JP2006194170A - Exhaust gas cleaning device in hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize enhancement of an exhaust gas cleaning efficiency by enhancing reduction efficiency of an NOx catalyst occuluded by preventing flowing out of uncleand NOx and a reducing agent in the exhaust gas cleaning device in a hybrid vehicle. <P>SOLUTION: The exhaust gas cleaning device 50 comprising a first catalyst 51 and a second catalyst 52 reducible by occuluding NOx in the exhaust gas is provided in an exhaust pipe 46 and a fuel addition valve 57 for feeding the fuel as the reducing agent to the respective catalysts 51, 52 is provided. An electric assist turbo-supercharger is driven at EV traveling by MG12 and MG13 that DE 11 is stopped and a predetermined amount of fuel is injected from the fuel addition valve 57 to an exhaust port 33, thereby, the fuel as the reducing agent is fed to the exhaust gas cleaning device 50. At this time, the fuel is reciprocated in the first catalyst 51 and the second catalyst 52 by repeating normal rotation driving and reverse rotation driving of the electric assist turbo-supercharger. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an exhaust emission control device in which an NOx storage reduction catalyst is provided in an exhaust passage of an internal combustion engine in a hybrid vehicle that can travel using an internal combustion engine and an electric motor as power sources.

  An NOx storage reduction catalyst that stores NOx in the exhaust gas when the exhaust air-fuel ratio is lean, releases the NOx stored when the oxygen concentration in the exhaust gas decreases, and reduces it with the added reducing agent. Is already known. As an exhaust purification device having this NOx storage reduction catalyst, there are those described in Patent Documents 1 and 2 below.

  The exhaust purification device described in the following Patent Document 1 is provided with an NOx storage reduction catalyst in the middle of an exhaust pipe through which exhaust gas flows and an injection nozzle for injecting a reducing agent to the NOx storage reduction catalyst, A bypass passage that bypasses the NOx storage reduction catalyst is provided. Therefore, during lean combustion operation, exhaust gas is passed through the NOx storage reduction catalyst to store NOx, and when this storage capacity is reduced, exhaust gas passing through the NOx storage reduction catalyst by flowing exhaust gas through the bypass passage. After limiting the gas flow rate, a reducing agent is injected to reduce and regenerate NOx.

  Further, the exhaust gas purification apparatus for an internal combustion engine described in Patent Document 2 branches the exhaust pipe to provide first and second exhaust passages, and provides an exhaust control valve in each exhaust passage and absorbs NOx downstream thereof. A material is provided and a reducing agent supply port for supplying a reducing agent to the NOx absorbent is provided. Therefore, when the first control valve is opened, the exhaust gas is allowed to flow through the NOx absorbent in the first exhaust passage to absorb NOx. When this absorption capacity is reduced, the first control valve is closed while the second control valve is closed. The control valve is opened so that exhaust gas flows through the NOx absorbent in the second exhaust passage to absorb NOx, and a reducing agent is supplied to the NOx absorbent in the first exhaust passage to reduce and regenerate NOx. ing.

JP 2001-140635 A Japanese Patent Laid-Open No. 7-102947

  In the exhaust purification device of Patent Document 1 described above, when the storage capacity of the NOx storage reduction catalyst is reduced, the flow rate of the exhaust gas passing through the NOx storage reduction catalyst is limited, and then the NOx storage reduction catalyst is reduced. The agent is supplied and regenerated. Further, in the exhaust gas purification apparatus for an internal combustion engine disclosed in Patent Document 2, when the absorption capacity of one NOx absorbent is reduced, the exhaust gas is caused to flow through the other exhaust passage, and the reducing agent is supplied to the NOx absorbent in the one exhaust passage. And playing. For this reason, any exhaust purification device can regenerate the NOx storage reduction catalyst and NOx absorbent without releasing the reducing agent to the outside.

  By the way, the NOx storage reduction catalyst having a reduced storage capacity is supported on the surface of the void when the reducing agent passes through the void of the NOx storage reduction catalyst in an atmosphere having a reduced oxygen concentration. The NOx reduction efficiency is reduced when the contact area between the reducing agent and the surface of the NOx storage reduction catalyst is increased. The exhaust gas purification efficiency is improved. However, when the hybrid vehicle is driven by an electric motor, the flow of exhaust gas to the NOx storage reduction catalyst is stopped. If the reducing agent is added in a state where the flow of exhaust gas to the NOx absorbent is stopped, the reducing agent is not sufficiently diffused in the exhaust passage, and the contact between the NOx storage reduction catalyst and the reducing agent becomes insufficient. Therefore, the stored NOx cannot be efficiently reduced, and as a result, the exhaust gas purification efficiency is lowered.

  An object of the present invention is to provide an exhaust emission control device in a hybrid vehicle that solves such a problem and that improves exhaust gas purification efficiency by improving the reduction efficiency of the stored NOx catalyst. And

  In order to solve the above-described problems and achieve the object, an exhaust emission control device for a hybrid vehicle according to the present invention is provided in an exhaust passage of the internal combustion engine in a hybrid vehicle that can run using an internal combustion engine and an electric motor as power sources. A NOx storage reduction catalyst capable of storing and reducing NOx in the exhaust gas, a reducing agent supply means for supplying a reducing agent to the NOx storage reduction catalyst, and a supply of the reducing agent during vehicle travel by the electric motor And a stirring means for reciprocating the reducing agent supplied by the means in the vicinity of the NOx storage reduction catalyst.

  Therefore, when the reducing agent is supplied from the reducing agent supply means to the storage reduction type NOx catalyst when the traveling by the internal combustion engine is switched to the driving by the electric motor, the reducing agent is supplied to the NOx storage reduction catalyst by the stirring means. In this NOx storage reduction catalyst, the reaction is promoted by stirring the reducing agent inside, and NOx is efficiently reduced, so that unpurified NOx and unused reducing agent are removed. There is almost no outflow from the NOx storage reduction catalyst, and there is no need to provide an auxiliary catalyst downstream of the NOx storage reduction catalyst. As a result, the reduction efficiency of the stored NOx catalyst is improved and the exhaust purification efficiency is improved. Can be improved.

  In the exhaust gas purification apparatus for a hybrid vehicle according to the present invention, the agitation means has an intake passage and an electrically assisted turbocharger provided in the exhaust passage, and repeats forward and reverse rotation of the electrically assisted turbocharger. Thus, the reducing agent is reciprocated in the vicinity of the NOx storage reduction catalyst.

  Therefore, when the traveling by the internal combustion engine is switched to the traveling by the electric motor, the reductant reciprocates internally in this NOx storage reduction catalyst by repeating the forward rotation and reverse rotation of the electric assist turbocharger. Since it is moved and stirred, the reaction with the NOx storage reduction catalyst by the reducing agent is promoted, and the reduction efficiency of the NOx catalyst easily stored by the existing equipment is improved to improve the exhaust purification efficiency. Can do.

  In the exhaust emission control device for a hybrid vehicle of the present invention, the agitation means has a shutter valve provided on the downstream side of the NOx storage reduction catalyst in the exhaust passage, and the exhaust passage is closed by the shutter valve. Thus, by repeating forward and reverse rotations of the electric assist turbocharger, the reducing agent is reciprocated in the vicinity of the NOx storage reduction catalyst.

