JP2006316742A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine capable of preventing torque fluctuation and deterioration of exhaust gas characteristics immediately after completion of unburned fuel supply and of securing stable EGR operation. <P>SOLUTION: This control device for the internal combustion engine is provided with an EGR passage 14a connected between an exhaust system 5 and an intake system 4 of the internal combustion engine and recirculating part of exhaust gas from the exhaust system 5 to the intake system 4 as EGR gas; an EGR means (EGR control valve 14b) recirculating EGR gas via the EGR passage 14a; an exhaust emission control device 20 provided in the downstream side from the EGR passage 14a of the exhaust system 5; an unburned fuel supply means 6 supplying unburned fuel to exhaust gas to regenerate the exhaust emission control device 20; and an EGR prohibiting means (ECU 2) prohibiting execution of EGR by the EGR means 14b until predetermined time TMREF passes after completion of unburned fuel supply by an unburned fuel supply means 6 (injector 6). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine that supplies unburned fuel to regenerate an exhaust gas purification device and has an EGR device.

  As a conventional control device for this type of internal combustion engine, for example, one disclosed in Patent Document 1 is known. The control device includes an EGR passage connected between the intake system and the exhaust system, and an EGR valve provided in the EGR passage, according to the operating state of the internal combustion engine (hereinafter referred to as “engine”). By controlling the opening degree of the EGR valve, an EGR operation for recirculating a part of the exhaust gas from the exhaust system to the intake system is executed.

  Further, a NOx occlusion reduction catalyst is provided downstream of the EGR passage of the exhaust system, and when the internal combustion engine is operated at an air / fuel ratio leaner than the stoichiometric air / fuel ratio, NOx in the exhaust gas is occluded by NOx. Occlusion in the reduction catalyst suppresses NOx emission into the atmosphere. Further, when the amount of stored NOx becomes larger than a predetermined value, unburned fuel is included in the exhaust gas by post-injecting the fuel into the cylinder in the expansion stroke or the exhaust stroke, whereby NOx is converted into NOx. The NOx storage reduction catalyst is regenerated by releasing and reducing from the storage reduction catalyst.

  Further, during the post-injection as described above, the EGR valve is fully closed in order to prevent recirculation of exhaust gas containing unburned fuel to the intake system and the resulting rich air-fuel ratio of the air-fuel mixture. Be controlled.

  Further, as a conventional exhaust gas purifying apparatus, one that purifies exhaust gas by collecting particulates in the exhaust gas with a filter is known, and is disclosed in Patent Document 2, for example. In this exhaust gas purifying apparatus, in order to avoid a decrease in engine output and a deterioration in fuel consumption due to an increase in exhaust pressure when the amount of particulate (hereinafter referred to as “PM”) accumulation on the filter increases, the following is performed. Play the filter.

  That is, the amount of PM deposited on the filter is estimated, and the filter is regenerated when the estimated amount of PM deposited is greater than a predetermined threshold. Specifically, in addition to the fuel required for engine combustion, unburned fuel is included in the exhaust gas by post injection that injects fuel into the combustion chamber during the exhaust stroke, and this unburned fuel is filtered from the filter in the exhaust pipe. Also, the PM is accumulated on the filter by burning it upstream and forcibly raising the exhaust gas temperature to regenerate the filter.

  In the control device of Patent Document 1 described above, immediately after the post-injection for regeneration of the NOx storage reduction catalyst is completed, exhaust gas containing unburned fuel is still upstream of the exhaust system NOx storage reduction catalyst. It remains. Therefore, when the execution of the EGR operation is started with the end of the post injection, the unburned fuel existing on the upstream side of the NOx storage reduction catalyst is returned to the intake system together with the EGR gas, and is sucked into the combustion chamber. For this reason, the air-fuel ratio of the air-fuel mixture in the cylinder becomes rich with respect to the unburned fuel, and as a result, torque fluctuations may occur and exhaust gas characteristics may deteriorate.

