Diagnostic method, controller and motor vehicle

Abstract

This invention relates to a diagnostic method, a controller, and a motor vehicle, specifically a diagnostic method (100; 200; 200') in which a predicted value (103; 203) indicating the phase of the camshaft is predicted for a predetermined time point. Furthermore, an actual value (105; 205) indicating the phase of the camshaft is measured at the predetermined time point. Finally, a fault in the camshaft adjustment of the cylinder block valve for adjusting the cylinder block of an internal combustion engine is determined based on the predicted and actual values ​​(111; 219). Furthermore, this invention relates to a controller (500) and a motor vehicle (600) having the controller.

Description

Technical Field

[0001] This invention relates to a diagnostic method, and more particularly to a diagnostic method for identifying faults in camshaft adjustment, controllers, and motor vehicles. Background Technology

[0002] In unadjusted camshaft drive systems, the camshaft is driven by the crankshaft at half its rotational speed via a fixed connection (such as a toothed belt, chain, or gear). However, this fixed connection between the camshaft and crankshaft results in inefficient cylinder filling, meaning the fresh air share in the combustion chamber is suboptimal. Therefore, in gasoline engines, the fresh air share in the combustion chamber is detected by a fill detection function in the engine controller. This fresh air share in the combustion chamber is largely influenced by the opening and closing times of the intake and exhaust valves (cylinder valves). To achieve the most efficient cylinder filling across all engine speeds, camshaft adjustment is used to alter the intake and exhaust control times based on engine speed and throttle position. For camshaft adjustment, an adjustment unit is used, such as a hydraulic phase adjuster that operates using engine hydraulic pressure, also known as a Schwenk motor phase adjuster, and is typically placed at the end of the camshaft in the force transmission path.

[0003] In addition, methods and systems for controlling camshaft adjustment are known.

[0004] DE 10 2018 104 977 A1 describes a method for controlling a system for adjusting a variable camshaft. The method includes setting a camshaft adjuster using a camshaft duty cycle determined based on sampled camshaft positions, and setting the camshaft adjuster using an estimated camshaft position determined between camshaft duty cycles based on samples of the camshaft positions.

[0005] DE 102 21988 A1 describes a method for determining the position of a phasing system used for variable camshaft control of an engine with engine control (via which the intake and exhaust flow rates are regulated during combustion). The method includes the steps of generating models for estimating a calculated cam (shaft) position and a calculated rate of change of the cam position. The method also includes the steps of measuring the actual cam position and the actual rate of change of the cam position. According to the method, the calculated cam position is compared with the measured cam position, and the calculated rate of change of the cam position is blended or superimposed based on the comparison with the measured rate of change of the actual cam position. Engine control is adapted based on the blended rate of change of the cam position.

[0006] Here, a malfunction may occur during camshaft adjustment, which causes the opening and closing times of the sump valve to be set too slowly, or in the worst case, not at all.

[0007] For fault identification, WO 2004 / 092549 A1 describes an anomaly diagnostic device that diagnoses anomalies in an adjustable valve mechanism that alters the motion characteristics of valves in a combustion engine. For example, the diagnostic device estimates the phase angle (theoretical value) of the camshaft as a function of a target phase angle based on calculations from a physical model, and compares the theoretical value of the phase angle with the actual observed value of the phase angle to determine the “anomaly” of the adjustable valve mechanism.

[0008] Currently known methods and systems require a relatively long time to provide reliable fault diagnosis results. Summary of the Invention

[0009] The purpose of this invention is to provide a method, a controller, and a motor vehicle that achieves improved fault identification for camshaft adjustment.

[0010] This objective is achieved by a diagnostic method according to the invention, a controller according to the invention, and a motor vehicle having such a controller according to the invention.

[0011] Further advantageous embodiments of the invention will be derived from the technical solutions and the following description of preferred embodiments of the invention.

[0012] A first aspect of the present invention relates to a diagnostic method comprising the following steps:

[0013] Predict the phase of the camshaft for a predetermined time point;

[0014] The actual value of the phase of the camshaft is measured at a predetermined time point;

[0015] The fault in the camshaft adjustment of the cylinder block valve used to adjust the cylinder block of an internal combustion engine is determined based on predicted and actual values.

