Replacement of a fine dust filter in a vehicle cooling module as needed

Abstract

System for creating a diagnosis of the loading state of an air-flowed fine dust filter (1) of a cooling module (3) of a vehicle with separated fine dust, comprising a computing unit (5) configured to detect currently prevailing boundary conditions of the operation of the fine dust filter (1) and to repeatedly determine the current cooling capacity of the cooling module (3) at various times with boundary conditions within predefined similarity limits, and to determine a loading state of the fine dust filter (1) by comparing the current cooling capacity of the cooling module (3) with model values ​​of the cooling capacity of the cooling module (3) consistent with the current boundary conditions, and to transmit a command to an output unit to issue a warning about the loading state of the fine dust filter (1) if a predefined limit value is exceeded by the determined loading state, characterized in thatthat the computing unit (5) is designed to detect whether the vehicle's battery is being charged and to select the different times distributed across different charging processes.

Description

[0001] The invention relates to a system for making a diagnosis about the loading state of an air-flow particulate filter of a cooling module of a vehicle with separated particulate matter, as well as to a vehicle with such a system.

[0002] Particulate matter filters are typically used to reduce particulate matter emissions from vehicles. Such particulate matter filters can also be installed in the front module (cooling module) of the vehicle, where they are permeated with air. The filter is integrated into the air path, and the air flowing through the cooling module also flows through the particulate matter filter. While a particulate matter filter typically creates a certain pressure loss even when new, this pressure loss increases as the particulate matter load increases. This resistance to airflow has a significant impact on the function of such a cooling module and its thermal management system. For example, to maintain a constant temperature in the cabin and various drive components, the pressure loss must be increasingly compensated for as the load increases.A heat sink in the front module can, for example, be kept at its original level (an unloaded particulate matter filter) by increasing the power consumption of an electric suction fan, a refrigerant compressor, or water pumps. Depending on the load, however, the cooling module can reach its limits, i.e. all components are operating at their maximum performance and further compensation for the pressure loss can no longer take place. The frequency of these constellations increases with the increasing load of the particulate matter filter with separated particulate matter. The negative influence of the particulate matter filter thus becomes noticeable for the user and can, under certain circumstances, reduce the service life of the vehicle components to be cooled. The increased power consumption of the components of the thermal system results in more electrical energy being consumed, which in turn influences certification-relevant variables such as the range of an electric vehicle.

[0003] The longest possible interval for replacing the particulate matter filter prevents unnecessarily early disposal. At the same time, there is a risk that a higher than expected load on the particulate matter filter could lead to insufficient cooling performance in the aforementioned case. Further complicating matters is the fact that the need for a filter change depends heavily on the vehicle's location and the local particulate matter concentration. Therefore, replacing the particulate matter filter only when necessary is ideal—that is, when a certain level of particulate matter is present.

[0004] State-of-the-art solutions for monitoring the loading status of a particulate matter filter are known. These are often based on the direct measurement of the pressure drop along a flow path through the particulate matter filter.

[0005] DE 10 2005 012 502 B4 relates to a device for monitoring a filter which is arranged in an air duct of a motor vehicle ventilation, heating and / or air conditioning system, wherein the device comprises a chemical monitoring unit and a physical monitoring unit, wherein the chemical monitoring unit has at least one sensor for measuring the concentration of a lead substance, as well as at least one evaluation electronics for the monitoring units, wherein the physical monitoring unit monitors a flow velocity of the air in the air duct after the filter and / or a pressure difference between a point before the filter and a point after the filter.

[0006] DE 10 2005 027 072 A1 also relates to a control module for controlling a ventilation and / or air conditioning unit for treating interior air in a closed space of a vehicle, in particular a motor vehicle, with one or more sensors for detecting different chemical components of air flows to be examined from the interior air and / or the exterior air, and with a processor unit which, based on signals from the sensors, generates a control signal for controlling the ventilation and / or air conditioning unit, wherein a first air flow to be examined is tapped outside the closed space and fed to at least one sensor for the exterior air, and a second air flow to be examined is tapped from the interior air of the closed space and fed to at least one sensor for the interior air,and wherein a recirculation flap for supplying outside air into the enclosed space and at least one filter for air purification are provided. A device for detecting the current loading state of the at least one filter is provided, which device comprises at least one of the sensors and is constructed such that, in a first measurement, the chemical composition of an air stream passing through the filter is measured, and in a second measurement, the chemical composition of an air stream not passing through the filter is measured, and a value of the current loading state of the filter can be determined from the difference signal between the two measurements.