  Therefore, when the traveling by the internal combustion engine is switched to the traveling by the electric motor, by closing the shutter valve and repeating the forward driving and the reverse driving of the electric assist turbocharger, the NOx storage reduction catalyst The unpurified NOx and the unused reducing agent do not flow downstream, and the reducing agent reciprocates and is stirred inside, promoting the reaction in the NOx storage reduction catalyst by the reducing agent, and storing it. Thus, the exhaust gas purification efficiency can be improved by improving the reduction efficiency of the NOx catalyst.

  In the exhaust emission control device for a hybrid vehicle of the present invention, the stirring means includes a volume chamber provided upstream or downstream of the NOx storage reduction catalyst in the exhaust passage, a piston provided in the volume chamber, An actuator for driving the piston; and a NOx storage reduction catalyst in the exhaust passage and a shutter valve provided on the downstream side of the volume chamber, and the actuator is closed with the exhaust passage. By reciprocating the piston, the reducing agent is reciprocated in the vicinity of the NOx storage reduction catalyst.

  Therefore, when the traveling by the internal combustion engine is switched to traveling by the electric motor, the shutter valve is closed and the piston is reciprocally driven by the actuator, so that the NOx storage reduction catalyst has unpurified NOx or unpurified downstream. The reductant used does not flow out, and the reductant reciprocates and is stirred inside, promoting the reaction of the reductant with the NOx storage reduction catalyst and improving the reduction efficiency of the stored NOx catalyst. Thus, exhaust purification efficiency can be improved.

  In the exhaust emission control device for a hybrid vehicle of the present invention, the agitation means includes a bypass passage that connects an upstream exhaust passage and a downstream exhaust passage of the NOx storage reduction catalyst, and an electric motor provided in the bypass passage. A switching valve that shuts off the upstream exhaust passage and the downstream exhaust passage of the NOx storage reduction catalyst and communicates the NOx storage reduction catalyst and the bypass passage; and The reductant is reciprocated in the vicinity of the NOx storage reduction catalyst by repeating forward and reverse rotations of the electric pump while the exhaust passage is blocked and the bypass passage is in communication.

  Therefore, when the traveling by the internal combustion engine is switched to the traveling by the electric motor, the upstream side exhaust passage and the downstream side exhaust passage of the NOx storage reduction catalyst are blocked by the switching valve, and the NOx storage reduction catalyst and the bypass passage. In this occlusion reduction type NOx catalyst, the reducing agent is reciprocated and stirred inside by rotating the electric pump forward and backward in a state where the electric pump is in communication. Thus, the reduction efficiency of the stored NOx catalyst can be improved and the exhaust purification efficiency can be improved.

  In the exhaust gas purification apparatus for a hybrid vehicle according to the present invention, the agitation means has a valve operating mechanism of the internal combustion engine, and repeats normal rotation and reverse rotation of the valve operating mechanism, whereby the reducing agent is stored in the NOx storage reduction catalyst. It is characterized by reciprocating near.

  Therefore, when the traveling by the internal combustion engine is switched to the traveling by the electric motor, the reductant is reciprocated and stirred in the NOx storage reduction catalyst by repeating forward and reverse rotation of the valve mechanism. Therefore, the reaction in the NOx storage reduction catalyst with the reducing agent is promoted, and the reduction efficiency of the NOx catalyst stored easily can be improved by using the existing valve mechanism without adding new equipment. The exhaust purification efficiency can be improved.

  According to the exhaust gas purification apparatus for a hybrid vehicle of the present invention, the reducing agent supplied to the NOx storage reduction catalyst is reciprocated and stirred by the stirring means during traveling by the electric motor. The reaction is promoted and NOx is efficiently reduced, so there is no need to provide an auxiliary catalyst downstream of the NOx storage reduction catalyst, and the outflow of unpurified NOx and reducing agent can be reliably prevented. The exhaust purification efficiency can be improved by improving the reduction efficiency of the occluded NOx catalyst.

  Hereinafter, an embodiment of an exhaust emission control device in a hybrid vehicle according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a schematic configuration diagram of an exhaust purification device in a hybrid vehicle according to a first embodiment of the present invention, FIG. 2 is a flowchart showing a NOx reduction process by the exhaust purification device in the hybrid vehicle of the first embodiment, and FIG. It is a schematic block diagram showing the hybrid vehicle to which the exhaust emission control device of Example 1 is applied.

  The vehicle on which the exhaust emission control device according to the first embodiment is mounted is a hybrid vehicle having a power train that uses a combination of two types of power sources, that is, an internal combustion engine and an electric motor. First, a description will be given of a hybrid vehicle equipped with the exhaust purification device of the first embodiment.

  In the hybrid vehicle of the first embodiment, as shown in FIG. 3, the vehicle is equipped with a diesel engine (DE) 11 as an internal combustion engine and a motor generator (MG) 12 as an electric motor as power sources. The vehicle is also equipped with a motor generator (MG) 13 that receives the output of the DE 11 and generates electric power. These DE11, MG12, and MG13 are connected by a power split mechanism 14. The power split mechanism 14 distributes the output of the DE 11 to the MG 13 and the drive wheel 15 and transmits the output from the MG 12 to the drive wheel 15 or to the drive wheel 15 via the speed reducer 16 and the drive shaft 17. It functions as a transmission related to the driving force.

  MG12 is an AC synchronous motor and is driven by AC power. The inverter 18 converts the electric power stored in the battery 19 from DC to AC and supplies it to the MG 12, and converts the electric power generated by the MG 13 from AC to DC and stores it in the battery 19. The MG 13 has basically the same configuration as the MG 12 described above, and has a configuration as an AC synchronous motor. In this case, the MG 12 mainly outputs the driving force, whereas the MG 13 mainly receives the output of the DE 11 and generates power.

  The MG 12 mainly generates a driving force, but can also generate electric power (regenerative power generation) by using the rotation of the driving wheels 15 and can also function as a generator. At this time, a brake (regenerative brake) acts on the drive wheel 15, and the vehicle can be braked by using this together with the foot brake or the engine brake. On the other hand, the MG 13 mainly receives the output of the DE 11 and generates power, but can also function as an electric motor that receives and drives the power of the battery 19 via the inverter 18.

  The crankshaft 20 of DE11 is provided with a crank position sensor 21 that detects the piston position and the engine speed. The crank position sensor 21 is connected to the engine ECU 22 and outputs a detection result. The drive shafts 23 and 24 of the MG 12 and MG 13 are provided with rotation speed sensors 25 and 26 for detecting the respective rotation positions and rotation speeds. Each rotation speed sensor 25, 26 is connected to a motor ECU 27 and outputs a detection result.

  The power split mechanism 14 described above is constituted by a planetary gear unit. That is, the power split mechanism (planetary gear unit) 14 includes a sun gear, a planetary gear arranged around the sun gear, a ring gear arranged on the outer periphery of the planetary gear, and a gear carrier holding the planetary gear, although not shown. It is composed of The crankshaft 20 of the DE 11 is coupled to the gear carrier via the central axis, and the output of the DE 11 is input to the gear carrier of the planetary gear unit 14. The MG 12 has a stator and a rotor inside, and the rotor is coupled to the ring gear, and the rotor and the ring gear are coupled to the speed reducer 16. The speed reducer 16 transmits the output input from the MG 12 to the ring gear of the planetary gear unit 14 to the drive shaft 17, and the MG 12 is always connected to the drive shaft 17.

  Similarly to MG12, MG13 has a stator and a rotor inside, and this rotor is coupled to the sun gear. That is, the output of the DE 11 is divided by the planetary gear unit 14 and input to the rotor of the MG 13 via the sun gear. The output of the DE 11 is divided by the planetary gear unit 14 and can be transmitted to the drive shaft 17 via a ring gear or the like.

