JP2019056304A - Abnormality detection device and control device for combustion system - Google Patents

Abstract

To provide an abnormality detection device and a control device for a combustion system capable of appropriately detecting an abnormality in an internal combustion engine and purging fuel gas generated by evaporation of fuel.SOLUTION: A combustion system 10 includes an engine 11, an air-fuel ratio sensor 18, a purge device 22 and an ECU 30. The purge device 22 enables fuel gas that is gas generated by evaporation of fuel to be supplied from a fuel tank 21 to an intake passage 12. The ECU 30 executes air-fuel ratio feedback control for controlling an air-fuel ratio of the engine, purge control for controlling gas purge for supplying fuel gas to the engine 11, and abnormality detection processing for detecting occurrence of an abnormality in the combustion system 10. In the abnormality detection processing, both of whether the gas purge is prohibited and whether an abnormality occurs are made by using a correction parameter indicating a correction form of the air-fuel ratio in the air-fuel ratio feedback control.SELECTED DRAWING: Figure 1

Description

  The disclosure according to this specification relates to an abnormality detection device and a control device for a combustion system.

  As a technique for controlling the air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine, for example, Patent Document 1 discloses a technique for performing a learning process for learning a correction value for controlling the air-fuel ratio. Patent Document 1 also discloses a technique of performing a gas purge for supplying the fuel gas to the internal combustion engine when the fuel gas, which is a gas obtained by evaporating the fuel, is generated in the fuel tank. In this Patent Document 1, the learning process is not performed during the gas purge, and the gas purge is not performed during the learning process, so that the air-fuel ratio fluctuates from the fuel gas 2 supplied to the internal combustion engine by the gas purge. Thus, it is possible to suppress a decrease in the learning accuracy of the correction value.

  Patent Document 2 discloses a technique in which the internal combustion engine is not stopped until correction value learning is completed in a vehicle such as a hybrid vehicle that temporarily stops the operation of the internal combustion engine. In Patent Document 2, even when a vehicle in which the correction value can be learned is shortened compared to a vehicle in which the operation of the internal combustion engine is not temporarily stopped, the correction value is learned as the internal combustion engine is stopped. It is said that it can suppress that it is not performed properly.

JP2012-2151A Japanese Patent No. 3141823

  Here, assuming that an abnormality detection process for detecting an abnormality related to the internal combustion engine is performed, in order to optimize the detection accuracy, the abnormality detection process is not overlapped with the gas purge as in the learning process of the first embodiment. It is thought that it is necessary to execute as follows. When the configuration in which the abnormality detection process and the gas purge are not overlapped with each other is applied to a configuration in which the operation time of the internal combustion engine is relatively short as in Patent Document 2, the abnormality detection process is performed. For this reason, it is assumed that there is a shortage of time for learning and for performing learning processing. For example, if the abnormality detection process is performed with priority over the gas purge as in the learning process of Patent Document 2, there is a concern that the fuel gas leaks due to insufficient time for performing the gas purge. On the other hand, if the gas purge is executed with priority over the abnormality detection process, there is a concern that the time for performing the abnormality detection process is insufficient and the discovery of the abnormality is delayed.

  A main object of the present disclosure is to provide an abnormality detection device and a combustion system control device capable of appropriately performing both abnormality detection related to an internal combustion engine and purging of fuel gas generated along with fuel evaporation. is there.

In order to achieve the above object, the disclosed first aspect is:
An abnormality detection device (30) for detecting an abnormality in a combustion system (10) having an internal combustion engine (11) for burning fuel,
In the air-fuel ratio control for controlling the air-fuel ratio of the exhaust gas discharged from the internal combustion engine, a gas purge for supplying the internal combustion engine with a fuel gas, which is a gas evaporated from the fuel, is performed based on a correction parameter (HP) indicating a correction mode of the air-fuel ratio A restriction determination unit (S106, S108) for determining whether to restrict;
An abnormality determining unit (S202, S204, S207, S207) that determines whether an abnormality has occurred in the combustion system based on the correction parameter when it is determined by the restriction determining unit that the gas purge is restricted and the gas purge is in a stopped state. S302, S304, S307, S401, S403, S406),
Is an abnormality detection device.

  When an abnormality occurs in the combustion system in which an actuator that adjusts the air-fuel ratio does not operate normally, it is assumed that the air-fuel ratio control is not performed properly. In this case, since the correction parameter used for the air-fuel ratio control shows an abnormal change mode, the accuracy of the abnormality determination can be increased by using the correction parameter as in the first mode.

  Here, it is assumed that the air-fuel ratio is likely to fluctuate due to the influence of the fuel gas during the purge of the fuel gas. For this reason, it is considered difficult to accurately determine the abnormality of the combustion system using the correction parameter of the air-fuel ratio control, but if the determination accuracy may be low to the extent that it may be abnormal, the correction parameter It is possible to make an abnormality determination using. Therefore, according to the first aspect, since the restriction determination as to whether or not to restrict the gas purge is performed, this restriction determination can be used as an abnormality determination with relatively low determination accuracy. For this reason, when an abnormality may have occurred in the combustion system, an abnormality determination with a relatively high determination accuracy can be performed again while the gas purge is regulated. In this case, abnormality detection is prioritized over gas purge, so that it is possible to suppress delay in discovery of abnormality due to insufficient time for performing abnormality detection. On the other hand, if the possibility of occurrence of an abnormality is so low that it is denied even in the regulation judgment, the gas purge is performed with priority over the detection of the abnormality, so that the time for performing the gas purge is insufficient. Thus, it is possible to prevent the fuel gas from leaking.

  As described above, both abnormality detection and purge of fuel gas relating to the internal combustion engine can be properly performed.

The second aspect is
A control device (30) for controlling the operation of a combustion system (10) having an internal combustion engine (11) for burning fuel,
In the air-fuel ratio control for controlling the air-fuel ratio of the exhaust gas discharged from the internal combustion engine, a gas purge for supplying the internal combustion engine with a fuel gas, which is a gas evaporated from the fuel, is performed based on a correction parameter (HP) indicating a correction mode of the air-fuel ratio. A restriction determination unit (S106, S108) for determining whether to restrict;
A regulation execution unit (S110) that regulates the gas purge when it is judged by the regulation judgment unit to regulate the gas purge;
An abnormality determination unit (S202, S204, S207, S302, S304, S307) that determines whether an abnormality has occurred in the combustion system based on the correction parameter when the execution of gas purge is restricted by the restriction execution unit. , S401, S403, S406),
It is a control device of a combustion system provided with.

  According to the second aspect, when the abnormality may have occurred in the combustion system, the gas purge is regulated by the regulation execution unit, so that the same effect as in the first embodiment can be obtained.

  It should be noted that the reference numerals in parentheses described in the claims and in this section merely indicate correspondence with specific means described in the embodiments described later, and do not limit the technical scope of the present disclosure. Absent.

Schematic which shows the structure of the combustion system in 1st Embodiment. The figure for demonstrating the correction range. The flowchart which shows the procedure of an abnormality detection process. The flowchart which shows the procedure of this abnormality process. The time chart for demonstrating the abnormality detection process in case the lean abnormality has generate | occur | produced. The time chart for demonstrating the abnormality detection process in case rich abnormality has generate | occur | produced. The flowchart which shows the procedure of this abnormality process in 2nd Embodiment. The flowchart which shows the procedure of a rich process. The time chart for demonstrating the abnormality detection process in case correction | amendment of an air fuel ratio is lean correction. The time chart for demonstrating the abnormality detection process in case correction | amendment of an air fuel ratio is rich correction.

  Hereinafter, a plurality of embodiments of the present disclosure will be described based on the drawings. In addition, the overlapping description may be abbreviate | omitted by attaching | subjecting the same code | symbol to the corresponding component in each embodiment. When only a part of the configuration is described in each embodiment, the configuration of the other examples described above can be applied to other portions of the configuration. Moreover, not only the combination of the configurations explicitly described in the description of each embodiment, but also the configuration of a plurality of embodiments can be partially combined even if they are not explicitly described, as long as there is no problem in the combination. And the combination where the structure described in several embodiment and the modification is not specified shall also be disclosed by the following description.

