JP4165082B2 - Exhaust purification device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust emission control device for processing exhaust particulates of, for example, a diesel engine.
[0002]
[Prior art]
In order to process the exhaust particulates discharged from the diesel engine, a particulate filter is arranged in the exhaust system, and when the collected amount of particulates reaches a certain value, post injection, which is the second injection following the main injection, is performed. JP-A-2000-161044 proposes to regenerate the filter by burning the particulates by increasing the filter temperature.
[0003]
[Problems to be solved by the invention]
By the way, if the post-injection amount for increasing the temperature of the filter is small, most of the post-injected fuel does not change to heat for increasing the exhaust gas temperature to generate torque. When the amount increases, a part of the combustion heat changes to torque, and a torque step occurs before and after the post injection, resulting in poor operability.
[0004]
For this reason, the above-described conventional device is provided with an intake throttle device (or an exhaust throttle device), and corrects the post injection amount so that the exhaust temperature matches the target temperature (the temperature optimal for the combustion of the particulates). Thus, the increase in torque is canceled by operating the intake throttle device, so that the fluctuation of the torque does not occur before and after the post injection while the filter is regenerated by the post injection.
[0005]
However, post-injection, which consumes fuel, is an element that tends to directly affect fuel consumption in the first place, and operating the intake throttle device to offset the increase in torque caused by post-injection also deteriorates fuel consumption. According to the above-described conventional device in which the operation of the intake throttle device is simultaneously performed, the fuel consumption during the filter regeneration process is significantly deteriorated.
[0006]
Further, in the conventional device, control of the exhaust temperature to the target temperature is performed by the post injection amount, and the torque fluctuation is eliminated by the operation of the intake throttle device (the fuel supply device that performs post injection and the intake throttle device). ) And control parameters (exhaust temperature and engine torque) are independent, but any one control parameter affects the remaining control parameters, so it takes time for the exhaust temperature and engine torque to converge to the target. There is also a problem.
[0007]
In view of this, in the present invention, only one fuel supply device is controlled, and the two control parameters of the exhaust temperature and the engine torque are simultaneously controlled by using only this fuel supply device, thereby deteriorating the fuel consumption during the filter regeneration process. The purpose is to reduce the time until the exhaust temperature and the engine torque converge to the target.
[0008]
[Means for Solving the Problems]
According to a first aspect of the present invention, in an exhaust emission control device for an engine having a filter for collecting particulates in an exhaust passage, a post-injection amount basic value or a post-injection timing basic value is set according to the engine speed and load. The post-injection amount / time setting means to be set and the regeneration processing for regenerating the filter by increasing the exhaust temperature by post-injection using the post-injection amount basic value or the post-injection time basic value when the filter regeneration time comes Means, torque fluctuation determination means for determining whether or not there is a fluctuation in engine torque during the filter regeneration process, and whether or not the exhaust temperature is further deviated from the target temperature when there is a fluctuation in engine torque based on the determination result From the judgment means and the judgment result If the engine output shaft angular velocity change is large outside the allowable value and the exhaust temperature is high outside the target temperature, the engine output shaft angular velocity change is below the allowable value and the exhaust temperature is below the target temperature. And when it ’s too low While suppressing fluctuations in engine torque at the same time The post-injection amount basic value so that the exhaust temperature falls within the target temperature only The Similarly, when the amount of change in the angular velocity of the engine output shaft is large outside the allowable value and the exhaust temperature is low outside the target temperature, the engine temperature fluctuation is suppressed and the exhaust temperature falls within the target temperature at the same time. Only the basic value of the post injection timing A post-injection correction unit that corrects the fuel and a fuel supply device that performs post-injection corrected by the post-injection correction unit.
[0009]
According to an eleventh aspect of the present invention, in the engine exhaust gas purification apparatus provided with a filter for collecting particulates in the exhaust passage, a post injection basic value or a post injection timing basic value is set according to the engine speed and load. Post-injection amount / time setting means for performing regeneration processing means for increasing the exhaust temperature by post-injection using the post-injection amount basic value or the post-injection time basic value and performing filter regeneration processing when the filter regeneration time comes And torque fluctuation determining means for determining whether or not there is a fluctuation in engine torque during the regeneration process of the filter, and determining whether or not the exhaust temperature is further deviated from the target temperature when there is a fluctuation in engine torque based on the determination result From the judgment means and this judgment result If the engine output shaft angular velocity change is large outside the allowable value and the exhaust temperature is high outside the target temperature, the engine output shaft angular velocity change is below the allowable value and the exhaust temperature is below the target temperature. And when it ’s too low While suppressing fluctuations in engine torque at the same time The post-injection amount basic value so that the exhaust temperature falls within the target temperature only The Similarly, if the amount of change in the angular speed of the engine output shaft is large outside the allowable value and the exhaust temperature is low outside the target temperature based on the determination result, fluctuations in the engine torque are suppressed and at the same time the exhaust temperature falls within the target temperature. Only the basic value of the post-injection timing is corrected, and the engine torque fluctuation is suppressed when the change amount of the angular speed of the engine output shaft falls below the allowable value and the exhaust temperature is higher than the target temperature. At the same time, the post-injection amount basic value is set so that the exhaust temperature falls within the target temperature. And post / main injection correction means for correcting the main injection, and a fuel supply device for performing post injection and main injection corrected by the post / main injection correction means.
[0010]
【The invention's effect】
After starting the filter playback process If the engine output shaft angular velocity change is larger than the allowable value and the exhaust temperature is higher than the target temperature, the engine output shaft angular velocity change is less than the allowable value and the exhaust temperature is less than the target temperature. And when it ’s too low While suppressing fluctuations in engine torque at the same time Claim 1 so that the exhaust temperature falls within the target temperature. , 11 According to the invention described in (4), the post-injection amount basic value only The The engine output shaft angular velocity change amount is larger than a permissible value and the exhaust temperature is lower than the target temperature, and the exhaust temperature is kept at the target temperature while suppressing fluctuations in engine torque. According to the invention described in No. 11, only the basic value of the post injection timing Therefore, when post-injection for regeneration processing is performed, fluctuations in engine torque due to manufacturing variations and deterioration over time in the engine body and fuel injection device and deviation of the exhaust temperature from the target temperature may occur. Even in such a case, the exhaust temperature can be quickly converged to the target temperature while suppressing torque fluctuations. The Filter regeneration processing can be performed accurately without impeding drivability.
