DEVICE AND METHOD FOR THE DIAGNOSTIC OF EGR VALVES

Abstract

Device for diagnosing an exhaust gas recirculation valve (EGR valve), comprising: an EGR device (40), comprising: an EGR line (41) connecting an exhaust line (30) and an intake line (60) of an engine (10), and an EGR valve (45) installed in the EGR line (41), an electric compressor (50) which is installed and set up in the inlet line (60) to change the internal pressure of an inlet manifold (70), an intake manifold pressure sensor (71) configured to measure the internal pressure of the intake manifold (70), and a control device (100) which is designed to learn the opening dimension of the EGR valve (45) and to diagnose a stuck EGR valve (45) and a leak in the EGR valve (45) when the engine (10) is switched off while the vehicle is moving, based on the measured internal pressure in the intake manifold (70).

Description

AREA

[0001] The present disclosure relates to a device and a method for diagnosing an EGR valve. BACKGROUND

[0002] The statements in this section merely provide background information in connection with the present disclosure and may not represent prior art.

[0003] An exhaust gas recirculation (EGR) system is used in vehicles to reduce harmful exhaust emissions. Generally, the proportion of NOx in the exhaust gas increases when the air-fuel ratio is high. Therefore, the EGR system recirculates a portion (e.g., 5 to 20%) of the exhaust gas expelled from the engine back into the air-fuel mixture to reduce the oxygen concentration and thus suppress NOx formation by disrupting combustion.

[0004] Typically, an exhaust gas recirculation (EGR) system recirculates exhaust gas that is expelled from the engine cylinders through an exhaust manifold and flows back to the engine cylinders via an exhaust pipe. This recirculation is achieved through a recirculation line, also known as an EGR line. An EGR valve is typically installed in the EGR line to regulate the EGR ratio.

[0005] The exhaust gas recirculation system can be divided into a low-pressure EGR device and a high-pressure EGR device.

[0006] The high-pressure EGR system directs the recirculated gas (EGR gas) from the exhaust manifold to the intake manifold under high pressure. The low-pressure EGR system directs the EGR gas from a downstream side of an exhaust aftertreatment system in the exhaust pipe to an upstream side of a turbocharger / supercharger compressor in the intake pipe.

[0007] In such a conventional exhaust gas recirculation system, the exhaust gas circulates through an EGR line that branches off from the exhaust pipe and is connected to the intake pipe. The EGR line is equipped with an EGR cooler to cool the recirculated exhaust gas and an EGR valve to regulate the amount of recirculated exhaust gas.

[0008] We have found that the actual amount of EGR controlled by the opening of the EGR valve is difficult to determine, and that a method is needed that can accurately predict or diagnose the operation and opening of the EGR valve in order to improve NOx control.

[0009] The above-mentioned information disclosed in this "Background" section is intended only to improve the understanding of the background of the present disclosure and may therefore contain information that is not part of the prior art already known to the person skilled in the art.

[0010] For example, a device and a method are known from KR 102 014 178 B1 in which an exhaust gas recirculation valve can be diagnosed using an electric compressor even when the engine is switched off. The device comprises an exhaust gas recirculation valve for recirculating exhaust gas from an exhaust manifold into an intake manifold, an electric compressor for compressing the ambient air supplied by the air filter, a pressure sensor for detecting pressure in the intake manifold, and a control unit for operating the electric compressor when a preset diagnostic condition is met. BRIEF EXPLANATION

[0011] The present disclosure provides a device for diagnosing an EGR valve and a method for using the same, which have the advantage of accurately diagnosing the normal operation and opening of the EGR valve of the exhaust gas recirculation device.

[0012] An exemplary device for diagnosing an EGR valve comprises: an exhaust gas recirculation device with an EGR line connecting an exhaust pipe and an intake pipe of an internal combustion engine (hereinafter also referred to as: engine), and an EGR valve installed in the EGR line; an electric supercharger (e.g., an electrically driven compressor) installed in the intake pipe and configured to change the internal pressure of an intake manifold; an intake manifold pressure sensor measuring the internal pressure of the intake manifold; and a control device configured to determine an opening dimension or amount (e.g., an opening angle; hereinafter also referred to as: opening dimension, dimension, or amount) of the EGR valve when the engine is switched off while the vehicle is moving, running, or in operation (hereinafter referred to as: moving); and a fixing device (e.g., a locking mechanism).to diagnose a jamming) of the EGR valve and a leakage of the EGR valve based on the measured internal pressure of the intake manifold, which varies depending on the opening dimension of the EGR valve.

[0013] The control device can be set up, for example, to learn the opening dimension of the EGR valve, to diagnose the fixity of the EGR valve and the leakage of the EGR valve after positioning a crank angle in a reference position with the engine stationary.

[0014] In one embodiment, for example, the control device can operate the electric supercharger in a positive direction (e.g., overpressure generation) to generate a positive pressure above atmospheric pressure in the intake manifold, open the EGR valve for a first predetermined period with a first predetermined opening dimension, and then close the EGR valve when the first predetermined period has elapsed, and calculate a first pressure difference by comparing an internal pressure of the intake manifold measured during the first predetermined period with a first reference pressure (e.g., a pressure stored in a map), so that the control device learns the opening dimension of the EGR valve.

[0015] In another embodiment, the control device can, for example, be configured to: open the EGR valve for a second predetermined period with a second predetermined opening dimension and then close the EGR valve after the second predetermined period has elapsed, wherein the second predetermined opening dimension differs from the first predetermined opening dimension; calculate a second pressure difference by comparing an internal pressure of the intake manifold measured during the second predetermined period with a second reference pressure (e.g., a pressure stored in a characteristic map); calculate a ratio of the first pressure difference to the second pressure difference; and determine a compensation value for the opening of the EGR valve based on the calculated ratio of the first pressure difference to the second pressure difference.

[0016] The control device can be configured to determine that the EGR valve is fixed or locked when the internal pressure of the intake manifold, as detected by the intake manifold pressure sensor, is not changed while the electric supercharger is operated in the positive direction to create an overpressure above atmospheric pressure in the intake manifold, and to send an instruction to open the EGR valve with different opening dimensions.

