JP2019173741A - Exhaust gas purifying and regenerating device - Google Patents

Abstract

An exhaust gas purifying unit is regenerated with a simple configuration.
An exhaust gas purification / regeneration apparatus includes an air bypass passage that communicates an upstream side and a downstream side of a compressor provided in an intake passage, and an air bypass valve that opens and closes the air bypass passage. Based on the drive state of the air bypass valve, the branch flow path 206 that branches from the air bypass flow path and communicates with the exhaust flow path 46 having the exhaust gas purification unit 70, the branch valve 208 that opens and closes the branch flow path, A branch valve control unit for controlling the opening of the branch valve.
[Selection] Figure 1

Description

  The present invention relates to an exhaust gas purification / regeneration device.

  In Patent Document 1, when the temperature of an exhaust gas purification unit (for example, a catalyst) provided in the exhaust flow path is equal to or lower than a target temperature, the supercharger is driven and the exhaust flow from the intake flow path through the EGR flow path. There is disclosed an exhaust gas purification / regeneration device that supplies air to a road and raises the temperature of an exhaust gas purification unit.

JP 2007-332925 A

  However, in Patent Document 1, in order to supply air from the intake passage to the exhaust passage via the EGR passage, it is necessary to make the intake pressure higher than the exhaust pressure, and the compressor of the supercharger is driven to rotate. It was necessary to install an electric motor. Therefore, in patent document 1, there existed a problem that the structure of the exhaust gas purification reproduction | regeneration apparatus which reproduces | regenerates an exhaust gas purification part became complicated.

  Therefore, an object of the present invention is to provide an exhaust gas purification / regeneration device that can regenerate an exhaust gas purification unit with a simple configuration.

  In order to solve the above-described problems, an exhaust gas purification / regeneration apparatus according to the present invention includes an air bypass passage that connects an upstream side and a downstream side of a compressor provided in an intake passage, and an air that opens and closes the air bypass passage. Based on a bypass valve, a branch passage that branches from the air bypass passage and communicates with an exhaust passage having an exhaust gas purification unit, a branch valve that opens and closes the branch passage, and a driving state of the air bypass valve And a controller for controlling the opening degree of the branch valve.

  The control unit controls the branch valve to an open state when the air bypass valve is in an open state, and controls the branch valve to be closed when the air bypass valve is in a closed state. Good.

  The control unit may control the opening degree of the branch valve according to an air-fuel ratio determined according to an engine load.

  The control unit controls the branch valve to an open state when the air-fuel ratio is a stoichiometric air-fuel ratio or rich and the air bypass valve is open, and the air-fuel ratio is lean or the air bypass The branch valve may be controlled to be closed when the valve is closed.

  According to the present invention, the exhaust gas purification unit can be regenerated with a simple configuration.

It is the schematic which shows the structure of the engine system of this embodiment. It is a figure which shows the flowchart of the regeneration process of GPF by a branch valve control part.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  FIG. 1 is a schematic diagram showing a configuration of an engine system 100 of the present embodiment. In FIG. 1, the signal flow is indicated by broken arrows. As shown in FIG. 1, the engine system 100 includes an engine 102 and an ECU (Engine Control Unit) 104. The ECU 104 is configured by a microcomputer including a central processing unit (CPU), a ROM that stores programs, a RAM as a work area, and the like, and performs overall control of the entire engine 102. However, the configuration and processing related to the present embodiment will be described in detail below, and the description of the configuration and processing unrelated to the present embodiment will be omitted.

  The engine 102 includes a cylinder block 10, a crankcase 12 formed integrally with the cylinder block 10, and a cylinder head 14 connected to the cylinder block 10.

  A plurality of cylinders 16 are formed in the cylinder block 10, and a piston 18 is slidably supported by the connecting rod 20 on the cylinder 16. A space surrounded by the cylinder head 14, the cylinder 16, and the crown surface of the piston 18 is formed as the combustion chamber 22.

  Further, the engine 102 has a crankcase 24 formed by the crankcase 12, and a crankshaft 26 is rotatably supported in the crankcase 24. The piston 18 is connected to the crankshaft 26 via the connecting rod 20.

