Method for operating an exhaust flap for an exhaust system of a motor vehicle

Abstract

Method for operating an exhaust flap (11) for an exhaust system (4) of a motor vehicle (1) comprising an internal combustion engine (3) and at least one electronic computing device (16) for controlling the internal combustion engine (3), with at least one valve element (12), and with at least one actuator (13) by means of which the valve element (12) is moved, characterized in that the exhaust flap (11) has its own electronic computing device (58) which receives at least one first signal provided by the electronic computing device (16) of the motor vehicle (1) and characterizing a first position of the valve element (12), generates at least one second signal, which characterizes a second position of the valve element (12) different from the first position, depending on the received first signal, and transmits the second signal to the actuator (13).which, by means of the actuator (13), moves the valve element (12) into the second position.

Description

[0001] The invention relates to a method for operating an exhaust flap for an exhaust system of a motor vehicle according to the preamble of claim 1.

[0002] Exhaust flaps of this kind for the exhaust systems of motor vehicles, as well as methods for operating such exhaust flaps, are already well known from the general state of the art and, in particular, from series production vehicle manufacturing. The motor vehicle typically comprises an internal combustion engine by which the vehicle is propelled. During its operation, the internal combustion engine produces exhaust gas, which can flow through the exhaust system. Thus, the exhaust gas is carried away from the internal combustion engine via the exhaust system. Furthermore, the motor vehicle typically has an electronic control unit for regulating and thus operating the internal combustion engine; this electronic control unit is also referred to as a control unit, engine control unit, or engine management system.The exhaust flap comprises at least one valve element and at least one actuator by means of which the valve element is movable, in particular pivotable about a pivot axis. Typically, the valve element is movable, in particular pivotable, between a closed position and at least one open position by means of the actuator.

[0003] The valve element is typically arranged in an exhaust pipe through which the exhaust gas flows, and is movable, in particular pivotable, relative to the exhaust pipe. In the closed position, the valve element fluidically blocks at least a portion of a flow cross-section of the exhaust pipe through which the exhaust gas flows, so that the exhaust gas cannot flow through the fluidically blocked portion. In the open position, however, the valve element releases the portion, allowing the exhaust gas to flow through the released portion.

[0004] Such an exhaust flap is typically used for sound modulation and volume control. In other words, the exhaust flap, and in particular the valve element, can be used to adjust or influence noises emitted by the vehicle, especially the internal combustion engine, into the surroundings, particularly the exhaust system, and which are audibly perceptible to people in the vicinity. Thus, for example, the noise emitted by the vehicle and audibly perceptible to people in the surroundings, as well as its volume, depends on the valve element, and in particular on its position, which is moved and, in particular, held by the actuator.For example, in its open position, the valve element exposes at least one resonator, allowing for a particularly sporty and robust sound. In the closed position, the resonator is blocked by the valve element, resulting in a less sporty but more comfortable sound, which is quieter than the sound in the open position.

[0005] US patent 2016 / 0123210A1 discloses an exhaust gas control system. DE 29500928U1 discloses a device for controlling the power and noise level of an internal combustion engine. DE 112006002343T5 discloses a method and a device for controlling the noise of an engine.

[0006] The object of the present invention is therefore to further develop a method of the type mentioned at the outset in such a way that a particularly advantageous sound modulation and volume control can be realized in a particularly simple manner.

[0007] This problem is solved according to the invention by a method having the features of claim 1. Advantageous embodiments of the invention are the subject of the dependent claims.

[0008] A first aspect, not belonging to the invention, is disclosed, relating to an exhaust flap for an exhaust system of a motor vehicle comprising an internal combustion engine and at least one electronic computing device for controlling or operating the internal combustion engine, which is designed, for example, as a motor vehicle, in particular as a passenger car, and is propelled by means of the internal combustion engine. The internal combustion engine, for example, produces exhaust gas in its combustion operation, which can flow through the exhaust system and is discharged from the internal combustion engine by means of the exhaust system. The exhaust flap comprises at least one valve element and at least one actuator by means of which the valve element is movable, in particular pivotable about a pivot axis.For example, the valve element is arranged in an exhaust pipe, particularly the exhaust flap, through which the exhaust gas of the internal combustion engine flows, and the valve element is movable, in particular pivotable, relative to the exhaust pipe by means of the actuator. The electronic computing device for controlling the internal combustion engine is also referred to as a control unit, engine control unit, or engine control system.

[0009] To achieve particularly advantageous sound modulation and volume control via the exhaust flap, especially by means of the valve element and, in particular, its position, in a particularly simple manner, the exhaust flap has its own electronic processing unit. To clearly distinguish the first-mentioned electronic processing unit for controlling the internal combustion engine from the exhaust flap's own electronic processing unit, the electronic processing unit for controlling the internal combustion engine will also be referred to as the first electronic processing unit, first control unit, engine control unit, or engine control system, while the exhaust flap's own electronic processing unit will also be referred to as the second electronic processing unit, flap control unit, exhaust flap control unit, or second control unit.The term "own," referring to the second electronic computing unit, is intended to clarify or emphasize that the flap control unit (own electronic computing unit of the exhaust flap) is not part of the engine control unit (electronic computing unit for regulating the internal combustion engine) and is not formed by the engine control unit. Rather, the engine control unit and the flap control unit are each considered separately, manufactured components, so that the flap control unit is a control unit distinct from and provided in addition to the engine control unit.

[0010] Thus, the exhaust flap control unit is manufactured independently of the engine control unit, and vice versa. Furthermore, the exhaust flap can be equipped with the flap control unit independently of the engine control unit, and conversely, the vehicle can be equipped with the engine control unit independently of the exhaust flap or the flap control unit. As explained in more detail below, it is also intended that the internal combustion engine, or the vehicle as a whole, can be fully functional even if the exhaust flap and therefore the flap control unit are not installed. Therefore, the exhaust flap is designed as a retrofit solution or aftermarket product with which the vehicle can be equipped after its initial, complete manufacturing. This retrofit solution is also referred to as an aftermarket solution or aftermarket product.In particular, it is conceivable to replace a factory-installed exhaust flap in a vehicle with the exhaust flap, thus retrofitting the vehicle with the exhaust flap as a solution after its initial manufacture and installation with the factory-installed exhaust flap. This allows a factory-installed exhaust system to be converted to a retrofit exhaust system or replaced entirely with a retrofit exhaust system.

[0011] The exhaust flap's own electronic control unit, i.e., the flap control unit, is configured to receive at least one first signal provided by the vehicle's electronic control unit, i.e., the engine control unit, which characterizes a first position of the valve element, and, depending on the received first signal, to generate at least one second signal which characterizes at least one second position of the valve element that differs from the first position. Furthermore, the flap control unit is configured to transmit the second signal to the actuator in order to effect movement of the valve element into the second position by means of the actuator and, in particular, to hold the valve element in the second position by means of the actuator.

[0012] The first signal is, for example, a first control signal provided by the engine control unit (ECU) to actuate a standard actuator of the standard exhaust flap. This actuator then moves a standard valve element of the standard exhaust flap to its first position. In other words, if the vehicle, and in particular its exhaust system, is equipped with the standard exhaust flap, the engine control unit can use the first control signal to actuate the standard actuator. This actuator then moves, specifically pivots, the standard valve element in response to the first control signal.

[0013] Using the exhaust flap as described in the first aspect, it is now possible to easily replace the standard exhaust flap with the exhaust flap as described in the first aspect, without having to replace or extensively modify the engine control unit, and simultaneously to move the valve element not to the first position, but to the desired second position. For this purpose, the flap control unit generates and provides the second signal as a second control signal, so that the actual actuation of the exhaust flap actuator as described in the first aspect is not carried out by the first signal, but by the second signal. Although the valve element is moved based on the first signal, since the second signal is generated in relation to the first signal, the valve element is not moved to the first position, but to the second position, which differs from the first position.This allows the vehicle to be equipped with the exhaust flap, designed as a retrofit solution according to the first aspect, in a particularly simple and cost-effective manner. Furthermore, the exhaust flap, as described in the first aspect, allows the valve element to be moved as needed, enabling particularly advantageous sound modulation and volume control, or allowing a legally compliant exhaust gas level comparable to the standard exhaust system to be achieved in necessary areas. The same applies to the exhaust backpressure, which also depends on the flap position or angle. The backpressure should be identical to that of the standard exhaust system in areas where OPF (Otto Particulate Filter) monitoring is active.

[0014] With regard to the vehicle and the standard exhaust flap, it is therefore possible to easily and precisely influence the position of the valve element, thereby generating a desired sound at a desired volume without having to modify or replace the engine control unit (ECU). Since the flap control unit receives the initial signal provided by the ECU, it simulates, for example, the standard exhaust flap replaced by the flap described in the first aspect. This prevents the ECU from detecting that the flap described in the first aspect is installed instead of the standard one, thus avoiding error messages. The exhaust flap described in the first aspect therefore enables the simple and cost-effective implementation of exhaust flap actuator functionality as a retrofit solution for vehicles, particularly for vehicle exhaust systems.The exhaust flap thus makes it possible, for example, to further close or open the valve element, which would be closed or opened by the first signal, using the second signal. This allows, for instance, the noise emitted by the vehicle, particularly by the internal combustion engine, to its surroundings, especially via the exhaust system, as well as its volume, to be adjusted as needed and influenced or varied – particularly compared to the standard exhaust flap – without requiring complex modifications or replacement of the engine control unit. For example, the valve element is movable, and in particular pivotable, between at least one closed position and at least one open position.

[0015] In the closed position, the valve element, for example, blocks at least a portion of the exhaust gas flow cross-section of the exhaust pipe, preventing the exhaust gas from flowing through the fluidically blocked cross-section. In the open position, however, the valve element releases this portion, allowing the exhaust gas to flow through it. In its open position, the valve element, for example, exposes a damping element, particularly a resonator, while in the closed position, the valve element blocks the resonator or damping element. This allows, for example, a louder and / or sportier sound to be set by opening the valve element compared to closing it, while in closing it, a quieter and, in particular, more comfortable sound can be set compared to opening it.If, for example, the standard exhaust flap is simply replaced with the exhaust flap described in the first aspect, the valve element of the exhaust flap described in the first aspect can be moved into the closed or open position under different conditions compared to the standard valve element of the standard exhaust flap, so that, for example, the open or closed position of the valve element can be set under different conditions. Setting the closed position, the open position, or any position of the valve element in general means that the valve element is moved into the respective position by means of the actuator and, in particular, held in the respective position.

[0016] With the exhaust flap or valve element closed, the exhaust gas passes through a section of the silencer that has the greatest damping. This section also has the highest exhaust backpressure. With the exhaust flap open, the exhaust gas passes through a less damped section in parallel. Less damping usually also means less exhaust backpressure. The exhaust gas takes the easier path and therefore the less damped branch. However, some of it still passes through the more heavily damped section. Modern exhaust flaps don't switch completely, but only open or add to a section.

[0017] The invention is based in particular on the following insight: In the automotive sector, exhaust flaps are increasingly used in exhaust systems. These can be pneumatically or electrically operated or controlled. In particular, such an exhaust flap, and especially its valve element, is used to actively engage at least one damping element, in particular a resonator or resonators. The exhaust flap is not used simply to generate a particularly loud noise that is unpleasant for people in the vicinity of the vehicle, but rather to avoid such unpleasant noises.Almost every internal combustion engine, also known as a motor, combustion engine, or internal combustion power unit, especially turbocharged engines, exhibits operating points at low speeds and loads where the gas exchange or the entire engine / exhaust system becomes noticeable through a droning, humming noise. To still enable comfortable driving under these conditions, damping devices, particularly resonators, are incorporated into the mufflers of the respective exhaust systems. Thus, the aforementioned resonator or damping can be used as an alternative or additional measure to achieve a pleasant and comfortable sound, and consequently, a comfortable ride. However, such a resonator or damping device typically has a negative impact on exhaust backpressure, which is undesirable with regard to gas exchange and fuel consumption.To minimize or eliminate droning and humming noises, preferably only in areas where they are truly needed, adjustable exhaust flaps are used to precisely control the exhaust gas, particularly its flow. For example, by using characteristic maps, the resonator and / or a damped branch(es) can be activated only where and when desired. An exhaust flap can thus be used to prevent unpleasant and excessively loud noises emitted by the vehicle into its surroundings.

