Abnormality determination device for internal combustion engine
By delaying and smoothing the accelerator pedal input and adjusting the corresponding torque deviation threshold for the response delay, the problem of misjudging the internal combustion engine as an abnormal state during deceleration is solved, thus improving the accuracy of abnormality detection.
Patent Information
- Application Number
- CN202510610636.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-05-15
- Filing Date
- 2025-05-13
- Publication Date
- 2025-11-18
AI Technical Summary
Existing technology is prone to misjudging abnormal conditions when the internal combustion engine is decelerating because the response delay caused by changes in the accelerator pedal operation leads to excess torque exceeding the threshold.
By delaying and smoothing the accelerator pedal input and adjusting the torque deviation threshold accordingly, the possibility of misjudgment is reduced.
It effectively reduces the possibility of internal combustion engines being misjudged as abnormal during deceleration, and improves the accuracy of abnormality determination.
Smart Images
Figure CN120968929A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to an abnormality determination device of an internal combustion engine for determining whether the internal combustion engine is in an abnormal state in which excessive torque is generated. BACKGROUND
[0002] The conventional device controls the internal combustion engine in such a manner that the internal combustion engine generates torque corresponding to a required torque. The conventional device estimates torque actually generated by the internal combustion engine, and determines that the internal combustion engine is in the above-described abnormal state in a case where a state in which excess torque obtained by subtracting the required torque from the estimated torque is equal to or greater than a torque deviation threshold value continues for a continuation time threshold value or more. The conventional device determines the torque deviation threshold value and the continuation time threshold value in accordance with an accelerator pedal operation amount having a correlation with a vehicle speed (for example, refer to Patent Literature 1).
[0003] [Patent Literature]
[0004] [Patent Literature]
[0005] [Patent Literature 1] Japanese Patent Application Publication No. 2017-14972 SUMMARY
[0006] In a case where the accelerator pedal operation amount is changed from a certain value to 0 (i.e., immediately after the deceleration state occurs), the required torque, the torque deviation threshold value, and the continuation time threshold value are immediately reduced in accordance with the reduction in the accelerator pedal operation amount, respectively. On the other hand, in a case where the accelerator pedal operation amount is changed from a certain value to 0, although the opening degree of the throttle valve is sharply reduced, the intake air amount does not immediately reduce, but is reduced in a manner having a response delay. Therefore, the torque generated by the internal combustion engine is also reduced in a delayed manner with respect to the change in the accelerator pedal operation amount. That is, the internal combustion engine has a response delay with respect to the change in the required torque. Therefore, when the deceleration state occurs, the torque actually generated by the internal combustion engine becomes greater than the required torque, so the state in which the excess torque is equal to or greater than the torque deviation threshold value easily continues. As a result, there is a possibility that the internal combustion engine is erroneously determined to be abnormal. The present application is achieved in order to cope with the above-described problem.
[0007] In one embodiment of the abnormality determination device of the internal combustion engine of the present application, there are provided: a control section (21, 22, 23) that controls an internal combustion engine (10) in such a manner that the internal combustion engine generates a torque equivalent to a required torque (Treq) determined on the basis of an accelerator pedal operation amount (AP); and an abnormality determination section (27) that estimates a torque actually generated by the internal combustion engine as an internal combustion engine torque (Tact) and determines that the internal combustion engine is in an abnormal state in the case where an excess torque (Qex) that is an excess amount of the internal combustion engine torque with respect to the required torque is larger than a torque deviation threshold value (Qth), wherein the abnormality determination device of the internal combustion engine is provided with a threshold value operation section (26) configured to determine whether or not the internal combustion engine is in a deceleration state (B1 to B4) on the basis of a difference (dT) between the required torque (Treq) and a smoothed processed required torque (Trb) that is a result of performing a delay smoothing process on the required torque, the delay smoothing process being equivalent to a response delay of the internal combustion engine with respect to a change in the required torque, calculate a reference value (Qth0) of the torque deviation threshold value on the basis of the accelerator pedal operation amount, determine the reference value (Qth0) as the torque deviation threshold value (Qth) in the case where it is determined that the internal combustion engine is not in the deceleration state, and determine a smoothed processed torque deviation threshold value (Qblr) that is a result of performing a delay smoothing process on the reference value (Qth0) equivalent to the response delay of the internal combustion engine as the torque deviation threshold value (Qth) in the case where it is determined that the internal combustion engine is in the deceleration state.