  The entire planetary gear unit 14 can be used as a non-transmission transmission by controlling the amount of power generated by the MG 13 to control the rotation of the sun gear. That is, the output of DE 11 or MG 12 is output to the drive shaft 17 after being shifted by the planetary gear unit 14. Further, the rotational speed of the DE 11 can be controlled by controlling the power generation amount of the MG 13 (power consumption when it functions as a motor). Note that when the rotational speeds of the MG12 and MG13 are controlled, the motor ECU 27 controls the inverter 18 with reference to the outputs of the rotational sensors 25 and 26, whereby the rotational speed of the DE11 can also be controlled. is there.

  The various controls described above are controlled by a plurality of electronic control units (ECUs). The driving by DE11 and the driving by MG12 and MG13, which are characteristic as a hybrid vehicle, are comprehensively controlled by the main ECU. That is, the distribution of the output of DE 11 and the output of MG 12 and MG 13 is determined by main ECU 28, and control commands are output to engine ECU 22 and motor ECU 27 to control DE 11, MG 12, and MG 13.

  Further, the engine ECU 22 and the motor ECU 27 also output information on the DE 11, MG 12, and MG 13 to the main ECU 28. The main ECU 28 is also connected to a battery ECU 29 that controls the battery 19 and a brake ECU 30 that controls the brake. The battery ECU 29 monitors the state of charge of the battery 19 and outputs a charge request command to the main ECU 28 when the amount of charge is insufficient. Receiving the charge request, the main ECU 28 controls the MG 13 to generate power so that the battery 19 is charged. The brake ECU 30 controls the vehicle and controls the regenerative braking by the MG 12 together with the main ECU 28.

  Since the hybrid vehicle of the present embodiment is configured as described above, by distributing the necessary output required for the entire vehicle to DE11 and MG12 (MG13) while operating the hybrid vehicle, DE11 It is possible to satisfy the output required for the entire vehicle while controlling the driving state to a desired driving state.

  Next, the exhaust emission control device for the hybrid vehicle of the first embodiment will be described. In the exhaust gas purification apparatus for a hybrid vehicle according to the first embodiment, as shown in FIG. 1, a diesel engine (DE) 11 as an internal combustion engine is not shown, but a cylinder head is fastened on a cylinder block, and a plurality of cylinder bores are connected. The pistons are respectively fitted to be freely movable up and down. A crankcase is fastened to the lower part of the cylinder block, a crankshaft is rotatably supported in the crankcase, and each piston is connected to the crankshaft via a connecting rod.

  A plurality of combustion chambers 31 are constituted by a cylinder block, a cylinder head, and pistons, and the combustion chamber 31 is formed with an intake port 32 and an exhaust port 33 facing each other at the upper portion. The lower end portions of the intake valve 34 and the exhaust valve 35 are positioned with respect to 33. The intake valve 34 and the exhaust valve 35 are supported by the cylinder head so as to be movable along the axial direction, and are urged and supported in a direction to close the intake port 32 and the exhaust port 33. An intake cam shaft and an exhaust cam shaft are rotatably supported by the cylinder head, and the intake cam and the exhaust cam are in contact with upper end portions of the intake valve 32 and the exhaust valve 33 via a roller rocker arm.

  Therefore, when the intake camshaft and the exhaust camshaft rotate in synchronization with DE11, the intake cam and the exhaust cam operate the roller rocker arm, and the intake valve 34 and the exhaust valve 35 move up and down at a predetermined timing. 32 and the exhaust port 33 can be opened and closed to allow the intake port 32 and the combustion chamber 31 to communicate with the combustion chamber 31 and the exhaust port 33, respectively.

  An intake pipe (intake passage) 37 is connected to the intake port 32 via an intake manifold 36, and an air cleaner 38 is attached to an air intake port of the intake pipe 37. A throttle valve 39 is provided on the downstream side of the air cleaner 38. Each cylinder head is provided with an injector 41 capable of injecting light oil as fuel into each combustion chamber 31 at a high pressure. Each injector 41 is connected to a fuel pump 44 via a delivery pipe 42 and a fuel supply pipe 43, and the fuel pump 44 is driven by the DE 11. On the other hand, an exhaust pipe (exhaust passage) 46 is connected to the exhaust port 33 via an exhaust manifold 45.

  The intake pipe 37 and the exhaust pipe 46 are provided with an electric assist turbocharger (MAT) 47. In the electric assist turbocharger 47, a compressor 47a provided in an intake pipe 37 and a turbine 47b provided in an exhaust pipe 46 are integrally connected by a drive shaft 47c, and are forcibly driven by a drive motor 48. can do. An intercooler 49 is provided in the intake pipe 37 on the downstream side of the compressor 47a in the electric assist turbocharger 47 to cool the intake air that has been supercharged by the compressor 47a and whose temperature has risen.

  The exhaust pipe 46 is provided with an exhaust purification device 50 that purifies harmful substances contained in the exhaust gas. In the exhaust purification device 50, a first catalyst 51 and a second catalyst 52 are arranged in series. Has been configured. The first catalyst 51 is a NOx storage reduction catalyst that stores NOx in the exhaust gas when the exhaust air-fuel ratio is lean, and releases the stored NOx when the oxygen concentration in the exhaust gas decreases, The fuel is reduced by the added fuel (reducing oil in this embodiment) as a reducing agent. The second catalyst 52 is a NOx storage reduction catalyst having a particulate filter, which collects particulates (PM: particulates) in exhaust gas, particularly black smoke, and when the exhaust air-fuel ratio is lean. The NOx in the exhaust gas is occluded, and the occluded NOx is released when the oxygen concentration in the exhaust gas decreases, and is reduced by the added fuel.

  The DE 11 is provided with a high-pressure exhaust gas recirculation (EGR) device 53 that returns exhaust gas to the intake system. The high-pressure EGR device 53 connects an exhaust manifold 45 and an intake pipe 37 immediately before the intake manifold 36 to recirculate a part of the exhaust gas to the intake system, and an EGR provided in the EGR passage 54 The valve 55 and an EGR cooler 56 that is provided in the EGR passage 54 and cools the exhaust gas are configured.

  Further, the first catalyst 51 and the second catalyst 52 release the stored NOx when the oxygen concentration in the exhaust gas is reduced, and the released NOx is reduced by the fuel. A fuel addition valve 57 for injecting fuel (reducing agent) is provided in the cylinder head. The fuel addition valve 57 is connected to the fuel pump 44 through a fuel supply pipe 58, and an open / close valve 59 is provided in the fuel supply pipe 58.

  By the way, the engine ECU 22 can control various devices of the DE 11. In other words, the crank angle detected by the crank position sensor 21 is input to the engine ECU 22, and the engine ECU 22 determines each stroke of intake, compression, expansion (explosion), and exhaust in each cylinder based on the crank angle. In addition, the engine speed is calculated. Further, the accelerator opening detected by the accelerator position sensor 60 is input to the engine ECU 22, and the engine ECU 22 determines the fuel injection amount based on the accelerator opening and the engine speed. The engine ECU 22 controls the fuel pump 44 to maintain the fuel pressure in the delivery pipe 42 at a predetermined value, and controls the injector 41 to inject a predetermined amount of fuel into the combustion chamber 31 at a predetermined injection timing. can do.

