JP5282056B2 - Internal combustion engine - Google Patents

Description

  The present invention relates to an internal combustion engine, and more particularly, to an internal combustion engine having two banks and having an exhaust system for each bank.

  In a large displacement V-type engine, if the intake system is integrated into one system, for example, the intake amount is controlled by a single intake throttle with a large diameter, so the accuracy deteriorates, and if the exhaust system is integrated into one system. Since only one catalyst or exhaust purification device is provided, there is a problem in that the capacity thereof becomes large and the vehicle mountability deteriorates. Such a problem can be avoided by dividing the intake / exhaust system into two systems for each bank.

  In such an engine, for each of the actuators arranged for each bank, such as an EGR valve, both of which a separate control target value is set (independent control) and one of which the same control target value is set (simultaneous control) The technology is known. Patent Document 1 describes a control that employs the latter technique for a V-type diesel engine. Compared to the case where independent control is performed for each bank as in the former technique, the load in the calculation of the ECU is reduced. There is an advantage that becomes smaller.

  In recent diesel engines, a diesel particulate filter (DPF) (including a catalyst) is mounted on the exhaust path as an exhaust purification device, and the particulate matter (PM) contained in the exhaust gas is captured by the DPF. Gather. The degree of clogging of PM is estimated by measuring the differential pressure before and after the DPF. When the amount of collected PM reaches a certain value, regeneration control for incinerating PM is executed.

  By the way, PM contains soluble organic components (SOF) in addition to soot (carbon). Both soot and SOF are incinerated by the temperature rise of the catalyst by DPF regeneration control, but the trapped amount of soot, which is a solid component, is easily reflected in the differential pressure before and after the DPF, whereas the trapped amount of SOF is Difficult to be reflected in differential pressure. For this reason, it is impossible to accurately determine whether or not the amount of collected SOF exceeds a certain value only by regeneration control based on differential pressure, so that the amount of collected SOF is a certain value. However, there is a possibility that the DPF is not regenerated despite being over the range. In this case, the SOF may flow out downstream of the DPF and cause white smoke. Therefore, the amount of SOF collected in the DPF is estimated, and when the estimated amount exceeds a certain amount that can be collected, regeneration control of the DPF is performed or the EGR amount is changed according to the estimated amount ( By subtracting correction), it is necessary to adjust the amount of discharged SOF so that SOF does not accumulate in the DPF over a certain amount.

  The amount of SOF discharged is adjusted by controlling the EGR rate. When the EGR amount is increased, the combustion temperature in the combustion chamber is lowered, so that the amount of nitrogen oxide (NOx) produced decreases, but PM increases. In addition, the lower the combustion temperature, the greater the amount of SOF that is a soluble component in PM, compared to soot that is a solid in PM. Conversely, the amount of SOF generated in PM can be reduced by reducing the EGR amount and raising the combustion temperature.

JP 2007-21646 A

  However, in an engine having two exhaust systems for each bank, the amount of SOF generated varies from bank to bank, so there is a measure to reduce the amount of SOF generated compared to an engine with a single exhaust system. It becomes difficult.

  The present invention has been made to solve such problems. In an engine having two exhaust systems for each bank, control is performed so that the left and right EGR valve openings are the same (simultaneous control). Thus, an object of the present invention is to provide an internal combustion engine capable of preventing the generation of white smoke due to the outflow of SOF while suppressing the calculation load of the ECU.