[0017] The control device can be configured, for example, to detect that the EGR valve has a leak if the internal pressure in the intake manifold, as detected by the intake manifold pressure sensor, deviates from a reference pressure by more than a predetermined pressure while the electric supercharger is operated in a positive direction to generate a positive pressure above atmospheric pressure in the intake manifold, and to send an instruction to open the EGR valve with different opening dimensions.

[0018] The control device can be set up, for example, to learn the opening of the EGR valve by operating the electric supercharger in reverse direction (e.g., vacuum generation direction) to create a vacuum below atmospheric pressure in the intake manifold, closing the EGR valve for a first predetermined period until a first predetermined opening dimension is reached after the EGR valve has opened, and comparing the internal pressure of the intake manifold with a first reference pressure.

[0019] The control device can, for example, be configured to send an instruction to close the EGR valve after it has sent an instruction to open the EGR valve to a second predetermined opening dimension, which differs from the first predetermined opening dimension, for a first predetermined period, and compares the internal pressure of the intake manifold with a second reference pressure, and determine a compensation value for the opening of the EGR valve as a ratio of a differential pressure between the first reference pressure and the internal pressure of the intake manifold, which is measured when an instruction to open the EGR valve to the first predetermined opening dimension is sent, and determine a differential pressure between the second reference pressure and the internal pressure of the intake manifold, which is measured when an instruction to open the EGR valve to the second predetermined opening dimension is sent.

[0020] The control device can be configured, for example, to lock the EGR valve when the internal pressure of the intake manifold, as detected by the intake manifold pressure sensor, is not changed, while the electric supercharger is operated in reverse to create a vacuum below atmospheric pressure in the intake manifold, and to send an instruction to open the EGR valve with different opening dimensions.

[0021] The control device can be set up, for example, to detect when the EGR valve has a leak, when the internal pressure in the intake manifold detected by the intake manifold pressure sensor deviates from a reference pressure by more than a predetermined pressure, while the electric supercharger is operated in reverse to create a vacuum below atmospheric pressure in the intake manifold, and send an instruction to open the EGR valve with different opening dimensions.

[0022] An exemplary method for diagnosing an EGR valve provided in an exhaust gas recirculation device includes: determining, by a control device, whether an engine is stopped while a vehicle is in motion; operating an electric supercharger by the control device; detecting an internal pressure of an intake manifold by an intake manifold pressure sensor corresponding to an opening of the EGR valve; and learning the opening of the EGR valve by the control device from the internal pressure of the intake manifold detected by the intake manifold pressure sensor.

[0023] The exemplary procedure may, for example, further include operating the electric supercharger in a positive direction to generate a positive pressure above atmospheric pressure in the intake manifold, sending an instruction to open the EGR valve for a predetermined period up to a first predetermined amount, sending an instruction to close the EGR valve, and learning the opening of the EGR valve by comparing the internal pressure of the intake manifold with a first reference pressure.

[0024] The exemplary procedure may further include, for example: sending an instruction to open the EGR valve for a predetermined period up to a second predetermined amount that differs from the first predetermined amount; sending an instruction to close the EGR valve and comparing the internal pressure of the intake manifold with a second reference pressure; and determining a compensation value for the opening of the EGR valve as a ratio of a differential pressure between the first reference pressure and the internal pressure of the intake manifold, measured when an instruction to open the EGR valve is sent to the first predetermined amount, and a differential pressure between the second reference pressure and the internal pressure of the intake manifold, measured when an instruction to open the EGR valve is sent to the second predetermined amount.

[0025] The exemplary procedure may, for example, further include operating the electric supercharger in reverse to generate a vacuum below atmospheric pressure in the intake manifold, sending an instruction to open the EGR valve for a predetermined period up to a first predetermined amount, sending an instruction to close the EGR valve, and learning to open the EGR valve by comparing the internal pressure of the intake manifold with a first reference pressure.

[0026] The exemplary procedure may, for example, further include sending an instruction to open the EGR valve for a predetermined period to a second predetermined amount that differs from the first predetermined amount, sending an instruction to close the EGR valve and comparing the internal pressure of the intake manifold with a second reference pressure, and determining a compensation value for the opening of the EGR valve as a ratio of a differential pressure between the first reference pressure and the internal pressure of the intake manifold, measured when an instruction to open the EGR valve to the first predetermined amount is sent, and a differential pressure between the second reference pressure and the internal pressure of the intake manifold, measured when an instruction to open the EGR valve to the second predetermined amount is sent.

[0027] Another exemplary method for diagnosing an EGR valve provided in an exhaust gas recirculation device includes: Determining, by a control device, whether an engine is off and a diagnostic request condition and a learning availability condition are met; operating an electric supercharger by the control device; detecting an intake manifold internal pressure by an intake manifold pressure sensor corresponding to an EGR valve opening; determining whether the EGR valve is locked by the control device from the intake manifold internal pressure detected by the intake manifold pressure sensor; operating the electric supercharger in reverse to create a vacuum below atmospheric pressure in the intake manifold; sending an instruction to open the EGR valve to an opening of a different size; stopping the electric supercharger.Sending a command to close the EGR valve and determining that the EGR valve is stuck (e.g., jammed) when the intake manifold internal pressure, as detected by the intake manifold pressure sensor, remains unchanged, if a command to open the EGR valve to an opening of a different size is sent. The exemplary procedure may further include, for example: operating the electric supercharger in the positive direction to generate an overpressure above atmospheric pressure in the intake manifold, sending a command to open the EGR valve to an opening of a different size, stopping the electric supercharger, sending a command to close the EGR valve, and determining that the EGR valve is stuck when the intake manifold internal pressure, as detected by the intake manifold pressure sensor, remains unchanged, if a command to open the EGR valve to an opening of a different size is sent.