[0011]
In this case, the control target is basically a fuel supply device that performs post-injection and main injection. Since this fuel supply device is used to control two control parameters of exhaust temperature and engine torque at the same time, filter regeneration processing is performed. It is possible to prevent the deterioration of fuel consumption and to shorten the time until the exhaust temperature and the engine torque are converged to the target.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
[0013]
First, in FIG. 1, 1 is a diesel engine, 2 is an intake passage, and 3 is an exhaust passage. A filter 4 that collects particulates in the exhaust is installed in the exhaust passage 3. When the amount of particulates collected by the filter 4 reaches a predetermined value, the exhaust gas temperature is raised and the particulates are burned and removed.
[0014]
In order to detect the pressure loss of the filter 4 (pressure difference between the upstream and downstream of the filter 4), a differential pressure sensor 12 is provided in the differential pressure detection passage that bypasses the filter 4.
[0015]
The pressure loss of the filter 4 detected by the differential pressure sensor 12 includes the engine rotation speed from the crank angle sensor 13, the accelerator opening from the accelerator sensor 14 (depressing amount of the accelerator pedal), and the intake air flow rate from the air flow meter 15. At the same time, the controller 11 mainly composed of a microprocessor performs the regeneration processing of the filter 4 based on these.
[0016]
That is, before the regeneration process, the pressure loss ΔP detected by the differential pressure sensor 12 is compared with the regeneration start determination value to determine whether the regeneration start time has come, and when the regeneration start time has come, the exhaust temperature is raised. The regeneration process of all the filters 4 is started, and thereafter, the pressure loss ΔP detected by the differential pressure sensor 12 is compared with the regeneration end determination value to determine whether or not the regeneration end time has come, and the regeneration end time is reached. The playback process is terminated.
[0017]
The regeneration process of the filter 4 is basically a process of raising the exhaust gas temperature to a target temperature (a temperature optimal for burning particulates). In this case, since the exhaust temperature varies depending on the engine load and the rotational speed, as shown in FIG. 2, the entire operation region is roughly divided into four, and the following is performed according to the exhaust temperature in each of the divided operation regions. Perform playback processing.
[0018]
Region R1: This is a region near the full load. In this region, the exhaust gas temperature becomes the target temperature, and the regeneration is performed by burning the particulates naturally without performing the regeneration process. Therefore, the regeneration process is not performed.
[0019]
Region R2: In the regions R2 to R4 on the lower load side than the region R1, the exhaust gas temperature does not become the target temperature, so it is necessary to forcibly perform the regeneration process. Therefore, in the region R2, first, the injection timing (main injection timing) of the fuel injected from the fuel injection device (for example, the common rail type injection device including the supply pump 6, the common rail 7, and the injector 8) is delayed from the normal time (before the regeneration process). The reproduction process is performed. The exhaust gas temperature rises to the target temperature by retarding the main injection timing.
[0020]
Region R3: This is a region where the exhaust temperature cannot be set to the target temperature depending on the delay of the main injection timing, and is regenerated by performing post injection (injecting in the expansion stroke after the main injection) instead of the delay of the main injection timing. Process. The exhaust temperature rises to the target temperature by post injection in the expansion stroke.
[0021]
Region R4: a low load region where the exhaust gas temperature is originally low. In this region, the exhaust gas temperature cannot be raised to the target temperature by any of the above methods, so the regeneration process is not performed.
[0022]
If the post-injection amount in the region R3 is small, most of the post-injected fuel does not reach the torque for generating heat due to the rise in exhaust temperature, but the post-injection amount is large. In this case, a part of the torque changes to torque, so that the engine torque fluctuates before and after the regeneration process, which is not preferable in terms of drivability. For this reason, the post-injection amount in the region R3, the post-injection time, so that the engine torque does not vary before and after the regeneration Period And the main injection amount is adjusted. For example, the PV diagram differs depending on the presence or absence of post-injection, as shown in FIG. 3. In this case, the post-injection amount and post-injection time are set so that the illustrated areas As and Ap are equal. Period In addition, by adjusting the main injection amount, it is possible to prevent a difference in engine torque before and after the regeneration process.
[0023]
Thus, the regeneration process is performed by performing the post injection in the region R3, and the post injection amount, the post injection timing, the main injection amount, and the main injection amount are set so that the engine torque is equal before and after the regeneration process. However, there are individual differences (compression ratio, injector 8 injection characteristics, common rail pressure, etc. vary) in the engine body and fuel injection system, and these deteriorate over time. Avoid not only engine torque fluctuations, such as engine torque decreasing immediately after starting regeneration, but also increasing or decreasing exhaust temperature outside the target temperature. Therefore, in this embodiment, it is determined whether or not the engine torque fluctuates after the start of the regeneration process with post injection. See if further or exhaust temperature is out of the target temperature when the click changes occur. Based on these results, in the following four cases (1) to (4), in principle, post-injection is controlled (in some cases, main injection is also controlled), and torque fluctuations before and after the regeneration process are controlled. The exhaust temperature is adjusted to be within the target temperature while suppressing the above.
[0024]
(1) If engine torque is excessive and torque fluctuation occurs and the exhaust temperature is too high,
(2) If engine torque is excessive and torque fluctuation occurs and the exhaust temperature is too low,
(3) If the engine torque is insufficient and torque fluctuation occurs and the exhaust temperature is too high,
(4) If the engine torque is insufficient and torque fluctuation occurs and the exhaust temperature is too low,
Next, these control contents performed by the controller 11 will be described according to the following flowchart.
[0025]
4 and 5 are for setting a correction flag newly introduced in the present invention, and are repeatedly executed at predetermined time intervals (for example, every 10 ms).
[0026]
Here, the correction flag is a post injection amount reduction flag 1, a post injection amount reduction flag 2, which will be described later, Post injection amount increase flag, It is a generic term for five flags: a post injection timing retard flag and a main injection amount increase flag.
[0027]
In step 1, the angular velocity ω of the crankshaft (engine output shaft) is calculated. The angular velocity ω is calculated by measuring a time Tint required for a predetermined crank angle section provided during an explosion stroke of each cylinder using a signal from the crank angle sensor 13, for example.
ω = predetermined crank angle section / Tint (1)
The crankshaft angular velocity ω may be calculated by the following formula.
[0028]
Steps 2, 3, and 4 are in the post-injection region (hereinafter simply referred to as “post-injection region”) when the regeneration processing start timing is reached, and are also in the post-injection region during the subsequent regeneration processing. It is a part that determines whether or not. That is, the operating conditions determined from the value of the current regeneration process flag in step 2, the value of the previous regeneration flag in step 4, and the engine speed Ne and the fuel injection amount basic value Qf1 in step 3 are shown in FIG. See if it is in R3 (ie post-injection zone).
