JP3985098B2 - Engine control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to prevention of clogging of a particulate filter that collects exhaust particulates contained in engine exhaust gas, and belongs to the technical field of engine control devices.
[0002]
[Prior art]
In general, exhaust gas of a diesel engine contains particulates called particulates, and a particulate filter that collects and removes the particulates may be provided in the exhaust passage.
[0003]
In such a filter, as the engine operating time increases, the amount of exhaust particulates collected and accumulated in the filter increases. As a result, the filter gradually becomes clogged. When established, the exhaust particulates in the filter are removed, that is, the filter is regenerated.
[0004]
In order to determine whether or not this predetermined condition is satisfied, a pressure sensor or the like for detecting the exhaust pressure is provided on the input side and output side of the filter, and the trapping is performed based on the differential pressure detected by both pressure sensors. The amount of exhaust particulate that is collected and accumulated may be detected. In order to improve the detection accuracy, a temperature sensor that detects the temperature of the filter may be provided, and the calculated exhaust particulate amount may be corrected according to the detected temperature.
[0005]
By the way, when these sensors fail, it becomes impossible to detect the amount of exhaust particulates collected and accumulated in the filter with high accuracy, and this impedes regeneration control of the particulate filter based on this. As a result, the filter may be clogged, the filter may break down due to abnormal combustion associated with the clogging, and the filter may be melted.
[0006]
In order to deal with such sensor failure, for example, when a differential pressure sensor for judging the regeneration time fails, the judgment of the regeneration time is made on the basis of the accumulated engine speed and interval time from the end of the previous regeneration. (For example, refer to Patent Document 1).
[0007]
[Patent Document 1]
JP-A-6-280544
[0008]
[Problems to be solved by the invention]
However, in the technique described in Patent Document 1, even if the same integrated rotational speed is used, for example, in an engine operating state in which the amount of EGR, that is, the amount of exhaust gas recirculated from the exhaust system to the intake system increases, EGR Since there is a tendency to increase the exhaust particulate emitted from the engine body rather than the engine operating state with a small amount, it is not possible to accurately determine the regeneration time, in other words, to accurately determine clogging of the filter, Problems such as filter failure cannot be reliably prevented.
[0009]
Therefore, the present invention provides an engine that can prevent clogging of the filter and abnormal combustion associated therewith even when an abnormality occurs in a sensor that detects the amount of exhaust particulate trapped in the particulate filter. It is an object to provide a control device.
[0010]
[Means for Solving the Problems]
  That is, the invention described in claim 1
  Parameter value detection means for detecting a parameter value related to the collection amount of exhaust particulates collected in the collection means provided in the exhaust passage of the engine;
  TheBased on the parameter value detected by the parameter value detection meansthe aboveCollection amount estimation means for estimating the amount of exhaust particulates collected by the collection means;
  TheThe collection amount estimated by the collection amount estimation means is predetermined.FirstDetermining whether or not the amount is overFirstCollection amount determination means;
  The firstThe collected amount is determined by the collected amount judging means.The firstWhen it is determined that the amount exceeds the specified level,the aboveA control device for an engine provided with a regeneration means for regenerating the collection means by burning and removing exhaust particulates collected by the collection means,
  A collected amount storage means for storing the collected amount estimated by the collected amount estimating means;
  An abnormality detecting means for detecting an abnormality of the parameter value detecting means;,
  When the abnormality of the parameter value detection means is detected by the abnormality detection means, the second collection for determining whether or not the collection amount stored in the collection amount storage means immediately before the abnormality detection is equal to or greater than a second predetermined amount A quantity determination means;
  When the collected amount determining means determines that the collected amount is equal to or greater than the second predetermined amount, the operation period of the regenerating means is set according to the collected amount stored in the collected amount storage means immediately before the abnormality is detected. Playback period setting means to set,
  the aboveWhen an abnormality of the parameter value detection means is detected by the abnormality detection means,
Compared to when no abnormality is detected,To prevent the exhaust particles from clogging the collection meansControl engine operating conditionsIn addition, when an abnormality is detected in the parameter value detecting means, the collected amount stored in the collected amount storage means immediately before the abnormality is detected by the second collected amount determining means is determined to be greater than or equal to a second predetermined amount. When the regeneration means is operated, the regeneration means performs the control for suppressing the clogging of the collection means after the regeneration of the collection means during the operation period set by the regeneration period setting means.And clogging suppression means.
[0011]
  According to this invention, when the abnormality of the parameter value detection means is detected by the abnormality detection means, the engine operating state is controlled and the exhaust particulates are clogged in the collection means, compared to when no abnormality is detected. Therefore, clogging of the collecting means when the parameter value detecting means is abnormal, and failure of the collecting means due to abnormal combustion associated therewith are prevented.In particular, when an abnormality of the parameter value detection means is detected by the abnormality detection means, it is determined whether or not the collected amount stored in the collected amount storage means immediately before the abnormality detection is equal to or greater than a second predetermined amount. When it is determined that the collected amount is equal to or greater than the second predetermined amount, the regeneration unit performs regeneration of the collection unit during the operation period set by the regeneration period setting unit to reduce the collected amount of exhaust particulates. In addition, since control to suppress clogging is performed, clogging when the amount of trapped material is large and abnormal combustion associated therewith are reliably prevented.
[0012]
  According to a second aspect of the present invention, in the first aspect of the invention, the clogging suppressing means is configured such that when the abnormality detecting means detects an abnormality of the parameter value detecting means, no abnormality is detected. Compared to the above, the exhaust gas recirculation means that recirculates the exhaust gas to the intake side according to the operating state of the engine is controlled to reduce the recirculation amount of the exhaust gas to the intake side.controlAnd the fuel injection control means for controlling the fuel injection timing to advance the injection timingcontrolIt is characterized by performing at least one of the following.
