DE102021209694A1 - Determining progressive contamination of an air filter - Google Patents

Abstract

In order to create a method (30, 40) for determining a filter loading condition of an air filter (11) of a ventilation system (10), in particular of a vehicle (100), which can be implemented with a minimum of technical effort, it is proposed that a new air filter (11 ) when replacing the filter in the ventilation system (10) and carrying out at least one reference measurement of measurement parameters, in particular of a fan motor (13), the measurement parameters being measured repeatedly, and a filter loading state (46) being determined based on the repeated measurements of the measurement parameters .

Description

The invention relates to a method for determining a filter loading condition of an air filter of a ventilation system. Furthermore, the invention relates to a vehicle with a ventilation system.

The increasing customer awareness of the air quality in the environment prompts the manufacturers of motor vehicles to optimize and improve filter technologies. As a rule, filters such as pollen filters or cabin filters show progressive degeneration as the filter load increases, which has a negative effect on the air exchange rate in the motor vehicle.

Filters in vehicles are currently replaced at fixed intervals, such as after a predefined period of time or a predefined number of kilometers. However, such rigid change intervals do not take into account the different usage behavior or usage environments of the customers.

If a filter is replaced too early, unnecessary costs and installation work are incurred. In addition, avoidable waste is generated in the process, which has a negative impact on the environment. If a filter is replaced too late, this procedure results in a deterioration in the air quality in the vehicle. In addition, the dehumidification of the interior deteriorates due to the reduced air mass flow when the filters are replaced late.

Methods are already known that use multiple sensors to measure a pressure difference caused by a filter. However, such solutions require additional sensors and evaluation units, which have an adverse effect on the cost efficiency of a vehicle.

The object of the invention is to create a method for detecting contamination of an air filter, which can be implemented with a minimum of technical effort.

This object is achieved by the features specified in claim 1. Further advantageous configurations of the invention are described in the dependent claims.

According to one aspect of the invention, a method for determining a filter loading state of an air filter of a ventilation system, in particular of a vehicle, is provided. In a first step, a new air filter is inserted into the ventilation system when the filter is replaced, and at least one reference measurement of measurement parameters, in particular of a fan motor, is carried out. In a further operation of the ventilation system, the measurement parameters are measured repeatedly. A filter loading condition is determined based on the repeated measurements of the measurement parameters.

A trend or a tendency of the measurement parameters can be determined by the repeated measurement of the measurement parameters. In particular, an increasing deviation from the reference measurement can be determined, which indicates a higher load on the fan motor, for example. This increased load on the fan motor results from a reduced volume of air that can flow through the air filter per unit of time due to increasing contamination. This method can be used in particular with actively controlled fans. Depending on the configuration, the current consumption, voltage and/or speed are measured for active regulation and can be used for an evaluation of the filter state or the filter loading state. As the filter becomes increasingly clogged, the speed, torque and thus also the power consumption of the blower or the electric motor that drives the blower change.

In the case of speed-controlled fans, the maximum achievable air mass flow of the fan is reduced as the filter loading condition increases while the speed remains the same, as a result of which the torque and thus also the power consumption of the fan are also increasingly reduced. An increasing filter loading condition can thereby be registered based on a decrease in the current demand of the blower.

Alternatively, voltage-controlled, commutated DC motors can be used to drive the fan. In such fans, a torque is impressed, and the speed of the fan increases with an increasing filter loading condition, since the torque is kept constant. Thus, an increasing filter loading condition can be registered based on an increase in the speed of the fan.

A control unit or an evaluation unit can evaluate the corresponding measurement parameters and, in particular, compare them with the reference measurement in order to implement an indication for a filter replacement. The reference measurement can preferably be carried out with a newly installed air filter in order to determine a state of the measurement parameters with an optimally functioning air filter. The reference measurement allows manufacturing tolerances or air filters from different manufacturers or different designs to be taken into account as a comparative value. The follow The measurements of the measurement parameters can thus be carried out independently of the installed air filter.

According to another aspect of the invention, a vehicle is provided. The vehicle is set up to carry out the method according to the invention. For this purpose, the vehicle has at least one ventilation system with a fan that can be driven by a fan motor in order to direct an air flow through an air filter of the ventilation system. Furthermore, a control unit is provided, which is connected directly or indirectly to the fan motor in a data-conducting manner.

Progressive contamination of the air filter can be determined by the method. Based on this determined contamination or the determined filter loading condition, a needs-based display for replacing the air filter can be implemented. In this way, external influences, such as dusty air or increased air pollution, and/or customer-specific behavior and the resulting degeneration of the air filter, for example in a motor vehicle, can be optimally taken into account. The indicator can signal a user to replace the air filter when the air filter actually needs to be replaced with a new air filter. Such signaling can take place acoustically, optically and/or visually, for example via the infotainment system.