  An intake port 28 and an exhaust port 30 are formed in the cylinder head 14 so as to communicate with the combustion chamber 22.

  An intake passage 34 including an intake manifold 32 is connected to the intake port 28. The intake port 28 is formed with one opening on the upstream side of the intake air facing the intake manifold 32. The intake port 28 has two openings formed on the downstream side facing the combustion chamber 22. As a result, the intake port 28 is divided into two flow paths on the way from upstream to downstream. The intake port 28 communicates with the intake manifold 32 on the upstream side of intake air, and communicates with each cylinder 16 on the downstream side of intake air. An intake passage 34 communicates with the collecting portion of the intake manifold 32.

  A tip (umbrella) of the intake valve 36 is located between the intake port 28 and the combustion chamber 22. A cam 42 fixed to the intake camshaft 40 is in contact with the end of the intake valve 36 via a rocker arm 38. The intake valve 36 opens and closes the intake port 28 relative to the combustion chamber 22 as the intake camshaft 40 rotates.

  An exhaust passage 46 including an exhaust manifold 44 is connected to the exhaust port 30. The exhaust port 30 has two openings formed on the upstream side of the exhaust facing the combustion chamber 22. The exhaust port 30 is formed with one opening on the downstream side facing the exhaust manifold 44. As a result, the exhaust port 30 is integrated into one flow path on the way from upstream to downstream. The exhaust port 30 communicates with each cylinder 16 on the upstream side of the exhaust, and communicates with the exhaust manifold 44 on the downstream side of the exhaust. An exhaust passage 46 communicates with the gathering portion of the exhaust manifold 44.

  A front end (umbrella) of the exhaust valve 48 is located between the exhaust port 30 and the combustion chamber 22. A cam 54 fixed to the exhaust camshaft 52 is in contact with the end of the exhaust valve 48 via a rocker arm 50. The exhaust valve 48 opens and closes the exhaust port 30 with respect to the combustion chamber 22 as the exhaust camshaft 52 rotates.

  Further, the cylinder head 14 is provided with an injector 56 and a spark plug 58 so that the tip thereof is located in the combustion chamber 22. The injector 56 injects fuel into the combustion chamber 22. The spark plug 58 ignites and burns an air-fuel mixture of air that has flowed into the combustion chamber 22 via the intake port 28 and fuel injected from the injector 56 at a predetermined timing. Due to such combustion, the piston 18 reciprocates in the cylinder 16. The crankshaft 26 rotates through the connecting rod 20 as the piston 18 reciprocates.

  In the intake passage 34, an air cleaner 60, an intercooler 62, and a throttle valve 64 are provided in this order from the upstream side. The air cleaner 60 removes foreign matters mixed in the air sucked from the outside air. The intercooler 62 cools the air compressed by the compressor 84 of the supercharger 80 described later. The throttle valve 64 is driven to open and close by an actuator 66 according to the opening of an accelerator (not shown), and adjusts the amount of air sent to the combustion chamber 22.

  A three-way catalyst (Three-way catalyst) 68 and a GPF (Gasoline Particulate Filter) 70 are provided in the exhaust passage 46. The three-way catalyst 68 includes, for example, platinum (Pt), palladium (Pd), and rhodium (Rh). The three-way catalyst 68 removes hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx) in the exhaust gas discharged from the combustion chamber 22.

  The GPF (exhaust gas purification unit) 70 is provided on the downstream side of the three-way catalyst 68 in the exhaust passage 46. The GPF 70 captures (collects) particulate matter (soot) in the exhaust gas exhausted from the combustion chamber 22. The GPF 70 is, for example, a wall flow type filter. The GPF 70 can remove particulate matter from the exhaust gas by depositing particulate matter inside. In the present embodiment, the GPF 70 includes a capturing function for capturing particulate matter and a catalytic function (for example, a three-way catalyst for removing hydrocarbons, carbon monoxide, and nitrogen oxides, similar to the three-way catalyst 68). . The GPF 70 can regenerate the capture function by burning (oxidizing) removing the captured particulate matter.

