JP2006037817A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine capable of efficiently creating reformed gas with appropriate supply quantity of fuel while performing lean operation. <P>SOLUTION: This internal combustion engine is provided with at lease one first combustion pattern cylinder 1a-1c performing first combustion pattern, at lease one second combustion pattern cylinder 1d performing second combustion pattern, an exhaust gas route 3 provided with an exhaust manifold 3A collecting exhaust gas from the first and the second combustion pattern cylinders 1a-1d and an exhaust gas passage 3B discharging exhaust gas to outside via the exhaust manifold 3A, an exhaust gas branch flow route 13 branching at least part of exhaust gas from the second combustion pattern cylinder 1d out of a branch passage 3A4 of the exhaust manifold 3A, a reformer 12 arranged on the exhaust gas route 3 and communicating to the exhaust gas branch route 13 and creating reformed gas from exhaust gas and fuel, a reformed gas introduction route 14 introducing reformed gas to the intake air route 2, and a control device 4 performing lean combustion in the first combustion pattern cylinders 1a-1c and rich combustion in the second combustion pattern cylinder 1d. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an internal combustion engine capable of supplying a reformed gas generated from exhaust gas and fuel added to the exhaust gas to an intake passage.

  Conventionally, fuel is added to exhaust gas, and this is reformed by a reforming catalyst supported on a reformer to generate reformed gas. An internal combustion engine is known in which this reformed gas is supplied to an intake passage and burned in a combustion chamber together with an air-fuel mixture. For example, this type of internal combustion engine is disclosed in Patent Documents 1 and 2 below.

JP-A-6-264732 JP 2004-92520 A

  By the way, in order to take out the reformed gas (hydrogen gas) by adding fuel to the exhaust gas and performing a reforming reaction (steam reforming or dehydrogenation reaction (decomposition reaction)) with a reformer, the exhaust gas The excess air ratio λ of the gas is preferably λ ≦ 1, and if λ> 1, a large amount of fuel must be added, which is not preferable.

  That is, if the stoichiometry (hereinafter referred to as “stoichi”) or the rich exhaust gas in which the excess air ratio λ becomes λ ≦ 1, all of the added fuel can be used for the reforming reaction. In the case of lean exhaust gas satisfying λ> 1, since oxygen remains in the exhaust gas, a fuel and a desired fuel for making the reformer oxygen-free by performing an oxidation reaction with the oxygen This requires a fuel for generating a quantity of reformed gas (hydrogen gas), and it is necessary to add extra fuel.

  For this reason, in an internal combustion engine that performs lean combustion at a lean air-fuel ratio, excess fuel must be added to the exhaust gas to generate reformed gas, thereby reducing the fuel consumption rate. The advantage of the lean burn is greatly impaired.

  Therefore, the object of the present invention is to provide an internal combustion engine that improves the disadvantages of the conventional example and can generate reformed gas with an appropriate amount of fuel supply while performing lean operation.

  In order to achieve the above object, according to the first aspect of the present invention, at least one first combustion pattern cylinder that performs combustion in the first combustion pattern, and at least one second combustion pattern cylinder that performs combustion in the second combustion pattern; An exhaust path having an exhaust manifold for collecting the exhaust gases discharged from the first and second combustion pattern cylinders, an exhaust passage for exhausting the exhaust gas to the outside through the exhaust manifold, and a second thereof An exhaust gas diversion path for diverting at least a part of the exhaust gas discharged from the combustion pattern cylinder from the diversion passage of the exhaust manifold; and an exhaust gas diversion path disposed on the exhaust path and in communication with the exhaust gas diversion path. A reformer for generating a reformed gas from the fuel and fuel, a reformed gas introduction path for introducing the reformed gas generated by the reformer into an intake path, and While for lean burn one combustion pattern cylinder, and a control device for rich combustion to the second combustion pattern cylinder.

  According to the first aspect of the present invention, rich exhaust gas is introduced into the reformer, and reformed gas is generated from the exhaust gas and unburned fuel in the exhaust gas. Further, the lean operation can be performed while generating the reformed gas.