  Further, the unburned fuel that recirculates together with the EGR gas adheres to the EGR passage, so that clogging occurs in the EGR passage, which may hinder the control of the EGR gas amount. In particular, when the EGR valve is fixed due to adhering unburned fuel to the EGR valve, it becomes impossible to control the amount of EGR gas, which may lead to instability of combustion and deterioration of exhaust gas characteristics. There is. Such a problem also occurs in the exhaust gas purifying apparatus of Patent Document 2. That is, if execution of the EGR operation is started immediately after the end of post injection for filter regeneration, unburned fuel returns to the intake system through the EGR passage together with exhaust gas, which may cause torque fluctuations and deterioration of exhaust gas characteristics. There is.

  The present invention has been made to solve the above-described problems, and is an internal combustion engine that can prevent torque fluctuations and exhaust gas characteristics from deteriorating immediately after the supply of unburned fuel is completed, and can ensure stable EGR operation. An object is to provide a control device.

JP 2000-38961 A JP 2001-280118 A

  In order to achieve the above object, the invention according to claim 1 is connected between an exhaust system (exhaust pipe 5) and an intake system (intake pipe 4) of an internal combustion engine, and a part of the exhaust gas is sucked from the exhaust system. An EGR passage (EGR pipe 14a) for refluxing the system as EGR gas, an EGR means (EGR control valve 14b) for refluxing the EGR gas via the EGR passage, and a connection portion provided in the exhaust system and connected to the EGR passage An exhaust gas purification device 20 disposed on the downstream side, an unburned fuel supply means (injector 6) for supplying unburned fuel so as to be contained in the exhaust gas in order to regenerate the exhaust gas purification device 20, and an unburned fuel EGR prohibiting means (ECU 2, step 7 in FIG. 3) for prohibiting execution of EGR by the EGR means until a predetermined time TMREF elapses from the end of the supply of unburned fuel by the fuel supply means. And wherein the door.

  According to this control apparatus for an internal combustion engine, a part of the exhaust gas is recirculated as EGR gas from the exhaust system to the intake system via the EGR passage by the EGR means. Thereby, the amount of NOx in the exhaust gas is reduced by lowering the combustion temperature. Further, the exhaust gas is purified by an exhaust gas purification device that is provided in the exhaust system and is disposed downstream of the connection portion with the EGR passage. Further, the unburned fuel is supplied by the unburned fuel supply means and included in the exhaust gas, whereby the exhaust gas purification device is regenerated.

  Further, the recirculation of the EGR gas to the intake system is prohibited by the EGR prohibiting means until a predetermined time has elapsed after the supply of unburned fuel is completed. As described above, since the start of the EGR operation is delayed at least by a predetermined time from the end of the supply of the unburned fuel, the unburned fuel is surely flowed downstream of the exhaust system until the predetermined time elapses. Thereafter, when the execution of the EGR operation is started, it is possible to sufficiently suppress the unburned fuel from returning to the intake system together with the EGR gas. As a result, the recirculation of the unburned fuel to the intake system and the rich air-fuel ratio resulting therefrom can be suppressed, so that it is possible to prevent torque fluctuations and exhaust gas characteristics from being deteriorated immediately after the supply of unburned fuel.

  In addition, since the amount of unburned fuel flowing through the EGR passage is reduced, it is possible to prevent the EGR valve from sticking when the EGR passage is formed by the adhesion of unburned fuel or when the EGR control means is constituted by an EGR valve. . Thereby, a stable EGR operation can be ensured, and stable combustion and good exhaust gas characteristics can be maintained.

  According to a second aspect of the present invention, in the control device for an internal combustion engine according to the first aspect, the exhaust gas purifying device has a filter 18 that collects particulates in the exhaust gas, and the particulates collected by the filter 18 Particulate amount detection means (ECU2, crank angle sensor 30, exhaust gas temperature sensor 33) for detecting the amount of PM (PM accumulated amount integrated value SDPFPMS), and the unburned fuel supply means is provided with the detected particulate amount. When larger than the fixed amount (threshold value PMREF), unburned fuel is supplied into the exhaust gas.

  According to this configuration, PM in the exhaust gas is collected by the filter provided on the downstream side of the EGR passage of the exhaust system. Further, when the amount of the collected PM detected by the particulate amount detection means becomes larger than a predetermined amount, the unburned fuel is supplied into the exhaust gas by the unburned fuel supply means, so that the filter Regenerates and recovers the PM collection ability of the filter. Further, the EGR operation is prohibited until a predetermined time elapses after the regeneration of the filter is completed and the supply of unburned fuel is stopped.