(First embodiment)
A combustion system 10 shown in FIG. 1 includes an engine 11, an intake passage 12, an exhaust passage 13, an air flow meter 14, a throttle valve 15, an injector 16, an exhaust purification device 17, and an air-fuel ratio sensor 18, for example, mounted on a vehicle. Has been. The engine 11 is an internal combustion engine such as a spark ignition gasoline engine, and the intake passage 12 supplies intake air such as outside air to the combustion chamber 11 a of the engine 11. The air flow meter 14 is provided in the intake passage 12 and detects the flow rate of intake air flowing through the intake passage 12. The throttle valve 15 is an on-off valve provided on the downstream side of the air flow meter 14 in the intake passage 12, and the opening degree with respect to the intake passage 12 can be changed.

  The injector 16 is a fuel injection valve provided closer to the engine 11 than the throttle valve 15, and injects fuel in the vicinity of the intake port of each cylinder in the intake passage 12. The engine 11 is provided with a spark plug (not shown), and in the combustion chamber 11a, a mixture of intake air and fuel is ignited by the spark plug. In the present embodiment, an intake port injection type engine is used, and the injector 16 is configured to inject fuel into the intake passage 12, but instead, a direct injection type engine is used and the injector 16 burns. It is good also as a structure which injects a fuel into the chamber 11a.

The exhaust passage 13 discharges exhaust from the engine 11. The exhaust purification device 17 has a three-way catalyst that purifies CO, HC, NOx and the like contained in the exhaust, and is provided in the exhaust passage 13. The air-fuel ratio sensor 18 is an air-fuel ratio detection unit that detects the air-fuel ratio of the exhaust, and is provided upstream of the exhaust purification device 17 in the exhaust passage 13. The air-fuel ratio sensor 18 is an O ₂ sensor that generates different electromotive force depending on whether the air-fuel ratio is rich or lean. The air-fuel ratio sensor 18 may be a wide area detection type A / F sensor that outputs a wide area signal corresponding to the oxygen concentration in the exhaust gas. Further, the air-fuel ratio sensor 18 may be provided on both the upstream side and the downstream side of the exhaust purification device 17, or may be provided only on the downstream side.

  The combustion system 10 includes a fuel tank 21 that stores the fuel supplied to the injector 16 and a purge device 22 that purges the fuel gas, which is a gas evaporated from the fuel, from the fuel tank 21. The combustion system 10 has a fuel supply system that supplies fuel to the engine 11, and this fuel supply system includes an injector 16, a fuel tank 21, a fuel supply pipe, and a fuel pump. The fuel in the fuel tank 21 is supplied to the injector 16 through the fuel supply pipe when the fuel pump is driven.

  The fuel gas purged by the purge device 22 is discharged from the fuel tank 21 and supplied to the engine 11. Hereinafter, the purge of the fuel gas is also referred to as a gas purge. The purge device 22 has a purge passage 23, a canister 24, and a purge valve 25. The purge passage 23 connects the fuel tank 21 and the intake passage 12 and supplies fuel gas from the fuel tank 21 to the intake passage 12. The canister 24 has an adsorbent such as activated carbon and is provided at an intermediate position of the purge passage 23 so that the fuel gas can be adsorbed by the adsorbent or the like. The purge valve 25 is an open / close valve provided in the purge passage 23 on the downstream side of the canister 24. The fuel gas adsorbed by the canister 24 is supplied to the intake passage 12 when the purge valve 25 is open. On the other hand, when the purge valve 25 is in the closed state, the supply of the fuel gas to the intake passage 12 is stopped.

  The combustion system 10 includes an ECU 30 as a control device that controls the operation of the combustion system 10. The ECU (Engine Control Unit) 30 includes a computer that includes a processor 30a, a storage unit 30b, an input / output interface, and the like. Examples of the storage unit 30b include a RAM and a storage medium. A program for controlling the operation of the engine 11 and a program for detecting an abnormality of the combustion system 10 are stored in the storage unit 30b, and these programs are executed by the processor 30a. The storage unit 30b also stores various data used when performing abnormality detection.

  The ECU 30 is electrically connected to actuators such as the throttle valve 15, the injector 16, and the purge valve 25, and controls the operation of these actuators by outputting a command signal. The ECU 30 is electrically connected to various sensors such as the air flow meter 14 and the air-fuel ratio sensor 18, and these various sensors output detection signals to the ECU 30.

  The ECU 30 performs a process for controlling the fuel injection amount. In this process, the basic injection amount is calculated from the intake air amount of the engine 11, and various corrections are performed on the basic injection amount to calculate the final injection amount. In the present embodiment, the correction amount and the learning value are calculated for the feedback control of the fuel injection amount, and the final injection amount is calculated using the correction amount and the learning value in addition to the basic injection amount. Then, the final injection amount is converted into an injection time, and the injector 16 is opened based on the converted injection time. When the learning value is a relative value based on the basic injection amount, the final injection amount is calculated by adding the correction amount and the learning value to the basic injection amount.

  The ECU 30 performs a process of controlling the air-fuel ratio of the exhaust as one of various corrections of the fuel injection amount. In this process, the air-fuel ratio feedback control is performed using the air-fuel ratio detection value detected by the air-fuel ratio sensor 18 so that the actual air-fuel ratio of the exhaust gas matches the target air-fuel ratio such as the stoichiometric air-fuel ratio. Do. In the present embodiment, in the air-fuel ratio feedback control, a feedback amount that is compared with the target air-fuel ratio in order to calculate a deviation is referred to as a correction amount. In the air-fuel ratio feedback control, the feedback amount is learned using the correction amount, and the reference value of the feedback amount updated by the learning is referred to as a learned value.

  The correction amount is a short term parameter that compensates for a change in the response characteristic of the actual air-fuel ratio with respect to a parameter that changes in the short term, such as intake air temperature or atmospheric pressure. On the other hand, the learning value is a long term parameter that compensates for a change in the response characteristic of the actual air-fuel ratio with respect to a parameter that changes in the long term, such as a secular change of the throttle valve 15. Both the correction amount and the learning value are parameters used for correcting the air-fuel ratio in the air-fuel ratio feedback control.

  In the air-fuel ratio feedback control, the correction amount is limited, and the correction amount limiting mode is changed by correcting the learning value. In FIG. 2, the correction amount HPa is the feedback amount in the air-fuel ratio feedback control, and the learning value HPb is the reference value of the feedback amount. For the correction amount HPa, a correction range CR is set as a correctable range. The feedback center value CR0 indicating the center of the correction range CR is a value serving as a reference for the correction amount HPa, and is changed as the learning value HPb is corrected. When the feedback center value CR0 is changed, the correction upper limit value CR1 that is the upper limit value of the correction range CR and the correction lower limit value CR2 that is the lower limit value are also changed. However, regarding the correction range CR, the maximum correction width, which is a value obtained by subtracting the correction lower limit value CR2 from the correction upper limit value CR1, is not changed even when the feedback center value CR0 is corrected, and is always a predetermined width. When the feedback center value CR0 is used as a reference, the absolute values of the correction upper limit value CR1 and the correction lower limit value CR2 are the same value.

  The feedback center value CR0 coincides with the feedback initial value IV0, which is the initial value of the feedback center value CR0, when the learning value HPb is not corrected, and is corrected to the feedback initial value IV0 by correcting the learning value HPb. Will have different values. The correction amount HPa is a value based on the feedback center value CR0, and the learning value HPb is a value based on the feedback initial value IV0. Further, when the sum of the correction amount HPa and the learning value HPb is referred to as a determination index HP, the determination index HP is a value based on the feedback initial value IV0 as in the case of the learning value HPb. The correction amount HPa and the learning value HPb indicate the correction mode of the air-fuel ratio in the air-fuel ratio feedback control, and the determination index HP including the correction amount HPa and the learning value HPb corresponds to a correction parameter.