  In order to achieve the above object, according to a second aspect of the present invention, in the internal combustion engine of the first aspect, the shunt passage of the exhaust manifold through which the exhaust gas from the first combustion pattern cylinder flows and the second When the reforming gas is generated in the control device, a flow path opening / closing means capable of changing between a communicating state and a closed state is provided for the branch passage of the exhaust manifold through which the exhaust gas from the combustion pattern cylinder flows. A function of operating the flow path opening / closing means is provided so as to narrow or close the flow path between the respective diversion paths.

  According to the internal combustion engine of the second aspect, since the rich exhaust gas is reliably introduced into the reformer, the reformed gas can be generated efficiently.

  Since the internal combustion engine which concerns on this invention can produce | generate reformed gas efficiently in a reformer, performing lean operation, it can improve a fuel consumption rate.

  Embodiments of an internal combustion engine according to the present invention will be described below in detail with reference to the drawings. The present invention is not limited to the embodiments.

  Example 1 of an internal combustion engine according to the present invention will be described.

  First, the configuration of the internal combustion engine in the first embodiment will be described in detail with reference to FIG.

  The internal combustion engine of the first embodiment includes an internal combustion engine main body 1, an intake passage 2 for introducing air into the first to fourth cylinders 1a to 1d in the internal combustion engine main body 1, and the first to fourth cylinders 1a. The exhaust path 3 for exhausting the exhaust gas discharged from ˜1d to the outside, and an electronic control unit (hereinafter referred to as “ECU”) 4 for performing combustion control are provided.

  First, the intake passage 2 includes an intake passage 2A for introducing air from the outside, and an intake manifold 2B for diverting the air in the intake passage 2A to the first to fourth cylinders 1a to 1d.

  In the intake passage 2A, an air flow meter 5 for measuring the intake air amount, a throttle valve 6 for adjusting the inflow amount of air into the first to fourth cylinders 1a to 1d, and a throttle for operating the throttle valve 6 A valve actuator 6a is provided. Here, the measurement signal of the air flow meter 5 is output to the ECU 4, and the ECU 4 calculates the intake air amount and the load based on the intake air amount. Further, the throttle valve actuator 6a is controlled by the ECU 4.

  Each branch passage in the intake manifold 2B communicates with each intake port (not shown) from the first to fourth cylinders 1a to 1d formed in the internal combustion engine body 1, and each of them is connected to the intake manifold 2B. The intake port is provided with first to fourth fuel injection devices 9 a to 9 d for injecting fuel in the fuel tank 8 pumped by the fuel pump 7. Here, in these first to fourth fuel injection devices 9a to 9d, the injection amount of each fuel is controlled by the ECU 4. In FIG. 1, for convenience of illustration, first to fourth fuel injection devices 9 a to 9 d are provided in the respective branch passages of the intake manifold 2 </ b> B.

Subsequently, the exhaust path 3, eventually one flow passage exhaust gas discharged from each first through the fourth branch flow path 3A ₁ to 3 A ₄ from the first to fourth cylinders 1a~1d A so-called 4-1 type exhaust manifold 3A and an exhaust passage 3B for discharging the collected exhaust gas to the outside.

  Here, in the first embodiment, an A / F sensor 10 is provided in the exhaust passage 3B, and an output signal of the A / F sensor 10 is output from the first to fourth cylinders 1a to 1d by the ECU 4. Used for air-fuel ratio control.

  Further, the exhaust passage 3B is provided with a catalyst device 11 and a reformer 12 carrying a reforming catalyst (for example, a rhodium-based one). In the first embodiment, the reformer 12 is arranged on the upstream side of the catalyst device 11 in the exhaust passage 3B as shown in FIG.

  The reformer 12 of the first embodiment is provided with a cylinder 12a that allows exhaust gas to flow in from the exhaust manifold 3A side and discharge it to the downstream catalytic device 11 side, and is provided in the cylinder 12a for reforming inside. A reforming chamber 12b carrying a catalyst is provided, and reformed gas is generated from exhaust gas and fuel in the reforming chamber 12b. For this reason, it is necessary to introduce exhaust gas and fuel into the reforming chamber 12b.

