensor, for example a position sensor of the headlight range control. The acceleration resistance can also be calculated from known vehicle data. The forces resulting from the resistances mentioned above can thus be determined. As already indicated above, the force based on air resistance is composed of a force based on the driving speed and the resulting resistance and a force based on the wind speed and the corresponding resistance. The following therefore applies: $$\begin{array}{l}\text{f}\left(\text{drive}\right)=\text{f}\left(\text{air resistance}\right)+\text{f}\left(\text{rolling resistance}\right)+\text{f}\left(\text{incline resistance}\right)+\\ \text{f}\left(\text{acceleration resistance}\right)\end{array}$$

$$\text{f}\left(\text{air resistance}\right)=\text{f}\left(\text{driving speed}\right)+/-\text{f}\left(\text{wind influence}\right)$$

$$\begin{array}{l}\text{f}\left(\text{wind influence}\right)=\text{f}\left(\text{drive}\right)-\text{f}\left(\text{driving speed}\right)-\text{f}\left(\text{rolling resistance}\right)-\\ \text{f}\left(\text{incline resistance}\right)-\text{f}\left(\text{acceleration resistance}\right)\end{array}$$

However, the force based on the influence of the wind is also dependent on the air speed, namely the force $$\text{f}\left(\text{wind influence}\right)={\text{c}}_{\text{w}}\times \text{A}\left({\text{Air Density*Air Velocity}}^2\right)/2.$$

_cw is the drag coefficient, while A is the frontal area of the vehicle.

The air speed which causes the wind influence can thus be determined from the force with regard to the wind influence. In other words, a drive power of the vehicle, as described above, can be determined from the different factors, while at the same time a reference power that is dependent on the operating point can be determined that does not take into account the influence of the wind. By comparing the two, the influence of the wind and thus the air speed in detail can be determined. From this, the wind speed in the vicinity of the vehicle can be determined, since the following applies: $$\text{air speed}=\text{driving speed}+-\text{Wind speed in vehicle environment}$$

Furthermore, the wind direction can be determined, for example, by retrieving weather data and/or by a sensor.

The method may further include determining a rain effect based on a rain sensor of the vehicle. In such a case, the influence of rain is again determined according to the situation. Furthermore, a future rain influence can be determined on the basis of weather data, in particular weather data from external sources. Above all, a forecast rain situation at the location, in particular also at the future location, of the vehicle is determined. The weather data can, for example, be digital weather data, for example from a weather service. The weather data can preferably be retrieved online by means of the method.

In particular, at least one cooling fan, preferably its speed, and/or at least one switchable cooling air inlet of the cooling fan, preferably its degree of opening, is controlled by means of the controller. The energy expenditure for the thermal management can be reduced since, for example, an additional air quantity, which is based on the wind influence, can be taken into account when the cooling fan and/or the cooling air inlet is activated. In other words, the air mass flow is dependent on the air speed, ie the driving speed and the wind speed, and can therefore be controlled more effectively by taking into account the influence of the wind.

With regard to the influence of rain, preferably the current influence of rain, the method can include, for example, opening the cooling air inlet when a threshold value with regard to the amount of rain and/or the amount of spray is exceeded. It can thus rain and / or spray can be directed to a heat exchanger of the vehicle to optimize the heat transfer of the heat exchanger. The heat transfer at the heat exchanger is better when it is wetted with water than when it is not wetted. The result is a reduction in the power required for heat transport, namely a power of the cooling fan can be reduced and the cooling potential acting on the heat exchanger is increased.

The thermal management system can be controlled predictively based on the future influence of rain. The vehicle can have an electric drive, for example, and the cooling fan and/or the switchable cooling air inlet can be controlled with regard to preconditioning when approaching a charging station of the vehicle. A reduction in the power required for the preconditioning is also possible in this way. The result of a preconditioning can also be optimized, for example a higher charging capacity can be achieved since the battery is in the optimum temperature window more quickly. This increases efficiency through more targeted preconditioning of the cooling air for the thermal management system.