[0013]
  According to the present invention, when the abnormality of the parameter value detection means is detected by the abnormality detection means, the exhaust gas recirculation amount to the intake side is controlled by controlling the exhaust gas recirculation means compared to when no abnormality is detected. DecreasecontrolAnd the fuel injection control means for controlling the fuel injection timing to advance the injection timingcontrolAt least one of the above is performed.
[0014]
That is, if the exhaust gas recirculation means is controlled to reduce the recirculation amount of the exhaust gas to the intake side, the exhaust amount of exhaust particulate discharged from the combustion chamber is suppressed, resulting in clogging and accompanying this. Abnormal combustion is prevented. Further, if the fuel injection control means for controlling the fuel injection timing is controlled to advance the injection timing, the amount of NO2 discharged from the combustion chamber is increased and combustion of exhaust particulates by the collection means is promoted. As a result, clogging and accompanying abnormal combustion are prevented. Moreover, if both of these are implemented, these will be prevented more effectively.
[0017]
  further,Claim 3The invention described inBased on the parameter value detecting means for detecting the parameter value related to the collection amount of the exhaust particulate collected in the collecting means provided in the exhaust passage of the engine, and the parameter value detected by the parameter value detecting means A collection amount estimation means for estimating the amount of exhaust particulates collected by the collection means, and whether or not the collection amount estimated by the collection amount estimation means is equal to or greater than a predetermined first predetermined amount. When the collected amount is determined to be greater than or equal to the first predetermined amount by the first collected amount judging means and the first collected amount judging means, the exhaust particulates collected by the collecting means are An engine control device provided with a regeneration means for regenerating the collection means by burning off, an abnormality detection means for detecting an abnormality of the parameter value detection means, and a parameter value detection means of the parameter value detection means by the abnormality detection means. When an abnormality is detected Compared to when no abnormality is detected, control to control the exhaust gas recirculation means for recirculating the exhaust gas to the intake side according to the operating state of the engine to reduce the recirculation amount of the exhaust gas to the intake side, Clogging suppression means for suppressing clogging of exhaust particulates in the collection means by performing at least one of control for controlling the fuel injection control means for controlling the fuel injection timing to advance the injection timing; andCollected amount storage means for storing the collected amount estimated by the collected amount estimation means;the aboveWhen an abnormality of the parameter value detection means is detected by the abnormality detection means, immediately before the abnormality detectionthe aboveA second collected amount determination means for determining whether or not the collected amount stored in the collected amount storage means is greater than or equal to a predetermined second predetermined amount;And the aboveThe clogging suppression means isthe aboveWhen the collected amount is determined to be greater than or equal to the second predetermined amount by the second collected amount determination means, the exhaust gas recirculation means is controlled to reduce the exhaust gas recirculation amount to the intake side.controlAnd advance the injection timing by controlling the fuel injection control meanscontrolDo boththe aboveWhen the second collection amount determination means determines that the collection amount is not equal to or greater than the second predetermined amount, the exhaust gas recirculation means is controlled to reduce the exhaust gas recirculation amount.controlOnly to do.
[0018]
According to this invention, when the abnormality of the parameter value detection means is detected by the abnormality detection means, when the collection amount immediately before the occurrence of the abnormality is determined not to be greater than or equal to the second predetermined amount by the second collection amount determination means. Since the exhaust gas recirculation means is controlled to reduce the recirculation amount of the exhaust gas, clogging of the collection means and abnormal combustion associated therewith are reliably prevented, and the injection timing is advanced. Since this is not performed, noise that tends to occur is prevented by advancing the injection timing.
[0019]
On the other hand, when the abnormality detection unit detects an abnormality in the parameter value detection unit, the exhaust gas recirculation occurs when the second collection amount determination unit determines that the collection amount immediately before the occurrence of the abnormality is equal to or greater than the second predetermined amount. Both the control of the means to reduce the recirculation amount of the exhaust gas to the intake side and the control of the fuel injection control means for controlling the fuel injection timing to advance the injection timing. As compared with the case where only this is performed, clogging of the collecting means and abnormal combustion associated therewith are surely prevented.
[0022]
  Also,Claim 4The invention described inBased on the parameter value detecting means for detecting the parameter value related to the collection amount of the exhaust particulate collected in the collecting means provided in the exhaust passage of the engine, and the parameter value detected by the parameter value detecting means A collection amount estimation means for estimating the amount of exhaust particulates collected by the collection means, and whether or not the collection amount estimated by the collection amount estimation means is equal to or greater than a predetermined first predetermined amount. When the collected amount is determined to be greater than or equal to the first predetermined amount by the first collected amount judging means and the first collected amount judging means, the exhaust particulates collected by the collecting means are An engine control device provided with a regeneration means for regenerating the collection means by burning off, an abnormality detection means for detecting an abnormality of the parameter value detection means, and exhaust gas according to the operating state of the engine Exhaust gas return returning to the intake side A plurality of clogging suppression execution means including at least an exhaust gas recirculation amount reduction means for controlling the means to reduce the exhaust gas recirculation amount, and when the abnormality detection means detects an abnormality in the parameter value detection means, By operating the exhaust gas recirculation amount reducing means in preference to other clogging suppression executing means, the clogging suppressing means for suppressing clogging of the exhaust particulates into the collecting means, and the aboveCollected amount storage means for storing the collected amount estimated by the collected amount estimation means;the aboveWhen an abnormality of the parameter value detection means is detected by the abnormality detection means, immediately before the abnormality detectionthe aboveA second collected amount determination means for determining whether or not the collected amount stored in the collected amount storage means is greater than or equal to a predetermined second predetermined amount;And the aboveThe clogging suppression means isthe aboveWhen the collected amount is determined to be greater than or equal to the second predetermined amount by the second collected amount determining means, the exhaust gas recirculation amount reducing means is activated and the other clogging suppression executing means is activated.