  Here, the ECU 4 of the first embodiment performs combustion control of the internal combustion engine as described above. In this combustion control, there is control of the air-fuel ratio of the air-fuel mixture flowing into the first to fourth cylinders 1a to 1d, and the internal combustion engine body 1 burns in various combustion patterns by this air-fuel ratio control. . Typical combustion patterns include stoichiometric combustion with an air-fuel mixture having a stoichiometric air-fuel ratio (A / F≈14.7), and a mixture with an air-fuel ratio that is leaner than the stoichiometric air-fuel ratio (for example, A / F ≧ 20). There are lean combustion by air and rich combustion by air-fuel mixture having an air-fuel ratio (for example, A / F ≦ 12) that is richer than the stoichiometric air-fuel ratio.

  The exhaust gas after combustion according to each combustion pattern has an excess air ratio λ = 1 in stoichiometric combustion, an excess air ratio λ> 1 in lean combustion, and an excess air ratio λ <1 in rich combustion. . That is, exhaust gas in which neither oxygen component nor fuel component remains is exhausted in stoichiometric combustion, exhaust gas in which oxygen component remains is discharged in lean combustion, and unburned fuel component remains in rich combustion. Exhaust gas is discharged.

  Therefore, in the first embodiment, the ECU 4 causes the internal combustion engine body 1 to perform rich combustion, and guides the rich exhaust gas after the combustion to the reforming chamber 12b, thereby reforming the exhaust gas and unburned fuel. It introduce | transduces in the chamber 12b and produces | generates reformed gas.

In the first embodiment, divert all or part of the exhaust gas flowing through the at least any one of the first to the fourth branch flow path 3A ₁ to 3 A ₄ in the exhaust manifold 3A, this It is configured to lead to the reforming chamber 12b.

  By the way, it is not preferable from the viewpoint of fuel consumption rate to perform rich combustion of all of the first to fourth cylinders 1a to 1d when generating the reformed gas. For this reason, in the first embodiment, when the reformed gas is generated, the ECU 4 is provided with a control function so that the first to third cylinders 1a to 1c are lean burned and the fourth cylinder 1d is richly burned. That is, in the first embodiment, when the reformed gas is generated, combustion is performed in two types of combustion patterns in one internal combustion engine body 1, and the first to third cylinders 1a to 1c are performed. Is the first combustion pattern cylinder that performs the first combustion pattern (here, lean combustion), and the fourth cylinder 1d is the second combustion pattern cylinder that performs the second combustion pattern (here, rich combustion).

Then, along with this, in the first embodiment, so that leads the fourth shunt rich exhaust gas from the passage 3A ₄ exhaust manifold 3A to the reforming chamber 12b, the fourth branch flow path 3A ₄ the intermediate portion and the reforming chamber communicated with the inlet side of 12b, the exhaust gas diversion passage (exhaust gas diversion pathway) in which a part of exhaust gas flowing through the fourth branch flow path 3A ₄ is shunted 13 provided.

  Here, when the reforming catalyst supported in the reforming chamber 12b becomes lower than a predetermined activation temperature (for example, 600 ° C.), the reforming reaction becomes dull, and a desired amount of reformed gas (hydrogen gas) is generated. Can not do it.

  Therefore, the reforming chamber 12b of the first embodiment is composed of a plurality of rooms communicating with each other, each of which carries a reforming catalyst, and each chamber is provided with a predetermined interval in the cylindrical body 12a. By disposing, an exhaust passage 12c through which exhaust gas from the exhaust passage 3B flows is formed between the outer wall surfaces of the rooms.

  That is, the reformer 12 of the first embodiment uses the heat of the high temperature exhaust gas (in other words, heat exchange with the heat of the high temperature exhaust gas) to increase the temperature of the reforming catalyst. Thus, the reforming reaction is activated.

  In the first embodiment, the reformed gas introduction path for introducing the reformed gas generated by the reformer 12 into the first to fourth cylinders 1a to 1d is provided. As the reformed gas introduction path of the first embodiment, there is provided a reformed gas introduction path 14 for communicating between the outlet side of the reforming chamber 12b and the downstream side of the throttle valve 6 in the intake path 2A.

  The reformed gas introduction passage 14 is provided with a flow rate adjusting valve 15 for adjusting the amount of reformed gas introduced into the intake passage 2A, and a valve actuator 15a for operating the flow rate adjusting valve 15. The valve actuator 15a is operation-controlled by the ECU 4.