  In this embodiment, the feedback initial value IV0 is set to zero, and the correction amount HPa and the learning value HPb increase when the actual air-fuel ratio is corrected to the lean side, and the actual air-fuel ratio is corrected to the rich side. To decrease. Here, when the correction amount HPa increases, the learning value HPb is corrected so as to increase. On the other hand, when the correction amount HPa decreases, the learning value HPb is corrected so as to decrease.

  As for the learning value HPb, the learning range is set as a learning range as in the correction range CR of the correction amount HPa, and the center value of the learning range is the feedback initial value IV0. The learning upper limit value LR1 (see FIG. 5) that is the upper limit value of the learning range is a positive value larger than the feedback initial value IV0, and the learning lower limit value LR2 (see FIG. 6) that is the lower limit value of the learning value is The negative value is smaller than the initial feedback value IV0.

  Returning to the description of FIG. 1, the ECU 30 performs purge control for controlling gas purge by the purge device 22. In this process, on condition that the engine 11 is in an operating state, the purge valve 25 is shifted to an open state when a predetermined start condition is satisfied, and the purge valve 25 is continuously opened until a predetermined purge time has elapsed. Keep in state. The start condition includes at least one of, for example, the end of the warm-up operation of the engine 11 and the elapse of a predetermined time since the previous gas purge. The purge time may be set to the same time for each gas purge, or may be variably set according to the operating state of the engine 11, the outside air temperature, and the like.

  Further, the ECU 30 performs idle stop control for controlling idle stop for the engine 11. In this process, when the engine 11 is idling, the engine 11 is stopped when a predetermined idle stop condition is satisfied, and then the engine 11 is restarted when a predetermined idle restart condition is satisfied. The idle stop condition includes, for example, at least one of the fact that the accelerator operation amount has become zero, that the brake pedal has been depressed, the vehicle speed has decreased to a predetermined value, or the like. The idle restart condition includes, for example, at least one of an accelerator operation performed when the engine is stopped and a brake pedal being released.

  In addition, the ECU 30 performs an abnormality detection process for detecting an abnormality in the combustion system 10. Abnormalities in the combustion system 10 detected by this processing include fuel system abnormalities such as injector 16 and fuel pump malfunctions, air system abnormalities such as throttle valve 15 and air flow meter 14 malfunctions, and air-fuel ratio sensor 18 malfunctions. Exhaust system abnormalities are listed. When the injector 16 or the fuel pump does not operate normally due to a failure or the like, it is assumed that the actual injection amount of the fuel actually injected from the injector 16 is too much or too little with respect to the command value. When the throttle valve 15 does not open and close normally due to a failure or the like, it is assumed that the intake air amount supplied to the combustion chamber 11a is too much or too little with respect to the command value. When an abnormality occurs in the fuel system or the air system as described above, the air-fuel ratio tends to be excessive or excessive due to the fuel injection amount or the intake air amount being too large or too small. Note that the ECU 30 corresponds to an abnormality detection device.

  Here, the abnormality detection process will be described with reference to the flowchart of FIG.

  In FIG. 3, in step S101, it is determined whether air-fuel ratio feedback control is being executed. Here, at least one of the fact that the engine is being started, the fuel injection amount is at a minimum amount during idle operation, or that the fuel injection amount is zero at the time of deceleration, etc. It is determined whether it is established. If at least one is satisfied, the process proceeds to step S114 because the air-fuel ratio feedback control is not being executed, and if none is satisfied, the process proceeds to step S102 because the air-fuel ratio feedback control is being executed. .

  In step S102, it is determined whether the actual injection amount is included in the allowable range. Here, for the fuel injection amount, an allowable range of the actual injection amount is set with respect to the command value, and when the actual injection amount is larger than the allowable range, the actual injection amount is excessive with respect to the command value, and the actual injection amount is When it is smaller than the allowable range, it is determined that the actual injection amount is too small with respect to the command value. In this determination process, it is determined whether or not there is a possibility that an abnormality has occurred in the fuel system of the combustion system 10. If the actual injection amount is not within the allowable range, an abnormality has occurred in the fuel system of the combustion system 10. Since there is a possibility of having performed, it progresses to step S103.

  In step S103, the correction amount HPa is acquired for the air-fuel ratio feedback control, and in step S104, the learning value HPb is acquired. In step S105, the determination index HP is calculated by adding the correction amount HPa and the learning value HPb. The determination index HP has both short-term and long-term elements, and corresponds to a correction parameter related to air-fuel ratio correction in air-fuel ratio feedback control.

  In steps S106 to S111, a temporary abnormality process is performed in which it is determined whether to prohibit the gas purge based on the determination index HP. In the temporary abnormality process, in step S106, it is determined whether or not the absolute value of the determination index HP is larger than the temporary determination value D1. The provisional determination value D1 is set to an absolute value of a value included in the correction range CR when the feedback center value CR0 matches the feedback initial value IV0. Here, when the correction range CR when the feedback center value CR0 matches the feedback initial value IV0 is referred to as a limit range CRa, the provisional determination value D1 is smaller than the correction upper limit value CR1 and the correction lower limit value for the limit range CRa. It is smaller than the absolute value of CR2. Note that the air-fuel ratio is determined to be lean when the determination index HP is larger than the initial feedback value IV0, and rich when it is smaller than the initial feedback value IV0.

  If the absolute value of the determination index HP is larger than the provisional determination value D1, it is determined that there is a possibility that an abnormality may occur to some extent because it is necessary to monitor the change mode of the determination index HP. Is determined to be out of the allowable range of the temporary abnormality. In step S107, the temporary abnormality timer p set in the storage unit 30b or the like is incremented. Here, the duration for which the absolute value of the determination index HP is larger than the temporary determination value D1 is measured.

  In step S108, it is determined whether or not the temporary abnormality timer p is greater than a predetermined temporary continuation determination value N1. When a state where the absolute value of the determination index HP is larger than the temporary determination value D1 is referred to as a temporary determination state, here, the duration during which the determination index HP is in the temporary determination state is a predetermined temporary determination time Ta (see FIG. 5). ) It is determined whether or not it has become longer. In addition, each determination of step S106, S108 can be collectively called temporary abnormality determination. Further, the temporary determination state corresponds to the restriction determination state, the temporary determination value D1 corresponds to the restriction determination value, and the temporary determination time Ta corresponds to the restriction determination time.

  On the other hand, if the absolute value of the determination index HP is not larger than the provisional determination value D1, the process proceeds to step S109, and the provisional abnormality timer p is set to zero because the possibility of occurrence of abnormality is not high enough to monitor the change mode of the determination index HP To clear.

  If it is determined in step S108 that the temporary abnormality timer p is greater than the temporary continuation determination value N1, it is determined that the change mode of the determination index HP is out of the temporary abnormality allowable range, and the process proceeds to step S110. In step S110, a purge prohibition request is issued to prohibit gas purge. Here, by outputting a prohibition signal to the purge device 22, the purge valve 25 is moved to the closed state or held. For example, when the gas purge is being performed, the purge is stopped by moving the purge valve 25 to the closed state, and the purge is not resumed by holding the purge valve 25 until the purge prohibition request is released. On the other hand, when the gas purge is not performed, the purge valve 25 is kept closed until the purge prohibition request is canceled, so that a new gas purge is not started.

  On the other hand, if the provisional abnormality timer p is not greater than the provisional continuation determination value N1, it is determined that the change mode of the determination index HP has not deviated from the provisional abnormality allowable range, and the process proceeds to step S111. In step S111, the purge prohibition request is canceled. Here, the purge valve 25 is permitted to shift to the open state by outputting a cancel signal for canceling the purge prohibition request to the purge device 22. For example, when the gas purge is stopped due to the purge prohibition request, the gas purge is restarted by returning the purge valve 25 to the open state.

