JP2012026428A - Exhaust emission control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make compatible both the sure restraint of the progress of oil dilution and an improvement in fuel consumption efficiency, in an exhaust emission control device of an internal combustion engine.SOLUTION: The exhaust emission control device of the internal combustion engine 2 includes a filter 60 for collecting particulate matters in exhaust gas, a storage means 95 for storing actual result data on the past operation state and filter regeneration processing, an oil dilution degree predictor calculating means 70 for calculating an oil dilution degree predictor by using the past data stored in the storage means 95, an oil dilution degree predictor determining means 80 for determining whether or not the oil dilution degree predictor is larger than a threshold, a first regeneration means, a second regeneration means in which an oil dilution quantity is small and the fuel consumption ratio is high by the first regeneration means, and a selecting means 90 for selecting the first regeneration means when determining that the oil dilution degree predictor is the threshold or smaller and selecting the second regeneration means when determining that the oil dilution degree predictor is larger than the threshold.

Description

  The present invention relates to an exhaust gas purification apparatus for an internal combustion engine equipped with, for example, a diesel particulate filter (hereinafter referred to as “DPF” as appropriate) that can capture and regenerate particulate matter in the exhaust gas of the internal combustion engine.

  For example, for a vehicle using a diesel engine as an internal combustion engine, a diesel part for collecting particulate matter (hereinafter referred to as “PM (Particulate Matter)”) in the exhaust on an exhaust passage of the internal combustion engine. Some have an exhaust purification device provided with a curate filter. In the DPF, in order to prevent the filter from being clogged due to the accumulation of PM and reducing the power performance of the internal combustion engine or the like, a PM regeneration process for burning the accumulated PM according to the amount of collected PM is performed. The PM regeneration process is performed, for example, by increasing the output of the internal combustion engine, thereby increasing the exhaust temperature in the exhaust passage where the DPF is disposed, and burning the accumulated PM.

For example, in Patent Document 1, when the vehicle is stopped (idling state), the operation of the driver (for example, the operation of the driver pressing a PM regeneration start button or the like) temporarily increases the rotational speed of the internal combustion engine and combustion A technique relating to manual PM regeneration processing is disclosed in which exhaust temperature is increased by post-injecting fuel into a combustion chamber at a time when it does not contribute to combustion, and particulate matter accumulated in the DPF is combusted. Here, if the fuel is post-injected into the combustion chamber in the PM regeneration process at a time when it does not contribute to combustion, the post-injected fuel adheres to the inner wall of the cylinder, and the adhering fuel falls to an oil pan or the like and becomes engine oil. By mixing, there is a problem that the oil is diluted and causes problems such as seizure in the internal combustion engine.
In order to solve such a problem, Patent Document 1 provides an oil dilution estimation means for estimating the degree of oil dilution that indicates how much the oil has been diluted by the fuel. When it is estimated that the value is large, a control for urging the driver to perform manual regeneration is performed by turning on a warning light.

Patent Document 2 discloses a technique for performing PM regeneration processing by appropriately switching between a first regeneration unit and a second regeneration unit that have different post injection timings.
When the PM regeneration process is performed using the first regeneration means, it is possible to achieve good fuel efficiency although oil dilution is more likely to proceed than the second regeneration means. On the other hand, when the PM regeneration process is performed using the second regeneration means, although the oil dilution is difficult to proceed as compared with the first regeneration means, the fuel efficiency is deteriorated. In Patent Document 2, it is shown that the first regeneration means and the second regeneration means having the degree of progress of oil dilution and the fuel efficiency, which are contradictory to each other, are controlled to be switched.

JP 2008-202573 A JP 2008-297969 A

  However, Patent Document 1 shows that warning means warns when the dilution degree of the lubricating oil is estimated to be relatively large by the dilution degree estimation means that estimates the degree of dilution of the lubricating oil with fuel. It is not shown until the regeneration means for burning the particulate matter deposited on the DPF is switched according to the estimated degree of dilution.

Japanese Patent Laid-Open No. 2004-228561 discloses switching control between two types of PM regeneration processing, ie, a regeneration unit in which oil dilution is likely to proceed and a regeneration unit in which it is difficult to proceed. The oil dilution amount is calculated from the regeneration time and operating state of the DPF, and when the dilution amount exceeds a predetermined value, the regeneration means is used so that the dilution amount decreases.
That is, in Patent Document 2, a regeneration unit that reduces the dilution amount when the dilution amount exceeds a predetermined value is applied, and the regeneration unit is changed after the degree of oil dilution progresses. This delays the progress of the degree of dilution. Therefore, even if the regeneration means is changed in a state where the degree of oil dilution has progressed, if the low-load operation with a small amount of evaporation from the oil continues thereafter, dilution proceeds to a level that requires oil replacement. There is a problem, and there is a problem that an increase in the degree of oil dilution cannot be reliably prevented.

  Accordingly, the present invention has been made in view of the above-described problems, and an object of the present invention is to provide an exhaust purification device for an internal combustion engine that can achieve both a reliable suppression of the progress of oil dilution and an improvement in fuel efficiency.

