JP2007239690A - Internal combustion engine - Google Patents

Abstract

To efficiently activate an exhaust purification catalyst early using a reformed gas, and to generate a reformed gas by exothermic reaction of a predetermined fuel with a fuel reforming catalyst 51b of a fuel reformer 50 In the internal combustion engine 1 that can be operated using the reformed gas as a fuel, the reformed gas supplied from the fuel reformer 50 and / or the exhaust gas purifier 42 is supplied to the exhaust gas purifier 42 on the exhaust path 40. An exhaust purification catalyst that can exchange heat with the fuel reforming catalyst is provided. For example, the exhaust purification device 42 includes exhaust purification means 421 in which an exhaust gas passage 421a having an exhaust purification catalyst and a reformed gas passage 421b adjacent to the exhaust gas passage 421a are formed.
[Selection] Figure 1

Description

  The present invention relates to an internal combustion engine that can be operated with a reformed fuel produced by reforming a predetermined fuel such as a hydrocarbon-based fuel.

  2. Description of the Related Art Conventionally, there is known an internal combustion engine in which a reformed gas generated from a predetermined fuel by a fuel reformer is supplied to a combustion chamber and operated with the reformed gas to reduce harmful components such as HC components in exhaust gas. It has been. For example, in this type of internal combustion engine, a mixture of hydrocarbon fuel and air is supplied to a fuel reformer and reformed by a high-temperature reforming catalyst, and hydrogen gas and carbon monoxide generated thereby are used. The following Patent Document 1 discloses that a reformed gas mainly composed of gas is supplied to an intake passage and burned in a combustion chamber. In Patent Document 1, a technique for exchanging heat between the reformed gas and the exhaust gas is disclosed.

JP 2004-239203 A

  However, even in such an internal combustion engine with excellent emission performance, even if it is operated with only the reformed gas from the start of the engine to the end of the warm-up operation, harmful components in the exhaust gas can be reduced. There was a disadvantage that the emission performance was not improved. In particular, such inconvenience appears remarkably immediately after the engine is started.

  Specifically, immediately after the engine is started, the atomization of the hydrocarbon-based fuel supplied to the fuel reformer and the poor mixing with the air are likely to occur, and the reforming reaction can be performed on the carrier temperature of the reforming catalyst. Since it is difficult to raise the temperature to a predetermined temperature, the hydrocarbon fuel remains without being reformed by the reforming catalyst. Therefore, in the internal combustion engine immediately after the engine is started, harmful components such as HC are generated in the combustion chamber with the combustion of the unreformed fuel and are discharged together with the exhaust gas.

  In general, carbon monoxide gas has a slower combustion speed than hydrogen gas, which is excellent in combustibility. If carbon monoxide gas is contained in the reformed gas, misfiring and poor combustion are likely to occur. In this case, the carbon monoxide gas is discharged without being burned. In particular, in this internal combustion engine, hydrogen gas and carbon monoxide gas are contained in the reformed gas generated from hydrocarbon fuel and air at a substantially equal ratio, so that the mixture of reformed gas and air is mixed. The combustion limit on the lean side is narrow, and misfires and poor combustion are likely to occur.

  Further, immediately after the engine is started, generally, an accurate intake air amount to the combustion chamber cannot be measured, so that the air-fuel ratio of the mixture of reformed gas and air cannot be accurately controlled. Set to the over-rich side to prevent misfire due to an over-thin mixture. However, in recent years, unless the air-fuel ratio is set to the lean side, it is not possible to comply with the strict exhaust gas regulations. For this reason, when such setting is performed, the combustion limit on the lean side of the mixture is limited. If it is narrow, misfires and poor combustion easily occur, and carbon monoxide gas is discharged as it is.

  As described above, when harmful components are present in the exhaust gas, the harmful components are generally purified by the exhaust purification catalyst. Generally, however, the bed temperature of the exhaust purification catalyst immediately after starting the engine has reached the activation temperature. Therefore, harmful components in the exhaust gas generated immediately after starting the engine cannot be purified and are discharged outside as they are.

  Here, Patent Document 1 discloses a technique for exchanging heat between the reformed gas and the exhaust gas upstream of the exhaust purification device. However, such a technique is disclosed as the reformed gas sucked into the combustion chamber. As is clear from the purpose of cooling the exhaust gas, the disclosed configuration cannot sufficiently raise the bed temperature of the exhaust purification catalyst using the heat of the reformed gas.

  Therefore, an object of the present invention is to provide an internal combustion engine that can improve the disadvantages of the conventional example and can activate the exhaust purification catalyst efficiently and quickly.

  In order to achieve the above object, according to the first aspect of the present invention, it is possible to generate a reformed gas by causing a predetermined fuel to react exothermically with a fuel reforming catalyst of a fuel reformer, and the reformed gas can be used as fuel. In an internal combustion engine, an exhaust purification device that can exchange heat with an exhaust purification device on an exhaust path between the reformed gas supplied from the fuel reforming device and / or a fuel reforming catalyst provided in the exhaust purification device. A catalyst is provided.

  In the internal combustion engine according to the first aspect, heat can be transferred from the high temperature reformed gas or the fuel reforming catalyst that has become high temperature by the reforming reaction to the low temperature exhaust purification catalyst. The temperature rises faster than the bed temperature is raised only with exhaust gas.

  In order to achieve the above object, in the invention according to claim 2, in the internal combustion engine according to claim 1, there is provided an exhaust gas passage having an exhaust purification catalyst and a reformed gas passage adjacent to the exhaust gas passage. The formed exhaust gas purification means is provided in the exhaust gas purification device.

  Therefore, in the internal combustion engine according to claim 2, the temperature of the exhaust purification catalyst in the exhaust gas passage can be raised by the high-temperature reformed gas flowing in the reformed gas passage.

  In order to achieve the above object, according to a third aspect of the present invention, in the internal combustion engine according to the second aspect, a fuel reforming catalyst for an exhaust purification device is provided at least in part on the reformed gas passage, Control means is provided for controlling the fuel reformer to generate unreformed fuel along with the reformed gas.

  Therefore, in the internal combustion engine according to claim 3, the temperature of the exhaust purification catalyst in the exhaust gas passage is raised by the high-temperature reformed gas flowing in the reformed gas passage, and the fuel reforming in the reformed gas passage is performed. The bed temperature of the exhaust purification catalyst in the exhaust gas passage is raised through the fuel reforming catalyst by the exothermic reaction at the time of reforming of the unreformed fuel occurring in the catalyst.

  In order to achieve the above object, in the invention according to claim 4, in the internal combustion engine according to claim 1, 2 or 3, a reformed gas storage tank for storing the reformed gas after heat exchange, and this Control means for starting the engine after a predetermined amount of the reformed gas is stored in the reformed gas storage tank.

  In the internal combustion engine according to claim 4, since the exhaust purification catalyst is activated before the engine is started, harmful components in the exhaust gas can be purified immediately after the engine is started. Further, since the reformed gas generated before the engine is started can be stored in the reformed gas storage tank, it is possible to prevent the reformed gas supply path from being damaged.

  In order to achieve the above object, according to a fifth aspect of the present invention, in the internal combustion engine according to the first, second, third or fourth aspect, an oxygen supply for supplying oxygen to the reformed gas before heat exchange. A device is provided.

  In the internal combustion engine according to the fifth aspect, since the high temperature reformed gas can be combusted to further increase the temperature, the bed temperature of the exhaust purification catalyst can be raised more quickly.