The method according to the invention is not limited to use in vehicles and can in principle be used in mobile and stationary ventilation systems with at least one air filter and with at least one blower or fan motor. In addition, the method is not limited to filter systems for the air medium to be filtered and can be used for filter systems for all possible fluids, i.e. gases and/or liquids.

To determine the measurement parameters of the fan motor, the fan motor can preferably be designed as a speed-controlled or voltage-controlled motor or as a speed-controlled or voltage-controlled blower.

In order to carry out the reference measurement, preferably all disturbance variables, such as for example open doors or windows, can be eliminated. In addition, all vehicle doors, windows and flaps can be closed in order to generate a defined back pressure for the blower.

According to one exemplary embodiment, the measurement parameters are measured when the ventilation system is started, in a time interval of the ventilation system that is not in use and/or at predefined time intervals. In this case, the predefined time intervals can preferably fall at times when the blower or a vehicle is not being used. This measure means that the measurement parameters can only be determined when the ventilation system is not being used by any user. This can prevent the user from being adversely affected by reference measurements. In the case of an electric vehicle or a plug-in hybrid vehicle, for example, this can be a charging process. Depending on the design of the measurement process, the measurement parameters can also be measured during regular operation of the ventilation system at predefined time intervals.

The filter loading state can be determined particularly precisely if a motor current of the fan motor and/or an ambient pressure and/or a temperature and/or a relative humidity of an air mass flow through the air filter are measured or calculated as measurement parameters. In addition, a state or a water load or a retention of the condensate water in the fins of an interior evaporator can also be taken into account when determining the filter load state.

In an alternative or additional embodiment of the method, a motor power of the fan motor is measured or calculated as a measurement parameter.

According to a further embodiment, the measured measurement parameters are corrected by a determined ambient temperature, an ambient air pressure, a moisture content of an interior evaporator and/or by a relative humidity of the ambient air in the form of correction parameters. With this data, a "parasitic" change in the back pressure is calculated as a systematic error in order to measure the real filter loading condition. As a result, the measurement accuracy of the reference measurement can be increased.

The filter loading state can be determined or estimated in a variety of ways based on different methods if the filter loading state is determined by forming a relationship between the measured measurement parameters and the filter loading state using an algorithm, a simulation and/or a previously trained neural network. The use of a neural network to link the determined measurement parameters with the degree of filter loading enables the filter loading state to be determined even without knowledge of the analytical relationship between the measured variables and the filter loading.

According to a further exemplary embodiment, the measured measurement parameters are received by a control device via a vehicle-side bus system. As a result, the data already stored in the bus system can be received by the control unit as measurement parameters. Alternatively or additionally, the control unit can have direct access to the motor windings of the fan motor in order to be able to measure the measurement parameters directly on the corresponding electric motor.

The filter load status can be used to generate a message to a user of the ventilation system, in particular in the form of a warning message and/or error message, if a difference between the measured measurement parameters and the reference measurement exceeds a tolerance range.

According to a further aspect of the invention, a method for determining a filter loading state of a fluid filter or a screen is provided, in which a fluid filter or screen is replaced. A manual or automated reference measurement of operating parameters of an electric motor then takes place, which drives a fan, at least one compressor piston, at least one pump piston or at least one pump rotor. The operating parameters determined using the reference measurement can be normalized or error-compensated using correction values. In particular, thermal or barometric influences on the fluid filter or the sieve can be eliminated. In a further step, the operating parameters or measurement parameters are repeated in order to check a comparison with the operating parameters of the electric motor determined using the reference measurement. By changing the measured operating parameters over time, a statement can be made about the filter loading status. This can generate a recommendation for replacing or cleaning the fluid filter or the strainer.

• 1 eine schematische Seitenansicht eines Fahrzeugs mit einer Lüftungsanordnung gemäß einer Ausführungsform,
• 2 ein schematisches Ablaufdiagramm zum Veranschaulichen eines erfindungsgemäßen Verfahrens gemäß einer ersten Ausführungsform, und
• 3 ein schematisches Ablaufdiagramm zum Veranschaulichen eines erfindungsgemäßen Verfahrens gemäß einer ersten Ausführungsform.

Exemplary embodiments of the invention are explained in more detail below with reference to the drawings. Show it:

• 1 a schematic side view of a vehicle with a ventilation arrangement according to an embodiment,
• 2 a schematic flowchart to illustrate a method according to the invention according to a first embodiment, and
• 3 a schematic flowchart to illustrate a method according to the invention according to a first embodiment.

In the figures, the same structural elements each have the same reference numbers.