[0016] This diagnostic method can be applied to internal combustion engines comprising at least one cylinder, wherein cylinder filling can be set via the operation of cylinder block valves (e.g., intake valves and exhaust valves (scavenger valves)). The valves can be set via corresponding intake or exhaust camshafts. Here, the camshaft phase (camshaft phase) is set (adjusted), thereby allowing the control timing of the cylinder block valves to be set. The phase here can correspond to the camshaft position.

[0017] Basically, camshafts are set based on corresponding theoretical values, such as control or adjustment. Typically, the actual values ​​lag behind the theoretical values.

[0018] The predicted and actual values ​​indicate the camshaft phase, and therefore can indicate a parameter from which the valve movement of one or more cylinder block valves can be derived. In other words, this parameter indicates valve control or valve movement. For example, the predicted and actual values ​​can correspond to the camshaft phase.

[0019] If there is no fault in the camshaft adjustment used to set the cylinder block valve, the predicted value corresponds to the expected actual value at a predetermined time point (diagnostic time point). This means that the predicted value describes the phase under normal camshaft adjustment conditions.

[0020] Here, the predicted values ​​can be determined based on a model. For example, the model can be generated empirically, mathematically, physically, and / or statistically.

[0021] The forecast is made for a predetermined point in time, where the predetermined point in time is in the future. In other words, the forecast is predicted. Therefore, the forecast at the predicted point in time predicts the future camshaft phase.

[0022] The actual value is measured at the predetermined time point itself. Therefore, after the predicted value is predicted, a wait is made until the predetermined time point occurs, and then the actual value is measured. Thus, the actual phase of the camshaft at the predetermined time point can be derived from this actual value.

[0023] For example, the actual value can be determined via appropriate measuring equipment. For instance, the measuring equipment can be configured to detect camshaft phase. Therefore, sensors can be arranged at the camshaft sensor wheels of the intake and / or exhaust camshafts, which detect data from which the actual value can be determined.

[0024] Based on the predicted and actual values, faults in the camshaft adjustment can be identified. For example, the predicted values ​​are compared with the actual values.

[0025] "Camshaft adjustment" refers to moving the camshaft from the first phase (position) to the second phase (position), and vice versa.

[0026] A "malfunction" refers to the absence of normal camshaft adjustment function. For example, if the camshaft adjusts too slowly or is not in its phase, there is an abnormal function. The latter can also be referred to as a suspended camshaft.

[0027] By using predicted and actual values ​​for fault analysis, the speed of camshaft adjustment can be monitored. Furthermore, faults in camshaft adjustment can be quickly identified, for example, compared to monitoring the control loop used for setting components. Therefore, this diagnostic method achieves relatively rapid fault identification.

[0028] The predicted values ​​can be provided for use in calculating the air mass for the fuel occupancy test.

[0029] In another implementation, the predetermined time point for making the prediction can be in the future.

[0030] In other embodiments, the camshaft may include an intake camshaft or an exhaust camshaft. Therefore, the camshaft may include either an intake camshaft for setting the intake valves of the cylinder block and / or an exhaust camshaft for setting the exhaust valves of the cylinder block. That is, the prediction of the predicted value and the determination of the actual value can be performed with respect to the phase of the intake camshaft and / or the exhaust camshaft.

[0031] In another implementation, the cylinder block valve can be an intake valve or an exhaust valve.

[0032] In other embodiments, the predetermined time points can be the opening or closing time points of the cylinder block valves. In some examples, the phase of the intake camshaft can be predicted at the "intake valve open" time point and the "intake valve close" time point, and the phase of the exhaust camshaft can be predicted at the "exhaust valve close" time point. At these time points, the predicted values ​​for the camshaft phase can be determined particularly simply and accurately.

[0033] In another implementation, the diagnostic method can be performed within a predetermined diagnostic time period. This predetermined diagnostic time period can be selected such that it corresponds to the operating period of the internal combustion engine during which camshaft adjustments are made. Thus, the method can be implemented in a resource-efficient manner in terms of computational performance.

[0034] In other implementations, faults can be identified based on the difference between predicted and actual values. The "difference" refers to the predicted value minus the actual value, or vice versa. By analyzing the difference between predicted and actual values, the camshaft adjustment speed can be monitored. Therefore, camshaft adjustments that are too slow can be identified. Additionally or alternatively, suspended camshaft adjustments, where the camshaft is suspended / locked, can also be identified.

