JP6696325B2 - Vehicle exhaust purification device - Google Patents

Description

  The present invention relates to an exhaust emission control device mounted on a vehicle.

  As a technique for collecting and removing particulate matter (Particulate Matter) contained in the exhaust gas of internal combustion engines installed in automobiles and other vehicles, provide a particulate filter for collecting particulates in the exhaust pipe. It has been known.

  In the particulate filter, the collected particulates are burned and removed by a filter regeneration process, but this filter process increases fuel consumption. Conventionally, there is known one that uses evaporative fuel in order to suppress an increase in fuel consumption (see, for example, Patent Document 1).

  The evaporated fuel processing device described in Patent Document 1 supplies evaporated fuel collected in activated carbon of a canister to a catalytic converter by a mechanical supercharger driven by an internal combustion engine, and then supplied to the catalytic converter. The fuel component is oxidized by the oxidation catalyst.

Japanese Utility Model Publication No. 2-115850

  In such a conventional evaporated fuel processing apparatus, a mechanical supercharger driven by an internal combustion engine supplies evaporated fuel to the catalytic converter, so that a mechanical supercharger is required. As a result, the manufacturing cost of the device increases and the fuel efficiency of the internal combustion engine deteriorates.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an exhaust emission control device for a vehicle that can efficiently remove particulates from a particulate filter with a simple configuration. To do.

The present invention connects a canister for collecting evaporated fuel generated in a fuel tank, the canister and an internal combustion engine, and an evaporated fuel passage for discharging evaporated fuel collected in the canister to the internal combustion engine, An exhaust passage through which exhaust gas is discharged from an internal combustion engine, a catalytic converter provided in the exhaust passage for purifying exhaust gas discharged from the internal combustion engine, and an exhaust passage provided in the exhaust passage and passing through the catalytic converter A particulate filter that collects included particulates and an exhaust turbine provided in the exhaust passage so as to be located between the internal combustion engine and the catalytic converter are provided, and intake air is exhausted using exhaust pressure. An exhaust gas purification apparatus for a vehicle, comprising: a turbocharger for supercharging, wherein the exhaust gas is provided between one end of the exhaust gas turbine upstream of the exhaust turbine and connected to the exhaust pipe; e Bei the bypass passage and a second end portion connected to the passage, wherein when there is a fuel cut request to the internal combustion engine, and supplying the vaporized fuel and the intake air into the particulate filter through the bypass passage The particulate filter is regenerated.

  As described above, according to the present invention, it is possible to efficiently remove particulates from the particulate filter with a simple configuration.

FIG. 1 is a schematic configuration diagram of an internal combustion engine including an exhaust emission control device for a vehicle according to an embodiment of the present invention. FIG. 2 is a flowchart of GPF activation purge control in the vehicle exhaust emission control device according to the embodiment of the present invention.

Embodiments of an exhaust emission control system for a vehicle according to the present invention will be described below with reference to the drawings.
1 and 2 are views showing an exhaust emission control system for a vehicle according to an embodiment of the present invention.
First, the configuration will be described.
In FIG. 1, a vehicle such as an automobile is equipped with a gasoline engine (hereinafter, simply referred to as an engine) 1 as an internal combustion engine. The engine 1 includes a plurality of cylinders 2, and a piston (not shown) is housed in each cylinder.

  Each engine 1 is provided with a fuel injection valve 3, and the fuel injection valve 3 is installed in each intake port (not shown) communicating with each of the cylinders 2. The fuel injection valve 3 is connected to the delivery pipe 4.

The delivery pipe 4 is connected to the fuel tank 5 via the fuel pipe 4A, and supplies the fuel (gasoline) supplied from the fuel tank 5 to each fuel injection valve 3.
An intake device 6 is attached to the engine 1. The intake device 6 includes an intake duct 7, an air cleaner 8, an intake pipe 9, and an intake manifold 10.

  The intake duct 7 has an opening for taking in air (outside air), and the air taken in through the opening is introduced into the air cleaner 8. The air cleaner 8 has an air filter 8B built in an air cleaner body 8A, and the air filter 8B removes and purifies foreign matter from the air taken in from the intake duct 7.

The intake pipe 9 introduces the purified air into the intake manifold 10. The intake manifold 10 communicates with each cylinder 2 and distributes and introduces intake air into each cylinder 2.
The engine 1 performs combustion by igniting the air drawn into each cylinder 2 and the fuel injected from the fuel injection valve 3 with an ignition plug (not shown).