[0007] FR 3 082 454 B1 further relates to a heating, ventilation and / or air conditioning device for a motor vehicle, wherein the heating, ventilation and / or air conditioning device comprises: a cabin air filter and at least one mass sensor configured to measure a weight of the cabin air filter during use; further, the weight is transmitted to a clogging detection device so that the latter can calculate a weight difference between the weight and an initial weight of the cabin air filter and compare it with a reference weight value.

[0008] DE 101 40 510 A1 describes a method for monitoring the service life of a filter in a filter system equipped with a fan, whereby each time the system is started up, the current air velocity downstream of the filter is measured with a sensor and compared with the reference air velocity from the unloaded filter.

[0009] DE 10 2018 107 943 A1 describes a method for monitoring an air filter, whereby the particle concentration in the ambient air of the vehicle is continuously determined and the particle loading of the air filter is inferred from this.

[0010] DE 10 2014 016 503 A1 discloses a measuring method in which, in order to determine the pressure difference at the air filter of an air conditioning fan of a vehicle, the operating current of the air conditioning fan is determined as an operating variable at a predetermined target speed of the air conditioning fan and a standardized current value is determined as a comparison variable from the operating current determined at the target speed by means of a current reference value and, in order to determine the pressure difference, the standardized current value is compared with at least one stored current reference value as a reference variable.

[0011] The object of the invention is to improve and make more efficient the operation of an air-flow particulate filter in a vehicle, which is particularly suitable for use in a cooling module.

[0012] The invention is based on the features of the independent claims. Advantageous developments and refinements are the subject of the dependent claims.

[0013] A first aspect of the invention relates to a system for creating a diagnosis of the loading state of an air-flown particulate filter of a cooling module of a vehicle with separated particulate matter, comprising a computing unit which is designed to record currently prevailing boundary conditions of the operation of the particulate matter filter and to repeatedly determine a current cooling capacity of the cooling module at different times with boundary conditions within predetermined similarity limits, and to determine a loading state of the particulate matter filter by comparing the current cooling capacity of the cooling module with model values ​​of the cooling capacity of the cooling module that are consistent with the current boundary conditions, and to transmit a command to an output unit for outputting a warning about the loading state of the particulate matter filter if a predetermined limit value is exceeded by the determined loading state.

[0014] Air flows through the particulate matter filter, while the air contains particulate matter. The purpose of the particulate matter filter is to filter out as much particulate matter as possible. However, due to the lack of removal of the captured particulate matter, this also leads to an increasing particulate matter load of the particulate matter filter over time, with the particulate matter trapped there. The amount of particulate matter that has settled on the air filter is expressed by the load state. It is this load state that significantly influences the pressure loss in the air flow through the particulate matter filter. However, since the pressure loss also depends on other boundary conditions, these boundary conditions are recorded during operation of the particulate matter filter and, in particular, checked for similarity before an analysis of the cooling module is carried out. This ensures that the recorded cooling performance achieved by the cooling module can be meaningfully interpreted and conclusions can be drawn about the load state of the particulate matter filter.

[0015] Boundary conditions for the operation of the particulate matter filter preferably include parameters of components of the cooling module and / or a constant control of the cooling module and / or predetermined volume flows of coolant in the cooling module. The term "boundary conditions" thus essentially refers to a set, i.e., a quantity, of individual measurable or estimable variables; however, it can also be understood as meaning that exactly one variable is measured and determined, which naturally determines a multitude of boundary conditions in a complex system such as a cooling module.

[0016] Whenever these boundary conditions are sufficiently similar at different points in time, a comparison of the cooling capacity is possible to derive a loading level of the particulate matter filter. The fact that only points in time during which boundary conditions prevail within specified similarity limits are used for evaluations means that either (at least partially) identical boundary conditions exist, or, if identical boundary conditions are rarely or not realistically achievable, a range of permissible boundary conditions is specified within which the current boundary conditions must lie in order to provide a meaningful point in time for determining the current cooling capacity. In the latter case, the boundary conditions are recorded quantitatively.