[0035] In another implementation, a fault can be determined based on the difference between the predicted and actual values ​​being equal to or greater than a predetermined limit. Therefore, if the difference is greater than the predetermined limit, a fault can be identified. Alternatively, the fault can also be derived from a difference greater than a predetermined limit.

[0036] For example, predetermined limit values ​​can be selected such that they indicate slow or suspended camshaft adjustments. Comparing the difference to the predetermined limit value can be easily done in diagnostic software. This allows for particularly simple identification of faults in camshaft adjustments.

[0037] In other implementations, the prediction of the predicted value and the determination of the actual value can be performed iteratively (e.g., over a predetermined diagnostic time period) for multiple predetermined time points. Furthermore, the diagnostic method may also include:

[0038] If the difference between the predicted and actual values ​​is equal to or greater than a predetermined limit, a fault criterion is detected in each iteration step; and

[0039] If the number of fault criteria is equal to or greater than the predetermined number, then a fault is determined.

[0040] Here, the predetermined diagnostic time period includes multiple predetermined time points. In other words, multiple predetermined time points are located within the predetermined diagnostic time period.

[0041] The fault criteria here can be understood as fault suspicion. A fault is determined only when the number of fault criteria within the diagnostic time period is equal to or greater than a predetermined number (the number of fault criteria). This achieves fault debouncing (sometimes also called fault screening), which makes the diagnostic method and thus fault identification design more robust.

[0042] In another implementation, the predetermined quantity can be set for a predetermined time interval (entprellzeit). This means the predetermined quantity is limited to a predetermined time interval. For example, the predetermined time interval can be from 0.5 seconds to 1 second. In some examples, the predetermined time interval can be 1 second. For example, if a fault criterion is first determined in the iterative loop, the predetermined time interval can be started or initiated.

[0043] Therefore, if the number of fault criteria exceeds a predetermined number within a predetermined time interval, a fault can be identified. This allows for more robust design of diagnostic methods and fault identification mechanisms.

[0044] In other implementations, the predetermined limit values ​​can depend on the operating strategy of the internal combustion engine. For example, the operating strategy may include meeting dynamic load requirements (acceleration, braking, etc.). Here, different predetermined limit values ​​can be set for different operating strategies. Therefore, fault identification can be performed more accurately.

[0045] In another implementation, the predetermined limit value may depend on the type of camshaft adjustment failure. The failure type refers to the various failures that may occur during camshaft adjustment.

[0046] Therefore, in some implementations, the fault types may include slow camshaft adjustment and suspended (locked) camshaft adjustment.

[0047] In some implementations, two predetermined limit values ​​can be set, where the first predetermined limit value indicates excessively slow camshaft adjustment, and the second predetermined limit value indicates excessively slow camshaft adjustment. This allows for more refined fault identification.

[0048] A second aspect of the invention relates to a controller configured to implement one of the diagnostic methods described above.

[0049] A third aspect of the invention relates to a motor vehicle having the controller. Here, the motor vehicle is also constructed and configured to implement one of the diagnostic methods described above. For this purpose, the motor vehicle includes an internal combustion engine. For example, the motor vehicle may include a powertrain driven purely by an internal combustion engine or a hybrid powertrain. Attached Figure Description

[0050] Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings. Wherein:

[0051] Figure 1 The diagnostic method according to the first embodiment is shown;

[0052] Figure 2 The diagnostic method according to the second embodiment is shown;

[0053] Figure 3 The diagnostic method according to the third embodiment is shown;

[0054] Figure 4 The graphs show the theoretical, predicted, and actual values ​​of camshaft phase, as well as fault criteria; and

[0055] Figure 5 The illustration shows a motor vehicle with a controller. Detailed Implementation

[0056] Figure 1 A diagnostic method 100 for determining a fault in camshaft adjustment, according to a first embodiment, is illustrated. Here, boxes S and E represent the start and end of the diagnostic method 100. For example, the diagnostic method 100 can begin if a diagnostic time period begins. For example, the diagnostic time period can begin if a predetermined event occurs, such as if a driver expectation (e.g., vehicle acceleration) is detected and a corresponding control signal is transmitted via controller 500 (shown later) to the (shown later) internal combustion engine of vehicle 600.