  In the internal combustion engine according to the present invention, the exhaust gas purification device is configured so that the high-temperature reformed gas or the fuel reforming catalyst and the exhaust gas purification catalyst are heat-exchanged. It is possible to activate the exhaust purification catalyst early by effectively utilizing the heat of the reforming catalyst.

  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.

  A first embodiment of an internal combustion engine according to the present invention will be described with reference to FIGS.

  Reference numeral 1 in FIG. 1 indicates the internal combustion engine of the first embodiment. The internal combustion engine 1 includes an engine body 10 having first to fourth cylinders 11a to 11d, an intake passage 20 for supplying air from the outside to the combustion chambers of the first to fourth cylinders 11a to 11d, First to fourth fuel injectors 30a to 30d for injecting fuels to be burned in the respective combustion chambers (here, hydrocarbon-based fuels such as gasoline) and exhaust gases discharged from the respective combustion chambers An exhaust path 40 for releasing the fuel into the atmosphere, and a fuel reformer 50 that generates reformed fuel from a predetermined fuel and supplies the reformed fuel to the intake path 20. The first to fourth fuel injection devices 30a to 30d are supplied with hydrocarbon fuel via the fuel pump 61 and the fuel supply passage 62 shown in FIG.

  First, in the intake passage 20 of the internal combustion engine 1 of the first embodiment, an intake passage 21 for sucking and guiding air from the outside, an air cleaner 22 for removing foreign matters such as dust from the introduced air, and an intake from the outside An air flow meter 23 for detecting the amount of air; a throttle valve 24 for adjusting the amount of intake air into the combustion chambers of the first to fourth cylinders 11a to 11d; a throttle valve actuator 25 for driving the throttle valve 24 to open and close; A throttle opening sensor 26 that detects the opening of the throttle valve 24 and an intake manifold 27 that guides the air adjusted by the throttle valve 24 to the combustion chambers of the first to fourth cylinders 11a to 11d are provided. ing.

  Here, the detection signals of the air flow meter 23 and the throttle opening sensor 26 are transmitted to an electronic control unit (ECU) 70 as control means. Therefore, in this electronic control unit 70, the intake air amount from the outside is calculated based on the detection signal of the air flow meter 23, and the opening degree of the throttle valve 24 is detected based on the detection signal of the throttle opening degree sensor 26. .

  Further, the electronic control unit 70 issues a control command for the valve opening angle of the throttle valve 24 to the throttle valve actuator 25, and supplies a desired amount of air according to the valve opening angle to the first to fourth cylinders 11a. The throttle valve 24 is driven to open and close to be sucked into the combustion chamber of ˜11d.

  In the first embodiment, the first to fourth fuel injection devices 30a to 30d described above are disposed in the intake ports of the first to fourth cylinders 11a to 11d in the engine body 10, respectively. . For this reason, in the internal combustion engine 1, fuel in each intake port injected from the first to fourth fuel injection devices 30a to 30d together with air enters the combustion chambers of the first to fourth cylinders 11a to 11d. After being inhaled, the respective air-fuel mixtures are ignited from the first to fourth spark plugs 12a to 12d. Here, the electronic control unit 70 of the first embodiment controls the fuel injection timings of the first to fourth fuel injection devices 30a to 30d and the ignition timings of the first to fourth spark plugs 12a to 12d. To control. The first to fourth fuel injection devices 30a to 30d may be arranged to inject fuel directly into the combustion chambers of the first to fourth cylinders 11a to 11d, respectively.

  In the internal combustion engine 1, the in-cylinder gas after ignition is discharged to the exhaust path 40 through the exhaust ports of the first to fourth cylinders 11 a to 11 d in the engine body 10. The exhaust path 40 according to the first embodiment includes an exhaust manifold 41 that collects exhaust gases discharged to the respective exhaust ports into one path, and an exhaust purification unit 421 that purifies harmful components in the exhaust gas. An exhaust purification device 42.

By the way, in general, in an internal combustion engine, by using hydrogen as a fuel at the time of combustion, a CO (carbon monoxide) component, a CO ₂ (carbon dioxide) component, It is known that harmful components such as HC (hydrocarbon) components can be greatly reduced. Therefore, since the bed temperature of the exhaust purification catalyst such as the three-way catalyst in the exhaust purification means 421 (hereinafter also referred to as “exhaust catalyst carrier temperature”) does not reach the activation temperature, harmful components in the exhaust gas are purified. Under difficult circumstances, combustion with hydrogen, which can suppress emission of harmful components, is effective in improving emission performance. Under such circumstances, the engine is cold, such as when the engine is started, but the exhaust catalyst carrier temperature of the exhaust purification device 42 once activated is lower than the activation temperature by, for example, light load operation. Also included when it has become.

  Therefore, in the first embodiment, hydrogen gas as reformed fuel is generated by the fuel reformer 50 described above in a state where the exhaust purification device 42 is not activated, and this is used as fuel during combustion. To be able to operate. In the first embodiment, hydrogen gas is generated by reforming the hydrocarbon fuel. The fuel reformer 50 can be constructed by a well-known configuration in the technical field. For example, in the first embodiment, a mixture of hydrocarbon fuel and oxygen is used as hydrogen gas and carbon monoxide gas. The reformed gas is reformed into a reformed gas whose main component is the same, and the one having the following configuration is supplied to the intake passage 20. Hereinafter, the fuel reformer 50 of the first embodiment will be described in detail.

  The fuel reformer 50 according to the first embodiment includes a fuel reforming means 51 that generates a reformed gas mainly composed of hydrogen gas and carbon monoxide gas from a hydrocarbon-based fuel and air (oxygen), and the fuel reformer. A fuel supply means 52 for supplying hydrocarbon fuel to the means 51, an air supply means 53 for supplying air to the fuel reforming means 51, and a reformed gas generated by the fuel reforming means 51 for the intake passage 20 And a reformed gas supply path 54 leading to the side.

  Specifically, as shown in FIG. 2, the fuel reforming means 51 includes a mixing unit 51 a in which the hydrocarbon-based fuel supplied from the fuel supply means 52 and the air supplied from the air supply means 53 are mixed. There is provided a fuel reforming catalyst 51b for reforming the mixture of the hydrocarbon fuel and air (oxygen) to generate a reformed gas mainly composed of hydrogen gas and carbon monoxide gas. Here, as the fuel reforming catalyst 51b of the first embodiment, the catalyst carrier is heated using heating means (not shown) such as a heater, and the catalyst carrier is heated to a predetermined temperature at which the reforming reaction can be performed. Thus, a so-called electric heating type reforming catalyst is used to initiate the reforming reaction. Therefore, in the fuel reforming means 51 of the first embodiment, an electrode 51c for supplying electric power from the power source (for example, the vehicle battery 81 shown in FIG. 2) to the heating means, and energization to the electrode 51c. An on / off switch 51d that switches between non-energization is provided. Note that a burner or the like may be used as the heating means.

  Further, as the fuel supply means 52 of the first embodiment, for example, a so-called fuel injection valve for injecting the hydrocarbon-based fuel supplied through the fuel pump 61 and the fuel supply passage 63 shown in FIG. Use.

  Furthermore, the air supply means 53 of the first embodiment includes a pump 53a that pumps air, an air supply path 53b that guides the air discharged from the pump 53a to the mixing unit 51a, and the air supply path 53b. And an air supply amount adjusting valve 53c that adjusts the air supply amount to the mixing unit 51a.