Specifically, the particulate matter (carbon C) deposited on the GPF 70 is removed from the GPF 70 by advancing a reaction (oxidation reaction of the particulate matter) represented by the following formula (1), and the GPF 70 is regenerated.
C + O ₂ → CO ₂ Formula (1)

  The engine 102 is provided with a supercharger 80. The supercharger 80 includes a turbine 82, a compressor 84, and a turbine shaft 86 that connects the turbine 82 and the compressor 84 so as to be integrally rotatable. The turbine 82 is provided on the upstream side of the three-way catalyst 68 in the exhaust passage 46 and is rotated by the exhaust gas discharged from the combustion chamber 22. The compressor 84 is provided between the air cleaner 60 and the intercooler 62 in the intake flow path 34, rotates with the rotation of the turbine 82, and intake air from which impurities such as dust and dust are removed by the air cleaner 60. Is compressed and supplied downstream.

  Further, the engine 102 is provided with an exhaust gas purification / regeneration device 200 for regenerating the capture function of the GPF 70. The exhaust gas purification / regeneration apparatus 200 includes an air bypass flow path 202, an air bypass valve 204, an on-off valve 205, a branch flow path 206, a branch valve 208, and a branch valve control unit 124 described later.

  The air bypass flow path 202 bypasses the compressor 84, and an intake flow path (hereinafter referred to as upstream intake flow path) 34a on the upstream side of the compressor 84 and an intake flow path (hereinafter referred to as downstream side) of the compressor 84. 34b) (referred to as an intake passage). The air bypass flow path 202 and the upstream side intake flow path 34 a are connected between the air cleaner 60 and the compressor 84. Further, the air bypass passage 202 and the downstream side intake passage 34 b are connected between the compressor 84 and the intercooler 62.

  An air bypass valve 204 is interposed in the air bypass channel 202. The air bypass valve 204 is a diaphragm valve, and opens and closes the air bypass passage 202. The air bypass valve 204 is opened when the pressure of the compressed air flowing from the downstream intake passage 34b into the air bypass passage 202 becomes larger than the pressure in the intake manifold 32. The air bypass valve 204 is closed when the pressure of the compressed air flowing from the downstream intake passage 34b into the air bypass passage 202 becomes smaller than the pressure in the intake manifold 32. For example, the air bypass valve 204 is opened when the pressure in the intake manifold 32 becomes negative, such as when the driver releases the accelerator, and prevents the pressure in the downstream intake passage 34b from becoming excessive. To do.

  An open / close valve 205 is interposed in the air bypass flow path 202. The on-off valve 205 is disposed on the downstream side of the air bypass valve 204 (on the upstream intake flow path 34a side with respect to the air bypass valve 204). The opening / closing valve 205 is configured to be able to open and close the air bypass channel 202. The on-off valve 205 is controlled to be in an open state or a closed state based on a signal transmitted from the ECU 104 (branch valve control unit) 124.

  The branch channel 206 communicates the air bypass channel 202 and the exhaust channel 46. The branch flow path 206 and the air bypass flow path 202 are connected between the open / close valve 205 and the air bypass valve 204. In other words, the branch flow path 206 and the air bypass flow path 202 are connected between a connection portion (merging portion) between the air bypass flow path 202 and the upstream side intake flow path 34 a and the air bypass valve 204. The branch flow path 206 and the exhaust flow path 46 are connected between the three-way catalyst 68 and the GPF 70.

  A branch valve 208 is interposed in the branch channel 206. The branch valve 208 is configured to be able to open and close the branch flow path 206. The opening degree of the branch valve 208 is controlled based on a signal transmitted from the ECU 104 (branch valve control unit 124).

  Further, the engine system 100 is provided with an accelerator opening sensor 90, a crank angle sensor 92, an intake air amount sensor 94, a differential pressure sensor 96, and a temperature sensor 98. The accelerator opening sensor 90 detects the amount of depression of the accelerator pedal. The crank angle sensor 92 is provided in the vicinity of the crankshaft 26 and outputs a pulse signal every time the crankshaft 26 rotates by a predetermined angle. The intake air amount sensor 94 is provided between the air cleaner 60 and the throttle valve 64 in the intake passage 34 and detects the amount of intake air flowing into the engine 102. The differential pressure sensor 96 detects a pressure difference between the upstream side and the downstream side of the GPF 70 in the exhaust passage 46. The temperature sensor 98 detects the temperature of the GPF 70.