[0057] In box 101, theoretical values ​​are determined for a predetermined time point, wherein the theoretical values ​​indicate the camshaft positions of the intake camshaft and / or exhaust camshaft used to operate the internal combustion engine, for example, to achieve the load requirements in the driving mode of the motor vehicle 600.

[0058] The predetermined time point could be, for example, the opening or closing time of the intake valve of the internal combustion engine block of the motor vehicle 600, or the closing time of the exhaust valve. Based on the predetermined time point, the theoretical value is therefore measured for the intake camshaft or the exhaust camshaft.

[0059] In box 103, predicted values ​​are determined based on theoretical values ​​for a predetermined point in time (in the future), wherein the predicted values ​​indicate the camshaft positions of the intake camshaft and / or exhaust camshaft.

[0060] Predicted values ​​can be determined based on a model. For example, theoretical values ​​can be input into a model, which outputs predicted values.

[0061] In box 105, an actual value is determined at a predetermined time point, wherein the actual value indicates the actual camshaft position of the intake camshaft and / or exhaust camshaft. That is, after determining the predicted value, a wait is made until the predetermined time point occurs so that the actual camshaft position can then be determined at the predetermined time point. For example, the actual value can be determined based on data from sensors located at the camshaft sensor wheels of the intake camshaft and / or exhaust camshaft.

[0062] In box 107, the predicted value for a predetermined time point is compared with the actual value. Here, the difference between the predicted and actual values ​​is determined. Figure 4 The deviation (difference) shown is 407.

[0063] In box 109, it is checked whether the deviation 407 is equal to or greater than a predetermined limit value. Alternatively, it can be checked whether the deviation 407 is greater than another predetermined limit value 407. The predetermined limit value can indicate a first fault. The other predetermined limit value can indicate a second fault. Here, the first fault corresponds to the suspended camshaft adjustment, and the second fault corresponds to slow camshaft adjustment.

[0064] If the check in box 109 shows that the deviation 407 is equal to or greater than the predetermined limit value, the method proceeds to box 111.

[0065] In block 111, a fault is then determined in the camshaft adjustment. That is, the intake camshaft or exhaust camshaft (depending on which predetermined time point is considered) is adjusted too slowly or not adjusted at all (i.e., locked / hung). In block 111, the fault entry can additionally be stored in the controller 500, for example, in its memory 504.

[0066] If the check in box 109 shows that the deviation 407 is less than the predetermined limit value, then it is determined that there is no fault and the camshaft adjustment is therefore performed normally. Then, method 100 proceeds to box E and thus terminates.

[0067] In a modification of diagnostic method 100, the diagnostic method can also be implemented iteratively. Therefore, if the check in box 109 shows that the deviation 407 is less than a predetermined limit value, diagnostic method 100 can jump back to box 101 (see dashed line). Iteration can be performed according to a time grid, i.e., iterations are performed at predetermined (and, if necessary, regular or even uniform) time intervals.

[0068] In another modification, diagnostic method 100 can be repeatedly implemented. Therefore, diagnostic method 100 can be implemented, for example, according to a time grid each time.

[0069] Figure 2 A diagnostic method 200 for determining a fault in camshaft adjustment, according to a first embodiment, is illustrated. Here, boxes S and E represent the start and end of the diagnostic method 200. For example, the diagnostic method 200 can begin if a diagnostic time period begins.

[0070] Boxes 201, 203, 205, and 207 of diagnostic method 200 correspond to Figure 1 Diagnostic methods 100 are defined in boxes 101, 103, 105, or 107. To avoid repetition, the above description therefore applies.

[0071] In box 209, the deviation 407 between the predicted and actual values ​​is checked to see if it is equal to or greater than a predetermined limit value. Here, the predetermined limit value indicates the first fault in the camshaft adjustment. For example, the first fault may include a suspended (locked) camshaft adjustment.

[0072] If the check in block 209 finds that deviation 407 is equal to or greater than a predetermined limit value, the method proceeds to block 213. In block 213, a first fault criterion k1 is detected, and the corresponding entry is stored, for example, in the memory 504 of the controller 500.

[0073] If the check in box 209 shows that the deviation 407 is less than the predetermined limit value, then the diagnostic method proceeds to box 211.