[0029]
Here, the regeneration processing flag becomes 1 when the pressure loss ΔP of the filter 4 becomes large and this pressure loss ΔP becomes larger than the regeneration start determination value which is the pressure loss at the time of regeneration start, and then the pressure loss ΔP is regenerated. This flag returns to zero when it becomes smaller than the regeneration end determination value that is the pressure loss at the end, and is zero when the pressure loss ΔP is equal to or less than the regeneration start determination value (see the uppermost stage in FIG. 16).
[0030]
If the current regeneration processing flag = 1 and the previous regeneration flag = 0 (when the current regeneration processing flag is 1 for the first time) and the post-injection region, the process proceeds to step 5, and the angular velocity ω at that time is stored in the memory ω0. Transfer. As a result, the angular speed of the crankshaft at the start of the reproduction process is taken into the value of the memory ω0.
[0031]
If the current regeneration processing flag = 1 and the previous regeneration flag = 1 (during regeneration processing) and the post-injection region, the change amount Δω of the angular velocity from the regeneration processing start timing in step 6 is
Δω = ω−ω0 (2)
Calculate with the following formula.
[0032]
Post-injection is performed at the start of the regeneration process. In this case, due to individual differences in the engine body and fuel injectors and deterioration over time, the engine torque increases and the angular speed ω increases when the post-injection amount is too large. When the amount Δω increases with a positive value and the post-injection amount is too small, the engine torque decreases and the angular velocity ω decreases, so the angular velocity change amount Δω increases with a negative value.
[0033]
Therefore, in step 7, the angular velocity change amount Δω is compared with the allowable value α (α is a positive constant value) and −α, and when Δω is within the allowable range (−α ≦ Δω ≦ α), the fluctuation of the engine torque Since there is no need to perform control for suppressing the current process, the current process is terminated.
[0034]
On the other hand, when Δω> α (the angular velocity change amount is larger than the allowable value) or Δω <−α (the angular velocity change amount falls below the allowable value), the angular velocity change amount is within the allowable range. If it is determined that the engine torque fluctuation amount is outside the allowable range, the process proceeds to FIG.
[0035]
In step 8 of FIG. 5, the correction flag set flag is viewed. The correction flag set flag is a flag that becomes 1 after checking whether or not correction of the post injection amount, post injection timing, or main injection amount is necessary or unnecessary as described later (see step 20). Therefore, since the regeneration process flag = 1 and the angular velocity change amount Δω is out of the allowable range in the post-injection region, the process proceeds to step 8 at first. Since the correction flag set flag = 0, the process proceeds to step 9 and subsequent steps.
[0036]
In step 9, the filter upstream temperature T1 (exhaust temperature) detected by the temperature sensor 16 is read.
[0037]
In steps 10, 11, 12, 13, 14, and 15, the following changes (1) to (5) are made by comparing the angular velocity change amount Δω and the allowable values α and −α, and the filter upstream temperature T1 and the target temperature. In the cases (1) to (4), flags are set as follows in steps 16, 17, 18, and 19 in accordance with the determination results. However, the target temperature here has an allowable range centered on a reference temperature Tm (for example, about 550 ° C.), and Tm + β (β is a positive constant value) is a target temperature upper limit, and Tm−β is a target temperature lower limit. During this time, all are at the target temperature, and as long as the upstream temperature of the filter is at this target temperature, particulate combustion is optimally performed.
[0038]
(1) When Δω is larger than α and T1 exceeds Tm + β:
This is the case when the engine torque is excessive and torque fluctuation occurs and the exhaust temperature is too high. At this time, the routine proceeds from Steps 10 and 11 to Step 16 to set the post injection amount reduction flag 1 = 1.
[0039]
Here, the post injection amount reduction flag 1 instructs to reduce the post injection amount when the post injection amount reduction flag 1 = 1. When the post injection amount is reduced from the broken line to the solid line as shown in FIG. 6A by this instruction, the exhaust temperature is lowered and the engine torque is also lowered.
[0040]
(2) When Δω is larger than α and T1 is lower than Tm−β:
This is the case when the engine torque is excessive and torque fluctuations occur and the exhaust temperature is too low. At this time, the routine proceeds from Steps 10, 11 and 12 to Step 17 to set the post injection timing retard flag = 1.
[0041]
This post-injection timing retard flag indicates the retard of the post-injection timing when the post-injection timing retard flag = 1. When the post injection timing is retarded from the broken line to the solid line as shown in FIG. 6 (b) by this instruction, the rate of conversion to engine torque in the combustion heat by the post injection in the expansion stroke is reduced and the exhaust gas is exhausted. Since the heat released to the passage 3 increases, the exhaust temperature rises while the engine torque decreases.
[0042]
(3) When Δω is smaller than −α and T1 exceeds Tm + β:
This is the case when engine torque is insufficient and torque fluctuations occur and the exhaust temperature is too high. At this time, the routine proceeds from steps 10, 13, and 14 to step 18, where the main injection amount increase flag = 1 and the post injection amount decrease flag 2 = 1.
[0043]
The main injection amount increase flag and the post injection amount decrease flag 2 indicate an increase in the main injection amount and a decrease in the post injection amount when both of these flags are 1. When the main injection amount is increased from the broken line to the solid line and the post injection amount is decreased as shown in FIG. 6C by this instruction, the engine torque increases as the main injection amount increases, and the post injection amount Decreasing the exhaust temperature decreases.
[0044]
(4) When Δω is smaller than −α and T1 is lower than Tm−β:
This is the case when the engine torque is insufficient and torque fluctuation occurs and the exhaust temperature is too low. At this time, the routine proceeds from Steps 10, 13, 14, and 15 to Step 19 to set the post injection amount increase flag = 1.
[0045]
The post injection amount increase flag instructs to increase the post injection amount when the post injection amount increase flag = 1. When the post injection amount is increased by this instruction as shown in FIG. 6 (d), the rate at which the combustion heat by the post injection in the expansion stroke is converted into the engine torque increases, so that the engine torque increases and The exhaust temperature also rises.
[0046]
(5) Otherwise, that is, do nothing in the following cases.
[0047]
1. Δω is larger than α which is the upper limit of allowable value, but T1 is within the target temperature.
If
2. Δω is smaller than the lower limit of the allowable value -α is small but T1 falls within the target temperature
If
This completes the setting of the correction flag. In step 20, the correction flag set flag = 1 is set. From this correction flag set flag = 1, it is not possible to proceed to step 9 and thereafter from the next time. That is, the correction flag is set to 1 only once when a torque fluctuation occurs after the start of the regeneration process.
[0048]
Next, each calculation method of the post injection amount, the post injection timing, and the main injection amount will be specifically described.
