Abnormality diagnosing device for oil pressure sensor

Abstract

The present application aims to accurately diagnose a stuck abnormality of an oil pressure sensor. An engine is provided with an oil pump, a main oil passage, and an oil pressure sensor. An electronic control unit is provided with a processing circuit. The processing circuit executes a first determination process, a second determination process, and a diagnosis process. In the first determination process, when an operating state of the oil pump is a stable operating state in which a change speed of an oil pressure is low, it is determined whether a state in which a fluctuation amplitude of an output of the oil pressure sensor is small is continued. In the second determination process, when the operating state of the oil pump is a transient operating state in which the change speed of the oil pressure is high, it is determined whether a change amount of the output of the oil pressure sensor is reduced. In the diagnosis process, in a case where it is determined in the first determination process that the state in which the fluctuation amplitude is small is continued and it is determined in the second determination process that the change amount of the output is reduced, it is diagnosed that an abnormality has occurred in the oil pressure sensor.

Description

Technical Field

[0001] This invention relates to a diagnostic device for abnormalities in an oil pressure sensor. Background Technology

[0002] Engines in vehicles and other applications include an oil pump that supplies engine oil to lubrication systems and other components. Furthermore, in engines equipped with an oil pump, an oil pressure sensor is installed in the oil passage through which the engine oil discharged from the pump flows.

[0003] Oil pressure sensors sometimes experience a malfunction known as a "sticking abnormality," where the output remains almost unchanged. During engine operation, stable oil pressure pulsations occur in the oil passages. Furthermore, if this sticking abnormality occurs during engine operation, the change in oil pressure detected by the oil pressure sensor, specifically the change in the sensor's output, becomes smaller. Patent Document 1 describes a sticking abnormality occurring in an engine equipped with a hydraulic variable valve timing mechanism when the amplitude of the oil pressure sensor's output fluctuation remains small and the output indicates an oil pressure exceeding a predetermined low oil pressure threshold.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2023-22642 Summary of the Invention

[0005] Here, the amplitude of the output fluctuation of the oil pressure sensor may decrease not only due to the aforementioned jamming abnormality, but also sometimes due to deviations in the oil pressure pulsations that are stably generated in the oil passage, or electromagnetic noise generated in the circuit including the oil pressure sensor. Furthermore, in this case, even if the oil pressure sensor does not experience a jamming abnormality, it may be incorrectly diagnosed as having one.

[0006] The oil pressure sensor anomaly diagnostic device for solving the above-mentioned problem is an anomaly diagnostic device applied to an engine and used to diagnose whether the oil pressure sensor is abnormal. The engine includes: an oil pump; an oil passage for supplying engine oil discharged from the oil pump; and an oil pressure sensor for detecting the oil pressure in the oil passage. The oil pressure sensor anomaly diagnostic device is characterized by having a processing circuit that performs the following processing: a first determination process, in which, when the operating state of the oil pump is a stable operating state with a low rate of change of oil pressure, it is determined whether the state of small fluctuation amplitude of the output of the oil pressure sensor continues; a second determination process, in which, when the operating state of the oil pump is a transitional operating state with a high rate of change of oil pressure, it is determined whether the amount of change of the output of the oil pressure sensor decreases; and a diagnostic process, in which, if the first determination process determines that the state of small fluctuation amplitude continues and the second determination process determines that the amount of change of the output decreases, it is diagnosed that the oil pressure sensor is abnormal.

[0007] Invention Effects

[0008] According to the present invention, it is possible to diagnose the jamming abnormality of the oil pressure sensor with good accuracy. Attached Figure Description

[0009] Figure 1 This is a diagram schematically illustrating the configuration of one embodiment of an abnormality diagnosis device for an oil pressure sensor.

[0010] Figure 2 This is a flowchart representing the abnormal diagnosis process performed by the abnormality diagnosis device.

[0011] Figure 3 This is a flowchart illustrating the diagnostic process for this anomaly.

[0012] Figure 4 This is a timing diagram illustrating an example of how the abnormality diagnosis and handling process is executed. Detailed Implementation

[0013] The following is for reference. Figures 1-4 An embodiment of the abnormality diagnosis device for oil pressure sensors will be described in detail.