[0028] Another exemplary procedure for diagnosing an EGR valve provided in an exhaust gas recirculation device includes: Determining, by the control device, whether an engine is off and a diagnostic request condition and a learning availability condition are met; operating an electric supercharger, by the control device; detecting an intake manifold internal pressure by an intake manifold pressure sensor corresponding to an EGR valve opening; determining an EGR valve leak, by the control device, from the intake manifold internal pressure detected by the intake manifold pressure sensor; operating the electric supercharger in reverse to create a vacuum below atmospheric pressure in the intake manifold; sending an instruction to open the EGR valve to an opening of a different size; stopping the electric supercharger.Sending an instruction to close the EGR valve and determining that the EGR valve has a leak if the internal pressure of the intake manifold, as detected by the intake manifold pressure sensor, deviates from a reference pressure by more than a predetermined pressure.

[0029] The exemplary procedure may further include, for example: operating the electric supercharger in a positive direction to generate an overpressure above atmospheric pressure in the intake manifold, sending a command to open the EGR valve to an opening of a different size, stopping the electric supercharger, sending a command to close the EGR valve, and determining that the EGR valve has a leak if the internal pressure of the intake manifold, as detected by the intake manifold pressure sensor, deviates from a reference pressure by more than a predetermined pressure.

[0030] According to a device for diagnosing an EGR valve and a method for diagnosing an EGR valve according to an exemplary embodiment, normal and abnormal operation and the opening of the EGR valve can be accurately diagnosed by operating an electric supercharger to measure the internal pressure of an intake manifold corresponding to the opening of the EGR valve.

[0031] Further areas of application will become apparent from the description given here. It should be understood that the description and the specific examples serve only for illustration and are not intended to limit the scope of this disclosure. DRAWINGS

[0032] To better understand the revelation, various embodiments thereof are now described, with reference to the accompanying drawings as examples, in which: Fig. 1 a schematic representation of an engine system that can be used in a device for diagnosing an EGR valve in an exemplary embodiment of the present disclosure, Fig. 2 is a block diagram representing a configuration of a device for diagnosing an EGR valve in an exemplary embodiment of the present disclosure, Fig. 3 a method for setting a crank angle in a device for diagnosing an EGR valve in an exemplary embodiment of the present disclosure shows, Fig. 4 is a flowchart showing a method for diagnosing an EGR valve in an exemplary embodiment of the present disclosure, Fig. 5 a drawing to illustrate a method for learning an EGR measure corresponding to the opening of an EGR valve in an exemplary embodiment of the present disclosure is, Fig. 6 a drawing illustrating a method for diagnosing a fixation of an EGR valve in an exemplary embodiment of the present disclosure is, Fig. 7 a drawing illustrating a method for diagnosing a leakage of an EGR valve in an exemplary embodiment of the present disclosure is, Fig. 8 a drawing to illustrate a method for diagnosing and learning an EGR measure corresponding to the opening of an EGR valve in a further exemplary embodiment of the present disclosure is, Fig. 9 a drawing illustrating a method for diagnosing a fixation of an EGR valve in a further exemplary embodiment of the present disclosure, and Fig. 10 is a drawing illustrating a method for diagnosing a leakage of an EGR valve in a further exemplary embodiment of the present disclosure.

[0033] The drawings described here are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. DETAILED DESCRIPTION

[0034] The following description is merely exemplary and is not intended to limit the present disclosure, application, or use. It should be understood that throughout the drawings, corresponding reference numerals indicate similar or corresponding parts and features.

[0035] The present disclosure is described in more detail below with reference to the accompanying drawings, which show exemplary embodiments of the present disclosure. As is clear to those skilled in the art, the described embodiments can be modified in various ways without deviating from the scope of the present disclosure.

[0036] To illustrate the present revelation, parts not related to the description are omitted.

[0037] Although the size and thickness of the individual elements in the drawings are arbitrarily indicated, the present disclosure is not necessarily limited thereto, and the thicknesses of the layers, films, plates, areas, etc. are exaggerated in the drawings for the sake of clarity.

[0038] A device for diagnosing an EGR valve is described in detail below in exemplary embodiments of the present disclosure with reference to the drawings.

[0039] Fig. Figure 1 is a schematic representation of an internal combustion engine system in which a device for diagnosing an EGR valve can be used in an exemplary embodiment of the present disclosure. Furthermore, Fig. 2 a block diagram showing a configuration of a device for diagnosing an EGR valve in an embodiment of the present disclosure.

[0040] First, the internal combustion engine system in which the device for diagnosing the EGR valve can be used in an embodiment of the present disclosure is described in detail. A vehicle that can be used with the device for diagnosing an EGR valve can be a vehicle that has only an internal combustion engine, or it can be a hybrid vehicle that has both an internal combustion engine and, for example, an electric drive motor.

[0041] As in Fig. 1 and Fig. Figure 2 shows a drive system in an embodiment of the present disclosure comprising: an engine 10 with multiple combustion chambers which generate a drive torque by burning fuel, an inlet line 60 which receives an intake air supplied to the combustion chamber, a throttle valve 64 which is arranged on an upstream side of an inlet manifold 70 and which regulates the amount of air supplied to the combustion chamber, an electric supercharger 50 which is arranged on an upstream side of the throttle valve 64 in the inlet line 60 and which comprises a motor 51 and an electric compressor 53 which is driven by the motor 51 to supply compressed air to the combustion chamber, a catalyst 80 which cleans the exhaust gas expelled from the combustion chamber, and an exhaust gas recirculation device (EGR device) 40 which returns a portion of the exhaust gas expelled from the combustion chamber to the combustion chamber.

[0042] The electric supercharger 50, which supplies the combustion chamber with compressed air, comprises the motor 51 and the electric compressor 53. The electric compressor 53 is driven by the motor 51 and compresses ambient air according to the driving conditions to supply compressed air to the combustion chamber.

[0043] The inlet line 60 is provided with a bypass line 62, which diverts a portion of the air supplied to the electric compressor 50. A bypass valve 63 is attached to the bypass line 62. The amount of air supplied to the electric compressor 50 is regulated by the bypass valve 63.

