WO2010134212A1

WO2010134212A1 - Exhaust purification apparatus for a hybrid vehicle

Info

Publication number: WO2010134212A1
Application number: PCT/JP2009/059823
Authority: WO
Inventors: 浅沼孝充; 西岡寛真; 今井大地; 中田有香; 梅本寿丈; 吉田耕平
Original assignee: トヨタ自動車株式会社
Priority date: 2009-05-22
Filing date: 2009-05-22
Publication date: 2010-11-25

Abstract

A NO_X storage catalyst (13) is provided inside the exhaust passage of an engine (1) of a hybrid vehicle that can be driven using an engine (1) and/or an electric motor (23). The NO_X storage catalyst (13) absorbs NO_X, which is contained in the exhaust, when the air-fuel ratio of the inflowing exhaust gas is lean, and discharges the absorbed NO_X when the air-fuel ratio of the inflowing exhaust gas is rich. If the amount of NO_X absorbed by the NO_X storage catalyst (13) is greater than a predetermined amount when engine operation is stopped and driving using the electric motor is started, NO_X is discharged from the NO_X storage catalyst (13) by making the air-fuel ratio of the exhaust gas that flows into the NO_X storage catalyst (13) rich.

Description

Exhaust gas purification device for hybrid vehicle

The present invention relates to an exhaust emission control device for a hybrid vehicle.

When the air-fuel ratio of the exhaust gas flowing into the engine exhaust passage is lean, the NO _X contained in the exhaust gas is occluded, and when the air-fuel ratio of the exhaust gas flowing in becomes the stoichiometric air-fuel ratio or rich, the stored NO _X is released. An NO _X purification catalyst is disposed, and an electric motor capable of generating vehicle driving force separately from the vehicle driving force by the engine and generating electric power by the engine is provided, and premixed combustion is performed in the engine low speed and low load region. In addition, a hybrid vehicle is known in which electric power is generated by an electric motor and diffusion combustion is performed in an engine high load region and a high speed region and a part of vehicle driving force is carried by the electric motor (see Patent Document 1). .
In this hybrid vehicle, when the NO _X adsorption amount adsorbed by the NO _X storage catalyst increases, the engine output is reduced in order to reduce the NO _X amount discharged from the combustion chamber. At this time, the vehicle driving force by the electric motor is increased so that the vehicle driving force does not decrease. Thus is the vehicle driving force is controlled by an electric motor to a hybrid vehicle that adjusts the NO _X adsorption amount to _the NO _X storage catalyst, thereby adsorbing a large amount of the NO _X as possible the NO _X storing catalyst I am trying to get it.

JP 2005-51893 A

By the way, in such a hybrid vehicle, after the operation of the engine is temporarily stopped and the vehicle is driven by the electric motor, when the operation of the engine is resumed in order to drive the vehicle again by the engine, the operation of the engine is resumed. Immediately after that, a large amount of NO _X is discharged from the combustion chamber. _The NO _X storage the discharged NO _X from the combustion chamber to the time _the NO _X storage catalyst is already reduced ability to insert a new NO _X in the _the NO _X storage catalyst has occluded a large amount of the NO _X This causes a problem that the catalyst cannot be fully occluded.
However, in the known hybrid vehicle described above, the engine is always operated during vehicle operation, and the engine is not stopped during vehicle operation. Therefore, in the above-described known hybrid vehicle, the above-described problem caused by the engine being stopped while the vehicle is operating is naturally not taken into consideration.
An object of the present invention is to provide an exhaust purifying apparatus for a hybrid vehicle which can satisfactorily purify NO _X when the operation of the engine while the vehicle is driving is resumed.

According to the present invention, an electric device capable of generating a vehicle driving force separately from a vehicle driving force by the engine and generating electric power by the engine is provided, and the vehicle is driven by one or both of the engine and the electric device. in the exhaust purification device possible hybrid vehicle, in the engine exhaust passage, the air-fuel ratio is the stoichiometric air-fuel ratio of the exhaust gas air-fuel ratio of the inflowing exhaust gas when the lean of occluding NO _X contained in the exhaust gas inflow or becomes rich place the NO _X storing catalyst to release the occluded NO _X, is _the NO _X storage amount stored in the NO _X storage catalyst when to stop the operation of the engine starts to drive the vehicle by the electric device so as to release the NO _X from the NO _X storing catalyst and the air-fuel ratio of the exhaust gas flowing into the NO _X storage catalyst rich when more than storage amount is predetermined There.

