JP2006029296A - Control device and control method for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine capable of improving durability. <P>SOLUTION: This control device for the internal combustion engine is provided with an exhaust gas introducing passage 33 for introducing exhaust gas on an exhaust path 30 of the internal combustion engine 1-1 to a fuel reforming device 31; a fuel adding device 55 for adding fuel to exhaust gas introduced to the fuel reforming device 31; the fuel reforming device 31 for reforming added fuel; a reformed fuel introducing passage 34 for introducing exhaust gas including reformed fuel to an intake path 30 of the internal combustion engine 1-1; and a flow regulating valve 36 for regulating amount of exhaust gas including reformed fuel to be introduced to the intake path 20 of the internal combustion engine 1-1. The control device for the internal combustion engine determines a fuel cut condition of the internal combustion engine 1-1, and closes the flow regulating valve 36 when determining that the internal combustion engine 1-1 is in the fuel cut condition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control device and a control method for an internal combustion engine, and more particularly, to a control device and a control method for an internal combustion engine that introduces exhaust gas and fuel that has been added and reformed into the exhaust gas into an intake path of the internal combustion engine. .

In general, in an internal combustion engine such as a gasoline engine mounted on a passenger car or a truck, a part of exhaust gas in an exhaust path is used to improve fuel efficiency by reducing pump loss and reduce NO _x by lowering fuel temperature. Is introduced into the intake path. On the other hand, a fuel reformer is provided to improve fuel consumption by reducing the combustion speed or lean combustion, and to reduce knocking. The fuel reformer reforms the fuel, and hydrogen (H ₂ ) is converted from the fuel. There is an internal combustion engine that produces carbon monoxide (CO) and the like, and introduces the produced hydrogen into an intake passage. Here, as shown in Patent Document 1, a technique combining these is proposed. In this conventional internal combustion engine, fuel is added when a part of the exhaust gas in the exhaust path is introduced into the fuel reformer, and the added fuel is reformed by a reforming catalyst provided in the fuel reformer. Then, the reformed fuel and exhaust gas are introduced into the intake passage.

JP-A-6-264732

  By the way, a driver of a vehicle equipped with an internal combustion engine may decelerate the vehicle by an engine brake generated by releasing his / her foot from an accelerator pedal. This engine brake stops the supply of fuel to the internal combustion engine when the driver removes his or her foot from the accelerator pedal, that is, the fuel is cut, the internal combustion engine is rotated by the drive wheels, and the throttle valve is closed. This is mainly caused by the pump loss obtained.

  However, in the above-described conventional internal combustion engine, when the vehicle is decelerated due to fuel cut, even if the throttle valve is closed, exhaust gas containing fuel reformed according to the opening of the flow rate adjustment valve is introduced into the intake path. The Therefore, the pump loss obtained by closing the throttle valve is changed, so that there is a problem that the advantage of the engine brake is changed. In other words, the vehicle deceleration desired by the driver cannot be obtained by the engine brake, and the vehicle deceleration required according to the traveling state of the vehicle cannot be obtained by the engine brake.

  The present invention has been made in view of the above, and an object of the present invention is to provide a control device and a control method for an internal combustion engine that can suppress at least a change in the dominantness of an engine brake.

In order to solve the above-described problems and achieve the object, according to the present invention, an exhaust gas introduction passage for introducing exhaust gas in an exhaust path of an internal combustion engine into the fuel reformer and the fuel reformer are introduced. Fuel addition means for adding fuel to the exhaust gas, a fuel reformer for reforming the added fuel,
The reformed fuel introduction passage for introducing the exhaust gas containing the reformed fuel into the intake path of the internal combustion engine, and the amount of the exhaust gas containing the reformed fuel introduced into the intake path of the internal combustion engine are adjusted. A control device for an internal combustion engine, further comprising a fuel cut determination means for determining a fuel cut state of the internal combustion engine, and when determining that the internal combustion engine is in a fuel cut state, the flow rate adjustment The valve is closed.

  Further, in the present invention, the fuel added to the exhaust gas in the exhaust path of the internal combustion engine introduced into the fuel reformer by the fuel reformer is reformed, and the exhaust gas containing the reformed fuel is changed. In the control method of the internal combustion engine introduced into the intake path of the internal combustion engine, the fuel flow determination procedure for determining the fuel cut state of the internal combustion engine, and the flow rate adjustment when determining that the internal combustion engine is in the fuel cut state And a procedure for closing the valve.

  According to these inventions, the fuel cut state of the internal combustion engine is determined by the fuel cut determination means, so that the vehicle on which the internal combustion engine is mounted is decelerated by the engine brake generated when the throttle valve is closed. In the fuel cut state of the internal combustion engine, that is, when the vehicle is decelerated, the flow rate adjustment valve is closed. Therefore, when the vehicle is decelerated due to the fuel cut of the internal combustion engine, the throttle valve and the flow rate adjustment valve are closed, and the exhaust gas containing the reformed fuel is introduced into the intake path of the internal combustion engine. Absent. Thereby, since the pump loss obtained by closing the throttle valve does not change depending on the opening degree of the flow rate adjusting valve, it is possible to suppress the change of the engine brake, particularly the deterioration of the advantage.

  In the present invention, the control device for an internal combustion engine further includes a backflow prevention valve between the exhaust path of the internal combustion engine and the exhaust gas introduction passage, and it is determined that the internal combustion engine is in a fuel cut state. Closes the flow rate adjustment valve and the backflow prevention valve.

  According to this invention, when the internal combustion engine is in a fuel cut state, that is, when the vehicle is decelerated, not only the flow rate adjustment valve but also the backflow prevention valve is closed. Therefore, when the vehicle is decelerated due to the fuel cut of the internal combustion engine, the throttle valve, the flow rate adjustment valve, and the backflow prevention valve are closed, and the reformed fuel is contained by the pulsation generated in the exhaust path of the internal combustion engine. It is possible to prevent the exhaust gas to be discharged and the exhaust gas to which fuel is added from flowing out into the exhaust path.

  According to the present invention, the control device for an internal combustion engine further includes hydrogen concentration detection means for detecting a hydrogen concentration contained in the exhaust gas containing the reformed fuel, and the internal combustion engine is returned from the fuel cut state. When it is determined that it is time, the flow rate adjustment valve and the backflow prevention valve are opened when the detected hydrogen concentration is equal to or higher than a predetermined concentration.

  According to this invention, when the hydrogen concentration H with respect to the exhaust gas containing the reformed fuel is not less than the predetermined concentration H1, that is, when the exhaust gas containing the reformed fuel contains sufficient hydrogen, Open the check valve. Therefore, when the internal combustion engine returns from the fuel cut state and the exhaust gas containing the reformed fuel is introduced into the intake passage of the internal combustion engine, the amount of hydrogen contained in the exhaust gas containing the reformed fuel is small. The knocking etc. which generate | occur | produce can be suppressed.

  In the present invention, the control device for an internal combustion engine further includes reformer temperature detection means for detecting the temperature of the fuel reformer, wherein the detected hydrogen concentration is less than a predetermined concentration, and the detection When the temperature of the formed fuel reformer is equal to or higher than a predetermined temperature, the fuel adding means adds fuel to the exhaust gas introduced into the fuel reformer.

  According to the present invention, when the temperature of the fuel reformer becomes equal to or higher than the predetermined temperature 1, the reforming catalyst provided in the fuel reformer is activated. Accordingly, since the exhaust gas added with fuel is introduced into the fuel reformer in which the reforming catalyst is activated, hydrogen can be generated from the fuel added to the exhaust gas by the reforming catalyst.

  In the present invention, in the control device for an internal combustion engine, when it is determined that the internal combustion engine is returning from a fuel cut state, after the air-fuel ratio of the internal combustion engine has stabilized, The check valve is opened.