  Each of these sensors 90 to 98 is connected to the ECU 104 and outputs a signal indicating the detected value to the ECU 104.

  The ECU 104 acquires signals output from the sensors 90 to 98 and controls the engine 102. When the ECU 104 controls the engine 102, the signal acquisition unit 110, the target value derivation unit 112, the air amount determination unit 114, the injection amount determination unit 116, the throttle opening determination unit 118, the ignition timing determination unit 120, and the drive control unit 122. It functions as the branch valve control unit 124.

  The signal acquisition unit 110 acquires signals indicating values detected by the sensors 90 to 98. The target value deriving unit 112 derives the current engine speed based on the signal indicating the crank angle acquired from the crank angle sensor 92. Further, the target value deriving unit 112 refers to a pre-stored map based on the derived engine speed and a signal indicating the accelerator opening acquired from the accelerator opening sensor 90, and the target torque and the target engine speed. Is derived.

  The air amount determination unit 114 determines a target air amount to be supplied to each cylinder 16 based on the target engine speed and target torque derived by the target value deriving unit 112. The throttle opening degree determination unit 118 derives the total target air amount of each cylinder 16 determined by the air amount determination unit 114, and determines the target throttle opening degree for intake of the total amount of air from the outside.

  The injection amount determination unit 116 determines a target injection amount of fuel to be supplied to each cylinder 16 based on the target air amount of each cylinder 16 determined by the air amount determination unit 114. Further, the injection amount determination unit 116 is based on a signal indicating the crank angle detected by the crank angle sensor 92 in order to inject fuel of the determined target injection amount from the injector 56 in the intake stroke or compression stroke of the engine 102. The target injection timing and target injection period of each injector 56 are determined.

  Based on the target engine speed derived by the target value deriving unit 112 and the signal indicating the crank angle detected by the crank angle sensor 92, the ignition timing determining unit 120 is a target of the spark plug 58 in each cylinder 16. Determine the ignition timing.

  The drive control unit 122 drives the actuator 66 so that the throttle valve 64 is opened at the target throttle opening determined by the throttle opening determination unit 118. In addition, the drive control unit 122 drives the injector 56 at the target injection timing and the target injection period determined by the injection amount determination unit 116, thereby causing the injector 56 to inject the fuel of the target injection amount. In addition, the drive control unit 122 ignites the spark plug 58 at the target ignition timing determined by the ignition timing determination unit 120.

  The branch valve control unit 124 controls the opening degree of the branch valve 208 of the exhaust gas purification / regeneration device 200. The branch valve control unit 124 controls the branch valve 208 to be closed as a basic state. The branch valve control unit 124 controls the branch valve 208 from the closed state to the open state when executing a regeneration process of the GPF 70 described later.

  The branch valve control unit 124 controls the open / close valve 205 to be in an open state or a closed state. The branch valve control unit 124 controls the open / close state of the open / close valve 205 according to the open / close state of the branch valve 208. Specifically, the branch valve control unit 124 controls the open / close valve 205 to a closed state while controlling the branch valve 208 to an open state. Further, the branch valve control unit 124 controls the open / close valve 205 to the open state while the branch valve 208 is controlled to the closed state. Details of the branch valve control unit 124 will be described later.

  The engine 102 of this embodiment is a gasoline engine, and the injection amount determination unit 116 determines an air-fuel ratio according to the engine load. The injection amount determination unit 116 basically determines the target injection amount of fuel so that the stoichiometric air-fuel ratio (stoichiometric) is obtained. Further, the injection amount determination unit 116 determines the target injection amount of fuel so that the output air-fuel ratio (rich) is obtained when power such as starting or acceleration is required (high load). In addition, the injection amount determination unit 116 determines the target injection amount of fuel so as to achieve an economic air-fuel ratio (lean) in order to suppress fuel consumption at low loads.

  Here, in the operation at the theoretical air-fuel ratio or the output air-fuel ratio, the oxygen contained in the exhaust gas has a low concentration, so that the regeneration process of the GPF 70 is not promoted. If the regeneration process is not promoted, particulate matter is deposited on the GPF 70, causing the GPF 70 to be clogged, resulting in a large pressure loss. If it does so, there exists a problem that a fuel consumption will deteriorate.