Since the NO _X storage amount when the operation of the engine is resumed is kept low, the NO _X discharged from the combustion chamber at this time can be purified well.

FIG. 1 is an overall view of an internal combustion engine.
FIG. 2 is a view for explaining the NO _X absorption action.
FIG. 3 is a graph showing the relationship between the NO _X storage amount and the NO _X storage speed.
Figure 4 is a diagram illustrating a map of exhaust amount of NO _X.
FIGS. 5A and 5B are diagrams for explaining the charge amount SOC of the battery.
FIG. 6 is a flowchart for performing operation control.
FIG. 7 is a flowchart for performing operation control.
FIG. 8 is a diagram showing another embodiment of the electric device.

FIG. 1 shows an overall view of a compression ignition type internal combustion engine.
Referring to FIG. 1, 1 is an engine body, 2 is a combustion chamber of each cylinder, 3 is an electronically controlled fuel injection valve for injecting fuel into each combustion chamber 2, 4 is an intake manifold, and 5 is an exhaust manifold. Respectively. The intake manifold 4 is connected to the outlet of the compressor 7a of the exhaust turbocharger 7 via the intake duct 6, and the inlet of the compressor 7a is connected to the air cleaner 9 via the intake air amount detector 8 for detecting the intake air amount. The A throttle valve 10 driven by a step motor is disposed in the intake duct 6, and a cooling device 11 for cooling intake air flowing through the intake duct 6 is disposed around the intake duct 6. In the embodiment shown in FIG. 1, the engine cooling water is guided into the cooling device 11, and the intake air is cooled by the engine cooling water. On the other hand, the exhaust manifold 5 is connected to the inlet of the exhaust turbine 7 b of the exhaust turbocharger 7, and the outlet of the exhaust turbine 7 b is connected to the NO _X storage catalyst 13 via the exhaust pipe 12. Temperature sensor 14 for detecting the temperature of the NO _X storing catalyst 13 is attached to the the NO _X storing catalyst 13.
The exhaust manifold 5 and the intake manifold 4 are connected to each other via an exhaust gas recirculation (hereinafter referred to as EGR) passage 15, and an electronically controlled EGR control valve 16 is disposed in the EGR passage 15. A cooling device 17 for cooling the EGR gas flowing in the EGR passage 15 is disposed around the EGR passage 15. In the embodiment shown in FIG. 1, the engine cooling water is guided into the cooling device 17, and the EGR gas is cooled by the engine cooling water. On the other hand, each fuel injection valve 3 is connected to a common rail 19 through a fuel supply pipe 18. Fuel is supplied into the common rail 19 from an electronically controlled fuel pump 20 with variable discharge amount, and the fuel supplied into the common rail 20 is supplied to the fuel injection valve 3 through each fuel supply pipe 18.
On the other hand, in the embodiment shown in FIG. 1, the transmission 21 is connected to the output shaft of the engine, and the electric motor 23 is connected to the output shaft 22 of the transmission 21. In this case, in the embodiment shown in FIG. 1, a normal stepped automatic transmission having a torque converter is used as the transmission 21.
The electric motor 23 connected to the output shaft 22 of the transmission 21 constitutes an electric device that can generate a vehicle driving force separately from the vehicle driving force by the engine and can generate electric power by the engine. In the embodiment shown in FIG. 1, the electric motor 23 is mounted on a rotor 24 mounted on the output shaft 22 of the transmission 21 and a plurality of permanent magnets mounted on the outer peripheral surface, and an exciting coil for forming a rotating magnetic field. And an AC synchronous motor including the stator 25. The excitation coil of the stator 25 is connected to a motor drive control circuit 26, and this motor drive control circuit 26 is connected to a battery 27 that generates a DC high voltage.
The electronic control unit 30 is composed of a digital computer, and is connected to each other by a bidirectional bus 31. A ROM (read only memory) 32, a RAM (random access memory) 33, a CPU (microprocessor) 34, an input port 35 and an output port 36. It comprises. Output signals of the intake air amount detector 8 and the temperature sensor 14 are input to the input port 35 via the corresponding AD converters 37 respectively. In addition, various signals representing the gear position of the transmission 21 and the rotation speed of the output shaft 22 are input to the input port 35.