  According to the present invention, after the internal combustion engine returns from the fuel cut state and the air-fuel ratio of the internal combustion engine is stabilized, the flow rate adjustment valve and the backflow prevention valve are opened, and the exhaust gas containing the reformed fuel is removed from the internal combustion engine. Introduced into the engine intake path. Therefore, even if the flow regulating valve is opened and the exhaust gas containing the reformed fuel is introduced into the internal combustion engine together with the fuel, the air / fuel ratio of the internal combustion engine can be set to a desired air / fuel ratio in a short time. As a result, it is possible to prevent the emission from deteriorating when the internal combustion engine returns from the fuel cut state and the flow rate adjustment valve opens.

  According to the present invention, in the control device for an internal combustion engine, a hydrogen concentration detection means for detecting a hydrogen concentration contained in the exhaust gas containing the reformed fuel, and the internal combustion engine based on the detected hydrogen concentration Hydrogen amount calculating means for calculating the amount of hydrogen introduced into the intake passage of the engine, wherein the hydrogen amount calculating means detects the hydrogen amount when the flow rate adjusting valve and the check valve are closed. Calculating based on the hydrogen concentration, and correcting the fuel supply amount of the fuel supplied to the internal combustion engine when the flow rate adjusting valve and the check valve are opened based on the calculated hydrogen amount To do.

  According to the present invention, when the internal combustion engine returns from the fuel cut state and opens the flow rate adjustment valve and the backflow prevention valve, the correction is made based on the amount of hydrogen contained in the exhaust gas containing the reformed fuel. The amount of fuel supplied is supplied to the internal combustion engine. Therefore, even if the flow rate adjusting valve is opened and the exhaust gas containing the reformed fuel is introduced into the internal combustion engine together with the fuel, it is possible to prevent the air / fuel ratio of the internal combustion engine from greatly deviating from the stoichiometric air / fuel ratio. . Thereby, when the internal combustion engine returns from the fuel cut state and the flow rate adjustment valve opens, it is possible to further suppress the deterioration of the emission.

  In the present invention, the exhaust gas introduction passage for introducing the exhaust gas into the fuel reformer, the fuel adding means for adding fuel to the exhaust gas introduced into the fuel reformer, and the added fuel are modified. A reforming fuel introduced into the intake path of the internal combustion engine, and a reformed fuel introduced into the intake path of the internal combustion engine A control device for an internal combustion engine comprising: a flow rate adjusting valve that adjusts an amount of exhaust gas including: an actual deceleration detecting means for detecting an actual deceleration during deceleration of a vehicle on which the internal combustion engine is mounted; and the internal combustion engine And a required deceleration calculating means for calculating a required deceleration required when the vehicle on which the engine is mounted is decelerated, wherein the flow rate adjusting valve is configured to detect the detected actual deceleration and the calculated required deceleration. And the modified based on the difference between And adjusting the amount of exhaust gas containing fuel.

  Further, in the present invention, the fuel added to the exhaust gas in the exhaust path of the internal combustion engine introduced into the fuel reformer by the fuel reformer is reformed, and the exhaust gas containing the reformed fuel is changed. In the control method of the internal combustion engine introduced into the intake path of the internal combustion engine, an actual deceleration detection procedure for detecting an actual deceleration at the time of deceleration of the vehicle on which the internal combustion engine is mounted, and a vehicle on which the internal combustion engine is mounted Based on the difference between the detected actual deceleration and the calculated requested deceleration, a modification introduced into the intake path of the internal combustion engine based on the requested deceleration calculating procedure for calculating the requested deceleration required at the time of deceleration. And adjusting the amount of exhaust gas containing the refined fuel by the flow rate adjusting valve.

  According to these inventions, the opening degree of the flow rate adjustment valve is adjusted based on the difference between the actual deceleration and the required deceleration when the vehicle on which the internal combustion engine is mounted is decelerated. In other words, the flow rate is adjusted so that the actual deceleration of the vehicle due to the engine brake generated by the pump loss obtained by closing the throttle valve while the flow rate adjustment valve is open is the same as the required deceleration. Adjust the opening of the valve. Therefore, it is possible to suppress a change in the engine brake dominant with respect to the required deceleration required when the vehicle is decelerated.

  The control device and control method for an internal combustion engine according to the present invention includes a flow rate adjustment valve that is closed in a fuel cut state of the internal combustion engine or based on a difference between an actual deceleration and a required deceleration when the vehicle is decelerated. By adjusting, it is possible to suppress the change in the engine brake dominant.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by the following Example. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

  First, a control device and a control method for an internal combustion engine according to a first embodiment will be described. FIG. 1 is a diagram illustrating a configuration example of the internal combustion engine according to the first embodiment. As shown in FIG. 1, the internal combustion engine 1-1 according to the first embodiment includes an internal combustion engine body 10 such as a gasoline engine, an intake path 20, an exhaust path including a fuel reformer 31 and a flow rate adjustment valve 36. 30 and an ECU (Engine Control Unit) 40 that controls the flow rate adjustment valve opening degree of the flow rate adjustment valve 36.

  An intake passage 20 is connected to the internal combustion engine body 10, and air and fuel are introduced into each cylinder 11 of the internal combustion engine body 10 from the outside through the intake passage 20. Further, an exhaust path 30 is connected to the internal combustion engine body 10, and exhaust gas exhausted from each cylinder 11 of the internal combustion engine body 10 is exhausted to the outside through the exhaust path 30.

  The intake passage 20 includes an air cleaner 21, an intake passage 22, an air flow meter 23, and a throttle valve 24. The air from which the dust has been removed by the air cleaner 21 is introduced into each cylinder 11 of the internal combustion engine body 10 via the intake passage 22. The air flow meter 23 detects the amount of intake air introduced into the internal combustion engine body 10, that is, the intake air, and outputs it to the ECU 40 described later. The throttle valve 24 is driven by an actuator (not shown) to adjust the amount of intake air taken into each cylinder 11 of the internal combustion engine body 10. The control of the opening degree of the throttle valve 24, that is, the valve opening degree control is performed by the ECU 40 described later.

  A fuel injection valve 51 that supplies fuel to the internal combustion engine 10 is provided in the intake passage 22 of the intake passage 20. The fuel stored in the fuel tank 52 is pumped to the fuel injection valve 51 through the fuel passage 54 when the fuel pump 53 is driven. Control of the fuel injection amount and injection timing of the fuel injection valve 51, that is, injection control is performed by the ECU 40 described later.

  The exhaust passage 30 includes a fuel reformer 31, an exhaust passage 32, an exhaust gas introduction passage 33, a reformed fuel introduction passage 34, a reformed fuel cooling device 35, and a flow rate adjustment valve 36. . The fuel reformer 31 is formed in a cylindrical shape, and a fuel reforming passage 31b is disposed in the hollow portion 31a. The hollow portion 31 a communicates with the exhaust passage 32 at both ends thereof. The exhaust gas exhausted from the internal combustion engine body 10 passes through the fuel reformer 31 by passing through the hollow portion 31a. The exhaust gas that has passed through the hollow portion 31a is introduced into a purification device (not shown) via the exhaust passage 32, and after the harmful substances are purified by the purification device, the exhaust gas is exhausted to the outside. The exhaust passage 32 upstream of the fuel reformer 31 is provided with an A / F sensor 37 that detects an air-fuel ratio based on the exhaust gas exhausted into the exhaust passage 32 and outputs the detected air-fuel ratio to the ECU 40 described later. ing.