  In order to solve the above problems, an exhaust gas purification apparatus for an internal combustion engine of the present invention is an exhaust gas purification apparatus for an internal combustion engine comprising a filter that collects particulate matter contained in the exhaust gas of the internal combustion engine. Using the past data stored in the storage means and the storage means for storing the past operation state and the actual data relating to the filter regeneration process, and the oil dilution expected value that is the expected value of the oil dilution in the internal combustion engine An oil dilution expected value calculating means for calculating, an oil dilution expected value determining means for determining whether or not the calculated oil dilution expected value is larger than a predetermined threshold value, and the collected particulate matter A first regenerating means capable of regenerating the filter by burning the substance, and a regenerating means capable of regenerating the filter by burning the collected particulate matter. The predicted oil dilution value calculated by the second regeneration means having a lower oil dilution amount and a higher fuel consumption rate than the first regeneration means and the predicted oil dilution value determination means is less than or equal to the threshold value. If it is determined that there is, the first regeneration unit is selected from the two regeneration units, the filter is regenerated, and the oil dilution predicted value calculated by the oil dilution predicted value determination unit is When it is determined that the threshold value is larger than the threshold, the first reproduction unit and the second reproduction unit are selected so that the second reproduction unit is selected from the two reproduction units and the filter is reproduced. And selecting means for controlling.

According to this invention, the oil dilution amount is lower and the fuel consumption rate is higher than the first regeneration means and the first regeneration means based on the magnitude of the predicted value of the oil dilution calculated based on the past data. By performing control to switch between the two regeneration means, it is possible to achieve both suppression of the progress of oil dilution and improvement of the fuel consumption rate.
Also, in order to switch between the first regeneration means and the second regeneration means based on the magnitude of the oil dilution prediction value, that is, to switch based on the oil dilution prediction value, the oil dilution actually progressed. Rather than making a determination based on the dilution amount of the state, an increase in oil dilution can be reliably prevented.

  Preferably, in the present invention, the predicted oil dilution value calculation means predicts the next filter regeneration processing timing before starting the filter regeneration process, and stores the oil dilution degree at that time in the storage means. Predicting based on the past data that has been made, the predicted oil dilution value determining means may determine the size of the threshold using the predicted oil dilution.

  Further, the actual data relating to the filter regeneration processing stored in the storage means includes the oil dilution amount by the first regeneration means, the oil dilution amount by the second regeneration means, and the execution of the first regeneration means. , A time interval until the second regeneration means is implemented, and data relating to the amount of oil evaporation may be stored in a map.

  By configuring in this way, before starting the regeneration processing of the filter, based on the past regeneration processing conditions of the internal combustion engine, the oil dilution amount by the regeneration processing, and the actual data such as the amount of oil evaporation based on the operating state, etc. The next filter regeneration processing timing is predicted, and the predicted value of the oil dilution amount (dilution degree) at that time is used, and a more preferable selection of the first regeneration unit and the second regeneration unit is possible. As a result, the DPF regeneration means that does not increase the oil dilution can be selected at an earlier stage, and an increase in the oil dilution can be reliably prevented.

  In the present invention, it is preferable that the predicted oil dilution value calculation unit is configured to determine the load and rotation speed of the internal combustion engine within a predetermined period based on the operation state data stored in the storage unit. The ratio that is in the oil dilution progress region determined by is calculated, and the dilution expected value determination means may determine the size of the threshold using the calculated ratio in the oil dilution progress region.

According to such a configuration, it is determined whether or not the operating state in which the dilution progresses based on the ratio within the oil dilution progress region determined by the load and rotation speed of the internal combustion engine, that is, the frequency within this region within a predetermined time. To do.
When it is determined that the ratio within the oil dilution progress region is larger than the threshold, the oil dilution progresses quickly, so the second regeneration means that is the regeneration means with a low oil dilution amount is selected, and the threshold is set. If it is determined as follows, the first reproduction means is selected to perform reproduction.
In this way, the frequency of the operating state in which the progress of the oil dilution is fast is used as the predicted value of the oil dilution, and the DPF regeneration means that does not increase the oil dilution is selected. Even when this is shown, appropriate switching control can be realized, and an increase in the oil dilution can be reliably prevented.

  Preferably, in the present invention, the first regeneration unit and the second regeneration unit may post-inject fuel at different timings, and the first regeneration unit is an automatic PM regeneration process, The second regeneration means may be manual PM regeneration processing.

Since the manual PM regeneration process is executed when the engine is in an idling state, the oil dilution can be adjusted to be reduced by optimizing the post injection timing and the post injection amount.
On the other hand, in the automatic PM regeneration process, the state of the engine changes from moment to moment according to the use conditions, so the post injection timing and the post injection amount must be optimized under various operating conditions, and the oil dilution level is It is difficult to make adjustments to reduce the number.
Therefore, manual PM regeneration processing tends to make oil dilution difficult to proceed compared to automatic PM regeneration processing. In the present invention, the first regeneration means is an automatic PM regeneration process, and oil dilution is performed by the first regeneration means. By selecting the second regeneration means having a low amount and a high fuel consumption rate as the manual PM regeneration process, an increase in the oil dilution can be surely prevented.

According to the exhaust gas purification apparatus for an internal combustion engine according to the present invention, the progress of oil dilution is suppressed by switching between the first regeneration means and the second regeneration means based on the magnitude of the predicted value of the oil dilution. And improving the fuel consumption rate.
The predicted value of the oil dilution is calculated as an estimated value based on past performance data of the internal combustion engine (for example, past travel data of a vehicle in which the internal combustion engine is mounted). Switching control is possible.
Further, even when the operation state of the internal combustion engine shows a complicated change from moment to moment by performing switching control based on whether or not the ratio that the operation state is in the oil dilution progress region is larger than the threshold value. Appropriate switching control can be realized.

