JP2004346755A - Control device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent overheating of an engine, in which first after-injection and second after-injection are performed after main injection is performed around an top dead center in a compression stroke so as to regenerate a particulate filter 17. <P>SOLUTION: An oxidation catalyst 16 and a filter 17 are disposed to an exhaust passage 3 of the engine 1. The oxidation catalyst 16 is heated by increasing an exhaust gas temperature in the first after-injection, and then unburnt fuel is supplied to the oxidation catalyst 16 by the second after-injection to increase a temperature of the filter 17 by its oxidization combustion and thereby to burn particulates trapped in the filter 17. When an engine water temperature is increased to a first predetermined value or higher, the first after-injection is suppressed, and when the engine water temperature is decreased to a second predetermined value or lower, the suppression of the first after-injection is released. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for an engine having a particulate filter in an exhaust passage.
[0002]
[Prior art]
The particulate filter needs to be regenerated by burning and removing the collected particulates when the collected amount of the particulates (exhaust particulates) becomes equal to or more than a predetermined amount. Regarding the regeneration of the filter, an oxidation catalyst is disposed in an exhaust passage upstream of the filter, and by supplying unburned fuel to the oxidation catalyst to perform oxidative combustion, the temperature of exhaust gas flowing into the filter is increased. It is known to burn particulates of a filter (see Patent Document 1).
[0003]
In Patent Document 1, the temperature of exhaust gas flowing into the oxidation catalyst is detected, and when the temperature of the exhaust gas is equal to or higher than a predetermined value, the main injection of fuel into the in-cylinder combustion chamber near the top dead center of the compression stroke is performed. Thereafter, by performing post-injection of injecting fuel into the in-cylinder combustion chamber immediately before closing of the exhaust valve, unburned fuel is supplied to the oxidation catalyst. That is, it is determined whether or not the oxidation catalyst is in an active state based on the temperature of the exhaust gas flowing into the oxidation catalyst. When the temperature of the exhaust gas is low, post-injection for filter regeneration is not performed. .
[0004]
[Patent Document 1]
JP-A-8-42326
[Problems to be solved by the invention]
By the way, even when the temperature of the oxidation catalyst is low, if the post-injection is performed at a relatively early stage of the expansion stroke after the main injection, the injected fuel burns in the cylinder and the exhaust gas temperature rises. The regeneration of the filter can be promoted by promoting the activity of the catalyst. Further, it is possible to prevent the temperature of the oxidation catalyst from being lowered by the post-injection at the early stage of the expansion stroke. it can.
[0006]
However, if the post-injection is executed early in the expansion stroke, the engine is heated excessively by the combustion of the post-injected fuel in the cylinder. There is a risk of overheating. Of course, if the cooling performance is enhanced by increasing the size of the cooling fan of the engine, such a problem is eliminated. However, increasing the cooling performance increases the cost and the size of the cooling device, which is not a good idea.
[0007]
That is, an object of the present invention is to prevent engine overheating when performing post-injection early in the expansion stroke for regeneration of the filter.
[0008]
Another object of the present invention is to efficiently regenerate the filter while avoiding overheating of the engine.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention suppresses post-injection early in the expansion stroke when the engine water temperature tends to increase even during filter regeneration.
[0010]
That is, the invention according to claim 1 includes a particulate filter provided in an exhaust passage of an engine;
Collection amount detection means for detecting the amount of particulate collected by the filter,
An oxidation catalyst provided in the exhaust passage upstream of the filter,
When the trapping amount detected by the trapping amount detecting means is equal to or greater than a predetermined value, in the expansion stroke after the main injection, in which fuel is injected into the in-cylinder combustion chamber of the engine near the top dead center of the compression stroke. A first post-injection for injecting fuel into the in-cylinder combustion chamber so that the temperature of exhaust gas flowing into the oxidation catalyst increases, and a method for supplying unburned fuel to the oxidation catalyst after the first post-injection. And a second post-injection for injecting fuel into the in-cylinder combustion chamber, whereby the particulate matter collected by the filter is burned to regenerate the filter, thereby regenerating the filter. Detecting means for detecting a parameter value related to an engine water temperature (cooling water temperature) of the engine,
The regeneration means determines that the engine coolant temperature has become equal to or higher than a first predetermined value based on the parameter value during regeneration of the filter by the first post-injection and the second post-injection. Is suppressed.