[0018] Exhaust flaps are typically used to strike a compromise between what is permitted or regulated and what is specifically desired by the customer. At the same time, unnecessary damping is avoided, as this creates exhaust backpressure. Exhaust backpressure reduces power in certain engine speed / load ranges, and compensating for it increases fuel consumption, which in turn leads to CO2 emissions.

[0019] In sports cars, the entire volume of the muffler may be necessary to achieve sufficient sound dampening. This is achieved, for example, through absorption and / or particularly long pipe runs. This allows for relatively strong sound dampening without excessively increasing exhaust backpressure. In such cases, no volume remains for reflection mufflers or resonators. While reflection mufflers can provide good sound dampening, they also increase exhaust backpressure too much. Resonators generate little exhaust backpressure, but they typically only provide sound dampening within a very narrow range.

[0020] However, exhaust flaps are often used in a much wider range of applications. Besides acoustically differentiating between various driving modes, particularly between comfort and sport modes, exhaust flaps are also used for external noise regulation. Such an exhaust flap can reduce excessive noise or volume emitted by the vehicle, especially the internal combustion engine, through the exhaust system under specific conditions or operating ranges where desired. In other situations—for example, to achieve a sportier sound—the exhaust system can be unblocked by opening the exhaust flap or valve element. Some exhaust flaps are designed as so-called on / off flaps.The valve element is only movable between two distinct positions, one of which is, for example, the aforementioned closed position and the other the aforementioned open position. Furthermore, controlled exhaust flaps are conceivable in which the exhaust flap or valve element can be moved to and held in at least one intermediate position, and in particular several intermediate positions, between the closed and open positions. Using the auxiliary flap control unit as described in the first aspect, including its function, and with appropriate adaptation maps and controlled exhaust flaps, the level and pressure characteristics of a standard exhaust system can be achieved even with a structurally different exhaust system.

[0021] Typically, such an exhaust flap, and especially its actuator, is controlled, at least essentially, directly by the engine control unit (ECU) via the first signal. This first signal usually indicates whether the exhaust flap, or its valve element, should be opened or closed. In the case of a pneumatically operated exhaust flap, the ECU, particularly via the first signal, activates an electric changeover valve, which then creates or releases a vacuum to move the valve element. Therefore, in such a pneumatically operated exhaust flap, the actuator is designed as a pneumatic actuator, which may include the electric changeover valve.

[0022] Various systems exist for electrically adjustable exhaust flaps. In the simplest case, the actuator, designed as an electric actuator, is mounted on the valve element and may incorporate a certain degree of its own artificial intelligence. This includes internal electronics that can automatically move the valve element to its respective end positions. One of these end positions is, for example, the previously mentioned closed position, while another is the previously mentioned open position. The valve element can move from one end position to the other, but not beyond. The actuator, designed as an electric exhaust flap actuator, typically receives its initial signal from the engine control unit, which is usually a PWM signal (pulse width modulation).In particular, the electric exhaust flap actuator receives the PWM signal with a fixed fundamental frequency. Defined pulse-pause ratios are then assigned to the respective desired positions or positions of the actuator or the valve element. A 10% PWM signal, for example, corresponds to the desired opening of the valve element, so that, for example, the valve element is opened, i.e., moved into the open position, by means of such a 10% PWM signal.

[0023] A 90% PWM signal, for example, corresponds to the request to close the valve element. Such a 90% PWM signal closes the valve element, meaning it moves into the closed position. The electric exhaust flap actuator then automatically moves to a specific stop or position, detecting this via an internal current measurement at the actuator motor or its power electronics. At the flap's end stop, the drive current increases, and the actuator, also known as the positioner, automatically shuts off. Modern systems can even move to intermediate positions and are equipped with an additional internal position detection system for this purpose. Furthermore, exhaust flap control systems are known that use exhaust flap actuators or positionser motors containing only a single actuator motor to move the valve element.In these systems, for example, power drivers designed as H-bridges are integrated into the actuator or the motor control unit. These systems are significantly more complex in terms of the motor control unit hardware, but they can continuously control the exhaust flap or valve element, similar to a throttle valve, to any desired position.

[0024] Control via a signal line using PWM is in use. The same applies to any position feedback, which can also be implemented as a PWM signal via a separate line. Even though position feedback is not currently used, it may become necessary in the future, especially if the future use of gasoline particulate filters (GPF) is planned. Exhaust flap manufacturers already offer this. Alternatively, exhaust flap actuator manufacturers also offer LIN bus control. A LIN bus would allow for the parallel transmission of control and position feedback, a more modern approach, and by using two actuators with different addresses, further wiring can be saved. Other bus systems may also be implemented in the future.

[0025] In an advantageous embodiment of the first aspect, the valve element is movable within an adjustment range that includes the second position and a plurality of further positions. The exhaust flap is designed to move the valve element into the positions of the adjustment range and hold it there by means of its own electronic processing unit (flap control unit) and the actuator upon receiving the first signal. In other words, this embodiment provides that the valve element is moved into and held in the different positions of the adjustment range by means of the flap control unit and the actuator, even though the flap control unit only receives the first signal, or rather, the first signal characterizing only the first position.For example, if the standard exhaust flap is designed to move the standard valve element of the standard exhaust flap only between the first position and another end position by means of the engine control unit, and thus move it either into the first position or into the other end position, this can be advantageously and particularly easily modified by means of the exhaust flap designed as a retrofit solution according to the first aspect, such that when only the first position is actually set or is intended to be set by means of the engine control unit, the valve element is moved into several different positions of the adjustment range, especially while the engine control unit provides the first signal.

[0026] In other words, it is preferably provided that, while the engine control unit provides the first signal, or while the flap control unit receives the first signal and thus the first position, the valve element is moved into several different positions within its adjustment range as a result of receiving the first signal, particularly by means of the flap control unit and the actuator, and especially by means of the second signal or signals, which characterize the respective positions within the adjustment range. Thus, for example, the position of the valve element can be changed or varied while the engine control unit only sends the first signal and thus only requests or sets the first position.This allows for particularly advantageous sound modulation and volume control without the engine control unit detecting an error or malfunction, thus preventing errors and fault conditions.

[0027] In order to achieve particularly advantageous sound modulation and volume control, especially via the valve element and in particular via its position or positions, a further embodiment of the first aspect provides that the exhaust flap is designed to move the valve element steplessly to respective positions of the adjustment range by means of its own electronic computing device, by means of the actuator, and in particular by means of the second signal or by means of several second signals, and to hold it in the respective positions.In this embodiment, the exhaust flap, as described in the first aspect, is not designed as a simple on / off exhaust flap whose valve element can only be moved between exactly two positions or in stages between positions. Instead, the exhaust flap is designed such that the valve element can be moved continuously and thus as needed into the positions of the adjustment range, in particular into any position within the adjustment range, and held in the respective position. This allows the aforementioned flow cross-section of the exhaust pipe to be opened and closed fluidically in a particularly demand-oriented manner, and in particular at least essentially continuously and thus seamlessly, thereby enabling particularly advantageous sound modulation and volume control.

[0028] Another embodiment is characterized in that the vehicle's own electronic computing unit (flap control unit) is configured to receive data provided by the vehicle's electronic computing unit, i.e., the engine control unit, and to generate the second signal and thus the second position based on the received data, wherein the data characterizes at least one state of the vehicle that differs from the first position. In other words, the data characterizes at least one state of the vehicle, where the state differs from the first position and thus does not include or characterize the first position.In this embodiment, the second signal, and thus the second position, is generated or set not only depending on the first position, but also depending on at least one additional criterion that differs from the first position, with the aforementioned state encompassing or characterizing the aforementioned criterion. This makes it possible, for example, to adapt the valve element, and in particular its position, to the specific requirements of the vehicle's condition, especially that of the internal combustion engine, thereby enabling particularly advantageous sound modulation and volume control.

[0029] It has proven particularly advantageous if the condition includes the rotational speed of the internal combustion engine or an output shaft of the internal combustion engine, and / or a torque or load of the internal combustion engine, and / or the position of an accelerator pedal of the vehicle, and / or a selected driving mode of the vehicle, and / or the state of a control element operable by a person for operating the exhaust flap. The valve element can thus be moved to different positions depending on the condition or the aforementioned criterion, while, for example, the engine control unit provides the first signal and thus the first position at least essentially constantly, and the flap control unit receives the first signal and the first position, and adjusts it as the condition changes.

[0030] In other words, if, for example, the state changes—where the state or its change is characterized by the data—while the first signal or the first position remains unchanged (i.e., while the valve control unit receives only the first signal and thus only the first position), then the valve element can be moved to different positions by means of the actuator, the valve control unit, and the second signal, even though the first signal or the first position does not change. Thus, it is possible to adapt the valve element, and in particular its position, to the changing state or changes in the state, even though the engine control unit only requests the first position.If, for example, the standard exhaust flap were installed, the position of the standard valve element would not change despite changes in the system's condition, as the engine control unit (ECU) would still request the first position. However, since the standard exhaust flap can now be replaced by the exhaust flap described in the first aspect in a particularly simple and cost-effective manner, the valve element can be moved as a result of changes in the system's condition and thus moved into different positions, especially by means of the second signal or multiple second signals, even though and while the ECU only requests the first position.

[0031] In a further development of the first aspect, a characteristic map comprising the second position and several positions distinct from each other and from the second position is stored in a memory unit of the integrated electronic computing unit (valve control unit). The integrated electronic computing unit (valve control unit) is configured to select one of the positions from the characteristic map based on the received first signal and to effect movement of the valve element to the selected position by means of the actuator. Thus, for example, the second signal characterizes the selected position, allowing the valve element to be moved to the selected position by means of the second signal. In particular, the valve element is held in the selected position by means of the actuator, thereby enabling particularly advantageous sound modulation and volume control.It is preferably intended that the positions of the characteristic map are the positions of the adjustment range.

[0032] By using the map, it is possible to correct the initial signal or position so that the valve element is not moved to the first position requested by the engine control unit, but rather to a different second position or a different selected position. In particular, this makes it possible to move the valve element to different positions selected from the map, while the engine control unit only requests the first position. This allows the noise and volume emitted by the vehicle, especially the internal combustion engine, to its surroundings, particularly via the exhaust system, to be influenced precisely as needed.

[0033] In order to be able to move the valve element particularly quickly and as required, it is preferably provided that the actuator is designed as an electrically operated actuator, i.e. as an electric actuator.

[0034] Finally, it has proven particularly advantageous if the exhaust flap is designed to detect at least the second position using its own electronic control unit (flap control unit), to generate a feedback signal characterizing the first position based on the detection of the second position, and to provide this feedback signal to the electronic control unit of the vehicle. In particular, the flap control unit can, for example, detect different positions of the valve element, which is moved into these different positions based on a characteristic map, and, depending on the detection of each position, generate the feedback signal characterizing the first position and provide this feedback signal to the electronic control unit of the vehicle.Preferably, the flap control unit can detect the respective positions of the adjustment range or the characteristic map and, depending on the detection of the respective position, generate the feedback signal that characterizes the first position and provide the feedback signal to the electronic computing unit of the motor vehicle.

[0035] This embodiment is based in particular on the following insight: The engine control unit can, for example, be configured to detect the position of the valve element, especially within the framework of a diagnostic function. As described above, the engine control unit requests the first position using the first signal, but the second signal is used to set at least the second position of the valve element, which differs from the first position. If, for example, the exhaust flap were to detect the set second position of the valve element and report this detected second position back to the engine control unit, especially via the feedback signal, the engine control unit would detect and report an error, since it would recognize that the actually set second position of the valve element deviates from the first position requested and desired by the engine control unit.Consequently, an error message or fault code would be generated, even though the exhaust flap is functioning correctly and the valve element is moved to and held in the desired second position. To avoid such an unwanted and erroneous fault detection, the flap control unit does not report the desired second position to the engine control unit, but rather the first position requested by the engine control unit via the feedback signal. This allows the engine control unit to register a fault-free function, which is indeed the case.