[0017] The model values, in particular, indicate expected cooling performance. This allows a comparison of the actual degradation of the particulate matter filter with an expected value over several points in time under boundary conditions to which the model values ​​consistently fit, and thus a deviation from the nominally expected case can be determined. This leaves open both the possibility of considering different boundary conditions and of having corresponding model values ​​for the relevant boundary conditions, as well as the possibility of only one set of boundary condition variables being provided, and accordingly, only one set of model values ​​being available over time, so that only these provided boundary condition variables are recorded as actual values ​​of the current cooling performance.

[0018] In other words, the system is designed to perform the diagnosis under ambient conditions that are as comparable as possible at regular time intervals. Therefore, the charging process of the battery-electric vehicle is suitable according to the invention, i.e. when the vehicle is parked, as soon as the battery charging process begins. Alternatively, detection could be carried out using existing sensors under all vehicle operating conditions, both defined conditions and during normal operation. In the "charging process" operating state, constant boundary conditions are set by the control elements of the thermal system. The radiator shutter (LRS) is fully open, and the fan is operated with a defined, constant control. The cooling circuit is put into a defined operating state by control valves and pumps, which guarantees constant coolant volume flows through the radiator.The cooling rate can be determined using water-side temperature sensors before and after the coolant cooler's inlet and outlet. This is done in conjunction with the ambient air temperature, measured by an air-side sensor. A decrease in cooling performance under this defined, reproducible condition allows for a direct conclusion to be drawn about changes in the air path, i.e., an increasing pressure drop due to a rising particulate filter load.

[0019] Regular diagnosis of the particulate matter filter's load level advantageously enables needs-based control of the particulate matter filter change time. This can conserve material resources and service costs. In particular, it can prevent unnecessary replacement and disposal of the particulate matter filter when it is only slightly loaded with particulate matter. From a certain load level, the user is therefore alerted to the upcoming filter change. This allows for a needs-based filter change. With rigid change interval specifications, it cannot be ruled out that an unnecessary filter change will be carried out on vehicles that are rarely driven in regions with low particulate matter levels. In addition, the diagnosis enables the vehicle to be certified with a defined filter load level, and the filter to be changed during operation as soon as this certified load level is reached, i.e.the certified limit is exceeded. A further advantage of the diagnostic function is that it can detect cases where, for example, the customer's vehicle does not have a particulate matter filter installed or where an unapproved particulate matter filter (e.g., one with an implausible pressure loss) is used.

[0020] According to an advantageous embodiment, the system serves to determine a diagnosis and a prognosis of the loading state of the air-flowed fine dust filter, wherein the computing unit is designed to determine the prognosis of the future loading state of the fine dust filter by determining a change in the cooling capacity of the cooling module from an earlier time to a later time, each with boundary conditions within predetermined similarity limits, and by extrapolating the change, wherein the prognosis of the loading state indicates a future time at which the loading state is expected to exceed the predetermined limit value.

[0021] While the diagnosis indicates the current load level of a particulate matter filter through which air flows, the forecast of the future load level allows an estimate of the future condition. In particular, regular updating of the load level allows a forecast of the remaining service life of the installed filter, which can be displayed to the user, particularly via a human-machine interface in the vehicle. This forecast is advantageously carried out by extrapolating the currently detected increase in the load level of the particulate matter filter.

[0022] According to the invention, the computing unit is designed to detect whether the vehicle's battery is being charged and to select the different times across different charging processes. As explained above, the vehicle's battery charging process in particular offers constant boundary conditions, so that the first time point is advantageously selected for a first charging process and the second time point is advantageously selected for a second charging process, at which the current charge level of the particulate matter filter is determined.

[0023] According to a further advantageous embodiment, the computing unit is designed to select the various points in time such that they occur consecutively at predetermined time intervals. The time intervals specify, in particular, a maximum period of time after which a new point in time should be selected to determine the current loading state of the particulate matter filter. This ensures that the particulate matter filter does not assume a very high loading state undetected.

[0024] According to a further advantageous embodiment, the system further comprises a first temperature sensor for determining an inlet temperature of a coolant cooler of the cooling module and a second temperature sensor for determining an outlet temperature of the coolant cooler of the cooling module, wherein the computing unit is designed to determine a current cooling performance by comparing the temperature respectively determined by the first temperature sensor and the second temperature sensor.