In the 1 1 is a schematic side view of a vehicle 100 with a ventilation system 10 according to an embodiment. The vehicle 100 is used to carry out a method for determining progressive contamination of an air filter 11 of the ventilation system 10. In the exemplary embodiment shown, the air filter 11 is arranged as a cabin air filter in a passenger vehicle.

The ventilation system 10 also has a radial fan 12 with a fan motor 13 . The fan motor 13 is designed as an electric motor and is connected to a control unit 20 via a bus system 21 in a data-conducting manner.

The fan motor 13 drives the radial fan 12 and thus generates an air flow, which is conducted through the air filter 11 into a vehicle interior 101 . The air flow is illustrated schematically by an arrow.

In the illustrated embodiment, the medium to be filtered is "air". Alternatively or additionally, liquids can also be filtered or cleaned. For this purpose, instead of the fan motor 13, an electric motor for driving or conveying a liquid and a filter for liquids are used instead of the air filter 11. The radial fan 12 can thus also be designed as a pump rotor, a compressor piston or as a pump piston for conveying fluids.

The 2 shows a schematic flowchart to illustrate a method 30 according to the invention according to a first embodiment. In particular, the method 30 illustrates a reference measurement for determining an initial system state or the initial filter loading state. The initial system state is influenced, for example, by wear and tear, leaks, filter make and the like. A precise determination of measured values of a reference measurement is explained in the first embodiment.

In a first step 31, a new air filter 11 is installed in vehicle 100 and then a reference measurement method 32 is initiated. The reference measurement 32 can be initiated manually by an owner of the vehicle 100 or by a workshop that performed the replacement of the air filter 11 . The reference measurement allows systematic errors and relative measurement errors to be reduced to a minimum.

Depending on the configuration of the method 30, optimal boundary conditions 33 can be set for the reference measurement. For example, an interior evaporator (not shown) can be dried and predefined settings of an air conditioning system of vehicle 100 can be made. The ventilation system of the vehicle 100 can be set to air recirculation mode and an air conditioning system can be deactivated. By activating the air recirculation mode, sources of error such as blocked supply air paths, for example due to snow or leaves, and blocked exhaust air paths, for example due to luggage in front of forced ventilation, can be eliminated.

The reference measurement can preferably be carried out at a maximum speed of the fan motor 13 . Due to the higher volume flows, the reaction of the pressure losses on the torque is improved. The measured values from the reference measurement can preferably be received by control unit 20 and stored in a memory (not shown). In particular, the repeated measurements can be related to the reference measurement, so that in such a configuration at least the result of the reference measurement must be stored in the memory.

An air distribution and flap positions can be transferred to predefined states. A position with the lowest flow resistance for the air flow is particularly advantageous. This can be, for example, a cold air path of an air conditioning system, air distribution in a so-called defog mode and the like. The air outlets used in defog mode cannot be closed or covered by users, thus avoiding user-specific errors.

In a further step 34 it can be ensured in the vehicle cabin or the vehicle interior 101 that all enclosing surfaces, such as windows, flaps, sliding roof and doors, are closed. In the case of open enclosing areas, a request to close them can be issued before initiating the reference measurement. In particular, repeat measurements and reference measurements cannot be carried out in this state, since the back pressure is not reproducible and superimposes the influence of the clogging filter.

For example, the motor current, the motor output, the ambient pressure level, the temperature of the air mass flow, the state of the interior evaporator and possibly the humidity of the air mass flow are determined as relevant reference measurements and stored in the memory of control unit 20 .

The reference measurement determines a large number of initial measured values that can be corrected using known influencing variables. In this case, the determination of correction variables 36 can take place in parallel with the implementation of the reference measurement 35 .

Based on the determined operating parameters or measurement parameters of the fan motor 13 and the correction values, the load value 39 of the fan motor 13 corrected to standard conditions can be calculated with the aid of an algorithm 37 or a previously learned neural network 38 . As a result, a particularly precise reference measurement can be carried out. The measured values initially determined by the reference measurement 35 are corrected by the correction variables 36 and replaced in the memory of the control device 20 .

In the 3 the inventive method 40 is illustrated according to a second embodiment. The method 40 is used to determine measurement parameters that are based on the corrected measurement values of the reference measurement 35, 39. In particular, a recurring repeat measurement is carried out to determine the state of the in 2 initially measured filter loading status.

In a step 41, a repeat measurement to determine the degree of loading of the air filter 11 is initiated. This measurement is used to determine operating parameters or measurement parameters that serve as a comparison with the measured values or the determined operating parameters of the reference measurement 39 .

The repeat measurement to determine the measurement parameters can be initiated manually by a customer or a workshop 42 or automatically 43 by the control unit 20 of the vehicle 100 . The measurement data determined can also be corrected using the known influencing variables, such as temperature and ambient pressure.