On the other hand, a load sensor 41 that generates an output voltage proportional to the depression amount L of the accelerator pedal 40 is connected to the accelerator pedal 40, and the output voltage of the load sensor 41 is input to the input port 35 via the corresponding AD converter 37. Is done. Further, a crank angle sensor 36 that generates an output pulse every time the crankshaft rotates, for example, 10 ° is connected to the input port 35. On the other hand, the output port 36 is connected to the fuel injection valve 3, the step motor for driving the throttle valve 10, the EGR control valve 16, the fuel pump 20, the transmission 21, and the motor drive control circuit 26 through corresponding drive circuits 38. .
When the supply of electric power to the exciting coil of the stator 25 of the electric motor 23 is stopped, the rotor 24 is idling. On the other hand, when the electric motor 23 is driven, the DC high voltage of the battery 27 is converted into a three-phase alternating current having a frequency fm and a current value Im in the motor drive control circuit 26, and this three-phase alternating current is supplied to the exciting coil of the stator 25. Is done. This frequency fm is a frequency necessary for rotating the rotating magnetic field generated by the exciting coil in synchronization with the rotation of the rotor 24, and this frequency fm is calculated by the CPU 34 based on the rotational speed of the output shaft 22. In the motor drive control circuit 26, the frequency fm is set as a three-phase AC frequency.
On the other hand, the output torque of the electric motor 23 is substantially proportional to the three-phase AC current value Im. The current value Im is calculated by the CPU 34 based on the required output torque of the electric motor 23, and the motor drive control circuit 26 sets the current value Im as a three-phase AC current value.
Further, when the electric motor 23 is driven by an external force, the electric motor 23 operates as a generator, and the electric power generated at this time is regenerated in the battery 27. Whether or not the electric motor 23 should be driven by an external force is determined according to the operating state of the engine. When it is determined that the electric motor 23 should be driven by an external force, the electric power generated in the electric motor 23 by the motor control circuit 26 Is regenerated by the battery 27.
First, the NO _X storage catalyst 13 shown in FIG. 1 will be described. A catalyst carrier made of alumina, for example, is supported on the base of the NO _X storage catalyst 13, and FIG. The cross section of is shown schematically. As shown in FIG. 2, a noble metal catalyst 46 is dispersedly supported on the surface of the catalyst carrier 45, and a layer of NO _X absorbent 47 is formed on the surface of the catalyst carrier 45.
In the embodiment according to the present invention, platinum Pt is used as the noble metal catalyst 46, and the constituents of the NO _X absorbent 47 are, for example, alkali metals such as potassium K, sodium Na, cesium Cs, barium Ba, calcium Ca. At least one selected from alkaline earths such as these, lanthanum La, and rare earths such as yttrium Y is used.
If the ratio of air and fuel (hydrocarbon) supplied into the exhaust passage upstream of the engine intake passage, the combustion chamber 2 and the NO _X storage catalyst 13 is referred to as the air-fuel ratio of the exhaust gas, the NO _X absorbent 47 air absorbs NO _X when the lean, the oxygen concentration in the exhaust gas performs the absorbing and releasing action of the NO _X that releases NO _X absorbed and reduced.
That is, the case where barium Ba is used as a component constituting the NO _X absorbent 47 will be described as an example. When the air-fuel ratio of the exhaust gas is lean, that is, when the oxygen concentration in the exhaust gas is high, it is contained in the exhaust gas. As shown in FIG. 2, NO is oxidized on platinum Pt 46 to become NO ₂ , and then absorbed into the NO _X absorbent 47 and combined with barium carbonate BaCO ₃ to absorb NO _{X in} the form of nitrate ions NO ₃ ^−. It diffuses into the agent 47. In this way, NO _X is absorbed in the NO _X absorbent 47. Exhaust oxygen concentration in the gas is NO ₂ with high long as the surface of the platinum Pt46 are generated, _the NO _X absorbent 47 of the NO _X absorbing capacity so long as NO ₂ not to saturate is absorbed in the NO _X absorbent 47 nitrate ions NO ₃ ^- are produced.