[0011]
Therefore, when the trapping amount of the particulate filter becomes equal to or more than the predetermined value, the temperature of the exhaust gas flowing into the oxidation catalyst is increased by performing the first post-injection, and the activity of the oxidation catalyst is promoted, or The oxidation catalyst is maintained in a highly active state, and the unburned fuel supplied by the second post-injection can be efficiently oxidized and burned. Due to the oxidative combustion of the unburned fuel, the temperature of the exhaust gas flowing into the filter increases, and the particulates collected by the filter are efficiently burned and removed.
[0012]
Thus, the execution of the first post-injection causes the engine water temperature to rise. When the engine water temperature becomes equal to or higher than the first predetermined value, the first post-injection is suppressed (not only the stop of the first post-injection but also the stoppage). Since the first post-injection amount is reduced, the engine water temperature is prevented from excessively rising due to a high outside air temperature or the like, and engine overheating is avoided.
[0013]
The second post-injection may be executed in an expansion stroke after the first post-injection or in a subsequent exhaust stroke. The suppression of the first post-injection may be to reduce the injection amount thereafter or to stop the post-injection. The means for detecting the parameter value related to the engine water temperature is not limited to the temperature sensor for detecting the engine water temperature, but may be any means as long as it can determine the level of the engine water temperature.
[0014]
According to a second aspect of the present invention, in the engine control device according to the first aspect,
When the regeneration means determines that the engine water temperature has become equal to or lower than a second predetermined value lower than the first predetermined value based on the parameter value after the suppression of the first post-injection, the suppression is released. It is characterized by.
[0015]
Therefore, it is advantageous in regenerating the filter without causing overheating of the engine while avoiding hunting in which the execution and stop of the first post-injection is frequently repeated.
[0016]
According to a third aspect of the present invention, in the engine control device according to the second aspect,
Means for detecting a parameter value related to the outside air temperature;
And a threshold value correcting unit that decreases the first predetermined value and the second predetermined value as the outside air temperature increases based on a parameter value related to the outside air temperature.
[0017]
That is, as the outside air temperature increases, the engine water temperature rises due to the first post-injection, and overheating is more likely to occur. Therefore, in the present invention, the first predetermined value is reduced as the outside air temperature increases, and the first post-injection is suppressed early when the engine water temperature starts to rise, so that the overheating can be reliably prevented. It was done. The hunting is avoided by changing the second predetermined value in conjunction with the first predetermined value.
[0018]
The means for detecting the parameter value related to the outside air temperature is not limited to the temperature sensor for detecting the outside air temperature, but may be a temperature sensor for detecting the intake air temperature of the engine. For example, the level of the outside air temperature can be determined based on the changing speed of the parameter value related to the engine water temperature when the first post-injection is executed. That is, the engine water temperature (water temperature determined based on the engine water temperature related parameter value) increases with the execution of the first post-injection, but the third predetermined value is lower than the second predetermined value. May be measured from when the second predetermined value is reached, and the shorter the time is, the higher the outside air temperature is. The first predetermined value and the second predetermined value may be decreased.
[0019]
According to a fourth aspect of the present invention, in the engine control device according to the second or third aspect,
The regeneration means determines that the engine water temperature has become equal to or higher than a first predetermined value based on the parameter value during regeneration of the filter by the first post-injection and the second post-injection. And suppressing the second injection when the engine coolant temperature is determined to be equal to or lower than a predetermined intermediate value between the first predetermined value and the second predetermined value. And
[0020]
That is, since the second post-injection supplies unburned fuel to the oxidation catalyst, the effect on the engine water temperature is not significant, but when the first post-injection is suppressed, the temperature of the oxidation catalyst decreases and the activity decreases. As the unburned fuel due to the second post-injection may not be effectively used for the regeneration of the filter, when it is determined that the engine water temperature has become equal to or higher than the first predetermined value, the fuel injection is performed together with the first post-injection. Two injections are also suppressed.
[0021]
On the other hand, when the engine water temperature becomes equal to or lower than the intermediate predetermined value between the first predetermined value and the second predetermined value, after a while, the engine water temperature drops to the second predetermined value or lower and the suppression of the first post-injection is released. Is done. Therefore, the suppression of the second post-injection is canceled in advance, and the unburned fuel is supplied to the oxidation catalyst to perform oxidative combustion, thereby preventing the oxidation catalyst temperature and the filter temperature from excessively lowering. When the suppression of the first post-injection is released and the temperature of the oxidation catalyst rises, full-scale regeneration of the filter can be promptly restarted.