The fuel reforming passage 31b is configured by communicating a number of pipes (not shown). Each of the pipes does not communicate with the hollow portion 31a, and the exhaust gas in the fuel reforming passage 31b does not flow out to the hollow portion 31a. A reforming catalyst 31c is provided in the fuel reforming passage 31b. The reforming catalyst 31c is a rhodium-based catalyst and reforms fuel added to exhaust gas described later. Specifically, the reforming catalyst 31c generates hydrogen (H ₂ ), carbon monoxide (CO), and the like from the fuel by an endothermic reaction that is a reforming reaction. Specific endothermic reaction is, for example,
1.56 (7.6CO ₂ + 6.8H ₂ O + 40.8N ₂ ) + 3C _7.6 H _12.6 + 984.8Kcal → 31H ₂ + 34.7CO + 63.6N ₂
It becomes.

  The fuel reforming passage 31b is provided with a reforming catalyst temperature sensor 31d which is a reformer temperature detecting means for detecting the temperature of the reforming catalyst 31c and outputting the detected temperature to the ECU 40 described later. Further, one end of the fuel reforming passage 31 b communicates with the exhaust gas introduction passage 33, and the other end communicates with the reformed fuel introduction passage 34. Here, the exhaust gas introduction passage 33 is provided with a fuel addition device 55 as fuel addition means for adding fuel to the exhaust gas introduced into the fuel reformer 31. Similarly to the fuel injection valve 51, the fuel adding device 55 is driven by the fuel pump 53, so that the fuel stored in the fuel tank 52 is pumped through the fuel passage 54 and the branch passage 56. . Control of the fuel addition amount and addition timing of the fuel addition device 55, that is, addition control is performed by the ECU 40 described later.

The fuel reforming passage 31b introduces exhaust gas exhausted from the internal combustion engine body 10 to which fuel is added by the fuel addition device 55. The exhaust gas to which the introduced fuel is added is reformed by the reforming catalyst 31c, and becomes an exhaust gas containing hydrogen (H ₂ ) and carbon monoxide (CO), that is, an exhaust gas containing the reformed fuel. Then, it flows out into the reformed fuel introduction passage 34.

  The reformed fuel introduction passage 34 is provided with a reformed fuel cooling device 35 and a flow rate adjustment valve 36, and communicates with the intake passage 22 on the downstream side of the throttle valve 24 in the intake passage 20. The reformed fuel cooling device 35 cools the exhaust gas containing the reformed fuel at a high temperature (for example, about 700 ° C.) flowing into the reformed fuel introduction passage 34 from the fuel reforming passage 31b. By cooling the exhaust gas, it is possible to suppress a reduction in volumetric efficiency when the exhaust gas is introduced into each cylinder 11 of the internal combustion engine body 10 together with air and fuel, and fuel efficiency can be improved. . The flow rate adjustment valve 36 introduces an exhaust gas recirculation amount, which is an amount for introducing the exhaust gas containing the reformed fuel into the intake passage 20 of the internal combustion engine 1-1, that is, again introducing the exhaust gas into each cylinder 11 of the internal combustion engine body 10. To be adjusted. The control of the flow rate adjustment valve opening of the flow rate adjustment valve 36, that is, the flow rate adjustment valve opening degree control is performed by the ECU 40 described later.

  The ECU 40 is a control device for the internal combustion engine 1 and controls the operation of the internal combustion engine 1. The ECU 40 receives various input signals from sensors attached to various parts of a vehicle (not shown) on which the internal combustion engine 1 is mounted. Specifically, the engine speed detected by an angle sensor attached to a crankshaft (not shown) of the internal combustion engine body 10, the intake air amount detected by the air flow meter 23, and the accelerator opening detected by the accelerator pedal sensor 60. The oxygen concentration of the exhaust gas detected by the A / F sensor 37, the temperature T of the fuel reformer 31 detected by the reforming catalyst temperature sensor 31d, and the like. The ECU 40 outputs various output signals based on these input signals and various maps stored in the storage unit 43. Specifically, a valve opening signal for performing valve opening control of the throttle valve 24, an injection signal for performing injection control of the fuel injection valve 51, an ignition signal for performing ignition control of an ignition plug (not shown) of the internal combustion engine body 10, There are output signals such as a flow adjustment valve opening signal for controlling the flow adjustment valve opening of the flow adjustment valve 36 and an addition signal for performing addition control of the fuel addition device 55.

  Here, the fuel injection amount supplied from the fuel injection valve 51 to the internal combustion engine 1 is that the internal combustion engine 1-1 is operated with stoichiometry (λ = 1) based on the engine speed and the intake air amount among these input signals. That is, the air-fuel ratio is calculated so as to be the stoichiometric air-fuel ratio. The fuel injection amount may be calculated based on the input signal and the fuel injection amount map stored in the storage unit 43, or the air-fuel ratio detected by the input signal and the A / F sensor 37. You may calculate based on these. Further, the exhaust gas recirculation amount of the exhaust gas including the reformed fuel introduced into the intake path 20 of the internal combustion engine 1-1 by the flow rate adjusting valve 36 is determined by the engine speed and the intake air amount among these input signals. It is calculated based on the exhaust gas recirculation amount map stored in the storage unit 43. The amount of fuel added to the exhaust gas introduced into the exhaust gas introduction passage 33 from the fuel addition device 55 is the temperature T of the fuel reformer 31 detected by the reforming catalyst temperature sensor 31d among these input signals. And the calculated exhaust gas recirculation amount. Specifically, the amount of fuel added is determined based on the temperature of the fuel reformer 31 and the exhaust gas recirculation amount calculated above. The concentration is determined so that the fuel can be most efficiently reformed by the catalyst 31c. In addition, when adding fuel to exhaust gas, it is preferable to supply the fuel injection amount from the fuel injection valve 51 to the internal combustion engine 1 by subtracting the fuel addition amount from the calculated fuel injection amount. Thereby, when the exhaust gas containing the reformed fuel is introduced again into each cylinder 11 of the internal combustion engine body 10, it is possible to suppress the operation of the internal combustion engine 1 with the air-fuel ratio being rich. The exhaust gas recirculation amount may be corrected according to the amount of fuel reformed by the reforming catalyst 31c, particularly the concentration of produced hydrogen with respect to the exhaust gas.

  Specifically, the ECU 40 includes an input / output port (I / O) 41 for inputting / outputting the input signal and the output signal, a processing unit 42, various fuel injection amount maps, exhaust gas recirculation amount maps, and the like. The storage unit 43 stores a map and the like. The processing unit 42 includes a memory and a CPU (Central Processing Unit), and loads a program based on a control method for the internal combustion engine 1-1, which will be described later, into the memory and executes the program, thereby controlling the internal combustion engine 1-1. Etc. may be realized. The storage unit 43 is a non-volatile memory such as a flash memory, a volatile memory such as a ROM (Read Only Memory) or a volatile memory such as a RAM (Random Access Memory) that can be read and written. The memory can be configured by a combination of these. Moreover, in this invention, although the control method of the internal combustion engine 1-1 is implement | achieved by ECU40, it is not limited to this, You may implement | achieve this ECU40 with the control apparatus formed separately.

  Next, the operation of the ECU 40 that is the control device for the internal combustion engine 1-1 according to the first embodiment will be described. FIG. 2 is a diagram showing an operation flow of the control device for the internal combustion engine according to the present invention. First, as shown in the figure, the processing unit 42 of the ECU 40 determines whether or not the internal combustion engine 1-1 is in a fuel cut state (step ST101). That is, it is determined whether or not the supply of fuel to the internal combustion engine body 10 by the fuel injected from the fuel injection valve 51 is stopped. Specifically, for example, whether or not the driver has lifted his / her foot from an accelerator pedal (not shown) is determined based on whether or not the accelerator opening detected by the accelerator pedal sensor 60 input to the ECU 40 is 0 or almost 0. To do. If processing unit 42 determines that internal combustion engine 1-1 is not in the fuel cut state, step ST101 is repeated.