[0014] (The composition of the oil circulation system of engine 10)

[0015] First refer to Figure 1 The configuration of the oil circulation system of engine 10 will be described below. The oil circulation system of engine 10 includes an oil pump 11, an oil filter 14, an oil filter 15, and an oil pressure sensor 20. The oil pump 11 draws in engine oil from the oil pan 13 of engine 10 and discharges it. The oil filter 14 is a filter that removes larger impurities from the engine oil drawn in by the oil pump 11. The oil filter 15 is a filter that removes fine impurities from the engine oil discharged by the oil pump 11. The engine oil discharged by the oil pump 11 is sent to the main oil passage 16 after passing through the oil filter 15. Engine oil is supplied from the main oil passage 16 to each lubrication point 17 of engine 10. The oil pressure sensor 20 is a sensor that detects the oil pressure PO of the main oil passage 16. In this embodiment, the main oil passage 16 corresponds to the oil passage through which the engine oil discharged by the oil pump 11 flows.

[0016] Furthermore, in this engine 10, a mechanical pump that operates by receiving the rotation of the crankshaft 12, i.e., the rotation of the engine 10, is used as the oil pump 11. Also, in the engine 10, a variable displacement pump capable of controlling the amount of oil discharged is used as the oil pump 11.

[0017] (The structure of the control system of engine 10)

[0018] Next, refer to Figure 1The configuration of the control system for engine 10 will be described below. Engine 10 is controlled by electronic control unit 21. Electronic control unit 21 includes processing circuit 22. Processing circuit 22 includes: an arithmetic processing unit for executing various processes according to a program; and a storage unit for storing various programs and data. Various sensors are provided in engine 10 to detect state quantities representing the operating state of engine 10. The sensors include the aforementioned oil pressure sensor 20. In addition to the oil pressure PO detected by oil pressure sensor 20, the state quantities also include the rotational phase of crankshaft 12, which is the output shaft of engine 10, i.e., crankshaft angle. Detection signals of the state quantities detected by these sensors are input from engine 10 to electronic control unit 21. Electronic control unit 21 performs engine control based on the input detection signals. Furthermore, electronic control unit 21 calculates the rotational speed of crankshaft 12 (hereinafter referred to as engine speed NE) or engine load KL based on the state quantities of the input detection signals.

[0019] The engine control performed by the electronic control unit 21 includes control of the oil pump 11's output. The electronic control unit 21 calculates a target oil pressure TP, which is the control target value for oil pressure PO, based on factors such as engine speed NE or engine load KL. Furthermore, the electronic control unit 21 adjusts the output of engine oil from the oil pump 11 to ensure that the detected value RP of oil pressure PO from the oil pressure sensor 20 matches the target oil pressure TP. Thus, within a range sufficient to supply the amount of engine oil required to prevent seizing, power loss in the engine 10 related to the operation of the oil pump 11 is suppressed.

[0020] (Diagnosis of abnormality in oil pressure sensor 20)

[0021] The electronic control unit 21, as part of the engine control system, performs fault diagnosis on the oil pressure sensor 20. In this embodiment, the electronic control unit 21 corresponds to the fault diagnosis device for the oil pressure sensor 20. The electronic control unit 21 diagnoses in detail whether the oil pressure sensor 20 is stuck. A stuck fault is a malfunction of the oil pressure sensor 20 in which the output remains at a nearly constant value without change.

[0022] exist Figure 2 and Figure 3 The diagram shows the processing sequence for diagnosing whether the oil pressure sensor 20 is stuck. Furthermore, this processing is executed by the processing circuit 22 of the electronic control unit 21 according to a predetermined execution cycle. Hereinafter, the step numbers of each process are indicated by numbers beginning with "S".

[0023] Furthermore, in this embodiment, Figure 2The processing steps S101 to S105 are equivalent to the first determination process, which checks whether the small amplitude of the output fluctuation of the oil pressure sensor 20 continues when the oil pump 11 is in a stable operating state with a low rate of change in the oil pressure PO. Furthermore, Figure 3 The processing steps S201 to S206 are equivalent to a second determination process that checks whether the change in the output of the oil pressure sensor 20 decreases when the oil pump 11 is in a transitional operating state where the rate of change of the oil pressure PO is high. Furthermore, Figure 3 The processing in S207 is equivalent to a diagnostic process that diagnoses an abnormality in the oil pressure sensor 20. In the diagnostic process, if the first determination process determines that the state of small fluctuation amplitude continues and the second determination process determines that the change in the output of the oil pressure sensor 20 (specifically, the detection value RP) decreases, an abnormality in the oil pressure sensor 20 is diagnosed.