In contrast, NO _X storing catalyst 13 air-fuel ratio of the exhaust gas flowing into the reaction for the oxygen concentration in the exhaust gas is rich or the stoichiometric air-fuel ratio decreases the reverse (NO ₃ ^- → NO ₂₎ the process proceeds, _the NO _X absorbent in the 47 nitrate ions NO ₃ and thus ^- are released from _the NO _X absorbent 47 in the form of NO _2. Next, the released NO _X is reduced by unburned HC and CO contained in the exhaust gas.
Thus, when the air-fuel ratio of the exhaust gas is lean, that is, when combustion is performed under the lean air-fuel ratio, NO _X in the exhaust gas is absorbed into the NO _X absorbent 47. However becomes saturated is NO _X absorbing capacity of the NO _X absorbent 47 during the combustion of the fuel under a lean air-fuel ratio is continued, no longer able to absorb NO _X by _the NO _X absorbent 47 and thus End up. Therefore, in the embodiment according to the present invention, the exhaust gas is supplied by supplying additional fuel from the fuel injection valve 3 into the combustion chamber 2 before the absorption capacity of the NO _X absorbent 47 is saturated, for example, in the first half of the expansion stroke. of the air-fuel ratio temporarily rich and thereby so that to release NO _X from _the NO _X absorbent 47.
On the other hand, FIG. 3 the relationship between _the NO _X storage speed, i.e. _the amount of NO _X occluded per unit time in the NO _X storing catalyst 13 to _the NO _X storage amount and the NO _X storing catalyst 13, which is occluded in the NO _X storing catalyst 13 Is shown. FIG. 3 shows that the amount of NO _X that can be stored in the NO _X storage catalyst 13 per unit time increases as the NO _X storage amount decreases. Incidentally, in advance in the ROM32 in the form of a map as shown in FIG. 4 as a function of the discharge amount of NO _X NOXA the engine required torque TQ and the engine rotational speed N to be discharged per time unit from the combustion chamber 2 in the embodiment according to the present invention is stored, _the NO _X storage amount to _the NO _X storage catalyst 13 is estimated from the map.
In the embodiment according to the present invention, the vehicle is driven by the electric motor 23 as much as possible as long as the charge amount SOC of the battery 27 is sufficient. In this case, a lower limit value SC ₁ and the upper limit value SC ₂ is set in advance as shown in FIG. 5 (A) as a criterion for determining whether the state of charge SOC of the battery 27 is sufficient, these lower or to drive the vehicle is determined by the value SC ₁ and the upper limit value SC of whether the electric motor 23 for driving the vehicle by the engine based on _2.
In other words, the vehicle driving by the agency from the vehicle drive by an electric motor 23 is started the operation of the engine when the state of charge SOC have been performed driven by the electric motor 23 becomes lower than the lower limit value SC ₁ in the embodiment according to the present invention Switched. At this time, in order to charge the battery 27, the electric motor 23 is switched to generate power.
On the other hand, different driving methods in accordance with the vehicle driving force that is required when the state of charge SOC of the battery 27 exceeds the upper limit value SC ₂ is taken. That is, when the vehicle can be driven only by the electric motor 23 at this time, the operation of the engine is stopped and the driving of the vehicle by the electric motor 23 is started. On the other hand, when the vehicle cannot be driven only by the electric motor 23 at this time, the operation of the engine is continued, and the vehicle is driven by both the engine and the electric motor 23. At this time, the shortage of the vehicle driving force by the electric motor 23 is compensated by the engine.
The charge amount SOC is calculated by integrating the charge / discharge current I of the battery 27, for example. FIG. 5B shows an example of a charge amount calculation routine executed by interruption every fixed time. In this example, the charge / discharge current I of the battery 27 is added to the charge amount SOC every fixed time. This current value I is positive during charging and negative during discharging.
By the way, when the engine operation is stopped during the vehicle operation and then the engine operation is resumed, a large amount of NO _X is discharged from the combustion chamber 2 immediately after the engine operation is resumed as described above. In this case _the NO _X storage per unit time the NO _X storing catalyst 13 as can be seen from Figure 3 _the NO _X storage amount is large of the catalyst 13 becomes less _the amount of NO _X can be occluded, at this time was thus the NO _X storing catalyst 13 A large amount of NO _X will pass through. In this case the reducing amount of NO _X slip through the NO _X storing catalyst 13 is necessary to reduce the amount of NO _X stored in the NO _X storing catalyst 13 at the time of restarting operation of the engine.