[0044] The exhaust gas recirculation device 40 has an EGR line 41 through which a part (recirculation gas) of the exhaust gas expelled from the combustion chamber flows, an EGR cooler 43 installed in the EGR line 41 and an EGR valve 45 for adjusting an EGR gas quantity.

[0045] The EGR line 41 branches off from the exhaust line 30 on a downstream side of the catalyst 80 for the exhaust gas generated in the combustion chamber and is connected to the inlet line 60 on a downstream side of the electric charger 50 installed in the inlet line 60.

[0046] The EGR cooler 43 cools the recirculation gas (EGR gas) flowing through the EGR line 41 and supplies the cooled gas to the combustion chamber.

[0047] An engine system according to an exemplary embodiment can be used in a hybrid vehicle with, for example, an electric drive motor 110, which supports the power of the engine 10.

[0048] The drive motor 110 assists the power of the motor 10 and selectively operates as a generator to produce electrical energy. The drive motor 110 is powered by electrical energy stored in a battery (not shown). The electrical energy generated by the drive motor 110 is charged into the battery.

[0049] A data acquisition unit 90 acquires various data used for a procedure to diagnose an EGR valve, based on a pattern, and sends the acquired data to a control device 100.

[0050] The data acquired by the data acquisition unit 90 can include an internal pressure of an intake manifold, a crankshaft angle, a coolant temperature, and a stop signal from the engine.

[0051] For this purpose, the data acquisition unit 90 can include an intake manifold pressure sensor (MAP sensor: manifold absolute pressure sensor) 71 for detecting the internal pressure of an intake manifold, a crank angle position sensor (crank angle position sensor) for detecting the crankshaft angle, and a coolant temperature sensor for detecting the coolant temperature.

[0052] Furthermore, the engine stop state can include an ignition key off stop, an engine stall stop, and an idle stop. In one embodiment, the data acquisition unit 90 can include an ignition key sensor for detecting the ignition key off stop, a speed sensor for detecting the engine stall stop, and / or an accelerator pedal sensor and a brake pedal sensor for detecting the idle stop.

[0053] The control device 100 controls the electric supercharger 50 based on the data acquired by the data acquisition unit 90 and learns an opening dimension of the EGR valve 45 from the internal pressure of the intake manifold. The control device can detect a stuck EGR valve 45 and a leakage of the EGR valve 45 based on the acquired data.

[0054] For this purpose, the control device 100 can be provided as at least one processor which can be operated by a predetermined program, wherein the predetermined program can contain instructions for the respective steps of a method for diagnosing the EGR valve 45 according to an exemplary embodiment of the present disclosure.

[0055] The following describes in detail a method for diagnosing an EGR valve using an exemplary embodiment with reference to the drawings.

[0056] Fig. Figure 4 is a flowchart showing a method for diagnosing an EGR valve according to an exemplary embodiment of the present disclosure.

[0057] As in Fig. As shown in Figure 4, the control device 100 first determines in step S10, based on the data recorded by the data acquisition unit 90, whether the motor is stopped / has stopped.

[0058] If the engine is switched off while the vehicle is running or moving (S10-Yes), the control device 100 determines in step S20 whether a diagnostic request condition and a learning availability condition of the EGR valve 45 are met.

[0059] The diagnostic request condition can mean that the control device 100 has not diagnosed the EGR valve 45 for a predetermined period. The diagnostic request condition can be met, for example, if the vehicle's engine is started after being parked for an extended period (e.g., more than 6 hours) or if the EGR valve 45 has not been diagnosed for an extended period (e.g., 5 to 6 hours) while the vehicle is in motion.

[0060] The learning availability condition is used to determine whether the EGR valve is in a state unsuitable for diagnosis. It can be configured that the learning availability condition is not met if the coolant temperature is below a predetermined temperature (e.g., 60 degrees Celsius), if the battery voltage is below a predetermined value (e.g., 11 V), if an electrical signal from a major component (e.g., MAP sensor, EGR valve, or similar) is abnormal (e.g., short circuit or similar), if the atmospheric pressure is below a predetermined pressure (e.g., 950 hpa), if the ambient air temperature is below a predetermined temperature (e.g., -30 degrees Celsius), if a misfire occurs in the engine or a major component such as a catalytic converter is damaged, if a driver is not wearing a seatbelt, or if the hood or a car door is open.

[0061] If the diagnostic request condition and the learning availability condition are met (S20-Yes), the control device 100 adjusts the position of a crankshaft 19 by means of the drive motor 110 and / or the throttle valve 64 so that the crankshaft angle is positioned in a reference position. At this point, the reference position can be set as a position at which the valve overlap of an intake valve 15 and an exhaust valve 17 of a corresponding cylinder is / is minimal (see Fig. 3; e.g., inlet and outlet valve(s) are closed).

[0062] Subsequently, in step S30, the control device 100 operates the electric supercharger, e.g., in the positive direction, to generate an overpressure above atmospheric pressure in the intake manifold 70. Then, in step S40, the control device 100 sends an instruction, e.g., to open the EGR valve 45 for a predetermined period up to a first predetermined amount, and then generates a control signal, e.g., to close the EGR valve 45. At this point, the bypass valve 63 may be closed.

[0063] Alternatively, the control device 100 can generate a control signal before closing the EGR valve 45 to further open the EGR valve 45 up to a second predetermined amount that differs from the first predetermined amount.

[0064] Then, in step S60, the control device 100 learns an opening dimension of the EGR valve 45 from the internal pressure of the intake manifold 70 or diagnoses a fixation of the EGR valve 45 and / or a leakage of the EGR valve 45.

[0065] Furthermore, in step S70, if a fix and / or a leak is diagnosed at the EGR valve 45, the control device 100 can warn a driver about the condition of the EGR valve 45 via a center console or similar device.

[0066] The process of learning how to open the EGR valve 45 is described in more detail.

[0067] Fig. Figure 5 is an explanatory drawing showing a method for learning about an EGR quantity after opening the EGR valve 45 according to an exemplary embodiment. Fig. 5 is the horizontal axis a time axis, the left vertical axis is the internal pressure of the intake manifold 70 and the right vertical axis is the opening of the EGR valve 45.