[0049]
First, FIG. 7, FIG. 8, and FIG. 9 are for calculating the post-injection amount QP, and are executed each time a crank angle reference position signal (abbreviated as Ref. In the figure) is input.
[0050]
At steps 31 and 32 in FIG. When the regeneration process flag = 0, or even when the regeneration process flag = 1, it is not necessary to perform the post-injection when it is not in the post-injection amount range, the routine proceeds to step 66 and the post-injection amount QP = 0.
[0051]
Since it is necessary to perform post-injection when the regeneration processing flag = 1 and in the post-injection region, the process proceeds to step 33 and the post-injection amount is calculated.
[0052]
In step 33, the engine speed Ne, the main injection amount basic value Qf1, and the filter upstream temperature T1 are read. Here, the main injection amount basic value Qf1 is a fuel injection amount obtained by performing various corrections on the basic fuel injection amount Mqdrv determined according to the accelerator opening and the engine speed as described later (step 93 in FIG. 13). reference).
[0053]
In step 34, a post injection basic value QP0 is calculated by searching a map having the contents shown in FIG. 10 from the engine speed Ne and the main injection basic value Qf1. The basic value of the post-injection amount corresponds to the exhaust temperature that changes according to the operating conditions (Ne, Qf1), and increases as the load decreases as the exhaust temperature decreases. This is because the difference from the target temperature increases as the load decreases as the exhaust temperature decreases, and the post-injection amount must be increased accordingly. The optimum value is finally determined by matching.
[0054]
Step 35 in FIG. 7 and steps 36 and 37 in FIG. 8 look at the post injection amount decrease flag 1, the post injection amount decrease flag 2, and the post injection amount increase flag.
(1) When the post injection amount reduction flag 1 = 1
Proceeding to step 38 in FIG. 7, it is determined whether or not the filter upstream temperature T1 is outside the target temperature (indicated by “outside of allowable range” in the figure, the same in FIGS. 8, 11, and 13). Since T1 is higher than the target temperature upper limit Tm + β at the beginning when the post injection amount reduction flag 1 becomes 1 after the filter regeneration process is started, the routine proceeds to step 39, where the post injection amount correction value (reduction amount correction value) QPHOS1 (initial value) Is zero),
QPHOS1 = QPHOS1z + ΔQP1 (3)
However, QPHOS1z: the previous value of QPHOS1,
ΔQP1: increment,
It calculates by the formula of The post injection amount correction value QPHOS1 is a value that increases by ΔQP1 every calculation cycle.
[0055]
In step 40, the post injection amount correction value QPHOS1 is subtracted from the post injection basic value QP0, that is,
QP = QP0−QPHOS1 (4)
The final post-injection amount QP is calculated by the following formula. Equation (4) is an equation for reducing the post-injection amount.
[0056]
If the post injection amount QP is reduced when the post injection amount reduction flag 1 = 1 (when the engine torque is excessively generated and torque fluctuation occurs and the exhaust temperature is too high), the filter upstream temperature T1 decreases, and the engine torque is reduced accordingly. Therefore, if the reduction of the post injection amount QP is continued, the filter upstream temperature T1 eventually falls within the target temperature.
[0057]
At this time, it is assumed that the angular velocity change amount Δω is also within the allowable value α, so that the post injection amount reduction is completed, the process proceeds from step 38 in FIG. 7 to step 41 to set the post injection amount reduction flag 1 = 0 and then step 42. The value of the post injection amount correction value QPHOS1 is moved to the memory QPL1, and QPHOS1 = 0 is set in preparation for the next regeneration process. QPL1 is a decrease correction value for the post injection amount when the filter upstream temperature T1 falls within the target temperature.
[0058]
In step 43, the post injection basic value QP0 and the memory value are used.
QP = QP0−QPL1 (5)
The final post-injection amount QP is calculated by the following formula.
[0059]
Finally, in step 44, the post injection amount reduced flag 1 = 1 is set.
(2) When the post injection amount reduction flag 2 = 1
This is the same as in the case of the post injection amount reduction flag 1 = 1 in (1) above.
[0060]
Proceeding to step 45 in FIG. 8, it is determined whether or not the filter upstream temperature T1 is outside the target temperature. Since T1 is higher than the target temperature upper limit Tm + β when the post-injection amount reduction flag 2 becomes 1 after the filter regeneration process is started, the routine proceeds to step 46, and the post-injection amount correction value (reduction amount correction value) QPHOS2 (initial value) Is zero),
QPHOS2 = QPHOS2z + ΔQP2 (6)
However, QPHOS2z: the previous value of QPHOS2,
ΔQP2: increment,
It calculates by the formula of The post-injection amount correction value QPHOS2 is a value that increases by ΔQP2 every calculation cycle.
[0061]
In step 47, a value obtained by subtracting the post injection amount correction value QPHOS2 from the post injection amount basic value QP0, that is,
QP = QP0−QPHOS2 (7)
The final post-injection amount QP is calculated by the following formula. Expression (7) is an expression for correcting the post-injection amount to be reduced.
[0062]
When the post injection amount decrease flag 2 = 1 and the main injection amount increase flag = 1 (when the engine torque is insufficient and torque fluctuation occurs and the exhaust temperature is too high), the post injection amount is reduced by the equation (7), If the main injection amount is increased according to the equation (15) described later, the filter upstream temperature T1 decreases and the engine torque increases. If the post injection amount decreases and the main injection amount continues to increase, the filter upstream temperature T1 eventually reaches the target. Fits in temperature.
[0063]
At this time, it is assumed that the angular velocity change amount Δω is also within the allowable value, and in order to finish the reduction of the post injection amount, the process proceeds from step 45 to step 48, and the post injection amount reduction flag 2 = 0 is set. The value of the correction value QPHOS2 is moved to the memory QPL2, and QPHOS2 = 0 is set in preparation for the next reproduction process. QPL2 is a decrease side correction value for the post injection amount when the filter upstream temperature T1 falls within the target temperature.
[0064]
In step 50, the post injection basic value QP0 and the memory value are used,
QP = QP0−QPL2 (8)
The final post-injection amount QP is calculated by the following formula.
[0065]
Finally, in step 51, the post injection amount reduced flag 2 = 1 is set.
(3) When the post injection amount increase flag = 1
Proceeding to step 52 in FIG. 8, it is determined whether or not the filter upstream temperature T1 is outside the target temperature. Since T1 is lower than the target temperature lower limit Tm-β when the post-injection amount increase flag 1 becomes 1 after the filter regeneration process is started, the routine proceeds to step 53, where the post-injection amount correction value (increase-side correction value) QPHOS3 ( The initial value is zero)
QPHOS3 = QPHOS3z + ΔQP3 (9)
However, QPHOS3z: the previous value of QPHOS3,
ΔQP3: increment,
It calculates by the formula of The post injection amount correction value QPHOS3 is a value that increases by ΔQP3 every calculation cycle.