[0036] In other words, the engine control unit (ECU) is fundamentally designed to verify whether the initial signal it provides actually causes the valve element to move to the first position, meaning whether the valve element is indeed in the first position requested by the ECU. For example, if the standard exhaust flap were installed and functioning correctly, the initial signal would indeed cause the standard valve element to move to the first position requested by the ECU. The ECU would detect this and diagnose the standard exhaust flap as functioning correctly.

[0037] However, since the flap control unit sets the second position and not the first position of the valve element, if the engine control unit were to receive feedback of the actually set second position, an error message would be generated. This error would occur because the engine control unit would detect that the second position deviates from the first position it requires. Therefore, the system reports back not the actually set second position, but the first position requested by the engine control unit.

[0038] To still achieve an advantageous diagnostic function, the flap control unit is preferably designed to detect the position of the valve element or to verify whether the valve element is actually in the second position, i.e., whether the second signal actually causes the second position. If, for example, the flap control unit detects that the valve element is not in the second position requested by the flap control unit, but in a position different from the second position, such as the first position, the flap control unit assumes an error or malfunction, since the second signal should have caused the second position, but has not. Consequently, the feedback signal to the engine control unit, for example, does not report the first position, but a position different from the first position.This informs the engine control unit that a malfunction has occurred, as it simulates the valve element not being in the first position requested by the engine control unit. Overall, this enables a particularly advantageous diagnostic function, since unwanted and unnecessary error messages can be avoided, and faults are only detected and error messages generated when a malfunction of the exhaust flap actually exists.

[0039] Also disclosed is a second aspect, not belonging to the invention, which relates to a control unit for an exhaust flap of an exhaust system of a motor vehicle comprising at least one valve element and at least one actuator by means of which the valve element can be moved, wherein the control unit is configured to receive at least one first signal provided by an electronic computing device of the motor vehicle, in particular of the exhaust system, and characterizing a first position of the valve element, to generate at least one second signal, depending on the received first signal, characterizing a second position of the valve element that differs from the first position, and to transmit the second signal to the actuator in order to effect a movement of the valve element into the second position by means of the actuator.Advantages and beneficial designs of the first aspect are to be regarded as advantages and beneficial designs of the second aspect, and vice versa. The control unit according to the second aspect is thus, for example, the aforementioned separate or second electronic computing device by means of which a particularly advantageous sound modulation can be achieved.

[0040] The control unit according to the second aspect thus offers the possibility to operate the exhaust flap of the exhaust system, for example as an after-sales exhaust system, in such a way that on the one hand a particularly emotional sound can be realized and on the other hand relevant requirements regarding the avoidance of excessively loud noises can be met, in particular with regard to the external noise directive R51.03.

[0041] The control unit according to the second aspect is therefore a control unit that, for example, simulates the behavior and hardware of the exhaust flaps (which are switched) with regard to engine control, particularly concerning diagnostic feedback or any position feedback. In the aftermarket exhaust system, the control unit according to the second aspect then controls the exhaust flap not by switching, but by regulating it. In other words, the control unit according to the second aspect makes it possible, for example, to operate the exhaust flap, which is normally controlled and thus only adjustable between two discrete positions, or its valve element, as a regulated exhaust flap or a regulated valve element, so that the valve element can be moved at least essentially continuously between the positions and can also be moved to and held in several other positions, particularly those located between the positions.The control unit recognizes, for example, when the engine control, implemented by the electronic computing unit of the motor vehicle, would switch the valve element of the standard exhaust system, designed as a flap, and then controls the regulated exhaust flap or several regulated exhaust flaps of the after-sales exhaust system accordingly.

[0042] In Comfort, Sport, and Sport+ modes, the control unit now uses predefined positions in the map to ensure that the aftermarket exhaust system operates at approximately the same noise level as the standard exhaust system. This guarantees that, particularly in areas requiring road approval, an aftermarket exhaust system capable of producing a more emotional sound than the standard system can achieve a sufficiently low noise level—corresponding to that of the standard exhaust system—by adjusting the valve element positions or angles accordingly. In addition to the "open" and "closed" signals for controlling the exhaust flaps, for example via CAN bus, the control unit also receives information regarding engine speed, torque, gear, and driving modes, allowing for further differentiation within the maps.

[0043] In addition to the sound levels for the approval ranges, regulated exhaust flaps, also simply referred to as flaps, and corresponding maps can be used to similarly design the overall exhaust sound level of an aftermarket exhaust system for the standard Comfort, Sport, and Sport+ driving modes. This offers advantages in conjunction with the artificial ASD sound, which is conveyed to the driver inside the vehicle. This ASD sound is applied based on the stock exhaust outlet. Besides the sound itself, the applied sound level is particularly important. Where a stock exhaust system allows a low sound level into the vehicle interior, more sound is amplified; conversely, where the stock exhaust system exhibits noticeable sound peaks, less sound is amplified. The overall sound must be harmonious.

[0044] An aftermarket exhaust system typically has different peaks and troughs in its sound level. Internal Active Sound (IASD) and aftermarket exhaust systems therefore often don't work well together. If an aftermarket exhaust system has a peak at the same point where the stock exhaust has a dip, it can be unpleasant for the driver. The artificial sound system in the stock exhaust already compensates for or adds to the dip in the sound level. The aftermarket exhaust system then amplifies the sound even further. The combination of both could be too much. The ECU, as mentioned in the second aspect, at least has a map to compensate for this.

[0045] For this purpose, the standard exhaust system is measured on a rolling road dynamometer. The levels for the valve or valve element in "open" and "closed" positions can be determined, and corresponding acceleration tests with varying torque are performed. The procedure is identical for the aftermarket exhaust system, except that here the valve(s) are measured not only in "open" and "closed" modes, but also in intermediate positions, for example, "closed = 0%", 5%, 10%, 15%...80%, 85%, and "open = 80%". The resulting curves can then be used to create the engine maps. With this approach, the aftermarket exhaust system may sound different, but the levels are approximately identical.

[0046] In after-sales service, a push button is often used to open the exhaust flap(s). This can also be implemented here. A separate map can be used to pre-control the exhaust flap only in those areas where it's required for type approval. All areas not affected by type approval can be set to their normal noise level. The control unit can then even make the transitions extremely steep or smooth. Conversely, fault feedback and any existing position feedback should also be configured via maps. The engine control unit should receive what it expects; that is, the protocol should be followed. In addition to the noise level, exhaust back pressure can also play an important role, which is particularly relevant when introducing or using an OPF (Otto Particulate Filter).

[0047] In principle, an exhaust flap, or rather its valve element, opens a less damped section of the exhaust system. It cannot switch over because the damped section of the exhaust system remains. This damped section also causes greater exhaust backpressure. Therefore, when an exhaust flap or valve element is opened, the exhaust gas always seeks the easier path, i.e., the less damped path, where the flap or valve element is typically located or which it opens. In a standard exhaust system, however, the exhaust flap is usually followed by further damping. This is either an upstream damping element, which also applies to the closed flap, or a downstream damping element. In the past, this area was exploited in the aftermarket to generate even higher sound levels.The upstream damping was removed and reintroduced in the flap "closed" range, and damping in the flap "open" range was minimized. This approach no longer works with the usual flap implementation and control system.

[0048] A third aspect belonging to the invention relates to a method for operating an exhaust flap for an exhaust system of a motor vehicle comprising an internal combustion engine and at least one electronic computing device for controlling the internal combustion engine, with at least one valve element of the exhaust flap and with at least one actuator of the exhaust flap by means of which the valve element is moved.

[0049] In order to achieve particularly advantageous sound modulation and volume control in a particularly simple manner, the invention provides that the exhaust flap has its own electronic processing unit, which receives at least one first signal provided by the electronic processing unit of the motor vehicle and characterizing a first position of the valve element, generates at least one second signal, different from the first position, depending on the received first signal, and transmits the second signal to the actuator, whereby the actuator moves the valve element into the second position and, in particular, holds it in the second position. Advantages and advantageous embodiments of the first aspect and the second aspect are to be regarded as advantages and advantageous embodiments of the third aspect of the invention, and vice versa.

[0050] The method thus offers, or rather is a function, that makes it possible to connect two identical actuator concepts (switched) or two different actuator concepts (switched basic / regulated after-sales) in such a way that an after-sales exhaust system can be operated under harsher new conditions (regarding sound and exhaust backpressure) and can be adjusted with regard to the exhaust levels, all without the engine control being able to detect this, especially with regard to the signals that the standard actuators usually send back, with regard to the exhaust backpressure that a standard exhaust system usually delivers when the flap is "open / closed" and which, in combination with a particulate filter, represents an important monitoring value for filter regeneration.

[0051] Overall, it's clear that the actuator is a control unit for the exhaust flap. Typically, the actuator has its own control system, which can also be understood as regulation. The reason for this is the actuation process. In principle, an engine control unit could also directly control such a flap. However, the engine control unit would then have to run two wires to the exhaust flap at the rear of the vehicle to directly operate the small actuator. This is very complex and, especially with regulated flaps that don't provide position feedback to the engine control unit, almost impossible. The complexity lies in the wiring. An electric exhaust flap only has one control wire; it receives its power supply locally. If the engine control unit were to handle this, it would need a second wire just for the actuation.Position detection might then require an additional line, which is all very complex, and the power electronics would have to be integrated into the motor control unit. Therefore, self-contained electric actuators have become the standard.

[0052] Overall, it is also evident that the control unit, as described in the second aspect, is installed in place of the standard exhaust flap or the control unit of the standard exhaust flap, simulating, for example, the standard exhaust flap(s) and the protocols expected by the engine control unit. The flap control unit, as described in the second aspect, is connected to one or more exhaust flaps, such as regulated ones, particularly those from the aftermarket. These exhaust flap(s) can also be conventional, switched flaps. The control unit, as described in the second aspect, ensures that the engine control unit's signal to the aftermarket exhaust system regarding level and exhaust backpressure is adapted in relevant areas via at least one map, and that corresponding error messages, which can vary depending on the actuator, are translated or adjusted accordingly.

[0053] The control unit (flap control unit) according to the second aspect can, for example, open the flap(s) or valve element(s) by means of a retrofitted button, but no longer as freely as was possible under the old external noise directive. In areas relevant to type approval and in areas where a defined exhaust back pressure is expected, the button requirement is secondary, as function and legislation take precedence over driver preference.

[0054] The engine control unit would need to maintain variant maps for the different exhaust system, for example, for an aftermarket exhaust system, or separate data sets would need to be used and maintained. All of this would incur considerable costs. This can now be avoided by using the control unit as described in the second aspect.

[0055] By using the control unit as described in the second aspect, the engine control unit (ECU) does not recognize the aftermarket exhaust system or exhaust flap installed in place of the standard exhaust system or flap, but instead assumes the original, switched exhaust flap is installed. If a fault occurs, it can only process the error messages that an electric actuator of such an exhaust flap can generate. If the flap control unit described in the second aspect, including its functionality, is installed instead of the switched exhaust flap, this control unit takes over the error messages. However, the error messages no longer originate from a switched, but from a regulated exhaust flap. These errors can be completely different – ​​depending on the actuator and the software running on it. The transmission method can also differ.Such an adjustable actuator might, for example, be controlled via linear frequency (LIN) instead of PWM. Consequently, the error logs would likely look different. The flap control unit must convert the logs accordingly so that they arrive at the engine control unit (ECU) in the correct format. The flap control unit must ensure that the ECU feeds back all information in the same format as a standard switched actuator would. This also applies, for example, to a fed-back position signal, even though we are not currently using that.

[0056] If a switched exhaust flap actuator were used in the standard configuration, it could only report the end positions. Intermediate values ​​would occur during the switching process, but only because it travels through them to the end stop. A static value between the end stops would be interpreted as an error. A variable exhaust flap would also move to positions between 0 and 90% of the standard exhaust flap's opening range. This is the advantage of a variable exhaust flap and its combination with an aftermarket exhaust system. If the engine control unit switches the presumed exhaust flap to the "open" position, and the flap or auxiliary control unit can only set the new variable exhaust flap to 70% "open" at this operating point because it would otherwise be too loud for the external noise measurement, then it must report 90% back to the engine control unit, not 70%. This is what the engine control unit expects. It would otherwise consider a prolonged period at 70% as an error.