[0023]
  According to this invention,In the case where the abnormality of the parameter value detection means is detected by the abnormality detection means, the clogging is suppressed when it is determined that the collected amount stored in the collected amount storage means immediately before the abnormality detection is equal to or more than the second predetermined amount. As a control toBy operating not only the exhaust gas recirculation amount reducing means but also other clogging suppression executing means, clogging of the collecting means is strongly suppressed.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0030]
The present invention is applied to a diesel engine 1 shown in FIG. The engine 1 is a four-cylinder engine, for example, and includes four pistons 3 that move up and down in the cylinder bore of the engine body 2 (only one is shown in FIG. 1). The cylinder head of the engine body 2 is provided with an injector 4 for each cylinder, and the injector 4 directly injects fuel into the in-cylinder combustion chamber.
[0031]
A high-pressure fuel pump 5 and a common rail 6 are arranged on a fuel supply path between the fuel tank and the injector 4 (not shown). The pump 5 pumps fuel from the fuel tank to the common rail 6, and the common rail 6 accumulates the pumped fuel. When the injector 4 is opened, the fuel accumulated in the common rail 6 is injected at a high pressure from the injection port of the injector 4. At this time, the fuel injection amount can be controlled by controlling the valve opening time of the injector 4 and the fuel pressure in the common rail 6. Further, the fuel injection timing can be controlled by controlling the valve opening timing of the injector 4. In the figure, arrows on the fuel supply path indicate the flow of fuel.
[0032]
In the intake passage 10, an air cleaner 11, an air flow meter 12, a turbocharger compressor 13, an intercooler 14, a throttle valve 15 that adjusts the intake air amount, and a throttle valve that detects the opening of the throttle valve 15 in order from the upstream side. An opening sensor 16, an intake air temperature sensor 17, an intake pressure sensor 18, and an intake valve 19 are provided.
[0033]
In the exhaust passage 20, in order from the upstream side, an exhaust valve 21, a turbocharger turbine 22, a first exhaust temperature sensor 23, an oxidation catalyst device 24, a second exhaust temperature sensor 25, an upstream pressure sensor 26, and in exhaust gas The particulate filter 27 for collecting the exhaust particulates, the downstream pressure sensor 28, and the third exhaust temperature sensor 29 are provided. Further, an EGR passage 30 is disposed between a relatively upstream portion of the exhaust passage 20 and a relatively downstream portion of the intake passage 10, and an EGR valve 31 for adjusting the exhaust gas recirculation amount is provided on the passage 30. . The filter 27 is coated with an oxidation catalyst substance containing a noble metal such as platinum.
[0034]
An engine speed sensor 41 is provided in the crankcase of the engine body 2, and a water temperature sensor 42 is provided in the cylinder block. The common rail 6 is provided with a common rail pressure sensor 43 that detects fuel pressure accumulation. An accelerator opening sensor 45 that detects the amount of depression of the accelerator pedal 44 is provided in the passenger compartment.
[0035]
The control unit 50 of the engine 1 exits from the filter 27, the intake air amount detected by the sensors, the intake air temperature, the intake pressure, the exhaust gas temperature flowing into the oxidation catalyst device 24, the exhaust gas temperature flowing into the particulate filter 27, and the filter 27. A control signal is output to the injector 4 and the high-pressure fuel pump 5 based on the exhaust temperature afterwards, the upstream and downstream pressures across the filter 27, the engine speed, the coolant temperature, the fuel pressure in the common rail 6, the engine load, etc. To do.
[0036]
The control unit 50 corrects the basic fuel injection amount determined in consideration of EGR and the like from the engine speed by the engine speed sensor 41 and the engine load by the accelerator opening sensor 45 by the coolant temperature, the intake air temperature, etc. Calculate the amount.
[0037]
The control unit 50 controls the EGR valve 31 and the intake throttle valve 15 to control the EGR amount. As shown in the map of FIG. 2, the EGR amount is decreased as the engine load (accelerator opening) is increased and as the engine speed is increased.
[0038]
The control unit 50 collects the particulate filter 27 by comparing the pressure difference between the upstream and downstream pressures sandwiching the filter 27 and the temperature detected by the second exhaust temperature sensor 25 with the map shown in FIG. Estimate the amount of exhaust particulate. According to this, the estimated collection amount becomes larger as the differential pressure is larger. Further, when the detected temperature is higher than the predetermined standard temperature, the pressure loss in the filter is reduced. Therefore, the characteristics for high temperature that uses a larger collection amount than the standard temperature are used even with the same differential pressure value. On the contrary, when the detected temperature is lower than the predetermined standard temperature, the pressure loss in the filter increases. Therefore, the characteristics for low temperature, which is smaller than the standard temperature even with the same differential pressure value, are used. . This is merely an example, and more detailed characteristics may be provided for each temperature, or the standard characteristics may be multiplied by a correction coefficient according to the temperature.
[0039]
The control unit 50 executes the combustion removal of the exhaust particulates collected by the filter 27, that is, the regeneration of the filter 27, when the estimated collection amount becomes a predetermined amount or more. That is, the opening degree of the intake throttle valve 15 is changed to a smaller opening degree than that at the time of non-regeneration (changed to the closed side), and after the main injection in the vicinity of the compression top dead center of the piston 3, the fuel is supplied during the expansion stroke. Additional injection (post injection) is started. In this post-injection, the unburned components generated in the post-injection are oxidized by the oxidation catalyst device 24 or the particulate filter 27 carrying the oxidation catalyst to raise the temperature thereof, and the filter 27 is quickly regenerated. With the goal. Further, the purpose of changing the opening of the intake throttle valve 15 to a smaller opening than that during non-regeneration is to suppress the cooling of the filter 27 due to the inflow of fresh air and to increase the temperature efficiently.