  Further, the engine ECU 22 controls the drive of the electrically assisted turbocharger 47 based on the accelerator opening so that the output of the DE 11 can be adjusted. Further, the engine ECU 22 controls the drive of the EGR device 53 according to the engine operating state. That is, by opening and closing each EGR valve 55 in a predetermined operation state, exhaust gas is circulated as EGR gas to the intake system through the EGR passage 54, and the combustion temperature is lowered to suppress generation of NOx.

  Furthermore, the engine ECU 22 regenerates the first catalyst 51 and the second catalyst 52 that constitute the exhaust purification device 50 at a predetermined time. That is, a first temperature sensor 61 that measures the temperature of the exhaust gas is provided on the downstream side of the first catalyst 51, and a second temperature sensor that measures the temperature of the exhaust gas on the downstream side of the second catalyst 52. 62 is provided. Further, a differential pressure sensor 63 is provided for detecting a differential pressure between the pressure of the exhaust gas flowing into the exhaust purification device 50 and the pressure of the exhaust gas discharged from the exhaust purification device 50.

  Accordingly, when the DE 11 is operated at a lean air-fuel ratio, the first catalyst 51 and the second catalyst 52 occlude NOx in the exhaust gas. When the NOx occlusion amounts of the first catalyst 51 and the second catalyst 52 reach a predetermined value, the engine ECU 22 controls the fuel addition valve 57 and injects a predetermined amount of fuel into the exhaust port 33 as a reducing agent. Then, when fuel is supplied to the first catalyst 51 and the second catalyst 52 through the exhaust pipe 46, the oxygen concentration in the exhaust gas is reduced by the oxidation reaction, so that the NOx stored in each of the catalysts 51 and 52 is released. The released NOx and the fuel react to be reduced, and the exhaust gas is purified, whereby the first catalyst 51 and the second catalyst 52 are regenerated.

  In this case, the first catalyst 51 and the second catalyst 52 release the stored NOx, and an active temperature range is set in which the NOx can be reduced by the fuel. When each of the catalysts 51 and 52 is in this active temperature region The engine ECU 22 performs regeneration control. That is, when the exhaust gas temperature detected by the first temperature sensor 61 is in this activation temperature region, the engine ECU 22 injects a predetermined amount of fuel by the fuel addition valve 57 and regenerates the first catalyst 51 and the second catalyst 52. Execute control. On the other hand, when the exhaust gas temperature detected by the first temperature sensor 61 is not in the activation temperature region, the engine ECU 22 performs the temperature increase control of the first catalyst 51 and the second catalyst 52. In this temperature increase control, for example, fuel is injected by the fuel addition valve 57 to raise the catalyst temperature, and the exhaust gas temperature is raised by the oxidation reaction in the catalysts 51 and 52 to raise the temperature of the catalysts 51 and 52. The first catalyst 51 and the second catalyst 52 have a deterioration temperature at which the catalyst function deteriorates, and the engine ECU 22 determines whether the exhaust gas temperature detected by the second temperature sensor 62 does not exceed the deterioration temperature. Is monitoring. Further, the NOx occlusion amount occluded in the first catalyst 51 and the second catalyst 52 is estimated from the continued engine operating state.

  On the other hand, when the DE 11 is operated at a lean air-fuel ratio, the second catalyst 52 collects PM in the exhaust gas. When the PM collection amount of the second catalyst 52 reaches a predetermined value, the engine ECU 22 controls the fuel addition valve 57 to inject a predetermined amount of fuel into the exhaust port 33. Then, when fuel is supplied to the first catalyst 51 and the second catalyst 52 through the exhaust pipe 46, the catalyst temperature rises due to the oxidation reaction, so that the PM collected in the second catalyst 52 is burned and regenerated. Is done. In this case, when the pressure difference of the exhaust gas detected by the differential pressure sensor 63 exceeds a predetermined value set in advance, the engine ECU 22 generates a pressure loss in the second catalyst 52 and the trapped amount of PM is saturated. The fuel addition valve 57 injects a predetermined amount of fuel, and the regeneration control of the second catalyst 52 is executed.

  The fuel contains a sulfur (S) component, and this S component reacts with oxygen to become sulfur oxide (SOx), and this SOx is replaced with NOx instead of NOx in the first catalyst 51 and the second catalyst 52. Occluded. Therefore, when the PM collected by the second catalyst 52 is burned and regeneration control is executed, the engine ECU 22 adjusts the amount of fuel injected by the fuel addition valve 57 and is stored in the first catalyst 51 and the second catalyst 52. Reproduce after removing the SOx.

  By the way, in the 1st catalyst 51 and the 2nd catalyst 52 which have the function to occlude and reduce NOx, since a relatively large amount of NOx is suddenly released when fuel is supplied and regenerated, a part of NOx is appropriately Without being reduced, unpurified NOx flows out from the first catalyst 51 and the second catalyst 52. Further, when the fuel flows into the first catalyst 51 and the second catalyst 52 together with the exhaust gas, a part of the fuel slips through without reacting with the first catalyst 51 and the second catalyst 52 due to the flow velocity. That is, when the hybrid vehicle is driven by the MG 12, the flow of exhaust gas to the exhaust purification device 50 is stopped. Therefore, the fuel is supplied while the flow of exhaust gas to the first catalyst 51 and the second catalyst 52 to be regenerated is stopped. Even if added, the fuel is not sufficiently diffused in the exhaust passage, the contact between the catalysts 51 and 52 and the fuel becomes insufficient, and the stored NOx cannot be efficiently reduced, resulting in exhaust gas. The purification efficiency will decrease.

  Therefore, in the exhaust emission control device for the hybrid vehicle of the first embodiment, a predetermined amount of fuel is injected as a reducing agent from the fuel addition valve 57 to the exhaust port 33 during EV travel consisting of MG12 and MG13. When the first catalyst 51 and the second catalyst 52 are reached, the fuel is reciprocated in the vicinity of the first catalyst 51 and the second catalyst 52 (stirring means). In this case, in this embodiment, the electric assist turbocharger 47 is applied as the stirring means.

  Accordingly, when a predetermined amount of fuel is injected from the fuel addition valve 57 in a state where the electric assist turbocharger 47 is normally driven while the hybrid vehicle is driven only by the MG 12 and MG 13 with the DE 11 stopped, the injected fuel When the fuel gas flows into the exhaust system and reaches the exhaust gas purification device 50, the forward rotation and reverse rotation driving of the electric assist turbocharger 47 is repeated, so that the fuel is discharged into the exhaust gas purification device 50, that is, the first catalyst 51 and the first catalyst. The two-catalyst 52 moves reciprocally. Thereby, the fuel is sufficiently diffused in the first catalyst 51 and the second catalyst 52 to be regenerated, the fuel sufficiently contacts each catalyst 51, 52, and the stored NOx can be efficiently reduced, Outflow of unpurified NOx and fuel from each catalyst 51, 52 is suppressed.

  Here, the control of the NOx reduction process by the exhaust emission control device in the hybrid vehicle of the first embodiment will be described in detail based on the flowchart of FIG.

  In the control of the NOx reduction process by the exhaust purification device in the hybrid vehicle of the first embodiment, as shown in FIG. 2, it is determined in step S11 whether the start condition of the NOx reduction processing in the exhaust purification device 50 is satisfied. In this case, the engine ECU 22 detects the NOx occlusion amount of each of the catalysts 51 and 52 in the exhaust emission control device 50 based on the engine operating state after the DE 11 starts operation. By determining whether or not the determination value set based on the NOx saturation amounts 51 and 52 has been exceeded, it is determined whether or not the start condition for the NOx reduction process of the exhaust purification device 50 is satisfied. If the current NOx occlusion amount exceeds the determination value in step S11, it is determined that the NOx reduction processing of the exhaust purification device 50 should not be started yet, and this routine is exited without doing anything.