Therefore, in the present invention, when the operation of the engine is stopped and the driving of the vehicle by the electric motor 23 is started, the NO _X storage amount stored in the NO _X storage catalyst 13 is larger than the predetermined storage amount. and so as to release the NO _X from the NO _X storing catalyst 13 and the air-fuel ratio of the exhaust gas flowing into the NO _X storing catalyst 13 rich. When NO _X is released from the NO _X storage catalyst 13 in this way, the NO _X storage amount in the NO _X storage catalyst 13 becomes zero when the engine is restarted, and thus is discharged from the combustion chamber 2 at this time. NO _X is favorably stored in the NO _X storage catalyst 13.
On the other hand, when the operation of the engine is stopped and driving of the vehicle by the electric motor 23 is started, the air-fuel ratio of the exhaust gas flowing into the NO _X storage catalyst 13 is made rich when the NO _X storage catalyst 13 is not activated. also the nO _X storing catalyst 13 is not satisfactorily nO _X is released from this time nO _X even released as being released nO _X is not well reduced.
Therefore, in the embodiment according to the present invention, the NO _X storage amount stored in the NO _X storage catalyst 13 when the operation of the engine is stopped and the driving of the vehicle by the electric motor 23 is started is based on the predetermined storage amount. perform the action of raising the temperature of the nO _X storing catalyst 13 when the number and the nO _X storing catalyst 13 also is not activated, the air-fuel ratio of the exhaust gas the nO _X storing catalyst 13 flows into the nO _X storing catalyst 13 after activation It is made rich to release NO _X from the NO _X storage catalyst 13.
Specifically, in the embodiment according to the present invention, the temperature of the NO _X storage catalyst 13 is detected by the temperature sensor 14, the NO _X storage amount is larger than a predetermined storage amount, and the NO _X storage catalyst 13 temperature the action of raising the temperature of _the NO _X storage catalyst 13 is performed when a predetermined lower than the activation temperature, the NO _X storing catalyst 13 after the temperature of the NO _X storing catalyst 13 has reached a predetermined activation temperature The air-fuel ratio of the exhaust gas flowing into the engine is made rich.
Next, the operation control routine will be described with reference to FIGS. This routine is executed by interruption every predetermined time.
Referring to FIG. 6, the discharge amount of NO _X NOXA is calculated from the map shown in FIG. 4, first, at step 50. Next, at step 51, this exhausted NO _X amount is added to the NO _X storage amount ΣNOX stored in the NO _X storage catalyst 13. Next, at step 52, it is judged if the EV travel flag indicating that the vehicle should be traveled by only the electric motor 23 or by both the electric motor 23 and the engine is set. When the EV traveling flag is not set, the routine proceeds to step 53.
Charge SOC of step 53 the battery 27 whether exceeds the upper limit value SC ₂ is discriminated. The vehicle is driven only by the engine proceeds to step 54 when the SOC ≦ SC _2. At this time, the electric motor 23 generates a power. Then the air-fuel ratio of the exhaust gas flowing into the NO _X storing catalyst 13 by the rich to release NO _X from the NO _X storing catalyst 13 when exceeding the allowable value _the NO _X storage amount ΣNOX step 55 is predetermined A NO _X release process is performed. If NO _X emission process is performed ΣNOX is set to zero.
On the other hand, it is set EV travel flag proceeds to step 56 when the state of charge SOC is determined to exceed the upper limit value SC ₂ in step 53, then the routine proceeds to step 57. When the EV running flag is set, the process jumps from step 52 to step 57 in the next processing cycle. In step 57 the state of charge SOC is determined whether it is lower than the lower limit value SC ₁ is when SOC ≧ SC ₁ jumps to step 59. In contrast, EV traveling flag proceeds to step 58 becomes a SOC <SC ₁ is reset, then the routine proceeds to step 59. When the EV running flag is reset, the routine proceeds from step 52 to step 54 through step 53. Therefore the process proceeds to step 59 after a SOC> SC _2, it until SOC <SC _1.