The internal combustion engine according to the present invention has two banks, and each bank includes an exhaust pipe, an intake pipe provided with at least a merge portion where intake air of each bank merges, and an intake pipe upstream of the exhaust pipe and the merge portion. An internal combustion engine having a communicating EGR passage, an EGR valve for adjusting the amount of EGR gas flowing through the EGR passage, and a DPF provided in each exhaust pipe, the internal combustion engine being provided in each exhaust pipe, An exhaust gas temperature detecting means for detecting the temperature of the exhaust gas flowing through the pipe, and a control device for detecting the number of revolutions of the internal combustion engine and the amount of fuel injected into a cylinder provided in the bank; Calculates the amount of SOF adsorbed on each DPF for each fuel injection from the temperature of the exhaust gas flowing through each exhaust pipe, the number of revolutions, and the fuel injection amount. Cumulatively for each DPF Calculating a product SOF adsorption amount, to calculate the EGR ratio from the cumulative SOF adsorption amount, and controls the opening degrees of the EGR valve to the same degree on the basis of the calculated EGR rate. By calculating the EGR rate of the entire engine from the accumulated adsorption amount of each DPF, it is possible to calculate the EGR rate in consideration of the variation in the SOF generation amount for each bank, and it is possible to control each EGR valve at the same opening.
The control device may calculate an average value of the accumulated SOF adsorption amount of each DPF and calculate the EGR rate from the average value.
The control device may calculate the EGR rate from the larger value of the accumulated SOF adsorption amounts of the respective DPFs.
The control device includes: first calculation means for specifying the SOF increase amount of each DPF from the rotation speed, the fuel injection amount, and the temperature of the exhaust gas flowing through each exhaust pipe; and the exhaust gas flowing through the exhaust pipe of each bank Second calculation means for specifying the SOF reduction amount of each DPF from the temperature of the DPF, third calculation means for specifying the target EGR rate from the rotation speed and the fuel injection amount, the rotation speed, the fuel injection amount, and the average value And a fourth calculating means for identifying the corrected EGR rate from the SOF, calculating the SOF adsorption amount by subtracting the SOF decrease amount from the SOF increase amount, and calculating the EGR rate by subtracting the corrected EGR rate from the target EGR rate. May be.
The control device includes: first calculation means for specifying the SOF increase amount of each DPF from the rotation speed, the fuel injection amount, and the temperature of the exhaust gas flowing through each exhaust pipe; and the exhaust gas flowing through the exhaust pipe of each bank Second calculation means for specifying the SOF decrease amount of each DPF from the temperature of the DPF, third calculation means for specifying the target EGR rate from the rotation speed and the fuel injection amount, the rotation speed, the fuel injection amount, and each DPF And calculating a SOF adsorption amount by subtracting the SOF decrease amount from the SOF increase amount, and calculating the SOF adsorption amount from the target EGR rate. The EGR rate may be calculated by subtracting the corrected EGR rate.
Each EGR passage may be provided with an EGR valve, and the control device may control the opening degree based on the EGR rate so that the opening degree of each EGR valve becomes the same.

  According to the present invention, in an engine having two exhaust systems for each bank, it is possible to calculate the EGR rate in consideration of the variation in the amount of SOF generated for each bank while suppressing the calculation load of the ECU. The generation of white smoke due to the outflow of water can be prevented.

1 is a configuration diagram of an internal combustion engine according to an embodiment of the present invention. It is a 1st map which specifies SOF reduction amount from the temperature of exhaust gas. It is a 2nd map which specifies SOF increase amount from rotation speed and fuel injection amount. It is a 3rd map which specifies the correction coefficient of the SOF increase amount from the temperature of exhaust gas. It is a 4th map which specifies a target EGR rate from number of rotations and fuel injection quantity. It is a 5th map which specifies EGR rate reduction amount from rotation speed and fuel injection quantity. It is a 6th map which specifies the correction coefficient of adsorption amount from adsorption amount.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
An internal combustion engine according to an embodiment of the present invention is shown in FIG. The diesel engine 1 which is an internal combustion engine includes a first bank 2 and four cylinders 3a (only one is shown in FIG. 1) provided with four cylinders 2a (only one is shown in FIG. 1). V-type 8-cylinder diesel engine having two banks of the second bank 3 provided. The first bank 2 includes an intake pipe 4 and an exhaust pipe 5, and the second bank 3 includes an intake pipe 6 and an exhaust pipe 7. The intake pipes 4 and 6 merge on the upstream side to constitute one intake merge pipe 8, and an air cleaner 9 is provided in the intake merge pipe 8. The intake pipes 4 and 6 have intake manifolds 11 and 12 that communicate with the cylinders 2 a and 3 a of the first bank 2 and the second bank 3, respectively, and merge at the upstream side of the intake manifolds 11 and 12. The confluence 13 is formed. Diesel throttles 14 and 15 are provided in the intake pipes 4 and 6, respectively, upstream of the junction 13.