  As described above, the EGR operation is started after waiting for at least a predetermined time from the end of the regeneration operation of the filter. Therefore, even when the exhaust gas purification device has a filter for collecting PM, unburned fuel The filter can be regenerated by supplying the above and the effect of the invention according to claim 1 can be appropriately obtained.

  Hereinafter, an internal combustion engine control apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 schematically shows an internal combustion engine (hereinafter referred to as “engine”) 3 including a control device 1 to which the present invention is applied, an ECU 2 that controls the engine 3, and the like. The engine 3 is, for example, a 4-cylinder type diesel engine mounted on the vehicle V.

  A combustion chamber 3c is formed between the piston 3a of the engine 3 and the cylinder head 3b. An intake pipe 4 (intake system) and an exhaust pipe 5 (exhaust system) are connected to the cylinder head 3b, and a fuel injection valve (hereinafter referred to as “injector”) 6 (unburned fuel supply means) is connected to the combustion chamber. It is attached to face 3c.

  The injector 6 is disposed at the central portion of the top wall of the combustion chamber 3c, and is sequentially connected to a high-pressure pump 6a and a fuel tank (not shown) via a common rail (not shown). The fuel in the fuel tank is boosted to a high pressure by the high-pressure pump 6a, then sent to the injector 6 through the common rail, and injected from the injector 6 into the combustion chamber 3c. Further, the fuel injection amount QINJ and the injection timing of the injector 6 are determined by the ECU 2, and the valve opening time and valve opening timing of the injector 6 are obtained by the drive signal from the ECU 2 so that the determined fuel injection amount QINJ and the injection timing are obtained. Controlled.

  A magnet rotor 30a is attached to the crankshaft 3d of the engine 3. The magnet rotor 30a and the MRE pickup 30b constitute a crank angle sensor 30 (particulate amount detecting means). The crank angle sensor 30 outputs a CRK signal and a TDC signal, which are pulse signals, to the ECU 2 as the crankshaft 3d rotates (see FIG. 2).

  The CRK signal is output every predetermined crank angle (for example, 30 °). The ECU 2 obtains the rotational speed NE (hereinafter referred to as “engine rotational speed”) NE of the engine 3 based on the CRK signal. The TDC signal is a signal indicating that the piston 3a of each cylinder is at a predetermined crank angle position near the TDC (top dead center) at the start of the intake stroke, and in this example of the 4-cylinder type, every crank angle of 180 °. Is output.

  The intake pipe 4 is provided with a supercharging device 7. The supercharging device 7 includes a supercharger 8 constituted by a turbocharger, an actuator 9 connected thereto, and a vane opening control valve 10. I have.

  The supercharger 8 includes a rotatable compressor blade 8a provided in the intake pipe 4, a rotatable turbine blade 8b provided in the exhaust pipe 5, and a plurality of rotatable variable vanes 8c (only two are shown). And a shaft 8d for integrally connecting these blades 8a and 8b. The turbocharger 8 pressurizes the intake air in the intake pipe 4 by rotationally driving the compressor blade 8a integrated therewith as the turbine blade 8b is rotationally driven by the exhaust gas in the exhaust pipe 5. Perform supercharging operation.

  The actuator 9 is of a diaphragm type that is operated by negative pressure, and is mechanically connected to each variable vane 8c. A negative pressure is supplied to the actuator 9 from a negative pressure pump through a negative pressure supply passage (both not shown), and a vane opening degree control valve 10 is provided in the middle of the negative pressure supply passage. The vane opening control valve 10 is composed of an electromagnetic valve, and the negative pressure supplied to the actuator 9 changes when the opening is controlled by a drive signal from the ECU 2, and accordingly, the variable vane 8c The supercharging pressure is controlled by changing the opening degree.