In step 59, it is determined whether or not the vehicle can be driven only by the electric motor 23 from the required vehicle driving force, that is, whether or not the vehicle can be driven only by the electric motor 23. When traveling with only the electric motor 23 is not possible, the routine proceeds to step 60 where the vehicle is driven by the electric motor 23 and the engine. At this time, the shortage of the vehicle driving force by the electric motor 23 is compensated by the output of the engine. Then the air-fuel ratio of the exhaust gas flowing into the NO _X storing catalyst 13 by the rich to release NO _X from the NO _X storing catalyst 13 when exceeding the allowable value _the NO _X storage amount ΣNOX step 61 is predetermined A NO _X release process is performed.
On the other hand, when it is judged that the vehicle can travel only by the electric motor 23 in step 59 whether less than occluded amount NX of _the NO _X storage amount ΣNOX proceeds to step 62 is predetermined or not. The storage amount NX is an amount _the NO _X storage speed is very high a fairly small amount, as shown in FIG. Accordingly, when the NO storage amount ΣNOX is smaller than the storage amount NX, it is not necessary to release NO _X from the NO _X storage catalyst 13, so at this time the routine proceeds to step 63 where the engine is stopped and then the routine proceeds to step 67 to proceed to the electric motor 23. Only traveling is performed. At this time, the transmission 21 is in a neutral state.
Thus, in the embodiment according to the present invention, the NO _X storage amount ΣNOX stored in the NO _X storage catalyst 13 when the operation of the engine is stopped and the driving of the vehicle by the electric motor 23 is started is determined in advance. When the stored amount is smaller than the storage amount NX, the driving of the vehicle by the electric motor 23 is started without making the air-fuel ratio of the exhaust gas flowing into the NO _X storage catalyst 13 rich.
On the other hand, when it is determined in step 62 that the NO _X storage amount ΣNOX is larger than the storage amount NX, the routine proceeds to step 64, where it is determined whether or not the temperature TC of the NO _X storage catalyst 13 is lower than the activation temperature T _0. The When TC ≧ T ₀ , that is, when the NO _X storage catalyst 13 is activated, the routine proceeds to step 65 where the engine is stopped, and in step 66, NO _X release processing is performed when the engine stops. For example a certain period immediately before the engine is stopped, the fuel injection valve 3 toward the combustion chamber 2 is supplied additional fuel in the first half late expansion stroke, the air-fuel ratio of the exhaust gas thereby flowing into the NO _X storing catalyst 13 Is made rich. In this case, the exhaust gas having a rich air-fuel ratio flows slowly through the NO _X storage catalyst 13, so that the NO _X release and reduction actions are performed satisfactorily. Next, the routine proceeds to step 67 where the running of the vehicle by the electric motor 23 is started.
On the other hand, when it is determined in step 64 that the temperature TC of the NO _X storage catalyst 13 is lower than the activation temperature T ₀ , the routine proceeds to step 68 where temperature increase control of the NO _X storage catalyst 13 is performed. At this time, the temperature increase control of the NO _X storage catalyst 13 is performed, for example, by increasing the engine output and increasing the exhaust gas temperature. At this time, the electric motor 23 is used as a generator, and the increase in engine output is consumed by the power generation action of the electric motor 23.
Next, when the NO _X storage catalyst 13 is activated, the routine proceeds from step 64 to step 65, where the engine is stopped, and in step 66, NO _X release processing is performed. The NO _X storage amount ΣNOX continues to increase while the temperature increase control of the NO _X storage catalyst 13 is performed, and when the NO _X release process is performed, the increased stored NO _X can be reduced. The amount of additional fuel supplied into the combustion chamber 2 is increased. Next, the routine proceeds to step 67 where traveling by the electric motor 23 is started.
Next, another embodiment of the electric device will be described with reference to FIG.
Referring to FIG. 8, in this embodiment, the electric device includes a pair of