[0074] In box 211, check whether the deviation 407 between the predicted and actual values ​​is equal to or greater than (in [the box]). Figure 4 (As shown in the diagram) another predetermined limit value (409). This other predetermined limit value 409 is less than the predetermined limit value. This other predetermined limit value 409 indicates a second fault in the camshaft adjustment. For example, the second fault could include camshaft adjustment that is too slow.

[0075] If the check in box 211 finds that the deviation 407 is less than another predetermined limit value 409, then diagnostic method 200 jumps back to box 201. For example, the re-execution of box 201 can be performed in the next calculation step of the time grid. That is, the re-execution of box 201 is performed at predetermined (and, if necessary, regular or even uniform) time intervals.

[0076] If the check in block 211 finds that deviation 407 is equal to or greater than another predetermined limit value, the method proceeds to block 213. In block 213, a second fault criterion k2 is detected, and the corresponding entry is stored, for example, in the memory 504 of the controller 500.

[0077] In box 213, the first fault criterion k1 and / or the second fault criterion k2 are therefore detected. If the first fault criterion k1 and / or the second fault criterion k2 are detected for the first time in box 213 (during the diagnostic time period), fault debouncing begins.

[0078] Following block 213, the method proceeds to block 215. In block 215, it is checked whether the time elapsed since the first detection of the first fault criterion k1 and / or the second fault criterion k2 is equal to or greater than a predetermined time interval (debouncing time). The time points of the first detection of the first fault criterion k1 and / or the second fault criterion k2 can be stored in memory 504. Therefore, two such detection time points can also be stored, one for the first detection of the first fault criterion k1 and the other for the first detection of the second fault criterion k1.

[0079] If the check in box 215 determines that the elapsed time is less than the debouncing time, then diagnostic method 200 jumps back to box 201. For example, the re-execution of box 201 can be performed in the next calculation step of the time grid. In some examples, in box 215, if the first fault criterion k1 was detected before the second fault criterion k2, the check of the elapsed time is performed with reference to the initial detection time of the first fault criterion k1. In other examples, in box 215, if the second fault criterion k1 was detected before the first fault criterion k1, the check of the elapsed time is performed with reference to the initial detection time of the second fault criterion k2.

[0080] If the check in box 215 shows that the elapsed time is equal to or greater than the dejitter time, then the diagnostic method proceeds to box 217.

[0081] In block 217, it is checked whether the number of detected first fault criteria k1 or the number of detected second fault criteria k2 is equal to or greater than a predetermined number. The number of detected first fault criteria k1 and / or second fault criteria k2 can be stored in memory 504.

[0082] If the check in block 217 determines that the number of first fault criteria k1 or second fault criteria k2 is equal to or greater than a predetermined number, then the method proceeds to block 219. In block 219, a fault is determined to exist in the camshaft adjustment. Therefore, the fault entry can be stored in the memory 504 of the controller 500.

[0083] If the check in block 217 determines that the number of first fault criteria k1 or second fault criteria k2 is less than a predetermined number, the method proceeds to block 221. In block 221, it is determined that there is no fault in the camshaft adjustment. Therefore, no fault entries are stored in the memory 504 of the controller 500.

[0084] Based on whether the number of first fault criteria k1 or second fault criteria k2 exceeds a predetermined number, the corresponding fault entries are stored. For example, the first fault criterion k1 indicates a first fault including camshaft adjustment of the suspension, and the second fault criterion k2 indicates a second fault including camshaft adjustment that is too slow.

[0085] After box 219, terminate diagnostic method 200 in box E.

[0086] In diagnostic method 200, fault de-jittering is performed by comparing predicted values ​​with actual values ​​at various predetermined time points within the de-jittering time and comparing the number of fault criteria k1, k2 with the predetermined number of fault criteria. Therefore, fault identification through diagnostic method 200 can be designed to be more robust.

[0087] Diagnostic method 200 can also be modified so that only one of boxes 209 and 211 is set. Therefore, diagnostic method 200 can be designed to identify only one type of fault, namely, camshaft adjustment that is too slow or camshaft adjustment that is locked.

[0088] In other words, if only box 209 is set in the modified scheme, and the deviation 407 is found to be less than the predetermined limit 409, then diagnostic method 200 returns to box 201 instead of box 211. If the deviation 407 is found to be equal to or greater than the predetermined limit, then diagnostic method 200 proceeds to box 213.