  Therefore, the engine 102 of the present embodiment includes the exhaust gas purification / regeneration device 200 in order to promote the regeneration process of the GPF 70 during operation at the theoretical air fuel ratio or the output air fuel ratio. The exhaust gas purification / regeneration device 200 (branch valve control unit 124) regenerates the GPF 70 by increasing the oxygen concentration in the exhaust gas by supplying air to the GPF 70 when a predetermined start condition described below is satisfied. Execute the process.

  The branch valve control unit 124 first regenerates the GPF 70 based on the temperature of the GPF 70 and the difference between the pressure upstream of the GPF 70 and the pressure downstream of the GPF 70 in the exhaust passage 46 (hereinafter simply referred to as a pressure difference). It is determined whether or not the start condition is satisfied. Specifically, the branch valve control unit 124 determines whether the temperature of the GPF 70 is lower than a predetermined temperature. The branch valve control unit 124 determines whether the pressure difference between the upstream side and the downstream side of the GPF 70 is equal to or greater than a predetermined pressure. Then, the branch valve controller 124 satisfies the start condition for the regeneration process of the GPF 70 when the temperature of the GPF 70 is lower than the predetermined temperature and the pressure difference between the upstream side and the downstream side of the GPF 70 is equal to or higher than the predetermined pressure. And the GPF 70 reproduction process is executed (started).

  Here, the predetermined temperature is a temperature at which the GPF 70 can be prevented from being damaged due to a temperature rise during the regeneration process of the GPF 70. During the regeneration process of the GPF 70, air is supplied to the GPF 70. When air is supplied to the GPF 70, the temperature of the GPF 70 rises due to the reaction (oxidation reaction of the particulate matter) shown in the above formula (1). When the temperature of the GPF 70 rises above a predetermined temperature, the GPF 70 may be damaged. Therefore, the branch valve control unit 124 determines whether or not the temperature of the GPF 70 is lower than the predetermined temperature, and executes the regeneration process of the GPF 70 when the temperature of the GPF 70 is lower than the predetermined temperature.

  The predetermined pressure is a pressure at which the amount of particulate matter trapped by the GPF 70 can be regarded as being a predetermined amount or more. Here, when the accumulation amount of the particulate matter captured by the GPF 70 is less than a predetermined amount, the capture rate at which the GPF 70 captures the particulate matter is decreased, and the amount of the particulate matter discharged from the GPF 70 is increased. . Therefore, the branch valve control unit 124 determines whether or not the pressure difference between the upstream side and the downstream side of the GPF 70 is equal to or greater than a predetermined pressure, and the pressure difference of the GPF 70 is equal to or greater than the predetermined pressure (that is, the accumulation amount is equal to or greater than the predetermined amount). In some cases, the reproduction process of the GPF 70 is executed.

  Next, the branch valve control unit 124 executes (starts) the regeneration process of the GPF 70 only when operating at the theoretical air-fuel ratio or the output air-fuel ratio when the start condition of the regeneration process of the GPF 70 is satisfied. Specifically, when the temperature of the GPF 70 is lower than the predetermined temperature, the pressure difference of the GPF 70 is equal to or higher than the predetermined pressure, and the branch valve control unit 124 is operating at the theoretical air fuel ratio or the output air fuel ratio, The reproduction process of the GPF 70 is executed. By executing the regeneration process of the GPF 70 during operation at the theoretical air fuel ratio or the output air fuel ratio, the oxygen concentration in the exhaust gas can be increased, and the regeneration process of the GPF 70 can be performed effectively.

  On the other hand, the branch valve control unit 124 does not execute the regeneration process of the GPF 70 when it is operating at the economic air-fuel ratio even if the start condition of the regeneration process of the GPF 70 is satisfied. That is, the branch valve control unit 124 always controls the branch valve 208 to be closed when the operation is being performed at the economic air-fuel ratio even if the start condition for the regeneration process of the GPF 70 is satisfied, and the opening / closing valve 205 is controlled to be closed. Control to open state. This is because when operating at an economic air-fuel ratio, oxygen contained in the exhaust gas has a higher concentration than the stoichiometric air-fuel ratio or the output air-fuel ratio, so the branch valve 208 is controlled to be opened and air is supplied to the GPF 70. However, the GPF 70 regeneration process cannot be effectively performed.