[0066]
In step 54, this post injection amount correction value QPHOS3 is added to the post injection basic value QP0, that is,
QP = QP0 + QPHOS3 (10)
The final post-injection amount QP is calculated by the following formula. Expression (10) is an expression for correcting the post injection amount to be increased.
[0067]
When the post injection amount increase flag = 1 (when the engine torque is insufficient and torque fluctuation occurs and the exhaust temperature is too low), if the post injection amount is increased according to the equation (10), the filter upstream temperature T1 rises. As the engine torque increases, the upstream temperature T1 eventually falls within the target temperature as the post injection amount continues to increase.
[0068]
At this time, it is considered that the angular velocity change amount Δω is also within the allowable value, so that the post injection amount increase is terminated, the process proceeds from step 52 to step 55 and the post injection amount increase flag = 0 is set. The value QPHOS3 is transferred to the memory QPL3 and QPHOS3 = 0 is set for the next reproduction process. QPL3 is an increase correction value for the post injection amount when the filter upstream temperature T1 falls within the target temperature.
[0069]
In step 57, the post injection basic value QP0 and the memory value are used.
QP = QP0 + QPL3 (11)
The final post-injection amount QP is calculated by the following formula.
[0070]
Finally, in step 58, the post injection amount increased flag 1 = 1 is set.
[0071]
The post injection amount decrease flag 1 = 0 in step 41 in FIG. 7, the post injection amount decrease flag 2 = 0 in steps 48 and 55 in FIG. 8, and the post injection amount increase flag = 0 in FIG. .
[0072]
Steps 59 to 64 in FIG. 9 are portions for holding correction values (that is, QPL1, QPL2, QPL3) when the filter upstream temperature T1 falls within the target temperature by correction.
[0073]
In steps 59, 60, 61, the post injection amount reduced flag 1, the post injection amount reduced flag 2, and the post injection amount increased flag are viewed. When the post-injection amount reduced flag 1 = 1, the routine proceeds from step 59 to step 62, where the correction value (QPL1) when T1 falls within the target temperature is held.
QP = QP0-QPL1
The final post-injection amount QP is calculated by the following formula.
[0074]
Similarly, when the post-injection amount reduced flag 2 = 1, the process proceeds from step 59 and step 60 to step 63 to hold the correction value (QPL2) when T1 falls within the target temperature.
QP = QP0-QPL2
When the post-injection amount increased flag = 1, the process proceeds from step 59, 60, 61 to step 64 to hold the correction value (QPL3) when T1 falls within the target temperature.
QP = QP0 + QPL3
The final post-injection amount QP is calculated by the following formula.
[0075]
On the other hand, since it is not necessary to perform correction in other cases (when the angular velocity change amount Δω does not deviate from the allowable value after the start of the reproduction process), step 35 in FIG. 7 and steps 36 and 37 in FIG. 9 proceeds from step 59, 60, 61 of FIG. 9 to step 65, and the post injection basic value QP0 is used as the final post injection amount QP as it is.
[0076]
FIG. 11 is for calculating the post-injection timing ITP, and is executed every time a crank angle reference position signal (abbreviated as Ref. In the figure) is input.
[0077]
In steps 71 and 72, only when the regeneration processing flag = 1 and the post-injection region is present, the routine proceeds to step 73, where the engine speed Ne, the main injection amount basic value Qf1, and the filter upstream temperature T1 are read.
[0078]
In step 74, a post-injection timing basic value ITP0 is calculated by searching a map having the contents shown in FIG. 12 from the engine speed Ne and the main injection amount basic value Qf1. The post-injection timing basic value corresponds to the exhaust temperature that changes in accordance with the operating conditions (Ne, Qf1), and becomes a retarded side as the load becomes lower as the exhaust temperature becomes lower.
This is because the difference from the target temperature increases as the exhaust load decreases and the post-injection timing needs to be retarded accordingly. The optimum value is determined by matching.
[0079]
In step 75, the post injection timing retard flag is checked. When the post injection timing retard flag = 1, the routine proceeds to step 76, where it is determined whether or not the filter upstream temperature T1 is outside the target temperature. Since the T1 is lower than the target temperature lower limit Tm-β when the post injection timing retard flag becomes 1 after the filter regeneration process is started, the routine proceeds to step 77 and the post injection timing correction value (retard angle correction value) ITPHOS (Initial value is zero)
ITPHOS = ITPHOSz + ΔITP (12)
However, ITPHOSz: the previous value of ITPHOS,
ΔITP: increment
It calculates by the formula of The post-injection timing correction value ITPHOS is a value that increases by ΔITP every calculation cycle.
[0080]
In step 78, the post injection timing correction value ITPHOS is added to the post injection timing basic value ITP0, that is,
ITP = ITP0 + ITPHOS (13)
The final post-injection timing ITP is calculated by the following formula.
[0081]
Here, the post-injection timing basic value ITP0 is, for example, a crank angle measured from the intake bottom dead center to the advance side, and when the correction value ITPHOS is added thereto, the post-injection time moves to the retard side. That is, equation (13) is an equation for correcting the post injection timing by retarding the angle.
[0082]
When the post-injection timing retard flag = 1 (when the engine torque is excessive and torque fluctuation occurs and the exhaust gas temperature is too low), if the post-injection timing ITP is retarded, the filter upstream temperature T1 increases and the engine torque decreases. Therefore, if the delay of the post injection timing ITP is continued, the upstream temperature T1 eventually falls within the target temperature.
[0083]
At this time, it is assumed that the angular velocity change amount Δω has also become equal to or less than the allowable value α, so that the post injection timing delay is terminated, the process proceeds from step 76 to step 79 and the post injection timing delay flag = 0 is set. The value of the post injection timing correction value ITPHOS is transferred to the memory ITPL and ITPHOS = 0 is set in preparation for the next regeneration process. ITPL is a retard side correction value of the post injection timing when the filter upstream temperature T1 falls within the target temperature.
[0084]
In step 81, the post injection basic value ITP0 and the memory value are used.
ITP = ITP0 + ITPL (14)
The final post-injection timing ITP is calculated by the following formula.
[0085]
Finally, in step 82, the post injection timing retarded flag = 1 is set.