  Here, the reformed gas discharged from the reformer 12 or the exhaust gas that has not undergone the reforming reaction is in a high temperature state, and when these are introduced into the intake passage 2A as they are, the air sucked from the outside warms. As a result, the charging efficiency into the first to fourth cylinders 1a to 1d deteriorates.

  Therefore, a cooling device 16 is provided in the reformed gas introduction passage 14 as shown in FIG. 1, thereby cooling the reformed gas and exhaust gas discharged from the reformer 12. For example, the cooling device 16 may be not only ON / OFF controlled by the ECU 4 but also the temperature of the cooling device 16 can be appropriately varied by the ECU 4.

  Hereinafter, the operation of the internal combustion engine configured as described above will be described.

  The ECU 4 according to the first embodiment controls the throttle valve actuator 6a, the first to fourth fuel injection devices 9a to 9d, and the valve actuator 15a so as to flow the air-fuel mixture that flows into the first to fourth cylinders 1a to 1d. Set the air / fuel ratio.

  In this case, the ECU 4 uses the fuel of the first to third fuel injection devices 9a to 9c so that the air-fuel mixture to the first to third cylinders 1a to 1c becomes a lean air-fuel ratio (for example, A / F ≧ 20). Adjust the injection amount. On the other hand, the ECU 4 adjusts the fuel injection amount of the fourth fuel injection device 9d so that the air-fuel mixture flowing into the fourth cylinder 1d has a rich air-fuel ratio (for example, A / F ≦ 12). Further, since this internal combustion engine is a port injection type internal combustion engine, the ECU 4 injects fuel from the first to fourth fuel injection devices 9a to 9d at the time of valve overlap.

  Thereby, lean combustion is performed in the first to third cylinders 1a to 1c, and rich combustion is performed in the fourth cylinder 1d.

Here, since the exhaust gas diversion passage 13 is provided in the fourth diversion passage 3A ₄ of the exhaust manifold 3A, a part of the rich exhaust gas flowing through the fourth diversion passage 3A ₄ is provided. It flows into the exhaust gas branch passage 13.

On the other hand, the lean exhaust gas in the first to third branch passages 3A _{1 to} 3A ₃ and the remaining rich exhaust gas in the fourth branch passage 3A ₄ gather in the exhaust passage 3B, and then the reformer 12 Flows into the exhaust passage 12c and is discharged to the catalyst device 11 side.

  For this reason, the reforming catalyst in the reforming chamber 12b is heated by the exhaust gas flowing through the exhaust passage 12c and becomes the activation temperature or higher. As a result, an endothermic reaction occurs in the rich exhaust gas (exhaust gas and unburned fuel) flowing into the reforming chamber 12b to generate reformed gas.

For example, when the exhaust gas is “7.6 CO ₂ +6.8 H ₂ O + 40.8 N ₂ ” and the unburned gasoline fuel is “C _7.6 H _13.6 ”, the endothermic reaction is
1.56 (7.6 CO ₂ +6.8 H ₂ O + 40.8 N ₂ ) +3 (C _7.6 H _13.6 ) +984.8 Kcal → 31 H ₂ +34.7 CO + 63.6 N ₂
It is represented by

  That is, according to the endothermic reaction in this case, 31 mol of hydrogen gas and 34.7 mol of carbon monoxide gas are generated from 3 mol of the unburned gasoline fuel.

  The reformed gas generated in the reformer 12 is introduced into the intake passage 2A from the reformed gas introduction passage 14 together with the remaining exhaust gas, and the intake air from the outside and the first to fourth fuel injection devices 9a to 9a. It flows into the first to fourth cylinders 1a to 1d and burns together with the air-fuel mixture consisting of 9d spray fuel.

  In the internal combustion engine of the first embodiment, various effects can be achieved by introducing the reformed gas and the exhaust gas into the first to fourth cylinders 1a to 1d and burning them.

  That is, introduction of exhaust gas into the first to fourth cylinders 1a to 1d reduces pump loss and cooling loss, and further increases the specific heat ratio, so that torque can be improved and fuel consumption rate can be reduced. Become.