  In step S11, if the current NOx occlusion amount exceeds the determination value, the NOx reduction process of the exhaust purification device 50 should be started and the process proceeds to step S12. In this step S12, it is determined whether or not the EV traveling condition by the hybrid vehicle only by MG11 and MG12 is satisfied. Here, if the EV traveling condition is not satisfied, the process proceeds to step S13, where NOx reduction processing control in engine traveling is executed.

  On the other hand, if the EV traveling condition of the hybrid vehicle is satisfied in step S12, the NOx reduction process control is executed in the EV traveling in which DE11 is stopped after step S14. In step S14, it is determined whether the exhaust gas temperature T detected by the first temperature sensor 61 is higher than the catalyst activation temperature Tg. If the exhaust gas temperature T is equal to or lower than the catalyst activation temperature Tg, the catalyst is detected in step S15. Execute temperature rise control. That is, a predetermined amount of fuel is injected by the fuel addition valve 57, and the exhaust gas temperature is raised by the oxidation reaction in the first catalyst 51 and the second catalyst 52 to raise the temperature of each catalyst 51, 52.

  When the temperature of the first catalyst 51 and the second catalyst 52 is raised and it is determined in step S14 that the exhaust gas temperature T is higher than the catalyst activation temperature Tg, the fuel injection from each injector 41 in DE11 is performed in step S16. By stopping the operation, DE11 is stopped, and EV traveling is started in step S17. At this time, it is desirable to stably stop the DE 11 by closing the throttle valve 39 and the low pressure EGR valve 55 in the EGR device 53.

  Subsequently, in step S18, the electrically assisted turbocharger 47 is driven, and in step S19, the fuel addition valve 57 injects an amount of fuel that can reduce the NOx occluded by each of the catalysts 51 and 52. In S20, the reduction process timer starts counting up. In this case, the ECU 22 estimates the arrival time until the fuel injected by the fuel addition valve 57 to the exhaust port 33 reaches the exhaust purification device 50 based on the volume of the exhaust system and the rotational speed of the electrically assisted turbocharger 47. In step S21, it is determined whether or not the count time of the reduction process timer has passed this arrival time, and waits until the count time has passed the arrival time. When the count time of the reduction process timer has reached the arrival time in step S21, the forward rotation driving and the reverse rotation driving of the electric assist turbocharger 47 are repeatedly performed in step S22.

  When the DE 11 is operated at a lean air-fuel ratio, the first catalyst 51 and the second catalyst 52 occlude NOx in the exhaust gas. When the NOx occlusion amounts of the first catalyst 51 and the second catalyst 52 reach a predetermined value, a predetermined amount of fuel is injected into the exhaust port 33 by the fuel addition valve 61 with the DE 11 stopped. Then, the fuel is supplied to the first catalyst 51 and the second catalyst 52 through the exhaust pipe 46, and the NOx occluded in each of the catalysts 51 and 52 is released by the reduction of the oxygen concentration in the exhaust gas due to the oxidation reaction. The NOx and fuel that have been reacted react and reduce, and the exhaust gas is purified.

  In this case, when the fuel injected from the fuel addition valve 57 reaches the exhaust purification device 50, the exhaust gas containing the fuel is converted into the exhaust purification device by repeatedly rotating the electric assist turbocharger 47 forward and backward. 50, that is, reciprocating movement within the first catalyst 51 and the second catalyst 52 repeatedly. Therefore, the movement time for the fuel to move in the exhaust purification device 50 becomes longer, and the processing efficiency can be improved by extending the NOx reduction processing time. Therefore, the fuel is sufficiently diffused in the first catalyst 51 and the second catalyst 52, and the NOx occluded by effectively utilizing the fuel is efficiently reduced. Purification NOx and fuel outflow are suppressed.

  In step S23, it is determined whether the count time of the reduction process timer has passed a preset process time. If the count time of the reduction process timer has passed this process time, in step S24, the electric assist The turbocharger 47 is stopped, and the count of the reduction process timer is cleared in step S25. Note that the processing time described in step S23 is a time during which the first catalyst 51 and the second catalyst 52 that have become saturated due to occlusion of NOx can be completely regenerated with fuel, and is obtained in advance through experiments or the like.

  As described above, in the exhaust purification device for the hybrid vehicle of the first embodiment, the exhaust purification device 50 including the first catalyst 51 and the second catalyst 52 that can store and reduce NOx in the exhaust gas in the exhaust pipe 46 is provided. In addition, a fuel addition valve 57 for supplying fuel as a reducing agent to each of the catalysts 51 and 52 is provided to drive the electrically assisted turbocharger during EV travel by the MG 12 and MG 13 that have stopped the DE 11, and the fuel addition valve The fuel as a reducing agent is supplied to the exhaust gas purification device 50 by injecting a predetermined amount of fuel from the engine 57 to the exhaust port 33. At this time, the forward drive and the reverse drive of the electric assist turbocharger are repeated. The fuel is reciprocated in the first catalyst 51 and the second catalyst 52.

  Accordingly, when the DE 11 is stopped and a predetermined amount of fuel is injected from the fuel addition valve 61 when the hybrid vehicle is driven only by the MG 12 and the MG 13, NOx is released from the respective catalysts 51 and 52 due to a decrease in the oxygen concentration. The released NOx reacts with the fuel and is reduced. At this time, some unpurified NOx and reducing agent flow out from the catalysts 51 and 52. When the fuel reaches the catalysts 51 and 52, the exhaust gas containing the fuel reciprocates inside. It becomes. As a result, the fuel is sufficiently diffused in the first catalyst 51 and the second catalyst 52, and the NOx stored by effectively utilizing the fuel is efficiently reduced. Purified NOx and fuel are not discharged to the outside, and an auxiliary catalyst for treating the unpurified NOx and the fuel that has passed through the catalyst 51 and 52 becomes unnecessary, improving the reduction efficiency of the stored NOx catalyst. Thus, exhaust purification efficiency can be improved.

  In the present embodiment, the agitation means is the electric assist turbocharger 47, and the fuel is transferred to the exhaust gas purification device 50 by the forward rotation drive of the electric assist turbocharger 47. The fuel is reciprocated in the exhaust purification device 50 by driving forward and backward. Therefore, by using the electric assist turbocharger 47 that is an existing facility, it is possible to improve the reduction efficiency of the NOx catalyst that is easily occluded without installing a separate stirring device, and to improve the exhaust purification efficiency. .

  In the first embodiment, the electric assist turbocharger 47 is provided as a stirring means. In addition to this, a shutter valve is provided in the exhaust pipe 46 on the downstream side of the exhaust purification device 50, and the exhaust pipe is provided by this shutter valve. The fuel may be reciprocated in the exhaust purification device 50 by repeating forward and reverse rotations of the electrically assisted turbocharger 47 with the 46 closed. In this case, exhaust purification efficiency can be improved by reliably preventing the unpurified NOx and fuel discharged from the first catalyst 51 and the second catalyst 52 from being discharged by the shutter valve.