  A throttle valve 9A is attached to the intake pipe 9. The throttle valve 9A adjusts the amount of air taken into the cylinder 2 by adjusting the opening degree of the intake pipe 9 according to the operation amount of an accelerator pedal (not shown).

  An exhaust device 11 is attached to the engine 1. The exhaust device 11 includes an exhaust manifold 12, a catalytic converter 13, a gasoline particulate filter (hereinafter, simply referred to as GPF) 14, and an exhaust pipe 15.

  The exhaust manifold 12 is connected to the engine 1. Exhaust gas is discharged from each cylinder 2 to the exhaust manifold 12, and the exhaust manifold 12 joins the exhaust gas discharged from each cylinder 2.

  The exhaust pipe 15 is connected to the downstream end of the exhaust manifold 12. The exhaust pipe 15 is provided with a catalytic converter 13, and the exhaust gas discharged to the exhaust manifold 12 is discharged to the catalytic converter 13.

The catalytic converter 13 contains a catalyst 13B in a casing 13A, and the catalyst 13B reacts unburned components such as HC (hydrocarbon) and CO (carbon monoxide) contained in exhaust gas with O ₂ (oxygen). Then, it is purified by being oxidized into CO, CO ₂ (carbon dioxide), H ₂ O (water) and the like.

  The exhaust pipe 15 is provided with a GPF 14, and the GPF 14 is built in the casing 14A. The GPF 14 is formed in a honeycomb shape, and collects particulate matter, which is particulate matter.

  The exhaust pipe 15 includes a muffler (not shown) downstream of the GPF 14. The exhaust pipe 15 silences the exhaust gas discharged from the GPF 14 by the muffler, and discharges it from the downstream opening end to the outside (atmosphere). The exhaust pipe 15 of the present embodiment constitutes the exhaust passage of the present invention.

The engine 1 is provided with a turbocharger 41. It has a compressor wheel 41A and a turbine wheel 41B.
The compressor wheel 41A is provided in the intake pipe 9 on the downstream side of the air cleaner 8. The turbine wheel 41B is provided in the exhaust pipe 15 so as to be located between the engine 1 and the catalytic converter 13.

  The turbine wheel 41B is connected to the compressor wheel 41A and rotates integrally with the compressor wheel 41A. The turbine wheel 41B rotates using the exhaust pressure discharged from the engine 1, and the compressor wheel 41A rotates integrally with the turbine wheel 41B to supercharge intake air and introduce it into the engine 1. The turbine wheel 41B of the present embodiment constitutes the exhaust turbine of the present invention.

A canister 16 is attached to the engine 1. The canister 16 includes a canister body 16A and an adsorbent 16B such as activated carbon contained in the canister body 16A.
The canister body 16A is connected to the fuel tank 5 by a vapor pipe 17, and the fuel vapor generated inside the fuel tank 5 is introduced into the canister body 16A through the vapor pipe 17. The adsorbent 16B adsorbs the evaporated fuel introduced into the canister body 16A.

  An air introducing pipe 18 is attached to the canister body 16A, and the air introducing pipe 18 introduces air into the canister body 16A. The canister body 16A is connected to the intake manifold 10 by a purge pipe 19.

  A purge valve 20 is attached to the purge pipe 19, and the opening of the purge valve 20 is changed by, for example, duty control of the exciting current of the purge valve 20, and the flow rate of the purge gas flowing through the purge pipe 19 is adjusted.

  When the purge valve 20 is opened at an opening degree according to the duty ratio, the evaporated fuel desorbed from the adsorbent 16B due to the intake negative pressure inside the intake manifold 10 is introduced into the canister body 16A from the air introduction pipe 18. Together with this, it is sucked into the intake manifold 10 as purge gas.

  The purge gas sucked into the intake manifold 10 is burned in the cylinder 2 and discharged from the exhaust device 11 to the outside. The purge pipe 19 may be attached to the intake pipe 9 as long as it is attached downstream of the throttle valve 9A in the air flow direction. Further, the mounting position of the purge pipe 19 with respect to the intake manifold 10 is not particularly limited.

  The engine 1 is provided with a bypass pipe 21. The bypass pipe 21 has one end 21a connected to the exhaust pipe 15 on the upstream side of the turbine wheel 41B, and the other end 21b connected to the exhaust pipe 15 between the catalytic converter 13 and the GPF 14.