  Next, when determining that the internal combustion engine 1-1 is in the fuel cut state, the processing unit 42 of the ECU 40 closes the flow rate adjustment valve 36 (step ST102). Specifically, the processing unit 42 outputs the flow rate adjustment valve opening signal to the flow rate adjustment valve 36 via the input / output port 41 or stops outputting the flow rate adjustment valve opening signal, thereby adjusting the flow rate adjustment. The valve 36 is closed so that the reformed fuel introduction passage 34 and the intake passage 22 do not communicate with each other.

  At this time, when the processing unit 42 outputs the injection signal to the fuel injection valve 51 and the addition signal to the fuel addition device 55, the processing unit 42 stops the output. That is, by not performing the injection control of the fuel injection valve 51 and the addition control of the fuel addition device 55, the supply of fuel to the internal combustion engine 1-1 and the addition of fuel to the exhaust gas are stopped. Further, the processing unit 42 closes the throttle valve 24 by outputting a valve opening signal to the throttle valve 24 or stopping the output of the valve opening signal via the input / output port 41, thereby The upstream intake passage 22 and the downstream intake passage 24 are prevented from communicating with each other.

  Here, as described above, since the internal combustion engine 1-1 is in the fuel cut state and the throttle valve 24 is closed, an engine brake is generated in the internal combustion engine 1-1, and this internal combustion engine 1-1. The vehicle on which is mounted is in a deceleration state. At this time, since the flow rate adjusting valve 36 is closed, even if the intake passage 22 on the downstream side of the throttle valve 24 with which the reformed fuel introduction passage 34 communicates becomes negative pressure, this reformed fuel introduction is performed. The exhaust gas containing the reformed fuel in the passage 34 is not introduced into the intake passage 20 of the internal combustion engine 1-1, that is, the intake passage 22 on the downstream side of the throttle valve 24. That is, when the vehicle is decelerated due to the fuel cut of the internal combustion engine 1-1, the exhaust gas containing the reformed fuel is not introduced into the intake path 20 of the internal combustion engine 1-1. Thereby, since the pump loss obtained by closing the throttle valve 24 does not change depending on the opening degree of the flow rate adjustment valve 36, it is possible to suppress the change of the engine brake, particularly the deterioration of the advantage. Therefore, the driver can obtain the desired vehicle deceleration by the engine brake when he / she releases his / her foot from an accelerator pedal (not shown).

Further, when the internal combustion engine 1-1 is in the fuel cut state, the flow rate adjustment valve 36 is closed, so that the exhaust gas containing the reformed fuel is brought into the atmosphere via the internal combustion engine body 10 and the exhaust path 30. Exhaust is suppressed. That is, when the internal combustion engine 1-1 is in the fuel cut state, harmful substances such as carbon monoxide (CO) generated by the reforming catalyst 31 c from the fuel added to the exhaust gas are generated in each cylinder of the internal combustion engine body 10. 11 is suppressed from being released to the atmosphere without being combusted, so that deterioration of emissions can be suppressed. Further, when the internal combustion engine 1-1 is in the fuel cut state, harmful substances such as hydrogen (H ₂ ) generated by the reforming catalyst 31c from the fuel added to the exhaust gas are caused by the cylinders 11 of the internal combustion engine body 10. Therefore, it is possible to suppress a reduction in fuel consumption because it is suppressed from being released to the atmosphere without being burned.

  Next, the processing unit 42 of the ECU 40 determines whether or not the condition for the internal combustion engine 1-1 to return from the fuel cut state is satisfied (step ST103). Specifically, it is determined whether or not the supply of fuel to the internal combustion engine main body 10 by the fuel injected from the fuel injection valve 51 is started. Specifically, for example, it is determined based on the accelerator opening detected by the accelerator pedal sensor 60 input to the ECU 40 whether or not an accelerator pedal (not shown) is depressed by the driver. If processing unit 42 determines that internal combustion engine 1-1 does not satisfy the condition for returning from the fuel cut state, it repeats steps ST101 to ST103.

  Next, when the internal combustion engine 1-1 satisfies the condition for returning from the fuel cut state, the processing unit 42 of the ECU 40 opens the flow rate adjustment valve 36 (step ST104). Specifically, the processing unit 42 starts the flow rate adjustment valve control of the flow rate adjustment valve 36 by outputting a flow rate adjustment valve opening signal to the flow rate adjustment valve 36 via the input / output port 41. At this time, the processing unit 42 outputs the injection signal to the fuel injection valve 51 and the addition signal to the fuel addition device 55, respectively, and starts the injection control of the fuel injection valve 51 and the addition control of the fuel addition device 55. Further, the processing unit 42 outputs a valve opening signal to the throttle valve 24 via the input / output port 41, and starts the valve opening control of the throttle valve 24.

Note that the fuel added to the exhaust gas introduced into the fuel reforming passage 31b undergoes an endothermic reaction by the reforming catalyst 31c, and hydrogen (H ₂ ), carbon monoxide (CO), and the like are generated. The exhaust gas containing hydrogen (H ₂ ) and carbon monoxide (CO), that is, the exhaust gas containing the reformed fuel is cooled by the reformed fuel cooling device 35, and the flow rate adjustment valve control is started. The exhaust gas recirculation amount is adjusted by the valve 36 and flows into the intake passage 22 of the intake passage 20. The exhaust gas containing the reformed fuel that has flowed out into the intake passage 22 is introduced into each cylinder 11 of the internal combustion engine body 10 together with the air and the fuel injected by the fuel injection valve 51. At this time, since hydrogen is contained in addition to the fuel, the combustion speed and the amount of heat generated during combustion are improved by ignition of a spark plug (not shown). As a result, the internal combustion engine 1-1 according to the first embodiment can increase torque, improve fuel efficiency, and reduce knocking. Further, since exhaust gas is included in addition to air and fuel, the combustion temperature at the time of combustion can be lowered by igniting a spark plug (not shown), and pump loss can be reduced. Thus, the internal combustion engine 1-1 according to the first embodiment, it is possible to further improve the reduction and fuel efficiency of a harmful substance contained in exhaust gas NO _x.

  Next, a control device and a control method for an internal combustion engine according to a second embodiment will be described. FIG. 3 is a diagram illustrating a configuration example of the internal combustion engine according to the second embodiment. The internal combustion engine 1-2 shown in the figure is different from the internal combustion engine 1-1 shown in FIG. 1 in that a hydrogen concentration detection sensor 38 and a backflow prevention valve 39 are provided. Note that the basic configuration of the internal combustion engine 1-2 shown in FIG. 3 is the same as the basic configuration of the internal combustion engine 1-2 shown in FIG.

  The hydrogen concentration detection sensor is a hydrogen concentration detection means that detects the hydrogen concentration H contained in the exhaust gas containing the reformed fuel in the reformed fuel introduction passage 34 and outputs it to the ECU 40. Further, the backflow prevention valve 39 is provided between the exhaust passage 32 and the exhaust gas introduction passage 33 by being driven by an actuator (not shown), and is connected to the exhaust passage 32 and the exhaust gas introduction passage 33 by opening and closing. , Do not communicate. Control of opening / closing of the backflow prevention valve 39, that is, backflow prevention valve opening / closing control is performed by the ECU 40.

  Next, the operation of the ECU 40 that is the control device for the internal combustion engine 1-2 according to the second embodiment will be described. FIG. 4 is a diagram illustrating an operation flow of the control device for the internal combustion engine according to the second embodiment. In addition, the operation | movement same as operation | movement of the control apparatus of the internal combustion engine 1-1 concerning Example 1 shown in FIG. 2 is demonstrated easily.