[0068] With reference to Fig. 5: While the control device 100 has generated a control signal to close the EGR valve 45 when the electric supercharger is operating in the positive direction, the internal pressure of the intake manifold 70 varies depending on the opening degree of the EGR valve 45. At this point, the reference pressure is the internal pressure of the intake manifold 70 in the case that the EGR valve 45 ideally follows the control signal of the control device 100.

[0069] This means that if the EGR valve 45 normally follows the control signal from the control device 100, when a control signal is generated to operate the electric supercharger 50 and to close the EGR valve 45, the internal pressure in the intake manifold 70 will rise to a positive pressure above atmospheric pressure (see “A” in Fig. 5) When a control signal is generated to open the EGR valve 45 to the first predetermined amount, the internal pressure of the intake manifold 70 becomes a positive pressure, which is lower than when the EGR valve 45 is closed (see “B” in Fig. 5) In addition, if a control signal is generated to open the EGR valve 45 to a second predetermined amount that is greater than the first predetermined amount, the internal pressure of the intake manifold 70 becomes a positive pressure that is lower than when the EGR valve 45 is opened to the first predetermined amount (see “C” in Fig. 5) Finally, when the EGR valve 45 is closed and the electric supercharger 50 is stopped, the internal pressure in the intake manifold 70 is maintained at atmospheric pressure (see “D” in Fig. 5).

[0070] However, if the EGR valve 45 does not precisely follow the control signal from the control device 100, the internal pressure in the intake manifold 70 deviates from the reference pressure. That is, if the control device 100 has generated a control signal to open to the first predetermined amount, and the internal pressure of the intake manifold 70 measured by the intake manifold pressure sensor 71 deviates from the reference pressure, it can be determined that the EGR valve 45 is not precisely following the control signal from the control device 100.

[0071] Therefore, the control device 100 generates a control signal to open the EGR valve 45 for a predetermined period to a second predetermined amount that differs from the first predetermined amount, and compares the internal pressure of the inlet manifold 70 with the reference pressure.

[0072] Furthermore, the control device 100 can determine a compensation value for the opening of the EGR valve 45 as a ratio of differential pressures, i.e., as a ratio between a differential pressure between the reference pressure and the internal pressure of the intake manifold 70, which was measured when the control device 100 generated a control signal to open the EGR valve 45 to the first predetermined amount, and a differential pressure between the reference pressure and the internal pressure of the intake manifold 70, which was measured when the control device 100 generated a control signal to open the EGR valve 45 to the second predetermined amount.

[0073] Here, an EGR amount (e.g., an actual amount of EGR that can be traced back due to the function of the EGR valve) can be calculated using the following equation. EGR amount = effective cross-sectional area of ​​the EGR line * compensation value * pressure difference between the upstream and downstream sides of the EGR valve * flow function * temperature of the EGR gas

[0074] By adjusting the compensation value of the EGR valve opening in equation 1 to the ratio of the differential pressures, the control device 100 can accurately calculate the EGR amount.

[0075] A method for diagnosing EGR valve fixation is described in detail using an exemplary embodiment.

[0076] Fig. Figure 6 is a drawing illustrating a method for diagnosing a stuck EGR valve using an exemplary embodiment. Fig. 6 is the horizontal axis a time axis, the left vertical axis is the internal pressure of the intake manifold 70 and the right vertical axis is the opening of the EGR valve.

[0077] With reference to Fig. 6 The control device 100 has generated a control signal to close the EGR valve 45, while the control device 100 operates the electric supercharger 50 in the positive direction to generate a positive pressure above atmospheric pressure in the intake manifold 70 (see “A” in Fig. 6). At this point, the bypass valve 63 is closed.

[0078] Additionally, the control device 100 generates a control signal to open the EGR valve 45 to a different opening size (i.e., different opening widths). For example, after generating a control signal to open the EGR valve 45, the control device 100 can open it to the first predetermined opening dimension (see “B” in Figure 1). Fig. 6) generate a control signal to open the EGR valve 45 to the second predetermined opening dimension, which is larger than the first predetermined opening dimension (see “C” in Fig. 6).

[0079] The control device 100 then generates a control signal to close the EGR valve 45 and then stops the electric turbocharger 50 (see “D” in Fig. 6).

[0080] If the internal pressure in the intake manifold 70 measured by the intake manifold pressure sensor does not vary, even though the control signal to open the EGR valve 45 to a different size is generated, the control device 100 can determine that the EGR valve 45 is stuck (i.e. jammed, e.g. stuck closed).

[0081] Therefore, the control device 100 can inform the driver, e.g. by means of an alarm or similar via a center console or similar installed in the vehicle, that the EGR valve 45 has a fault.

[0082] A method for diagnosing a leak in the EGR valve is described in detail using an exemplary embodiment.

[0083] Fig. Figure 7 is a drawing illustrating a method for diagnosing an EGR valve leak using an exemplary embodiment. Fig. 7 is the horizontal axis, a time axis; the left vertical axis is the internal pressure of the intake manifold 70; and the right vertical axis is the opening of the EGR valve.

[0084] With reference to Fig. 7 The control device 100 has generated a control signal to close the EGR valve 45, while the control device 100 operates the electric supercharger 50 in the positive direction to generate a positive pressure above atmospheric pressure in the intake manifold 70 (see “A” in Fig. 7).

[0085] Additionally, the control device 100 generates a control signal to open the EGR valve 45 to a different opening size. For example, after generating a control signal to open the EGR valve 45 to the first predetermined amount (see “B” in Figure 100), the control device 100 can open the EGR valve 45 to the first predetermined amount. Fig. 7) generate a control signal to open the EGR valve 45 to the second predetermined amount, which is greater than the first predetermined amount (see “C” in Fig. 7).

[0086] The control device 100 then generates a control signal to close the EGR valve 45 and then stops the electric turbocharger 50 (see “D” in Fig. 7).