  That is, the bypass pipe 21 of the present embodiment is branched from the exhaust pipe 15 on the upstream side of the turbine wheel 41B and bypasses the turbine wheel 41B and the catalytic converter 13 to the exhaust pipe 15 between the catalytic converter 13 and the GPF 14. It is connected. Here, the terms “upstream” and “downstream” refer to upstream and downstream with respect to the flow direction of exhaust gas.

  A wastegate valve 22 is attached to the bypass pipe 21, and the opening of the wastegate valve 22 is changed by, for example, duty control of an exciting current of the wastegate valve 22 to adjust the flow rate of exhaust gas flowing through the bypass pipe 21. To do.

  When the wastegate valve 22 is opened at an opening degree corresponding to the duty ratio and the valve 24 described later is opened, exhaust gas bypasses the turbine wheel 41B and the catalytic converter 13 and is introduced into the GPF 14 through the bypass pipe 21. The exhaust gas discharged from the engine 1 to the exhaust manifold 12 includes exhaust gas in which a mixture of fuel and air is burned and air at the time of fuel cut.

  The bypass pipe 21 and the exhaust pipe 15 are connected by a connection pipe 23. One end 23a of the connecting pipe 23 is connected to the downstream side of the wastegate valve 22 of the bypass pipe 21, and the other end 23b of the connecting pipe 23 is downstream of the turbine wheel 41B and upstream of the catalytic converter 13. It is connected to the exhaust pipe 15 on the side.

  The bypass pipe 21 is provided with a valve 24 that adjusts the flow rate of the exhaust gas flowing through the connection pipe 23, and the valve 24 is installed on the downstream side of the one end 23 a of the connection pipe 23. The opening of the valve 24 changes, for example, when its exciting current is duty-controlled, and the flow rate of the exhaust gas flowing through the connecting pipe 23 is adjusted. When the valve 24 is opened at an opening degree according to the duty ratio, the exhaust gas flowing through the bypass pipe 21 can be discharged to the GPF 14 through the connection pipe 23.

  The bypass pipe 21 of the present embodiment constitutes the bypass passage of the present invention, and the purge pipe 19 constitutes the evaporated fuel passage of the present invention. The connection pipe 23 constitutes the connection path of the present invention. The exhaust device 11, the canister 16, the bypass pipe 21, the waste gate valve 22, the connecting pipe 23, and the valve 24 constitute the exhaust purification device 50 of the present invention.

  The purge valve 20, the waste gate valve 22 and the valve 24 are controlled by an ECU (Electronic Control Unit) 31. The ECU 31 is composed of a controller including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., which are not shown.

  Next, the GPF activation purge control will be described based on the flowchart shown in FIG. The GPF activation purge control program of FIG. 2 is stored in the ROM, and the GPF activation purge control program is executed by the CPU.

  In FIG. 2, the ECU 31 determines whether the purge request flag is on (step S1). The purge request flag turns on when the adsorbent 16B of the canister 16 adsorbs a predetermined amount or more of evaporated fuel. For example, it is turned on when a certain period of time has passed since the last purge was performed. Further, the predetermined amount or more means at least an amount capable of reproducing the GPF 14.

  In step S1, if the ECU 31 determines that the purge request flag is not turned on, the process proceeds to step S8, and if it is determined that the purge request flag is turned on, the fuel cut execution flag is set. It is determined whether or not is on (step 2).

  When the ECU 31 determines in step S2 that the fuel cut flag is not on, the process proceeds to step S8. When it is determined in step S2 that the fuel cut flag is on, the ECU 31 determines whether or not the particulates collected in the GPF 14 are equal to or more than a predetermined amount (step S3).

  When the ECU 31 determines in step S3 that the particulate matter collected in the GPF 14 is less than the predetermined amount, the ECU 31 proceeds to step S8 and determines that the particulate matter collected in the GPF 14 is equal to or more than the predetermined amount. If so, the process proceeds to step S4.

  The ECU 31 estimates the collected amount of particulates based on the differential pressure of pressure sensors (not shown) provided upstream and downstream of the GPF 14 or the collected amount calculation data based on the operating state, so that the GPF 14 collects the collected amount of particulates. Detect the amount of particulates that are lost.