It is the schematic which shows the structure of the engine periphery to which the exhaust gas purification apparatus which concerns on this embodiment is applied. It is a flowchart figure of the manual PM reproduction | regeneration process in the exhaust gas purification apparatus which concerns on this embodiment. It is a flowchart figure of the automatic PM reproduction | regeneration process in the exhaust gas purification apparatus which concerns on this embodiment. It is a flowchart figure which shows operation | movement of the exhaust gas purification apparatus which concerns on 1st Example. It is a flowchart figure of the subroutine process for calculating PM deposition amount M which concerns on 1st Example. FIG. 6 is a graph showing time-series changes in PM stacking amount M and oil dilution when an automatic PM regeneration process is performed in the exhaust gas purification apparatus according to the first embodiment. In the exhaust gas purification apparatus according to the first embodiment, it is a graph showing the time series change of the PM stacking amount M and the oil dilution when a manual PM regeneration process is performed. It is a flowchart figure which shows operation | movement of the exhaust gas purification apparatus which concerns on 2nd Example. It is a flowchart figure of the subroutine for calculating the frequency in a dilution progress area | region. It is a graph which shows the oil dilution with respect to the engine speed-engine torque of the engine which concerns on 2nd Example.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

(overall structure)
FIG. 1 is a schematic view showing a configuration around an engine to which an exhaust gas purification apparatus for an internal combustion engine according to the present embodiment is applied. In FIG. 1, the engine 2 is a four-cycle diesel engine having four cylinders. An intake passage 8 is connected to the engine 2 through an intake manifold 6 and an exhaust passage 12 is connected through an exhaust manifold 10.

  The intake passage 8 is provided with a compressor 14 a of the turbocharger 14. The compressor 14 a is coaxially driven by a turbine 14 b provided in the exhaust passage 12. An intercooler 16 for exchanging heat between the intake air flowing through the intake passage 8 and the atmosphere is provided downstream of the compressor 14 a in the intake passage 8. Further, a throttle valve 18 for adjusting the flow rate of the intake air flowing through the intake passage 8 is provided on the downstream side of the intercooler 16 in the intake passage 8.

  The intake passage 8 is provided with an air flow meter 26 for detecting the intake flow rate upstream of the compressor 14a, and a temperature sensor 28 and a pressure sensor 30 are provided on the intake manifold 6 on the downstream side of the throttle valve 18. Yes.

  In the exhaust passage 12, a turbine 14b of the turbocharger 14 is provided. The turbine 14 b is driven by exhaust gas from the engine 2. Further, the exhaust manifold 10 is provided with an EGR passage 20 for recirculating a part of the exhaust gas to the intake manifold 6. The EGR passage 20 is provided with an EGR cooler 22 and an EGR control valve 24.

  The EGR cooler 22 is provided closer to the exhaust manifold 10 than the EGR control valve 24. The EGR cooler 22 exchanges heat between the EGR gas passing through the EGR cooler 22 and the cooling water to lower the temperature of the EGR gas. The EGR control valve 24 controls the flow rate of EGR gas flowing through the EGR passage 20.

  In the ECU 40, the CPU 48 calculates the target opening degree of the EGR control valve 24 and the throttle valve 18 based on the respective input values described above, and the opening degree of the EGR control valve 24 and the throttle valve 18 via the drive circuits 43 and 44. To control.

  Detection values of the air flow meter 26, the temperature sensor 28, and the pressure sensor 30 are input to an engine control unit (ECU) 40 through A / D converters 46a, 46b, and 46c, respectively.

  The engine 2 is provided with an engine speed sensor 32, and a detection value of the engine speed sensor 32 is input to the ECU 40 via the pulse count circuit 47.

  The ECU 40 calculates the fuel injection amount to the engine 2 based on the respective input values described above, and controls the fuel injection amount to the engine 2 via the injector drive circuit 41.

  A DPF 60 for collecting PM in the exhaust gas is provided on the downstream side of the turbine 14b in the exhaust passage 12 of the engine 2. The DPF 60 typically has a structure in which a ceramic filter carrier such as cordierite or SiC is accommodated in a metal casing.

  In the DPF 60, in order to prevent clogging due to the accumulation of PM and the deterioration of the power performance of the engine 2 or the like, the PM regeneration for burning the accumulated PM according to the amount of collected PM is based on the control of the ECU 40. As appropriate. The specific contents of PM regeneration control by the ECU 40 will be described in detail later. The DPF 60 is also used with an oxidation catalyst 63 which is a catalytic converter configured to oxidize CO, HC (mainly SOF), NOx and the like in exhaust gas generated when the fuel is burned. Also good.

  The DPF 60 is provided with temperature sensors 61 for detecting exhaust temperatures on the upstream side, the midstream side, and the downstream side in the DPF 60. Further, the DPF 60 is provided with a DPF differential pressure sensor 62 for detecting the differential pressure ΔPdpf in the DPF 60 by detecting the upstream and downstream exhaust pressures in the DPF 60. Each of these various sensors is electrically connected to the ECU 40, and each index value detected by each sensor is referred to by the ECU 40 at a constant or indefinite period.