[0087] If the internal pressure of the intake manifold 70 detected by the intake manifold pressure sensor deviates from the reference pressure by more than a predetermined pressure while the electric supercharger 50 is operated and the EGR valve 45 is controlled to open, the control device 100 can determine that the EGR valve 45 is leaking.

[0088] Therefore, the control device 100 can inform the driver, e.g. by means of an alarm or similar via a center console or similar installed in the vehicle, that the EGR valve 45 has a fault.

[0089] The following describes in detail a procedure for learning how to open the EGR valve, diagnose the fixation, and diagnose the leakage according to another exemplary embodiment.

[0090] A method for learning the opening (e.g., the opening dimension) of the EGR valve is described in detail.

[0091] Fig. Figure 8 is a drawing illustrating a method for diagnosing and determining the EGR quantity according to the opening of the EGR valve 45 according to a further exemplary embodiment. Fig. 8 is the horizontal axis a time axis, the left vertical axis is the internal pressure of the intake manifold 70 and the right vertical axis is the opening of the EGR valve 45.

[0092] With reference to Fig. 8. While the control device 100 has generated a control signal to close the EGR valve 45, the internal pressure of the intake manifold 70 varies according to the opening of the EGR valve 45 when the electric supercharger 50 operates in reverse. At this point, the reference pressure is the internal pressure of the intake manifold 70 as if the EGR valve 45 were perfectly responding to the control signal from the control device 100.

[0093] This means that if the EGR valve 45 normally follows the control signal from the control device 100, when a control signal is generated to operate the electric supercharger 50 and to close the EGR valve 45, the internal pressure in the intake manifold 70 will become a vacuum below atmospheric pressure (see “A” in Fig. 8) When a control signal is generated to open the EGR valve 45 to the first predetermined amount, the internal pressure of the intake manifold 70 becomes a vacuum that is higher than when the EGR valve 45 is closed (see “B” in Fig. 8) In addition, if a control signal is generated to open the EGR valve 45 to a second predetermined amount greater than the first predetermined amount, the internal pressure of the intake manifold 70 becomes a vacuum greater than when the EGR valve 45 is opened to the first predetermined amount (see “C” in Fig. 8) Finally, when the EGR valve 45 is closed and the electric supercharger 50 is stopped, the internal pressure in the intake manifold 70 is maintained at atmospheric pressure (see “D” in Fig. 8).

[0094] However, if the EGR valve 45 does not precisely follow the control signal from the control device 100, the internal pressure in the intake manifold 70 deviates from the reference pressure. That is, if the control device 100 has generated a control signal to open the first predetermined amount when the internal pressure in the intake manifold 70, measured by the intake manifold pressure sensor, deviates from the reference pressure, it can be concluded that the EGR valve 45 is not precisely following the control signal from the control device 100.

[0095] The control device 100 generates a control signal to open the EGR valve 45 for a predetermined period to a second predetermined amount that differs from the first predetermined amount, and compares the internal pressure of the inlet manifold 70 with the reference pressure.

[0096] Furthermore, the control device 100 can determine a compensation value for the opening of the EGR valve 45 based on a ratio of differential pressures, i.e., a ratio between a differential pressure between the reference pressure and the internal pressure of the intake manifold 70, which was measured when the control device 100 generated a control signal to open the EGR valve 45 to the first predetermined opening dimension, and a differential pressure between the reference pressure and the internal pressure of the intake manifold 70, which was measured when the control device 100 generated a control signal to open the EGR valve 45 to the second predetermined opening dimension.

[0097] An EGR amount (e.g., an actual amount of EGR that can be traced back due to the function of the EGR valve) can be calculated using the following equation. EGR amount = effective cross-sectional area of ​​the EGR line * compensation value * pressure difference between the upstream and downstream sides of the EGR valve * flow function * temperature of the EGR gas

[0098] By adjusting the compensation value of the EGR valve opening in equation 1 to the ratio of the differential pressures, the control device 100 can accurately calculate the EGR amount.

[0099] A method for diagnosing the fixation of the EGR valve according to a further exemplary embodiment is described in detail.

[0100] Fig. Figure 9 is a drawing illustrating a method for diagnosing a stuck EGR valve using an exemplary embodiment. Fig. 9 is the horizontal axis a time axis, the left vertical axis is the internal pressure of the intake manifold 70 and the right vertical axis is the opening of the EGR valve.

[0101] With reference to Fig. 9: While the control device 100 has generated a control signal to close the EGR valve 45, the control device 100 actuates the electric compressor 50 in the reverse direction to generate a vacuum below atmospheric pressure in the intake manifold 70 (see “A” in Fig. 9).

[0102] Additionally, the control device 100 generates a control signal to open the EGR valve 45 to a different opening size. For example, after generating a control signal to open the EGR valve 45 to the first predetermined amount (see “B” in Figure 100), the control device 100 can open the EGR valve 45 to the first predetermined amount. Fig. 9) generate a control signal to open the EGR valve 45 to the second predetermined amount, which is greater than the first predetermined amount (see “C” in Fig. 9).

[0103] The control device 100 then generates a control signal to close the EGR valve 45 and then stops the electric turbocharger 50 (see “D” in Fig. 9).

[0104] If the internal pressure in the intake manifold 70 measured by the intake manifold pressure sensor does not vary, even though the control signal to open the EGR valve 45 to a different size is generated, the control device can determine that the EGR valve 45 is stuck.

[0105] Therefore, the control device 100 can inform the driver, e.g. by means of an alarm or similar via a center console or similar installed in the vehicle, that the EGR valve 45 has a fault.

[0106] A method for diagnosing a leakage of the EGR valve according to a further exemplary embodiment is described in detail.

[0107] Fig. Figure 10 is a drawing illustrating a method for diagnosing an EGR valve leak using an exemplary embodiment. Fig. 10 is the horizontal axis a time axis, the left vertical axis is the internal pressure of the intake manifold 70 and the right vertical axis is the opening of the EGR valve.

[0108] With reference to Fig. 10 The control device 100 has generated a control signal to close the EGR valve 45, while the control device 100 operates the electric supercharger 50 in the reverse direction to generate a vacuum below atmospheric pressure in the intake manifold 70 (see “A” in Fig. 10).