[0057] Level and pressure adjustment play a crucial role. Most vehicles have different driving modes, such as Comfort, Sport, and Sport+. Each mode has its own exhaust flap map, which uses gear, engine speed, pedal position, and potentially load and / or exhaust mass flow to open or close the flaps. Currently, standard systems simply open or close the flaps. In the future, electronically controlled exhaust flaps could be used, operating similarly but with intermediate positions.

[0058] In the past, aftermarket exhaust system suppliers offered a remote control that allowed the exhaust flap to be switched via a button. This control always started with the flap closed upon restarting the vehicle, thus ensuring compliance with regulations. These switches are no longer, or at least hardly, feasible, as all modes and switches now have to be checked according to the new external noise guidelines. Aftermarket suppliers can no longer meet these requirements. The control unit, as described in the second aspect, is designed to make all of this possible again, regardless of whether the factory exhaust system uses a switched or regulated exhaust flap and whether the aftermarket exhaust system uses a switched or regulated exhaust flap. Therefore, all combinations are possible. The map can then ensure that, with a louder exhaust system and adjusted flap angles, the noise levels in Comfort, Sport, and Sport+ modes are similar to the factory system.This would result in fewer complaints regarding artificial sound enhancement via electronic systems like IASD. In areas relevant for vehicle approval, the same external sound levels could then be achieved using appropriate adaptation maps. The same applies to comfort-related areas.

[0059] The same applies to the future use of gasoline particulate filters (GPFs). These must be monitored for exhaust backpressure, which is currently proving very difficult. Based on the exhaust backpressure, software must initiate a corresponding regeneration cycle to burn off the soot and debris in the filter. Otherwise, it will eventually become clogged. Exhaust backpressure reduces fuel consumption, thus increasing CO2 emissions and also reducing power. If an aftermarket exhaust system exhibits varying exhaust backpressure in the future, the engine control unit (ECU) may not be able to distinguish this from a clogged filter. It might then initiate regeneration too frequently or too infrequently, both of which are unacceptable. In addition to adjusting the levels for acoustics and regulatory compliance, it's also possible to adjust the exhaust backpressure of an aftermarket exhaust system to the same values ​​as a standard factory exhaust system, especially if the precise operating ranges in which the ECU detects this backpressure are known.

[0060] If, for example, the goal isn't to adjust levels related to artificial sound and comfort, then only the areas relevant for type approval and the OPF measurement need to be ensured. Then, when a button is pressed, a map could be used to program only these small areas with corresponding exhaust flap angles. It would even be possible to approach the level limits of the ASEP envelope curve even more closely. All areas outside the new external noise guidelines and all areas where exhaust backpressure isn't a concern would be freely applicable. Here, an exhaust flap could be fully opened without restriction or operated only at angles that deviate from the basic acoustics. The control unit has access to the engine speed, gear, torque, pedal angle, etc., via the CAN bus, and thus all the necessary information to implement this precisely.

[0061] Further details of the invention will become apparent from the following description of preferred embodiments with the accompanying drawings.

[0062] This shows: Fig. 1 a schematic side view of a motor vehicle designed as a passenger car, with an internal combustion engine for propelling the motor vehicle, with an exhaust system through which exhaust gas from the internal combustion engine flows, with an electronic computing device for controlling the internal combustion engine, and with an exhaust flap arranged in the exhaust system; Fig. 2. A schematic and enlarged side view of the motor vehicle (in part); Fig. 3 a schematic perspective view of the exhaust flap; Fig. 4 a schematic representation of an electronic computing device for the exhaust flap according to a first embodiment; Fig. 5 a schematic representation of the electronic computing device of the exhaust flap according to a second embodiment; Fig. 6. Partial schematic top view of the exhaust system according to a first embodiment; Fig. 7. Partial schematic top view of the exhaust system according to a second embodiment; Fig. 8 a diagram to illustrate the loudness of a noise depending on different boundary conditions; Fig. 9 a schematic representation to illustrate the operation of exhaust flaps; Fig. 10 a schematic representation to illustrate the operation of the exhaust flap; Fig. 11 a diagram to illustrate the operation of the exhaust flap; and Fig. 12 a schematic representation of the electronic computing device of the exhaust flap according to a third embodiment.

[0063] In the figures, identical or functionally equivalent elements are provided with the same reference numerals.

[0064] Fig. Figure 1 shows a schematic side view of a motor vehicle 1 designed as a motor vehicle, in particular as a passenger vehicle, wherein in Fig. Figure 2 shows an enlarged view of the rear section 2 of the motor vehicle 1. The motor vehicle 1 has an internal combustion engine 3 by means of which the motor vehicle 1 can be propelled. The internal combustion engine 3 is also referred to as a motor, internal combustion engine, or combustion power engine and is, for example, designed as a reciprocating piston engine. The internal combustion engine 3 has at least one combustion chamber, in particular several combustion chambers, wherein the respective combustion chamber is preferably designed as a cylinder. During firing operation of the internal combustion engine 3, at least fuel and air are supplied to the combustion chamber, so that a fuel-air mixture is formed in the respective combustion chamber. The fuel-air mixture is ignited, in particular by spark ignition, and thereby combusted, resulting in exhaust gas from the internal combustion engine 3.The fuel is, for example, a liquid fuel for operating the internal combustion engine 3.

[0065] The motor vehicle 1 also has an exhaust system 4 through which the exhaust gas can flow. The exhaust gas from the internal combustion engine 3, or more precisely from the combustion chamber, is carried away by means of the exhaust system 4. The exhaust system 4 includes, for example, a manifold 5, also referred to as an exhaust manifold, by means of which the exhaust gas from the several combustion chambers is collected.

[0066] The exhaust system 4 is arranged, in particular in the upward direction of the vehicle, under the underbody of the motor vehicle 1, in particular under a superstructure 6 of the motor vehicle 1, and is held in place by the underbody. The superstructure 6 is located in the Fig. 1 and Fig. The illustrated embodiment 2 is designed as a self-supporting body or shell. It consists of Fig. 1 Retaining elements 7 are visible, by means of which the exhaust system 4 is held, in particular suspended, on the underbody. The retaining elements 7 are designed, for example, as suspension elements and are also referred to as exhaust system suspension elements. In particular, the retaining elements 7 are formed, at least in part, from rubber, so that relative movements between the exhaust system 4 and the underbody are dampened by deformation of the rubber.

[0067] The exhaust system 4 has a rear silencer 8 through which the exhaust gas flows. This rear silencer is also simply called a muffler and is used to dampen unwanted noise. Downstream of the rear silencer 8, a tailpipe 9 of the exhaust system 4, also referred to as an exhaust pipe, opens to the surroundings 10. Thus, the exhaust gas flowing through the exhaust system 4 can flow to the surroundings 10 via the tailpipe 9, meaning that no further silencer is connected to the tailpipe 9. In other words, downstream of the tailpipe 9, there is no further silencer in the direction of exhaust gas flow. The tailpipe 9 is, for example, an exhaust pipe through which the exhaust gas flows.

[0068] The exhaust system 4 also includes one in Fig. 1 particularly schematically represented exhaust flap 11, which is particularly well made of Fig. 2. A recognizable valve element 12 is present. The valve element 12 is located in the Fig. 1 and Fig. The illustrated embodiment 2 is designed as a flap, specifically as a butterfly flap or butterfly valve. Furthermore, the exhaust flap 11 has an actuator 13 by means of which the valve element 12 is movable, in particular pivotable. The actuator 13 is designed as an electric actuator, or as an electrically actuated or operable actuator, and thus comprises at least one electric motor by means of which the valve element 12 can be moved. The actuator 13 is also referred to as an electric exhaust flap actuator, actuator, flap actuator, or valve actuator. By means of the actuator 13, the valve element 12 is movable—as will be explained in more detail below—between at least two different positions, in particular pivotable, wherein the valve element 12 is movable relative to the exhaust pipe (tailpipe 9).One of the positions is, for example, a closed position of the valve element 12, while the other position is, for example, an open position of the valve element 12. In the closed position, the valve element 12 blocks at least a portion of a flow cross-section of the exhaust system 4, preferably the tailpipe 9, through which the exhaust gas can flow, so that the exhaust gas cannot flow through the blocked portion. In the open position, however, the valve element 12 releases the portion, so that the exhaust gas can flow through it. The tailpipe 9, or at least a section of its length, can be part of the exhaust flap 11, such that the valve element 12 is, for example, movable, and in particular pivotable, within that section. [This last sentence appears to be a fragment and is omitted.] Fig. 2 it can be seen that the end pipe 9 has an outlet 14, also referred to as the end pipe opening, through which the end pipe 9 opens into the surroundings 10.

[0069] Furthermore, exhaust systems are conceivable in which the exhaust flap is located upstream of the rear silencer (DE 10 2013 208 946 A1). In this design, all tailpipes are then used. Nevertheless, the same principle applies: when the flap is closed, the exhaust gas is blocked from taking the more direct route (with less exhaust backpressure and less damping).

[0070] The motor vehicle 1 also includes a particularly well-made Fig. 1. A recognizable and schematically depicted electronic computing device 16, which is assigned to the internal combustion engine 3 and is also referred to as the engine control unit or engine control system. The internal combustion engine 3 is controlled and thus operated by means of the electronic computing device 16, which is also referred to as the first electronic computing device.

[0071] As from Fig. As can be seen in Figure 2, it is usually provided that the actuator 13 of the exhaust flap 11 is connected to the engine control unit (electronic computing unit 16), for example, via at least one line 15 or via a wiring harness comprising at least line 15, and thus linked to the engine control unit. In particular, the engine control unit is configured to send electrical signals as electrical or electronic control signals and, in particular, to transmit them via line 15 to the actuator 13, which is configured to receive the control signals from the engine control unit. This typically allows the actuator 13 to be controlled by the engine control unit, in particular at least substantially directly, thereby moving the valve element 12. Thus, the valve element 12 is moved via the actuator 13 by means of the engine control unit. The connection of the actuator 13 to the engine control unit described above is shown in Figure 2. Fig. 2 illustrated by an arrow 75.

[0072] Fig. Figure 3 shows the exhaust flap 11 as an example in a schematic perspective view. The aforementioned length range, in which the valve element 12 is movable, in particular pivotable, is shown in Fig. 3 with 17 and is formed, for example, by a pipe section 18 through which the exhaust gas flows. Furthermore, the flow cross-section through which the exhaust gas flows, which can be at least partially fluidically blocked and released by means of the valve element 12, is in Fig. 3 with 19. The pipe section 18 is also referred to, for example, as the exhaust flap section and is installed in the exhaust pipe (tailpipe 9), particularly in the fully manufactured state of the motor vehicle 1. Furthermore, it is conceivable that the exhaust flap 11 is arranged upstream of the tailpipe 9.

[0073] The pipe section 18 is connected to a mounting bracket 20, which may be designed as a mounting plate and has a screw preparation 21 for the actuator 13. The actuator 13 is connected to the mounting bracket 20 by means of the screw preparation 21, specifically by screws, so that the actuator 13 is connected to the pipe section 18 via the screw preparation 21 and the mounting bracket 20. This results in, for example, the exhaust flap 11 forming an easy-to-handle and easy-to-install module. Furthermore, thermal insulation 22 is provided, which surrounds, for example, the actuator 13 or its electronic and / or mechanical components, in order to protect the actuator 13 components from excessive heat exposure.

[0074] As from Fig. As can be seen from Figures 1 to 3, the exhaust flap 11 is usually installed upstream of the last silencer of the exhaust system 4 and thus downstream of the secondary silencer 8, particularly shortly before the outlet 14. The exhaust flap 11, especially the valve element 12, may be at least partially visible, for example, if a person looks into the exhaust system 4 through the outlet 14. Alternatively, the exhaust flap 11 could be located next to or upstream of the secondary silencer 8. It is also possible to install the exhaust flap 11 in a central section of the exhaust system 4, for example, to enable switchable crosstalk between at least two pipe sections in a dual-flow exhaust system. This arrangement of the exhaust flap 11 can offer advantages with regard to operating noise.The further back in the exhaust system the exhaust flap 11 is located, the more likely one is to hear metallic clanging or possibly flow noise while the exhaust flap 11, or rather the valve element 12, changes its position. Furthermore, as shown in the diagram above, all tailpipes can be used with both the exhaust flap open and closed. If the flap is installed before the muffler, further absorption can be implemented downstream, which can then reduce flow noise – possibly through a variable flap with intermediate positions.