[0040]
By the way, if any one of the pressure sensors 26 and 28 and the second exhaust temperature sensor 25 is abnormal, the trapped amount W cannot be estimated or its accuracy is lowered. In such a case, if the engine 1 continues the normal operation state, the filter 27 may be clogged, resulting in a failure of the filter 27 or the like. Therefore, in the control device for the engine 1 according to the present embodiment, if any one of the pressure sensors 26 and 28 and the second exhaust temperature sensor 25 has an abnormality, the engine is controlled and filtered. 27 for controlling clogging.
[0041]
The details of the clogging suppression control when the sensor is abnormal will be described below with reference to the flowchart of FIG.
[0042]
First, in step S1, the control unit 50 detects the temperature T of the particulate filter 27 (detected by the second exhaust temperature sensor 25), the exhaust pressure upstream of the filter 27 (detected by the upstream pressure sensor 26). ) And downstream exhaust pressure (detected by the downstream pressure sensor 28), and various state quantities detected by the sensors such as the engine speed. In addition, the differential pressure is calculated based on the detected upstream exhaust pressure and downstream exhaust pressure. Next, in step S2, the collected amount W is calculated based on the detected temperature T of the particulate filter 27 and the calculated differential pressure.
[0043]
  Next, in step S3, it is determined whether or not the flag F2 is 1. If NO, that is, if the flag F2 is not 1, it is determined in step S4 whether or not the collected amount W is equal to or greater than a predetermined value α. Do (FirstCollected amount determination means). Here, the initial value of the flag F2 is 0, and is set to 1 in step S17 when the collected amount W becomes equal to or larger than the predetermined value α, and when the collected amount W becomes equal to or smaller than the predetermined value due to regeneration. In step S21, it is reset to zero.
[0044]
When the determination in step S4 is NO, that is, when the collection amount W is not equal to or greater than the predetermined value α, the process proceeds to step S5, and it is determined whether there is an abnormality in the pressure sensors 26, 28 and the second exhaust temperature sensor 25. (Abnormality detection means) Here, the abnormalities of the pressure sensors 26 and 28 and the second exhaust temperature sensor 25 are, for example, when the sensor wiring is disconnected or short-circuited, and the sensor output value is set in advance as shown in FIG. In this step S5, when the output value is within a predetermined range set in advance, it is determined that there is no abnormality (NO), and the output value is set in advance. When deviating from the predetermined range, it is determined as abnormal (YES). When at least one of the pressure sensors 26 and 28 and the second exhaust temperature sensor 25 is abnormal, it is determined as abnormal (YES).
[0045]
When the determination in step S5 is NO, that is, when there is no sensor abnormality, the current collection amount W is stored as the collection amount Wa (collection amount storage means) in step S6, and the operation is performed in step S7. Normal operation is performed based on the state. On the other hand, when the determination in step S5 is YES, that is, when the sensor is abnormal, in step S8, a warning lamp is turned on, and in step S9, it is determined whether or not the flag F3 is 1.
[0046]
When the determination in step S9 is NO, that is, when the flag F3 is not 1, in step S10, the collected amount calculated and stored before one control cycle, that is, immediately before the occurrence of the sensor abnormality (see FIG. 5). ) Of the collected amount Wa is determined to be equal to or greater than a predetermined value δ (second collected amount determination means). Here, the initial value of the flag F3 is 0, and is set to 1 in step S13 when the collection amount Wa is equal to or greater than the predetermined value δ. Here, the predetermined value δ is set to a value smaller than the predetermined value α.
[0047]
When the determination in step S10 is NO, that is, when the collection amount Wa immediately before the occurrence of the sensor abnormality is not equal to or greater than the predetermined value δ, EGR is cut in step S11 (clogging suppression means, exhaust gas recirculation amount). Reduction means). On the other hand, when the determination in step S10 is YES, that is, when the collected amount Wa immediately before the occurrence of the sensor abnormality is equal to or greater than the predetermined value δ, the regeneration time C2 is set based on the collected amount Wa in step S12 ( In step S13, the flag F3 is set to 1 in step S13, and the elapsed time Cb is started to be measured in step S14.
[0048]
Next, in step S15, it is determined whether or not this elapsed time Cb is smaller than the reproduction time C2. If YES, that is, if the elapsed time Cb is less than or equal to the reproduction time C2, reproduction is executed in step S15. (Reproduction means) When NO, that is, when the elapsed time Cb is not equal to or less than the reproduction time C2, the EGR is cut (decreased) in step S11. That is, after the regeneration is executed for the regeneration time C2 calculated based on the collection amount Wa, the EGR is cut.
[0049]
On the other hand, when the determination in step S4 is YES, that is, when the current collection amount W is greater than or equal to the predetermined value α, the process proceeds to step S17, and 1 is set in the flag F2. Next, in step S18, whether or not the pressure sensors 26 and 28 and the second exhaust temperature sensor 25 are abnormal is determined by the same method as in step S5 described above (abnormality detection means). When NO, that is, there is no sensor abnormality. In step S19, the current collection amount W is stored as the collection amount Wa (storage means). Next, the process proceeds to step S20, where it is determined whether or not the collected amount W is equal to or smaller than a predetermined value β, that is, whether or not the collected amount W is decreased to a predetermined value β or less by the regeneration control of the filter 27 performed in step S16. To do. The predetermined value β is set to a value smaller than the predetermined value α described above.