  Here, in the fuel reformer 50 of the first embodiment, the reformed gas in the reformed gas supply path 54 is individually supplied to the combustion chambers of the first to fourth cylinders 11a to 11d. As shown in FIG. 1, first to fourth reformed gas supply devices 55a to 55d are provided corresponding to the first to fourth cylinders 11a to 11d, respectively. The first to fourth reformed gas supply devices 55a to 55d are arranged in the respective branch passages of the first to fourth cylinders 11a to 11d in the intake manifold 27.

  The fuel reformer 50 according to the first embodiment generates reformed gas in accordance with an instruction from the electronic control unit 70, and supplies the reformed gas to the combustion chambers of the first to fourth cylinders 11a to 11d. .

  Specifically, the electronic control unit 70 switches the on / off switch 51d to the energized side when the generation of the reformed gas is required, and raises the fuel reforming catalyst 51b to a predetermined temperature. The electronic control unit 70 controls the operation of the fuel supply means 52 and the air supply means 53 (the pump 53a and the air supply amount adjustment valve 53c), so that the amount of carbonization corresponding to the desired amount of reformed gas is generated. Hydrogen fuel and air are supplied to the mixing unit 51a. As a result, in the fuel reformer 50, the mixture of the hydrocarbon fuel and air undergoes a reforming reaction in the fuel reforming catalyst 51b, and reforming is performed mainly with hydrogen gas and carbon monoxide gas. Gas is generated. Thereafter, the fuel reformer 50 is controlled to drive the first to fourth reformed gas supply devices 55a to 55d by the electronic control unit 70, so that the reformed gas is supplied to the respective branch passages of the intake manifold 27. Supply. The reformed gas is combusted after being sucked into the first to fourth cylinders 11a to 11d together with the air on the respective diversion passages.

  In the internal combustion engine 1 of the first embodiment having such a configuration, the fuel reforming device 50 is operated and operated with the reformed gas, whereby harmful components in the exhaust gas can be greatly reduced. . Therefore, in a situation where the exhaust purification device 42 is not activated, good emission performance can be ensured by executing the operation with the reformed gas.

  Here, even under such circumstances, for example, depending on driving conditions such as athletic performance desired by the driver and driving environment, it may be preferable to operate with a hydrocarbon-based fuel rather than driving with reformed gas. . However, in recent years, exhaust gas regulations tend to be tightened every year. Under such circumstances, it is not desirable to operate with hydrocarbon fuels until the emission performance is sacrificed. On the other hand, it is not preferable to continue operation with reformed gas even though operation with hydrocarbon fuel is desired, and it is possible to operate with hydrocarbon fuel as soon as possible. desirable.

  Immediately after the fuel reformer 50 is started, the supplied hydrocarbon-based fuel is likely to be poorly atomized or poorly mixed with air, so that it is difficult to control the air-fuel ratio of these air-fuel mixtures. Since it is difficult to raise the bed temperature of the catalyst 51b to a predetermined temperature at which the reforming reaction can be performed, there are cases where all the hydrocarbon fuels cannot be completely reformed. For this reason, in such a case, the unreformed fuel is burned in the combustion chamber to generate harmful components. Therefore, in a situation where the exhaust purification device 42 is not activated, the harmful components are removed from the exhaust purification device 42. It cannot be purified by, and the emission performance deteriorates.

  Therefore, the internal combustion engine 1 is configured to quickly raise the exhaust catalyst carrier temperature of the exhaust purification device 42 to the activation temperature (approximately 350 ° C. or higher) in order to cope with these events satisfactorily. Specifically, the reforming reaction that occurs in the fuel reforming catalyst 51b of the fuel reforming apparatus 50 as described above is an exothermic reaction, and the reformed gas generated through this reaction becomes a high temperature (about 950 ° C.). Therefore, by utilizing the heat of the high-temperature reformed gas, the temperature of the exhaust catalyst carrier of the exhaust purification device 42 can be easily increased as compared with the case where the temperature is raised only by the exhaust gas. Therefore, in the internal combustion engine 1, the exhaust purification device 42 is configured so that heat can be exchanged between the high-temperature reformed gas and the exhaust purification catalyst.

  Hereinafter, a specific configuration of the exhaust emission control device 42 of the first embodiment will be described in detail with reference to FIGS. 3 to 5. Reference numeral 42A in FIG. 3 shows the exhaust purification apparatus of the first embodiment, and reference numeral 421A in each figure shows the exhaust purification means of the first embodiment.

  The exhaust purification device 42A of the first embodiment purifies harmful components in the exhaust gas in the exhaust purification means 421A in which the honeycomb-shaped exhaust gas passage 421a shown in FIG. 4 is formed. Accordingly, an exhaust purification catalyst is disposed in each exhaust gas passage 421a of the exhaust purification means 421A. In the first embodiment, the exhaust purification catalyst and the reformed gas in each exhaust gas passage 421a are arranged. In order to realize heat exchange between the exhaust gas passages 421a, a plurality of reformed gas passages 421b for allowing the reformed gas to flow are provided in the exhaust gas purifying means 421A.

  Specifically, in the exhaust gas purification means 421A of the first embodiment, exhaust gas that purifies harmful components in the exhaust gas at a predetermined activation temperature (approximately 350 ° C. or higher) on each inner wall surface of the honeycomb-shaped exhaust gas passage 421a. A purification catalyst is disposed (for example, coated), and a honeycomb-like reformed gas passage 421b is formed adjacent to each exhaust gas passage 421a. For example, as shown in FIG. 4, the exhaust gas purifying means 421A includes so-called exhaust gas passages 421a and reformed gas passages 421b that are substantially orthogonal to each other so as to be adjacent to each other and are alternately arranged in the vertical direction in FIG. A cross-flow type exhaust purification catalyst carrier is conceivable.

As shown in FIG. 5, this type of exhaust purification means 421A includes a plurality of flat foils 421A ₁ arranged with a predetermined interval between planes, and first and second alternatingly arranged between the flat foils 421A ₁ . It consists of corrugated foils 421A ₂ and 421A ₃ . Here, arranged with its first corrugated sheet 421A ₂ a second corrugated sheet 421A ₃ as the respective waveforms are orthogonal, two flat to both sides and the clamping them the first corrugated sheet 421A ₂ waveforms a plurality of spaces surrounded by the plane of the foil 421A ₁ and each exhaust gas passage 421a, surrounded by its second corrugated sheet 421A of ₃ waveforms sided and two flat foils 421A ₁ plane which sandwich this Each of the plurality of spaces is defined as a reformed gas passage 421b. In other words, this exhaust purification means 421A has a honeycomb layer having a plurality of exhaust gas passages 421a formed by a single first wave foil 421A ₂ and a plurality of reformers formed by a single second wave foil 421A ₃ . It has a multilayer structure of honeycomb layers having gas passages 421b. In this exhaust gas control means 421A, disposing the exhaust gas purifying catalyst on both sides and the plane of the flat sheet 421A ₁ facing the respective surfaces of the first corrugated sheet 421A ₂ waveforms.

Therefore, in the first embodiment, the heat of the high-temperature reformed gas flowing through the reformed gas passage 421b is converted to the flat foil 421A by the exhaust gas purification means 421A having the exhaust gas passage 421a and the reformed gas passage 421b. ₁ is transmitted to the exhaust purification catalyst via ₁ , and the bed temperature of the exhaust purification catalyst can be quickly raised.