[0024] (First Decision Processing)

[0025] like Figure 2 As shown, in the first determination process, it is first determined whether the precondition is met (S101). The precondition satisfies all of the following requirements (i) to (iii). Requirement (i) is that the engine 10 has completed starting.

[0026] Requirement (ii) is that the engine 10 is in an idling state. Requirement (iii) is that the engine speed NE is above the predetermined diagnostic lower limit value N1.

[0027] Furthermore, if the precondition is not met (S101: "No"), this process temporarily ends. On the other hand, if the precondition is met (S101: "Yes"), it is determined whether the following condition (iv) is met (S102). Condition (iv) is that the absolute value of the difference between the moving average value of the output of the oil pressure sensor 20 and the instantaneous value of the output reaches a predetermined jamming judgment value J1 or below.

[0028] If, in the processing of S102, it is determined that the condition (iv) is met ("yes"), then, as a state with small fluctuation amplitude, it is determined whether the state in which the condition (iv) is met has lasted for more than the first predetermined time T1 (S103).

[0029] If the determination in S103 is affirmative ("yes"), since the output of the oil pressure sensor 20 continues to have a small fluctuation amplitude, the possibility of the oil pressure sensor 20 being stuck is high, and the temporary abnormality flag F1 is set to "on" (S104).

[0030] On the other hand, if the determination in S103 is negative ("no"), although the requirement (iv) is met, the duration of the met state is less than the first predetermined time T1, so the process in S104 is not executed, and the first determination process is temporarily terminated.

[0031] On the other hand, if the requirement (iv) is determined not to be met in the S102 process ("No"), since the fluctuation amplitude of the output of the oil pressure sensor 20 is large, the possibility of the jamming abnormality occurring is extremely low, and the temporary abnormality flag F1 is set to "Off" (S105). Thus, after setting the temporary abnormality flag F1, the first determination process is temporarily terminated.

[0032] (Second judgment and diagnosis)

[0033] exist Figure 3 In the series of processes shown, it is first determined whether the temporary abnormality flag F1 is set to "on" (S201). If the determination in S201 is negative ("no"), the following processes (S202 to S208) are not executed, and this process temporarily ends. On the other hand, if the determination in S201 is positive ("yes"), the process in S202 is executed. In this process, when the temporary abnormality flag F1 is set to "on", that is, when the first determination process temporarily determines (temporarily diagnoses) that the oil pressure sensor 20 has a stuck abnormality, the processing circuit 22 executes the following processes (S202 to S208).

[0034] In the processing of S202, it is determined whether the increase in the target oil pressure TP per unit time reaches or exceeds a predetermined judgment value J2. Specifically, in the processing of S202, it is determined whether the following condition (v) is met. Condition (v) is that the difference ΔTP (=TP[i]-TP[i-1]) between the latest set value TP[i] and the previous set value TP[i-1] of the target oil pressure TP set in the discharge control of oil pump 11 is or exceeds the predetermined judgment value J2. In addition, as the predetermined judgment value J2, in order to diagnose the occurrence of the jamming abnormality of oil pressure sensor 20, a value that can sufficiently ensure the increase in oil pressure PO is predetermined and stored in the storage device of processing circuit 22.

[0035] If, during the processing of S202, it is determined that requirement (v) is met ("Yes"), the detected value RP of the oil pressure PO based on the oil pressure sensor 20 is stored as "oil pressure PO1 before change" in the storage device of the processing circuit 22 (S203). On the other hand, if, during the processing of S202, it is determined that requirement (v) is not met ("No"), the processing of S203 is not executed.

[0036] Then, determine whether the following conditions (vi) and conditions (vii) are met simultaneously (S204).

[0037] The condition (vi) is that after the condition (v) is met, the engine speed NE increases by a predetermined judgment increase amount J3.

[0038] The requirement (vii) is a state in which the elapsed time after the requirement (vi) is met reaches a second predetermined time T2 or more.

[0039] Furthermore, as a determination of the rise amount J3 and the second predetermined time T2, in order to diagnose the occurrence of the jamming abnormality of the oil pressure sensor 20, a value that can sufficiently ensure the rise amount of the oil pressure PO is predetermined and stored in the storage device of the processing circuit 22. In this embodiment, the operating state of the oil pump 11 that satisfies conditions (v) and (vi) is equivalent to the transitional operating state of the oil pump 11. The transitional operating state occurs when the rise amount of the target oil pressure TP per unit time reaches or exceeds a predetermined determination value J2, and at the instant after the rise amount reaches or exceeds the predetermined determination value J2, the engine speed NE exceeds the predetermined determination rise amount J3 and rises.