[0050]
When the determination in step S20 is NO, that is, when the collected amount W is not equal to or less than the predetermined value β, the regeneration of the filter 27 is performed in step S16 (regeneration means). On the other hand, when the determination in step S20 is YES, that is, when the collected amount W is equal to or less than the predetermined value β, the flag F2 is set to 0 in step S21, and the normal operation control based on the operation state is performed in step S7. Go to step S1. That is, the reproduction of the filter 27 is finished, and the control shifts to the non-reproduction control.
[0051]
On the other hand, if the determination in step S18 is YES, that is, if the sensor is abnormal, a warning lamp is turned on in step S22, and it is determined in step S23 whether the flag F1 is 1.
[0052]
  If the determination in step S23 is NO, that is, if the flag F1 is not 1, the collected amount calculated and stored in step S24 before one control cycle, that is, the collected amount immediately before the occurrence of the sensor abnormality. Based on Wa, the playback duration C1 isAs well as calculatingIn step S25, 1 is set in the flag F1, and the elapsed time Ca is started to be measured in step S26. Here, the characteristics of the regeneration duration C1 with respect to the collection amount Wa are set as shown in FIG. 6, and the value of the regeneration duration C1 is collected when the collection amount Wa is smaller than a predetermined value. The larger the amount Wa, the larger. Here, the purpose of saturating the regeneration continuation time C1 in a region where the collected amount Wa is larger than a predetermined value is to prevent the filter 27 from overheating in a sensor abnormal state.
[0053]
  Next, in step S27, it is determined whether or not this elapsed time Ca is smaller than the reproduction continuation time C1.Playback durationIf it is less than or equal to C1, regeneration is executed in step S16. If NO, that is, if the elapsed time Ca is not less than or equal to the regeneration continuation time C1, only the EGR cut or EGR cut and injection progress are performed in step S28. Run both with horns. That is, when a sensor abnormality occurs when the collection amount W is equal to or greater than the predetermined value α and the regeneration of the filter 27 is being performed, the regeneration duration C1 calculated based on the collection amount Wa immediately before the abnormality occurs. After the regeneration, the EGR valve 31 and the intake throttle valve 15 are controlled to cut the amount of exhaust gas recirculated to the intake side, that is, the EGR cut and the advance angle of the fuel injection timing (to suppress other clogging) Execution means) to suppress clogging of the filter 27. Here, the fuel injection timing is advanced according to the engine speed and the engine load (accelerator opening degree, etc.) even during normal operation.ThatAs shown in FIG. 7A, the advance amount is increased as the engine speed is increased and the engine load is increased. However, the advance angle control for suppressing the clogging is performed as shown in FIG. In addition to the basic advance amount determined from the map, a predetermined advance amount (for example, 2 °), additional advance in a predetermined region (clogging suppression advance angle region) excluding the high load high rotation region shown in FIG. Is to do the corner. In other words, outside the predetermined region, the additional advance angle for suppressing clogging is not performed, and only the EGR cut is performed. And according to this additional advance for suppressing clogging, the amount of NO2 exhausted from the combustion chamber increases and combustion of exhaust particulates by the filter 27 is promoted. As a result, clogging, The accompanying abnormal combustion will be prevented. Moreover, according to the EGR cut, the amount of exhaust particulate discharged from the combustion chamber is suppressed, and as a result, clogging and accompanying abnormal combustion are prevented.
[0054]
Next, another example of clogging suppression control will be described using the flowchart of FIG. The control from step S31 to S38 is the same as the control from step S1 to S8 in the flowchart of FIG. 4, and the control from step S42 to S53 is the same as the control from step S17 to S27 in the flowchart of FIG. Therefore, the description thereof is omitted, and different portions will be mainly described.
[0055]
First, when the determination in step S35 is YES, that is, when the sensor is abnormal, in step S38, the warning lamp is turned on, and in step S39, the collected amount calculated and stored one control cycle before, That is, it is determined whether or not the collection amount Wa immediately before the occurrence of the sensor abnormality is equal to or greater than a predetermined value δ (second collection amount determination means).
[0056]
When the determination in step S39 is NO, that is, when the collection amount Wa immediately before the occurrence of the sensor abnormality is not equal to or greater than the predetermined value δ, EGR is cut in step S40. On the other hand, when the determination in step S40 is YES, that is, when the collection amount Wa immediately before the occurrence of sensor abnormality is equal to or greater than the predetermined value δ, EGR cut and injection advance angle are executed in step S41. That is, it is determined whether to execute only the EGR cut or both the EGR cut and the injection advance angle depending on whether or not the collected amount Wa immediately before the occurrence of the abnormality is equal to or greater than the predetermined value δ.
[0057]
In the case of this flowchart, the process in step S53 (corresponding to the process in step S27 in the flowchart shown in FIG. 3) is NO, that is, the process when the elapsed time Ca exceeds the playback duration C1 is different. That is, when this determination is NO, both EGR cut and injection advance angle are always executed. That is, the clogging is strongly suppressed.
[0058]
  As described above, the engine 1 according to the present embodiment is a parameter value related to the collection amount W of exhaust particulates collected by the particulate filter 27 provided in the exhaust passage 20 of the engine 1. Pressure sensors 26 and 28 for detecting upstream and downstream exhaust pressure and temperature T, and a second exhaust temperature sensor 25 (parameter value detection means);And comprising the control unit 50, the aboveDetect abnormalities in sensors 25, 26, and 28Abnormality detection meansThe amount of exhaust particulates (collected amount W) collected by the particulate filter 27 based on the upstream and downstream exhaust pressures and the temperature T detected by the pressure sensors 26 and 28 and the second exhaust temperature sensor 25. )Collected amount estimation meansWhen,Collected amount estimating meansIt is determined whether or not the collection amount W estimated in step S is equal to or greater than a predetermined amount α.Collected amount judgment meansWhen,Collected amount judging meansWhen the trapped amount W is determined to be equal to or greater than the predetermined amount α, the exhaust particles collected by the filter 27 are burned and removed to regenerate the filter 27.Reproduction meansAnd withAbnormality detection meansWhen the abnormality of the pressure sensors 26 and 28 and the second exhaust temperature sensor 25 is detected by the control, the operating state of the engine 1 is controlled and exhaust particulates are clogged in the particulate filter 27 compared to when no abnormality is detected. To suppressClogging suppression meansIs provided.