  The branch valve control unit 124 satisfies the conditions for starting the regeneration process of the GPF 70 and is operating at the stoichiometric air fuel ratio or the output air fuel ratio. Based on the driving state of the air bypass valve 204, the branch valve control unit 124 Control the opening. The branch valve control unit 124 controls the driving of the branch valve 208 in conjunction with the air bypass valve 204. For example, the branch valve control unit 124 branches when the air bypass valve 204 is opened and the compressed air flowing through the downstream intake passage 34b returns to the upstream intake passage 34a via the air bypass passage 202. The valve 208 is controlled to be opened. At this time, the branch valve control unit 124 controls the open / close valve 205 to be closed. As a result, the compressed air flowing through the air bypass flow path 202 is supplied to the exhaust flow path 46 (the exhaust flow path 46 between the three-way catalyst 68 and the GPF 70) via the branch flow path 206.

  Here, the pressure in the air bypass passage 202 when the air bypass valve 204 is opened is higher than the pressure in the exhaust passage 46 between the three-way catalyst 68 and the GPF 70. . Therefore, the compressed air flowing through the air bypass channel 202 can flow into the exhaust channel 46 between the three-way catalyst 68 and the GPF 70 via the branch channel 206. The compressed air that has flowed into the exhaust passage 46 between the three-way catalyst 68 and the GPF 70 is supplied to the GPF 70 that is disposed downstream of the three-way catalyst 68. The compressed air (oxygen) supplied to the GPF 70 burns (oxidizes) the particulate matter trapped in the GPF 70 and removes the particulate matter from the GPF 70. By removing the particulate matter from the GPF 70, the GPF 70 can regenerate the capturing function for capturing the particulate matter.

  Further, the branch valve control unit 124 controls the branch valve 208 to be closed when the air bypass valve 204 is closed. At this time, the branch valve control unit 124 controls the open / close valve 205 to be in an open state. As a result, it is possible to prevent air from flowing (backflowing) from the exhaust passage 46 between the three-way catalyst 68 and the GPF 70 into the air bypass passage 202.

  Note that the engine 102 of the present embodiment includes a pressure sensor (not shown) that detects the pressure of compressed air flowing into the air bypass passage 202 from the downstream intake passage 34b and the pressure in the intake manifold 32. The branch valve controller 124 determines (estimates) the driving state (open state or closed state) of the air bypass valve 204 based on a signal output from a sensor (not shown). Accordingly, the branch valve control unit 124 can control the opening degree of the branch valve 208 based on the driving state of the air bypass valve 204. Further, the branch valve control unit 124 may control the opening degree of the branch valve 208 based on a signal (intake air amount) output from the intake air amount sensor 94. Thereby, the amount of air supplied to the GPF 70 via the branch flow path 206 can be optimally controlled.

  According to the present embodiment, when the air bypass valve 204 is opened, air (oxygen) flowing through the air bypass flow path 202 is supplied to the GPF 70 via the branch flow path 206. Therefore, when supplying air to the GPF 70 via the branch flow path 206, it is necessary to separately provide a configuration in which the pressure on the inflow side (intake side) of the branch flow path 206 is higher than the pressure on the discharge side (exhaust side). Disappear. Therefore, the exhaust gas purification / regeneration apparatus 200 of the present embodiment can execute the regeneration process of the GPF 70 with a simple configuration. Here, when air is supplied from the intake flow path 34 to the exhaust flow path 46 via the branch flow path 206, it is necessary to make the intake pressure in the intake flow path 34 higher than the exhaust pressure in the exhaust flow path 46, which is wasteful. The compressor 84 must be driven to rotate. On the other hand, the branch flow path 206 of the present embodiment supplies the GPF 70 with compressed air (excess compressed air) that recirculates from the downstream intake flow path 34b to the upstream intake flow path 34a via the air bypass flow path 202. Therefore, the compressor 84 need not be rotationally driven.