  After the provisional abnormality process in steps S106 to S111 is completed, the process proceeds to step S112 to perform this abnormality process. This abnormality process will be described with reference to the flowchart of FIG.

  In FIG. 4, in step S201, it is determined whether or not the gas purge is stopped. Examples of the case where the gas purge is stopped include a case where the gas purge is stopped due to a purge prohibition request, and a case where it is not necessary to perform the gas purge.

  When the gas purge is in a stopped state, it is determined that the gas purge is not performed, and the process proceeds to step S202, where it is determined whether or not the absolute value of the determination index HP is greater than the determination value D2. This determination value D2 is set to an absolute value that is a positive value that is so large that it is not included in the restriction range CRa in the correction range CR or a small negative value. In this case, the determination value D2 is larger than the correction upper limit value CR1 and larger than the absolute value of the correction lower limit value CR2 in the limit range CRa. Here, as in the case of the provisional abnormality process, if the determination index HP is larger than the feedback initial value IV0, it is determined to be lean, and if it is smaller, it is determined to be rich.

  When the absolute value of the determination index HP is larger than the determination value D2, it is assumed that the possibility of occurrence of an abnormality is high enough that the change mode of the determination index HP needs to be monitored in a state where the gas purge is not performed, and steps S203 to S207 are performed. Perform the process. In steps S203 to S207, it is determined whether or not the change mode of the determination index HP is out of the allowable range of the abnormality. A state where the absolute value of the determination index HP is greater than the main determination value D2 is referred to as a main determination state. Here, the duration of the determination index HP in the main determination state is a predetermined main determination time Tb (see FIG. 5). ) Judge whether or not it has become longer. The main determination time Tb is set to be longer than the temporary determination time Ta. Thereby, after the result of the determination using the provisional determination time Ta is obtained, the result of the determination using the main determination time Tb is output.

  Note that the determinations of steps S202, S204, and S207 can be collectively referred to as the present abnormality determination. Further, the main determination state corresponds to the abnormality determination state, the main determination value D2 corresponds to the abnormality determination value, and the main determination time Tb corresponds to the abnormality determination time.

  First, in step S203, the abnormality timer q set in the storage unit 30b or the like is incremented. Here, the continuation time in which the absolute value of the determination index HP is larger than the determination value D2 is measured. In step S204, it is determined whether the abnormality timer q is greater than a predetermined continuation determination value N2. The continuation determination value N2 is set to a value smaller than the temporary continuation determination value N1, for example.

  If the abnormality timer q is greater than the main continuation determination value N2, the process proceeds to step S205, and the number of times set in the storage unit 30b or the like to count the number of times that the abnormality timer q is greater than the main continuation determination value N2. Increment the counter u. In step S206, the abnormality timer q is cleared to zero so that the time measurement by the abnormality timer q can be performed again.

  In step S207, it is determined as a main abnormality determination whether the main counter u is larger than a predetermined main abnormality determination number N3. This abnormality determination number N3 is set to 3 times, for example.

  If the main counter u is larger than the main abnormality determination number N3, it is determined that the change mode of the determination index HP is out of the allowable range of the main abnormality, and the process proceeds to step S208. In step S208, it is determined that an abnormality has occurred in the combustion system 10, and abnormality countermeasure processing is performed. Here, processing for prohibiting air-fuel ratio feedback control, processing for notifying that an abnormality has occurred in the combustion system 10, and the like are performed. Further, the provisional abnormality timer p, the present abnormality timer q, and the number-of-times counter u are cleared to zero in preparation for the case where the abnormality detection process is executed again after the abnormality is resolved.

  When it is determined in step S202 that the absolute value of the determination index HP is not larger than the main determination value D2, there is a possibility that an abnormality may occur so that the change mode of the determination index HP is monitored in a state where the gas purge is not performed. If not, the process proceeds to step S209. In step S209, the abnormality timer q is cleared to zero.

  Returning to the description of FIG. 3, in the abnormality detection process, when it is determined that the air-fuel ratio feedback control is not executed in step S101, and when it is determined that the actual injection amount is included in the allowable range in step S102. The process proceeds to step S113. In Step S113, assuming that the possibility of occurrence of an abnormality in the combustion system 10 is very low, the temporary abnormality timer p, the main abnormality timer q, and the number-of-times counter u are cleared to zero.

  The ECU 30 has a function of executing each step of the abnormality detection process. The provisional abnormality determination corresponds to a restriction determination unit that determines whether or not the function of executing the processes of steps S106 and S108 restricts the execution of the gas purge, such as whether to stop the gas purge. In particular, the function of executing the process of step S106 corresponds to a regulation value determining unit, and the function of executing the process of step S108 corresponds to a regulation time determining unit. Further, the function of executing the process of step S107 corresponds to a restriction measuring unit, and the function of executing the process of step S110 corresponds to a restriction executing unit that restricts execution of gas purge.

  For this abnormality determination, the function of executing the processes of steps S202, S204, and S207 corresponds to an abnormality determination unit that determines whether an abnormality has occurred. In particular, the function for executing the process of step S202 corresponds to the abnormal value determining unit, and the function for executing the processes of steps S204 and S207 corresponds to the abnormal time determining unit. The function for executing the processes of steps S203 and S205 corresponds to the abnormality measuring unit.

  An abnormality detection process when an abnormality occurs in the combustion system 10 will be described. First, a case where a lean abnormality occurs in which the correction amount HPa and the learning value HPb increase excessively will be described with reference to the time chart of FIG.

  As shown in FIG. 5, when the air purge ratio control is started at the timing t1 in a state where the gas purging is being performed by the purge device 22, the correction amount HPa starts to increase, and accordingly, the determination index HP is also increased. Start to increase. When the absolute value of the determination index HP becomes larger than the temporary determination value D1 at the timing t2, the temporary abnormality process is started and the temporary abnormality timer p starts to increase. After that, at the timing t3 when the continuation time in which the absolute value of the determination index HP is larger than the temporary determination value D1 becomes longer than the temporary determination time Ta, the purge purge request is satisfied, and the gas purge is stopped, and the temporary abnormality timer p is cleared to zero.

  After the timing t3, even if the gas purge is stopped, the abnormality process is not started in a period in which the determination index HP is not larger than the main determination value D2, and the timing t4 when the determination index HP becomes larger than the main determination value D2. This abnormality process is started. Since the state where the absolute value of the determination index HP is larger than the main determination value D2 continues, the increase and reset of the abnormality timer q and the increase of the number counter u are repeated at timings t5 and t6. Then, at the timing t7 when the continuation time in which the absolute value of the determination index HP is larger than the main determination value D2 becomes longer than the main determination time Tb, the determination of lean abnormality is confirmed and abnormality countermeasure processing is performed. After timing t7, the gas purge is held in a stopped state until the abnormality is resolved.

  At timing t7, when the occurrence of abnormality is determined, the abnormality timer q and the number counter u are cleared to zero, and the air-fuel ratio feedback control is stopped. When the air-fuel ratio feedback control is stopped, the correction amount HPa is changed to zero by changing from the correction upper limit value CR1 to the feedback center value CR0, and the learning value HPb is held at the learning upper limit value LR1. Thereby, the determination index HP at the timing t7 becomes a value decreased by the correction upper limit value CR1.

  In FIG. 5, an interval period Tc occurs between the timing t3 when the determination result of the temporary abnormality determination using the temporary determination value D1 is output and the timing t4 when the main abnormality determination using the main determination value D2 is started. ing. As described above, when the gas purge is performed until the determination result of the provisional abnormality determination is obtained, the state in which the detection value of the air-fuel ratio sensor 18 is likely to fluctuate due to the gas purge is easily resolved in the interval period Tc. Become. For this reason, the determination accuracy of this abnormality by this abnormality determination is enhanced by the interval period Tc.