[0022]
According to a fifth aspect of the present invention, in the engine control device according to the first aspect,
The regeneration means determines that the engine coolant temperature has become equal to or higher than a first predetermined value based on the parameter value during regeneration of the filter by the first post-injection and the second post-injection. Only the second post-injection is continued.
[0023]
That is, since the second post-injection supplies unburned fuel to the oxidation catalyst and has almost no effect on the engine water temperature, the present invention suppresses the first post-injection (in addition to stopping the first post-injection, , Including the first post-injection amount), the second post-injection is continued. Then, by continuing the second post-injection, when the suppression of the first post-injection is released and the temperature of the oxidation catalyst rises, full-scale regeneration of the filter by oxidizing combustion of the unburned fuel is performed. It is intended to be able to resume promptly.
[0024]
【The invention's effect】
As described above, according to the first aspect of the present invention, there is provided detecting means for detecting a parameter value related to the engine water temperature, and the parameter value is set during the regeneration of the particulate filter by the first post-injection and the second post-injection. The first post-injection is suppressed when it is determined that the engine water temperature has become equal to or higher than a first predetermined value based on the value of the engine. Overheating can be prevented.
[0025]
According to the second aspect of the present invention, in the first aspect, when it is determined that the engine coolant temperature has become equal to or less than a second predetermined value lower than the first predetermined value after the suppression of the first post-injection. Since the suppression is released, it is advantageous in regenerating the filter without causing overheating of the engine while avoiding hunting in which the execution and stop of the first post-injection is frequently repeated.
[0026]
According to the third aspect of the present invention, when the engine water temperature starts to increase, the second aspect includes the threshold value correcting means for decreasing the first predetermined value and the second predetermined value as the outside air temperature increases. As a result, the first post-injection can be suppressed as early as possible to reliably prevent the overheating, and the hunting can be avoided.
[0027]
According to the fourth aspect of the present invention, in the second or third aspect, when it is determined that the engine coolant temperature has become equal to or higher than the first predetermined value during the filter regeneration by the first post-injection and the second post-injection. The second post-injection is suppressed together with the first post-injection, and when it is determined that the engine coolant temperature is equal to or lower than a predetermined intermediate value between the first predetermined value and the second predetermined value, the suppression of the second post-injection is performed. When the suppression of the first post-injection is released while preventing the fuel consumption rate from deteriorating due to useless second post-injection, full-scale combustion by oxidizing combustion of the unburned fuel is performed. Regeneration of the filter can be quickly resumed.
[0028]
According to the invention according to claim 5, in claim 1, the engine water temperature exceeds a first predetermined value based on the parameter value during regeneration of the filter by the first post-injection and the second post-injection. When the determination is made, the first post-injection is suppressed and the second post-injection is continued. When the suppression of the first post-injection is released and the activity of the oxidation catalyst becomes high, the unburned fuel It is possible to quickly restart full-scale regeneration of the filter by oxidative combustion of the filter.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0030]
In the engine control device shown in FIG. 1, 1 is a multi-cylinder diesel engine (only one cylinder is shown in FIG. 1), 2 is an intake passage, and 3 is an exhaust passage. A deep-dish combustion chamber 5 is formed on the top surface of the piston 4 of the engine 1. A fuel injection valve 7 is provided in the cylinder head of the engine 1 so as to be able to directly inject and supply fuel to the in-cylinder combustion chamber 5 near the top dead center of the compression stroke. Glow plug 8 is provided for warming.
[0031]
In the intake passage 2, in order from the upstream side to the downstream side, an air cleaner 9, an air flow sensor 10, a blower 11 a of a turbocharger 11, an intercooler 12, an intake throttle valve 13, and parameter values related to outside air temperature An intake air temperature sensor 14 and an intake air pressure sensor 15 are provided as means for detecting the pressure. In the exhaust passage 3, a turbine 11b of the turbocharger 11, an oxidation catalyst 16, and a particulate filter 17 are arranged in this order from the upstream side to the downstream side.
[0032]
Exhaust pressure sensors 18 and 19 are disposed upstream and downstream of the particulate filter 17. The two exhaust pressure sensors 18 and 19 constitute a particulate trapping amount detecting means. That is, the amount of the particulates collected by the particulate filter 17 is detected based on the differential pressure between the exhaust pressures detected by the two sensors 18 and 19. Can be determined to be large.