[0059]
  According to this,Abnormality detection meansWhen an abnormality is detected in the pressure sensors 26 and 28 and the second exhaust temperature sensor 25, the operating state of the engine 1 is controlled and exhaust particulates are clogged in the particulate filter 27 compared to when no abnormality is detected. Therefore, clogging of the filter 27 when the pressure sensors 26 and 28 and the second exhaust temperature sensor 25 are abnormal, and failure of the filter 27 due to abnormal combustion associated therewith are prevented.
[0060]
  Also, the engine 1Clogging suppression meansIsAbnormality detection meansWhen the abnormality of the pressure sensors 26 and 28 and the second exhaust temperature sensor 25 is detected by EGR, the exhaust gas is recirculated to the intake side in accordance with the operating state of the engine 1 compared to when no abnormality is detected. The valve 31 (exhaust gas recirculation means) is controlled to reduce the recirculation amount of the exhaust gas to the intake side, and the fuel injection timing is controlled.Fuel injection control meansIs controlled to advance the injection timing.
[0061]
  According to this,Abnormality detection meansWhen an abnormality is detected in the pressure sensors 26 and 28 and the second exhaust temperature sensor 25, the comparison is made when no abnormality is detected.EGR valve 31To control the amount of exhaust gas recirculation to the intake side and control the fuel injection timingFuel injection control meansIs controlled to advance the injection timing.
[0062]
  That is,EGR valve 31If the exhaust gas recirculation amount to the intake side is reduced by controlling the exhaust gas, the emission amount of exhaust particulate discharged from the combustion chamber is suppressed, and as a result, clogging and accompanying abnormal combustion are prevented. . Also controls the fuel injection timingFuel injection control meansIf the injection timing is advanced by controlling the control, the amount of NO2 exhausted from the combustion chamber is increased, and the combustion of exhaust particulates by the particulate filter 27 is promoted. As a result, clogging is accompanied by this. Abnormal combustion is prevented. Moreover, if both of these are implemented, these will be prevented more effectively.
[0063]
  And this engine 1 isConsists of the control unit 50, and the collected amount estimating meansMemorize the collection amount W estimated byCollected amount storage meansWhen,Abnormality detection meansWhen an abnormality in the pressure sensors 26, 28 and the second exhaust temperature sensor 25 is detected by theCollected amount storage meansIt is determined whether or not the collected amount Wa stored in (2) is equal to or greater than the (second) predetermined amount δ.Second collection amount determination meansWhen,The second collected amount judging meansWhen the collected amount Wa is determined to be greater than or equal to the predetermined amount δ,The collected amount storage meansAccording to the collection amount Wa stored inReproduction meansSet the operation period C2Playback period setting meansAndClogging suppression meansIsThe second collected amount judging meansImmediately before detecting an abnormalityCollected amount storage meansWhen it is determined that the collected amount Wa stored in is equal to or greater than the predetermined amount δ,Reproduction meansBut,Reproduction period setting meansAfter the regeneration of the filter 27 is executed during the operation period C2 set by the above, clogging is suppressed.
[0064]
  According to this,Abnormality detection meansWhen an abnormality in the pressure sensors 26, 28 and the second exhaust temperature sensor 25 is detected by theCollected amount storage meansIt is determined whether or not the collected amount Wa stored in step S is equal to or greater than a predetermined amount δ. When it is determined that the collected amount Wa is equal to or greater than the predetermined amount δ,Reproduction meansBut,Playback period setting meansSince the filter 27 is regenerated during the operation period C2 set by the above to reduce the collection amount of exhaust particulates and clogging is suppressed, clogging when the collection amount is large is performed. In addition, abnormal combustion associated therewith is reliably prevented.
[0065]
  Furthermore, the engine 1Clogging suppression meansIsAbnormality detection meansWhen the abnormality of the pressure sensors 26 and 28 and the second exhaust temperature sensor 25 is detected bySecond collection amount determination meansWhen the collected amount Wa is determined to be equal to or greater than the predetermined amount δ,EGR valve 31To control the amount of exhaust gas recirculation to the intake side and control the fuel injection timingFuel injection control meansTo control the injection timing and advance the injection timing,Second collection amount determination meansWhen it is determined that the amount is not greater than or equal to the predetermined amount δ, only the recirculation amount of the exhaust gas is reduced by controlling the EGR valve 31.
[0066]
  According to this,Abnormality detection meansWhen the abnormality of the pressure sensors 26 and 28 and the second exhaust temperature sensor 25 is detected bySecond collection amount determination meansWhen it is determined that the collected amount Wa immediately before the occurrence of the abnormality is not equal to or greater than the predetermined amount δ, the EGR valve 31 is controlled to reduce the recirculation amount of the exhaust gas. Abnormal combustion associated therewith is reliably prevented, and since the advance of the injection timing is not performed, noise that is likely to occur by advancing the injection timing is prevented.
[0067]
  on the other hand,Abnormality detection meansWhen the abnormality of the pressure sensors 26 and 28 and the second exhaust temperature sensor 25 is detected bySecond collection amount determination meansWhen the collected amount Wa immediately before the occurrence of the abnormality is determined to be greater than or equal to the predetermined amount δ, the EGR valve 31 is controlled to reduce the recirculation amount of the exhaust gas to the intake side, and the fuel injection timing is controlled.Fuel injection control meansTherefore, the filter 27 is more reliably prevented from being clogged and accompanying abnormal combustion than the case where only one is performed.