  The cylinders 2a and 3a are respectively provided with pistons 41 and 42 capable of reciprocating in the cylinders 2a and 3a. The pistons 41 and 42 are connected to the crankshaft 45 via connecting rods 43 and 44, respectively.

  The exhaust pipes 5 and 7 are independent from each other, and are provided with exhaust manifolds 16 and 17 communicating with the cylinders 2a and 3a, respectively. The exhaust manifolds 16 and 17 each have injectors 18 and 19 for adding fuel to the exhaust gas. Is provided. The exhaust pipes 5 and 7 are provided with oxidation catalysts 21 and 23, respectively, and DPFs 22 and 24 are provided downstream of the oxidation catalysts 21 and 23, respectively. Further, the exhaust pipes 5 and 7 are provided with temperature sensors 25 and 26 which are exhaust gas temperature detecting means for detecting the temperature of the exhaust gas upstream of the oxidation catalysts 21 and 23, respectively. Differential pressure sensors 27 and 28 for measuring the differential pressure are provided.

  The diesel engine 1 includes turbos 31 and 32, and the turbo 31 includes a compressor 31 a provided in the intake pipe 4 and a turbine 31 b provided in the exhaust pipe 5, and the turbo 32 is provided in the intake pipe 6. The compressor 32a and the turbine 32b provided in the exhaust pipe 7 are comprised. Intercoolers 37 and 38 are provided between the compressor 31a and the diesel throttle 14 and between the compressor 32a and the diesel throttle 15, respectively. Further, the diesel engine 1 includes EGR passages 33 and 34 that connect the intake pipes 4 and 6 and the exhaust pipes 5 and 7, respectively. The EGR passages 33 and 34 are provided with EGR valves 35 and 36, respectively. .

  Furthermore, the diesel engine 1 includes an ECU 30 that is a control device, and the ECU 30 is electrically connected to the injectors 18 and 19, the temperature sensors 25 and 26, the differential pressure sensors 27 and 28, and the EGR valves 35 and 36. At the same time, the rotational speed of the diesel engine 1 and the fuel injection amount injected into each of the cylinders 2a and 3a are detected. Further, in the diesel engine 1, a first map that specifies the SOF decrease amount from the exhaust gas temperature shown in FIG. 2 and a first map that specifies the SOF increase amount from the rotation speed and the fuel injection amount shown in FIG. 4, a third map for specifying the correction coefficient for the SOF increase amount from the exhaust gas temperature shown in FIG. 4, and a fourth map for specifying the target EGR rate from the rotational speed and the fuel injection amount shown in FIG. 5. A map, a fifth map for specifying the EGR rate decrease amount from the rotation speed and the fuel injection amount, and a sixth map for specifying a correction coefficient for the adsorption amount from the adsorption amount shown in FIG. Built in. In this embodiment, the second map and the third map are the first calculation means, the first map is the second calculation means, the fourth map is the third calculation means, and the fifth map and the sixth map are the fourth calculation means. It corresponds to.