[0089] If only box 211 is set in the modified scheme, then the above description of box 211 applies.

[0090] In another modification, the order of checking the predetermined limit value and another predetermined limit value can also be interchanged. This means that in box 209, the deviation 407 is checked to see if it is equal to or greater than another predetermined limit value 409. Therefore, in box 211, the deviation 407 is checked to see if it is equal to or greater than the predetermined limit value.

[0091] Figure 3 A diagnostic method 200' according to a third embodiment is shown. The diagnostic method 200' according to the third embodiment differs from the diagnostic method 200 according to the second embodiment in boxes 211' and 215'. If a diagnostic time period begins, the diagnostic method 200' is implemented for the first time. During the diagnostic time period, the diagnostic method 200' is implemented multiple times at predetermined time intervals. The predetermined time intervals can be, for example, regular or even uniform.

[0092] In box 211', check whether the deviation 407 between the predicted and actual values ​​is equal to or greater than (in... Figure 4 (as shown in the diagram) another predetermined limit value (409). If the check in box 211 shows that the deviation 407 is less than the other predetermined limit value 409, then the diagnostic method 200' is terminated.

[0093] If the check in box 211' finds that the deviation 407 is equal to or greater than another predetermined limit value, then the method proceeds to box 213.

[0094] In block 215', it is checked whether the time elapsed since the first detection of the first fault criterion k1 and / or the second fault criterion k2 is equal to or greater than the debouncing time. The time point of the first detection of the first fault criterion k1 and / or the second fault criterion k2 can be stored in memory 504. In some examples, in block 215', if the first fault criterion k1 was detected before the second fault criterion k2, the check of the elapsed time is performed with reference to the time point of the first detection of the first fault criterion k1. In other examples, in block 215', if the second fault criterion k1 was detected before the first fault criterion k1, the check of the elapsed time is performed with reference to the time point of the first detection of the second fault criterion k2.

[0095] If the check in box 215' shows that the elapsed time is less than the dejitter time, then diagnostic method 200' is terminated. If the check in box 215' shows that the elapsed time is equal to or greater than the dejitter time, then the diagnostic method proceeds to box 217.

[0096] Fault debouncing is performed by executing diagnostic method 200' multiple times. This is done by comparing predicted and actual values ​​at various predetermined time points within the debouncing time and comparing the number of fault criteria k1, k2 with the predetermined number of fault criteria. Therefore, the fault identification design via diagnostic method 200' can be made more robust.

[0097] The modifications described in the diagnostic method 200 according to the second embodiment can also be applied to the diagnostic method 200' according to the third embodiment.

[0098] exist Figure 4 Figure 400 illustrates a typical driving scenario with load variations, specifically a brief load requirement for acceleration of the vehicle 600. Here, the load requirement begins at time t0. To meet the load requirement, the cylinder filling of the internal combustion engine of the vehicle 600 is set via corresponding valve control. Valve control is performed via a camshaft assembly, which includes an intake camshaft for controlling the intake valves of the cylinder and an exhaust camshaft for controlling the exhaust valves of the cylinder. Specifically, the valve opening time is set here via the camshaft assembly. The valve opening time is controlled by the phase of the corresponding camshaft.

[0099] Chart 400 is divided into three regions, which represent the camshaft position u at time t, the deviation ∆ between the predicted and actual values, and the existence of the fault criterion k.

[0100] Therefore, Figure 400 shows the theoretical value curve 401, the predicted value curve 403, and the actual value curve 405 for the camshaft phase. Furthermore, the deviation 407 between the predicted value curve 403 and the actual value curve 405 is shown. Finally, a fault criterion curve 411 is shown, indicating a fault in the camshaft adjustment. For example, Figure 400 can be generated by the execution of diagnostic method 200 or by multiple executions of diagnostic method 200', where box 209 is not set. Figure 4 The curves in the diagram are shown qualitatively and schematically.

[0101] Theoretical value curve 401 is a preset curve for the camshaft phase of the intake camshaft and / or exhaust camshaft used to achieve load requirements, controlled / adjusted.

[0102] Predicted value curve 403 here represents the predicted camshaft phase at a predetermined time point. Predicted value curve 403 here represents the expected actual curve, indicating that the camshaft adjustment is functioning correctly and there is no malfunction.