The inlet of cooling air can preferably be controlled depending on the influence of the wind, in particular the wind speed and/or the wind direction. For example, if the air speed and/or the wind speed exceeds a predefined threshold, the cooling air inlet can basically be kept open, in other words no longer closed, since the downforce on the rear axle of the vehicle is then influenced, which has a negative effect on driving safety. In the prior art, only the driving speed is used as a threshold value for this purpose. By taking the actual air speed and/or wind speed into account, the control can be significantly optimized and made usable in a broader range depending on the driving speed. Furthermore, the functional safety is increased since the rear downforce is influenced.

In particular, the method is designed to regulate the thermal management system.

In a further aspect, the invention comprises a vehicle comprising a thermal management system, the vehicle comprising a control unit for controlling a thermal management system, which is designed to control as a function of a current wind influence and/or a current and/or future rain influence. In particular, the thermal management system is designed to carry out a method described above.

• 1 ein Verfahrensschema eines erfindungsgemäßen Verfahrens.

It shows purely schematically

• 1 a process diagram of a process according to the invention.

1 shows a process diagram of a method 100 according to the invention, which includes a controller 101 of a thermal management system of a vehicle depending on a current wind influence and/or a current and/or future rain influence on the vehicle. In detail, a cooling fan and/or a switchable cooling air inlet of the cooling fan is controlled 102. The method 100 includes in particular the determination 103 of the current wind influence and the determination 106 of the current rain influence on the basis of a rain sensor and/or the determination 107 of a future rain influence on the basis of weather data. When determining the current wind influence, a drive power and a reference power of the vehicle are determined 104, with the determination of the reference power taking into account a current drive power, rolling resistance, gradient resistance, acceleration resistance and air resistance based on the driving speed 105. From the reference of the Drive power and the reference power, the wind influence can be determined.

Reference List

100

Process for controlling a thermal management system

101

Control of the thermal management system as a function of a current wind influence and/or a current and/or future rain influence on the vehicle

102

Control of a cooling fan and/or a switchable cooling air inlet of the cooling fan

103

Determining the current wind influence

104

Determining a drive power and a reference power

105

Taking into account a current drive power, a rolling resistance, a gradient resistance, an acceleration resistance and an air resistance based on the driving speed

106

Determination of the current rain influence based on a rain sensor

107

Determination of a future rain influence based on weather data

Claims (9)

Method (100) for controlling a thermal management system of a vehicle, characterized in that the method (100) comprises controlling (101) the thermal management system depending on a current wind influence and/or a current and/or future rain influence on the vehicle. Method (100) according to claim 1 , characterized in that a wind influence is to be understood as meaning a wind speed and/or a wind direction. Method (100) according to claim 1 or 2 , characterized in that a rain effect is to be understood as a quantity of rain and/or quantity of spray. Method (100) according to one of the preceding claims, characterized in that the method (100) includes determining (103) the current wind influence, the method (100) for this purpose including determining (104) a current drive power and a reference power of the vehicle . Method (100) according to claim 4 , characterized in that when determining the reference performance, a rolling resistance, a gradient resistance, an acceleration resistance and an air resistance based on the driving speed are taken into account (105). Method (100) according to one of the preceding claims, characterized in that the method (100) comprises determining (106) the current influence of rain on the basis of a rain sensor of the vehicle. Method (100) according to one of the preceding claims, characterized in that the method (100) comprises determining (107) a future influence of rain on the basis of weather data. Method (100) according to one of the preceding claims, characterized in that at least one cooling fan and/or at least one switchable cooling air inlet of the cooling fan are controlled (102) by means of the method (100). Vehicle comprising a thermal management system, the vehicle comprising a control unit for controlling a thermal management system, characterized in that the control unit for controlling the thermal management system is dependent on a current wind influence and/or a current and/or future rain influence on the vehicle.

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