The measurements of the measurement parameters can be carried out automatically depending on a time interval or a distance driven when the vehicle 100 is empty or when the vehicle 100 is in a charging state or tank state.

In addition, the last driving data of the vehicle 100 can be queried 44 in order to check whether liquid has been deposited in an evaporator of the air conditioning system of the vehicle 100, since the water loading of the evaporator falsifies the measurement result. In the case of a wet evaporator, a drying process is preferably carried out. This can be analogous to setting the optimal operating conditions or boundary conditions 33 from the 2 take place.

In the further course of the procedure 40, analogously to in 2 described method 30 queries regarding open windows or doors 34 are performed. If the optimal boundary conditions have been set, the operating parameters 35 and the correction values 36 can be measured. The repeat measurement is optimally based on the existing state of the vehicle 100. Only if no suitable measurement conditions were found within a reasonable time, for example because the user leaves a sunroof raised, can a request be made to park the vehicle 100 completely closed or to carry out the measurement manually after it has taken place to start the shell closure.

Based on the determined operating parameters or measurement parameters of the fan motor 13 and the correction values, the load value corrected to standard conditions or the corrected operating parameters 39 of the fan motor 13 can be calculated using an algorithm 37 or a previously learned neural network 38 . The filter loading state is determined or estimated 45 on the basis of the corrected operating parameters or measurement parameters. An algorithm 37 or the learned or self-learning neural network 38 can be used for this purpose.

In a further step 46 of method 40, the corrected operating parameters can be checked for plausibility using the operating parameters last stored in control unit 20. Alternatively, the results can also be directly compared and checked for plausibility in the form of filter loading levels.

If the degree of filter loading deviates significantly from the normal state, the customer is informed of the progressive degeneration of the filter and an exchange of the air filter 11 is suggested.

In order to prevent customer discomfort, the recurring measurement of the operating parameters is preferably carried out outside of the operating and standby times of the vehicle 100, for example during unattended charging processes.

The degree of filter loading determined can also be stored in the memory of control unit 20 .

Reference List

100

vehicle

101

vehicle interior

10

ventilation system

11

air filter

12

centrifugal fan

13

fan motor

20

control unit

21

bus system

30

Procedure for making reference measurements

31

Replacing the air filter

32

Initiation of a reference measurement procedure

33

Setting of optimal boundary conditions

34

Query open windows, doors, flaps

35

Determination of operating parameters

36

Determination of correction variables

37

algorithm

38

neural network

39

Correcting measured values of operating parameters

40

Procedure for repeated measurement of operating parameters

41

Initiate repeat measurements

42

manual initiation of the measurement

43

automated initiation of the measurement

44

Querying driving data of the vehicle

45

Determining the filter loading status

46

check plausibility

Claims (9)

Method (30, 40) for determining a filter load status of an air filter (11) of a ventilation system (10), in particular of a vehicle (100), wherein a new air filter (11) is used in the ventilation system (10) when the filter is replaced and at least one reference measurement of Measurement parameters, in particular a fan motor (13), is carried out, the measurement parameters being measured repeatedly, and being based a filter loading condition (46) is determined on the repeated measurements of the measurement parameters. procedure after claim 1 , wherein the measurement parameters are measured when the ventilation system (10) is started, in a time interval that is not used by the ventilation system (10) and/or at predefined time intervals. procedure after claim 1 or 2 , wherein a motor power of the fan motor (13) is measured or calculated as a measurement parameter. Procedure according to one of Claims 1 - 3 , wherein a speed of the fan motor (13), a voltage of the fan motor (13), a motor current of the fan motor (13), an ambient pressure, a temperature and/or a relative humidity of an air mass flow through the air filter (11) are measured or calculated as measurement parameters become. Procedure according to one of Claims 1 until 4 , wherein the measured measurement parameters are corrected in the form of correction parameters (36) by a determined ambient temperature, an ambient air pressure, a moisture content of an interior evaporator and/or by a relative humidity of an ambient air. Procedure according to one of Claims 1 until 5 , wherein the filter loading state is determined by forming a relationship between the measured measurement parameters and the filter loading state using an algorithm (37), a simulation and/or a neural network (38) trained in advance. Procedure according to one of Claims 1 until 6 , wherein the measured measurement parameters are received by a control unit (20) via a vehicle-side bus system (21). Procedure according to one of Claims 1 until 7 , A warning message and/or error message being generated if a difference between the measured measurement parameters and the reference measurement exceeds a tolerance range. Vehicle (100) for carrying out the method (30, 40) according to one of the preceding claims, having at least one ventilation system (10) with a fan (12) which can be driven by a fan motor (13) in order to ensure an air flow through an air filter ( 11) of the ventilation system (10) and having a control device (20) which is directly or indirectly connected to the fan motor (13) in a data-conducting manner.

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