  On the other hand, the introduction of the exhaust gas increases the combustion fluctuation due to the decrease in the combustion temperature and the combustion speed, thereby deteriorating the fuel consumption rate, and the first to third cylinders 1a to 1c and the fourth cylinder 1d. Torque fluctuations may occur between the two. However, since the reformed gas (especially hydrogen gas) is introduced together with the exhaust gas in the first embodiment, the calorific value at the time of combustion increases and rapid combustion becomes possible. The lean limit can be expanded. As a result, the deterioration of the fuel consumption rate is improved and the torque fluctuation can be reduced.

  By the way, if the exhaust gas in the exhaust gas branch passage 13 is a lean combustion gas in an oxygen atmosphere, the added fuel is combusted by oxygen in the exhaust gas, and the reformed gas is produced by the remaining fuel after the combustion. Is generated.

  However, according to the internal combustion engine of the first embodiment, the fourth cylinder 1d is richly burned so that the exhaust gas in the exhaust gas diversion passage 13 is made into rich combustion gas that does not become an oxygen atmosphere. Any unburned fuel in the gas can be used to produce reformed gas. For this reason, the internal combustion engine does not need to supply fuel to the exhaust gas diversion passage 13 separately in order to generate the reformed gas, so that the fuel consumption rate can be reduced.

  The internal combustion engine performs lean combustion in the first to third cylinders 1a to 1c, while performing rich combustion in the fourth cylinder 1d. Here, as described above, the lean limit of the first to third cylinders 1a to 1c is expanded by introducing the reformed gas and the exhaust gas, so that the fuel consumption rate is reduced and unburned such as hot NOx and HC. Gas can be reduced effectively.

  Thus, according to the internal combustion engine of the first embodiment, the reformer 12 can efficiently generate the reformed gas while performing the lean operation, so that the fuel consumption rate can be improved.

  In the internal combustion engine of the first embodiment described above, only the fourth cylinder 1d is richly burned, but rich combustion may be carried out also in other cylinders. However, as described above, in order to improve the fuel consumption rate, it is preferable to perform rich combustion only in a small number of cylinders as in the first embodiment.

  Here, the exhaust gas purification action in the internal combustion engine of the first embodiment will be exemplified.

  As described above, in the internal combustion engine of the first embodiment, when the reformed gas is generated, lean combustion is performed in the first to third cylinders 1a to 1c, and rich combustion is performed in the fourth cylinder 1d. For this reason, depending on the air-fuel ratio of each of the first to fourth cylinders 1a to 1d, the exhaust gas flowing through the exhaust passage 3B has three modes: stoichiometric, lean, and rich.

  Therefore, the catalyst device 11 carries a three-way catalyst, an adsorption reduction type NOx catalyst, and an oxidation catalyst. When the stoichiometric exhaust gas flows into the exhaust passage 3B, the exhaust gas is purified by the three-way catalyst, when the lean exhaust gas flows, it is purified by the adsorption reduction type NOx catalyst, and when the rich exhaust gas flows, it is purified by the oxidation catalyst.

  For example, three independent flow paths (not shown) are provided in the catalyst device 11, and each of them supports a three-way catalyst, an adsorption reduction type NOx catalyst, and an oxidation catalyst. Then, an opening / closing valve (not shown) is provided on the upstream side of each flow path, and the ECU 4 is caused to open / close the opening / closing valve in accordance with the excess air ratio λ of the exhaust gas flowing through the exhaust passage 3B. That is, the ECU 4 obtains the excess air ratio λ from the output signal of the A / F sensor 10 provided in the exhaust passage 3B, determines whether the exhaust gas flowing through the exhaust passage 3B is stoichiometric, lean, or rich, Purification is performed by opening an on-off valve of a flow path on which a catalyst corresponding to the exhaust gas is supported.

  Next, a second embodiment of the internal combustion engine according to the present invention will be described.

  The internal combustion engine of the second embodiment is different from the internal combustion engine of the first embodiment described above in that the following configuration is added, and other configurations and operations are the same as those of the first embodiment.

Here, in the internal combustion engine of the first embodiment described above, a part of the rich exhaust gas flowing through the fourth branch passage 3A ₄ of the exhaust manifold 3A flows into the exhaust gas branch passage 13, and the rest is the exhaust passage. Flows into 3B.