Here, the exhaust gas purifying means 421A causes the second corrugated foil 421A ₃ to be sandwiched between the flat foils 421A ₁ at both ends on the outermost side (the outer side in the vertical direction in FIG. 4), and the reformed gas passage 421b is exhausted to the exhaust gas. It is preferable to configure so as to be located outside the passage 421a. As a result, since all the exhaust gas passages 421a of the exhaust purification means 421A can be sandwiched by the reformed gas passages 421b, cooling of the exhaust purification catalyst due to the ambient temperature outside the exhaust purification means 421A is suppressed, and all exhaust gases are suppressed. The bed temperature of the exhaust purification catalyst in the gas passage 421a can be raised uniformly.

Furthermore, the exhaust gas control means 421A, the height of the honeycomb layer of the exhaust gas passage 421a h1 height (= the first corrugated sheet 421A maximum thickness of ₂₎ honeycomb layer of the reformed gas passage 421b h2 (= second it is preferably configured to be higher than the corrugated sheet maximum thickness of 421A _3). Thereby, since the cross-sectional area of the exhaust gas passage 421a can be increased, the engine output can be improved by reducing the exhaust pressure. For example, when the air-fuel ratio of the generated reformed gas is “5”, if each of the combustion chambers is diluted with air and a mixture of reformed gas having an air-fuel ratio of 15 or more is supplied, the reformed gas The amount is about 1/3 or less of the exhaust gas discharged from the combustion chamber.

  Further, the exhaust purification device 42A according to the first embodiment guides the reformed gas generated by the fuel reformer 50 to the reformed gas passage 421b, and therefore between the fuel reforming means 51 and the reformed gas supply passage 54. To intervene. As a result, a high temperature (approximately 950 ° C.) reformed gas in which the temperature drop is suppressed as much as possible can be caused to flow into the reformed gas passage 421b of the exhaust purification means 421A, so that the bed temperature of the exhaust purification catalyst can be increased more quickly. Can be made.

  Here, the reformed gas that has passed through the reformed gas passage 421b is injected from the first to fourth reformed gas supply devices 55a to 55d into the respective shunt passages of the intake manifold 27, together with the air from the first. It is sucked into the fourth cylinders 11a to 11d and burned. Therefore, in the internal combustion engine 1, since the harmful components in the exhaust gas after combustion are greatly reduced as described above, good emission performance can be ensured. On the other hand, even with such exhaust gas, harmful components may exist due to, for example, the above-described unreformed fuel. However, in the internal combustion engine 1, the exhaust purification device 42 </ b> A is heated by the high-temperature reformed gas. Since early activation is achieved, the harmful components can be purified from an early stage.

  As described above, the internal combustion engine 1 according to the first embodiment employs a configuration in which the heat of the high-temperature reformed gas is transferred to the exhaust purification catalyst. The temperature of the exhaust purification device 42A can be activated early by raising the temperature to the activation temperature earlier than the temperature rise. Therefore, in this internal combustion engine 1, even if harmful components are generated by the operation with the reformed gas, it can be purified by the exhaust purification device 42A, and the combustion with the hydrocarbon-based fuel can be performed at an early stage. Therefore, it is possible to realize optimal combustion control according to desired operating conditions.

  Further, in this type of internal combustion engine 1, if the reformed gas is sucked into the combustion chamber at a high temperature, the suction efficiency is deteriorated and inconveniences such as a decrease in output are caused. Generally, a cooler or the like is provided. However, in this internal combustion engine 1, since the heat of the high-temperature reformed gas is absorbed by the exhaust purification catalyst and the exhaust gas in the exhaust purification means 421A, the reformed gas is sent to each combustion chamber without being cooled again. Thus, the effects of reducing the number of parts and cost can be obtained.

  By the way, even if the exhaust purification device 42A is activated early by the above-described configuration, immediately after the engine is started when the reformed gas is generated, the exhaust purification catalyst can be immediately raised to the activation temperature. It is not always possible.

  Therefore, in the internal combustion engine 1 of the first embodiment, it is preferable to provide the electronic controller 70 with a warm-up control function before starting the engine that activates the exhaust purification device 42A before starting the engine and starts the engine after activation. .

  The warm-up control function before starting the engine is configured, for example, to operate the fuel reformer 50 when detecting an ignition ON signal or the like before starting the engine, and generate high-temperature reformed gas before starting the engine. Is. As a result, in the internal combustion engine 1, the generated reformed gas can pass through the reformed gas passage 421b of the exhaust purification means 421A to raise the bed temperature of the exhaust purification catalyst, and therefore the exhaust purification device 42A. Can be activated before the engine starts.

  At this time, since the internal combustion engine 1 has not yet been started, the reformed gas after the heat exchange loses its place on the reformed gas supply path 54. For this reason, in this state, the generated reformed gas does not flow into the reformed gas passage 421b, and the bed temperature of the exhaust purification catalyst cannot be raised. Furthermore, the internal pressure increases with an increase in the amount of reformed gas produced, and the reformed gas supply path 54 may be damaged. Therefore, when the internal combustion engine 1 is configured to execute the warm-up control before starting the engine, the reformed gas storage tank 56 shown in FIG. 54 is provided. Thereby, the early activation of the exhaust purification device 42A before the engine start can be surely executed, and further, the breakage of the reformed gas supply path 54 and the like can be prevented.

  Further, the warm-up control function before starting the engine is configured to start the internal combustion engine 1 after the exhaust purification device 42A is activated. For this reason, in such warm-up control, activation determination conditions that can be determined for the activation are set.

  As the activation determination condition, it is most accurate and reliable to use the bed temperature of the exhaust purification catalyst directly detected by a temperature sensor (not shown). Gas temperature can also be used. For example, the temperature of the exhaust gas that has passed through the exhaust gas passage 421a of the exhaust purification means 421A is detected from the exhaust temperature sensor 43 shown in FIG. 1, and if the exhaust gas temperature is equal to or higher than a predetermined value obtained in advance through experiments or the like, the exhaust purification is performed. It is determined that the device 42A is activated. Since the exhaust gas temperature and the bed temperature of the exhaust purification catalyst are substantially the same temperature, the activation temperature of the exhaust purification catalyst may be set for the predetermined value.

  Further, the amount of reformed gas generated or the amount of reformed gas stored in the reformed gas storage tank 56 that is the same amount is detected, and the exhaust gas is purified when this amount exceeds a predetermined amount obtained in advance through experiments or the like. The activation of the device 42A may be determined. The generation amount of the reformed gas can be detected from the supply amounts of hydrocarbon fuel and air of the fuel supply means 52 and the air supply means 53. Further, the storage amount of the reformed gas can be detected using the generated amount, or can be detected using a sensor provided in the reformed gas storage tank 56. For example, a flow rate sensor that detects the amount of reformed gas flowing into the reformed gas storage tank 56 may be provided, and the amount of reformed gas stored may be detected from the integrated value of the amount of inflow. Further, a pressure sensor for detecting the internal pressure of the reformed gas storage tank 56 may be provided, and the amount of reformed gas stored may be estimated from the pressure value.

  In such an internal combustion engine 1, by performing such warm-up control before starting the engine, it becomes possible to immediately purify harmful components in the exhaust gas by the exhaust purification device 42A immediately after starting the engine.