  FIG. 4 is a schematic configuration diagram of an exhaust emission control device in a hybrid vehicle according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the exhaust emission control device in the hybrid vehicle of the second embodiment, as shown in FIG. 4, the exhaust pipe 46 is provided with an exhaust emission control device 50 including a first catalyst 51 and a second catalyst 52, and the first catalyst. 51 is an NOx storage reduction catalyst, and the second catalyst 52 is an NOx storage reduction catalyst having a particulate filter. A fuel addition valve 57 for injecting fuel (reducing agent) into the exhaust port 33 is provided in the cylinder head. When the NOx occlusion amounts of the first catalyst 51 and the second catalyst 52 become saturated, this fuel is supplied. By injecting fuel through the addition valve 57, the concentration of oxygen in the exhaust gas is reduced to release the stored NOx, and the released NOx is reduced by the fuel.

  In the exhaust emission control device for the hybrid vehicle of the second embodiment, a predetermined amount of fuel is injected as a reducing agent from the fuel addition valve 57 to the exhaust port 33, and the injected fuel is supplied to the first catalyst 51 and the second catalyst 52. When it reaches, this fuel is reciprocated in the vicinity of the first catalyst 51 and the second catalyst 52 (stirring means). In this case, in this embodiment, as a stirring means, a volume chamber 71 provided on the downstream side of the exhaust purification device 50 in the exhaust pipe 46, a piston 72 provided in the volume chamber 71, and the piston 72 are driven. An actuator 73 and an exhaust purification device 50 in the exhaust pipe 46 and a shutter valve 74 provided on the downstream side of the volume chamber 71 are applied.

  That is, a tubular volume chamber 71 is branched from the exhaust pipe 46 on the downstream side of the exhaust purification device 50, and a piston 72 is movably fitted in the volume chamber 71, and the end of the volume chamber 71 is also connected. The part is provided with an actuator 73 for driving the piston 72. The actuator 73 is biased and supported by the biasing force of the spring 75 so that the piston 72 approaches the exhaust pipe 46, and is separated from the exhaust pipe 46 by the vacuum device 76 against the biasing force of the spring 75. It is possible to move. The engine ECU 22 can control the actuator 73 (vacuum device 76) and the shutter valve 74 provided in the exhaust pipe 46.

  Therefore, when DE11 stops and the hybrid vehicle EV travels only by MG12 and MG13, a predetermined amount of fuel is injected from fuel addition valve 57, and the injected fuel flows into the exhaust system and reaches exhaust purification device 50. Thus, after closing the exhaust pipe 46 by the shutter valve 74, the piston 72 is reciprocated by the actuator 73, whereby negative pressure and positive pressure act alternately on the exhaust pipe 46 via the volume chamber 71, and the fuel is exhausted. The purification device 50 moves in a reciprocating manner within the first catalyst 51 and the second catalyst 52. Thereby, the fuel is sufficiently diffused in the first catalyst 51 and the second catalyst 52 to be regenerated, the fuel sufficiently contacts each catalyst 51, 52, and the stored NOx can be efficiently reduced, Outflow of unpurified NOx and fuel from each catalyst 51, 52 is suppressed.

  In this case, a small amount of unpurified NOx and fuel flow out from the first catalyst 51 and the second catalyst 52, but the downstream side of the exhaust purification device 50 in the exhaust pipe 46 is closed from the shutter valve 74, so NOx and fuel are not discharged to the outside, and the exhaust gas is reliably purified while reciprocating through the catalysts 51 and 52.

  After DE11 is stopped, the electric-assist turbocharger 47 is driven to transfer the fuel injected from the fuel addition valve 57 to the exhaust purification catalyst 50, or after the fuel is injected from the fuel addition valve 57. The DE 11 may be stopped when the fuel reaches the exhaust purification catalyst 50.

  As described above, in the exhaust emission control device in the hybrid vehicle according to the second embodiment, the exhaust emission control device 50 including the first catalyst 51 and the second catalyst 52 that can store and reduce NOx in the exhaust gas in the exhaust pipe 46 is provided. In addition, a fuel addition valve 57 for supplying fuel as a reducing agent to each of the catalysts 51 and 52 is provided, and a volume chamber 71 in which the piston 72 can move is connected to the exhaust pipe 46 on the downstream side of the exhaust purification device 50. At the same time, an actuator 73 for driving the piston 72 is connected, and a shutter valve 74 is provided downstream of the exhaust purification device 50 and the volume chamber 71 in the exhaust pipe 46.

  Therefore, when the DE 11 is stopped and a predetermined amount of fuel is injected from the fuel addition valve 57 when the hybrid vehicle is driven only by the MG 12 and the MG 13, NOx is released from the respective catalysts 51 and 52 due to a decrease in the oxygen concentration. The released NOx reacts with the fuel and is reduced. At this time, a part of the unpurified NOx and the reducing agent flows out from the catalysts 51 and 52, but when the fuel reaches the catalysts 51 and 52, In addition, the piston 73 is reciprocated by the actuator 73 after the shutter valve 74 is closed, so that negative pressure and positive pressure act alternately on the exhaust pipe 46 via the volume chamber 71, and the exhaust gas containing fuel is the first. It will reciprocate within the catalyst 51 and the second catalyst 52. As a result, the fuel is sufficiently diffused in the first catalyst 51 and the second catalyst 52, and the NOx stored by effectively utilizing the fuel is efficiently reduced. Purified NOx and fuel are not discharged to the outside, and an auxiliary catalyst for treating the unpurified NOx and the fuel that has passed through the catalyst 51 and 52 becomes unnecessary, improving the reduction efficiency of the stored NOx catalyst. Thus, exhaust purification efficiency can be improved.

  The second catalyst 52 collects PM in the exhaust gas. When the NOx reduction process is performed, when the shutter valve 74 is closed and the piston 73 is reciprocated by the actuator 73, the negative pressure and the positive pressure are increased. PM clogging in the second catalyst 52 can be suppressed via the chamber 71 and the exhaust pipe 46. Further, when the second catalyst 52 is regenerated, the piston 72 is reciprocated by the actuator 73, so that the PM trapped in the second catalyst 52 can be stably burned.

  FIG. 5 is a schematic configuration diagram of an exhaust emission control device in a hybrid vehicle according to Embodiment 3 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the exhaust purification device for the hybrid vehicle of the third embodiment, as shown in FIG. 5, the exhaust pipe 46 is provided with an exhaust purification device 50 including a first catalyst 51 and a second catalyst 52, and the first catalyst. 51 is an NOx storage reduction catalyst, and the second catalyst 52 is an NOx storage reduction catalyst having a particulate filter. A fuel addition valve 57 for injecting fuel (reducing agent) into the exhaust port 33 is provided in the cylinder head. When the NOx occlusion amounts of the first catalyst 51 and the second catalyst 52 become saturated, this fuel is supplied. By injecting fuel through the addition valve 57, the concentration of oxygen in the exhaust gas is reduced to release the stored NOx, and the released NOx is reduced by the fuel.

  In the exhaust emission control device for the hybrid vehicle of the third embodiment, a predetermined amount of fuel is injected as a reducing agent from the fuel addition valve 57 to the exhaust port 33, and the injected fuel is supplied to the first catalyst 51 and the second catalyst 52. When it reaches, this fuel is reciprocated in the vicinity of the first catalyst 51 and the second catalyst 52 (stirring means). In this case, in this embodiment, as the agitation means, a bypass passage 81 connecting the upstream exhaust passage and the downstream exhaust passage of the exhaust purification device 50 in the exhaust pipe 46 is provided, and the exhaust purification device 50 and the exhaust pipe are connected. 46, switching valves 82 and 83 communicating with the bypass passage 81 and an electric pump 84 are provided in the bypass passage 81.