  In step S4, the ECU 31 determines whether or not the temperature of the GPF 14 is the proper temperature, and when it is determined that the temperature of the GPF 14 is not the proper temperature, the process proceeds to step S8. If the ECU 31 determines that the temperature of the GPF 14 is appropriate, the ECU 31 opens the purge valve 20 at a predetermined opening (step S5).

  When the purge valve 20 is opened, the evaporated fuel desorbed from the adsorbent 16B due to the negative intake pressure inside the intake manifold 10 is sucked into the intake manifold 10 as purge gas together with the air introduced into the canister body 16A from the air introduction pipe 18. To be done.

  Next, the ECU 31 opens the wastegate valve 22 at a predetermined opening (step S6), opens the valve 24 at an opening based on the operating state of the engine 1 (step S7), and ends this processing. .. As a result, the mixed gas in which the purge gas discharged from the engine 1 to the exhaust pipe 15 and the air are mixed is discharged to the bypass pipe 21.

  The mixed gas discharged to the bypass pipe 21 bypasses the turbine wheel 41B and the catalytic converter 13 and is introduced into the GPF 14. As a result, the particulates captured by the GPF 14 are burned and removed, so that the filter regeneration processing of the GPF 14 is performed. As a result, the clogging of the GPF 14 can be eliminated, and the exhaust resistance can be reduced.

  Here, in step S2, the ECU 31 determines whether or not the fuel cut is performed because oxygen is required to promote combustion when burning the particulates collected in the GPF 14. During the fuel cut, the outside air containing no fuel can be directly introduced into the bypass pipe 21, so that the combustion can be promoted by using this air.

  When the mixed gas is introduced into the GPF 14 from the bypass pipe 21, the mixed gas of air and purge gas does not pass through the catalytic converter 13. As a result, the mixed gas can be prevented from being oxidized by the catalytic converter 13, and the filter regeneration process of the GPF 14 can be performed more effectively.

  In step S4, the ECU 31 determines the temperature of the GPF 14 because the GPF 14 may be thermally deteriorated when the GPF 14 is burned when the GPF 14 is too high, and the purge gas may not be burned when the GPF 14 is too low. Therefore, it is necessary to burn the purge gas without thermally deteriorating the GPF 14.

  In step S8, the ECU 31 executes normal control for determining whether or not the flag for opening the purge valve 20 is on. When the ECU 31 determines that the intake pressure is equal to or lower than the atmospheric pressure, that is, the negative pressure, based on the intake pressure of the intake manifold 10, the ECU 31 turns on the flag for opening the purge valve 20, and proceeds to step S9.

  If the ECU 31 determines that the intake pressure is higher than the atmospheric pressure, that is, the positive pressure, based on the intake pressure of the intake manifold 10, the ECU 31 does not turn on the flag for opening the purge valve 20 and proceeds to step S13. Proceed to. In step S13, the ECU 13 closes the purge valve 20 and proceeds to step S10. As a result, the purge gas is not introduced into the intake manifold 10.

  In step S9, the ECU 31 opens the purge valve 20. As a result, the purge gas is introduced from the canister 16 into the cylinder 2 through the intake manifold 10 and burned in the cylinder 2.

  In step S10, the ECU 31 executes normal control for determining whether the flag for opening the wastegate valve 22 is on. In step S10, the ECU 31 estimates the rotation speed of the turbine wheel 41B from the rotation speed of the engine 1 and the pressure of the intake pipe 9 in order to determine whether the turbine wheel 41B is in the over-rotation state. It is determined whether the wheel 41B is in the over-rotation state.

  Alternatively, a sensor for detecting the rotation speed of the turbine wheel 41B is provided, and the ECU 31 detects the rotation speed of the turbine wheel 41B based on the detection information of the sensor and determines whether the turbine wheel 41B is in the over-rotation state. .. The means for determining whether the turbine wheel 41B is in the over-rotation state is not limited to these.

  When the ECU 31 determines in step S10 that the flag for opening the wastegate valve 22 is not on, the turbine wheel 41B is not over-rotated, and thus the process proceeds to step S14. On the other hand, when it is determined that the flag for opening the wastegate valve 22 is ON, the turbine wheel 41B is over-rotating, so the process proceeds to step S11.

  In step S14, the ECU 31 closes the wastegate valve 22, then proceeds to step S12, closes the valve 24 (step S12), and ends the processing of this time. As a result, the turbine wheel 41B is rotated by the exhaust pressure discharged from the engine 1 to the exhaust pipe 15.