  A water-cooled intercooler 11 and a throttle valve 12 are provided downstream from the supercharger 8 of the intake pipe 4 in order from the upstream side. The intercooler 11 cools the intake air when the temperature of the intake air rises due to the supercharging operation of the supercharging device 7 or the like. The throttle valve 12 is connected to an actuator 12a made of, for example, a DC motor. The opening degree of the throttle valve 12 is controlled by controlling the duty ratio of the current supplied to the actuator 12a by the ECU 2.

  Further, the intake manifold 4a of the intake pipe 4 is partitioned into a swirl passage 4b and a bypass passage 4c from the collecting portion to the branch portion, and each of the passages 4b and 4c is connected to each combustion chamber 3c via an intake port. Communicating with A swirl device 13 is provided in the bypass passage 4c. The swirl device 13 includes a swirl valve 13a, an actuator 13b for opening and closing the swirl valve 13a, and a swirl control valve 13c. By controlling the opening degree of the swirl control valve 13c by the ECU 2, the strength of the swirl generated in the combustion chamber 3c is controlled by changing the opening degree of the swirl valve 13a.

  The engine 3 is provided with an EGR device 14 having an EGR pipe 14a (EGR passage) and an EGR control valve 14b (EGR means). The EGR pipe 14 a is connected between the intake pipe 4 and the exhaust pipe 5, specifically, so as to connect the swirl passage 4 b of the collecting portion of the intake manifold 4 a and the upstream side of the supercharger 8 of the exhaust pipe 5. Has been. A part of the exhaust gas of the engine 3 is recirculated as EGR gas to the intake pipe 4 through the EGR pipe 14a, and the combustion temperature in the combustion chamber 3c is lowered by such an EGR operation, so that NOx in the exhaust gas is reduced. Is reduced.

  The EGR control valve 14b is composed of a linear electromagnetic valve attached to the EGR pipe 14a, and the valve lift amount is linearly controlled by a drive signal from the ECU 2 according to the load of the engine 3, The amount of EGR gas is controlled.

  Further, the EGR device 14 is provided with an EGR cooling device 15 for cooling the EGR gas, and the EGR cooling device 15 is located downstream of the EGR passage switching valve 15b and the EGR control valve 14b of the EGR pipe 14a. The EGR cooler 15c is provided. A bypass passage 15a is provided downstream of the EGR pipe 14a from the EGR control valve 14b so as to bypass the EGR cooler 15c, and the EGR passage switching valve 15b is attached to a branch portion of the bypass passage 15a. The EGR passage switching valve 15b selectively switches a portion of the EGR pipe 14a on the downstream side of the EGR passage switching valve 15b to the EGR cooler 15c side and the bypass passage 15a side under the control of the ECU 2.

  As described above, when the EGR passage switching valve 15b is switched to the bypass passage 15a side, the EGR gas passes through the bypass passage 15a and returns to the intake pipe 4. On the other hand, when switched to the reverse side, the EGR gas is cooled by the EGR cooler 15c and then returned to the intake pipe 4.

  Further, an exhaust gas purification device 20 is provided on the exhaust pipe 5 downstream of the supercharger 8. The exhaust gas purification device 20 includes an oxidation catalyst 17 and a filter 18 in order from the upstream side. The oxidation catalyst 17 oxidizes HC and CO in the exhaust gas and purifies the exhaust gas. The filter 18 collects particulates such as soot in the exhaust gas (hereinafter referred to as “PM”), thereby reducing PM discharged into the atmosphere. A catalyst (not shown) similar to the oxidation catalyst 17 is supported on the surface of the filter 18.

  Further, an exhaust gas temperature sensor 33 (particulate amount detection means) is provided immediately upstream of the filter 18 in the exhaust pipe 5. The exhaust gas temperature sensor 33 detects the temperature of the exhaust gas immediately upstream of the filter 18 (hereinafter referred to as “pre-filter gas temperature”) TDPFG, and outputs a detection signal to the ECU 2.

  Further, the ECU 2 outputs detection signals representing an operation amount (hereinafter referred to as “accelerator opening”) AP and a vehicle speed VP of an accelerator pedal (not shown) from the accelerator opening sensor 34 and the vehicle speed sensor 35, respectively.