[0025] In principle, the function to be developed is also conceivable with only one water-side temperature sensor.

[0026] According to a further advantageous embodiment, the model values ​​of the cooling module that depend on the boundary conditions are stored in a table as pre-stored setpoints, or are calculated by the computing unit based on the model from the current values ​​of the boundary conditions.

[0027] According to a further advantageous embodiment, the computing unit is designed to store a history of the results on the loading state of the fine dust filter determined since the most recent replacement of the fine dust filter, and to transmit the command to the output unit to output the warning only when the predetermined limit value is exceeded by the determined loading state if the currently determined loading state shows at most a deviation from the trend derived from the history within predetermined limits.

[0028] To rule out malfunctions, such as filter icing in winter, this embodiment documents the history of diagnostic processes performed since the last filter change and checks them for plausibility. Only the combination of a plausible history (continuous increase in filter load with a corresponding gradient) and the exceedance of a specified threshold value should, according to this embodiment, trigger a message alerting the user and, in particular, requesting them to visit a workshop to have the filter changed.

[0029] According to a further advantageous embodiment, the computing unit is designed to determine absolute values ​​of the cooling capacity when determining the cooling capacity and to compare them with the specified limit value.

[0030] According to a further advantageous embodiment, the computing unit is designed to determine absolute values ​​of the cooling capacity and differences in the time course of the cooling capacity between later and earlier times when determining the cooling capacity, and to compare a cost function from the absolute values ​​and the differences with the specified limit value.

[0031] A further aspect of the invention relates to a vehicle with a system as described above and below.

[0032] Advantages and preferred developments of the proposed vehicle result from an analogous and analogous transfer of the statements made above in connection with the proposed system.

[0033] Further advantages, features, and details will become apparent from the following description, which—if appropriate, with reference to the drawings—describes at least one embodiment in detail. Identical, similar, and / or functionally equivalent parts are provided with the same reference numerals.

[0034] It shows: Fig. 1: A system for creating a diagnosis of the loading state of an air-flow particulate filter according to an embodiment of the invention.

[0035] The representations in the figure are schematic and not to scale.

[0036] Fig.1 shows a system for diagnosing the load status of a particulate matter filter 1 of a cooling module 3 of a vehicle through which air flows. The load status is preferably determined as a percentage value. Since the load status of the particulate matter filter indicates the amount of particulate matter separated at the particulate matter filter 1, and the pressure loss of the air flowing through the particulate matter filter 1 typically increases exponentially above the percentage value, a load status of 100% approximately correlates with such a large pressure loss that it can no longer be compensated by increased pump performance. In reality, however, a complete pressure loss is not achieved, since the particulate matter filter 1 cannot assume complete airflow tightness even at a load status of 100%.Conversely, if a different pressure loss occurs at the same volume flow rate, this indicates a changed loading state of the particulate matter filter. To determine this loading state, a computing unit 5 of the vehicle records the currently prevailing boundary conditions for the operation of the particulate matter filter 1 in order to identify boundary conditions that allow a comparison. This comparison is carried out via the recorded cooling capacity of the vehicle's cooling module 3. If the vehicle is an electric vehicle, it can be assumed that the vehicle's battery will be charged after certain maximum expected driving times and / or distances.Such a charging process offers constant boundary conditions in that, in particular, the same opening state of a radiator shutter and the same state of control valves and pumps for constant coolant volume flows through a water cooler can be assumed for each charging process. If the computing unit 5 therefore detects such an electrical charging process of the vehicle's battery, the cooling capacity of the cooling module 3 is determined after a certain settling time (to avoid the detection of transient effects). The cooling capacity is associated with a cooling rate, which is easily calculated using temperature sensors and the recorded time period between the measuring points. For different charging processes, boundary conditions within specified similarity limits are therefore used, and a measurement time is defined for each charging process.By comparing the current cooling capacity of cooling module 3 with model values ​​of the cooling capacity of cooling module 3 for stationary charging processes of the vehicle, depending on the total distance traveled by the vehicle since the most recent particulate matter filter change, the loading state of particulate matter filter 1 is calculated back, based on the underlying assumption that the cooling capacity decreases with increasing loading state of the particulate matter filter through a defined mathematical function. If a predetermined limit value is exceeded by the determined loading state, the computing unit 5 then transmits a command to an output unit to output a warning about the loading state of particulate matter filter 1. Together with the warning, information about a determined forecast of the loading state of the air-flowing particulate matter filter 1 is output.This prediction of the future loading state of the particulate matter filter 1 is made by the computing unit 5 by determining a change in the cooling capacity of the cooling module 3 from an earlier point in time during a first charging process to a later point in time during a second charging process by extrapolating the determined past change. Thus, the user knows a future point in time at which the loading state is likely to exceed the specified limit.