  That is, the exhaust pipe 46 is provided with a bypass passage 81 so as to bypass the exhaust purification device 50, and the first switching valve is provided at the upstream side of the exhaust purification device 50 and the upstream end of the bypass passage 81 in the exhaust pipe 46. On the other hand, a second switching valve 82 is provided on the exhaust pipe 46 at the downstream side of the exhaust purification device 50 and at the downstream end of the bypass passage 81. An electric pump 84 is provided in the bypass passage 81. Each of the switching valves 82 and 83 and the electric pump 84 can be driven and controlled by the engine ECU 22, and normally the exhaust pipe 46 and the exhaust purification device 50 are opened by the switching valves 82 and 83. By operating the switching valves 82 and 83, the exhaust pipe 46 and the exhaust purification device 50 are shut off, and the exhaust purification device 50 and the bypass passage 81 are communicated to repeat the forward drive and reverse drive of the electric pump 84. Thus, the exhaust gas can be reciprocated in the exhaust purification device 50.

  Therefore, when DE11 stops and the hybrid vehicle EV travels only by MG12 and MG13, a predetermined amount of fuel is injected from fuel addition valve 57, and the injected fuel flows into the exhaust system and reaches exhaust purification device 50. Thus, the switching pipes 82 and 83 shut off the exhaust pipe 46 and the exhaust purification device 50, and the exhaust purification device 50 and the bypass passage 81 are communicated to form a loop passage. In this state, by driving the electric pump 84, the pressure acts on the exhaust purification device 50 via the bypass passage 81, and the exhaust gas containing the fuel that has reached the first catalyst 51 and the second catalyst 52 is discharged. It will reciprocate within the first catalyst 51 and the second catalyst 52. Thereby, the fuel is sufficiently diffused in the first catalyst 51 and the second catalyst 52 to be regenerated, the fuel sufficiently contacts each catalyst 51, 52, and the stored NOx can be efficiently reduced, Outflow of unpurified NOx and fuel from each catalyst 51, 52 is suppressed.

  In this case, a small amount of unpurified NOx and fuel flow out from the first catalyst 51 and the second catalyst 52. However, since the downstream side of the exhaust purification device 50 is connected to the bypass passage 71 by the switching valve 73, the unpurified NOx and the fuel flow out. NOx and fuel are not discharged to the outside and are reliably purified while reciprocating the catalysts 51 and 52.

  As described above, in the exhaust gas purification apparatus for the hybrid vehicle of the third embodiment, the exhaust gas purification apparatus 50 including the first catalyst 51 and the second catalyst 52 that can store and reduce NOx in the exhaust gas in the exhaust pipe 46 is provided. In addition, a fuel addition valve 61 for supplying fuel as a reducing agent to each of the catalysts 51 and 52 is provided, and a bypass passage that connects the upstream exhaust passage and the downstream exhaust passage of the exhaust purification device 50 in the exhaust pipe 46 81 is provided, the exhaust purification device 50 and the exhaust pipe 46 are shut off, switching valves 82 and 83 communicating with the bypass passage 81 are provided, and an electric pump 84 is provided in the bypass passage 81.

  Accordingly, when the DE 11 is stopped and a predetermined amount of fuel is injected from the fuel addition valve 57 and reaches the exhaust purification device 50 during EV travel of the hybrid vehicle using only the MG 12 and MG 13, the exhaust pipe 46 is driven by the switching valves 82 and 83. And the exhaust gas purification device 50 are cut off, the exhaust gas purification device 50 and the bypass passage 81 are connected to form a loop passage, and the forward rotation and reverse rotation driving of the electric pump 84 are repeated, so that the exhaust gas containing fuel is It will reciprocate within the first catalyst 51 and the second catalyst 52. As a result, the fuel is sufficiently diffused in the first catalyst 51 and the second catalyst 52, and the NOx stored by effectively utilizing the fuel is efficiently reduced. Purified NOx and fuel are not discharged to the outside, and an auxiliary catalyst for treating the unpurified NOx and the fuel that has passed through the catalyst 51 and 52 becomes unnecessary, improving the reduction efficiency of the stored NOx catalyst. Thus, exhaust purification efficiency can be improved.

  6-1 is a schematic configuration diagram of an exhaust purification device in a hybrid vehicle according to a fourth embodiment of the present invention, and FIG. 6-2 is a schematic diagram for explaining the operation of the exhaust purification device in the hybrid vehicle of the fourth embodiment. . In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the exhaust emission control device in the hybrid vehicle of the fourth embodiment, as shown in FIG. 6A, the exhaust pipe 46 is provided with an exhaust emission control device 50 including a first catalyst 51 and a second catalyst 52. The first catalyst 51 is an NOx storage reduction catalyst, and the second catalyst 52 is an NOx storage reduction catalyst having a particulate filter. A fuel addition valve 57 for injecting fuel (reducing agent) to the exhaust port 33 is provided. When the NOx occlusion amounts of the first catalyst 51 and the second catalyst 52 become saturated, this fuel addition valve 57 is provided. By injecting the fuel, the NOx occluded is released by reducing the oxygen concentration in the exhaust gas, and the released NOx is reduced by the fuel.

  In the exhaust emission control device for the hybrid vehicle of the third embodiment, a predetermined amount of fuel is injected as a reducing agent from the fuel addition valve 57 to the exhaust port 33, and the injected fuel is supplied to the first catalyst 51 and the second catalyst 52. When it reaches, this fuel is reciprocated in the vicinity of the first catalyst 51 and the second catalyst 52 (stirring means). In this case, in this embodiment, the valve operating mechanism of DE11 is applied as the stirring means.

  Accordingly, as shown in FIGS. 6A and 6B, when the exhaust purification device 50 (the first catalyst 51 and the second catalyst 52) is regenerated, a predetermined amount of fuel is injected from the fuel addition valve 57 and injected. When the discharged fuel flows into the exhaust system and reaches the exhaust gas purification device 50, the DE 11 is stopped to bring the hybrid vehicle into an EV running state using only the MG 12 and the MG 13, and the MG 12 moves the DE 11 through the crankshaft 20. By transmitting driving force to the valve mechanism and repeating forward and reverse driving of the crankshaft 20, exhaust pressure is applied to the exhaust purification device 50 through the exhaust pipe 46 by reciprocating movement of the piston, and the first catalyst 51 and The exhaust gas containing the fuel that has reached the second catalyst 52 is reciprocated in the first catalyst 51 and the second catalyst 52. Thereby, the fuel is sufficiently diffused in the first catalyst 51 and the second catalyst 52 to be regenerated, the fuel sufficiently contacts each catalyst 51, 52, and the stored NOx can be efficiently reduced, Outflow of unpurified NOx and fuel from each catalyst 51, 52 is suppressed.

  As described above, in the exhaust emission control device for the hybrid vehicle according to the fourth embodiment, the exhaust emission control device 50 including the first catalyst 51 and the second catalyst 52 that can store and reduce NOx in the exhaust gas in the exhaust pipe 46 is provided. In addition, a fuel addition valve 61 for supplying fuel as a reducing agent to each of the catalysts 51 and 52 is provided, and a predetermined amount of fuel injected from the fuel addition valve 57 is purified by exhaust during EV travel of the hybrid vehicle with the DE 11 stopped. When reaching the device 50, the MG 12 repeats the forward rotation and reverse rotation of the valve mechanism of the DE 11 via the crankshaft 20, so that the exhaust gas containing fuel is discharged from the first catalyst 51 and the second by the exhaust pressure. A reciprocal movement is made in the catalyst 52.