Next, the operation of the internal combustion engine according to this embodiment will be described.
When the diesel engine 1 is operated, the air flowing through the intake merging pipe 8 is divided into two parts after the dust and the like are removed by the air cleaner 9, and flows through the intake pipes 4 and 6, respectively. The air flowing through the intake pipes 4 and 6 is compressed by the compressors 31a and 32a of the turbo 31 and 32, cooled by the intercoolers 37 and 38, and the flow rate is adjusted by the diesel throttles 14 and 15. Thereafter, the air flowing through each of the intake pipes 4 and 6 once merges at the junction 13, then divides into two again and is sucked into the cylinders 2 a and 3 a via the intake manifolds 11 and 12. . Note that exhaust gas is mixed as EGR gas into the air flowing through the intake pipes 4 and 6 through the EGR passages 33 and 34 as necessary. The amount of EGR gas is adjusted by controlling the opening degree of the EGR valves 35 and 36 so that the EGR rate representing the amount of EGR gas with respect to the amount of intake air flowing into the cylinders 2a and 3a becomes the target EGR rate. . In addition, due to individual differences such as diesel throttles 14 and 15, turbo 31 and 32, EGR valves 35 and 36, etc. arranged for each bank, in each of the intake pipes 4 and 6, each bank has an intake air amount, a supercharging pressure, Even when the EGR rate is set to the same target value, these values may be different. However, since they are merged once at the merge section 13, the flow rate of air sucked into the cylinders 2a and 3a from the intake manifolds 11 and 12, the supercharging pressure, and the EGR rate can be made the same. Therefore, each bank can be controlled simultaneously in supercharging pressure control and EGR rate control.

  Air sucked into the cylinders 2a and 3a is compressed by the pistons 41 and 42, respectively, and fuel is injected from an injector (not shown) to cause combustion in the cylinders 2a and 3a. Due to this combustion, the pistons 41 and 42 reciprocate in the cylinders 2a and 3a, and the reciprocating motion is converted into the rotational motion of the crankshaft 45 via the connecting rods 43 and 44, and output from the diesel engine 1 is obtained. .

  Exhaust gases generated by combustion in the cylinders 2a and 3a are exhausted to the exhaust manifolds 16 and 17, respectively, and flow through the exhaust pipes 5 and 7. The exhaust gas flowing through the exhaust pipes 5 and 7 rotates the turbines 31b and 32b of the turbo 31 and 32, respectively, whereby the compressors 31a and 32a rotate. The exhaust gas is released into the atmosphere after the PM is removed in the DPFs 22 and 24.

  When the amount of PM collected in the DPFs 22 and 24 increases, the differential pressure between the upstream side and the downstream side of the DPFs 22 and 24 increases. These differential pressures are detected by differential pressure sensors 27 and 28, and the detected values are sent to the ECU 30. When the value detected by the differential pressure sensors 27 and 28 becomes larger than the upper limit value stored in advance in the ECU 30, the ECU 30 regenerates the DPF whose differential pressure is larger than the upper limit value.

  As a description of the DPF regeneration operation, a case where the DPF 22 is regenerated will be described. The same applies to the regeneration operation of the DPF 24. The ECU 30 operates the injector 18 to add fuel to the exhaust gas exhausted from each cylinder 2a. The added fuel flows into the oxidation catalyst 21 along with the exhaust gas, and an oxidation reaction occurs due to the catalytic function of the oxidation catalyst 21. The exhaust gas temperature rises due to reaction heat due to this oxidation reaction. When the exhaust gas whose temperature has risen flows into the DPF 22, the PM collected by the DPF 22 is burned and removed from the DPF 22 by the heat of the exhaust gas. When the detected value of the differential pressure sensor 27 decreases to the lower limit value stored in advance in the ECU 30, the ECU 30 stops the operation of the injector 18 in order to end the regeneration of the DPF 22.

  However, as already described, since the amount of SOF collected is less likely to be reflected in the differential pressure, the amount of SOF collected may already exceed a certain value before starting the regeneration of the DPF. SOF flows downstream of the DPF and causes white smoke. Therefore, every time fuel is injected into each cylinder 2a and 3a, the amount of SOF collected by each DPF 22 and 24 (cumulative SOF adsorption amount) is calculated by performing calculation according to the method described below. The EGR rate is adjusted based on the calculated value.