[0086]
From this post-injection timing retard flag = 0, the process proceeds from step 75 to step 83 and the post-injection timing retarded flag is viewed next time. When the post-injection timing retarded flag = 1, the routine proceeds to step 84 where the correction value (ITPL) at the time when T1 falls within the target temperature is held.
ITP = ITP0 + ITPL
The final post-injection timing ITP is calculated by the following formula.
[0087]
On the other hand, in other cases (when the angular velocity change amount Δω does not fall outside the allowable value after the start of the regeneration process), it is not necessary to perform correction. The value ITP0 is used as it is as the final post injection timing ITP.
[0088]
FIG. 13 is for calculating the main injection amount Qf, and is executed each time a crank angle reference position signal (abbreviated as Ref. In the figure) is input.
[0089]
In step 91, the engine speed Ne, the accelerator opening degree CL, and the filter upstream temperature T1 are read, and in step 92, a basic fuel injection amount Mqdrv is calculated by searching a map containing FIG. 14 from Ne and CL. In step 93, various corrections are made to the basic fuel injection amount Mqdrv based on the engine coolant temperature and the like, and the corrected value is set as a main injection amount basic value Qf1.
[0090]
In steps 94 and 95, the regeneration processing flag and the operating range are checked. Only when the regeneration processing flag = 1 and in the post-injection region, the routine proceeds to step 96 where the main injection amount increase flag is viewed. When the main injection amount increase flag = 1, the routine proceeds to step 97, where it is determined whether or not the filter upstream temperature T1 is outside the target temperature. When the main injection amount increase flag becomes 1 after the start of the filter regeneration process, the engine torque is insufficient and T1 is higher than the target temperature upper limit Tm + β, so the routine proceeds to step 98 and the main injection amount correction value (increase side correction value) is reached. ) QMHOS (initial value is zero),
QMHOS = QMHOSz + ΔQM (15)
However, QMHOSz: the previous value of QMHOS,
ΔQM: increment,
It calculates by the formula of The main injection amount correction value QMHOS is a value that increases by ΔQM every calculation cycle.
[0091]
In step 99, the main injection amount correction value QMHOS is added to the main injection amount basic value Qf1, that is,
QM1 = Qf1 + QMHOS (16)
The main injection amount QM1 is calculated by the following formula. Expression (16) is an expression for correcting the main injection amount to be increased.
[0092]
When the main injection amount increase flag = 1 (when the engine torque is insufficient and torque fluctuation occurs and the exhaust temperature is too high), if the main injection amount is increased and the post injection amount is decreased as described above, the engine torque becomes Since the exhaust temperature decreases while increasing, if the increase in the main injection amount and the decrease in the post injection amount are continued, the filter upstream temperature T1 will eventually fall within the target temperature.
[0093]
At this time, it is assumed that the angular velocity change amount Δω is also within the allowable value, so that the main injection amount increase is terminated, the process proceeds from step 97 to step 100, the main injection amount increase flag = 0, and then the main injection amount correction in step 101. The value QMHOS is moved to the memory QML, and QMHOS = 0 is set in preparation for the next reproduction process. QML is an increase correction value for the main injection amount when the filter upstream temperature T1 falls within the target temperature.
[0094]
In step 102, the main injection amount basic value Qf1 and the memory value are used.
QM1 = Qf1 + QML (17)
The main injection amount QM1 is calculated by the following formula.
[0095]
Finally, in step 103, the main injection amount increased flag = 1 is set.
[0096]
From this main injection amount increase flag = 0, next time, the process proceeds from step 96 to step 104 to see the main injection amount increase flag. When the main injection amount increased flag = 1, the routine proceeds to step 105, where the correction value (QML) when T1 falls within the target temperature is held.
QM1 = Qf1 + QML
The main injection amount QM1 is calculated by the following formula.
[0097]
On the other hand, when the regeneration process flag = 1 and the main injection amount increase flag = 0 even in the post-injection region (when the angular velocity change amount Δω does not fall outside the allowable value after the regeneration process is started). Since it is not necessary to perform correction, the routine proceeds from Steps 94, 95, 96, and 104 to Step 106. When the regeneration process flag = 0, or when the regeneration process flag = 1, it is not within the post-injection region, Step 94. 95, the routine proceeds to step 106, where the main injection amount basic value Qf1 is set as the main injection amount QM1 as it is.
[0098]
Finally, in step 107, the main injection amount QM1 calculated in this way is compared with the maximum injection amount QM1max, and when QM1 exceeds QM1max, the maximum injection amount QM1max is set as the main injection amount Qf. On the other hand, when QM1 is equal to or less than QM1max, QM1 is set as the main injection amount Qf as it is. The maximum injection amount QM1max is set according to the cylinder intake air amount Qac calculated from the air flow meter output and the engine rotational speed Ne as shown in FIG.
[0099]
Although not shown, the correction flag set flag = 0, the post injection amount decreased flag 1 = 0, the post injection amount decreased flag 2 = 0, the post injection amount increased flag = 0, The injection timing retarded flag = 0 and the main injection amount increased flag = 0. In addition, the correction amount (QPHOS1, QPHOS2, QPHOS3, ITPHOS) and the memory (QPL1, QPL2, QPL3, ITPL) are set to zero at the end timing of the reproduction process.
[0100]
Based on the post injection amount QP calculated as described above, the post injection timing ITP, the main injection amount Qf, and the main injection timing calculated by a flow (not shown), before the start of the regeneration process, the compression stroke is expanded to the expansion stroke. When the injector 8 is opened at the predetermined time and only the main injection is performed, and during the regeneration process in the post-injection region, the injector 8 is opened again and the post-injection is performed in the expansion stroke. The main injection amount basic value Qf1 is used in the flows of FIGS.
[0101]
Here, the operation of the present embodiment will be described with reference to the model diagram of FIG.
[0102]
If the post-injection region has an operating condition determined by the engine speed Ne and the fuel injection amount (main injection amount basic value). In this case, if the regeneration processing flag is 1 at the timing of t1, the regeneration is performed from the timing of t1. In addition to the main injection, post injection in the expansion stroke is executed for processing. By performing this post injection, the fuel for the post injection burns and the exhaust temperature rises. However, for convenience of explanation, it is assumed that the operating conditions are constant.
[0103]
In the figure, the main injection amount QM1 is decreased by a certain amount when post injection is applied at t1. This is because the injector 8 has the lowest injection amount due to its characteristics, and even if an injection amount less than this is commanded, the injector 8 cannot be opened, and therefore post injection cannot be performed. In order to always exceed the minimum injection amount of the injector 8, the main injection amount is decreased, and the post injection amount is increased accordingly. Further, the movement of the post injection amount is shown in an enlarged manner. Therefore, the scale of the vertical axis of the post injection amount and the scale of the main injection amount are different.