  On the other hand, for example, the exhaust purification device 42A may already be activated in a situation such as at the time of restart, and in such a situation, it is not necessary to perform the warm-up control before starting the engine. In addition, the bed temperature of the exhaust purification catalyst may become lower than the activation temperature due to light load operation for a long time. In such a case, warm-up control should be performed again to suppress the deterioration of the emission performance. It is. On the other hand, if the warm-up control is continued, there is a risk that the bed temperature of the exhaust purification catalyst will rise to an excessive level and cause damage or the like.

  Therefore, in the internal combustion engine 1 of the first embodiment, it is preferable to control the execution period of the warm-up control for the exhaust purification device 42A as follows.

  For example, here, the warm-up control is executed when the bed temperature of the exhaust purification catalyst estimated from the detection value of the exhaust temperature sensor 43 is equal to or lower than a first predetermined value, and is warmed when the bed temperature is equal to or higher than the second predetermined value. The warm-up control function of the electronic control unit 70 is constructed to stop the machine control. As the first predetermined value, an activation temperature (for example, 350 ° C.) of the exhaust purification catalyst is set. On the other hand, as the second predetermined value, it can be assumed that the floor temperature of the exhaust purification catalyst decreases immediately after the warm-up control is stopped, so a temperature higher than the activation temperature (for example, 450 ° C.) is set.

  As a result, in the internal combustion engine 1, when the engine is cold such as when the engine is started (when the above-described warm-up control before starting the engine is performed, before the engine is started), the bed temperature of the exhaust purification catalyst is the first predetermined value. If it is below, the reformed gas is generated to perform warm-up control of the exhaust purification device 42A, and the exhaust purification device 42A is activated early.

  Further, in the internal combustion engine 1, when the bed temperature of the exhaust purification catalyst becomes equal to or higher than the second predetermined value, the warm-up control is stopped and the operation is switched to the operation with the hydrocarbon fuel. Thereafter, harmful components are generated by the combustion of the hydrocarbon-based fuel, but since the exhaust purification device 42A is activated here, the harmful components are purified by the exhaust purification device 42A.

  Further, in the internal combustion engine 1, when the bed temperature of the exhaust purification catalyst becomes equal to or lower than the first predetermined value due to a long light load operation or the like, the operation with the hydrocarbon fuel is changed to the operation with the reformed gas. Then, the warm-up control of the exhaust purification device 42A is executed again. Therefore, in the exhaust purification device 42A, the bed temperature of the exhaust purification catalyst rises to the activation temperature or higher and is activated again. Here, the first predetermined value may be set to a temperature (for example, 360 ° C.) that is slightly higher than the activation temperature of the exhaust purification catalyst, so that before the floor temperature of the exhaust purification catalyst falls below the activation temperature. Since warm-up control can be performed, the active state of the exhaust purification device 42A can be maintained, which is preferable.

  Thus, by setting the execution period of the warm-up control as described above, it is possible to keep the activated state of the exhaust purification device 42A while activating the exhaust purification device 42A, so that the good emission during the operation of the internal combustion engine 1 can be maintained. It becomes possible to continue to secure performance. In addition, the operation with the reformed gas reduces the generation of harmful components while deteriorating the fuel consumption rate, but at a certain time (when the bed temperature of the exhaust purification catalyst exceeds the second predetermined value). In addition, since the warm-up control is stopped and the operation is switched to the operation with the hydrocarbon-based fuel, it is possible to ensure good emission performance while suppressing the deterioration of the fuel consumption rate. Further, by stopping the warm-up control, it is possible to suppress overheating of the exhaust purification device 42A, and to prevent damage or the like.

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

  In the second embodiment, in the internal combustion engine 1 of the first embodiment described above, the exhaust purification device 42A is replaced with an exhaust purification device 42B shown below, and the capacity (per unit time) of the fuel reforming means 51 of the fuel reforming device 50 is changed. The capacity of the reformed gas that can be generated is smaller than that of the first embodiment.

The exhaust purification device 42B of the second embodiment is obtained by changing the exhaust purification means 421A included in the exhaust purification device 42A of the first embodiment to the exhaust purification means 421B. Specifically, the exhaust purification unit 421B includes the same fuel reforming catalyst as the fuel reforming catalyst 51b of the fuel reforming unit 51 on the inner wall surface of each reformed gas passage 421b in the exhaust purification unit 421A of the first embodiment. (For example, coating). In this exhaust gas control means 421B are disposed a fuel reforming catalyst on both sides and the plane of the flat sheet 421A ₁ facing the respective surfaces of the second corrugated sheet 421A ₃ waveforms.

  Here, in the second embodiment, it is assumed that the supply amounts of hydrocarbon fuel and air to the mixing portion 51a of the fuel reforming means 51 are the same as those in the first embodiment. In the internal combustion engine 1 of the second embodiment, a part of the mixture of the hydrocarbon fuel and air is reformed into reformed gas by the small volume fuel reforming means 51, and the reformed gas and the remaining gas are mixed. The unreformed hydrocarbon fuel and air mixture flows into the reformed gas passages 421b of the exhaust purification unit 421B.

At that time, in the exhaust purification unit 421B of the second embodiment, the high-temperature reformed gas that has flowed in is used for heat exchange with the exhaust purification catalyst in the exhaust gas passage 421a in the same manner as in the first embodiment. Increase the bed temperature of the purification catalyst. Further, in the exhaust gas purification means 421B of the second embodiment, since each reformed gas passage 421b is provided with a fuel reforming catalyst, the unreformed hydrocarbon fuel and air can be passed through the respective reformed gas passages 421b. The air-fuel mixture causes a reforming reaction to generate a reformed gas. For this reason, in this exhaust purification means 421B, the bed temperature of the exhaust purification catalyst is raised by the high-temperature reformed gas generated in each reformed gas passage 421b, and further, in each reformed gas passage 421b. The fuel reforming catalyst directly heats the flat foil 421A ₁ by the exothermic reaction during reforming, and raises the bed temperature of the exhaust purification catalyst.

  The calorific value of the exothermic reaction in each reformed gas passage 421b and the reformed gas generated thereby is larger than the calorific value of the reformed gas flowing in from the fuel reforming means 51. Therefore, according to the internal combustion engine 1 of the second embodiment, not only the same effects as in the first embodiment are exhibited, but also the heat exchange with the exhaust purification catalyst is performed with a larger amount of heat than that in the first embodiment. The exhaust gas purification device 42B can be activated earlier by raising the bed temperature to the activation temperature earlier. For this reason, in the internal combustion engine 1, it is possible to switch to combustion with the hydrocarbon-based fuel at an earlier stage, so that it is possible to realize further optimal combustion control according to desired operating conditions.

  In the second embodiment, the capacity of the fuel reforming means 51 is made smaller than that in the first embodiment (in other words, the heat capacity is made smaller than that in the first embodiment). Not only can the effect be obtained, but the input power during the initial heating of the fuel reforming catalyst 51b can also be reduced.

  The internal combustion engine 1 of the second embodiment may apply the fuel reforming means 51 having the same capacity as that of the first embodiment. In such a case, the supply amounts of the hydrocarbon-based fuel and air to the mixing unit 51a are set. More than in Example 1.

  By the way, also in the internal combustion engine 1 of the second embodiment, the warm-up control before the engine start described in the first embodiment may be executed, and the exhaust period is set by setting the same execution period as in the first embodiment. You may perform warm-up control of the purification apparatus 42B.