[0008] Thus, in the deceleration state in which the accelerator pedal operation amount is reduced, the torque deviation threshold value is changed in a manner corresponding to the response delay of the internal combustion engine, and therefore it is difficult for the excess torque (Qex) to become larger than the torque deviation threshold value (Qth). Thus, it is possible to reduce the possibility of erroneously determining that the internal combustion engine is in an abnormal state when the deceleration state occurs. BRIEF DESCRIPTION OF DRAWINGS
[0009] Figure 1 is a schematic configuration diagram of an abnormality determination device of an internal combustion engine according to an embodiment of the present application.
[0010] Figure 2 is a functional block diagram of the abnormality determination threshold value operation section shown in Figure 1
[0011] Figure 3 is a routine executed by a CPU of the engine ECU shown in Figure 1 DETAILED DESCRIPTION
[0012] The abnormality determination device of the internal combustion engine of the embodiment of the present application (hereinafter referred to as "the present device") is assembled in an engine control unit (ECU) that controls an internal combustion engine mounted in a vehicle such as an automobile. Figure 1 A fuel injection / spark ignition type / gasoline engine, i.e., a multi-cylinder internal combustion engine 10 (hereinafter, sometimes simply referred to as "internal combustion engine 10") shown is controlled by an engine ECU 20. The engine ECU 20 is an electronic control device provided with a microcomputer including a CPU, a ROM, a RAM, a nonvolatile memory, and the like. The ROM stores constants, lookup tables, programs, and the like. The engine ECU 20 controls "fuel injection valves 11, an ignition device 12, and a throttle motor 13" that are actuators of the internal combustion engine 10.
[0013] The engine ECU 20 acquires output values of the sensors listed below.
[0014] • An accelerator pedal operation amount sensor 31 that detects an accelerator pedal operation amount AP.
[0015] • A vehicle speed sensor 32 that detects a speed (vehicle speed) SPD of a vehicle on which the internal combustion engine 10 is mounted.
[0016] • An engine speed sensor 33 that detects a rotational speed NE of the internal combustion engine 10.
[0017] • An air flow meter 34 that detects an intake air amount Ga of the internal combustion engine 10.
[0018] • An air-fuel ratio sensor 35 that detects an air-fuel ratio AF of exhaust gas of the internal combustion engine 10.
[0019] The engine ECU 20 controls a warning device 30 provided with a warning buzzer and a warning lamp. The engine ECU 20 is provided with various function execution sections (21-28) described below that are realized by the CPU executing a program.
[0020] A required torque calculation section 21 calculates a required torque Treq by applying the detected accelerator pedal operation amount AP and the detected vehicle speed SPD to a predetermined lookup table MapTreq (AP, SPD). According to the table MapTreq (AP, SPD), the greater the accelerator pedal operation amount AP, the greater the required torque Treq.
[0021] The control amount calculation portion 22 calculates a target torque Ttgt by adding the margin torque Tm to the required torque Treq. The control amount calculation portion 22 calculates a target load factor KLtgt by applying the calculated target torque Ttgt to a lookup table MapKLtgt(Ttgt) that is calculated in advance on the premise that the air-fuel ratio is the stoichiometric air-fuel ratio and the ignition timing is the MBT. Further, the load factor is a ratio of the in-cylinder intake air amount to a maximum in-cylinder intake air amount determined in accordance with the engine speed NE. Also, the control amount calculation portion 22 calculates a target throttle opening TAtgt by applying the calculated target load factor KLtgt and the detected engine speed NE to a lookup table MapTAtgt(KLtgt, NE) that is calculated in advance.
[0022] The control amount calculation portion 22 calculates an ignition timing SA by applying the calculated required torque Treq, the calculated target load factor KLtgt, and the detected engine speed NE to a lookup table MapSA(Treq, KLtgt, NE) that is calculated in advance. As a result, the ignition timing SA is retarded by an amount corresponding to the margin torque Tm. In addition to this, the control amount calculation portion 22 calculates a fuel injection amount Finj that is required in order to make the air-fuel ratio of the mixture taken into the engine 10 coincide with the stoichiometric air-fuel ratio, on the basis of the detected intake air amount Ga and the detected engine speed NE, and so on.