  FIG. 2 is a flowchart of the regeneration process of the GPF 70 by the branch valve control unit 124.

  First, the branch valve control unit 124 derives the current temperature of the GPF 70 based on a signal output from the temperature sensor 98. Further, the branch valve control unit 124 derives the current pressure difference between the upstream side and the downstream side of the GPF 70 based on the signal output from the differential pressure sensor 96. Then, the branch valve control unit 124 determines whether the temperature of the GPF 70 is lower than a predetermined temperature and whether the pressure difference between the upstream side and the downstream side of the GPF 70 is equal to or higher than the predetermined pressure. (Step S102). If the temperature of the GPF 70 is lower than the predetermined temperature and the pressure difference between the upstream side and the downstream side of the GPF 70 is equal to or higher than the predetermined pressure (YES in step S102), the branch valve control unit 124 proceeds to step S104. On the other hand, when the temperature of GPF 70 is equal to or higher than the predetermined temperature or the pressure difference between the upstream side and the downstream side of GPF 70 is less than the predetermined pressure (NO in step S102), branch valve control unit 124 ends the regeneration process of GPF 70. (The GPF 70 is not played back). When the regeneration process of the GPF 70 is not performed, the air bypass valve 204 is opened / closed according to the pressure in the intake manifold 32 and the like to prevent a surge from being generated in the intake passage 34. When the air bypass valve 204 is opened to prevent the occurrence of a surge, the opening / closing valve 205 is also opened.

  If YES in step S102, the branch valve control unit 124 determines whether or not the operation at the stoichiometric air fuel ratio or the output air fuel ratio is being performed (step S104). If the operation at the theoretical air-fuel ratio or the output air-fuel ratio is being performed (YES in step S104), the branch valve control unit 124 proceeds to step S106. On the other hand, when the operation at the stoichiometric air-fuel ratio or the output air-fuel ratio is not performed, that is, when the operation at the economic air-fuel ratio is performed (NO in step S104), the branch valve control unit 124 returns to step S102. The determination in step S102 is performed again.

  If YES in step S104, the branch valve control unit 124 determines whether or not the air bypass valve 204 is open (step S106). If branch valve control unit 124 determines that air bypass valve 204 is open (YES in step S106), it proceeds to step S108. On the other hand, when branch valve control unit 124 determines that air bypass valve 204 is not in the open state, that is, in the closed state (NO in step S106), the process proceeds to step S110.

  If YES in step S106, the branch valve controller 124 controls the branch valve 208 to be open (step S108). At this time, the branch valve control unit 124 controls the open / close valve 205 to be closed. The branch valve control unit 124 controls whether or not the air bypass valve 204 has changed from the open state to the closed state after controlling the branch valve 208 to the open state (that is, whether or not the air bypass valve 204 is in the closed state). Determination is made (step S112).

  If the branch valve control unit 124 determines that the air bypass valve 204 is not closed (NO in step S112), the branch valve control unit 124 repeatedly performs the determination in step S112 until the air bypass valve 204 is closed. That is, the branch valve control unit 124 controls the branch valve 208 to the open state while the air bypass valve 204 is maintained in the open state. On the other hand, when the branch valve control unit 124 determines that the air bypass valve 204 is closed (YES in step S112), the branch valve control unit 124 controls the branch valve 208 to be closed (step S114). At this time, the branch valve control unit 124 controls the open / close valve 205 to be in an open state. After controlling the branch valve 208 to the closed state, the branch valve control unit 124 returns to Step S102 and performs the determination in Step S102 again.

  On the other hand, if NO in step S106, the branch valve control unit 124 controls the branch valve 208 to be closed (step S110). At this time, the branch valve control unit 124 controls the open / close valve 205 to be in an open state. After controlling the branch valve 208 to the closed state, the branch valve control unit 124 returns to Step S102 and performs the determination in Step S102 again.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  In the above embodiment, the air bypass valve 204 opens and closes the air bypass passage 202 according to the pressure of the compressed air flowing into the air bypass passage 202 from the downstream side intake passage 34b and the pressure in the intake manifold 32. An example to do. However, the present invention is not limited to this, and the air bypass valve 204 may be an electronic control valve controlled by the ECU 104 (branch valve control unit 124). In this case, the ECU 104 (branch valve control unit 124) can control the opening and closing of the branch valve 208 in accordance with the opening and closing of the electronic control valve.