  In addition, hydrocarbon-based fuel and air (oxygen) are supplied to the reformed gas passages 421b of the second embodiment without supplying the reformed gas, and the reforming reaction in the fuel reforming catalyst on the passages. It is also possible to activate the exhaust purification catalyst early using only this.

  Next, a third embodiment of the internal combustion engine according to the present invention will be described with reference to FIGS.

  In the third embodiment, in the internal combustion engine 1 of the first embodiment described above, the exhaust purification device 42A is replaced with an exhaust purification device 42C shown below.

  As described above, not all hydrocarbon fuels may be completely reformed in the fuel reforming means 51 of the fuel reformer 50. In such a case, the unreformed hydrocarbon fuel is not converted into the combustion chamber. It will burn and generate harmful components. Therefore, even in the internal combustion engine 1 of the first embodiment described above, until the exhaust purification device 42A is activated, the harmful components cannot be purified by the exhaust purification device 42A and are released to the atmosphere. .

  Further, in the internal combustion engine 1 of the first embodiment, if the warm-up control before starting the engine is executed, the harmful components can be purified by the exhaust purification device 42A, but compared with the reformed gas (hydrogen gas). If a large amount of unreformed fuel with inferior flammability and narrow ignition limit is generated, the concentration of hydrogen gas in the air-fuel mixture sucked into the respective combustion chambers decreases, resulting in poor combustion such as misfire, Torque fluctuations can occur.

  Therefore, in the internal combustion engine 1 of the third embodiment, the flow rate of unreformed fuel (hydrocarbon fuel) is not reduced upstream of the combustion chambers of the first to fourth cylinders 11a to 11d. A reforming fuel flow rate adjusting means is provided. In the third embodiment, the unreformed fuel flow rate adjusting means is provided in the exhaust purification device 42C.

  The exhaust purification device 42C according to the third embodiment is obtained by changing the exhaust purification means 421A included in the exhaust purification device 42A according to the first embodiment to the exhaust purification means 421C. A fuel flow control means is provided. Specifically, the exhaust gas purification unit 421C includes an HC adsorbent as an unreformed fuel flow rate adjustment unit disposed on the inner wall surface of each reformed gas passage 421b in the exhaust gas purification unit 421A of the first embodiment (for example, coating) ). As the HC adsorbent, zeolite or the like that can adsorb unreformed fuel (hydrocarbon fuel) while allowing the reformed gas to permeate is used.

  Thus, the reformed gas discharged from the fuel reforming means 51 passes through the reformed gas passage 421b and is sent to the combustion chamber while warming the exhaust purification catalyst of the exhaust purification means 421C.

  On the other hand, the unreformed fuel discharged from the fuel reforming means 51 is adsorbed by the HC adsorbent in the reformed gas passage 421b. For this reason, in the internal combustion engine 1 of the third embodiment, unreformed fuel is not sucked into the respective combustion chambers, so that it is possible to ensure good emission performance even before the exhaust purification device 42C is activated. In addition, it is possible to prevent torque fluctuation by suppressing combustion failure such as misfire.

  The adsorbed unreformed fuel is gradually desorbed from the HC adsorbent that has reached a predetermined temperature as the temperature of the exhaust purification unit 421C rises, and is gradually sent to the combustion chamber. For this reason, in the internal combustion engine 1 of the third embodiment, even if unreformed fuel is sucked into the combustion chamber, the hydrogen gas concentration in the air-fuel mixture does not extremely decrease, so that poor combustion such as misfire is suppressed. Torque fluctuation can be prevented. Furthermore, in the internal combustion engine 1, the desorbed unreformed fuel is burned in the respective combustion chambers to generate harmful components. When such a desorption phenomenon occurs, the exhaust purification catalyst has already reached the activation temperature. Sufficient time has passed and the harmful components can be purified by the exhaust purification catalyst, so that the emission performance is not deteriorated.

  As described above, according to the internal combustion engine 1 of the third embodiment, not only the same effects as those of the first embodiment can be obtained, but also good emission while suppressing poor combustion such as misfire caused by unreformed fuel. Performance can be ensured.

  By the way, also in the internal combustion engine 1 of the third embodiment, the warm-up control before the engine start described in the first embodiment may be executed, and the exhaust period is set by setting the same execution period as in the first embodiment. You may perform warm-up control of the purification apparatus 42C.

  Next, a fourth embodiment of the internal combustion engine according to the present invention will be described with reference to FIGS. 1, 2, and 4 to 6. FIG.

  The fourth embodiment is obtained by replacing the exhaust purification device 42A with the exhaust purification device 42D shown below in the internal combustion engine 1 of the first embodiment described above.

  The exhaust purification device 42D of the fourth embodiment is configured to provide an exhaust purification means 421A in the exhaust purification device 42A of the first embodiment in order to simultaneously realize the effects of the exhaust purification devices 42B and 42C of the second and third embodiments. 6 is changed to the exhaust purification means 421D shown in FIG. Specifically, the exhaust purification unit 421D is implemented on the reformed gas inlet side (upstream side with respect to the flow direction of the reformed gas) on the inner wall surface of each reformed gas passage 421b in the exhaust purification unit 421A of the first embodiment. The same fuel reforming catalyst 44 as in Example 2 is disposed (for example, coated), and the same HC adsorbent as in Example 3 is provided on the reformed gas outlet side (downstream with respect to the flow direction of the reformed gas) on the inner wall surface. The unreformed fuel flow rate adjusting means 45 such as, for example, is disposed (for example, coated).

  Therefore, in the fourth embodiment, as in the second embodiment, the capacity of the fuel reforming means 51 is reduced or the amount of hydrocarbon fuel and air supplied to the mixing section 51a is increased.

  According to the internal combustion engine 1 of the fourth embodiment, the reformed gas generated by the fuel reforming means 51 passes through the respective reformed gas passages 421b of the exhaust purification means 421D to increase the bed temperature of the exhaust purification catalyst. Let

  On the other hand, in the internal combustion engine 1 of the fourth embodiment, the mixture of unreformed fuel and air remaining without being reformed by the fuel reforming means 51 also flows into each reformed gas passage 421b. In each reformed gas passage 421b, the air-fuel mixture first undergoes a reforming reaction in the upstream fuel reforming catalyst 44, and, as in the second embodiment, the heat of the reformed gas generated thereby. And the bed temperature of the exhaust purification catalyst is raised by the exothermic reaction during reforming. Further, in each reformed gas passage 421b, when there is unreformed fuel that could not be reformed even by the reforming reaction on the upstream side, the unreformed fuel is converted to the unreformed fuel on the downstream side. The flow rate adjusting means (HC adsorbent) 45 is adsorbed.

  Therefore, according to the internal combustion engine 1 of the fourth embodiment, the effects of the second and third embodiments can be obtained, so that the exhaust purification device 42D can be activated earlier, and the unreformed fuel can be obtained. Good emission performance can be ensured while suppressing poor combustion such as misfire.

  By the way, also in the internal combustion engine 1 of the fourth embodiment, the warm-up control before the engine start described in the first embodiment may be executed, and the exhaust period is set by setting the same execution period as in the first embodiment. You may perform warm-up control of the purification apparatus 42D.

  Next, a fifth embodiment of the internal combustion engine according to the present invention will be described with reference to FIGS. 1, 2, 4, 5, and 7. FIG.