  First, as shown in the figure, the processing unit 42 of the ECU 40 determines whether or not the internal combustion engine 1-2 is in a fuel cut state (step ST201). If processing unit 42 determines that internal combustion engine 1-2 is not in the fuel cut state, processing unit 42 repeats step ST201.

  Next, when determining that the internal combustion engine 1-2 is in the fuel cut state, the processing unit 42 of the ECU 40 closes the flow rate adjustment valve 36 and the backflow prevention valve (step ST202). Specifically, the processing unit 42 outputs the flow rate adjustment valve opening signal to the flow rate adjustment valve 36 via the input / output port 41 or stops outputting the flow rate adjustment valve opening signal, thereby adjusting the flow rate adjustment. The valve 36 is closed so that the reformed fuel introduction passage 34 and the intake passage 22 do not communicate with each other. Further, the processing unit 42 closes the backflow prevention valve 39 by outputting a backflow prevention valve opening / closing signal to the backflow prevention 39 or stopping outputting the backflow prevention valve opening / closing signal via the input / output port 41. The exhaust passage 32 and the exhaust gas introduction passage 33 are prevented from communicating with each other.

  At this time, the processing unit 42 stops the supply of fuel to the internal combustion engine 1-2 and the addition of fuel to the exhaust gas by not performing the injection control of the fuel injection valve 51 and the addition control of the fuel addition device 55. The throttle valve 24 is closed so that the upstream intake passage 22 and the downstream intake passage of the throttle valve 24 do not communicate with each other.

  Here, as described above, since the internal combustion engine 1-2 is in the fuel cut state and the throttle valve 24 is closed, the dominant of the engine brake is changed, particularly the dominant, as in the first embodiment. It can suppress becoming worse. Therefore, the driver can obtain the desired vehicle deceleration by the engine brake when he / she releases his / her foot from an accelerator pedal (not shown).

  When the internal combustion engine 1-2 is in the fuel cut state, the internal combustion engine body 10 is rotated by the drive wheels, and pulsation is generated in the exhaust passage of the exhaust passage 30 of the internal combustion engine 1-2. Therefore, when the backflow prevention valve 39 is not closed, the pulsation generated in the exhaust passage 32 causes reformation in the reformed fuel introduction passage 34 and the fuel reforming passage 31b of the fuel reformer 31. The exhaust gas containing fuel and the exhaust gas to which the fuel in the fuel reforming passage 31b and the exhaust gas introduction passage 33 is added flow out to the exhaust passage 30, that is, the exhaust passage 32. However, the ECU 40, which is the control device for the internal combustion engine 1-2 according to the second embodiment, closes not only the flow rate adjustment valve 36 but also the backflow prevention valve 39 when the internal combustion engine 1-2 is in a fuel cut state, that is, when the vehicle is decelerated. I speak. Therefore, when the vehicle is decelerated due to the fuel cut of the internal combustion engine 1-2, the throttle valve 24, the flow rate adjustment valve 36, and the backflow prevention valve 39 are closed and reformed by the pulsation generated in the exhaust passage 32. The exhaust gas containing the fuel and the exhaust gas to which the fuel is added can be prevented from flowing out into the exhaust passage 32.

As a result, when the internal combustion engine 1-2 is in the fuel cut state, harmful substances such as carbon monoxide (CO) generated by the reforming catalyst 31c from the fuel added to the exhaust gas are removed from the internal combustion engine body 10. Since the release to the atmosphere without being burned by the cylinder 11 is further suppressed as compared with the case where only the flow rate adjustment valve 36 is closed, the deterioration of the mission can be further suppressed. Further, when the internal combustion engine 1-2 is in the fuel cut state, harmful substances such as hydrogen (H ₂ ) generated by the reforming catalyst 31c from the fuel added to the exhaust gas are caused to the cylinders 11 of the internal combustion engine body 10. As a result, the reduction in fuel consumption can be further suppressed as compared with the case where only the flow rate adjustment valve 36 is closed. Further, when the internal combustion engine 1-2 is in the fuel cut state, by closing the check valve 39, the low-temperature air flowing into the exhaust passage 32 of the exhaust passage 30 from the outside into the fuel reforming passage 31b. Since it is not introduced, a decrease in the temperature T of the fuel reformer 31 can be suppressed, and the fuel reforming efficiency of the fuel added to the exhaust gas when the internal combustion engine 1-2 returns from the fuel cut state can be reduced. Can be suppressed.

  Next, the processing unit 42 of the ECU 40 determines whether or not the condition for the internal combustion engine 1-2 to return from the fuel cut state is satisfied (step ST203). If processing unit 42 determines that internal combustion engine 1-2 does not satisfy the condition for returning from the fuel cut state, it repeats steps ST201 to ST203.

  Next, when the internal combustion engine 1-2 satisfies the condition for returning from the fuel cut state, the processing unit 42 of the ECU 40 acquires the hydrogen concentration H in the reformed fuel introduction passage 34 (step ST204). That is, the hydrogen concentration H contained in the exhaust gas containing the reformed fuel in the reformed fuel introduction passage 34 detected by the hydrogen concentration detection sensor 38 which is a hydrogen concentration detecting means is acquired. At this time, the processing unit 42 outputs an injection signal to the fuel injection valve 51 and starts injection control of the fuel injection valve 51. Further, the processing unit 42 outputs a valve opening signal to the throttle valve 24 via the input / output port 41, and starts the valve opening control of the throttle valve 24.

  Next, the processing unit 42 of the ECU 40 determines whether or not the acquired hydrogen concentration H is equal to or higher than a predetermined concentration H1 stored in the storage unit 43 in advance (step ST205). Here, the predetermined concentration H1 is a hydrogen concentration H sufficient for the exhaust gas recirculation amount when the internal combustion engine 1-2 returns from the fuel cut state and the flow rate adjustment valve 36 is opened. For example, the hydrogen concentration H with respect to the exhaust gas when the fuel is reformed to the maximum by the reforming catalyst 31c.

  Next, when the acquired hydrogen concentration H is equal to or higher than the predetermined concentration H1, the processing unit 42 of the ECU 40 opens the flow rate adjustment valve 36 and the backflow prevention valve 39 (step ST206). Specifically, the processing unit 42 outputs the flow rate adjustment valve opening signal to the flow rate adjustment valve 36 and the backflow prevention valve opening / closing signal to the backflow prevention valve 39 via the input / output port 41, thereby The flow rate control valve control 36 is started, and the check valve 39 is opened. At this time, the processing unit 42 outputs an addition signal to the fuel addition device 55 and starts the addition control of the fuel addition device 55.

  Next, when the acquired hydrogen concentration H is less than the predetermined concentration H1, the processing unit 42 of the ECU 40 causes the exhaust gas containing the reformed fuel to contain a large amount of hydrogen. Specifically, first, the processing unit 42 of the ECU 40 acquires the temperature T of the fuel reformer 31 (step ST207). That is, the temperature of the reforming catalyst 31c detected by the reforming catalyst temperature sensor 31d as the reformer temperature detecting means is acquired.

  Next, the processing unit 42 of the ECU 40 determines whether or not the acquired temperature T is equal to or higher than a predetermined temperature T1 stored in the storage unit 43 in advance (step ST208). Here, the predetermined temperature T1 is a temperature (for example, 600 ° C.) necessary for activating the reforming catalyst 31c. In addition, the process part 42 of ECU40 repeats step ST207, when the acquired temperature T is less than predetermined temperature T1. Here, when the internal combustion engine 1-2 returns from the fuel cut state, high-temperature exhaust gas is exhausted from the internal combustion engine body 10 to the exhaust passage 32, and this exhaust gas is used as the fuel reformer 31. Therefore, the temperature T of the fuel reformer 31 can be raised.