First, when fuel is injected into one of the cylinders 2a and 3a, the ECU 30 receives data (T [° C.]) detected by the temperature sensors 25 and 26, and based on the first map shown in FIG. The SOF reduction amount (a [mg / sec]) of the SOF discharged from the bank corresponding to the cylinder into which the fuel is injected is specified. Here, the SOF reduction amount is an amount by which the SOF collected in the DPF of each bank is incinerated and removed by the heat of the exhaust gas. Next, the ECU 30 includes data on the rotational speed of the diesel engine 1 (b [rpm]), data on the fuel injection amount injected into one of the cylinders 2a and 3a (c ₁ [mm ³ / st]), and And the SOF increase amount (d [mg / sec]) of the SOF discharged from the corresponding bank is specified based on the second map shown in FIG. Here, the SOF increase amount means a basic SOF discharge amount obtained from the amount of fuel injected into the cylinder and the rotational speed. FIG. 3 shows the relationship between the rotational speed and the SOF increase amount for three fuel injection amounts c ₁ , c ₂ , c ₃ (c ₁ <c ₂ <c ₃ ). It is not limited to the case where only the fuel injection amount is illustrated, and it is preferable that the relationship between the rotational speed and the SOF increase amount is satisfied for a large number of fuel injection amounts. The same applies to FIGS. 5 and 6 described below. Further, the ECU 30 specifies the correction coefficient (e [−]) for the SOF increase amount from the data (T [° C.]) detected by the temperature sensors 25 and 26 based on the third map shown in FIG. . Here, since the SOF is in a liquid state, the SOF increase correction coefficient is such that when the exhaust gas temperature rises, the moisture in the SOF easily evaporates, so even if the SOF is discharged from each bank, the exhaust gas is exhausted. This is for considering that a part of the discharged SOF becomes a solid soot as the gas temperature is higher and the liquid SOF decreases.

The ECU 30 multiplies the SOF increase amount (d [mg / sec]) specified based on the second map by the correction coefficient (e [−]) specified based on the third map, thereby correcting the SOF. The increase amount (d × e [mg / sec]) is calculated. The correction SOF increase amount is not limited to the second map and the third map as long as it is a map for obtaining the increase amount of SOF newly collected in the DPF from the rotation speed, the fuel injection amount, and the exhaust gas temperature. There may be two maps. Further, the ECU 30 subtracts the SOF decrease amount from the corrected SOF increase amount to calculate the SOF adsorption amount adsorbed on the DPF provided in the exhaust pipe of the corresponding bank ((d × ea) [mg / sec]). The ECU 30 performs this operation every time fuel is injected into one of the cylinders 2a and 3a, thereby calculating the amount of SOF adsorbed to each of the DPFs 22 and 24, and the calculated SOF adsorption. The amount is accumulated, and the accumulated SOF adsorption amounts (f ₁ and f ₂ [mg]) of the DPFs 22 and 24 are calculated.

Next, the ECU 30 calculates the EGR rate from the calculated accumulated SOF adsorption amount by the following method.
First, the ECU 30 is shown in FIG. 5 from the rotational speed (b [rpm]) of the diesel engine 1 and the fuel injection amount (c ₁ [mm ³ / st]) injected into one of the cylinders 2a and 3a. A target EGR rate (g _tar [−]) is specified based on the fourth map. Here, the target EGR rate is an EGR rate for optimally reducing the NOx discharged from the diesel engine 1, and does not consider the suppression of SOF. Next, the ECU 30 is shown in FIG. 6 from the rotational speed (b [rpm]) of the diesel engine 1 and the fuel injection amount (c ₁ [mm ³ / st]) injected into each cylinder 2a and 3a. Based on the fifth map, the EGR rate decrease amount (Δg [−]) is specified. Here, the amount of EGR rate reduction refers to the suppression of SOF from the target EGR rate that does not consider SOF suppression so that the amount of NOx generated does not exceed a certain value even if the EGR amount is reduced. This means the maximum value of the EGR rate to be subtracted. Further, the ECU 30 calculates an average value (f _av = (f ₁ + f ₂ ) / 2) by adding the accumulated SOF adsorption amounts of the DPFs 22 and 24 at that time and dividing by two, as shown in FIG. Based on the sixth map, the SOF adsorption amount correction coefficient (h [-]) is specified. This correction coefficient is calculated based on the saturation amount Xs of the accumulated SOF adsorption amount (in this embodiment, the average value f _av of the accumulated SOF adsorption amounts of the DPFs 22 and 24) (if the adsorption amount further increases, the SOF becomes downstream of the DPF). (Meaning the limit amount that flows out)), the smaller the cumulative SOF adsorption amount, the smaller the value. This is to reduce the EGR rate decrease amount subtracted from the target EGR rate in order to change the EGR rate resulting from the SOF generation amount based on the amount of SOF that can be adsorbed to the DPF.