(PM regeneration process)
In the present embodiment, as an example of the “first reproduction unit” and the “second reproduction unit” according to the present invention, the “first reproduction unit” is an automatic PM regeneration process, and the “second reproduction unit” is Handle as manual PM regeneration process. Here, specific operation contents of the automatic PM regeneration process and the manual PM regeneration process will be described.

  First, the operation of the manual PM regeneration process will be described with reference to FIG. FIG. 2 is a flowchart of manual PM regeneration processing in the exhaust gas purification apparatus according to the present embodiment.

  First, the ECU 40 determines whether or not the PM accumulation amount M in the DPF 60 is larger than the threshold value M1 (step S101). The threshold value M1 may be defined in advance by an experimental, theoretical, or simulation technique as a boundary value that may cause a problem in the engine 2 or the like unless PM is burned by manual regeneration processing.

  When the PM accumulation amount M is larger than the threshold value M1 (step S101: YES), the ECU 40 determines whether or not an execution condition for performing the manual PM regeneration process is satisfied (step S102). The manual PM regeneration process is performed under a condition where the load of the engine 2 is relatively small (for example, an idling condition where the engine speed and the fuel injection amount are relatively small). When it is determined that the condition is satisfied (step S102: YES), the ECU 40 turns on a warning lamp to notify the driver to execute the manual PM regeneration process (step S103). Then, the ECU 40 determines whether or not the driver who has recognized the lighting of the warning light has turned on a switch (not shown) for starting the manual PM regeneration process (step S104). When it is determined that the switch is turned “ON” (step S104: YES), the manual PM regeneration process is executed (step S105), and the process ends (END).

  On the other hand, when the PM accumulation amount M is equal to or less than the threshold value M1 (step S101: NO) or when the above condition is not satisfied (step S102: NO), the ECU 40 turns off the warning lamp (step S106) and ends the process. (END).

  Next, the automatic PM regeneration process will be described with reference to FIG. FIG. 3 is a flowchart of the automatic PM regeneration process in the exhaust purification apparatus according to this embodiment.

  First, the ECU 40 determines whether or not the PM accumulation amount M in the DPF is larger than the threshold value M2 (step S201). Here, the threshold value M2 may be defined in advance by an experimental, theoretical, or simulation method as a boundary value that may cause a problem in the engine 2 or the like unless PM is burned by the automatic PM regeneration process. Note that the threshold value M2 may be the same as or different from the threshold value M1 used in the manual PM regeneration process.

  Subsequently, when the PM accumulation amount M is larger than the threshold value M2 (step S201: YES), the ECU 40 determines whether or not a condition for performing the automatic PM regeneration process is satisfied (step S202). The automatic PM regeneration process is performed in a state where the engine speed and the fuel injection amount of the engine 2 change. In a situation where the load of the engine 2 is extremely low, the oxidation catalyst cannot be activated, so it is determined whether or not the condition is satisfied. And when it determines with satisfy | filling the said conditions (step S202: YES), ECU40 performs an automatic PM reproduction | regeneration process (step S203), and complete | finishes a process (END).

  In the PM regeneration process in step S105 and step S203, for example, the exhaust temperature in the exhaust passage 12 is increased by increasing the engine speed, and the PM accumulated in the DPF 60 is combusted.

  Here, in both the manual PM regeneration process and the automatic PM regeneration process, the PM regeneration process is performed by post-injecting the fuel, so that the engine oil is diluted a little. This is caused by the post-injected fuel adhering in the cylinder constituting the engine 2 and permeating into oil in an oil pan or the like. The degree of oil dilution (i.e., oil dilution) depends on the amount of fuel injected during post-injection remaining without being burned in the engine 2.

The manual PM regeneration process is executed when the engine 2 is in an idling state. Under such a condition, the oil dilution can be adjusted to be reduced by optimizing the post injection timing, the post injection amount, and the air amount. On the other hand, in the automatic PM regeneration process, as described above, the state of the engine 2 changes from moment to moment according to the use conditions, so that the post injection timing, the post injection amount, and the air amount are optimized under various operating conditions. It is necessary and it is difficult to adjust the oil dilution degree to be small. Generally, manual PM regeneration processing has a tendency that oil dilution does not easily proceed as compared with automatic PM regeneration processing, and the description of the present application will be made on the assumption of this.
From the viewpoint of the fuel consumption rate, the manual PM regeneration process is executed when the engine 2 is in an idling state, and therefore, when the vehicle is running or using the vehicle, as in the automatic PM regeneration process. The fuel consumption rate tends to be disadvantageous compared to the automatic PM regeneration process.
Further, the post-injection timings of the manual PM regeneration process and the automatic PM regeneration process are set differently. For example, the manual PM regeneration process is set on the advance side as compared with the automatic PM regeneration process, The PM regeneration process is set so that the oil dilution amount is low and the fuel consumption rate is high.

(First embodiment)
Subsequently, a specific operation of the exhaust gas purification apparatus according to the first embodiment will be described with reference to FIG.
The ECU 40 includes an oil dilution expected value calculation means 70 for calculating an oil dilution expected value that is an expected value of the oil dilution in the engine 2, and the calculated oil dilution expected value is greater than a predetermined threshold. Oil dilution degree prediction value determination means 80 for determining whether or not, and selection means 90 for selecting the first regeneration means and the second regeneration means depending on whether the calculated oil dilution degree prediction value is larger or smaller than the threshold value. And are provided.