  Next, when the acquired temperature T is equal to or higher than the predetermined temperature T1, the processing unit 42 of the ECU 40 outputs an addition signal to the fuel addition device 55, starts addition control of the fuel addition device 55, and converts it into exhaust gas. Fuel is added (step ST209). As a result, the temperature T becomes equal to or higher than the predetermined temperature T1, and the exhaust gas added with fuel is introduced into the fuel reformer 31 in which the reforming catalyst 31c is activated. Hydrogen is produced from the spent fuel. Then, the processing unit 42 of the ECU 40 acquires the hydrogen concentration H in the reformed fuel introduction passage 34 again (step ST204), and determines whether the acquired hydrogen concentration H is equal to or higher than a predetermined concentration H1 (step ST205). .

  As described above, when the hydrogen concentration H with respect to the exhaust gas containing the reformed fuel is equal to or higher than the predetermined concentration H1, that is, when the exhaust gas containing the reformed fuel contains sufficient hydrogen, The check valve 39 is opened. Therefore, when the internal combustion engine 1-2 returns from the fuel cut state and exhaust gas containing the reformed fuel is introduced into the intake passage 22, that is, each cylinder 11 of the internal combustion engine body 10, the reformed fuel is removed. Knocking or the like that occurs due to the small amount of hydrogen contained in the exhaust gas that is contained can be suppressed.

  In the second embodiment, the case where the addition control of the fuel addition device 55 is performed based on the temperature T of the fuel reformer 31, that is, the temperature of the reforming catalyst 31c has been described. However, the present invention is not limited to this. It is not something. For example, the temperature of exhaust gas (exhaust gas to which fuel introduced into the fuel reforming passage 31b is added or exhaust gas exhausted from the internal combustion engine body 10) that changes depending on the operating state of the internal combustion engine 1-2. The addition control of the fuel addition device 55 may be performed based on the above.

  Next, a control device and a control method for an internal combustion engine according to a third embodiment will be described. Here, the configuration example of the internal combustion engine according to the third embodiment is substantially the same as the configuration example of the internal combustion engine according to the second embodiment shown in FIG.

  Next, the operation of the ECU 40 that is the control device for the internal combustion engine 1-2 according to the third embodiment will be described. FIG. 5 is a diagram illustrating an operation flow of the control device for the internal combustion engine according to the third embodiment. In addition, the operation | movement same as operation | movement of the control apparatus of the internal combustion engine 1-1 concerning Example 1 shown in FIG. 2 is demonstrated easily.

  First, as shown in the figure, the processing unit 42 of the ECU 40 determines whether or not the internal combustion engine 1-2 is in a fuel cut state (step ST301). In addition, if the process part 42 judges that the internal combustion engine 1-2 is not a fuel cut state, it will repeat step ST301.

  Next, when determining that the internal combustion engine 1-2 is in the fuel cut state, the processing unit 42 of the ECU 40 closes the flow rate adjustment valve 36 and the backflow prevention valve (step ST302). At this time, the processing unit 42 stops the supply of fuel to the internal combustion engine 1-2 and the addition of fuel to the exhaust gas by not performing the injection control of the fuel injection valve 51 and the addition control of the fuel addition device 55. Then, the throttle valve 24 is closed.

  Here, as described above, since the internal combustion engine 1-2 is in the fuel cut state and the throttle valve 24 is closed, the dominant of the engine brake is changed, particularly the dominant, as in the first embodiment. It can suppress becoming worse. Therefore, the driver can obtain the desired vehicle deceleration by the engine brake when he / she releases his / her foot from an accelerator pedal (not shown).

  Further, when the internal combustion engine 1-2 is in a fuel cut state, that is, when the vehicle is decelerated, not only the flow rate adjustment valve 36 but also the backflow prevention valve 39 is closed. Can be further suppressed.

  Next, the processing unit 42 of the ECU 40 determines whether or not the condition for the internal combustion engine 1-2 to return from the fuel cut state is satisfied (step ST303). If processing unit 42 determines that internal combustion engine 1-2 does not satisfy the condition for returning from the fuel cut state, it repeats steps ST301 to ST303.

  Next, when the internal combustion engine 1-2 satisfies the condition for returning from the fuel cut state, the processing unit 42 of the ECU 40 determines whether or not the air-fuel ratio of the internal combustion engine 1-2 is stabilized (step ST304). ). At this time, the processing unit 42 outputs an injection signal to the fuel injection valve 51 and starts injection control of the fuel injection valve 51. Further, the processing unit 42 outputs a valve opening signal to the throttle valve 24 via the input / output port 41, and starts the valve opening control of the throttle valve 24.

  Here, when the internal combustion engine 1-2 returns from the fuel cut state, the processing unit 42 is based on the engine speed and the intake air amount and the fuel injection amount map stored in the storage unit 43. 1-2 is operated with stoichiometry (λ = 1), that is, the fuel injection amount is calculated so that the air-fuel ratio becomes the stoichiometric air-fuel ratio, and fuel is supplied from the fuel injection valve 51 to the internal combustion engine 1-2. However, the actual air-fuel ratio of the internal combustion engine 1-2 may not become the stoichiometric air-fuel ratio even if fuel is supplied to the internal combustion engine 1-2 based on the calculated fuel injection amount. Therefore, the processing unit 42 calculates the fuel injection amount based on the air-fuel ratio detected by the A / F sensor 37, that is, performs feedback control to stabilize the air-fuel ratio of the internal combustion engine 1-2. That is, the processing unit 42 determines whether or not the air-fuel ratio detected by the A / F sensor 37 has become the stoichiometric air-fuel ratio. If processing unit 42 determines that the air-fuel ratio of internal combustion engine 1-2 is not stable, it repeats step ST304.

  Next, the processing unit 42 of the ECU 40 acquires the hydrogen concentration H in the reformed fuel introduction passage 34 (step ST305).

  Next, the processing unit 42 of the ECU 40 calculates the hydrogen amount H ′ introduced into the intake path 20 of the internal combustion engine 1-2, that is, the intake path 22 based on the acquired hydrogen concentration H (step ST306). Specifically, the processing unit 42 determines the exhaust gas recirculation calculated based on the acquired hydrogen concentration H, the engine speed, the intake air amount, and the exhaust gas recirculation amount map stored in the storage unit 43. Calculate based on quantity.

  Next, the processing unit 42 of the ECU 40 corrects the fuel supply amount, that is, the fuel injection amount, based on the calculated hydrogen amount H ′ (step ST307). Specifically, the processing unit 42 is based on the amount of hydrogen H ′ introduced into each cylinder 11 of the internal combustion engine body 10 via the intake path 20 of the internal combustion engine 1-2 when the flow rate adjustment valve 36 is opened. Thus, the fuel injection amount is corrected to decrease so that the internal combustion engine 1-2 can perform a stoichiometric operation, that is, the air-fuel ratio of the internal combustion engine 1-2 becomes the stoichiometric air-fuel ratio.

  Next, the processing unit 42 of the ECU 40 opens the flow rate adjustment valve 36 and the backflow prevention valve 39 (step ST308). Specifically, the processing unit 42 outputs the flow rate adjustment valve opening signal to the flow rate adjustment valve 36 and the backflow prevention valve opening / closing signal to the backflow prevention valve 39 via the input / output port 41, thereby The flow rate control valve control 36 is started, and the check valve 39 is opened. At this time, the processing unit 42 outputs an injection signal to the fuel injection valve 51 so that the fuel of the fuel injection amount corrected for reduction is supplied to the internal combustion engine 1-2, and controls the injection of the fuel injection valve 51. Do. In addition, the processing unit 42 outputs an addition signal to the fuel addition device 55 and starts addition control of the fuel addition device 55. The processing unit 42 performs normal injection control after the fuel injection valve 51 is injection-controlled based on the fuel injection amount that has been corrected for decrease.