  Next, a case where a rich abnormality occurs in which the correction amount HPa and the learning value HPb are excessively reduced will be described with reference to the time chart of FIG.

  As shown in FIG. 6, when the air-fuel ratio feedback control is started at timing t11 in a state where the gas purge by the purge device 22 is stopped at timing t10, the correction amount HPa starts to decrease, and accordingly. The determination index HP also starts decreasing. Then, at the timing t12, when the absolute value of the determination index HP becomes larger than the temporary determination value D1, the temporary abnormality process is started and the temporary abnormality timer p starts to increase.

  Thereafter, the absolute value of the determination index HP is higher than the final determination value D2 at a timing t13 before the duration time in which the absolute value of the determination index HP is larger than the temporary determination value D1 becomes longer than the temporary determination time Ta. It becomes larger, this abnormality process is started, and this abnormality timer q starts to increase. When the temporary abnormality process is started in a state where the gas purge is not performed, the temporary abnormality process and the main abnormality process may be performed in parallel depending on the degree of increase in the absolute value of the determination index HP.

  Then, at the timing t14 when the absolute value of the determination index HP is longer than the temporary determination value D1, the purge prohibition request is satisfied even when the gas purge is not performed at timing t14. . This prevents the gas purge from being started during the execution of the abnormality process.

  After this, as in FIG. 5, the state where the absolute value of the determination index HP is greater than the main determination value D2 continues, so that the increase and reset of the abnormal timer q and the increase of the main counter u are timed. Repeat for t15 and t16. Then, at the timing t17 when the continuation time in which the absolute value of the determination index HP is larger than the main determination value D2 becomes longer than the main determination time Tb, the determination of rich abnormality is confirmed and abnormality countermeasure processing is performed.

  In FIG. 6, the temporary abnormality determination using the temporary determination value D1 and the main abnormality determination using the main determination value D2 are performed in parallel in the overlap period Td that is a period between the timing t13 and the timing t14. ing. In this case, compared with a configuration in which the temporary abnormality determination and the main abnormality determination are not performed in parallel, in a situation where the gas purge is not performed, it is necessary until the result of the main abnormality determination is obtained after the temporary abnormality determination is started. Time is shortened.

  According to the present embodiment described so far, the determination index HP used for both the temporary abnormality determination and the main abnormality determination includes the correction amount HPa and the learning value HPb used for air-fuel ratio feedback control. For this reason, even if the determination accuracy of the temporary abnormality determination is lower than the determination accuracy of the main abnormality determination, abnormality detection to the extent that an abnormality may have occurred in the combustion system 10 can be performed by the temporary abnormality determination.

  Therefore, as in this embodiment, the provisional abnormality determination used for determining whether or not the purge prohibition request is performed is used as an abnormality determination with low determination accuracy, so that the determination accuracy is high in a state where the gas purge is prohibited. This abnormality determination can be performed anew. In this case, since this abnormality determination is performed with priority over the gas purge, it is possible to suppress the time for performing this abnormality determination from being insufficient and delaying abnormality detection. On the other hand, when the possibility of occurrence of an abnormality is so low that it is denied even in the provisional abnormality determination, the gas purge is prioritized over the abnormality determination. It becomes difficult to run out. In this case, it can be suppressed that the amount of fuel gas adsorbed by the canister exceeds the adsorption limit amount and the fuel gas is unintentionally released from the exhaust system or the purge device 22.

  As described above, since the idle stop is employed, both the time for detecting the abnormality and the time for performing the gas purge are well balanced even in a vehicle in which the engine 11 is in a relatively short operating state. It becomes possible to secure. Therefore, both the abnormality detection related to the engine 11 and the purge of the fuel gas can be properly performed.

  According to the present embodiment, since the determination result of step S106 using the temporary determination value D1 is used for the temporary abnormality determination, it is easy to determine the temporary abnormality determination accuracy by optimizing the value of the temporary determination value D1. Can be adjusted. For example, when the determination index HP changes due to aging deterioration of the air-fuel ratio sensor 18 or the like instead of occurrence of an abnormality or change in use environment, the temporary determination value D1 is set to an appropriate value according to the degree of aging deterioration or environment change. By doing so, the determination accuracy of temporary abnormality can be improved. As a result, it is possible to suppress the occurrence of prohibition of gas purge even though the possibility of occurrence of abnormality is very low, or prohibition of gas purge even though the possibility of occurrence of abnormality is high to some extent. .

  Further, since the determination result of step S108 using the main determination value D2 is used for the main abnormality determination, the determination accuracy of the main abnormality can be easily adjusted by optimizing the main determination value D2. For this reason, as in the case of the temporary abnormality determination using the temporary determination value D1, the determination accuracy of this abnormality is set by setting the determination value D2 to an appropriate value according to the degree of deterioration of the combustion system 10 and the environmental change. Can be increased. As a result, in the state where the gas purge is not performed, the determination of the occurrence of abnormality cannot be determined even though the abnormality has actually occurred, or the abnormality has occurred even though the abnormality has not actually occurred. It can be suppressed that the determination is fixed.

  According to the present embodiment, since the temporary determination value D1 is smaller than the main determination value D2, the main abnormality process of step S112 is started at a timing before the temporary abnormality process of steps S106 to S111 is started. Can be avoided. In this case, since the main abnormality determination is started before the provisional abnormality determination for prohibiting the gas purge, it is possible to suppress the gas purge from being started even though the main abnormality processing is being performed. Therefore, it is possible to avoid that the determination accuracy of the occurrence of abnormality due to the abnormality process is lowered due to the gas purge.

  According to the present embodiment, the provisional determination value D1 is set to an absolute value of a value included in the restriction range CRa in the correction range CR. For this reason, if the correction amount HPa is a value that does not require the change of the learning value HPb, the gas purge is not prohibited because it is not out of the allowable range of the temporary abnormality. In this case, unlike the present embodiment, for example, it is less likely that the gas purge is over-prohibited than the configuration in which the abnormality determination is performed with priority over the gas purge. Can be suppressed.

  On the other hand, the main determination value D2 is set to a value that is not included in the restriction range CRa. In this case, if the correction amount HPa is a value that requires the change of the learning value HPb, the gas purge is prohibited because it is out of the allowable range of the temporary abnormality. In this case, unlike the present embodiment, for example, the number of times that the abnormality determination is performed can be appropriately ensured as compared with the configuration in which the gas purge is performed with priority over the abnormality determination. Can be prevented from being delayed. Therefore, when an abnormality occurs, the abnormality can be detected promptly.

  According to the present embodiment, since the correction amount HPa and the learning value HPb are included in the determination index HP, the temporary abnormality determination and the main abnormality determination can be performed from the viewpoint of both the short term and the long term. For this reason, excessively prohibiting gas purging when the determination index HP is not abnormal due to temporary increase / decrease, or when the determination index HP is not abnormal due to long-term increase / decrease due to deterioration of the combustion system 10 or the like. Or misdetecting the occurrence of an abnormality can be suppressed.

  According to the present embodiment, since the determination result of step S202 using the temporary determination time Ta is used for the temporary abnormality determination, it is easy to determine the temporary abnormality determination accuracy by optimizing the value of the temporary determination time Ta. Can be adjusted. For this reason, by setting the temporary determination time Ta to an appropriate value according to the degree of aging deterioration and environmental change of the combustion system 10, it is possible to improve the determination accuracy for the temporary abnormality determination using the change mode of the determination index HP. it can.

  Further, since the determination result of steps S204 and S207 using the main determination time Tb is used for the main abnormality determination, the determination accuracy of the main abnormality determination can be easily adjusted by optimizing the value of the main determination time Tb. can do. Therefore, similarly to the main abnormality determination using the main determination time Tb, the determination index HP is changed by setting the main determination time Tb to an appropriate value in accordance with the degree of deterioration of the combustion system 10 and the environmental change. The determination accuracy can be improved for the present abnormality determination using the aspect.