[0075] Fig. Figure 4 illustrates the actuator 13, in particular its electrical design, of the exhaust flap 11 according to a first embodiment. The actuator 13 has a connector 79, also referred to as a component connector or pin, and mounting tabs 23, by means of which the actuator 13 can be screwed to the mounting bracket 20. Each mounting tab 23 has a through-hole into which a slotted metal sleeve 24 is inserted. A connector 25, referred to as a wiring harness connector, is also visible, which is connected to, for example, the line 15 or is part of the line 15. The connector 25 is connected to the connector 79, thus electrically connecting, for example, the connectors 79 and 25. This electrically connects the actuator 13 to the line 15, enabling it to be electrically connected to the engine control unit via the line 15.The plug 79, and thus the actuator 13, can be supplied with energy, in particular electrical energy, via a connection 26, so that, for example, the actuator 13 can be electrically connected to a power supply or to a voltage source of the motor vehicle 1 via connection 26. The power supply is, for example, a battery, whereby the power supply can provide, for example, a switched supply voltage.

[0076] Actuator 14 is a controller that, for example, incorporates an electric motor. This motor, via a worm drive and gearbox or just a gearbox, can drive an actuator shaft in both directions to adjust the valve element 12. To simplify operation, the controller has electronics that control the motor accordingly when a command is received from a higher-level control unit. The electronics detect whether the end positions are reached by monitoring the motor current. A time window is also considered. Modern versions incorporate a small encoder wheel, which allows the positions between the end positions to be detected. Simple on / off actuators can also detect the end positions using this feature. Modern controllers utilize this additional component to also move to intermediate positions or to provide continuous control. Control and command transmission can be achieved in various ways, such as PWM, LIN, etc.If a position sensor or orientation sensor is already installed, the actuator can then also make this information available to the higher-level control unit, for example also via an additional PWM line or via the same LIN or bus line for control.

[0077] A signal connection to the engine control unit is established via terminal 27, allowing, for example, the actuator 13 and the engine control unit to exchange electrical signals via terminal 27. Specifically, the actuator 13 can receive the aforementioned control signals from the engine control unit via terminal 27. A further terminal 28 allows the actuator 13 to be connected to the vehicle ground or a corresponding grounding point. In the case of the Fig. In the illustrated embodiment 4, a further connection 29 is not used. The connections 26, 27 and 28, or the respective line elements connected to the connections 26, 27 and 28, are to be used in addition to the aforementioned and in Fig. 4 cable harnesses labeled 78 are grouped together, whose connectors are in Fig. 4 is labelled with 25.

[0078] Furthermore, the actuator 13 has a housing 30, which is made, for example, of a plastic. The housing 30 comprises, for example, a lower shell and an upper shell connected to the lower shell.

[0079] For example, connector 79 is electrically connected to a circuit board 31 containing control electronics, the circuit board 31 being housed in the casing 30 and forming part of the actuator 13. The control electronics may, for example, be a microcontroller. Furthermore, the circuit board 31 may include power electronics, which may include, in particular, an H-bridge. The aforementioned electric motor is an electric machine and is in Fig. 4 labeled with 32. From Fig. Figure 4 shows that the electric motor 32 can be controlled by the microcontroller to move the valve element 12. The electric motor 32 comprises a stator and a rotor 33, which is rotatable about an axis of rotation relative to the stator. The rotor 33 has a rotor shaft 34, via which a gear unit 36 ​​of the actuator 13 can be driven by the electric motor 32. A drive shaft 35 of the valve element 12 can be driven by the electric motor 32 via the gear unit 36, thereby pivoting the valve element 12, particularly relative to the pipe section 18. To drive the valve element 12 by means of the electric motor 32 and thereby move it relative to the pipe section 18, in particular to pivot it, the electric motor 32 is supplied with electrical energy or an electric current.This electric current, with which the electric motor 32 is supplied to move the valve element 12 in the manner described, can be controlled by means of a [connection / connection]. Fig. The current measurement 77, shown in a particularly schematic representation, is recorded and thus measured. For this purpose, the current measurement 77 includes, for example, at least one sensor for recording the current with which the electric motor 32 is supplied in order to move the valve element 12.

[0080] The engine control unit, for example, is a higher-level control unit from which the actuator 13, in particular the electric motor 32, receives a command to open or close the valve element 12 via line 15, which is designed as a signal line. Line 15 is, for example, the line element that is connected to terminal 27, so that the actuator 13, in particular the microcontroller, receives the aforementioned command to open or close the valve element 12. The actuator 13, also referred to as the controller, then executes the command independently.As soon as the actuator receives a position request from the engine control unit as a command, the electric motor 32, and consequently the valve element 12, are set in motion, provided the position request characterizes a position that differs from the current position of the valve element 12. The microcontroller (µC), for example, controls the H-bridge so that the electric motor 32, which may be a DC motor, or its rotor 33, rotates in the correct direction to move the valve element 12 from its current position to the position characterized by the position request, in particular to pivot it. When the electric motor 32, and thus the valve element 12, begins to move, a starting current is measured, which supplies power to the electric motor 32.At the same time, a timer is started, which is also called a counter or timer.

[0081] The valve element 12, designed, for example, as a flap, now moves at a substantially constant speed to the position characterized by the desired position, in particular to an opposite stop. If the exhaust flap 11 is designed, for example, as a simple open-close flap, the valve element 12 can only be moved precisely to these two positions, such that each position is an end position. The end position is also referred to as the end stop or stop, meaning that the valve element 12 can only be moved precisely to the respective end positions, but not beyond them, and in particular, cannot be held in the end positions, but not in intermediate positions between the end positions. Once the valve element 12 reaches its end position, it cannot be moved further by the electric motor 32, so that the electric motor 32 or the rotor 33 can no longer move.This simultaneously leads to a stall current or short-circuit current, which can be detected by the current sensor 77. The stall current or short-circuit current is an increasing electric current, which, particularly because the stall current is detected by the current sensor 77, the microcontroller can use as end-of-travel detection. In other words, the microcontroller can recognize, based on the detected stall current, that the valve element 12 has reached its end position.

[0082] For this purpose, the microcontroller compares, for example, the stall current with the starting current, particularly taking into account the runtime determined by the timer. The stall current is greater than the starting current. The runtime characterizes, for example, the time interval that extends from the point at which the timer is started until the point at which the stall current is measured. The stall current and the runtime are values ​​that the microcontroller or the controller uses to determine whether the valve element 12 has actually reached the desired end position, i.e., whether it is fully closed. This can only be the case if the runtime has reached or exceeded a minimum value.Furthermore, the controller can use the values ​​to determine whether the valve element 12 has become stuck before reaching its end position and thus has not reached the end position, particularly if the stall current is detected before the runtime reaches its minimum value. The controller can also detect in this way that the valve element 12 is very difficult to adjust, which may indicate excessive wear and / or excessive contamination and / or damage.

[0083] This is particularly the case when the runtime exceeds a maximum value, meaning that too much time is required to move the valve element 12 to its end position. Consequently, a fault can be detected. Such and other fault cases are transmitted to the higher-level control unit (engine control unit) by, for example, pulling the signal line to ground for a defined period. Larger control units in the automotive sector thus detect short circuits to ground in the wiring harness 78. For example, the signal line is pulled to ground for a defined period of, say, five seconds. This allows the higher-level control unit to distinguish between wiring harness and actuator problems. Such actuators with integrated intelligence have the advantage that they can be connected relatively easily to various higher-level control units.The higher-level control unit only needs to provide a simple output pin for this purpose, which can, for example, supply a PWM signal with the appropriate frequency and pulse-pause ratio (PWM - Pulse Width Modulation). With such electrically operated exhaust flap positions, it is also possible to diagnose the correct functioning of the actuator. If, for example, the actuator or the valve element 12 does not reach the respective end positions or stops within a specified time, or if the actuator is no longer connected to the engine control unit, this can be detected via internal fault or performance diagnostics. Modern actuators with internal position detection are even more easily monitored. Only pneumatic systems can be diagnosed only up to the electrical changeover valve. If an exhaust flap jams in these systems, this cannot be detected by the engine control unit.The changeover valve only receives an electrical signal indicating whether it is open or closed. This signal can also be used by the auxiliary control unit to control subsequently switched or regulated exhaust flaps on another exhaust system.

[0084] Fig. Figure 5 illustrates a second embodiment in which a position detection device 37 is provided. The position detection device 37 comprises at least one position sensor 38, which is also referred to as a position sensor. By means of the position sensor 38, and thus by means of the position detection device 37, at least one position of the valve element 12 can be detected, at least indirectly. In other words, the respective positions into which the valve element 12 can be moved by means of the actuator 13 can be detected, at least indirectly, by means of the position detection device 37. This detection of the respective position of the valve element 12 is also referred to as position detection and is carried out in this case on the basis of the drive shaft 35.In particular, it is possible to detect the respective rotational positions of the drive axis 35 using the position sensor 38, so that the respective position of the valve element 12 can be determined based on the respective detected rotational position, since the respective rotational position of the drive axis 35 corresponds to a respective position of the valve element 12.

[0085] At the in Fig. In the embodiment illustrated in Figure 5, the terminal 29 is occupied, with at least one conductor element being electronically connected to the terminal 29. The position of the valve element 12, determined by the position sensor 37, is reported back to the engine control unit via the terminal 29, thus enabling position feedback.

[0086] Overall, it is evident that the exhaust flap 11 is designed as an electric exhaust flap system. There are several reasons for using such electric exhaust flap systems. For example, the manufacturer of the vehicle 1 aims to avoid unwanted, unpleasant, and / or excessively loud external noises and to meet corresponding requirements by using such electric exhaust flap systems. At the same time, the system provides the driver of the vehicle 1 and / or people in the vicinity 10 with a sporty sound, particularly external noise, under certain driving conditions, without being excessively loud. Without the use of such exhaust flaps, the exhaust flap 11 would have to be designed to always withstand a specific external noise type test. However, noise reduction in an exhaust system always has the negative effect of increasing exhaust back pressure.As the exhaust mass flow increases, the exhaust back pressure can negatively impact performance and fuel consumption. This is particularly pronounced in the upper engine speed / load range for exhaust systems without an exhaust flap.

[0087] Noise emitted by the motor vehicle 1, in particular the internal combustion engine 3, for example via the exhaust system 4 and especially via the outlet 14 to the surroundings 10, is determined, for example, by means of an external noise measurement. The external noise measurement is carried out, for example, in a high-start mode of the motor vehicle 1. The motor vehicle 1, or rather the internal combustion engine 3, is started, and no driving mode switch, etc., in the motor vehicle 1 is activated. Under these conditions, an accelerated drive-by is carried out in a noise measurement section. This section is entered, for example, at 50 kilometers per hour, and then full-load acceleration is performed. In a vehicle with a manual transmission, this is normally done in third gear, and in less powerful vehicles in second gear. In vehicles with automatic transmissions, the corresponding automatic mode is used.The above paragraph refers in particular to an old directive concerning noise emissions.

[0088] The following is a general description of a new guideline, for example, the exterior noise guideline R51.03. Other methods for measuring exterior noise, particularly those under the new guideline, no longer differentiate between vehicles with manual and automatic transmissions. Exterior noise is measured in one or two fixed gears. The gear used for measurement is determined by the acceleration achieved over the test track. The target is approximately two meters per second squared. During this test, a speed of 50 kilometers per hour must be reached within the microphone's range. The same section must then be driven again at a constant speed of 50 kilometers per hour in the same gear. A single value is calculated from both measured noise levels, which must be below a specific limit.These new measurement systems are designed to ensure equal opportunities and reproducibility. Depending on whether an accelerated pass is to be determined using one or two gears, a value is calculated from the measured levels and the levels from a constant 50 km / h drive using the same gears. This calculated value must be below a legally defined limit.

[0089] Another method for measuring external noise is called ASEP or the ASEP method, which is also simply referred to as the test or ASEP test. In this test, a noise level ramp-up curve is determined in different gears at different engine speeds. This measured noise level ramp-up must be determined in different gears for all driving mode settings. Which gears and engine speeds are used is determined by formulas and the vehicle's achievable break-in engine speeds.