[0040] In the process of S204, if the determination is negative ("No"), this process is temporarily terminated because the increase in engine speed NE is insufficient or the elapsed time after the increase in engine speed NE is short. In this case, the following processes (S205 to S208) are not performed.

[0041] On the other hand, if the determination in S204 is affirmative ("yes"), the oil pressure PO detected by the oil pressure sensor 20 is stored as "changed oil pressure PO2" in the storage device of the processing circuit 22 as the increase in engine speed NE or the aforementioned time elapsed sufficiently (S205).

[0042] Then, calculate the difference ΔPO (=PO2-PO1) between the changed oil pressure PO2 and the original oil pressure PO1, and determine whether the difference ΔPO is less than the predetermined judgment value J4 (S206).

[0043] Furthermore, if the determination in S206 is affirmative ("Yes"), the formal anomaly flag F2 is set to "On" (S207). In this case, the output of the oil pressure sensor 20 should change significantly due to the change in the operating state of the oil pump 11, but the change in the output is smaller. Therefore, the formal anomaly flag F2 is set to "On", and it is determined (formally diagnosed) that the oil pressure sensor 20 has a stuck anomaly.

[0044] On the other hand, if the determination in S206 is negative ("No"), the formal anomaly flag F2 is set to "Off" (S208). In this case, the output of the oil pressure sensor 20 should change significantly due to the change in the operating state of the oil pump 11, but the actual change in the output is large. Therefore, the probability of the aforementioned jamming anomaly occurring is low, and the formal anomaly flag F2 is set to "Off". In this case, although a jamming anomaly of the oil pressure sensor 20 is temporarily diagnosed in the first determination process, this diagnosis is not confirmed.

[0045] Thus, after setting the formal exception flag F2, this process temporarily ends.

[0046] (The role and effect of the implementation method)

[0047] Figure 4 An example of how an abnormal diagnosis process is executed, including a first determination process, a second determination process, and a diagnosis process, is shown.

[0048] like Figure 4 As shown, when the precondition is met at time t11, the processing circuit 22 executes the first determination process (see reference). Figure 2 In the first determination process, when the oil pump 11 is in a stable operating state, if the output amplitude of the oil pressure sensor 20 remains small for more than a predetermined time T1, it is temporarily diagnosed that the oil pressure sensor 20 has a stuck abnormality (time t12). At this time, the temporary abnormality flag F1 is set to "on".

[0049] When the oil pump 11 is in a stable operating state, the change in oil pressure PO accompanying the change in the operating state of the oil pump 11 is small. Therefore, the output (detected value RP) of the oil pressure sensor 20 reaches a value corresponding to the pulsation of oil pressure PO stably generated in the main oil passage 16. Therefore, in this stable operating state, the occurrence of jamming abnormality of the oil pressure sensor 20 can be diagnosed based on the amplitude (specifically, the amount of change) of the output of the oil pressure sensor 20. That is, it can be known that the output of the oil pressure sensor 20 varies with an amplitude corresponding to the pulsation of the aforementioned oil pressure PO, but this amplitude (specifically, the amount of change in output) is less than expected, or the output does not change. Therefore, it is known that the possibility of jamming abnormality of the oil pressure sensor 20 is high.

[0050] In this embodiment, during the abnormal diagnosis of the oil pressure sensor 20 in the stable operating state, a temporary determination of the occurrence of a jamming abnormality (temporary diagnosis) is made, but a definitive diagnosis of the occurrence of a jamming abnormality (formal diagnosis) is not made. This is for the following reasons: The amplitude of the output fluctuation of the oil pressure sensor 20 may decrease not only due to the occurrence of a jamming abnormality, but also sometimes due to deviations in the oil pressure pulsations that are stably generated in the main oil passage 16, or electromagnetic noise generated in the circuit including the oil pressure sensor 20 and the processing circuit 22. Furthermore, because the amplitude of the output fluctuation of the oil pressure sensor 20 is thus reduced, even if the oil pressure sensor 20 is not experiencing a jamming abnormality, it may be incorrectly diagnosed as having a jamming abnormality.