  However, when the remaining rich exhaust gas flows into the exhaust passage 3B, the pressure of the exhaust gas in the exhaust gas diversion passage 13 decreases, and the amount of the exhaust gas flowing into the reforming chamber 12b decreases. There is a concern about a decrease in the amount of the reformed gas generated introduced into the first to fourth cylinders 1a to 1d.

On the other hand, the lean exhaust gas discharged from the first to third cylinders 1a to 1c flows into the exhaust passage 3B through the first to third branch passages 3A _{1 to} 3A ₃ , but a part of the lean exhaust gas flows. also conceivable that it would flow into the fourth diversion passage 3A ₄ by the pressure difference between the rich exhaust gas of the fourth diversion passage 3A _4. If such an event occurs, an air-fuel mixture of rich and lean exhaust gas flows into the reforming chamber 12b to cause an oxidation reaction (combustion), which reduces the amount of reformed gas produced, which is not preferable.

Therefore, in the internal combustion engine of the second embodiment, the flow path opening / closing that can change the flow path at the boundary between the third branch flow path 3A ₃ and the fourth flow branch path 3A ₄ between the communication state and the closed state. Means are provided to eliminate the above disadvantages.

  As the flow path opening / closing means of the second embodiment, as shown in FIG. 2, a flow path opening / closing valve 17 provided with a valve capable of steplessly changing the flow path at the boundary portion from a communication state to a closed state, A valve actuator 17a for operating the road opening / closing valve 17 is provided. The valve actuator 17a is operation-controlled by the ECU 4.

For example, when the exhaust gas pressure drop in the exhaust gas branch passage 13 is observed, the ECU 4 controls the valve actuator 17 a to throttle or close the flow path opening / closing valve 17. As a result, the pressure in the fourth branch passage 3A ₄ rises, and all the rich exhaust gas flowing through the fourth branch passage 3A ₄ flows into the exhaust gas branch passage 13. Therefore, the rich exhaust gas surely flows into the reforming chamber 12b and the reformed gas is generated. On the other hand, the generated reformed gas is surely pumped from the first to the fourth cylinders 1a to 1d as the pressure increases.

  In this case, the ECU 4 can determine the pressure drop of the exhaust gas in the exhaust gas diversion passage 13 from the introduction amount of the reformed gas and the remaining exhaust gas to the first to fourth cylinders 1a to 1d. Specifically, if the air-fuel ratio of the exhaust gas obtained from the output signal of the A / F sensor 10 is larger than the air-fuel ratio of the entire air-fuel mixture flowing into the first to fourth cylinders 1a to 1d, It can be determined that the introduction amount of the reformed gas and the remaining exhaust gas into the first to fourth cylinders 1a to 1d has decreased, and it can be determined that the pressure of the exhaust gas in the exhaust gas diversion passage 13 has decreased. Therefore, the ECU 4 compares the air-fuel ratio of the entire air-fuel mixture into the first to fourth cylinders 1a to 1d and the air-fuel ratio of the exhaust gas by the A / F sensor 10 to determine the pressure drop of the exhaust gas.

In addition, even when lean exhaust gas flows into the fourth branch passage 3A4, the ECU ₄ controls the valve actuator 17a to throttle or close the flow path opening / closing valve 17. Thereby, since only rich exhaust gas is introduced into the reforming chamber 12b, the reformed gas can be generated without waste.

In such a case, the ECU 4 compares the air-fuel ratio of the air-fuel mixture to the first to third cylinders 1a to 1c with the air-fuel ratio of the exhaust gas obtained from the output signal of the A / F sensor 10, thereby making the lean exhaust gas. The inflow of gas into the fourth branch passage 3A ₄ can be determined. Specifically, when the lean exhaust gas flows into the fourth branch passage 3A ₄ , the air-fuel ratio of the exhaust gas by the A / F sensor 10 is the air-fuel mixture from the first to the third cylinders 1a to 1c. since the air-fuel ratio the same as the, thereby flowing into the fourth diversion passage 3A ₄ lean exhaust gas can be determined. Therefore, the ECU 4 compares the air-fuel ratio of the air-fuel mixture to the first to third cylinders 1a to 1c and the air-fuel ratio of the exhaust gas by the A / F sensor 10, and the fourth branch passage 3A _{4 for} lean exhaust gas. Let the inflow to

  Here, the ECU 4 may be configured to uniformly throttle or close the flow path opening / closing valve 17 when generating the reformed gas.