  The ECU 2 is composed of a microcomputer including an I / O interface, CPU, RAM, ROM, and the like. The detection signals from the various sensors 30, 33 to 35 described above are each input to the CPU after A / D conversion and shaping by the I / O interface.

  In accordance with these input signals, the CPU determines the operating state of the engine 3 according to a control program stored in the ROM, etc., and executes a regeneration control process for regenerating the filter 18 according to the determined operating state. To do. In the present embodiment, the ECU 2 constitutes an EGR prohibition unit and a particulate amount detection unit.

  Next, the reproduction control process will be described with reference to FIG. This process is executed in synchronization with the input of the TDC signal. First, in step 1 (shown as “S1”, the same applies hereinafter), a DPFPMS per 1 TDC deposited on the filter 18, that is, a PM deposition amount (hereinafter referred to as “PM deposition amount”) for each combustion is calculated. Specifically, first, the PM emission amount discharged from the engine 3 is calculated by searching a PM emission amount map (not shown) according to the engine speed NE and the fuel injection amount QINJ. This PM emission map is obtained by experimenting the PM emission from the engine 3 and mapping the result according to the engine speed NE and the fuel injection amount QINJ. The fuel injection amount QINJ is calculated by searching a map (not shown) according to the engine speed NE and the accelerator pedal opening AP.

  Next, the amount of PM burned by the filter 18 is calculated by searching a table (not shown) based on the pre-filter gas temperature TDPFG. In this table, the PM combustion amount is set to a larger value as the pre-filter gas temperature TDPFG is higher. Then, the PM accumulation amount DPFPMS per 1 TDC is calculated by subtracting the PM combustion amount from the PM emission amount obtained as described above.

  Next, by adding the calculated PM accumulation amount DPFPMS to the PM accumulation amount accumulated value SDPFPMS obtained up to the previous time, the current PM accumulation amount accumulated value SDPFPMS (the amount of particulates collected by the filter) Is calculated (step 2). This PM accumulation amount integrated value SDPFPMS is reset to a value of 0 when the regeneration of the filter 18 is finished as will be described later, and therefore represents the amount of PM accumulated on the filter 18 at that time. .

  Next, it is determined whether or not a regeneration operation execution flag F_REON for regenerating the filter 18 is “1” (step 3). If the answer is NO and the reproducing operation is not being executed, it is determined whether or not the EGR delay flag F_EGRDLY is “1” (step 4). The EGR delay flag F_EGRDLY will be described later. When the answer is NO, it is determined whether or not the PM accumulation amount integrated value SDPFPMS calculated in step 2 is larger than a predetermined threshold value PMREF (for example, 9 g) (predetermined amount) for start determination (step). 5). If the answer is NO and SDPFPMS ≦ PMREF, the PM accumulation amount in the filter 18 is still small, so that the regeneration operation is not executed, and this processing is terminated.

  On the other hand, when the answer to step 5 is YES and the PM accumulation amount integrated value SDPFPMS becomes larger than the threshold value PMREF, it is assumed that the regenerating operation is executed, and the in-execution flag F_REON is set to “1” to indicate that. (Step 6). Thus, the reproduction operation is started by setting F_REON = “1”. This regeneration operation is performed by post injection in which fuel is injected into the combustion chamber 3c during the expansion stroke or exhaust stroke of the engine 3. Thereby, the unburned fuel is supplied into the exhaust gas, and the filter 18 is regenerated by burning the PM deposited on the filter 18 by controlling the filter 18 to a high temperature state (for example, 600 ° C.). In addition to this post-injection, it is also possible to perform control for decreasing the opening of the throttle valve 12 by controlling the actuator 12a, control for increasing the supercharging pressure by controlling the vane opening control valve 10, or the like.

  Next, the EGR prohibition flag F_EGRNG is set to “1”. (Step 7). As a result, the EGR operation is prohibited during the regeneration operation, and the EGR control valve 14b is controlled to the fully closed state, whereby the recirculation of the EGR gas to the intake pipe 4 is stopped. As a result, unburned fuel in the post-injected exhaust gas can be prevented from returning to the intake pipe 4 through the EGR pipe 14a together with the EGR gas.