[0104]
The case of (3) above is a case where the engine torque is insufficient due to variations in the engine body and the fuel injection device, resulting in torque fluctuations and the exhaust temperature is too high. As shown in the figure, the angular velocity change amount Δω is an allowable value ( -Α) and below (see second dashed line).
On the other hand, according to the present embodiment, the main injection amount increase flag = at the timing t2 when the angular velocity change amount Δω falls below the allowable value (−α) and the filter upstream temperature T1 exceeds the target temperature upper limit Tm + β. 1 and the post-injection amount reduction flag 2 = 1. According to the instructions of these two flags, the post-injection amount QP is reduced at a constant speed by the correction value QPHOS2, and the main injection amount QM1 is at a constant speed by the correction value QMHOS. Increased.
[0105]
When the fuel correction of the main injection amount and the post injection amount is continued, the angular velocity ω of the engine output shaft is reversed from the decrease to the increase, and the filter upstream temperature T1 is also reversed from the increase to the decrease.
[0106]
If the fuel correction of the main injection amount and the post injection amount is continued until the filter upstream temperature T1 reaches the target temperature upper limit Tm + β, the angular velocity change amount Δω also falls within the allowable value (−α), so T1 becomes the target temperature upper limit. From the reached timing t3, the correction values QML and QPL2 for the main injection amount and the post injection amount at the timing t3 are maintained until the timing t4 when the regeneration process ends.
[0107]
Thus, after the regeneration process is started, the torque fluctuation Δω deviates from the permissible value (−α) and the exhaust temperature falls below the target temperature and the post-injection amount T1 is too high. As the main injection amount is increased and the post-injection is performed for regeneration, the engine torque and exhaust temperature are too high due to manufacturing variations and deterioration over time in the engine body and fuel injection device. Can occur, the exhaust temperature can be lowered to the target temperature while quickly recovering the engine torque.
[0108]
Also, if the post injection amount is reduced and the main injection amount is increased in order to reduce the exhaust temperature to the target temperature while recovering the engine torque, the exhaust temperature does not decrease sufficiently, but it is higher than the target temperature. The durability of the filter 4 deteriorates. Conversely, when the exhaust gas temperature falls too large and deviates from the target temperature, the particulates do not burn, but in this embodiment, the exhaust gas temperature falls within the target temperature. Since the post injection amount and the main injection amount are feedback-controlled, neither the durability of the filter 4 is deteriorated nor the regeneration of the filter 4 becomes insufficient.
[0109]
As described above, in the present embodiment, when the engine main body or the fuel injection device has a variation in engine torque due to manufacturing variations or deterioration with time after the start of the regeneration process by the post injection in the post injection region, the exhaust at that time is further reduced. According to the temperature, the above four cases (1) to (4) are divided into cases, and in each case, the amount and timing of the post injection are necessary so that the exhaust temperature is kept at the target temperature while eliminating the fluctuation of the engine torque. The main injection amount is also corrected (controlled) according to the conditions, so when post-injection for regeneration is performed, fluctuations in engine torque and exhaust due to manufacturing variations and deterioration over time due to engine body and fuel injection devices Even if the temperature deviates from the target temperature, it can be quickly converged to the target temperature while suppressing torque fluctuations, thereby impairing drivability. It can be carried out accurately reproduction of Rukoto without filter.
[0110]
In this case, the control target is basically only one of the fuel injection devices that perform the post injection and the main injection, and the two control parameters of the exhaust temperature and the engine torque are controlled simultaneously using only one control target. Therefore, compared with the conventional apparatus, it is possible to prevent the deterioration of fuel consumption during the filter regeneration process and to shorten the time until the exhaust temperature and the engine torque are converged to the target.
[0111]
In the embodiment, the correction value (QPHOS1, QPHOS2, ITPHOS, QPHOS3) is calculated every time the regeneration process is performed in the post-injection area. For example, in the case of (1), the regeneration process in the post-injection area is performed. Each time the engine is started, engine torque is excessively generated, torque fluctuation occurs, and the exhaust temperature is too high, and correction from there starts. In order to avoid this, learning control is introduced. For example, the value of the memory (QPL1, QPL2, ITPL, QPL3) is stored as it is after the end of the reproduction process, and the value of the memory is stored at the next reproduction process. If post-injection amount, post-injection time, and main injection amount are calculated and post-injection or main-injection is performed based on the calculated values, correction will be performed again during the next regeneration process in the post-injection region. Needless to say, it is possible to avoid a situation in which the engine torque is excessively generated, the torque fluctuates, and the exhaust gas temperature is too high.
[0112]
As a means for detecting the torque fluctuation after the start of the regeneration process, the method of calculating the angular velocity using the crank angle sensor 13 and estimating it from the amount of change is common as described above. It is also possible to estimate from the amount of change in the throttle opening detected by the sensor.
[0113]
In the embodiment, in the case of (3) above (when the engine torque is insufficient and torque fluctuation occurs and the exhaust temperature is too high), the main injection amount is increased and the post injection amount is decreased. As shown in FIG. 17, the post injection timing may be advanced from the broken line to the solid line (second embodiment). Further, both means for increasing the main injection amount and decreasing the post injection amount and means for advancing the post injection timing may be used in combination.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.
FIG. 2 is an operation region diagram for performing regeneration processing.
FIG. 3 is a PV diagram showing the difference between the case with and without post injection.
FIG. 4 is a flowchart for explaining setting of a correction flag.
FIG. 5 is a flowchart for explaining setting of a correction flag.
FIG. 6 is an injection waveform diagram for explaining correction contents.
FIG. 7 is a flowchart for explaining calculation of a post injection amount.
FIG. 8 is a flowchart for explaining calculation of a post injection amount.
FIG. 9 is a flowchart for explaining calculation of a post injection amount.
FIG. 10 is a characteristic diagram of a post injection basic value.
FIG. 11 is a flowchart for explaining calculation of a post injection timing.
FIG. 12 is a characteristic diagram of a post injection timing basic value.
FIG. 13 is a flowchart for explaining calculation of a main injection amount.
FIG. 14 is a characteristic diagram of a basic fuel injection amount.
FIG. 15 is a characteristic diagram of a maximum injection amount.
FIG. 16 is a waveform diagram for explaining the operation when torque is insufficient, torque fluctuation occurs, and the exhaust temperature is too high.
FIG. 17 is an injection waveform diagram for explaining correction contents of the second embodiment.