[0103] Actual curve 405 is the detected and therefore actual curve of the camshaft phase.

[0104] from Figure 4 It can be identified that the actual value deviates from the predicted value, or in other words, the actual value curve 405 deviates from the predicted value curve 403. This deviation (difference) or this deviation curve (difference curve) 407 indicates a fault in the camshaft adjustment. In particular, if the difference between the predicted value and the actual value exceeds another predetermined limit value 409, as is the case from time point t1, then the deviation indicates a fault. The difference curve 407 here depicts the magnitude of the difference between the predicted value and the actual value.

[0105] exist Figure 4The curve 411 for the (second) fault criterion k2 is shown. Here, if the difference 407 exceeds another predetermined limit value 409, the value of the second fault criterion k2 is set to "1".

[0106] After time point t2, the difference 407 between the predicted value and the actual value is again less than another predetermined limit value 409. Therefore, the second fault criterion k2 no longer exists, and the value of the fault criterion falls to "0" again.

[0107] Figure 5 A motor vehicle 600 with a controller 500 is schematically shown.

[0108] The motor vehicle 600 includes at least one drive unit driven by an internal combustion engine. A controller 500 is arranged in the motor vehicle 600.

[0109] The controller 500 can be configured as an engine controller and is set to implement the diagnostic methods 100 and 200 described above. The controller 500 includes a processor 502, a memory (electronic memory medium) 504, and an interface 508. Furthermore, software (computer program) 506, designed to implement the diagnostic methods 100 and 200, is also stored in the memory 504. The processor 502 is designed to implement the program instructions of the software 506. The interface 508 is further designed to receive and transmit data. For example, it can be an interface to the vehicle's CAN bus, via which the controller 500 receives signals and sends control commands.

[0110] List of reference numerals

[0111] 100 Diagnostic Methods

[0112] 200 Diagnostic Methods

[0113] 200' Diagnostic Methods

[0114] 400 Charts for theoretical value curves, predicted value curves, actual value curves, and fault criterion curves.

[0115] 402 CAN bus

[0116] 500 controller

[0117] 502 processor

[0118] 504 memory

[0119] 506 software

[0120] 508 interface

[0121] 600 Motor vehicles.

Claims

1. A diagnostic method, comprising: The theoretical values ​​used to achieve the load requirements are determined at predetermined time points, where, The theoretical value indicates the camshaft position used to operate the internal combustion engine. Predicted values ​​that indicate the phase of the camshaft based on theoretical values ​​for a predetermined point in the future; The actual value indicating the phase of the camshaft is determined at the predetermined time point; A fault in the camshaft adjustment of the cylinder block valve for adjusting the cylinder block of an internal combustion engine is determined based on the predicted value and the actual value, wherein the fault is determined based on the difference between the predicted value and the actual value being equal to or greater than a predetermined limit value.

2. The diagnostic method according to claim 1, wherein, The camshaft includes an intake camshaft or an exhaust camshaft.

3. The diagnostic method according to claim 1, wherein, The cylinder valve is either an intake valve or an exhaust valve.

4. The diagnostic method according to claim 1, wherein, The predetermined time point is the opening or closing time point of the cylinder valve.

5. The diagnostic method according to claim 1, wherein, The diagnostic method is performed during a predetermined diagnostic time period.

6. The diagnostic method according to claim 1, wherein, The prediction of the predicted value and the determination of the actual value are iteratively performed at multiple predetermined time points, and the diagnostic method further includes: If the difference between the predicted value and the actual value is equal to or greater than the predetermined limit value, a fault criterion is detected in each iteration step; and If the number of fault criteria is equal to or greater than the predetermined number, then a fault is determined.

7. The diagnostic method according to claim 6, wherein, The predetermined quantity is set for a predetermined time interval.

8. The diagnostic method according to any one of claims 1 to 7, wherein, The predetermined limit value depends on the operating strategy of the internal combustion engine.

9. The diagnostic method according to any one of claims 1 to 7, wherein, The predetermined limit value depends on the type of malfunction in the camshaft adjustment.

10. The diagnostic method according to claim 9, wherein, The fault types include slow camshaft adjustment and suspended camshaft adjustment.

11. A controller configured to implement the diagnostic method according to any one of claims 1-10.

12. A motor vehicle having a controller according to claim 11.

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