  Subsequent to Step 7 or when the answer to Step 3 is YES and the reproduction operation is being executed, the process proceeds to Step 8. In step 8, it is determined whether the PM accumulation amount integrated value SDPFPMS is smaller than a threshold value PMSREF for termination determination. This threshold value is set to a small predetermined value close to the value 0. When this answer is NO and SDPFPMS ≧ PMSREF, the PM deposited on the filter 18 is not yet sufficiently burned, and the regeneration of the filter 18 is insufficient. Exit.

  On the other hand, when the answer to step 8 is YES and SDPFPMS <PMSREF, the regeneration operation is terminated assuming that the PM accumulated on the filter 18 is sufficiently combusted by the regeneration operation and the regeneration of the filter 18 is completed. In order to indicate this, the in-execution flag F_REON is reset to “0” (step 9), and the PM accumulation amount integrated value SDPFPMS is reset to 0 (step 10).

  Next, the timer value of the down-count delay timer DLYTM is set to a predetermined time TMREF (for example, 3 seconds) (step 11), and it is determined that the EGR operation start delay period after the end of the reproduction operation is in progress. In order to express this, the EGR delay flag F_EGRDLY is set to “1” (step 12), and this process is terminated. As a result of execution of step 12, the answer to step 4 becomes YES. In this case, the process proceeds to step 13.

  In step 13, it is determined whether or not the timer value of the delay timer DLYTM set in step 11 is 0. If the answer is NO and the predetermined time TMREF has not yet elapsed from the end of the reproduction operation, the process proceeds to step 5 and subsequent steps. On the other hand, if the answer to step 13 is YES and a predetermined time TMREF has elapsed after the end of the reproduction operation, the EGR prohibition flag F_EGRNG is set to “0” (step 14). Thereby, the prohibition of the EGR operation is canceled, and the EGR operation is controlled according to the operating state of the engine.

  Next, the EGR delay flag F_EGRDLY is reset to “0” (step 15), and then the process proceeds to step 5 and subsequent steps.

  FIG. 5 shows an operation example obtained by the reproduction control of this embodiment together with a comparative example. As shown in FIG. 5B, during the regeneration operation (before timing t1), the EGR control valve 14b is controlled to be fully closed, so that almost no unburned fuel is present in the EGR pipe 14a. Does not exist.

  When the regeneration operation ends (t1), in the comparative example, as indicated by a broken line in FIG. 5A, simultaneously with the end of the regeneration operation, the EGR control valve 14b is controlled from the fully closed state to the open state, and the EGR operation is performed. Start without delay. For this reason, as the unburned fuel by post injection remaining in the exhaust pipe 5 at the end of the regeneration operation flows into the EGR pipe 14a together with the EGR gas, as shown by the broken line in FIG. In addition, the amount of unburned fuel in the EGR pipe 14a suddenly increases and exceeds the upper limit value UPLIM. As a result, a large amount of unburned fuel is recirculated to the intake pipe 4 together with the EGR gas and is sucked into the combustion chamber 3c.

  On the other hand, in the present embodiment, as indicated by a solid line in FIG. 5A, when the predetermined time TMREF has elapsed after the end of the regeneration operation (t2), the EGR control valve 14b is controlled to be in the open state. The EGR operation is started. Thereby, the unburned fuel remaining in the exhaust pipe 5 during the predetermined time TMREF is sent to the downstream side oxidation catalyst 17 or the like. Therefore, as shown by the solid line in FIG. 5B, the amount of unburned fuel in the EGR pipe 14a increases after the start of the EGR operation, but is significantly suppressed as compared with the comparative example, and the upper limit value UPLIM Is well below.

  As described above, according to the present embodiment, at the end of the regeneration operation, the start of the EGR operation is delayed by the predetermined time TMREF, so that the unburned fuel supplied by the post-injection is passed by the predetermined time TMREF. It can be reliably sent to the oxidation catalyst 17 on the downstream side of the exhaust pipe 5, and after that, when the EGR operation is started, the unburned fuel is sufficiently prevented from returning to the intake pipe 4 together with the EGR gas. it can. As a result, the recirculation of unburned fuel to the intake pipe 4 and the enrichment of the air-fuel ratio resulting therefrom can be suppressed, so that torque fluctuations and exhaust gas characteristics deterioration immediately after the regeneration operation can be prevented.