[0090] These level curves must lie below a defined limit or envelope, which is calculated using a formula and the loudest point during the pass-by. This is to ensure that no function is applied behind the exhaust flap control that only closes the exhaust flap during the external noise measurement. It is also intended to prevent a situation where noise reduction is completely absent in certain modes or during sportier settings. In short, it is essential to ensure that the exhaust flap control is reproducible and that the level difference between the various sport modes remains within certain tolerable limits.For example, if a vehicle has a separate button to open or close exhaust flap 11 or valve element 12, then the vehicle must pass the test in high-start mode and subsequently the ASEP test with the exhaust flap (valve element 12) closed and with it open. In such a case, the noise level with the exhaust flap open would likely be higher in the test, but only within permissible limits. Unlike the previous legislation, damping would now have to be present even with the exhaust flap open. However, since the test only needs to be performed in certain gears and at certain engine speeds, this would have disadvantages at higher engine speeds, particularly regarding fuel consumption. If the delta between open and closed is designed to be extreme, it may be necessary to keep the exhaust flaps closed throughout the entire ASEP test range.Imagine a vehicle in Sport mode where the exhaust flaps are always closed up to, say, 4000 rpm in 2nd, 3rd, and 4th gear. The sportiness is gone. To prevent this effect, the damping for the flap-open range must be increased, but this also reduces the potential for performance beyond the legal limits.

[0091] Especially in the aftermarket, accessories have been offered in the past that allow the exhaust flap to be controlled independently of the manufacturer's software. These systems are most effective when the vehicle manufacturer only installs exhaust systems without an exhaust flap. In such cases, exhaust systems with additional exhaust flaps are installed. An external control unit then allows the respective exhaust flap, or its valve element, to be opened or closed as needed. In high-start mode, the systems initially close the exhaust flap to achieve the required drive-by noise level according to the type approval specifications. The exhaust flap can then be opened and closed again simply by pressing a button.After a restart or a shutdown of the internal combustion engine, the exhaust flap is always moved back to its initial state and thus closed, so that compliance with external noise regulations can be achieved.

[0092] These systems are usually push-button systems connected to the electric exhaust flap actuator or the electric changeover valve of pneumatic systems. These systems operate either via direct electrical connections or wirelessly, utilizing technologies such as Wi-Fi, Bluetooth, and / or other wireless radio links to control the actuator. Wireless connectivity, in particular, allows for easy retrofitting.

[0093] Newer developments, in particular, severely restrict the freedom to shape the exterior noise. The exhaust flap can no longer be kept constantly open outside of the high-start mode. In all driving modes in which the ASEP test must be performed, a closed exhaust flap is required, especially depending on the exhaust system design. The only exception would be if the entire exhaust system were designed in such a way that the noise could be kept sufficiently low with the exhaust flap open. However, this is not very realistic, as the vehicle could then only be quieter using a corresponding exhaust flap button, and the exhaust backpressure would increase dramatically. Therefore, it is no longer possible to fully open the exhaust flap across all gears and the entire engine speed and load range, which could have a significant economic impact on aftermarket exhaust system manufacturers.In principle, it's not particularly difficult to create an aftermarket exhaust system that meets legal noise limits with the exhaust flap closed and is louder than a standard exhaust system with the flap open. The real challenge lies in building an exhaust system that sounds completely different, uses the same control system, and thus passes the same testing procedures in the same areas, while also maintaining the same exhaust backpressure in certain situations, especially if a particulate filter is present. Normally, the supplier of such an exhaust system uses a standard exhaust flap control system, as this typically closes the flap during the ambient noise measurement. However, what might work for the acoustic measurement of an accelerated pass-by is not suitable for the ASEP test. The following example calculation explains how the aforementioned ASEP level envelope can be determined.The decisive factor is the maximum sound level reached during the accelerated pass-by. This starting point provides the anchor point for an expected regression line. In this case, it is the expected sound level with increasing engine speed. The slope is specified by law using the formula 5 + 1 dB(A) / 1000 min⁻¹. A limit curve, also calculated according to legal requirements, is shifted relative to this curve. Maximum permissible sound level: D = Llimit - Lurban + 2 dB(A) => D = 75 dB(A) - 71.8 dB(A) + 2 dB(A) = B = 5.2 dB(A).

[0094] In different gears, a level ramp-up curve must now be determined by taking measurements at microphone height from low engine speeds under full load in each gear at various engine speeds. To limit the effort involved, the legislation restricts this to a specific range. Thus, for example, only third and fourth gear need to be used for ASEP measurements.

[0095] While all pressure points at the various engine speeds with a closed exhaust flap (L_VL_TEST_KLAPPE ZU) lie below the limit curve (L_LIMIT), this is not the case with an open exhaust flap (L_VL_TEST_KLAPPE AUF). Only the last point at 3,000 rpm lies below the limit curve. To achieve maximum acoustic sportiness in the standard application in Sport and Sport+ modes, the standard application would therefore look like this: exhaust flap closes in third and fourth gear up to approximately 2,800 rpm and opens from approximately 2,800 rpm. This last point in particular will likely cause problems for aftermarket exhaust system manufacturers.

[0096] This will be illustrated by the following description. It shows Fig. Figure 6 shows a schematic top view of a standard rear silencer 39, which has a rear silencer housing 40 and an exhaust pipe 41 coming from the internal combustion engine 3. The exhaust pipe 41 leads into the standard rear silencer 39 or into its rear silencer housing 40 and branches out in the rear silencer housing 40. Fig. 6 is designated as 42, the first path through which the exhaust gas flows, while 43 is designated as a second path through which the exhaust gas flows. The exhaust pipe 41 branches into paths 42 and 43 within the rear silencer housing 40. Path 42 is acoustically more attenuated than path 43, which is achieved, for example, by perforation and / or other means such as reflection chambers and / or cross-sectional reduction. Path 43 is the less attenuated, and therefore louder, path or branch, which is achieved, for example, directly by less perforation and / or cross-sectional optimization. Path 42 is only active when path 43 is blocked by the exhaust flap 11 or the valve element 12. When the exhaust flap is open, path 43, the louder branch, dominates.The exhaust flap 11 is assigned to or located within path 43, so that path 43 can be opened and closed as needed by means of the exhaust flap 11. In the closed position, for example, path 43 is fluidically blocked, so that the exhaust gas does not flow through path 43, or only very minimally, and flows at least predominantly or completely through path 42. In the open position, however, the exhaust flap 11 opens path 43, so that the exhaust gas then flows through both paths 42 and 43.

[0097] Furthermore, in Fig. The six tailpipe outlets of the standard rear silencer 39 are designated 44, allowing exhaust gas to flow from the standard rear silencer 39 to the surroundings 10 via the tailpipe outlets 44. The standard rear silencer 39 is also simply referred to as a rear silencer or muffler. By using the exhaust flap 11, the standard rear silencer can generate two exhaust sound level curves, particularly under full load, each resulting in a noise that is audibly perceptible to a person in the surroundings 10.

[0098] The individual sounds of the muzzle level curves differ, for example, in their loudness. This shows Fig. Figure 8 shows a diagram on whose abscissa 45 a parameter such as the rotational speed (n) or the load (M) of the internal combustion engine 3 or the exhaust gas mass flow (Ams) is plotted. On the ordinate 46 of the diagram, for example, the exhaust noise level, represented linearly for simplification, and thus the loudness of the respective noise, is plotted. A curve 47 illustrates, for example, the noise or its loudness with the exhaust flap 11 closed or with the valve element 12 closed as a function of the increasing parameter, i.e., with the increasing rotational speed or the increasing load. A curve 48 illustrates the noise as a function of the increasing parameter with the exhaust flap 11 open or with the valve element 12 open. Furthermore, in Fig. 8 a double arrow 49 the exhaust back pressure. Thus, from Fig. It can be seen that the exhaust back pressure is higher when the valve element 12 is closed than when the valve element 12 is open. Depending on the damping of paths 42 and 43, the following results when the exhaust flap 11 or the valve element 12 is open: the curve 48, representing one level curve, and when the exhaust flap 11 or the valve element 12 is closed: the curve 47, representing another level curve, is obtained, particularly at the respective tailpipe outlet 44. When the valve element 12 is closed, only path 42 dampens, and this path has greater absorption than path 43, i.e., stronger damping. The damped path 43 is then closed by the exhaust flap 11.This circumstance also ensures in most cases that the exhaust backpressure increases with a closed exhaust flap 11 above the parameter, i.e., above the rotational speed n, above the torque M, or with increasing exhaust mass flow Ams, so that the aforementioned parameter can also include the exhaust mass flow. In this case, damping via absorption is shown. More or less absorption does not have a very significant influence on exhaust backpressure. If further methods are used for damping—which are difficult to illustrate here—such as cross-sectional reduction, reflection chambers, longer pipe lengths, etc., then this has a significant influence on the exhaust backpressure.

[0099] Fig. Figure 7 shows a schematic top view of a rear silencer 50, designed, for example, as an aftermarket rear silencer, which also has an exhaust pipe 41 and a rear silencer housing 40 in which the exhaust pipe 41 branches into paths 51 and 52. In the rear silencer 50, path 51 is also acoustically damped more strongly than path 52; for example, path 51 is damped to the same degree as path 42. In other words, path 51 has the same acoustic damping effect as path 52, or path 51 has greater damping than path 42, also referred to as the standard branch. It is very unlikely that an aftermarket exhaust system with a different design would have identical damping in the remaining branch (the undamped branch is blocked by an exhaust flap) to the standard exhaust system. It is likely to be slightly higher or lower. In this example, more damping.The same applies to the exhaust backpressure behavior if the design – unlike in this example – is completely different. This value, too, can be above or below the standard value under the same operating conditions.

[0100] Path 52, for example, has no damping, or its damping is reduced to a minimum, so that path 52 dampens the noise less than path 43. To thus acoustically distinguish itself from the standard exhaust system, the damping of paths 51 and 52 is designed differently than the damping of paths 42 and 43. Depending on the damping of paths 43 and 52, for example, a closed valve element 12 results in a Fig. 8 illustrated by a curve 53 and, with the valve element 12 closed, a level curve in Fig. Figure 8 illustrates the level curve, particularly at the respective tailpipe outlet 44. The same applies to the exhaust backpressure. For simplicity, the curves are shown linearly in the example. In reality, the curve exhibits significant increases and partial dips. With different exhaust systems, these increases and dips in the level can occur at completely different engine speed / load ranges. When the valve element 12 is closed, only path 51 dampens, possibly with a stronger or higher absorption than path 42. Ideally, such an accessory should achieve exactly the same damping as the standard exhaust system to produce a similar level in the drive-by measurement. However, achieving this in the design is very complex.This circumstance also ensures in most cases that the exhaust back pressure increases with increasing engine speed n, torque M, or exhaust mass flow Ams when valve element 12 is closed, and may even be higher compared to the standard exhaust system. In the previously mentioned example, the damping is due to the damping of the component, which is designed, for example, as an accessory solution.

[0101] With the exhaust flap 11 closed, the sound level of the aftermarket silencer 50 is slightly below that of the standard aftermarket silencer 39. However, with the exhaust flap 11 open, the situation is exactly the opposite. The sound level of the aftermarket silencer 50 is significantly higher than that of the standard aftermarket silencer 39. This is precisely the intended effect of the aftermarket exhaust system, which is designed to be acoustically more prominent than the standard exhaust system. However, this design of the aftermarket exhaust system is counteracted by the ASEP test.

[0102] The significantly higher noise level of an aftermarket exhaust system with open exhaust flaps becomes a problem during the ASEP test if the standard exhaust flap application is already inadequate. The preceding and following explanations represent a highly simplified version of the ASEP test. In the example above, an ASEP measurement demonstrated that the standard exhaust system can open the exhaust flaps in Sport and Sport+ modes in third and fourth gear from approximately 2,800 rpm. This is only the case because the measurement with the exhaust flap open resulted in a noise level below the calculated limit curve. If, for example, a retrofit exhaust system (also known as an aftermarket exhaust system) with the significantly higher noise level shown above, exhibiting an open exhaust flap, is installed, then a type approval test will fail precisely in this range.Even if the damping curve with the exhaust flap 11 closed – as shown in the example – is below that of the standard exhaust system, problems can still arise. If the standard drive-by measurement is quieter, this simultaneously reduces the limit curve for the ASEP test. If, during the baseline measurement – ​​i.e., the accelerated drive-by – with a more damping exhaust system, too much safety margin is built in relative to the limit, this is also reflected in the limit curve of the ASEP test. The quieter the drive-by, the less potential for noise levels exists in the ASEP test. Therefore, it is virtually impossible to replace standard exhaust systems with aftermarket solutions. This is especially true if the standard application for the exhaust flap is to be retained.