[0068]
  Also, the engine 1Clogging suppression meansControls the EGR valve 31 that recirculates the exhaust gas to the intake side in accordance with the operating state of the engine 1 to reduce the recirculation amount of the exhaust gas.Exhaust gas recirculation amount reduction meansA plurality including at leastClogging suppression execution meansHaveAbnormality detection meansWhen the abnormality of the pressure sensors 26 and 28 and the second exhaust temperature sensor 25 is detected byExhaust gas recirculation amount reduction meansTheOther clogging suppression execution meansPriority is given to operation.
[0069]
  According to this,Abnormality detection meansWhen an abnormality is detected by theExhaust gas recirculation amount reduction meansButOther clogging suppression execution meansTherefore, the filter 27 can be effectively prevented from being clogged,Other clogging suppression execution meansIt is possible to suppress harmful effects caused by operating the.
[0070]
  Also, the engine 1Clogging suppression meansIsSecond collection amount determination meansWhen the collected amount Wa is determined to be equal to or greater than the predetermined amount δ,Exhaust gas recirculation amount reduction meansAs well asOther clogging suppression execution meansIs activated.
[0071]
  According to this,Exhaust gas recirculation amount reduction meansnot onlyOther clogging suppression execution meansBy operating the, the clogging of the filter 27 is strongly suppressed.
[0072]
  In addition, the engine 1Collected amount estimation meansIt is determined whether or not the collection amount W estimated in step S is equal to or greater than a predetermined amount α.Collected amount judgment meansWhen,Collected amount judging meansWhen the trapped amount W is determined to be equal to or greater than the predetermined amount α, the exhaust particles collected by the filter 27 are burned and removed to regenerate the filter 27.Reproduction meansAnd abnormalities of the pressure sensors 26 and 28 and the second exhaust temperature sensor 25 are detected.Abnormality detection meansAnd withCollected amount estimation meansIs stored as the collection amount Wa.Collected amount storage meansAnd during the regeneration of the filter 27Abnormality detection meansWhen an abnormality in the pressure sensors 26, 28 and the second exhaust temperature sensor 25 is detected by theThe collected amount storage meansDepending on the pre-abnormal collection amount Wa stored inReproduction meansSet the playback duration C1Playback duration setting meansAndReproduction meansDuring playbackAbnormality detection meansWhen the abnormality of the pressure sensors 26 and 28 and the second exhaust temperature sensor 25 is detected byReproduction duration setting meansThe regeneration of the filter 27 is continued during the regeneration continuation period C1 set by.
[0073]
  According to this, during regeneration of the filter 27,Abnormality detection meansWhen the abnormality of the pressure sensors 26 and 28 and the second exhaust temperature sensor 25 is detected byPlayback duration setting meansSince the regeneration of the filter 27 is continued during the regeneration continuation period C1 set by the above, the collected exhaust particulates are surely reduced, and as a result, the filter 27 is clogged, abnormal combustion accompanying this, etc. Is prevented.
[0074]
In addition, since the regeneration continuation period C1 is set according to the pre-abnormal collection amount Wa, it is possible to reliably prevent an excessive temperature rise of the filter 27 due to unnecessary regeneration for a long time, a failure of the filter 27 accompanying this, etc. To be prevented.
[0075]
  Also, the engine 1Clogging suppression meansIsReproduction meansHowever, the filter 27 is prevented from being clogged after the regeneration of the filter 27 is continued during the regeneration continuation period C1.
[0076]
  According to this,Clogging suppression meansIsReproduction meansHowever, after the regeneration of the filter 27 is continued during the regeneration continuation period C1, clogging is suppressed, so that clogging and abnormal combustion associated therewith can be reliably prevented.
[0077]
In addition, although this Embodiment demonstrated the case of the diesel engine, this clogging suppression control is widely applicable also to a gasoline engine.
[0078]
【The invention's effect】
As described above, according to the present invention, the pressure sensor and the exhaust temperature for detecting the upstream and downstream exhaust pressures and temperatures as parameter values related to the collection amount of the exhaust particulates collected by the particulate filter. When an abnormality in the sensor is detected, the operating state of the engine is controlled to prevent the exhaust particulate from clogging the particulate filter compared to when no abnormality is detected. It is possible to prevent clogging and accompanying abnormal combustion.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram of an engine according to an embodiment of the present invention.
FIG. 2 is a map of EGR amount characteristics with respect to engine speed and engine load.
FIG. 3 is a map used when estimating the collection amount from the differential pressure and temperature.
FIG. 4 is a flowchart illustrating an example of clogging suppression control.
FIG. 5 is an explanatory diagram of sensor abnormality.
FIG. 6 is a map of characteristics with respect to the amount collected during the regeneration continuation period.
FIG. 7 is a map of injection advance characteristics with respect to engine speed and engine load.
FIG. 8 is a flowchart showing another example of clogging suppression control.