  Further, since the amount of unburned fuel flowing through the EGR pipe 14a is reduced due to the delay of the start of the EGR operation, it is possible to prevent the EGR pipe 14a from being stuck and the EGR control valve 14b from sticking due to the adhesion of unburned fuel. . For the same reason, it is possible to prevent the bypass passage 15a from sticking to the EGR passage switching valve 15b. As described above, stable EGR operation can be secured, and stable combustion and good exhaust gas characteristics can be maintained.

  In addition, this invention can be implemented in various aspects, without being limited to the described embodiment. For example, in the embodiment, the unburned fuel is supplied into the exhaust gas by post-injection to the combustion chamber 3c using the injector 6, but the injector is separately provided upstream of the filter 18 of the exhaust pipe 5. It is also possible to inject fuel directly into the exhaust pipe 5.

  Further, in the embodiment, the PM accumulation amount integrated value SDPFPMS representing the PM accumulation amount in the filter 18 is calculated from the PM emission amount calculated based on the operating state of the engine 3 based on the pre-filter gas temperature TDPFG. The amount of PM deposition is calculated by subtracting the combustion amount and further integrating it, but the PM accumulation amount is detected by any other method, for example, by detecting the pressure difference between the upstream side and the downstream side of the filter 18. It may be calculated according to the pressure and the exhaust gas flow rate. Further, the PM deposition amount calculated in this way may be compared with the PM deposition amount integrated value SDPFPMS of the embodiment, and the larger one may be used as the PM deposition amount.

  Furthermore, although the embodiment is an example in which a filter is used as an exhaust gas purification device regenerated by supplying unburned fuel, a NOx catalyst may be used instead. The embodiment is an example in which the present invention is applied to a diesel engine. However, the present invention is not limited to this, and various engines other than a diesel engine, such as an outboard motor in which a gasoline engine and a crankshaft are arranged in a vertical direction, are used. It can also be applied to a marine vessel propulsion engine. In addition, it is possible to appropriately change the detailed configuration within the scope of the gist of the present invention.

It is a figure showing roughly an internal-combustion engine to which a control device by an embodiment is applied. It is a figure which shows roughly a part of control apparatus by embodiment. It is a part of flowchart of a reproduction | regeneration control process. It is a flowchart which shows the remaining part of the flowchart of FIG. It is a timing chart which shows the example of operation obtained by reproduction control of an embodiment with a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control apparatus 2 ECU (EGR prohibition means, particulate quantity detection means)
3 Internal combustion engine 4 Intake pipe (intake system)
5 Exhaust pipe (exhaust system)
6 Injector (unburned fuel supply means)
14a EGR pipe (EGR passage)
14b EGR control valve (EGR means)
18 Filter 20 Exhaust gas purifier 30 Crank angle sensor (Particulate amount detection means)
33 Exhaust gas temperature sensor (particulate amount detection means)
SDPFPMS PM accumulated amount integrated value (amount of particulates collected by the filter)
PMREF threshold (predetermined amount)

Claims (2)

An EGR passage connected between the exhaust system and the intake system of the internal combustion engine, for recirculating a part of the exhaust gas from the exhaust system to the intake system as EGR gas;
EGR means for recirculating EGR gas via the EGR passage,
An exhaust gas purifying device provided in the exhaust system and disposed downstream of a connection portion with the EGR passage;
In order to regenerate the exhaust gas purification device, unburned fuel supply means for supplying unburned fuel so as to be included in the exhaust gas,
EGR prohibiting means for prohibiting execution of EGR by the EGR means until a predetermined time has elapsed from the end of the supply of unburned fuel by the unburned fuel supply means;
A control device for an internal combustion engine, comprising: The exhaust gas purification apparatus has a filter that collects particulates in the exhaust gas,
It further comprises a particulate amount detection means for detecting the amount of particulates collected by the filter,
The control apparatus for an internal combustion engine according to claim 1, wherein the unburned fuel supply means supplies unburned fuel into the exhaust gas when the detected particulate amount is larger than a predetermined amount.

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