[0051] In this embodiment, under the condition of performing temporary diagnosis, the processing circuit 22 performs the second determination process and diagnosis process (see reference). Figure 3 In the second judgment process, when the oil pump 11 is in a transitional operating state (after time t13), the change in the output of the oil pressure sensor 20 decreases, thus determining (formal diagnosis) that the oil pressure sensor 20 has experienced a jamming abnormality (time t14). At this time, the formal abnormality flag F2 is set to "on". Additionally, as... Figure 4 As shown by the double-dotted line, when oil pump 11 is in transitional operation (after time t13), and the change in the output of oil pressure sensor 20 increases, no formal diagnosis is performed (time t14). In this case, the formal anomaly flag F2 remains "off".

[0052] During the transitional operating state of oil pump 11, the oil pressure PO changes significantly with the change in the operating state of oil pump 11. Therefore, in terms of detecting the change in the output of oil pressure sensor 20, the influence caused by electromagnetic noise or the deviation caused by the aforementioned oil pressure pulsation is small for the same amount of change. Therefore, it can be said that during the transitional operating state of oil pump 11, the influence of electromagnetic noise or the deviation of oil pressure pulsation is small for diagnosing jamming anomalies based on the change in the output of oil pressure sensor 20.

[0053] According to this embodiment, during the transitional operating state, the occurrence of a jamming abnormality in the oil pressure sensor 20 can be diagnosed based on the change in the output of the oil pressure sensor 20 (specifically, the difference ΔPO). That is, it is known that the output of the oil pressure sensor 20 should change significantly with the change in the operating state of the oil pump 11, but if the change in output is small or does not change, it is known that the possibility of a jamming abnormality in the oil pressure sensor 20 is high.

[0054] Thus, according to this embodiment, when the oil pump 11 is in a stable operating state, a temporary diagnosis of jamming abnormality in the oil pressure sensor 20 can be made. Furthermore, when the oil pump 11 is in a transitional operating state, i.e., when the influence caused by electromagnetic noise or oil pressure pulsation deviation is minimal, a jamming abnormality in the oil pressure sensor 20 can also be diagnosed, thereby confirming (formal diagnosis) the occurrence of the jamming abnormality. Therefore, the jamming abnormality of the oil pressure sensor 20 will not be erroneously diagnosed due to the influence of electromagnetic noise or oil pressure pulsation deviation.

[0055] The anomaly diagnosis device according to the above embodiment can achieve the following effects.

[0056] (1) In this embodiment, the oil pressure sensor 20 will not be incorrectly diagnosed as stuck due to the influence of electromagnetic noise or the deviation of oil pressure pulsation. Therefore, the stuck abnormality of the oil pressure sensor 20 can be diagnosed with good accuracy.

[0057] (2) In this embodiment, the oil pump 11 is a mechanical and variable capacity type. The stable operating state of the oil pump 11 is set to a state in which the rate of change of the engine speed NE per unit time and the rate of change of the target oil pressure TP are both low.

[0058] Therefore, in a stable operating state where the rate of change of oil pressure PO is low, the first determination process can be performed. Furthermore, the transitional operating state of the oil pump 11 is set to a state after the rate of change of the target oil pressure TP increases, and also a state where the rate of change of engine speed NE is high. Therefore, if the oil pressure sensor 20 does not experience any jamming abnormality, and if the increase in oil pressure PO is sufficiently ensured, the second determination process can be performed.

[0059] (3) In this embodiment, the stable operating state of the oil pump 11 is defined as the idling operating state of the engine 10. Therefore, the first determination process can be performed when the rate of change of oil pressure PO is extremely low. Furthermore, the transitional operating state is defined as when the increase in the target oil pressure TP per unit time reaches or exceeds a predetermined determination value J2, and at the instant that the increase reaches or exceeds the predetermined determination value J2, the engine speed NE exceeds a predetermined determination increase J3 and rises. Therefore, if the oil pressure sensor 20 does not experience any jamming abnormality, and the increase in oil pressure PO is sufficiently ensured, the second determination process can be performed.

[0060] (4) In this embodiment, the second determination process is performed under the condition that the state of small fluctuation amplitude is determined to continue in the first determination process. Specifically, it is performed under the condition that the temporary abnormality flag F1 is set to "on". According to this embodiment, when the engine 10 is in an idling state and the oil pump 11 is in a stable operating state, the first determination process can be performed to temporarily determine (temporarily diagnose) that the oil pressure sensor 20 has a stuck abnormality. Furthermore, at a subsequent moment, when the engine speed NE increases and the oil pump 11 is in a transitional operating state, the second determination process can be performed to determine (formally diagnose) the aforementioned temporary diagnosis. According to this embodiment, the diagnosis of the stuck abnormality of the oil pressure sensor 20 can be performed efficiently according to a series of processes from the operating state of the engine 10 to the acceleration operating state.