[0023] The actuator drive portion 23 drives the fuel injection valve 11 in such a manner that the fuel injection amount Finj calculated by the control amount calculation portion 22 is injected from the fuel injection valve 11. The actuator drive portion 23 controls the ignition device 12 in such a manner that ignition is performed at the ignition timing SA calculated by the control amount calculation portion 22. The actuator drive portion 23 drives the throttle motor 13 in such a manner that the actual throttle opening coincides with the target throttle opening TAtgt calculated by the control amount calculation portion 22.
[0024] The engine torque estimation portion 24 estimates the torque (engine torque) Tact that is actually generated by the engine 10 by applying the detected "engine speed NE, intake air amount Ga, and air-fuel ratio AF" to a lookup table MapTact(NE, Ga, AF) that is determined in advance.
[0025] The excess torque calculation portion 25 calculates an excess torque Qex by subtracting the required torque Treq from the engine torque Tact. As will be described in detail later, the excess torque Qex is a torque that is generated by the engine 10 in excess of the required torque Treq. Figure 2 As will be described in detail later, the abnormality determination threshold value calculation portion 26 calculates (determines) a torque deviation threshold value Qth and a duration threshold value Tth on the basis of the accelerator pedal operation amount AP.
[0026] When the excess torque Qex is larger than the torque deviation threshold value Qth for a duration longer than the duration threshold value Tth, the abnormality determination part 27 determines that the internal combustion engine 10 is in an abnormal state in which an excess torque is generated. When the abnormality determination part 27 determines that the internal combustion engine 10 is in an abnormal state in which an excess torque is generated, the abnormality determination part 27 causes the warning buzzer of the warning device 30 to sound, causes the warning light of the warning device 30 to light, and causes the fail-safe execution part 28 to operate.
[0027] The fail-safe execution part 28 sends a command signal to the actuator driving part 23 to cause the internal combustion engine 10 to generate a small torque. As a result, the throttle valve is changed to the fully closed state by driving the throttle motor 13 with the actuator driving part 23, and the ignition timing is maintained at the fixed ignition timing. In addition, the fuel injection amount is set to the fuel injection amount Finj calculated by the control amount calculation part 22.
[0028] However, the required torque Treq is required to change in accordance with the accelerator pedal operation amount AP. Therefore, when deceleration operation is performed to generate a deceleration state in which the accelerator pedal operation amount AP is abruptly reduced from a certain value to "0", the required torque Treq is also required to be abruptly reduced. Therefore, the opening degree of the throttle valve is also abruptly reduced. However, the intake air amount Ga is reduced with a delay with respect to the change in the accelerator pedal operation amount AP due to the response delay of the intake air, and therefore, the torque generated by the internal combustion engine 10 is also reduced with a delay with respect to the change in the accelerator pedal operation amount AP. That is, the internal combustion engine 10 has a response delay with respect to the change in the required torque. Therefore, in the case where deceleration operation is present, the excess torque Qex temporarily becomes large, and therefore, the abnormality determination part 27 can erroneously determine that the internal combustion engine 10 is in an abnormal state. Therefore, the abnormality determination threshold value calculation part 26 (hereinafter, referred to as "threshold value calculation part 26") changes the torque deviation threshold value Qth and the duration threshold value Tth in a manner corresponding to the response delay of the internal combustion engine 10 in the case where it is determined that it is a deceleration state.
[0029] More specifically, as shown in FIG. 6, the threshold value calculation part 26 calculates a "smoothed required torque Trb" by performing "delay processing Bl corresponding to the response delay of the internal combustion engine 10 and smoothing processing (substantially low-pass filter processing) B2" on the required torque Treq. Figure 2
[0030] In addition, in the present embodiment, the delay processing means that a variable z (t - Δt) that is the variable z at a time point t - Δt that is a predetermined time Δt before the current time point t is used as the variable z with respect to the variable z (t). Δt is a suitable value. Furthermore, in the present embodiment, the smoothing processing means that Y (n) obtained by performing processing on the current value X (n) of the variable X based on the following equation is used instead of the variable X. Y (n - 1) is the previous value of Y (n). a is a suitable value that is larger than "0" and smaller than "1".