  As described above, after the air-fuel ratio of the internal combustion engine 1-2 is stabilized, the flow rate adjustment valve 36 and the backflow prevention valve 39 are opened, and the exhaust gas containing the reformed fuel is supplied to the intake path of the internal combustion engine 1-2. Introduced into each cylinder 11 of the internal combustion engine body 10 through 20. Therefore, even if the flow rate adjusting valve 36 is opened and the exhaust gas containing the reformed fuel is introduced into each cylinder 11 together with the fuel, the air-fuel ratio of the internal combustion engine 1-2 can be brought to the stoichiometric air-fuel ratio in a short time. Can do. Further, the fuel injection amount is corrected to decrease based on the hydrogen amount H ′ introduced into each cylinder 11 of the internal combustion engine body 10 via the intake passage 20 of the internal combustion engine 1-2. Therefore, even if the flow rate adjusting valve 36 is opened and the exhaust gas containing the reformed fuel is introduced into each cylinder 11 together with the fuel, the air-fuel ratio of the internal combustion engine 1-2 is prevented from greatly deviating from the stoichiometric air-fuel ratio. can do. As a result, it is possible to suppress the deterioration of the emission when the internal combustion engine 1-2 returns from the fuel cut state and the flow rate adjustment valve 36 opens.

  In the third embodiment, the flow rate adjustment valve 36 and the backflow prevention valve 39 may be gradually opened. Specifically, when the internal combustion engine 1-2 returns from the fuel cut state and the flow rate adjustment valve 36 opens, the ECU 40 determines that the flow rate adjustment valve 36 is The flow rate adjustment valve opening degree control is performed so as to gradually become the calculated opening degree, and the backflow prevention valve opening / closing control is performed so that the backflow prevention valve 39 is gradually fully opened. Accordingly, the amount of exhaust gas including the reformed fuel introduced into each cylinder 11 of the internal combustion engine body 10 via the intake passage 20 of the internal combustion engine 1-2 gradually increases, and each cylinder 11 of the internal combustion engine body 10 is increased. Since the amount of hydrogen introduced into the fuel gas gradually increases, it is possible to suppress the air-fuel ratio of the internal combustion engine 1-2 from greatly deviating from the stoichiometric air-fuel ratio. As a result, it is possible to suppress the deterioration of the emission when the internal combustion engine 1-2 returns from the fuel cut state and the flow rate adjustment valve 36 opens.

  In the second and third embodiments, the backflow prevention valve 39 for which the backflow prevention valve opening / closing control is performed by the ECU 40 is provided between the exhaust passage 32 and the exhaust gas introduction passage 33. However, the present invention is not limited to this. A check valve that opens and closes depending on the difference between the pressure in the exhaust passage 32 and the pressure in the exhaust gas introduction passage 33 may be provided.

In the second and third embodiments, since the A / F sensor 37 is provided, the ECU 40 is not limited to the stoichiometric operation, but may be a lean operation, for example. When the ECU 40 performs the stoichiometric operation of the internal combustion engine 1-2, an O ₂ sensor may be used instead of the A / F sensor 37.

  Next, a control device and a control method for an internal combustion engine according to a fourth embodiment will be described. Here, the configuration example of the internal combustion engine according to the fourth embodiment is substantially the same as the configuration example of the internal combustion engine according to the first embodiment shown in FIG.

  Next, the operation of the ECU 40 that is the control device for the internal combustion engine 1-1 according to the fourth embodiment will be described. FIG. 6 is a diagram illustrating an operation flow of the control device for the internal combustion engine according to the fourth embodiment.

  First, as shown in the figure, the processing unit 42 of the ECU 40 determines whether or not the vehicle on which the internal combustion engine 1-1 is mounted is decelerating (step ST401). Specifically, a change in vehicle speed per unit time detected by a vehicle speed sensor provided in a vehicle (not shown), whether or not the driver has lifted his / her foot from an accelerator pedal (not shown), that is, an accelerator pedal sensor input to the ECU 40 It can be determined based on whether or not the accelerator opening detected by 60 has become zero or almost zero.

  Next, when determining that the vehicle is decelerating, the processing unit 42 of the ECU 40 acquires the actual deceleration of the vehicle (step ST402). Specifically, the processing unit 42 changes the vehicle speed detected by the vehicle speed sensor per unit time, changes in the engine speed per unit time detected by the angle sensor, and a crank (not shown) of the internal combustion engine 1-1. It can be calculated from the current reduction ratio (transmission ratio) of the transmission to which the shaft is connected. The reduction ratio can be acquired based on the current position of the transmission detected from a position sensor (not shown) and the current vehicle speed detected by the vehicle speed sensor. At this time, the processing unit 42 stops the supply of fuel to the internal combustion engine 1-2 and the addition of fuel to the exhaust gas by not performing the injection control of the fuel injection valve 51 and the addition control of the fuel addition device 55. The throttle valve 24 is closed so that the upstream intake passage 22 and the downstream intake passage of the throttle valve 24 do not communicate with each other.

  Next, the processing unit 42 of the ECU 40 determines whether or not the acquired actual deceleration and the requested deceleration are the same (step ST403). Here, the required deceleration is the deceleration required by the engine brake based on the traveling state of the vehicle, that is, the vehicle speed. This required deceleration can be calculated from the current vehicle speed detected by the vehicle speed sensor or the current engine speed detected by the angle sensor and the current reduction ratio. The required deceleration is calculated in order to prevent the driver from feeling uncomfortable when the vehicle speed of the vehicle is high and the deceleration is large, resulting in rapid deceleration.

  Next, when the processing unit 42 of the ECU 40 determines that the acquired actual deceleration and the requested deceleration are the same, the current opening of the flow rate adjustment valve 36 is maintained (step ST404). As a result, the actual deceleration of the vehicle due to the engine brake generated by the pump loss obtained by closing the throttle valve while the flow rate adjustment valve 36 is open is maintained the same as the required deceleration. The

  Next, when determining that the acquired actual deceleration and the requested deceleration are not the same, the processing unit 42 of the ECU 40 determines whether or not the acquired actual deceleration is greater than the requested deceleration (step ST405).

  Next, when the processing unit 42 of the ECU 40 determines that the acquired actual deceleration is greater than the required deceleration, the opening degree of the flow rate adjustment valve 36 is increased (step ST406). Accordingly, when the intake passage 22 on the downstream side of the throttle valve 24 with which the reformed fuel introduction passage 34 communicates becomes negative pressure, the exhaust gas containing the reformed fuel in the reformed fuel introduction passage 34 is converted into the internal combustion engine. A large amount of air is introduced into the intake passage 20 of 1-1, that is, the intake passage 22 on the downstream side of the throttle valve 24. As a result, the pump loss obtained by closing the throttle valve while the flow rate adjusting valve 36 is open is reduced, the generated engine brake is reduced, and the actual deceleration of the vehicle is reduced. Then, the processing unit 42 of the ECU 40 acquires the actual deceleration of the vehicle again (step ST402), and determines whether or not the acquired actual deceleration and the requested deceleration are the same (step ST403).

  Next, if the process part 42 of ECU40 judges that the acquired actual deceleration is not larger than a request | requirement deceleration, it will reduce the opening degree of the flow regulating valve 36 (step ST407). Accordingly, when the intake passage 22 on the downstream side of the throttle valve 24 with which the reformed fuel introduction passage 34 communicates becomes negative pressure, the exhaust gas containing the reformed fuel in the reformed fuel introduction passage 34 is converted into the internal combustion engine. The intake passage 20 of 1-1, that is, the intake passage 22 on the downstream side of the throttle valve 24 is not so much introduced. As a result, the pump loss obtained by closing the throttle valve while the flow rate adjusting valve 36 is open increases, the engine brake generated increases, and the actual deceleration of the vehicle increases. Then, the processing unit 42 of the ECU 40 acquires the actual deceleration of the vehicle again (step ST402), and determines whether or not the acquired actual deceleration and the requested deceleration are the same (step ST403).