  In the fifth embodiment, in the internal combustion engines 1 of the first to fourth embodiments described above, the exhaust purification devices 42A, 42B, 42C, and 42D are replaced with the exhaust purification devices 42E shown below, and the exhaust purification devices 42E are used. The positional relationship between the fuel reformer 50 and the fuel reformer 50 is changed as shown in FIG. Therefore, any one of the exhaust purification unit 421A, the exhaust purification unit 421B, the exhaust purification unit 421C, or the exhaust purification unit 421D of each of the first to fourth examples is provided in the exhaust purification device 42E of the fifth embodiment. ing.

  Generally, the capacity of the exhaust purification catalyst of the exhaust purification device is set so that harmful components therein are reliably purified even when the maximum amount of exhaust gas is discharged from all the combustion chambers. On the other hand, during the period from the start of the engine to the end of the warm-up operation, the amount of exhaust gas discharged is smaller than the maximum amount, and it is sufficient that the harmful components in the exhaust gas with the small amount of exhaust can be purified. Therefore, in the meantime, it is not always necessary that the entire exhaust purification catalyst reaches the activation temperature.

  Thus, in the fifth embodiment, the exhaust gas purification device can perform warm-up control for a part of the exhaust gas purification catalyst corresponding to the exhaust gas emission amount from the time of starting the engine to the end of the warm-up operation. The positional relationship between 42E and the fuel reformer 50 is set.

  Here, when the bed temperature of the exhaust purification catalyst upstream of the exhaust gas flow direction in the exhaust purification means 421A (exhaust purification means 421B, 421C, 421D) is increased, the exhaust gas passes therethrough. However, the temperature rises and the exhaust gas purification catalyst on the downstream side can be warmed by the exhaust gas. In addition, by warming the exhaust purification catalyst on the upstream side, the exhaust gas discharged from the combustion chamber can be further heated at a high temperature, and the temperature rise of the entire exhaust purification catalyst can be accelerated.

  Therefore, in the fifth embodiment, the positional relationship between the exhaust purification device 42E and the fuel reforming device 50 is set so that the upstream exhaust purification catalyst is activated first. Specifically, as shown in FIG. 7, the upstream end of the exhaust purification unit 421A (exhaust purification unit 421B, 421C, 421D) is disposed between the fuel reforming unit 51 and the reformed gas supply path 54, The fuel reforming means 51 and the reformed gas supply path 54 are communicated with each other through respective reformed gas passages 421b at the upstream end.

  In the internal combustion engine 1 of the fifth embodiment, the reformed gas generated by the fuel reforming means 51 is the reformed gas at the upstream end of the exhaust purification means 421A (exhaust purification means 421B, 421C, 421D). It flows into the passage 421b. Here, in the case of the exhaust purification device 42E having the exhaust purification means 421B and 421D, mixing is performed so that unreformed fuel is discharged together with the reformed gas from the fuel reforming means 51, as in the second and fourth embodiments. The supply amounts of hydrocarbon fuel and air to the section 51a are adjusted.

Thus, the exhaust gas purification device 421A (the exhaust gas control means 421B, 421C, 421D) in the exhaust gas purification of the end portion of the upstream side heat of the high-temperature reformed gas through a flat foil 421A ₁ of each exhaust gas passage 421a It is transmitted to the catalyst and raises the bed temperature of the exhaust purification catalyst. Further, in the case of the exhaust purification device 42E having the exhaust purification means 421B and 421D, as in the second and fourth embodiments, the fuel reforming catalyst in each reformed gas passage 421b at the upstream end thereof is not modified. The mixture of the quality fuel and air causes a reforming reaction, and further raises the bed temperature of the exhaust purification catalyst at the upstream end thereof.

  Here, in the fifth embodiment, the amount of the exhaust purification catalyst warmed by the reformed gas (that is, the heat capacity) is smaller than each of the first to fourth embodiments described above, and therefore the same amount as each of the first to fourth embodiments. If the reformed gas is supplied to the exhaust purification means 421A (exhaust purification means 421B, 421C, 421D), the temperature of the exhaust purification catalyst at the upstream end can be raised more quickly.

  In the case of the exhaust purification device 42E having the exhaust purification means 421C and 421D, as in the third and fourth embodiments, the unreformed fuel flow rate adjustment means (in the reformed gas passage 421b at the upstream end thereof ( Unreformed fuel is adsorbed to the HC adsorbent.

  By the way, in this exhaust purification means 421A (exhaust purification means 421B, 421C, 421D), the temperature of the exhaust gas flowing through the upstream end of each exhaust gas passage 421a as the floor temperature of the exhaust purification catalyst increases. To rise. The temperature rise of the exhaust gas includes a heat transfer from the exhaust purification catalyst and a reaction temperature at the time of the purification reaction. For this reason, in the exhaust gas purification means 421A (exhaust gas purification means 421B, 421C, 421D), when the exhaust gas whose temperature has increased flows to the downstream side of each exhaust gas passage 421a, each exhaust gas on the downstream side thereof. The exhaust purification catalyst in the passage 421a is also warmed.

  Therefore, in the internal combustion engine 1 of the fifth embodiment, a part of the exhaust purification catalyst corresponding to the emission amount of a small amount of exhaust gas is activated first, and then the remaining exhaust purification catalyst is activated. In particular, since the exhaust gas purification catalyst on the downstream side is activated after activating the exhaust gas purification catalyst on the upstream side, the reformed gas generated by the fuel reforming means 51 and the exhaust gas from each combustion chamber are exhausted. The entire exhaust purification catalyst is activated early without wasting the amount of heat of each exhaust gas. Therefore, during the period from the start of the engine to the end of the warm-up operation of the internal combustion engine 1, harmful components in a small amount of exhaust gas can be purified only by the upstream side exhaust purification catalyst as described above. Further, in the internal combustion engine 1 of the fifth embodiment, since the entire exhaust purification catalyst can be activated at an early stage, naturally, after the warm-up operation ends, before the warm-up operation ends. In addition, harmful components can be purified even if the exhaust gas emission increases due to vehicle acceleration or the like.

  Here, in the fifth embodiment, the exhaust gas purification means in which any one of the exhaust gas purification means 421A, the exhaust gas purification means 421B, the exhaust gas purification means 421C, or the exhaust gas purification means 421D of the above-described first to fourth embodiments is provided. The device 42E is illustrated. However, the exhaust gas purification means 421B, the exhaust gas purification means 421C, and the exhaust gas purification means 421D among them are a fuel reforming catalyst or an unreformed fuel flow rate control that does not have any effect unless the reformed gas passes through. Means (HC adsorbent) are also disposed in the respective reformed gas passages 421b on the downstream side. Therefore, regarding the exhaust purification device 42E of the fifth embodiment, instead of the exhaust purification unit 421B, the exhaust purification unit 421C, or the exhaust purification unit 421D, the fuel reforming catalyst in the reformed gas passage 421b on the downstream side from these, It is preferable to replace the exhaust gas purifying means 421E shown in FIG. 7 with the unreformed fuel flow rate adjusting means (HC adsorbent) removed.