motor generators

70 and 71 that operate as an electric motor and a generator, and a planetary gear mechanism 72. The planetary gear mechanism 72 includes a sun gear 73, a ring gear 74, a planetary gear 75 disposed between the sun gear 73 and the ring gear 74, and a planetary carrier 76 that carries the planetary gear 75. The sun gear 73 is connected to the rotation shaft 77 of the motor generator 71, and the planetary carrier 76 is connected to the output shaft 78 of the engine 1.
The ring gear 74 is connected to a rotating shaft 79 of the motor generator 70 on the one hand, and connected to an output shaft 80 connected to a driving wheel on the other hand via a belt 81. Therefore, it can be seen that when the ring gear 74 rotates, the output shaft 80 is rotated accordingly.
Although a detailed description of the operation of the electric device is omitted, generally speaking, the motor generator 70 mainly operates as an electric motor, the motor generator 71 mainly operates as a generator, and the operation of the engine 1 is performed. And the vehicle can be driven by the motor generator 70. That is, when the motor generator 70 is rotated, the ring gear 74 is rotated, and the rotational force of the ring gear 74 is transmitted to the output shaft 80 via the belt 81, thereby driving the vehicle. On the other hand, since the planetary carrier 76 does not rotate at this time, when the ring gear 74 rotates, the sun gear 73 is rotated, and at this time, the motor generator 71 rotates idly.
On the other hand, when the vehicle is driven by the motor generator 70 and the vehicle driving force at this time is assisted by the output of the engine 1, the rotational force of the planetary carrier 76 is added to the rotational force of the ring gear 74. Further, when the vehicle is driven by the engine 1 and power is generated by the motor generator 71, the motor generator 70 idles.

2 ... Combustion chamber 4 ... Intake manifold 5 ... Exhaust manifold 13 ... NO _X storage catalyst 21 ... Transmission 23 ... Electric motor 27 ... Battery

Claims

Exhaust of a hybrid vehicle having an electric device capable of generating vehicle driving force separately from the vehicle driving force by the engine and capable of generating electric power by the engine, and capable of driving the vehicle by one or both of the engine and the electric device NO in purifier, into the engine exhaust passage, the air-fuel ratio of the inflowing exhaust gas when the lean occluding the air-fuel ratio of the exhaust gas occluding NO X contained in the exhaust gas flowing becomes the stoichiometric air-fuel ratio or rich occlusion that arranged the NO X storing catalyst to release the X, is the NO X storage amount stored in the NO X storage catalyst when to stop the operation of the engine starts to drive the vehicle by the electric device is predetermined hybrid vehicle when greater than the amount which is adapted to release NO X from the NO X storing catalyst and the air-fuel ratio of the exhaust gas flowing into the NO X storage catalyst rich Exhaust gas purification device of.
It flows into the NO X storage catalyst when smaller than storage amount the NO X storage amount being occluded is predetermined in the NO X storage catalyst when to stop the operation of the engine starts to drive the vehicle by the electric device The exhaust emission control device for a hybrid vehicle according to claim 1, wherein driving of the vehicle by the electric device is started without making the air-fuel ratio of the exhaust gas rich.
Stop operation of the engine the NO X storage catalyst and more than storage amount the NO X storage amount being occluded is predetermined in the NO X storage catalyst at the start of the driving of the vehicle by the electric device is activated perform the action of raising the temperature of the nO X storage catalyst when not, so that the nO X storage catalyst to release nO X fuel ratio from the nO X storage catalyst in the rich exhaust gas flowing into the nO X storage catalyst after activation The exhaust emission control device for a hybrid vehicle according to claim 1.
The temperature raising action of the NO X storage catalyst is performed by increasing the engine output and raising the exhaust gas temperature, and at this time, the increase in the engine output is consumed by the power generation action by the electric device. An exhaust emission control device for a hybrid vehicle as described.
A vehicle is provided that supplies electric power for driving the vehicle to the electric device and is charged by electric power generated by the electric device, and the vehicle is driven only by the electric device when the charge amount of the battery exceeds a predetermined upper limit value. The exhaust emission control device for a hybrid vehicle according to claim 1, wherein when the vehicle can be driven, the operation of the engine is stopped and the drive of the vehicle by the power generation device is started.