  As described above, the ECU 40 adjusts the opening degree of the flow rate adjustment valve 36 based on the difference between the actual deceleration and the required deceleration when the vehicle is decelerated. In other words, the ECU 40 determines that the actual deceleration of the vehicle due to the engine brake generated by the pump loss obtained by closing the throttle valve 24 when the flow rate adjustment valve 36 is open is the same as the required deceleration. Thus, the opening degree of the flow rate adjustment valve 36 is adjusted. As a result, it is possible to suppress the change in the dominant of the engine brake with respect to the required deceleration required when the vehicle is decelerated. Therefore, the deceleration of the vehicle required according to the running state of the vehicle can be obtained by the engine brake.

  As described above, the control device and the control method for an internal combustion engine according to the present invention are useful for an internal combustion engine including a fuel reformer that reforms fuel added to exhaust gas, and particularly when the internal combustion engine is decelerated. It is suitable to suppress the change of the engine braking.

1 is a diagram illustrating a configuration example of an internal combustion engine according to a first embodiment. FIG. 3 is a diagram illustrating an operation flow of the control device for the internal combustion engine according to the first embodiment. FIG. 3 is a diagram illustrating a configuration example of an internal combustion engine according to a second embodiment. FIG. 6 is a diagram illustrating an operation flow of the control device for the internal combustion engine according to the second embodiment. FIG. 9 is a diagram illustrating an operation flow of the control device for the internal combustion engine according to the third embodiment. FIG. 10 is a diagram illustrating an operation flow of the control device for the internal combustion engine according to the fourth embodiment.

Explanation of symbols

1-1, 1-2 Internal combustion engine 10 Internal combustion engine body 11 Cylinder 20 Intake passage 21 Air cleaner 22 Intake passage 23 Air flow meter 24 Throttle valve 30 Exhaust passage 31 Fuel reformer 31a Hollow portion 31b Fuel reforming passage 31c Reforming catalyst 31d Reforming catalyst temperature sensor (reformer temperature detecting means)
32 Exhaust passage 33 Exhaust gas introduction passage 34 Reformed fuel introduction passage 35 Reformed fuel cooling device 36 Flow rate adjusting valve 37 A / F sensor 38 Hydrogen concentration detection sensor (hydrogen concentration detection means)
39 Backflow prevention valve 51 Fuel injection valve 52 Fuel tank 53 Fuel pump 54 Fuel passage 55 Fuel addition device (fuel addition means)
56 branch passage

Claims (9)

An exhaust gas introduction passage for introducing exhaust gas in the exhaust path of the internal combustion engine into the fuel reformer;
Fuel addition means for adding fuel to the exhaust gas introduced into the fuel reformer;
A fuel reformer for reforming the added fuel;
A reformed fuel introduction passage for introducing exhaust gas containing the reformed fuel into an intake path of an internal combustion engine;
A flow rate adjusting valve for adjusting the amount of exhaust gas containing the reformed fuel introduced into the intake path of the internal combustion engine;
In a control device for an internal combustion engine comprising:
A fuel cut determining means for determining a fuel cut state of the internal combustion engine;
When it is determined that the internal combustion engine is in a fuel cut state, the control device for the internal combustion engine, wherein the flow rate adjustment valve is closed. A backflow prevention valve is further provided between the exhaust path of the internal combustion engine and the exhaust gas introduction passage;
2. The control device for an internal combustion engine according to claim 1, wherein when it is determined that the internal combustion engine is in a fuel cut state, the flow rate adjustment valve and the backflow prevention valve are closed. A hydrogen concentration detecting means for detecting a hydrogen concentration contained in the exhaust gas containing the reformed fuel;
When it is determined that the internal combustion engine is returning from a fuel cut state, the flow rate adjustment valve and the backflow prevention valve are opened when the detected hydrogen concentration exceeds a predetermined concentration. Item 3. A control device for an internal combustion engine according to Item 2. Reformer temperature detection means for detecting the temperature of the fuel reformer,
When the detected hydrogen concentration is less than a predetermined concentration and the detected temperature of the fuel reformer is equal to or higher than a predetermined temperature, the exhaust gas introduced into the fuel reformer by the fuel addition means The control device for an internal combustion engine according to claim 3, wherein fuel is added.   The flow rate adjustment valve and the backflow prevention valve are opened after the air-fuel ratio of the internal combustion engine is stabilized when it is determined that the internal combustion engine is returning from a fuel cut state. 3. The control device for an internal combustion engine according to 2. Hydrogen concentration detecting means for detecting the hydrogen concentration contained in the exhaust gas containing the reformed fuel;
Hydrogen amount calculating means for calculating the amount of hydrogen introduced into the intake path of the internal combustion engine based on the detected hydrogen concentration;
Further comprising
The hydrogen amount calculation means calculates the hydrogen amount when the flow rate adjustment valve and the backflow prevention valve are closed based on the detected hydrogen concentration, and opens the flow rate adjustment valve and the backflow prevention valve. 6. The control device for an internal combustion engine according to claim 5, wherein the fuel supply amount of the fuel supplied to the internal combustion engine is corrected based on the calculated hydrogen amount. An exhaust gas introduction passage for introducing exhaust gas into the fuel reformer;
Fuel addition means for adding fuel to the exhaust gas introduced into the fuel reformer;
A fuel reformer for reforming the added fuel;
A reformed fuel introduction passage for introducing exhaust gas containing the reformed fuel into an intake path of the internal combustion engine;
A flow rate adjusting valve for adjusting the amount of exhaust gas containing the reformed fuel introduced into the intake path of the internal combustion engine;
In a control device for an internal combustion engine comprising:
An actual deceleration detecting means for detecting an actual deceleration at the time of deceleration of the vehicle on which the internal combustion engine is mounted;
A required deceleration calculation means for calculating a required deceleration required when the vehicle equipped with the internal combustion engine is decelerated;
Further comprising
The flow rate adjusting valve adjusts an amount of exhaust gas including the reformed fuel based on a difference between the detected actual deceleration and the calculated required deceleration. Control device. The fuel reformer reforms the fuel added to the exhaust gas in the exhaust path of the internal combustion engine introduced into the fuel reformer, and the exhaust gas containing the reformed fuel is converted into the intake path of the internal combustion engine. In the control method of the internal combustion engine to be introduced into
A fuel cut determination procedure for determining a fuel cut state of the internal combustion engine;
When determining that the internal combustion engine is in a fuel cut state, a procedure for closing the flow rate adjustment valve;
A control method for an internal combustion engine comprising: The fuel reformer reforms the fuel added to the exhaust gas in the exhaust path of the internal combustion engine introduced into the fuel reformer, and the exhaust gas containing the reformed fuel is converted into the intake path of the internal combustion engine. In the control method of the internal combustion engine to be introduced into
An actual deceleration detection procedure for detecting an actual deceleration at the time of deceleration of a vehicle on which the internal combustion engine is mounted;
A required deceleration calculation procedure for calculating a required deceleration required when the vehicle equipped with the internal combustion engine is decelerated;
Based on the difference between the detected actual deceleration and the calculated required deceleration, the amount of exhaust gas including reformed fuel introduced into the intake path of the internal combustion engine is adjusted by the flow rate adjusting valve. Procedure and
A control method for an internal combustion engine comprising:

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