  The predicted oil dilution value calculation means 70 is calculated based on past operating state data stored in the storage means 95 and actual data relating to filter regeneration processing. The actual data related to the filter regeneration process is, for example, actual data regarding the oil dilution amount by the automatic PM regeneration process as the first regeneration means, the oil dilution amount by the manual PM regeneration process as the second regeneration means, The time interval until the first regeneration means is implemented, the actual data of the time interval until the second regeneration means is implemented, and the data relating to the oil evaporation amount are stored in a map.

FIG. 4 is a flowchart showing the operation of the exhaust emission control system according to the first embodiment.
First, the ECU 40 calculates the PM accumulation amount M in the DPF 60 (step S301). Specifically, the PM accumulation amount M is calculated by executing a subroutine shown in FIG. FIG. 5 is a flowchart of a subroutine process for calculating the PM accumulation amount M.

  As shown in FIG. 5, first, the ECU 40 acquires the PM emission amount PM1 by detecting the PM emission amount of the engine 2 (step S401). Specifically, the ECU 40 detects the engine speed, and calculates the PM discharge amount PM1 based on a predetermined map of engine speed-fuel injection amount command value-PM discharge amount.

  Subsequently, the ECU 40 calculates the PM combustion amount PM2 (step S402). Specifically, the exhaust gas temperature is detected by the temperature sensor 61 installed in the DPF 60, and the PM combustion amount per unit time is obtained from the relationship of the PM combustion speed corresponding to the exhaust gas temperature that has been grasped in advance. PM2 is calculated by integrating this over the execution period of manual PM regeneration processing or automatic PM regeneration processing.

Then, the ECU 40 uses the PM emission amount PM1 calculated in step S401 and the PM combustion amount PM2 calculated in step S402, and the following equation M = M + PM1-PM2 (1)
From this, the amount of PM currently accumulated in the DPF 60, that is, the PM accumulation amount M is calculated (step S403). That is, in the subroutine processing, the PM amount in the DPF 60 is added to or subtracted from the PM accumulation amount M at the time of the previous processing by adding and subtracting the PM emission amount PM1 and the combustion amount PM2 generated between the execution time of the previous processing and the present time. A change amount of the accumulation amount is obtained, and a current PM accumulation amount M is calculated.

  Returning to FIG. 4 again, the ECU 40 calculates the amount of oil evaporation (step S302). Specifically, the ECU 40 detects the engine speed, and calculates the oil evaporation amount according to a pre-mapped engine speed-fuel injection amount command value-oil evaporation amount correspondence map. The map is defined in advance by an experimental, theoretical, or simulation technique. Typically, as the engine speed increases, the temperature of the engine 2 rises and the oil evaporation amount increases. On the other hand, as the engine speed decreases, the temperature of the engine 2 also decreases and the oil evaporation amount decreases. By mapping based on such a principle, an appropriate oil evaporation amount can be calculated in step S302.

  Subsequently, the ECU 40 calculates an oil dilution expected value F ′, which is an expected value of the oil dilution F (step S303). Here, the calculation method of the oil dilution expected value F ′ will be specifically described with reference to FIGS. 6 and 7. FIG. 6 is a graph showing time-series changes in various control signals, PM accumulation amount M, and oil dilution degree F when the automatic PM regeneration process is performed in the exhaust gas purification apparatus according to the first embodiment. FIG. 7 is a graph showing time-series changes in various control signals, PM accumulation amount M, and oil dilution degree F when manual PM regeneration processing is performed as PM regeneration processing in the exhaust gas purification apparatus according to the first embodiment. It is.

  FIG. 6A is a graph showing the input / output timing of the control signal Sa for the ECU 40 to execute the automatic PM regeneration process. The ECU 40 executes the automatic PM regeneration process by setting the control signal Sa to HIGH during the period of T1 ≦ T ≦ T2. In the period of T0 ≦ T <T1 and T2 <T, the control signal Sa is set to LOW, and the automatic PM regeneration process is not executed. That is, the ECU 40 starts the automatic PM regeneration process by setting the control signal Sa to HIGH when the time T reaches T1, and automatically sets the control signal Sa to Low when the time T reaches T2. The PM regeneration process is terminated.

  FIG. 6B is a graph showing a time-series change in the PM accumulation amount M. FIG. In T0 ≦ T <T1, since the PM regeneration process is not performed, the PM deposition amount M increases with the passage of time. Since the automatic PM regeneration process starts when the time T reaches T1, the PM deposition amount M decreases with the passage of time in the period of T1 ≦ T ≦ T2. And in the period of T2 <T, since the PM regeneration process is not performed as in the period of T0 ≦ T <T1, the PM deposition amount M increases with the passage of time.

  FIG. 6C is a graph showing the time series change of the oil dilution degree F. FIG. Before the automatic PM regeneration process is started (T0 ≦ T <T1), the PM regeneration process is not executed, and therefore, oil dilution due to fuel post-injection does not occur. Therefore, the oil dilution F0 at the time T0 decreases to F1 with the passage of time due to the evaporation of the fuel in the oil due to the heat generated by the engine 2. In the period of T1 ≦ T ≦ T2, the oil dilution proceeds by the post-injection of fuel performed in the automatic PM regeneration process, and the oil dilution F increases from F1 to F2. Since the post-injection is no longer performed in the period of T2 <T, the oil dilution F decreases with time as in the period of T0 ≦ T1 <T. Then, an oil dilution expected value F ′ at a time point T3 (a certain time has elapsed from the end of the regeneration process T2) is calculated.