[Explanation of symbols]
1 engine
10 Intake passage
15 Inlet throttle valve
16 Inlet throttle valve opening sensor
20 Exhaust passage
25 Second exhaust temperature sensor (parameter value detection means)
26, 28 Pressure sensor (parameter value detection means)
27 Particulate filter (collecting means)
31 EGR valve 31 (exhaust gas recirculation means)
50 Control unit (abnormality detection means, clogging suppression means, fuel injection control means, collection amount estimation means, collection amount storage means, collection amount determination means, regeneration means, regeneration period setting means, exhaust gas recirculation amount reduction means , Clogging suppression execution means, second collected amount determination means, regeneration duration setting means)

Claims (4)

Parameter value detection means for detecting a parameter value related to the collection amount of exhaust particulates collected in the collection means provided in the exhaust passage of the engine;
A collection amount estimation means for estimating the exhaust particulate amount trapped in the said collecting means on the basis of the detected parameter values the parameter value detection means,
A first trapped amount judgment means for judging whether or not the first predetermined amount or more trapped amount estimated is predetermined by said trapped amount estimation means,
When the amount collected by the first collecting quantity determining means determines that said first predetermined amount or more, regeneration for regenerating the trapping means the exhaust particulate matter is burned and removed trapped in the said collecting means An engine control device provided with means,
A collected amount storage means for storing the collected amount estimated by the collected amount estimating means;
An abnormality detecting means for detecting an abnormality of the parameter value detecting means ;
When the abnormality of the parameter value detection means is detected by the abnormality detection means, the second collection for determining whether or not the collection amount stored in the collection amount storage means immediately before the abnormality detection is equal to or greater than a second predetermined amount A quantity determination means;
When the collected amount determining means determines that the collected amount is equal to or greater than the second predetermined amount, the operation period of the regenerating means is set according to the collected amount stored in the collected amount storage means immediately before the abnormality is detected. A playback period setting means to be set ;
When abnormal parameter value detection means is detected by said abnormality detecting means, abnormality than when not detected, to control the operating state of the engine so that the exhaust particulates clogging the collecting means is suppressed At the same time, when an abnormality is detected in the parameter value detection means, the collection amount stored in the collection amount storage means immediately before the abnormality detection is determined by the second collection amount determination means to be greater than or equal to a second predetermined amount. The clogging restraining means for controlling the clogging of the collecting means after the regeneration means performs regeneration of the collecting means during the operation period set by the regeneration period setting means. An engine control device characterized by being provided. The clogging suppression means is an exhaust gas that recirculates exhaust gas to the intake side according to the operating state of the engine when the abnormality detection means detects an abnormality of the parameter value detection means compared to when no abnormality is detected. characterized by performing a control for controlling the recirculation means decreases the amount of recirculated exhaust gas to the intake side by controlling the fuel injection control means for controlling the fuel injection timing of the control to advance the injection timing at least one of the The engine control device according to claim 1. Parameter value detection means for detecting a parameter value related to the collection amount of exhaust particulates collected in the collection means provided in the exhaust passage of the engine;
A collected amount estimating means for estimating the amount of exhaust particulates collected by the collecting means based on the parameter value detected by the parameter value detecting means;
First collected amount determining means for determining whether the collected amount estimated by the collected amount estimating means is greater than or equal to a predetermined first predetermined amount;
Regeneration in which the collection means is regenerated by burning and removing the exhaust particulates collected by the collection means when the collection quantity is determined to be greater than or equal to the first predetermined amount by the first collection quantity determination means. An engine control device provided with means,
An abnormality detecting means for detecting an abnormality of the parameter value detecting means;
When the abnormality of the parameter value detection means is detected by the abnormality detection means, the exhaust gas recirculation means for recirculating the exhaust gas to the intake side is controlled according to the operating state of the engine, compared to when no abnormality is detected. By controlling at least one of the control to reduce the recirculation amount of the exhaust gas to the intake side and the control to advance the injection timing by controlling the fuel injection control means for controlling the fuel injection timing, the exhaust particulates are collected. Clogging suppression means for suppressing clogging in the means;
And trapped amount storage means for storing the trapped amount estimated by the trapped amount estimation means,
When abnormality of the parameter value detection means is detected by the abnormality detecting means determines whether the second predetermined quantity or more trapped amount stored is predetermined by the trapped amount storage means abnormality detection immediately before A second collection amount judging means,
The clogging suppression means controls the exhaust gas recirculation means to return the exhaust gas to the intake side when the collected amount is determined to be greater than or equal to the second predetermined amount by the second collected amount determining means. a control for reducing the flow rate control to the injection timing of the fuel injection control means performs both the control to advance, the amount collected by the second collecting quantity determining means is determined not to be the second predetermined amount or more In this case, the engine control device is characterized in that only the control for reducing the exhaust gas recirculation amount is performed by controlling the exhaust gas recirculation means. Parameter value detection means for detecting a parameter value related to the collection amount of exhaust particulates collected in the collection means provided in the exhaust passage of the engine;
A collected amount estimating means for estimating the amount of exhaust particulates collected by the collecting means based on the parameter value detected by the parameter value detecting means;
First collected amount determining means for determining whether the collected amount estimated by the collected amount estimating means is greater than or equal to a predetermined first predetermined amount;
Regeneration in which the collection means is regenerated by burning and removing the exhaust particulates collected by the collection means when the collection quantity is determined to be greater than or equal to the first predetermined amount by the first collection quantity determination means. An engine control device provided with means,
An abnormality detecting means for detecting an abnormality of the parameter value detecting means;
A plurality of clogging suppression execution means including at least exhaust gas recirculation amount reducing means for reducing exhaust gas recirculation amount by controlling exhaust gas recirculation means that recirculates exhaust gas to the intake side according to the operating state of the engine; When the abnormality of the parameter value detecting means is detected by the abnormality detecting means, the exhaust gas recirculation amount reducing means is operated in preference to the other clogging suppression executing means, so that the exhaust particulates are attracted to the collecting means. Clogging suppressing means for suppressing clogging;
And trapped amount storage means for storing the trapped amount estimated by the trapped amount estimation means,
When abnormality of the parameter value detection means is detected by the abnormality detecting means determines whether the second predetermined quantity or more trapped amount stored is predetermined by the trapped amount storage means abnormality detection immediately before A second collection amount judging means,
And, the clogging suppression means, the when the amount collected is determined to the second predetermined amount or more by the second trapped amount judgment means, other clogging suppression performed with operating the exhaust gas recirculation amount-reducing means An engine control device characterized by operating means.

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