[0109] Additionally, the control device 100 generates a control signal to open the EGR valve 45 to a different opening size. For example, after generating a control signal to open the EGR valve 45 to the first predetermined amount (see “B” in Figure 100), the control device 100 can open the EGR valve 45 to the first predetermined amount. Fig. 10) generate a control signal to open the EGR valve 45 to the second predetermined amount, which is greater than the first predetermined amount (see “C” in Fig. 10).

[0110] The control device 100 then generates a control signal to close the EGR valve 45 and then stops the electric turbocharger 50 (see “D” in Fig. 10).

[0111] If the internal pressure of the intake manifold 70, as detected by the intake manifold pressure sensor, deviates from the reference pressure by more than a predetermined pressure while the electric supercharger 50 is operating and the EGR valve 45 is controlled to open, the control device 100 can detect that the EGR valve 45 is leaking.

[0112] Therefore, the control device 100 can inform the driver, e.g. by means of an alarm or similar via a center console or similar installed in the vehicle, that the EGR valve 45 has a fault.

[0113] While the present disclosure has been described in connection with the embodiments currently considered practical, it is clear that the present disclosure is not limited to the disclosed embodiments. On the contrary, various modifications and equivalent arrangements are covered, which are included in the scope of the appended claims. REFERENCE MARK LIST 10 Motor 11 Combustion chamber 15 Inlet valve 17 Exhaust valve 30 Exhaust pipe 35 exhaust manifold 40 Exhaust gas recirculation device 41 EGR line 43 EGR cooler 45 EGR valve 50 electric chargers 51 Engine 53 electric compressor 60 Admission line 62 Bypass line 63 Bypass valve 64 Throttle valve 68 air filters 70 Intake manifold 71 Intake manifold pressure sensor 80 catalyst 90 Data acquisition unit 100 Control device 110 Drive motor