[Explanation of symbols]
1 engine
2 Intake passage
3 Exhaust passage
4 filters
8 Injector
11 Controller
12 Differential pressure sensor
13 Crank angle sensor

Claims (19)

In an exhaust emission control device for an engine having a filter for collecting particulates in an exhaust passage,
Post injection amount / time setting means for setting the basic value of post injection amount or the basic value of post injection time according to the engine speed and load,
When the filter regeneration time comes, regeneration processing means for increasing the exhaust gas temperature by post injection using the post injection basic value or the post injection timing basic value and performing filter regeneration processing;
Torque fluctuation determination means for determining whether there is a fluctuation in engine torque during the regeneration process of the filter;
A determination means for determining whether or not the exhaust gas temperature further deviates from the target temperature when the engine torque varies from the determination result;
From this determination result, the engine output shaft angular velocity change amount is larger than the allowable value and the exhaust temperature is higher than the target temperature, and the engine output shaft angular velocity change amount is less than the allowable value and the exhaust temperature is but only the post injection amount basic value as at the same time the exhaust gas temperature while suppressing the fluctuation of the engine torque in the case lower deviates from the target temperature falls to the target temperature, also the amount of change in angular velocity of the engine output shaft from the determination result Post-injection correction means for correcting only the basic value of the post-injection timing so that the exhaust temperature falls within the target temperature while suppressing fluctuations in the engine torque when the allowable value is large and the exhaust temperature is low and deviating from the target temperature. When,
An exhaust gas purification apparatus comprising: a fuel supply device that performs post injection corrected by the post injection correction means.   The exhaust gas purification apparatus according to claim 1, wherein the fluctuation of the engine torque is when the change amount of the angular velocity of the engine output shaft deviates from an allowable value.   3. The post-injection amount basic value is corrected to a reduction side when the amount of change in the angular velocity of the engine output shaft is large outside the allowable value and the exhaust temperature is high outside the target temperature. Exhaust purification equipment.   The post-injection timing basic value is corrected to the retard side when the change amount of the angular velocity of the engine output shaft is large outside the allowable value and the exhaust temperature is low outside the target temperature. The exhaust emission control device described.   Means for setting a main injection amount basic value according to the engine speed and load, and when the amount of change in the angular speed of the engine output shaft falls below an allowable value and the exhaust temperature is higher than the target temperature, The exhaust emission control device according to claim 2, wherein the post injection basic value is corrected to the decreasing side and the main injection basic value is corrected to the increasing side.   The post-injection amount basic value is corrected to the increase side when the change amount of the angular velocity of the engine output shaft falls below the allowable value and the exhaust temperature is low outside the target temperature. Exhaust purification equipment.   The exhaust emission control device according to claim 3, wherein the post-injection amount basic value is continuously corrected to the decreasing side until the exhaust temperature falls within the target temperature.   The exhaust emission control device according to claim 4, wherein the post-injection timing basic value is continuously corrected to the retard side until the exhaust temperature falls within the target temperature.   The exhaust emission control device according to claim 5, wherein the post-injection amount basic value is continuously corrected to the decreasing side until the exhaust temperature falls within the target temperature.   The exhaust emission control device according to claim 6, wherein the post-injection amount basic value is continuously corrected to the increase side until the exhaust temperature falls within the target temperature. In an exhaust emission control device for an engine having a filter for collecting particulates in an exhaust passage,
Post injection amount / time setting means for setting the basic value of post injection amount or the basic value of post injection time according to the engine speed and load,
When the filter regeneration time comes, regeneration processing means for increasing the exhaust gas temperature by post injection using the post injection basic value or the post injection timing basic value and performing filter regeneration processing;
Torque fluctuation determination means for determining whether there is a fluctuation in engine torque during the regeneration process of the filter;
A determination means for determining whether or not the exhaust gas temperature further deviates from the target temperature when the engine torque varies from the determination result;
From this determination result, the engine output shaft angular velocity change amount is larger than the allowable value and the exhaust temperature is higher than the target temperature, and the engine output shaft angular velocity change amount is less than the allowable value and the exhaust temperature is but only the post injection amount basic value as at the same time the exhaust gas temperature while suppressing the fluctuation of the engine torque in the case lower deviates from the target temperature falls to the target temperature, also the amount of change in angular velocity of the engine output shaft from the determination result When the exhaust temperature is too large outside the allowable value and the exhaust temperature is too low from the target temperature, only the post-injection timing basic value is corrected so that the exhaust temperature falls within the target temperature while suppressing fluctuations in engine torque. Suppresses fluctuations in engine torque when the engine output shaft angular velocity change is less than the allowable value and the exhaust temperature is higher than the target temperature. And post-main injection correction means simultaneously exhaust temperature corrects the post injection amount basic value and the main injection to fit the target temperature while,
An exhaust emission control device comprising: a post-injection corrected by the post-main injection correction means; and a fuel supply device that performs main injection.   The exhaust gas purification apparatus according to claim 11, wherein the torque fluctuation is a case where an amount of change in angular velocity of the engine output shaft deviates from an allowable value.   A means for setting the main injection amount basic value according to the engine speed and load is provided.When the change in the angular speed of the engine output shaft falls below the allowable value and the exhaust temperature is high outside the target temperature, the post 12. The exhaust emission control device according to claim 11, wherein the injection amount basic value is corrected to the decrease side and the main injection amount basic value is corrected to the increase side.   The exhaust emission control device according to claim 13, wherein the post-injection amount basic value is continuously corrected to the decreasing side and the main injection amount basic value is continuously corrected to the increasing side until the exhaust temperature falls within the target temperature.   The correction value to the reduction side when the exhaust temperature falls within the target temperature is stored, and the stored correction value to the reduction side is used for the calculation of the post injection amount at the next regeneration processing. 8. An exhaust emission control device according to 7.   The correction value to the increase side when the exhaust temperature falls within the target temperature is stored, and the stored correction value to the increase side is used for the calculation of the post injection amount at the next regeneration processing. The exhaust emission control device according to 10.   The correction value to the retard side when the exhaust temperature falls within the target temperature is stored, and the stored correction value to the retard side is used for the calculation of the post injection timing at the next regeneration processing. The exhaust emission control device according to claim 8.   The correction value to the advance side when the exhaust temperature falls within the target temperature is stored, and the stored correction value to the advance side is used for the calculation of the post injection timing at the next regeneration processing. The exhaust emission control device according to claim 9.   Stores the correction value to the decrease side with respect to the post injection basic value when the exhaust temperature falls within the target temperature, and the correction value to the increase side with respect to the main injection amount basic value, and each stored correction value is reproduced next time. The exhaust emission control device according to claim 14, wherein the exhaust purification device is used for calculating a post injection amount and a main injection amount during processing.

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