[0103] One way to solve this problem is to use controlled exhaust flaps instead of switched ones. A switched exhaust flap is a type of on / off exhaust flap, as described above, whose valve element can only be moved to and held in exactly two positions. A controlled exhaust flap, on the other hand, is a type of exhaust flap whose valve element can be moved not only to the positions mentioned above, but also to several other positions, and held in these additional positions. These additional positions include, for example, intermediate positions between the positions mentioned above, specifically between the closed and open positions.In particular, it is possible, for example, to move the valve element 12 continuously between its end positions and thus to move it continuously into positions between the end positions and hold it in these positions, so that, for example, the flow cross-section 19 through which the exhaust gas flows can be continuously adjusted, especially between the end positions. Such a controlled exhaust flap is also referred to as an angle-adjustable exhaust flap. Even if angle-adjustable exhaust flaps were used in a standard exhaust system, such a control unit, including the function, would presumably be required to enable adjustment of the opening angle. While it would be conceivable to adjust the maps directly in the engine control software, this is very complex and requires the necessary resources, either through predefined coding variants or additional data sets.The effort and costs are very high and are therefore usually avoided.

[0104] Fig. Figure 9 illustrates, for example, a standard exhaust system whose exhaust flap 11 is located in Fig. Figure 9 is shown particularly schematically. Furthermore, an optional exhaust flap, designated 55, is provided, whereby the preceding and following explanations regarding exhaust flap 11 can readily be applied to exhaust flap 55 and vice versa. The aforementioned signal line, connected, for example, to terminal 27, is also referred to as the control line and is shown in Fig. 9 is labelled with 56. The control line 56 is also referred to as the trigger line. From Fig. Figure 9 shows that the exhaust flap 11 or 55 is electrically connected, at least substantially, directly to the engine control unit (electronic computing unit 16) via the respective control line 56. The aforementioned position feedback, also referred to as position feedback, is transmitted via a feedback line 57. The control line can transmit various pieces of information to control different systems: - A simple high or low level on the control line can, for example, control an electromagnetic switching valve, which in turn switches a vacuum actuator and the exhaust flap or valve element 12 attached to it. - Two control lines can also be used to directly drive an electric motor integrated into the exhaust flap actuator. The power output stage is integrated into the motor control unit, and the actuator position can be regulated via the feedback signal. - An intelligent exhaust flap actuator can be controlled or regulated via a control line. This can be achieved either through two simple pulse-pause ratios for "open" and "closed" or through a complete pulse-pause band across the entire opening angle. Position feedback can be provided via a separate line. Fault diagnostics can be performed via both the control line and the position feedback line. - The latter option can also be implemented via Lin or CAN instead of PWM.

[0105] Lines 57 and 56 could also consist of a single line, for example, a LIN bus. With a LIN bus, the two controllers could then be connected to the same bus and distinguished by their different IDs.

[0106] Regardless of the actuator used in the standard exhaust system, a technology is required for retrofitting, i.e., for after-sales applications, to influence or correct the exhaust level. It has been found that this can be achieved particularly well using adjustable exhaust flaps, specifically those adjustable via the angle or opening angle. These are elements that allow an exhaust pipe to be not only simply closed or opened, but also to transition continuously between these two states. Therefore, it is preferably provided that the valve element 12 can be moved at least substantially continuously or steplessly between its end positions and held in positions located between these end positions.This allows the valve element 12 to function as a valve that can continuously reduce or increase the flow cross-section 19 of the pipe section 18, in particular its diameter. In other words, by means of the continuously movable valve element 12 between the end positions, it is possible to adjust the flow cross-section 19 at least essentially continuously, or to continuously set and maintain specific values ​​of the flow cross-section 19.

[0107] In order to make this advantageous for retrofit solutions and thus easy to use in the after-sales area, it is intended that the exhaust flap 11 - as shown in Fig. As can be seen in Figure 10, the exhaust flap 11 has its own electronic computing unit 58, which is separate from or additional to the electronic computing unit 16 and is also referred to as an auxiliary control unit or flap control unit. The attribute "separate" with regard to the electronic computing unit 58 of the exhaust flap 11 is intended to clarify that the flap control unit (electronic computing unit 58) is not formed by the already provided engine control unit (electronic computing unit 16), but rather the electronic computing units 16 and 58 are respective, separately designed individual components. It is possible to easily integrate the auxiliary control unit (flap control unit) into or connect it in between the existing wiring harness 78, and it is also conceivable to tap into additional information for CAN, LIN, etc. at a suitable point.

[0108] By using the flap control unit, it is possible to replace an exhaust flap of a standard exhaust system with the exhaust flap 11 comprised of the additional flap control unit. This allows the additional flap control unit to simulate, for example, removed exhaust flap actuator components or the removed exhaust flap itself (also referred to as the standard exhaust flap) that was previously installed in place of exhaust flap 11, particularly for the engine control unit. The electronic computing unit 58, for example, replicates an input interface of the previously installed standard exhaust flap and subsequently returns any error logs from its new control component to the engine control unit. The same applies to adapted position feedback. For instance, not only the error logs are returned, but also the interface itself.The engine control unit can detect whether the intended component is installed or whether, for example, a component is disconnected, regardless of whether a changeover valve is being controlled or via PWM. A disconnected component or a broken wire is detected and must be implemented in the hardware input of the auxiliary control unit in the same way as in the component that replaces the control unit.

[0109] Out of Fig. It is evident from Figure 10 that, because the exhaust flap 11 includes its own electronic computing unit 58, the standard exhaust flap can simply be replaced by the exhaust flap 11 without having to extensively modify or replace the engine control unit (electronic computing unit 16). Fig. It is also apparent from Figure 10 that the exhaust flap 11, for example, includes the actuator 13, which can be controlled by the flap control unit. Furthermore, it is apparent that the exhaust flap 11 includes at least one additional valve element, provided in addition to the valve element 12, which can be moved by means of a further actuator 59. The preceding and following descriptions regarding the valve element 12 can readily be applied to the further valve element, and vice versa.

[0110] As in Fig. 9. The lines between the DME and the auxiliary control unit can be individual PWM lines or just a bus line, such as LIN. Similarly, the lines between auxiliary control unit 58 and the new exhaust flap actuators can also be PWM or LIN, as shown in... Fig. 9.

[0111] In Fig. Figure 10 further shows a particularly schematic bus system 76, which is configured, for example, as a CAN bus and / or LIN bus. The flap control unit can receive data from the engine control unit via the bus system 76, which is a data bus system, wherein the data includes at least one state of the motor vehicle 1, in particular the internal combustion engine 3.The flap control unit is now designed to receive at least one first, in particular electrical, signal provided by the engine control unit and characterizing a first position of the valve element 12 via the control line 56, to generate at least one second signal characterizing at least one second position of the valve element 12 that differs from the first position depending on the received first signal, and to transmit the second signal to the actuator 13 in order to effect a movement of the valve element 12 into the second position by means of the actuator 13.In particular, the flap control unit is designed to generate the second signal or several second signals depending on the first signal and thereby – while the flap control unit receives the first signal and while the first signal merely characterizes the first position – to move the valve element 12 via the actuator 13 into different positions, in particular continuously or steplessly, and to hold it in these positions, so that – while the flap control unit receives the first signal and while the first signal merely characterizes the first position – different values ​​of the flow cross-section 19 are set and maintained. Although in . Fig. Item 10 is not shown; however, additional information can be provided via a separate button for after-sales service. This could also be integrated directly into the auxiliary control unit as hardware, or via radio or elsewhere into the bus system.

[0112] The function of exhaust flap 11 with the additional control unit is explained using the following: Fig. 11 clearly. Fig. Figure 11 shows curves 47 and 48, as well as further curves 60, 61, 62, and 63 illustrating respective level curves, which, for example, represent the respective full-load exhaust levels. The exhaust flap 11 is not designed as a switched flap, but rather as an adjustable or controllable exhaust flap via its angle. In a position labeled 0 percent, the valve element 12 is closed, thus reducing the flow cross-section 19 to 0. In a position labeled 100 percent, the valve element 12 is open, so that the valve element 12 allows the maximum flow cross-section. Thus, 0 percent designates one of the end positions, while 100 percent designates the second end position of the valve element 12. Between the 0 percent and 100 percent positions, there are further positions into which the valve element 12 can be moved and held.

[0113] For example, curve 60 illustrates the 0% position of valve element 12, meaning when valve element 12 is 0% open. Curve 47 illustrates valve element 12 open to 10%, while with respect to the standard exhaust flap, valve element 12 is closed in curve 47. Curve 61 illustrates valve element 12 closed to 20%, while curve 62 illustrates valve element 12 closed to 60%. Curve 48 illustrates valve element 12 closed to 80%, while curve 48 with respect to the standard exhaust flap illustrates valve element 12 fully open. Furthermore, curve 63 illustrates valve element 12 open to 100%.

[0114] In this idealized case, the retrofit solution with an exhaust flap or valve element angle of 80 percent will have approximately the same run-up level as the standard exhaust system with the exhaust flap open. The same applies to the desired damping. In the example above, the retrofit solution with a 10 percent open exhaust flap will roughly match the level of a standard exhaust system with the exhaust flap closed. This example presents an ideal case with only slightly modified hardware. With completely different hardware, the level curves of a standard on / off system and an aftermarket-controlled system can be entirely different. To replicate the opening or closing curve of a standard exhaust system with an aftermarket system, different angles may be required during the run-up phase. This can be determined on a test bench and then continuously controlled later using maps.

[0115] In a simple embodiment, the auxiliary control unit only requires the on / off switching commands provided by the engine control unit and converts these into corresponding output information to not only open and close the valve element 12, but also to move it to and hold it in the aforementioned positions that differ from the end positions, for example, positions between the end positions, which are also referred to as intermediate positions. This can be achieved using appropriate correction maps. If the level ramp-up curves differ significantly depending on the speed and load, such a correction map can be implemented more precisely. For example, a complete map based on speed and / or load can be stored for the closed state, which can adjust the angle of the damped output characteristic depending on the required orifice level. The same applies to the desired open state.Here too, it's conceivable to precisely adjust the exhaust curve using a corresponding map from the series. If such an auxiliary control unit has access to the vehicle's CAN bus, all the necessary information is available, including engine speed, torque, pedal angle, driving modes, etc. Even the exhaust flap's switching request is also available on the CAN bus.

[0116] The engine control unit (ECU) switches the exhaust flaps using corresponding maps. Often there are several of these maps, for example, one for Comfort, Sport, and Sport+. Within these maps, the exhaust flap is opened or closed for each gear across specific engine speed ranges, depending on the pedal angle. Thus, depending on the map design, a very precise adjustment of the exhaust gas levels to the standard exhaust system could be achieved with an additional control unit. A standard exhaust flap application is implemented based on various parameters. In a high-start mode, usually Comfort, the exhaust flap must initially be closed during the drive-by emissions test for type approval in most cases. Since a relatively quiet and comfortable vehicle is desired in Comfort mode, many areas in the lower engine speed / load range are also configured for a closed exhaust flap.

[0117] In sport modes, the exhaust flap opens much more frequently and earlier. By supplying the auxiliary control unit with further information via bus system 76, the level adjustment can be made even more precise. This information can include details such as the engaged gear, the selected driving mode, the pedal angle, and so on. Based on this information and the desired flap position of the standard application, the auxiliary control unit can then store a customized aftermarket exhaust map. As described above, this can ideally correspond to the level of the standard exhaust system. Such an implementation would have further advantages. Often, the vehicle's interior acoustics are artificially enhanced. Engine sounds are played through the audio system into the cabin to simulate a sporty engine sound.The levels of such artificial exhaust assistance are often based on the existing exhaust level in the vehicle, i.e., what the standard exhaust system provides. The levels of the two systems are adjusted to create a harmonious acoustic profile. In engine speed / load ranges where the standard exhaust system exhibits unfavorable acoustics, more artificial assistance can be added, and vice versa. Therefore, if the exhaust levels of an aftermarket exhaust system are adjusted via the auxiliary control unit, it has less of an impact on the standard exhaust sound. This could be particularly advantageous for the basic driving modes: Comfort, Sport, and Sport+.