Claims

Device for diagnosing an exhaust gas recirculation valve (EGR valve), comprising: an EGR device (40), comprising: an EGR line (41) connecting an exhaust line (30) and an intake line (60) of an engine (10), and an EGR valve (45) installed in the EGR line (41), an electric compressor (50) installed in the intake line (60) and configured to change the internal pressure of an intake manifold (70), an intake manifold pressure sensor (71) configured to measure the internal pressure of the intake manifold (70), and a control device (100) configured to, when the engine (10) is switched off while the vehicle is in motion, learn the opening dimension of the EGR valve (45) based on the measured internal pressure in the intake manifold (70) and to fix the EGR valve (45) and to diagnose a leak in the EGR valve (45). Device according to claim 1, wherein the control device (100) is configured to detect the opening dimension of the EGR valve (45), to diagnose the fixity of the EGR valve (45) and the leakage of the EGR valve (45) after positioning a crank angle in a reference position when the engine (10) is switched off. Device according to claim 1 or 2, wherein the control device (100) is configured to: operate the electric supercharger (50) in a positive direction to generate a positive pressure above atmospheric pressure in the inlet manifold (70), open the EGR valve (45) for a first predetermined period with a first predetermined opening dimension and then close the EGR valve (45) after the first predetermined period has elapsed, and calculate a first pressure difference by comparing an internal pressure of the inlet manifold (70) measured during the first predetermined period with a first reference pressure, so that the control device (100) learns the opening dimension of the EGR valve (45). Device according to claim 3, wherein the control device (100) is configured to: open the EGR valve (45) for a second predetermined period with a second predetermined opening dimension and then close the EGR valve (45) after the second predetermined period has elapsed, wherein the second predetermined opening dimension differs from the first predetermined opening dimension, calculate a second pressure difference by comparing an internal pressure of the intake manifold (70) measured during the second predetermined period with a second reference pressure, calculate a ratio of the first pressure difference to the second pressure difference, and determine a compensation value for the opening of the EGR valve (45) based on the calculated ratio of the first pressure difference to the second pressure difference. Device according to any of the preceding claims, wherein the control device (100) is configured to determine that the EGR valve (45) is fixed when the measured internal pressure of the intake manifold (70) does not vary while the electric supercharger (50) is operated in a positive direction to generate a positive pressure above atmospheric pressure in the intake manifold (70), and an instruction to open the EGR valve to different opening dimensions is sent. Device according to any of the preceding claims, wherein the control device (100) is configured to determine that the EGR valve (45) is leaking when the measured internal pressure of the inlet manifold (70) deviates from a reference pressure by more than a predetermined pressure, while the electric supercharger (50) is operated in a positive direction to generate a positive pressure above atmospheric pressure in the inlet manifold (70), and an instruction to open the EGR valve to different opening dimensions is sent. Device according to any of the preceding claims, wherein the control device (100) is configured to: operate the electric supercharger (50) in reverse direction and generate a vacuum below atmospheric pressure in the inlet manifold (70), open the EGR valve (45) to a first predetermined extent for a first predetermined period, and close the EGR valve (45) after the first predetermined period has elapsed and compare an internal pressure of the inlet manifold (70) measured during the first predetermined period with a first reference pressure in order to determine the opening extent of the EGR valve (45). Device according to claim 7, wherein the control device (100) is configured to: open the EGR valve (45) for a second predetermined period with a second predetermined opening dimension, close the EGR valve (45) after the second predetermined period has elapsed, wherein the second predetermined opening dimension differs from the first predetermined opening dimension, calculate a first pressure difference by comparing the internal pressure of the intake manifold (70) measured during the first predetermined period with the first reference pressure, calculate a second pressure difference by comparing an internal pressure of the intake manifold (70) measured during the second predetermined period with a second reference pressure, and calculate a ratio of the first pressure difference to the second pressure difference.and to determine a compensation value for the opening of the EGR valve (45) based on the calculated ratio of the first pressure difference to the second pressure difference. Device according to any of the preceding claims, wherein the control device (100) is configured to determine that the EGR valve (45) is fixed when the measured internal pressure of the intake manifold (70), detected by the intake manifold pressure sensor (71), is not changed while the electric supercharger (50) is operated in reverse to generate a vacuum below atmospheric pressure in the intake manifold (70), and an instruction to open the EGR valve (45) with different opening dimensions is sent. Device according to any of the preceding claims, wherein the control device (100) is configured to determine that the EGR valve (45) is leaking when the measured internal pressure of the intake manifold (70), detected by the intake manifold pressure sensor (71), deviates from a reference pressure by more than a predetermined pressure, while the electric supercharger (50) is operated in reverse to generate a vacuum below atmospheric pressure in the intake manifold (70), and an instruction to open the EGR valve (45) to different opening dimensions is sent. Method for diagnosing an exhaust gas recirculation (EGR) valve provided in an EGR device, the method comprising: Determining (S10) by a control device whether an engine is switched off while the vehicle is in motion, by the control device; Operating (S30) an electric supercharger configured to change the internal pressure of an intake manifold, Measuring (S50) the internal pressure in the intake manifold, which varies on the basis of the opening width of the EGR valve, by an intake manifold pressure sensor, and Learning (S60) by the control device the opening dimension of the EGR valve on the basis of the measured internal pressure in the intake manifold. Method according to claim 11, further comprising: by the control device, operating the electric charger in a positive direction to generate a positive pressure above atmospheric pressure in the intake manifold, by the control device, opening the EGR valve for a first predetermined period with a first predetermined opening dimension, by the control device, closing the EGR valve after the first predetermined period has elapsed, and learning the opening dimension of the EGR valve by comparing the measured internal pressure of the intake manifold with a first reference pressure. The method according to claim 12, further comprising: by means of the control device, opening the EGR valve for a second predetermined period with a second predetermined opening dimension that differs from the first predetermined opening dimension; by means of the control device, closing the EGR valve after the second predetermined period has elapsed; by means of the control device, calculating a first pressure difference by comparing an internal pressure of the intake manifold measured during the first predetermined period with a first reference pressure and a second pressure difference by comparing an internal pressure of the intake manifold measured during the second predetermined period with a second reference pressure; and by means of the control device, determining a compensation value for the opening of the EGR valve as the ratio of the first pressure difference to the second pressure difference. A method according to any one of claims 11 to 13, further comprising: by the control device, operating the electric supercharger in reverse to generate a vacuum below atmospheric pressure in the intake manifold; by the control device, opening the EGR valve for a first predetermined period with a first predetermined opening dimension; by the control device, closing the EGR valve after the first predetermined period has elapsed; and learning the opening dimension of the EGR valve by the control device by comparing an internal pressure in the intake manifold measured during the first predetermined period with a first reference pressure. The method according to claim 14, further comprising: opening the EGR valve for a second predetermined period with a second predetermined opening dimension that differs from the first predetermined opening dimension, closing the EGR valve after the second predetermined period has elapsed, comparing the measured internal pressure of the intake manifold during the second predetermined period with a second reference pressure, and determining a compensation value for the opening of the EGR valve by the control device based on a first pressure difference between the first reference pressure and the internal pressure of the intake manifold, which is measured when the EGR valve is open with the first predetermined opening dimension, and a second pressure difference between the second reference pressure and the internal pressure of the intake manifold, which is measured.when the EGR valve is open to the second predetermined opening dimension. Method for diagnosing an exhaust gas recirculation (EGR) valve provided in an EGR device, the method comprising: by means of a control device, determining (S10) whether an engine is stopped and a diagnostic request condition and a learning readiness condition are met; by means of the control device, operating an electric supercharger configured to change the internal pressure of an intake manifold; measuring the internal pressure in the intake manifold, which varies based on the opening width of the EGR valve, using an intake manifold pressure sensor; by means of the control device, determining a fixation of the EGR valve based on the measured internal pressure in the intake manifold; by means of the control device, operating the electric supercharger in reverse to generate a vacuum below atmospheric pressure in the intake manifold; by means of the control device,Sending an instruction to open the EGR valve with different opening dimensions, by the control device; stopping the electric supercharger, by the control device; sending an instruction to close the EGR valve, and, by the control device, determining that the EGR valve is fixed when the measured internal pressure of the intake manifold does not change after the instruction to open the EGR valve has been sent to the different opening dimensions. The method according to claim 16, further comprising: by the control device, operating the electric supercharger in a positive direction to generate a positive pressure above atmospheric pressure in the intake manifold; by the control device, sending an instruction to open the EGR valve with different opening dimensions; by the control device, stopping the electric supercharger; by the control device, sending an instruction to close the EGR valve; and by the control device, determining that the EGR valve is fixed when the measured internal pressure of the intake manifold is not changed after the instruction to open the EGR valve has been sent to the various opening dimensions. Method for diagnosing an exhaust gas recirculation (EGR) valve provided in an EGR device, the method comprising: by means of a control device, determining (S10) whether an engine is stopped and a diagnostic request condition and a learn-ready condition are met; by means of the control device, operating an electric supercharger configured to change the internal pressure of an intake manifold; measuring the internal pressure in the intake manifold, which varies based on the opening width of the EGR valve, using an intake manifold pressure sensor; by means of the control device, determining a leakage of the EGR valve based on the measured internal pressure in the intake manifold; by means of the control device, operating the electric supercharger in reverse to generate a vacuum below atmospheric pressure in the intake manifold; by means of the control device,Sending an instruction to open the EGR valve with different opening dimensions, by the control device; stopping the electric supercharger, by the control device; sending an instruction to close the EGR valve; and, by the control device, determining that the EGR valve is leaking when the measured internal pressure of the intake manifold deviates from a reference pressure by more than a predetermined pressure. The method according to claim 18, further comprising: by the control device, operating the electric supercharger in a positive direction to generate a positive pressure above atmospheric pressure in the intake manifold; by the control device, sending an instruction to open the EGR valve with different opening dimensions; by the control device, stopping the electric supercharger; by the control device, sending an instruction to close the EGR valve; and by the control device, determining that the EGR valve is leaking when the measured internal pressure of the intake manifold deviates from a reference pressure by more than a predetermined pressure.

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