From the target EGR rate (g _tar [−]) specified based on the fourth map, the ECU 30 determines the EGR rate reduction amount (Δg [−]) specified based on the fifth map and the sixth map. The EGR rate is calculated by subtracting the product of the identified correction coefficient (h [−]) (g _tar −h × Δg). The ECU 30 adjusts the opening degree based on the calculated EGR rate so that the opening degree of the EGR valves 35 and 36 becomes the same. If the corrected EGR reduction amount is a map for obtaining the EGR rate to be subtracted from the rotational speed, the fuel injection amount, and the cumulative SOF adsorption amount (average value of the cumulative SOF adsorption amount of each DPF), the fifth map and Not only the sixth map, but one map may be used.
The above operation is repeated each time fuel is injected into each of the cylinders 2a and 3a.

In this way, in the V-type 8-cylinder diesel engine 1 in which the first bank 2 and the second bank 3 are each provided with the exhaust pipes 5 and 7, the variation in the amount of SOF generated in the first bank 2 and the second bank 3 is different. Therefore, it is possible to prevent the generation of white smoke due to the outflow of SOF.
Further, the average value of the accumulated SOF adsorption amounts of the DPFs 22 and 24 is calculated, and the EGR rate is calculated by specifying the correction coefficient of the adsorption amount from the average value based on the sixth map. It is also possible to suppress NOx generation while preventing it.
Further, based on the EGR rate calculated using the average value of the accumulated adsorption amounts of the DPFs 22 and 24, the opening degree of each EGR valve 35 and 36 is controlled so that the opening degree of each EGR valve 35 and 36 becomes the same. Therefore, the control is simplified as compared with the case where the opening degrees of the EGR valves 35 and 36 are separately controlled, and the calculation burden on the ECU 30 can be reduced.

In this embodiment, when the correction coefficient for the SOF adsorption amount is specified based on the sixth map, the average value f _av of the accumulated adsorption amounts of the DPFs 22 and 24 is used. However, the present invention is not limited to this embodiment. Absent. The correction coefficient may be specified using the larger value of the accumulated adsorption amounts (f ₁ and f ₂ ) of the DPFs 22 and 24. Thereby, although optimization of suppression of NOx generation becomes incomplete, generation of white smoke can be surely prevented.

  In this embodiment, the V-type 8-cylinder diesel engine 1 has been described as an example of the internal combustion engine, but the present invention is not limited to this. As long as it has two banks, each bank has an exhaust system, a confluence where the intake system merges at least once is provided, and the EGR passage is connected at the confluence of the intake system or upstream of the confluence Any type of internal combustion engine or horizontally opposed engine may be used. Further, the number of cylinders in each bank is not limited to eight, and any number of cylinders may be provided.

  In this embodiment, the temperature sensors 25 and 26, which are exhaust gas temperature detection means for detecting the temperature of the exhaust gas, are provided upstream of the oxidation catalysts 21 and 23. However, the present invention is not limited to this. In order to detect the temperature of the exhaust gas flowing into the DPF, it may be arranged upstream of the DPF or downstream of the DPF.