  In step S11, the ECU 13 opens the wastegate valve 22 at an opening degree based on the operating state of the engine 1, then closes the valve 24 (step S12), and ends the processing of this time.

  As a result, a part of the exhaust gas flowing through the turbine wheel 41B is discharged to the bypass pipe 21, and the turbine wheel 41B is prevented from excessive rotation. Therefore, it is possible to obtain a stable supercharging pressure and protect the engine 1 and the turbocharger 41.

  As described above, according to the exhaust emission control device 50 of the present embodiment, the one end 21a connected to the exhaust pipe 15 on the upstream side of the turbine wheel 41B and the exhaust pipe 15 between the catalytic converter 13 and the GPF 14 are connected. And a bypass pipe 21 opened and closed by a waste gate valve 22.

  As a result, the bypass pipe 21 having the waste gate valve 22 is extended from the upstream side of the turbine wheel 41B between the catalytic converter 13 and the GPF 14 to supply the mixed gas of the purge gas and the air to the GPF 14, and the GPF 14 is supplied. Can be burnt to remove particulates. Further, since the particulate matter can be burned and removed from the GPF 14 using the evaporated fuel, it is possible to prevent the fuel economy of the engine 1 from being deteriorated.

  Further, according to the exhaust emission control device 50 of the present embodiment, the one end 23a is connected to the bypass pipe 21, and the other end 23b is on the downstream side of the turbine wheel 41B and on the upstream side of the catalytic converter 13 in the exhaust pipe 15. A connection pipe 23 connected to the is provided.

Further, the connection pipe 23 is provided with a valve 24 that adjusts the amount of exhaust gas flowing through the bypass pipe 21, and the valve 24 is installed on the downstream side of one end 23 a of the connection pipe 23.
As a result, at the time of fuel injection, the exhaust gas can be discharged to the catalytic converter 13 as necessary, and the exhaust gas can be purified by the catalytic converter 13.

  In this embodiment, the particulate filter is applied to the gasoline engine, but the particulate filter may be applied to the diesel engine.

  Although an embodiment of this invention has been disclosed, it will be apparent to those skilled in the art that changes may be made without departing from the scope of this invention. All such modifications and equivalents are intended to be included in the following claims.

1 ... Engine (internal combustion engine), 13 ... Catalytic converter, 14 ... Gasoline particulate filter, 15 ... Exhaust pipe (exhaust passage), 16 ... Canister, 19 ... Purge pipe ( Evaporated fuel passage), 21 ... Bypass pipe (bypass passage), 21a ... One end (one end of bypass passage), 21b ... Another end (other end of bypass passage), 23 ... connection pipe (connection path), 23a ... one end (connection path one end of), 23b ... other end (connection path other end of), 24 ... valve, 4 1 ... turbocharger 4 1 B ... Turbine wheel (exhaust turbine), 50 ... Exhaust gas purification device

Claims (2)

A canister for collecting the evaporated fuel generated in the fuel tank,
An evaporated fuel passage that connects the canister and an internal combustion engine and discharges the evaporated fuel collected in the canister to the internal combustion engine;
An exhaust passage through which exhaust gas is discharged from the internal combustion engine;
A catalytic converter provided in the exhaust passage for purifying exhaust gas discharged from the internal combustion engine;
A particulate filter that is provided in the exhaust passage and collects particulates contained in the exhaust gas that has passed through the catalytic converter;
Exhaust gas purification of a vehicle having an exhaust turbine provided in the exhaust passage so as to be located between the internal combustion engine and the catalytic converter, and including a turbocharger that supercharges intake air by utilizing exhaust pressure A device,
E Bei one end portion connected to the exhaust passage at an upstream side of the exhaust turbine, a bypass passage and a second end portion connected to the exhaust passage between said catalytic converter and the particulate filter,
When there is a fuel cut request to the internal combustion engine, the intake air and the evaporated fuel are supplied to the particulate filter through the bypass passage to regenerate the particulate filter. Purification device. A connection path is provided, one end of which is connected to the bypass passage and the other end of which is connected to the exhaust passage on the downstream side of the exhaust turbine and on the upstream side of the catalytic converter.
The bypass passage is provided with a valve for adjusting the amount of exhaust gas flowing through the bypass passage,
The exhaust emission control device for a vehicle according to claim 1, wherein the valve is installed downstream of one end of the connection path.

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