[0031] Y(n) = a • Y(n - 1) + (1 - a) • X(n)
[0032] The threshold operation section 26 calculates the difference dT by performing the difference process B3 of subtracting the required torque Treq from the smoothed required torque Trb, and performs the comparison process B4 to generate the determination result in the deceleration state when the difference dT is positive. For example, as shown in the block TM, if the accelerator pedal operation amount AP is sharply reduced at the time tl, the difference dT is positive during the period from the time tl to the time t3, so it is determined that the deceleration state occurs during the period from the time tl to the time t3. Figure 2
[0033] On the other hand, the threshold operation section 26 obtains the reference value QthO of the torque deviation threshold value by applying the accelerator pedal operation amount AP to the lookup table MapQ(AP) illustrated in the block B5. According to the table MapQ(AP), the greater the accelerator pedal operation amount AP, the greater the torque deviation threshold value reference value QthO. Further, the threshold operation section 26 obtains the "smoothed torque deviation threshold value Qblr" by performing the "delay process B6 and the smoothing process B7 corresponding to the response delay of the internal combustion engine 10" on the torque deviation threshold value reference value QthO. Also, the threshold operation section 26 determines the "smoothed torque deviation threshold value Qblr" as the final torque deviation threshold value Qth and outputs it in the case where the determination result in the deceleration state is obtained by the first selection section B8, and determines the "torque deviation threshold value reference value QthO" as the final torque deviation threshold value Qth and outputs it in the case where the determination result in the deceleration state is not obtained.
[0034] Similarly, the threshold operation section 26 obtains the duration threshold value reference value TthO by applying the accelerator pedal operation amount AP to the lookup table MapT(AP) illustrated in the block B9. According to the table MapT(AP), the greater the accelerator pedal operation amount AP, the greater the duration threshold value reference value TthO. Further, the threshold operation section 26 obtains the "smoothed duration threshold value reference value Tblr" by performing the "delay process B10 and the smoothing process Bll corresponding to the response delay of the internal combustion engine 10" on the duration threshold value reference value TthO. Also, the threshold operation section 26 determines the "smoothed duration threshold value reference value Tblr" as the final duration threshold value Tth and outputs it in the case where the determination result in the deceleration state is obtained by the second selection section B12, and determines the "duration threshold value reference value TthO" as the final duration threshold value Tth and outputs it in the case where the determination result in the deceleration state is not obtained.
[0035] As a result, even in a case where the excess torque Qex temporarily becomes large due to a response delay of the internal combustion engine 10 when the accelerator pedal operation amount AP sharply decreases, the excess torque Qex is less likely to become larger than the torque deviation threshold Qth, and, assuming that the excess torque Qex becomes larger than the torque deviation threshold Qth, the state is less likely to continue for a duration longer than the duration threshold Tth. Therefore, it is possible to reduce the possibility of erroneously determining that the internal combustion engine 10 is in an abnormal state.
[0036] Next, the specific operation of the CPU of the engine ECU 20 will be described. The CPU executes the routine shown in the flowchart below every predetermined time. Therefore, when it becomes the predetermined timing, the CPU starts the process from step (hereinafter, described as "S") 300 and proceeds to S305, and determines whether or not the value of the abnormality determination flag Xab is "0". The abnormality determination flag Xab indicates that the internal combustion engine 10 is determined to be in an abnormal state where excess torque is generated when the value thereof is "1". Further, the value of the abnormality determination flag Xab is stored in the nonvolatile memory. Figure 3 Figure 3 In a case where the value of the flag Xab is not "0", the CPU proceeds to S395 after executing the process of S360 described later, and temporarily ends the present routine. In contrast, in a case where the value of the flag Xab is "0", the CPU executes the process of "S310 to S330" described below and proceeds to S335.
[0037] S310: The CPU acquires the required torque Treq as described above.
[0037] S315: The CPU acquires the engine torque Tact as described above.