[0033]
Further, a portion of the exhaust passage 3 upstream of the turbine 11b and a portion of the intake passage 2 downstream of the intake pressure sensor 15 form an exhaust gas recirculation passage for returning part of exhaust gas to the intake system. 21. Hereinafter, the exhaust gas recirculation is referred to as EGR. A negative pressure actuator type EGR valve 22 and a cooler 23 for cooling exhaust gas with engine cooling water are provided in the EGR passage 21.
[0034]
Fuel is supplied to the fuel injection valve 7 from a fuel injection pump (not shown) through a fuel supply pipe 25 via a common rail (not shown) as pressure accumulating means, and is returned to a fuel tank (not shown) by a fuel return pipe 24. It is. 26 is a water temperature sensor for detecting the engine water temperature, 27 is a crank angle sensor for detecting the engine speed, 28 is a first exhaust gas temperature sensor for detecting the temperature of exhaust gas flowing into the oxidation catalyst 16, and 29 is a particulate filter 17. A second exhaust gas temperature sensor 30 for detecting the temperature of the inflowing exhaust gas, and a third exhaust gas temperature sensor 30 for detecting the temperature of the exhaust gas flowing out of the particulate filter 17.
[0035]
The fuel injection valve 7, the glow plug 8, the turbocharger 11, and the EGR valve 22 are controlled by an ECU (engine control unit) 35 using a microcomputer shown in FIG. .
[0036]
The fuel injection control using the fuel injection valve 7 by the ECU 35 includes a main injection control for injecting fuel near a top dead center in a compression stroke for generating an engine output, and a post-injection control for regeneration of the particulate filter 17. There is.
[0037]
The main injection control is basically performed based on the engine speed and the engine load, and is further corrected based on the engine water temperature, the intake air temperature, and the like. As for the engine load, a detection signal is given to the ECU 35 from the accelerator opening sensor 32 which detects the accelerator opening (the amount of depression of the accelerator pedal).
[0038]
The post-injection control, that is, the filter regeneration control, is based on the intake temperature sensor 14, the exhaust pressure sensors 18, 19, the water temperature sensor 26, the crank angle sensor 27, the exhaust gas temperature sensors 28 to 29, the accelerator opening sensor 32, and the like. Done. For this filter regeneration control, the ECU 35 is provided with a regeneration means 36 and a threshold value correction means 37.
[0039]
(Filter regeneration control)
Hereinafter, the regeneration control of the filter 17 will be specifically described.
[0040]
The regenerating means 36 operates the fuel injection valve 7 when the amount of trapped particulates of the filter 17 becomes a predetermined value or more to inject fuel so that the temperature of exhaust gas flowing into the oxidation catalyst 16 increases. A first post-injection is performed, and a second post-injection for injecting fuel such that unburned fuel is supplied to the oxidation catalyst 16 is executed.
[0041]
Further, when it is determined that the engine water temperature has become equal to or higher than the first predetermined value during the regeneration of the filter 17, the regenerating means 36 suppresses the first post-injection and the second post-injection, and sets the engine water temperature to the first predetermined value. When it is determined that the value becomes equal to or less than the second predetermined value smaller than the value, the suppression of the first post-injection is released, and the suppression of the second post-injection is performed when the engine coolant temperature is intermediate between the first predetermined value and the second predetermined value. Is released when it is determined that it is equal to or less than the fourth predetermined value.
[0042]
Further, the threshold value correcting means 37 is configured to decrease the first predetermined value and the second predetermined value as the outside air temperature detected by the intake air temperature sensor 14 increases. That is, as shown in FIG. 3, when the outside air temperature is 0 ° C. or lower, the first predetermined value and the second predetermined value are set to substantially constant high temperatures, but the outside air temperature rises beyond 0 ° C. As it goes, the first predetermined value and the second predetermined value gradually decrease. However, the temperature difference between the first predetermined value and the second predetermined value is set to be substantially constant regardless of the level of the outside air temperature.
[0043]
FIG. 4 shows a flow of the filter regeneration control. In step S1 after the start, the differential pressure ΔP is obtained based on the pressures detected by the exhaust pressure sensors 18 and 19 before and after the particulate filter 17, and in step S2, the particulate collection amount M is calculated based on the differential pressure ΔP. I do. In step S3, the engine coolant temperature TW detected by the coolant temperature sensor 26 is read.