  According to the present embodiment, since the temporary determination time Ta is shorter than the main determination time Tb, it is avoided that the main abnormality process of step S112 ends at a timing before the temporary abnormality processing of steps S106 to S111 ends. it can. In this case, because the determination result of the temporary abnormality determination has not yet been issued and the gas purge is not prohibited at the timing when the determination result of the main abnormality determination is obtained, the determination result of the main abnormality determination is being executed. It can be suppressed that the result is obtained.

  According to the present embodiment, when the gas purge is not performed, the temporary abnormality process using the temporary determination value D1 and the main abnormality process using the main determination value D2 can be performed in duplicate and in parallel. It has become. In this case, for example, the time required from the start of the provisional abnormality process to the decision result of the abnormality determination is shortened compared to a configuration in which the provisional abnormality process and the abnormality process are always performed sequentially without overlapping. The time during which the gas purge can be performed can be lengthened. Thereby, it can suppress more reliably that gas purge runs short and fuel gas leaks unintentionally.

(Second Embodiment)
In the second embodiment, in the abnormality process of the abnormality detection process, the abnormality determination is performed on one of the lean and rich air-fuel ratios while the normal determination is performed on the other. In the present embodiment, the difference from the first embodiment will be mainly described.

  The ECU 30 basically performs the same abnormality process as in the first embodiment. As shown in FIG. 7, in step S301, as in step S201 of the first embodiment, it is determined whether or not the gas purge is stopped. When the gas purge is in a stopped state, in this embodiment, in steps S302 to S315, an abnormality occurs in each of the cases where the correction of the air-fuel ratio by the correction amount HPa and the learning value HPb is the lean correction and the rich correction. Or normalization. In the lean correction, the determination index HP is a positive value larger than the feedback initial value IV0 in order to correct the air-fuel ratio to the lean side. In the rich correction, the determination index HP is corrected to correct the air-fuel ratio to the rich side. The negative value is smaller than the feedback initial value IV0.

  In the abnormality process of the first embodiment, the main determination value D2 that is a positive value is used for both the lean correction and the rich correction. On the other hand, in the present abnormality process of the present embodiment, the lean main determination value D2a that is a positive value is used for lean correction, while the rich main determination value D2b that is a negative value is used for rich correction. The absolute value of the rich main determination value D2b is the same value as the lean main determination value D2a, and this is because the standard indicating whether the determination index HP for the main abnormality determination is abnormal is the same for the lean correction and the rich correction. It is shown that. Note that the absolute value of the rich main determination value D2b and the lean main determination value D2a may be set to different values.

  In steps S302 to S311, a lean process for lean correction is performed. In the lean process, in step S302, it is determined whether or not the determination index HP is larger than the lean final determination value D2a. As described above, in the present embodiment, the determination target with the lean final determination value D2a is not the absolute value of the determination index HP but merely a determination index that can be both a positive value and a negative value. When the determination index HP is larger than the lean final determination value D2a, the processing of steps S303 to S307 is performed on the assumption that there is a high possibility of occurrence of abnormality in the lean correction.

  In steps S303 to S307, it is basically determined in the same manner as steps S203 to S207 in the first embodiment whether or not the change mode of the determination index HP is out of the allowable range for lean correction. Here, the abnormality timer q of the first embodiment is replaced with a lean abnormality timer qa because the correction of the air-fuel ratio is lean correction. Also, the main continuation determination value N2 is replaced with a lean abnormality continuation value N2a, the main counter u is replaced with a lean counter ua, and the main abnormality determination number N3 is replaced with a lean determination number N3a. The lean determination time Tb1 is changed.

  In addition, each determination of step S302, S304, S307 can be collectively called a lean abnormality determination. Further, when a state where the determination index HP is larger than the lean final determination value D2a is referred to as a lean determination state, the lean determination state corresponds to the main determination state and the abnormality determination state. Further, the lean final determination value D2a corresponds to the abnormality determination value, and the lean determination time Tb1 corresponds to the abnormality determination time.

  When the determination of lean abnormality is confirmed in step S307, the process proceeds to step S308, and abnormality countermeasure processing is performed as in step S208 of the first embodiment. Here, the process which notifies that the abnormality which generate | occur | produced in the combustion system 10 is a lean abnormality is performed. Further, the lean abnormality timer qa and the lean number counter ua are cleared to zero.

  If the determination index HP is not greater than the lean final determination value D2a in step S302, it is determined that at least a lean abnormality has not occurred, and the process proceeds to step S309. In step S309, the lean normal timer qx indicating that no lean abnormality has occurred is incremented. The lean normal timer qx is set in the storage unit 30b or the like. Here, the duration in which the lean correction is within the allowable range is measured. If the lean correction is normal, NO is determined in step S304 because the lean abnormality timer qa is not added, and the process proceeds to step S310.

  In step S310, it is determined whether the lean normal timer qx is greater than a predetermined lean normal continuation value N2x. A state in which the determination index HP is not greater than the lean main determination value D2a is referred to as a lean normal state. Here, the duration during which the determination index HP is in the lean normal state is a predetermined lean normal determination time Tx (see FIG. 9). ) Judge whether or not it has become longer. The lean normality determination time Tx is set to be shorter than the lean determination time Tb1.

  If the lean normal timer qx is larger than the lean normal continuation value N2x, it is determined that the duration of the lean normal state is longer than the lean normal determination time Tx, and the process proceeds to step S311 to perform the lean normal processing. In the lean normal process, a process for notifying that the lean correction is normal and a process for clearing the lean normal timer qx to zero are performed.

  In step S312, rich processing is performed to determine whether the rich correction is abnormal or not. The rich process will be described with reference to the flowchart of FIG. The rich process is basically the same process as the lean process except that it is lean or rich. Steps S401 to S410 in the rich process correspond to steps S302 to S311 in the lean process.

  In FIG. 8, in step S401, it is determined whether the determination index HP is smaller than the rich main determination value D2b. If the determination index HP is smaller than the rich main determination value D2b, the processing of steps S402 to S406 is performed assuming that the possibility of occurrence of abnormality is high in the rich correction. In steps S402 to S406, whether or not the change mode of the determination index HP is out of the allowable range of rich correction is basically performed in the same manner as steps S303 to S307 of the lean process. Here, the lean abnormality timer qa of the lean process is replaced with the rich abnormality timer qb due to the rich correction of the air-fuel ratio. In addition, the lean abnormality continuation value N2a is replaced with the rich abnormality continuation value N2b, the lean number counter ua is replaced with the rich number counter ub, and the lean determination number N3a is replaced with the rich determination number N3b. The determination time is changed to Tb2. The rich determination time Tb2 is set to the same length as the lean determination time Tb1.

  In addition, each determination of step S401, S403, S406 can be collectively called rich abnormality determination. Further, when a state where the determination index HP is smaller than the rich main determination value D2b is referred to as a rich determination state, the rich determination state corresponds to the main determination state and the abnormality determination state. Further, the rich main determination value D2b corresponds to the abnormality determination value, and the rich determination time Tb2 corresponds to the abnormality determination time.

  When the determination of rich abnormality is confirmed in step S406, the process proceeds to step S407, and the rich abnormality countermeasure process is performed in the same manner as the lean abnormality countermeasure process, except that lean or rich is different. Here, a process for notifying that the abnormality occurring in the combustion system 10 is a rich abnormality is performed. Further, the rich abnormality timer qb and the rich number counter ub are cleared to zero.

  If the determination index HP is not smaller than the rich main determination value D2b in step S401, it is determined that no rich abnormality has occurred and the process proceeds to step S408. In step S408, the rich normal timer qy indicating that no rich abnormality has occurred is incremented. The rich normal timer qy is set in the storage unit 30b or the like. Here, the duration in which the rich correction is within the allowable range is measured. If the rich correction is normal, NO is determined in step S403 because the rich abnormality timer qb is not added, and the process proceeds to step S409.