  In this embodiment, the exhaust gas temperature is determined using the values of the temperature sensors 25 and 26 that are exhaust gas temperature detection means to identify the correction coefficient for the increase amount of SOF in each bank, and the correction SOF amount is calculated. It is not limited to this. For example, the corrected SOF increase amount may be calculated from the average or minimum value of the temperature sensors in each bank.

  DESCRIPTION OF SYMBOLS 1 Diesel engine (internal combustion engine), 2 1st bank, 3 2nd bank, 4,6 Intake pipe, 5,7 Exhaust pipe, 13 Junction part, 22,24 DPF, 25,26 Temperature sensor (Exhaust gas temperature detection means) ), 30 ECU (control device), 33, 34 EGR passage, 35, 36 EGR valve.

Claims (6)

Each bank has an exhaust pipe, an intake pipe having a merging portion where at least the intake air of each bank merges, an EGR passage communicating with the exhaust pipe and an intake pipe upstream of the merging portion, An internal combustion engine having an EGR valve that adjusts the amount of EGR gas flowing through the EGR passage, and a DPF provided in each exhaust pipe,
The internal combustion engine
An exhaust gas temperature detecting means provided in each exhaust pipe for detecting the temperature of the exhaust gas flowing through each exhaust pipe;
A controller for detecting the number of revolutions of the internal combustion engine and the amount of fuel injected into a cylinder provided in the bank;
The control device calculates an adsorption amount of SOF adsorbed on each DPF for each fuel injection from the temperature of the exhaust gas flowing through each exhaust pipe, the rotation speed, and the fuel injection amount. The accumulated SOF adsorption amount is accumulated to calculate the accumulated SOF adsorption amount of each DPF, the EGR rate is calculated from the accumulated SOF adsorption amount, and each EGR valve opening degree is controlled to the same opening degree based on the calculated EGR rate. An internal combustion engine.   The internal combustion engine according to claim 1, wherein the control device calculates an average value of accumulated SOF adsorption amounts of the respective DPFs, and calculates the EGR rate from the average value.   2. The internal combustion engine according to claim 1, wherein the control device calculates the EGR rate from a larger value of accumulated SOF adsorption amounts of the respective DPFs. The controller is
First calculation means for specifying the SOF increase amount of each DPF from the rotational speed, the fuel injection amount, and the temperature of the exhaust gas flowing through each exhaust pipe;
Second calculation means for specifying the SOF reduction amount of each DPF from the temperature of the exhaust gas flowing through the exhaust pipe of each bank;
Third calculation means for specifying a target EGR rate from the rotation speed and the fuel injection amount;
Fourth calculating means for specifying a corrected EGR rate from the rotation speed, the fuel injection amount, and the average value;
Calculate the SOF adsorption amount by subtracting the SOF decrease amount from the SOF increase amount,
The internal combustion engine according to claim 2, wherein the EGR rate is calculated by subtracting the corrected EGR rate from the target EGR rate. The controller is
First calculation means for specifying the SOF increase amount of each DPF from the rotational speed, the fuel injection amount, and the temperature of the exhaust gas flowing through each exhaust pipe;
Second calculation means for specifying the SOF reduction amount of each DPF from the temperature of the exhaust gas flowing through the exhaust pipe of each bank;
Third calculation means for specifying a target EGR rate from the rotation speed and the fuel injection amount;
Fourth calculating means for specifying a corrected EGR rate from the rotation speed, the fuel injection amount, and the larger value of the accumulated SOF adsorption amounts of the DPFs,
Calculate the SOF adsorption amount by subtracting the SOF decrease amount from the SOF increase amount,
The internal combustion engine according to claim 3, wherein the EGR rate is calculated by subtracting the corrected EGR rate from the target EGR rate. Each EGR passage is provided with an EGR valve,
The internal combustion engine according to any one of claims 1 to 5, wherein the control device controls the opening degree of each EGR valve based on the EGR rate so that the opening degree of each EGR valve becomes the same.

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