[0038] S320: The CPU acquires the excess torque Qex as described above.
[0038] S325: The CPU reads in the torque deviation threshold Qth determined as described above.
[0039] S330: The CPU reads in the duration threshold Tth determined as described above.
[0039] S335: The CPU determines whether or not the excess torque Qex is larger than the torque deviation threshold Qth.
[0040] S340: The CPU determines whether or not the state where the excess torque Qex is larger than the torque deviation threshold Qth has continued for a duration longer than the duration threshold Tth.
[0040] S345: The CPU determines whether or not the value of the abnormality determination flag Xab is "0".
[0041] S350: The CPU determines whether or not the value of the abnormality determination flag Xab is "0".
[0041] S355: The CPU determines whether or not the value of the abnormality determination flag Xab is "0".
[0042] S360: The CPU determines whether or not the value of the abnormality determination flag Xab is "0".
[0042] S365: The CPU determines whether or not the value of the abnormality determination flag Xab is "0".
[0043] The CPU determines in S335 whether the excess torque Qex is greater than the torque deviation threshold Qth, and in the case where the excess torque Qex is greater than the torque deviation threshold Qth, increments the value of the timer T by only "1" in S340. Next, the CPU proceeds to S345 and determines whether the value of the timer T is greater than the duration threshold Tth. In the case where the value of the timer T is greater than the duration threshold Tth, the CPU determines that the internal combustion engine 10 is in an abnormal state and sets the value of the abnormality determination flag Xab to "1" in S350. Thereafter, the CPU performs the above-described fail-safe processing in S355 and proceeds to S395, temporarily ending this routine.
[0044] Further, in the case where the CPU determines "No" in S335, it proceeds to S360 and sets the value of the timer T to "0", and thereafter proceeds to S395.
[0045] As explained above, the device changes the torque deviation threshold Qth and the duration threshold Tth to correspond to the response delay of the internal combustion engine 10 caused by the response delay of the intake air in the deceleration state in which the accelerator pedal operation amount is reduced. Therefore, the excess torque Qex is less likely to become greater than the torque deviation threshold Qth, and even if the excess torque Qex becomes greater than the torque deviation threshold Qth, this state is less likely to continue for the duration threshold Tth or more. Therefore, the device can reduce the possibility of erroneously determining that the internal combustion engine 10 is in an abnormal state in which the excess torque is continuously generated when the deceleration state occurs.
[0046] In addition, the present application is not limited to the above-described embodiment, and various modifications can be adopted within the scope of the present application. For example, the duration threshold reference value TthO which does not perform the delay smoothing processing can be adopted as the duration threshold Tth at all times.
[0047] [Legend of Reference Numerals]
[0048] 10... internal combustion engine, 20... engine ECU, 26... abnormality determination threshold operation section, 27... abnormality determination section.
Claims
1. An abnormality determination device for an internal combustion engine, comprising: a control unit that controls the internal combustion engine to generate a torque equal to a required torque determined based on an accelerator pedal operation amount; and an abnormality determination unit that estimates the actual torque generated by the internal combustion engine as the internal combustion engine torque, and determines that the internal combustion engine is in an abnormal state when an excess torque state occurs that is greater than a torque deviation threshold, wherein the excess torque is the excess amount of the internal combustion engine torque relative to the required torque, wherein... The internal combustion engine anomaly detection device includes a threshold calculation unit, which is configured to... Based on the difference between the required torque and the smoothed required torque, it is determined whether the internal combustion engine is in a deceleration state. The smoothed required torque is the required torque that has undergone a delay smoothing process that is equivalent to the response delay of the internal combustion engine relative to the change in the required torque. The reference value for calculating the torque deviation threshold is based on the accelerator pedal operation amount; If it is determined that the internal combustion engine is not in the deceleration state, the reference value is determined as the torque deviation threshold. When it is determined that the internal combustion engine is in the deceleration state, the smoothed torque deviation threshold is determined as the torque deviation threshold. The smoothed torque deviation threshold is the torque deviation threshold for which a delay smoothing process equivalent to the response delay of the internal combustion engine has been applied to the reference value.
Citation Information
Patent Citations
Engine control device
JP2017014972A