  In step S409, it is determined whether or not the rich normal timer qy is greater than a predetermined rich normal continuation value N2y. A state where the determination index HP is not smaller than the rich main determination value D2b is referred to as a rich normal state. Here, a duration time during which the determination index HP is in the rich normal state is a predetermined rich normal determination time Ty (see FIG. 10). ) Judge whether or not it has become longer. The rich normal determination time Ty is set to be shorter than the rich determination time Tb2.

  When the rich normal timer qy is larger than the rich normal continuation value N2y, it is determined that the rich correction is normal, and the process proceeds to step S410 to perform rich normal processing. In the rich normal process, a process for notifying that the rich correction is normal and a process for clearing the rich normal timer qy to zero are performed.

  Returning to the description of FIG. 7, after the rich process is completed in step S <b> 312, it is determined whether the lean correction is normal in step S <b> 313, and whether the rich correction is normal is determined in step S <b> 314. To do. If both the lean correction and the rich correction are normal, the process proceeds to step S315, and normal processing is performed to indicate that the air-fuel ratio correction is normal. In the normal processing, processing for permitting the start and continuation of air-fuel ratio feedback control is performed.

  If it is determined in step S302 that the absolute value of the determination index HP is not greater than the main determination value D2, the process proceeds to step S316, and the lean abnormality timer qa, the rich abnormality timer qb, the lean normal timer qx, and the rich normal timer qy are set. Clear to zero. In the present embodiment, as in the first embodiment, various flags and counters are cleared to zero in step S113 of the abnormality detection process. Specifically, in step S113, the lean abnormality timer qa, the rich abnormality timer qb, the lean normal timer qx, the rich normal timer qy, the lean number counter ua, and the rich number counter ub are cleared to zero.

  For the main abnormality determination of the present embodiment, the function for executing the processes of steps S302, S304, S307, S401, S403, and S406 corresponds to the abnormality determination unit. In particular, the function for executing the processes of steps S302 and 401 corresponds to the abnormal value determining unit, and the function for executing the processes of steps S304, S307, S403, and S406 corresponds to the abnormal time determining unit. Further, the function of executing the processes of steps S303, S305, S402, and S404 corresponds to the abnormality measuring unit.

  In the present embodiment, for the temporary determination process, the temporary determination value D1 is the same value as the correction upper limit value CR1. Here, due to the fact that the absolute value of the correction upper limit value CR1 and the correction lower limit value CR2 are the same value, the provisional determination value D1 is the same value as the absolute value of the correction lower limit value CR2.

  Next, the abnormality detection process when the air-fuel ratio correction by the air-fuel ratio feedback control is the lean correction will be described with reference to the time chart of FIG.

  As shown in FIG. 9, at the timing t21, the determination index HP starts to increase with the start of the air-fuel ratio feedback control. However, since this determination index HP is not larger than the lean main determination value D2a, it is assumed that lean is normal. The normal timer qx also starts to increase. When the lean normal timer qx becomes larger than the lean normal continuation value N2x at timing t22, the lean normal determination is established, while the lean normal timer qx is reset to zero by the lean normal processing.

  Thereafter, at timings t23 to t28, the determination index HP, the lean abnormality timer qa, the lean number counter ua, etc. increase or decrease basically in the same manner as the timings t2 to t7 of the first embodiment. In the present embodiment, as described above, since the temporary determination value D1 is the same value as the correction upper limit value CR1, the correction amount HPa is set to the correction upper limit at the timing t23 when the determination index HP is larger than the temporary determination value D1. The learning value HPb starts to increase by reaching the value CR1. Further, at the timing t28, the lean abnormality is established, so that the normal lean condition is not established.

  Next, the abnormality detection process when the air-fuel ratio correction is rich correction will be described with reference to the time chart of FIG.

  As shown in FIG. 10, at the timing t31, the determination index starts to increase with the start of the air-fuel ratio feedback control. However, since this determination index is not smaller than the rich main determination value D2b, the rich normal timer is assumed to be rich normal. qy also begins to increase. When the rich normal timer qy becomes larger than the rich normal continuation value N2y at timing t32, the rich normal timer is determined to be normal while the rich normal timer qy is reset to zero by the rich normal processing.

  Thereafter, at timings t33 to t38, although there is a difference between lean and rich, the determination index HP, the rich abnormality timer qb, the rich number counter ub, and the like increase or decrease basically like timings t23 to t28 in FIG. In particular, at timing t38, rich abnormality is established, so that rich normal is shifted to failure.

  According to the present embodiment, the lean actual determination value D2a and the rich actual determination value D2b are individually set for the lean side and the rich side for the correction of the air-fuel ratio. In this case, the presence or absence of abnormality can be determined for each of the lean side and the rich side by simply comparing the determination index HP with the lean main determination value D2a and the rich main determination value D2b. As described above, the state of the abnormality occurring in the combustion system 10 can be grasped in detail. In addition, since it is individually determined whether or not the correction is normal for each of the lean side and the rich side, the situation of the combustion system 10 can be grasped in detail for both normal and abnormal.

(Other embodiments)
Although a plurality of embodiments according to the present disclosure have been described above, the present disclosure is not construed as being limited to the above embodiments, and can be applied to various embodiments and combinations without departing from the gist of the present disclosure. can do.

  As a modified example 1, in each of the above-described embodiments, after the determination result of the temporary abnormality determination using the temporary determination value D1 or the like is obtained, the main abnormality determination using the main determination value D2 or the like is performed. Also good. In this case, it is avoided that the determination result of the main abnormality determination is obtained before the determination result of the temporary abnormality determination is obtained. For this reason, the degree of freedom in setting the regulation judgment value such as the provisional judgment value D1, the abnormality judgment value such as the main judgment value D2, the regulation judgment time such as the provisional judgment time Ta, and the abnormality judgment time such as the main judgment time Tb. Can be increased. For example, it is possible to adopt a configuration in which the time required for the abnormality detection process is managed by making the abnormality determination time shorter than the regulation determination time.

  As a second modification, in each of the above embodiments, the ECU 30 as the abnormality detection device and the control device may be mounted on the hybrid vehicle. For example, in a hybrid vehicle, when an internal combustion engine such as an engine is in an operating state and air-fuel ratio feedback control is performed, a correction amount, a learning value, or the like is used as a correction parameter, so that a temporary abnormality determination or a main abnormality Assume that the determination is performed.

  As a modified example 3, in the temporary abnormality determination and the main abnormality determination of each of the above embodiments, a restriction determination value such as the temporary determination value D1 and an abnormality determination value such as the main determination value D2 may be variably set. For example, the restriction determination value and the abnormality determination value are variably set according to the external environment of the vehicle, the travel distance, and the like. According to this configuration, since the accuracy of the determination using the restriction determination value is improved, the prohibition and permission of the gas purge can be performed with a good balance. Moreover, since the accuracy of the determination using the abnormality determination value is improved, the abnormality that has occurred can be detected quickly.

  As a modified example 4, in the temporary abnormality determination and the main abnormality determination of each of the above embodiments, determination is not performed using both the size and the change mode of the determination index HP, but only one of the size and the change mode. The determination may be made using. For example, in the temporary abnormality determination of the first embodiment, when the absolute value of the determination index HP is in a temporary determination state larger than the temporary determination value D1, the determination of the temporary abnormality is confirmed regardless of the duration of the temporary determination state. To be configured. Further, even if the absolute value of the determination index HP is not greater than the temporary determination value D1, if the degree of increase or decrease of the determination index HP is out of the allowable range, the determination of temporary abnormality is confirmed. Also good. In any configuration, by using the determination index HP as a correction parameter, it is possible to appropriately determine whether to prohibit gas purge.