  Further, instead of the on-off valve 205 and the branch valve 208, a three-way valve may be provided at a connection portion (merging portion) between the branch flow path 206 and the air bypass flow path 202. By providing a three-way valve at the connection between the branch flow path 206 and the air bypass flow path 202, compressed air flowing through the air bypass flow path 202 can be supplied to the GPF 70 during the regeneration process of the GPF 70. Specifically, the branch valve control unit 124 shuts off the communication between the air bypass flow path 202 and the upstream side intake flow path 34a, and controls the three-way valve so as to connect the air bypass flow path 202 and the branch flow path 206. Control.

  Further, the branch valve control unit 124 controls the three-way valve so that the communication between the air bypass flow path 202 and the branch flow path 206 is blocked and the air bypass flow path 202 and the upstream intake flow path 34a are connected. be able to. As a result, the compressed air flowing through the air bypass passage 202 is returned to the upstream intake passage 34a.

  Further, the branch valve control unit 124 may increase the work amount of the turbine 82 during the regeneration process of the GPF 70. By increasing the work amount of the turbine 82, the work amount of the compressor 84 also increases, so that the amount of compressed air flowing through the air bypass passage 202 can be increased. As a result, the amount of air (oxygen) supplied to the GPF 70 can be increased, and the regeneration process of the GPF 70 can be performed more effectively.

  Further, in the above embodiment, an example in which the branch valve control unit 124 executes the regeneration process of the GPF 70 when the air-fuel ratio determined according to the engine load state is the theoretical air-fuel ratio or the output air-fuel ratio. did. However, the present invention is not limited to this, and the branch valve control unit 124 determines that the temperature of the GPF 70 is lower than the predetermined temperature and the pressure difference between the upstream side and the downstream side of the GPF 70 is equal to or higher than the predetermined pressure regardless of the air-fuel ratio. In addition, the regeneration process of the GPF 70 may be executed.

  Further, in the above-described embodiment, the branch valve control unit 124 has been described as an example of controlling the opening degree of the branch valve 208 in conjunction with the driving state (open state or closed state) of the air bypass valve 204. However, the present invention is not limited to this, and the branch valve control unit 124 may control the opening degree of the branch valve 208 without interlocking with the driving state of the air bypass valve 204. For example, the branch valve control unit 124 controls the branch valve 208 to be opened when the air bypass valve 204 is opened. Then, the branch valve control unit 124 controls the branch valve 208 to be closed after a predetermined time from when the air bypass valve 204 is opened, even if the air bypass valve 204 is open. Also good.

  The present invention can be used for an exhaust gas purification / regeneration apparatus.

34 Intake channel 46 Exhaust channel 70 GPF (Exhaust gas purification unit)
84 Compressor 124 Branch valve control unit 200 Exhaust gas purification / regeneration device 202 Air bypass passage 204 Air bypass valve 206 Branch passage 208 Branch valve

Claims (4)

An air bypass passage for communicating the upstream side and the downstream side of the compressor provided in the intake passage;
An air bypass valve for opening and closing the air bypass flow path;
A branch channel that branches from the air bypass channel and communicates with an exhaust channel having an exhaust gas purification unit;
A branch valve for opening and closing the branch flow path;
Based on the driving state of the air bypass valve, a control unit for controlling the opening of the branch valve;
Exhaust gas purification / regeneration device with The controller is
When the air bypass valve is open, the branch valve is controlled to open,
The exhaust gas purification / regeneration apparatus according to claim 1, wherein the branch valve is controlled to be closed when the air bypass valve is closed. The exhaust gas purification / regeneration apparatus according to claim 1 or 2, wherein the control unit controls the opening degree of the branch valve according to an air-fuel ratio determined according to an engine load. The controller is
When the air-fuel ratio is the stoichiometric air-fuel ratio or rich and the air bypass valve is open, the branch valve is controlled to be open,
The exhaust gas purification / regeneration apparatus according to claim 3, wherein the branch valve is controlled to be closed when the air-fuel ratio is lean or the air bypass valve is closed.

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