  Next, FIGS. 7A and 7B show the input timing of the control signal Sm for the ECU 40 to execute the manual PM regeneration process, and the input timing of the control signal Sn for instructing the driver to start the manual PM regeneration process. (That is, a timing at which the driver turns on and off a button for starting manual PM regeneration processing (not shown)). The ECU 40 sets the control signal Sm to HIGH during a period of T1 ≦ T ≦ T2, thereby enabling the manual PM regeneration process (specifically, the manual PM regeneration process is performed at the timing of T = T1). Notify the driver by turning on a warning light to prompt). Then, the manual PM regeneration process is executed by the driver instructing the ECU 40 to start the manual PM regeneration process at the timing of T = T1 ′. At T = T2, the manual PM regeneration process is completed. Thus, the manual PM regeneration process is executed in T1 ′ ≦ T ≦ T2, and the automatic PM regeneration process is not executed in the period of T0 ≦ T <T1 ′ and T2 <T.

  FIG. 7C is a graph showing the time-series change of the PM accumulation amount M when the manual PM regeneration process is executed. In T0 ≦ T <T1 ′, since PM regeneration processing is not performed, PM increases as time elapses. Since the manual PM regeneration process starts when the time T reaches T1 ′, the PM deposition amount M decreases with the passage of time during the period of T1 ′ ≦ T ≦ T2. And in the period of T2 <T, the PM regeneration process is not performed as in the period of T0 ≦ T <T1 ′. Therefore, the PM deposition amount M increases with the passage of time.

  FIG. 7D is a graph showing the time series change of the oil dilution F when the manual PM regeneration process is executed. Before the manual PM regeneration process is started (T0 ≦ T <T1 ′), since the PM regeneration process is not executed, oil dilution due to fuel post-injection does not occur. Therefore, the oil dilution F0 at the time T0 decreases to F1 with the passage of time due to the evaporation of the fuel in the oil due to the heat generated by the engine 2. In the period of T1 ′ ≦ T ≦ T2, the oil dilution proceeds by the fuel post-injection performed in the automatic PM regeneration process. Therefore, the oil dilution degree F increases from F1 ′ to F2 during the period. Since the post-injection is no longer performed in the period of T2 <T, the oil dilution F decreases with the passage of time as in the period of T0 ≦ T1 ′ <T.

  The expected oil dilution value F ′ is calculated based on the past operating state data history and the actual data on the regeneration process stored in the storage means 95 before the timing (T = T1) for starting the PM regeneration process. Is done. For example, refer to past data that was in the same or similar driving conditions as the conditions where the vehicle was placed before starting the PM regeneration process, and expect to behave in the same way as the transition of PM deposition at that time Thus, the next filter regeneration timing T3 may be calculated. Furthermore, the predicted oil dilution value F ′ at the next filter regeneration processing timing T3 may be calculated by assuming that the same behavior as the transition of the oil dilution after the start of the PM regeneration process at that time is performed.

  In addition, when fuel is post-injected to the engine 2 in the PM regeneration process, the fuel adhering to the wall surface of the cylinder constituting the engine 2 reaches the oil pan through the wall surface of the cylinder and proceeds with oil dilution. Let Therefore, when the fuel injection amount increases, the oil dilution F also increases (that is, the oil dilution F typically depends on the fuel injection amount). Further, when the load on the engine 2 increases, the number of revolutions of the engine 2 increases and the temperature of the engine 2 increases, so that the oil dilution F also decreases as the amount of oil evaporation increases. On the other hand, when the load on the engine 2 decreases, the rotational speed of the engine 2 decreases and the temperature of the engine 2 also decreases, so that the amount of oil evaporation decreases and the oil dilution F also increases. According to such characteristics, it is also possible to perform mapping of the engine speed and the oil dilution F, and calculate the oil dilution expected value F ′ based on the map.

  Returning to FIG. 4 again, the ECU 40 determines whether or not the predicted oil dilution value F ′ calculated in step S303 is greater than the threshold value Fm (step S304). Here, the threshold value Fm is a threshold value for deciding whether to select manual PM regeneration processing or automatic PM regeneration processing in executing the PM regeneration processing, and has been experimentally, theoretically, or simulated in advance. It is good to prescribe. The threshold value Fm is an example of the threshold value of the first embodiment in the oil dilution degree expected value determination means 80.

  Here, referring to FIG. 6 (c) and FIG. 7 (d), focusing on the behavior of the oil dilution F after the completion of the automatic PM regeneration process and the manual PM regeneration process, the oil dilution F of the manual PM regeneration process The increase amount is smaller than the increase amount of the oil dilution F in the automatic PM regeneration process. As described above, this is because the manual PM regeneration process has a smaller oil dilution than the automatic PM regeneration process. In this way, the selection means 90 controls to switch between the manual PM regeneration process and the automatic PM regeneration process by considering the progress of the oil dilution degree of each of the manual PM regeneration process and the automatic PM regeneration process. In this embodiment, when the oil dilution degree predicted value F ′ is large, if the automatic PM regeneration means is used, the oil dilution degree deteriorates and it is considered undesirable. If the process is selected and the estimated value of oil dilution F ′ is considered to be within an allowable range, it can be executed while the vehicle is traveling although the degree of progress of the oil dilution is large (that is, the driver stops the vehicle). The automatic PM regeneration process is selected, which does not require a complicated process such as setting the idling state.