[0044]
In the following step S4, it is determined whether or not the particulate collection amount M is equal to or more than a predetermined value α (for example, 10 g per 1 L of the filter). When the trapping amount M is not equal to or more than the predetermined value α, the process returns. When the trapping amount M is equal to or larger than the predetermined value α, the process proceeds to step S5, and the first post-injection A and the second post-injection B are executed. However, the process proceeds to step S5 on condition that the temperature of the exhaust gas flowing into the oxidation catalyst 16 based on the output of the exhaust gas temperature sensor 28 is equal to or higher than a predetermined value (the temperature at which the oxidation catalyst 16 exhibits a predetermined activity).
[0045]
The injection amount and the injection timing of the first post-injection A and the second post-injection B are set with reference to a map based on the engine operating state. FIG. 5 shows an example of the first post injection amount map, and FIG. 6 shows an example of the second injection amount map. The numerical values assigned to the respective regions in FIGS. 5 and 6 indicate the fuel injection amount per one stroke (one expansion stroke) of one cylinder. In these maps, basically, the post-injection amount is set to increase as the engine load decreases and as the engine speed decreases. This is because the lower the engine load and the lower the engine speed, the lower the exhaust gas temperature due to the main injection and the smaller the exhaust gas amount. However, the second post-injection amount is generally smaller than the first post-injection amount.
[0046]
FIG. 7 shows an example of the first post injection timing map, and FIG. 8 shows an example of the second injection timing map. 7 and 8 represent the crank angle of ATDC (after the top dead center of the compression stroke). Regarding the first post-injection timing, in order to increase the exhaust gas temperature while avoiding the influence on the engine output (torque shock), in the range of ATDC 20 to 35 ° CA (crank angle), as the engine load increases and the engine speed increases. The higher the number, the slower it is set. On the other hand, with respect to the second post-injection timing, the post-injection fuel is slightly thermally decomposed and discharged so as to be easily burned by the oxidation catalyst. It is set so that the higher the number of rotations, the lower the speed.
[0047]
By the execution of the first post-injection A, the temperature of the exhaust gas of the engine 1 rises, and accordingly, the temperature of the oxidation catalyst 16 rises to show high activity. Therefore, the unburned fuel supplied to the oxidation catalyst 16 by the second post-injection B efficiently oxidizes and combusts, the temperature of the exhaust gas flowing into the filter 17 increases, and the particulates ignite and combust, thereby regenerating the filter 17. Goes on.
[0048]
In step S6 following the execution step S5 of the post injections A and B, it is determined whether or not the engine coolant temperature TW detected by the coolant temperature sensor 26 is equal to or higher than a first predetermined value. When the engine coolant temperature TW is not equal to or higher than the first predetermined value, the process proceeds to step S7, in which the particulate collection amount M is equal to or lower than a predetermined value β (for example, 1 g per 1 L of the filter), that is, the regeneration of the filter 17 is completed. It is determined whether or not it has been performed. When the regeneration of the filter 17 has been completed, the process proceeds to step S8 to stop the post-injection A and B, and returns. If the regeneration of the filter 17 has not been completed, the flow returns to step S5 to continue the regeneration of the filter 17 by the post injections A and B.
[0049]
On the other hand, when it is determined in step S6 that the engine water temperature is equal to or higher than the first predetermined value, the process proceeds to step S9, in which the first post-injection A and the second post-injection B are suppressed. That is, the post injections A and B are stopped (the post injection amount may be reduced). As a result, as shown in FIG. 9, the engine water temperature, which has risen with the execution of the first post-injection A, falls before entering the overheat zone.
[0050]
In the following step S10, it is determined whether or not the engine water temperature has dropped below a fourth predetermined value. When the engine coolant temperature becomes equal to or lower than the fourth predetermined value, the process proceeds to step S11 to release the suppression of the second post-injection B (restart the second post-injection B). As a result, the unburned fuel is supplied to the oxidation catalyst 16, and the heat of the oxidation combustion prevents the temperatures of the oxidation catalyst 16 and the filter 17 from being excessively reduced, or the temperatures of the oxidation catalyst 16 and the filter 17 can be increased.