[0037] Although the invention has been illustrated and explained in detail by means of preferred embodiments, the invention is not limited by the disclosed examples, and other variations may be derived therefrom by those skilled in the art without departing from the scope of the invention. It is therefore clear that a multitude of possible variations exist. It is also clear that the embodiments mentioned by way of example are truly only examples and should not be construed as limiting the scope, possible applications, or configuration of the invention in any way.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 departing from the scope of protection defined by the claims and their legal equivalents, such as further explanations in the description.

Claims

[1] System for creating a diagnosis of the loading state of an air-flown particulate filter (1) of a cooling module (3) of a vehicle with separated particulate matter, comprising a computing unit (5) designed to detect currently prevailing boundary conditions of the operation of the particulate filter (1) and to repeatedly determine a current cooling capacity of the cooling module (3) at different times with boundary conditions within predetermined similarity limits, and to determine a loading state of the particulate filter (1) by comparing the current cooling capacity of the cooling module (3) with model values ​​of the cooling capacity of the cooling module (3) that are consistent with the current boundary conditions, and to transmit a command to an output unit for issuing a warning about the loading state of the particulate filter (1) if a predetermined limit value is exceeded by the determined loading state, characterized bythat the computing unit (5) is designed to detect whether a battery charging process of the vehicle is taking place and to select the different times distributed over different charging processes., [2] System according to claim 1, wherein the system is used to determine a diagnosis and a prognosis about the loading state of the air-flown particulate matter filter (1), wherein the computing unit (5) is designed to determine the prognosis about the future loading state of the particulate matter filter (1) by determining a change in the cooling capacity of the cooling module (3) from an earlier point in time to a later point in time, in each case with boundary conditions within predetermined similarity limits, and by extrapolating the change, wherein the prognosis about the loading state indicates a future point in time at which the exceeding of the predetermined limit value by the loading state is expected to occur. [3] System according to one of the preceding claims, wherein the computing unit (5) is designed to select the different points in time such that they lie one after the other at predetermined time intervals. [4] System according to one of the preceding claims, comprising a first temperature sensor for determining an inlet temperature of a coolant cooler of the cooling module (3) and comprising a second temperature sensor for determining an outlet temperature of the coolant cooler of the cooling module (3), wherein the computing unit (5) is designed to determine the current cooling performance by comparing the temperature respectively determined by the first temperature sensor and the second temperature sensor. [5] System according to one of the preceding claims, wherein the model values ​​of the cooling module (3) dependent on the boundary conditions are stored in a table as pre-stored setpoint values, or are calculated model-based by the computing unit (5) from the current values ​​of the boundary conditions. [6] System according to one of the preceding claims, wherein the computing unit (5) is designed to store a history of the results on the loading state of the fine dust filter (1) determined since the most recent replacement of the fine dust filter (1), and to transmit the command to the output unit for issuing the warning only when the predetermined limit value is exceeded by the determined loading state if the currently determined loading state shows at most a deviation from the trend derived from the history within predetermined limits. [7] System according to one of claims 1 to 6, wherein the computing unit (5) is designed to determine absolute values ​​of the cooling capacity when determining the cooling capacity and to compare them with the predetermined limit value. [8] System according to one of claims 1 to 6, wherein the computing unit (5) is designed to determine absolute values ​​of the cooling capacity and differences in the temporal course of the cooling capacity between later and earlier points in time when determining the cooling capacity and to compare a cost function from the absolute values ​​and the differences with the predetermined limit value. [9] Vehicle with a system according to one of the preceding claims.

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