[0061] (Example of the change)

[0062] Furthermore, the above-described embodiments can be implemented with the following modifications. The above-described embodiments and the following modifications can be combined with each other to implement them without creating technical inconsistencies.

[0063] • Requirement (iii) can be omitted from the preconditions.

[0064] • The stable operating state can be set to any time other than when the engine 10 is idling. In short, the operating state of the oil pump 11, where the rate of change of oil pressure PO is slow, can be set to a stable operating state.

[0065] • The oil pump 11 is not limited to a variable capacity type; a pump of a type that cannot change the relationship between engine speed NE and the amount of engine oil discharged can also be used. In the same configuration, the stable operating state can be defined as when the rate of change of the rotational speed of the oil pump 11 or the rate of change of the engine speed NE is below a predetermined threshold. Furthermore, in the above configuration, the transitional operating state can be defined as when the rate of change of the rotational speed of the oil pump 11 or the rate of change of the engine speed NE is above a predetermined threshold.

[0066] • An electric pump can be used as the oil pump 11. In the same configuration, it is preferable to adopt condition (iii) that the drive power of the oil pump 11 is constant or higher. Furthermore, in the above configuration, when the oil pump 11 is in a stable operating state, it can be set such that the change in the target oil pressure TP per unit time is below a predetermined judgment value for a predetermined period of time or more. Moreover, in the above configuration, when the transitional operating state is set such that the change in the target oil pressure TP per unit time is greater than the predetermined judgment value and the period thereafter.

[0067] • Can be omitted Figure 3The processing of S201. In this case, the first determination process during stable operation and the second determination process during transitional operation can be executed at any time, regardless of whether it is before or after the execution period. Furthermore, if the first determination process determines that the state of small fluctuation amplitude continues and the second determination process determines that the change in the output of the oil pressure sensor 20 decreases, it is sufficient to diagnose that the oil pressure sensor 20 has a stuck abnormality.

[0068] Symbol Explanation

[0069] 10-Engine, 11-Oil pump, 12-Crankshaft, 13-Oil pan, 14-Oil filter, 15-Oil filter, 16-Main oil passage, 17-Lubrication unit, 20-Oil pressure sensor, 21-Electronic control unit, 22-Processing circuit.

Claims

1. An anomaly diagnostic device for an oil pressure sensor, applied to an engine and used to diagnose whether the oil pressure sensor is malfunctioning, the engine comprising: an oil pump; an oil passage for supplying engine oil discharged from the oil pump; and an oil pressure sensor for detecting the oil pressure in the oil passage, characterized in that... It has processing circuitry. The processing circuit performs the following processing: The first determination process involves determining whether the small amplitude of the output of the oil pressure sensor continues when the oil pump is in a stable operating state with a low rate of change in oil pressure. The second determination process involves determining whether the change in the output of the oil pressure sensor decreases when the oil pump is in a transitional operating state with a high rate of change in oil pressure; and In the diagnostic process, if the first determination process determines that the small amplitude of the fluctuation continues and the second determination process determines that the change in the output decreases, the oil pressure sensor is diagnosed as malfunctioning.

2. The abnormal diagnosis device for the oil pressure sensor according to claim 1, characterized in that, The oil pump is a mechanical pump that operates by receiving rotation from the output shaft of the engine, and is a variable displacement pump capable of controlling the amount of engine oil discharged. The stable operating state is a state in which both the rate of change of the rotational speed of the output shaft and the rate of change of the target oil pressure in the oil pump discharge control are low. The transitional operating state is a state after the rate of change of the target oil pressure becomes high, and it is also a state in which the rate of change of the rotational speed of the output shaft is high.

3. The abnormal diagnosis device for the oil pressure sensor according to claim 2, characterized in that, During the stable operating state, the engine is in an idling state. During the transitional operating state, after the increase in the target oil pressure per unit time reaches or exceeds a predetermined judgment value, and after the increase reaches or exceeds the predetermined judgment value, the rotational speed of the output shaft immediately exceeds the predetermined judgment increase and rises.

4. The abnormal diagnosis device for the oil pressure sensor according to any one of claims 1 to 3, characterized in that, The second determination process is performed under the condition that the state of small amplitude variation is determined to continue in the first determination process.

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