[0118] What applies to the noise level may also need to be applied to exhaust backpressure in certain areas. If gasoline particulate filters are introduced in the future and their exhaust backpressure is monitored in specific RPM / load ranges, then it's advisable to ensure that the expected exhaust backpressure is identical to the standard setup in these ranges before considering the acoustics. This applies unless the acoustics are within the legal limits. A previously common additional button for exhaust flap control can also be implemented using the auxiliary control unit. This is precisely where the potential of a retrofitted exhaust system can be fully realized. In an additional map, the so-called button map, the exhaust system can now be completely opened almost everywhere, if desired.

[0119] The comfort setting, which can also be adjusted via the flap in almost all driving modes of a standard exhaust system, can be ignored here. With maximum implementation, the control unit would only regulate the areas relevant for type approval and the area where the exhaust backpressure must be correct. In some countries, a map variant with country-specific coding would also be conceivable, which would only include the exhaust backpressure adjustment ranges. If there are countries where a particulate filter (OPF) is used, this range could even be ignored by the button.

[0120] Based on Fig. Section 12 describes the auxiliary control unit (electronic computing unit 58) in more detail. For example, adaptation fields 65, 66, 67, and 68 are stored in a memory unit 64 of the flap control unit. These adaptation fields 65, 66, 67, and 68 are assigned to respective driving modes, with adaptation map 68 being, for example, the aforementioned button map. Furthermore, additional adaptation maps 69a-d can be used. Furthermore, in Fig. The microcontrollers of actuators 13 and 59 are designated 70. Actuator 13 is controlled, for example, by PWM, while actuator 59 is controlled, for example, by linear frequency. Furthermore, in Fig. 12. A microcontroller of the flap control unit is designated 71, and a microcontroller of the engine control unit is designated 72. The aforementioned button for operating or actuating the exhaust flap 11 is in Fig. 12 is designated by 73, such that the button 73 is a control element for operating or actuating the exhaust flap 11. For example, the control element is connected to the electronic computing unit 58 via a wireless data connection, in particular a radio connection, such as WLAN, Bluetooth or the like. Alternatively, it is conceivable that the control element is connected to the flap control unit (electronic computing unit 58) via at least one physically present line 74, in particular electrically.

[0121] Overall, it is from Fig.It is evident from Figure 12 that the aforementioned two valve elements can be moved via actuators 13 and 59 using the flap control unit. The type of actuator used is irrelevant. In particular, it is conceivable that two power outputs are provided for each actuator. The auxiliary control unit, specifically adaptation fields 65, 66, and 67, contains data for the Comfort, Sport, and Sport+ driving modes. The characteristic maps interpret the specifications from the engine control unit and convert them into corresponding specifications for the respective angle-adjustable actuator 13 or 59. Both diagnostic and position information are acquired by the new actuators and converted into corresponding protocols for the engine control unit. In the case of PWM actuators, internal errors occur, for example, if the H-bridge is too hot or the end stop cannot be reached, etc.The control line is pulled to ground for a specific period. The engine control unit can detect this information via the output stage diagnostics and interpret it accordingly. If the fault logs of the new regulated actuators and the old switched actuators are identical, then the corresponding information can be passed directly to the engine control unit. However, if the fault logs differ, then a corresponding adjustment should be made. Such an adjustment can also be stored in the characteristic maps.

[0122] The same applies to position feedback. If the engine control unit expects a position between, for example, 0 percent for closed and 100 percent for open, then it should receive this information. However, if, as in the example above, the new controlled actuators only implement 10 percent for closed and 80 percent for open, this information should not be forwarded to the engine control unit in this way, as this would otherwise trigger an error detection. An adjustment is necessary here as well. For the information feedback to the engine control unit, the auxiliary control unit (flap control unit) should, for example, generate 100 percent from the 0 percent position and 100 percent from the 80 percent position and report this position back to the engine control unit. This is necessary because otherwise the engine control unit's diagnostics would detect a fault.Position feedback will be an important topic in the future, and specifically for the use of OPF (Otto Particulate Filter), a stored exhaust system section should be diagnosable with regard to exhaust backpressure. Therefore, position feedback and its adjustment play a crucial role.

[0123] For retrofitted maps, it can also be important to feed back the corresponding position of the selected driving modes. Regardless of whether the driver activates Comfort, Sport, or Sport+ mode, exhaust flap 11, for example, can be operated using button 73 and thus adjusted, specifically opened or closed. The reason for this is that the engine control unit is unaware that the flap control unit, designed as an external control unit, is simulating flap control. If implausible position values ​​are returned, an error message can occur. It is likely advisable to directly report the adjustment request for the corresponding base maps. This may become necessary if a gasoline particulate filter (GPF) is used in the future. With this particulate filter, the exhaust back pressure is measured.To ensure plausible values ​​are generated, the exhaust flap control should be reproducible. The flap control unit can store data for multiple or different vehicles and exhaust systems in various configurations. These maps can be coded or programmed via hardware or software. In this way, a single auxiliary control unit could be used to operate different exhaust system and vehicle variants.

[0124] Overall, it is evident that conventional exhaust flaps can be replaced particularly easily and cost-effectively by exhaust flap 11 with the flap control unit, without requiring excessive modification or adaptation of the engine control unit. In particular, because exhaust flap 11 is designed as a regulated exhaust flap, precise level adjustment in the respective driving modes can be achieved, thus ensuring compatibility with artificial, internal sound systems. Specifically, with the help of an additional map (button map), exhaust flap 11 can be implemented with a control element such as button 73, allowing the driver, for example, to operate and, in particular, adjust or move the valve element 12 by pressing the control element.

[0125] Overall, it is evident that the auxiliary control unit can be connected between exhaust flap 11 and the engine control unit. The auxiliary control unit can simulate the interface hardware and protocols expected by the engine control unit regarding signal feedback and / or diagnostics. The base vehicle can have any known flap system, and the same can be true after the auxiliary control unit. Even a base vehicle without adjustable exhaust flaps can be operated by such a control unit because all control information can be accessed from the data bus. If necessary, the control unit can adjust the expected maps in the basic driving modes so that they are approximately identical to the standard configuration (i.e., for the areas where the interaction with active sound for the interior is crucial). The same applies to the homologation ranges and / or the areas where the exhaust backpressure must be correct.With an additional button, you can then focus solely on the approval ranges and / or the exhaust backpressure range. Variant coding even allows the maps to be varied for specific countries or different exhaust systems and vehicles. Maps don't require much storage space. The vehicle can then switch accordingly depending on the vehicle identification and coding.

[0126] In other words, the valve or auxiliary control unit is what allows aftermarket exhaust systems to be retrofitted and operated on a new vehicle. An aftermarket exhaust system typically has different exhaust outlet levels for the valve "off" and "closed" modes compared to a standard exhaust system. If these outlet levels were identical to the standard exhaust system, type approval with the given valve control would likely be possible. However, "identical levels" also means that such an exhaust system would no longer differ significantly from the standard system. The reason for the more difficult design of aftermarket exhaust systems is the new R51.03 external noise regulation and the existing exhaust valve control (in the engine control unit for the standard exhaust system), which aftermarket exhaust system manufacturers usually adopt or utilize.Another problem will be the use of particulate filters, which will soon be installed in gasoline engines. Specifically, the altered exhaust backpressure and the monitoring of the particulate filter. Another issue is the electronically based artificial acoustic enhancement in the vehicle. In the past, an advantage of an aftermarket exhaust system was not only the significantly more pronounced exterior sound, but also the ability to activate it independently via a separate switch or button. None of these points can be fulfilled with an aftermarket exhaust system in the future, at least not in the way it has been implemented so far. Reference symbol list 1 motor vehicle 2 Rear area 3 Internal combustion engine 4 Exhaust system 5 manifolds 6. Structure 7 Holding element 8 rear silencers 9 tailpipe 10 Environment 11 Exhaust flap 12 Valve element 13 Actuator 14 Mouth 15 Management 16 electronic computing equipment 17 length range 18 pipe section 19 Flow cross-section 20 Mounting bracket 21 Screw preparation 22 Thermal insulation / 23 Mounting tab 24 sleeve 25 plugs 26 connection 27 connection 28 connection 29 connection 30 cases 31 circuit boards 32 Electric motor 33 Rotor 34 Rotor shaft 35 Drive axle 36 Gear unit 37 Position detection 38 Position sensor 39 series rear silencers 40 Rear silencer housings 41 Exhaust pipe 42 branch 43 branch 44 Tailpipe opening 45 Abscissa 46 ordinates 47 Course 48 Course 49 Double Arrow 50 rear silencers 51 branch 52 branch 53 Course 54 Course 55 Exhaust flap 56 Control line 57 Feedback line 58 electronic computing equipment 59 Actuator 60 Course 61 Course 62 Course 63 Course 64 Storage device 65 map 66 Characteristic map 67 Characteristic map 68 Key map 69a-d map 70 microcontrollers 71 microcontrollers 72 microcontrollers 73 buttons 74 Management 75 Arrow 76 bus system 77 Current measurement 78 Wiring harness 79 plugs

Claims

[1] Method for operating an exhaust flap (11) for an exhaust system (4) of a motor vehicle (1) comprising an internal combustion engine (3) and at least one electronic computing device (16) for controlling the internal combustion engine (3), with at least one valve element (12), and with at least one actuator (13) by means of which the valve element (12) is moved, characterized by, that the exhaust flap (11) has its own electronic computing device (58) which receives at least one first signal provided by the electronic computing device (16) of the motor vehicle (1) and characterizing a first position of the valve element (12), generates at least one second signal depending on the received first signal, characterizing at least one second position of the valve element (12) different from the first position, and transmits the second signal to the actuator (13), whereby the valve element (12) is moved into the second position by means of the actuator (13). [2] Method according to claim 1, characterized by, that the valve element (12) is movable in an adjustment range which includes the second position and a plurality of further positions, wherein as a result of receiving the first signal the valve element (12) is moved into the positions of the adjustment range by means of its own electronic computing device (58) and by means of the actuator (13) and is held in the positions of the adjustment range. [3] Method according to claim 2, characterized by , that the valve element (12) is moved steplessly into respective positions of the adjustment range by means of its own electronic computing device (58) and by means of the actuator (13) and is held in the respective positions. [4] Method according to any one of the preceding claims, characterized by, that the vehicle's own electronic computing device (58) receives data provided by the electronic computing device (16) of the motor vehicle (1), which characterizes at least one state of the motor vehicle (1) different from the first position, and generates the second signal depending on the data received. [5] Method according to claim 4, characterized by , that the condition includes a rotational speed of the internal combustion engine (3) and / or a torque of the internal combustion engine (3) and / or a mass flow of an exhaust gas supplied by the internal combustion engine (3) and / or a position of an accelerator pedal of the motor vehicle (1) and / or a set driving mode of the motor vehicle (1) and / or a state of a control element (73) operable by a person for operating the exhaust flap (11). [6] Method according to any one of the preceding claims, characterized by, that in a storage device (64) of the own electronic computing device (58) at least one characteristic map (65) comprising the second position and several positions different from each other and from the second position is stored, wherein the own electronic computing device (58) selects one of the positions of the characteristic map (65) from the characteristic map (65) depending on the received first signal and causes a movement of the valve element (12) into the selected position by means of the actuator (13). [7] The method of claim 6 in reference to claim 4 or 5, characterized by , that the own electronic computing device (58) selects one of the positions of the characteristic map (65) from the characteristic map (65) depending on the data received and causes a movement of the valve element (12) to the selected position by means of the actuator (13). [8] Method according to any one of the preceding claims, characterized by, that the actuator (13) is designed as an electrically operable actuator. [9] Method according to any one of the preceding claims, characterized by , that by means of its own electronic computing device (58) at least the second position is detected, depending on the detection of the second position a feedback signal which characterizes the first position is generated and the feedback signal is provided to the electronic computing device (16) of the motor vehicle (1).

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