  Accordingly, the DE 11 is stopped, and the exhaust gas containing fuel reciprocates in the first catalyst 51 and the second catalyst 52 when the hybrid vehicle is traveling on EV. The fuel in the first catalyst 51 and the second catalyst 52 The NOx stored by effectively utilizing the fuel is efficiently reduced, and the unpurified NOx and fuel are not discharged to the outside from the catalysts 51 and 52. An auxiliary catalyst for treating the unpurified NOx and the fuel that has passed through is not required downstream of the catalysts 51 and 52, and the reduction efficiency of the stored NOx catalyst can be improved to improve the exhaust purification efficiency.

  Further, in this embodiment, the stirring means is a valve mechanism of DE11, and the valve mechanism is driven to rotate forward and backward so that the exhaust gas containing the fuel is reciprocated in the exhaust purification device 50. I have to. Therefore, by utilizing a valve mechanism that is an existing facility, it is possible to improve the reduction efficiency of the NOx catalyst that has been occluded easily without installing a separate stirring device, thereby improving the exhaust purification efficiency.

  In each of the above-described embodiments, the fuel addition valve 57 as the reducing agent supply means is provided in the cylinder head and the fuel is injected into the exhaust port 33. However, the mounting position is not limited to this, and the exhaust purification device 50 is not limited thereto. As long as it is an exhaust system on the upstream side. In the case of the third embodiment described above, the first catalyst 51 and the second catalyst 51 are provided by providing the exhaust pipe 46 on the upstream side of the exhaust purification device 50 and the upstream end of the bypass passage 81 at substantially the same position as the first switching valve 82. At the time of regeneration of the catalyst 52, by switching the switching valves 81 and 82 and then injecting fuel as a reducing agent, it is not necessary to estimate the arrival position of the injected fuel, and the purification efficiency can be further improved. .

  In each of the embodiments, the exhaust purification device 50 includes the first catalyst 51 as the NOx storage reduction catalyst and the second catalyst 52 as the NOx storage reduction catalyst having the particulate filter. The catalyst may be an oxidation catalyst.

  As described above, the exhaust emission control device in the hybrid vehicle according to the present invention processes the reductant supplied to the exhaust system while reciprocating in the vicinity of the NOx storage reduction catalyst, and includes an internal combustion engine, an electric motor, It is useful when applied to a hybrid vehicle that can be driven using a power source.

1 is a schematic configuration diagram of an exhaust emission control device in a hybrid vehicle according to a first embodiment of the present invention. 3 is a flowchart showing NOx reduction processing by the exhaust purification device in the hybrid vehicle of the first embodiment. 1 is a schematic configuration diagram illustrating a hybrid vehicle to which an exhaust emission control device according to a first embodiment is applied. It is a schematic block diagram of the exhaust gas purification apparatus in the hybrid vehicle which concerns on Example 2 of this invention. It is a schematic block diagram of the exhaust gas purification apparatus in the hybrid vehicle which concerns on Example 3 of this invention. It is a schematic block diagram of the exhaust gas purification apparatus in the hybrid vehicle which concerns on Example 4 of this invention. FIG. 10 is a schematic diagram for explaining the operation of an exhaust emission control device in a hybrid vehicle of a fourth embodiment.

Explanation of symbols

11 Diesel engine, DE (internal combustion engine)
12, 13 Motor generator, MG (electric motor)
14 Power distribution mechanism (planetary gear unit)
19 Battery 22 Engine ECU (passing time estimation means)
27 Motor ECU
28 Main ECU
29 Battery ECU
37 Intake pipe (intake passage)
39 Throttle valve 46 Exhaust pipe (exhaust passage)
47 Electric assist turbocharger (stirring means)
50 Exhaust purification device 51 First catalyst (NOx storage reduction catalyst)
52 2nd catalyst (NOx storage reduction catalyst)
57 Fuel addition valve (reducing agent supply means)
71 Volume chamber (stirring means)
72 piston (stirring means)
73 Actuator (stirring means)
74 Shutter valve (stirring means)
81 Bypass passage (circulation means)
82, 83 Switching valve (circulation means)
84 Electric pump (circulation means)

Claims (6)

  In a hybrid vehicle capable of running using an internal combustion engine and an electric motor as a power source, a storage reduction type NOx catalyst provided in an exhaust passage of the internal combustion engine and capable of storing and reducing NOx in exhaust gas, and the storage reduction type A reducing agent supplying means for supplying a reducing agent to the NOx catalyst; and an agitating means for reciprocating the reducing agent supplied by the reducing agent supplying means in the vicinity of the NOx storage reduction catalyst when the vehicle is driven by the electric motor. An exhaust emission control device for a hybrid vehicle characterized by the above.   2. The exhaust gas purification apparatus for a hybrid vehicle according to claim 1, wherein the stirring unit includes an electric assist turbocharger provided in the intake passage and the exhaust passage, An exhaust emission control device for a hybrid vehicle, wherein the reductant is reciprocated in the vicinity of the NOx storage reduction catalyst by repeating reverse rotation.   3. The exhaust gas purification apparatus for a hybrid vehicle according to claim 2, wherein the agitation unit includes a shutter valve provided on a downstream side of the NOx storage reduction catalyst in the exhaust passage, and the exhaust passage is opened by the shutter valve. An exhaust emission control device in a hybrid vehicle, wherein the reducing agent is reciprocated in the vicinity of the NOx storage reduction catalyst by repeating forward and reverse rotations of the electrically assisted turbocharger in a closed state.   2. The exhaust gas purification apparatus for a hybrid vehicle according to claim 1, wherein the stirring unit is provided in a volume chamber provided upstream or downstream of the NOx storage reduction catalyst in the exhaust passage, and in the volume chamber. A piston, an actuator for driving the piston, and the NOx storage reduction catalyst in the exhaust passage and a shutter valve provided on the downstream side of the volume chamber, the exhaust passage being closed by the shutter valve The exhaust purification apparatus in a hybrid vehicle is characterized in that the reductant is reciprocated in the vicinity of the NOx storage reduction catalyst by reciprocating the piston by the actuator.   2. The exhaust gas purification apparatus for a hybrid vehicle according to claim 1, wherein the stirring unit is provided in a bypass passage that connects an upstream exhaust passage and a downstream exhaust passage of the NOx storage reduction catalyst, and the bypass passage. And a switching valve that shuts off the upstream exhaust passage and the downstream exhaust passage of the NOx storage reduction catalyst and communicates the NOx storage reduction catalyst with the bypass passage, The reductant is reciprocated in the vicinity of the NOx storage reduction catalyst by shutting off the exhaust passage by a switching valve and repeating forward and reverse rotation of the electric pump in a state where the bypass passage is communicated. An exhaust purification device for a hybrid vehicle.   2. The exhaust gas purification apparatus for a hybrid vehicle according to claim 1, wherein the agitation unit includes a valve operating mechanism of the internal combustion engine, and repeats normal rotation and reverse rotation of the valve operating mechanism, whereby the reducing agent is stored and reduced. An exhaust emission control device for a hybrid vehicle, wherein the exhaust gas purification device reciprocates in the vicinity of a NOx catalyst.

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