  Subsequently, when the oil dilution predicted value F ′ is larger than the threshold value Fm by the selection means 90 of the ECU 40 (step S304: YES), the manual PM regeneration process is selected as the PM regeneration process. In this case, the ECU 40 further determines whether or not the PM accumulation amount M calculated in step S301 is larger than the threshold value M1 (step S305). Here, the threshold value M1 is a threshold value for determining whether or not it is necessary to execute the manual PM regeneration process. Typically, if the manual PM regeneration process is not performed, whether or not the engine 2 or the like is adversely affected. This threshold is set in advance.

  If the result of determination in step S305 is that the PM accumulation amount M is greater than the threshold value M1 (step S305: YES), manual PM regeneration processing is executed (step S306). After completion of the manual PM regeneration process, the ECU 40 predicts the amount of fuel mixed in the oil by the operation of the exhaust purification device this time, and calculates the oil dilution. Further, the estimated fuel mixing amount is used when estimating the oil dilution degree in the next manual PM regeneration process. On the other hand, when the PM accumulation amount M is equal to or less than the threshold value M1 (step S305: NO), the ECU 40 determines that the manual PM regeneration process is unnecessary and returns the process without performing the PM regeneration (RETURN).

  When the oil dilution expected value F ′ is equal to or less than the threshold value F1 (step S304: NO), the automatic PM regeneration process is selected as the PM regeneration process by the selection unit 90 of the ECU 40. In this case, the ECU 40 further determines whether or not the PM accumulation amount M calculated in step S301 is larger than the threshold value M2 (step S308). Here, the threshold value M2 is a threshold value for determining whether or not it is necessary to execute the automatic PM regeneration process. Typically, if the automatic PM regeneration process is not performed, whether or not the engine 2 or the like is adversely affected. This threshold is set in advance.

  If the result of determination in step S308 is that the PM accumulation amount M is greater than the threshold value M2 (step S308: YES), automatic PM regeneration processing is executed (step S309). After the completion of the automatic PM regeneration process, the ECU 40 predicts the amount of fuel mixed in the oil by the operation of the exhaust purification device this time, and calculates the oil dilution. Further, the estimated fuel mixing amount is used when estimating the oil dilution degree in the next automatic PM regeneration process. On the other hand, when the PM accumulation amount M is equal to or less than the threshold value M2 (step S308: NO), the ECU 40 determines that the automatic PM regeneration process is unnecessary and returns the process without performing the PM regeneration (RETURN).

(Second embodiment)
In the first embodiment described above, whether the manual PM regeneration process or the automatic PM regeneration process should be performed as the PM regeneration process is determined based on the oil dilution degree expected value F ′. On the other hand, the second embodiment is characterized in that the determination is made based on the frequency D existing in the dilution progress region calculated based on the operating state of the engine 2. In other words, in the second embodiment, the frequency D existing in the dilution progress region based on the past operating state data stored in the storage means 95 is calculated by the oil dilution predicted value calculation means 70. Judgment is made using the predicted value of dilution.
In addition, about 2nd Example, suppose that description is abbreviate | omitted suitably about the location which is common in 1st Example.

  First, the operation of the exhaust emission control system according to the second embodiment will be described with reference to FIG. FIG. 8 is a flowchart showing the operation of the exhaust gas purification apparatus according to this embodiment.

  The ECU 40 calculates the PM accumulation amount M (step S501) in the same manner as in the first embodiment described above (see step S301 in FIG. 4).

  Subsequently, the ECU calculates a dilution progress in-region frequency D indicating the frequency at which the operating state of the engine 2 is in the oil dilution progress region (step S502). Specifically, the frequency D in the dilution progress region is calculated by executing a subroutine process shown in FIG. FIG. 9 is a flowchart of a subroutine for calculating the frequency D within the dilution progress region.

First, the ECU 40 sets a parameter t for determining whether or not it is time to perform the calculation of the frequency D in the dilution progress region as follows: t = t + ΔT (2)
(Step S601). Here, ΔT is a time period in which the subroutine process shown in the flowchart of FIG. 9 is executed. Then, the ECU 40 determines whether or not the engine 2 is in the oil dilution progress region by calculating the current operating state of the engine 2 (step S602). This determination can be made by detecting the engine speed and engine torque (fuel injection amount command value).

  Here, FIG. 10 is a graph showing the relationship between the engine speed of the engine 2 -engine torque-oil dilution progress in the embodiment. The horizontal axis in FIG. 10 indicates the engine speed, and the vertical axis indicates the fuel injection amount of the engine 2 corresponding to the engine torque. FIG. 10 shows that the oil dilution progress of the engine 2 decreases as the engine speed and the fuel injection amount increase.

  In FIG. 10, the oil dilution progress region is defined as a region on the lower left side (shaded portion) from the boundary line A. The boundary line A is a boundary line that defines the oil dilution degree progress region. The ECU 40 can determine whether or not the operating state of the engine 2 is within the oil dilution progress region on the map shown in FIG. 10 by acquiring the engine speed and the fuel injection amount.