  Thus, according to the internal combustion engine of the second embodiment, the reformed gas can be efficiently generated by the opening / closing operation of the flow path opening / closing valve 17.

  By the way, depending on the internal combustion engine, a supercharger may be provided. In such an internal combustion engine with a supercharger, the engine output can be reduced by reducing the exhaust pressure. However, in the second embodiment, since only one cylinder is throttled by the flow path opening / closing valve 17, the exhaust pressure is not greatly reduced, and the engine output is not affected.

  Here, in each of the first and second embodiments described above, since the port injection type internal combustion engine is illustrated, the ECU 4 injects fuel from the first to fourth fuel injection devices 9a to 9d at the time of valve overlap. . However, when the reformed gas is generated as described above in the direct injection type internal combustion engine, the ECU 4 is configured to inject fuel from the first to fourth fuel injection devices 9a to 9d in the exhaust stroke. To do.

  Further, in each of the first and second embodiments described above, the internal combustion engine body 1 having four cylinders is illustrated, but the present invention is not necessarily limited thereto.

  In each of the first and second embodiments, the reformer 12 is disposed on the upstream side of the catalyst device 11 in the exhaust passage 3B. However, the reformer 12 is disposed on the downstream side of the catalyst device 11. May be. However, in order to efficiently raise the temperature of the reforming catalyst by the exhaust gas in the exhaust passage 3B, it is preferable to arrange the reforming catalyst upstream of the catalyst device 11 where the exhaust gas is at a higher temperature.

  As described above, the internal combustion engine according to the present invention is useful as a technique that can efficiently generate reformed gas while performing lean operation, and is particularly suitable for improving the fuel consumption rate.

1 is a diagram illustrating a configuration of a first embodiment of an internal combustion engine according to the present invention. It is a figure which shows the structure of Example 2 of the internal combustion engine which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine main body 1a 1st cylinder 1b 2nd cylinder 1c 3rd cylinder 1d 4th cylinder 2 Intake path 2A Intake path 2B Intake manifold 3 Exhaust path 3A Exhaust manifold 3A ₁ 1st shunt path 3A ₂ 2nd shunt path 3A ₃ 3rd branch passage 3A ₄ 4th branch passage 3B Exhaust passage 4 ECU (control device)
6 throttle valve 6a throttle valve actuator 9a first fuel injection device 9b second fuel injection device 9c third fuel injection device 9d fourth fuel injection device 10 A / F sensor 11 catalyst device 12 reformer 12a cylinder 12b reforming chamber 12c Exhaust passage 13 Exhaust gas diversion passage (exhaust gas diversion passage)
14 Reformed gas introduction passage (reformed gas introduction route)
DESCRIPTION OF SYMBOLS 15 Flow control valve 15a Valve actuator 16 Cooling device 17 Flow path on-off valve 17a Valve actuator

Claims (2)

At least one first combustion pattern cylinder that performs combustion in a first combustion pattern;
At least one second combustion pattern cylinder that performs combustion in a second combustion pattern;
An exhaust path comprising an exhaust manifold for collecting the exhaust gases discharged from the first and second combustion pattern cylinders and an exhaust passage for exhausting the exhaust gas to the outside through the exhaust manifold;
An exhaust gas diversion path for diverting at least a part of the exhaust gas discharged from the second combustion pattern cylinder from the diversion path of the exhaust manifold;
A reformer that is disposed on the exhaust path and communicates with the exhaust gas diversion path to generate a reformed gas from the exhaust gas and fuel;
A reformed gas introduction path for introducing the reformed gas generated by the reformer into an intake path;
A control device that causes the first combustion pattern cylinder to perform lean combustion while the second combustion pattern cylinder performs rich combustion;
An internal combustion engine comprising: The shunt passage of the exhaust manifold through which the exhaust gas from the first combustion pattern cylinder flows and the shunt passage of the exhaust manifold through which the exhaust gas from the second combustion pattern cylinder flows are communicated and closed. Provide variable channel opening and closing means,
2. The control device is provided with a function of operating the flow path opening / closing means so as to restrict or close a flow path between the respective diversion passages when generating reformed gas. The internal combustion engine described.

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