[0051]
In the following step S12, it is determined whether or not the engine coolant temperature TW has dropped below a second predetermined value. When the engine coolant temperature TW has dropped below the second predetermined value, the routine proceeds to step S13, where the suppression of the first post-injection A is released (the first post-injection A is restarted), and the routine proceeds to step S7. In this case, as described above, the second post-injection B is restarted in advance and the temperature of the oxidation catalyst 16 and the filter 17 are prevented from lowering. Therefore, the temperature of the oxidation catalyst 16 is increased by restarting the first post-injection A. At this time, efficient oxidative combustion of the unburned fuel starts burning quickly, and the regeneration efficiency of the filter 17 increases.
[0052]
Further, the first predetermined value and the second predetermined value gradually decrease due to the correction by the threshold value correcting means 37 when the outside air temperature exceeds 0 ° C. Therefore, when the outside air temperature is high, the When the water temperature starts to increase, the first post-injection is suppressed early, and the first post-injection A prevents the engine water temperature from excessively increasing and causing overheating. Further, in response to a change in the outside air temperature, the second predetermined value also changes while maintaining a substantially constant temperature difference in conjunction with the first predetermined value. Can be avoided.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of an engine control device according to an embodiment of the present invention.
FIG. 2 is a block diagram relating to filter regeneration control of the control device.
FIG. 3 is a graph showing a relationship between first and second predetermined values of the regeneration control and an outside air temperature.
FIG. 4 is a flowchart of the reproduction control.
FIG. 5 is a control map of a first post-injection amount in the regeneration control.
FIG. 6 is a control map of a second post-injection amount in the regeneration control.
FIG. 7 is a control map of a first post-injection timing in the regeneration control.
FIG. 8 is a control map of a second post-injection timing in the regeneration control.
FIG. 9 is a graph showing the change over time of the engine water temperature in the regeneration control.
[Explanation of symbols]
Reference Signs List 1 engine 2 intake passage 3 exhaust passage 5 in-cylinder combustion chamber 7 fuel injection valve 14 intake temperature sensor 16 oxidation catalyst 17 particulate filters 18, 19 exhaust pressure sensor 26 water temperature sensor 35 ECU
36 reproducing means 37 threshold value correcting means

Claims (5)

A particulate filter provided in an exhaust passage of the engine,
Collection amount detection means for detecting the amount of particulate collected by the filter,
An oxidation catalyst provided in the exhaust passage upstream of the filter,
When the trapping amount detected by the trapping amount detecting means is equal to or greater than a predetermined value, in the expansion stroke after the main injection, in which fuel is injected into the in-cylinder combustion chamber of the engine near the top dead center of the compression stroke. A first post-injection for injecting fuel into the in-cylinder combustion chamber so that the temperature of exhaust gas flowing into the oxidation catalyst increases, and a method for supplying unburned fuel to the oxidation catalyst after the first post-injection. And a second post-injection for injecting fuel into the in-cylinder combustion chamber, whereby the particulate matter collected by the filter is burned to regenerate the filter, thereby regenerating the filter. And detecting means for detecting a parameter value related to the engine water temperature of the engine,
The regeneration means determines that the engine coolant temperature has become equal to or higher than a first predetermined value based on the parameter value during regeneration of the filter by the first post-injection and the second post-injection. A control device for an engine, characterized in that the control is performed. In claim 1,
When the regeneration means determines that the engine water temperature has become equal to or lower than a second predetermined value lower than the first predetermined value based on the parameter value after the suppression of the first post-injection, the suppression is released. An engine control device characterized by the above-mentioned. In claim 2,
Means for detecting a parameter value related to the outside air temperature;
An engine control device comprising: a threshold value correction unit that decreases the first predetermined value and the second predetermined value as the outside air temperature increases based on a parameter value related to the outside air temperature. In claim 2 or claim 3,
The regeneration means determines that the engine water temperature has become equal to or higher than a first predetermined value based on the parameter value during regeneration of the filter by the first post-injection and the second post-injection. And suppressing the second injection when the engine coolant temperature is determined to be equal to or lower than a predetermined intermediate value between the first predetermined value and the second predetermined value. Engine control device. In claim 1,
The regeneration unit is configured to determine whether the engine coolant temperature has become equal to or higher than a first predetermined value based on the parameter value during regeneration of the filter by the first post-injection and the second post-injection. An engine control unit that suppresses only injection and continues the second post-injection.

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