Returning to FIG. 9 again, the ECU 40 sets the parameter E having a time unit as follows: E = E + ΔT (3)
(Step S603).

Subsequently, the ECU 40 determines whether or not t calculated by the equation (2) is equal to or greater than T, which is a cycle for calculating the dilution progress region frequency D (step S604). If t ≧ T (step S604: YES), the dilution progress region frequency D is expressed by the following equation: D = E / T (4)
(Step S605). Supplementally, as is apparent from the equation (4), the frequency D in the dilution progress region is the period E in which the oil dilution of the engine 2 is within the oil dilution progress region shown in FIG. As a percentage of Then, the ECU 40 initializes the parameter E and ends the process (step S606).

  Returning to FIG. 8 again, it is determined whether or not the frequency D in the dilution progress region calculated in step S502 is larger than the threshold value D1 (step S503). Here, the threshold value D1 is an example of the threshold value of the second embodiment in the oil dilution degree expected value determination means 80. When the frequency D in the dilution progress area is greater than D1 (step S503: YES), the selection unit 90 selects the manual PM regeneration process as the PM regeneration process. On the other hand, when the dilution progress frequency D is equal to or less than the threshold value D1 (step S503: NO), the selecting unit 90 selects the automatic PM regeneration process as the PM regeneration process. Since the subsequent processing is the same as in the first embodiment, the same reference numerals are given here, and detailed description thereof is omitted.

As described above, according to the second embodiment, the selection unit 90 switches between the first regeneration unit and the second regeneration unit on the basis of the magnitude of the predicted value of the oil dilution, so that the oil It is possible to achieve both suppression of the progress of dilution and improvement of the fuel consumption rate.
The predicted value of the oil dilution is calculated as an estimated value based on past performance data of the internal combustion engine (for example, past operating state data of a vehicle in which the internal combustion engine is mounted), so that the appropriate value in accordance with the driving situation of the internal combustion engine Switching control is possible.
In particular, this is a case where the operation state of the internal combustion engine shows a complicated change from moment to moment by performing switching control based on whether or not the ratio that the operation state is in the low rotation-low torque region is larger than the threshold value D1. Also, appropriate switching control can be realized.

2 Engine 6 Intake manifold 8 Intake passage 10 Intake manifold 12 Exhaust passage 40 ECU
60 DPF
70 Oil dilution expected value calculation means 80 Oil dilution expectation value determination means 90 Selection means 95 Storage means

Claims (6)

An exhaust purification device for an internal combustion engine comprising a filter that collects particulate matter contained in the exhaust of the internal combustion engine,
Storage means for storing past operating conditions of the internal combustion engine and performance data relating to filter regeneration processing;
An oil dilution expected value calculating means for calculating an oil dilution expected value that is an expected value of the oil dilution in the internal combustion engine using past data stored in the storage means;
An oil dilution expected value determination means for determining whether or not the calculated oil dilution expected value is larger than a predetermined threshold;
A first regeneration means capable of regenerating the filter by burning the collected particulate matter;
A second regenerating unit that is capable of regenerating the filter by burning the collected particulate matter, wherein the oil dilution amount is lower than that of the first regenerating unit and the fuel consumption rate is higher; ,
When it is determined by the oil dilution predicted value determination means that the calculated oil dilution predicted value is less than or equal to the threshold, the first regeneration means is selected from the two regeneration means, and the filter When the predicted oil dilution value is determined to be greater than the threshold by the oil dilution predicted value determination unit, the second regeneration unit is selected from the two regeneration units. An exhaust emission control device for an internal combustion engine, comprising: selection means for controlling the first regeneration means and the second regeneration means so as to regenerate the filter.   The oil dilution prediction value calculation means predicts the next filter regeneration processing timing before starting the filter regeneration processing, and based on the past data stored in the storage means the oil dilution at that time. 2. The exhaust gas purifying apparatus for an internal combustion engine according to claim 1, wherein the predicted value of oil dilution degree determination means predicts and determines the magnitude of the threshold value using the predicted oil dilution degree.   The actual data relating to the filter regeneration process stored in the storage means includes the oil dilution amount by the first regeneration means, the oil dilution amount by the second regeneration means, and the time until the first regeneration means is performed. 3. An exhaust emission control device for an internal combustion engine according to claim 2, wherein the exhaust gas purifying device includes an interval, a time interval until execution of the second regeneration means, and data on the amount of oil evaporation, and is stored in a map.   The oil dilution expected value calculation means is an oil dilution progress region determined by the load and rotation speed of the internal combustion engine within a predetermined period of time based on the operation state data stored in the storage means. 2. The internal combustion engine according to claim 1, wherein a predetermined ratio is calculated, and the dilution degree expected value determination means determines the magnitude of the threshold value using a ratio within the calculated oil dilution progress region. Exhaust purification equipment.   5. The filter according to claim 1, wherein the first regeneration unit and the second regeneration unit regenerate the filter by post-injecting fuel at different timings. 6. An exhaust purification device for an internal combustion engine.   The exhaust purification of an internal combustion engine according to any one of claims 1 to 5, wherein the first regeneration means is an automatic PM regeneration process, and the second regeneration means is a manual PM regeneration process. apparatus.

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