  As a modified example 5, regarding the provisional abnormality determination of each of the above embodiments, each of the lean correction and the rich correction is individually performed in the same manner as the lean main determination value D2a and the rich main determination value D2b of the main abnormality determination of the second embodiment. A provisional determination value may be set. For example, a lean provisional determination value that is a positive value and a rich provisional determination value that is a negative value are set. In this configuration, in the provisional abnormality determination, it is possible to grasp which of the lean correction and the rich correction determines the provisional abnormality determination.

  As a modified example 6, the total value of the correction amount HPa and the learning value HPb may not be used as the correction parameter in each of the above embodiments, but one of the correction amount HPa and the learning value HPb may be used. In the air-fuel ratio feedback control, in addition to the feedback amount, a deviation or a detected value of the air-fuel ratio sensor 18 may be used as a correction parameter. Even in these cases, the correction parameter indicates the correction mode of the air-fuel ratio. Note that the reference for the correction amount HPa and the learning value HPb may not be the feedback initial value IV0 but may be zero of the air-fuel ratio.

  As a modified example 7, the air-fuel ratio in each of the above embodiments may be corrected by control such as feedforward control different from feedback control. Even in this configuration, the correction parameter including the correction amount and the learning value is used for the temporary abnormality determination as the restriction determination and the main abnormality determination as the abnormality determination, so that both the abnormality detection and the gas purge can be appropriately performed.

  As a modified example 8, in each of the above embodiments, an abnormality determination using an abnormality determination value such as the determination value D2 may be performed in a state where gas purge is not prohibited. For example, when the supply amount of fuel gas from the purge device 22 to the intake passage 12 is smaller than a predetermined reference amount, an abnormality determination using the abnormality determination value is performed. As in this configuration, if the supply amount of fuel gas by gas purge is less than the reference amount, it is possible to optimize the determination accuracy of abnormality determination using the abnormality determination value even if gas purge is not prohibited.

  For example, in the first embodiment, in step S201, it is determined whether or not the gas purge is regulated by determining whether or not the supply amount of the fuel gas by the gas purge is smaller than the reference amount, and the gas purge is regulated. If yes, the process proceeds to step S202. In step S110, not a purge prohibition request, but a purge regulation request for regulating gas purge by making the supply amount of fuel gas by gas purge smaller than a reference amount.

  As a modified example 9, in each of the above-described embodiments, the configuration that functions as the abnormality detection device and the control device may be various arithmetic devices mounted on the vehicle instead of the ECU 30, and a plurality of arithmetic devices may be included. You may exhibit the function as a control apparatus by cooperation. Various programs may be stored in a non-transitional tangible storage medium such as a flash memory or a hard disk provided in each arithmetic device.

  DESCRIPTION OF SYMBOLS 10 ... Combustion system, 11 ... Engine as internal combustion engine, 30 ... ECU as abnormality detection device and control device, CRa ... Limit range, D1 ... Temporary judgment value as regulation judgment value, D2 ... Main judgment as abnormality judgment value Value, D2a: Lean determination value as an abnormality determination value, D2b: Rich determination value as an abnormality determination value, HP: Determination index as a correction parameter, HPa: Correction amount, HPb: Learning value, Ta: Regulation determination time Temporary determination time, Tb ... main determination time as abnormality determination time, Tb1 ... lean determination time as abnormality determination time, Tb2 ... rich determination time as abnormality determination time, S106 ... regulation determination unit and restriction value determination unit, S107 ... Regulation measuring unit, S108 ... regulation determination unit and regulation time judgment unit, S110 ... regulation execution unit, S202 ... abnormality judgment unit and abnormal value judgment unit, S203 S205: Abnormal measurement unit, S204, S207 ... Abnormality determination unit and abnormal time determination unit, S302 ... Abnormality determination unit and abnormal value determination unit, S303, S305 ... Abnormality measurement unit, S304, S307 ... Abnormality determination unit and abnormal time determination unit , S401 ... abnormality determination unit and abnormal value determination unit, S402, S404 ... abnormality measurement unit, S403, S406 ... abnormality determination unit and abnormality time determination unit.

Claims (9)

An abnormality detection device (30) for detecting an abnormality in a combustion system (10) having an internal combustion engine (11) for burning fuel,
Based on a correction parameter (HP) indicating a correction mode of the air-fuel ratio in the air-fuel ratio control for controlling the air-fuel ratio of the exhaust discharged from the internal combustion engine, a fuel gas that is a gas obtained by evaporating the fuel is supplied to the internal combustion engine. A restriction determination unit (S106, S108) for determining whether or not to restrict the gas purge to be supplied;
An abnormality determination unit (S202) that determines whether an abnormality has occurred in the combustion system based on the correction parameter when the restriction determination unit determines to restrict the gas purge and the gas purge is in a stopped state. , S204, S207, S302, S304, S307, S401, S403, S406),
An abnormality detection device comprising: The restriction determination unit
A restriction value determination unit (S106) for determining whether or not the absolute value of the correction parameter is larger than a predetermined restriction determination value (D1), and whether or not the gas purge is restricted is determined as the restriction value. Determine based on the determination result of the determination unit,
The abnormality determination unit
An abnormal value determination unit (S202, S302, S401) for determining whether or not the absolute value of the correction parameter is larger than a predetermined abnormality determination value (D2, D2a, D2b); The abnormality detection device according to claim 1, wherein whether or not an abnormality has occurred is determined based on a determination result of the abnormal value determination unit.   The abnormality detection device according to claim 2, wherein an absolute value of the restriction determination value is smaller than an absolute value of the abnormality determination value. For the correction parameter, a limit range (CRa) that is a range for limiting the correction of the air-fuel ratio is set,
The restriction determination value is set to a value included in the limit range,
The abnormality detection device according to claim 2 or 3, wherein the abnormality determination value is set to a value not included in the limit range. The correction parameter is
A correction amount (HPa) set in the limit range;
A learning value (HPb) corrected by changing the limit range;
The abnormality detection device according to claim 4, comprising: The restriction determination unit
A regulation time determination unit (S108) for determining whether or not the duration of the correction parameter in a predetermined regulation determination state has reached a predetermined regulation determination time (Ta); Is determined based on the determination result of the restriction time determination unit,
The abnormality determination unit
An abnormal time determination unit (S204, S207, S304, and S304) that determines whether or not the duration of the correction parameter in a predetermined abnormality determination state has reached a predetermined abnormality determination time (Tb, Tb1, Tb2). S307, S403, S406) and determining whether an abnormality has occurred in the combustion system based on a determination result of the abnormal time determination unit. Anomaly detection device.   The abnormality detection device according to claim 6, wherein the restriction determination time is shorter than the abnormality determination time. A regulation measuring unit (S107) for measuring a duration time during which the correction parameter is in the regulation judgment state;
When the gas purge is in a restricted state and the correction parameter is in the abnormality determination state, an abnormality that measures the duration of the abnormality determination state overlapped with the measurement of the duration of the restriction determination state by the restriction measurement unit A measurement unit (S203, S205, S303, S305, S402, S404);
The abnormality detection device according to claim 6, comprising: A control device (30) for controlling the operation of a combustion system (10) having an internal combustion engine (11) for burning fuel,
Based on a correction parameter (HP) indicating a correction mode of the air-fuel ratio in the air-fuel ratio control for controlling the air-fuel ratio of the exhaust discharged from the internal combustion engine, a fuel gas that is a gas evaporated from the fuel is supplied to the internal combustion engine A restriction determination unit (S106, S108) for determining whether or not to restrict the gas purge to be supplied;
A regulation execution unit (S110) that regulates the gas purge when the regulation judgment unit determines to regulate the gas purge;
An abnormality determination unit (S202, S204, S207, S302) that determines whether an abnormality has occurred in the combustion system based on the correction parameter when execution of the gas purge is restricted by the restriction execution unit. , S304, S307, S401, S403, S406),
A control device for a combustion system.

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