Further, in the fifth embodiment, the exhaust gas purification means 421A, the exhaust gas purification means 421B, the exhaust gas purification means 421C, the exhaust gas purification means 421D, or the exhaust gas purification means 421E, in which the exhaust gas passage 421a and the reformed gas passage 421b are all integrated. Exemplified is an exhaust purification device 42E provided with However, in the positional relationship between the exhaust purification device 42E and the fuel reforming device 50 of the fifth embodiment, the exhaust purification means 421A, 421B, 421C, 421D, 421E is modified to the downstream side where the reformed gas does not pass. There is no point in providing the quality gas passage 421b. Further, if the whole is integrated, the heat on the upstream side is transferred to the downstream side through a structure such as the flat foil 421A ₁ , which may hinder early activation of the upstream side exhaust purification catalyst. There is.

Therefore, in the internal combustion engine 1 of the fifth embodiment, it is preferable to replace such an exhaust purification device 42E with an exhaust purification device 42F shown in FIG. The exhaust purification device 42F includes an exhaust purification unit 421F having a divided structure including a first exhaust purification unit 421F _{1 at} the front stage and a second exhaust purification unit 421F _{2 at the} rear stage.

Here, the first exhaust purification means 421F ₁ is a cross-flow type exhaust purification catalyst carrier having the same configuration as the exhaust purification means 421A, the exhaust purification means 421B, the exhaust purification means 421C or the exhaust purification means 421D described above. Therefore, it is disposed on the upstream side through which the reformed gas passes. The second exhaust purification means 421F ₂ is an exhaust purification catalyst carrier in which only the exhaust gas passage 421a is formed in a honeycomb shape, and is disposed on the downstream side.

  Then, by replacing the exhaust gas purification device 42F with the exhaust gas purification device 42F, the internal combustion engine 1 can prevent the escape of heat from the upstream to the downstream as in the above-described exhaust gas purification device 42E. The bed temperature of the upstream side exhaust purification catalyst can be raised earlier than in this case, so that the entire exhaust purification catalyst can be activated more quickly.

  By the way, also in the internal combustion engine 1 of the fifth embodiment, the warm-up control before the engine start described in the first embodiment may be executed, and the exhaust period is set with the same execution period as that in the first embodiment. The warm-up control of the purification device 42E (or the exhaust purification device 42F) may be executed.

  Next, a sixth embodiment of the internal combustion engine according to the present invention will be described with reference to FIG.

  The sixth embodiment is configured to activate the exhaust purification catalyst earlier in the internal combustion engine 1 of each of the first to fifth embodiments described above.

Specifically, in the sixth embodiment, in the internal combustion engine 1 of each of the first to fifth embodiments, the fuel reforming means 51 and the exhaust purification means 421A (exhaust purification means 421B, exhaust purification means 421C, exhaust purification means 421D). , An oxygen supply device for supplying oxygen between the exhaust purification unit 421E and the first exhaust purification unit 421F ₁ ) is provided.

  For example, as an oxygen supply apparatus according to the sixth embodiment, as shown in FIG. 9, an air supply passage 57a that guides air to the reformed gas discharge portion of the fuel reforming means 51 and an on-off valve that opens and closes the air supply passage 57a. 57b is used. Here, the air supply passage 57 a takes in air from the air supply path 53 b between the pump 53 a and the air supply amount adjustment valve 53 c in the air supply means 53, and leads to the reformed gas discharge portion of the fuel reforming means 51. Send it out. The on-off valve 57b is assumed to be closed in an initial state such as before the engine is started.

  In the internal combustion engine 1 of the sixth embodiment, when the electronic control unit 70 starts generating reformed gas by the fuel reforming means 51 (that is, when the fuel reforming unit 50 is started), the electronic control unit 70 opens the on-off valve 57b to supply air from the air supply passage 57a to the reformed gas discharge portion of the fuel reforming means 51.

  Here, the generated reformed gas is in a high temperature state (approximately 950 ° C.) as described above, and the reformed gas contains hydrogen gas with good ignitability at high temperature. When air is supplied, a part of the reformed gas is combusted using the hydrogen gas as an ignition point, and the remaining reformed gas is further heated.

Therefore, in the internal combustion engine 1 of the sixth embodiment, the reformed gas further heated at the reformed gas discharge portion of the fuel reforming means 51 is exhausted purifying means 421A (exhaust purifying means 421B, exhaust purifying means 421C, The exhaust gas purification means 421D, the exhaust gas purification means 421E, and the first exhaust gas purification means 421F ₁ ) flow into the respective reformed gas passages 421b. Therefore, according to the internal combustion engine 1 of the sixth embodiment, the reformed gas having a temperature higher than those of the first to fifth embodiments described above is passed through the respective reformed gas passages 421b. Compared to 5, the exhaust purification catalyst can be activated earlier.

  As described above, the internal combustion engine according to the present invention is useful for a technique for quickly activating an exhaust purification catalyst using a reformed gas.

It is a figure which shows the whole structure in Examples 1-5 of the internal combustion engine which concerns on this invention. It is a figure which shows an example of the fuel reforming apparatus of the internal combustion engine which concerns on this invention. It is a figure shown about the exhaust gas purification apparatus and fuel reformer of Examples 1-3. It is a whole view explaining the structure of the exhaust gas purification means of Examples 1-4. It is a components figure explaining the structure of the exhaust gas purification means of Examples 1-4. It is a figure shown about the exhaust gas purification device and fuel reformer of Example 4. It is a figure shown about the exhaust gas purification device and fuel reformer of Example 5. FIG. 10 is a diagram illustrating an exhaust purification device and a fuel reforming device having different configurations according to a fifth embodiment. It is a figure which shows the whole structure in Example 6 of the internal combustion engine which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 20 Intake path 27 Intake manifold 40 Exhaust path 42, 42A, 42B, 42C, 42D, 42E, 42F Exhaust purification device 43 Exhaust temperature sensor 50 Fuel reforming device 51 Fuel reforming means 51b Fuel reforming catalyst 54 Reforming Gas supply passages 55a to 55d First to fourth reformed gas supply devices 56 Reformed gas storage tank 57a Air supply passage 57b On-off valve 70 Electronic control device 421, 421A, 421B, 421C, 421D, 421E, 421F Exhaust gas purification means 421F ₁ first exhaust purification means 421F ₂ second exhaust purification means 421a exhaust gas passage 421b reformed gas passage

Claims (5)

In an internal combustion engine operable to generate a reformed gas by causing an exothermic reaction of a predetermined fuel with a fuel reforming catalyst of a fuel reformer, and using the reformed gas as a fuel,
The exhaust purification device on the exhaust path is provided with an exhaust purification catalyst that can exchange heat with the reformed gas supplied from the fuel reforming device and / or the fuel reforming catalyst provided in the exhaust purification device. An internal combustion engine characterized by that.   2. The internal combustion engine according to claim 1, wherein the exhaust purification device includes an exhaust purification means in which an exhaust gas passage having the exhaust purification catalyst and a reformed gas passage adjacent to the exhaust gas passage are formed.   A control means for controlling the fuel reforming device so as to generate a fuel reforming catalyst for the exhaust gas purification device at least partially on the reformed gas passage and to generate unreformed fuel together with the reformed gas is provided. The internal combustion engine according to claim 2.   A reformed gas storage tank for storing the reformed gas after heat exchange, and a control means for starting the engine after a predetermined amount of the reformed gas is stored in the reformed gas storage tank are provided. An internal combustion engine according to claim 1, 2, or 3.   The internal combustion engine according to claim 1, 2, 3, or 4, further comprising an oxygen supply device for supplying oxygen to the reformed gas before heat exchange.

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