JP2007332891A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase a comprehensive fuel calorific amount as a result of modifying autoexhaust (combustion gases) to make use of the modified gases obtained as fuel. <P>SOLUTION: Among a plurality of cylinders, a cylinder injection valve 54 is provided in a modifying cylinder 42 equipped with an autoexhaust modifying function and then the modified gases are supplied from an exhaust side of the modifying cylinder 42 to intake sides of cylinders 44 other than the modifying cylinder 42. In the modifying cylinder 42, after having combusted fuel supplied in the modifying cylinder and an air-fuel mixture containing air, during a period of time elapsed till emissions of the combustion gases from an inside of the cylinder are completed, a modifying fuel from an ent-cylinder injection valve 54 is subjected to injection. Thereby, an air-fuel mixture of a combustion gas (exhaust gases) and fuel is produced to practice a modifying reaction. Consequently, a calorific quantity of the combustion gases within the cylinder can be directly made use of for the modifying reaction that is an endoergic reaction, so that high-efficiency modification becomes possible, thus contributing an improvement in thermal efficiency of an internal combustion engine. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an internal combustion engine having a fuel reforming function.

  From the viewpoint of improving the combustion efficiency of an internal combustion engine, etc., an internal combustion engine has been proposed in which hydrogen gas obtained by reforming fuel is supplied to a combustion chamber together with the fuel and burned. For example, in Patent Document 1 below, fuel and water are vaporized by an evaporator, then sent to a reformer for reforming, and hydrogen gas is taken out as reformed gas by passing through a hydrogen permeable membrane. A configuration is employed in which gas is supplied to the intake port of the cylinder. Because hydrogen gas is more reactive than other combustible gases, using hydrogen as part of the fuel can expand the lean burn limit, stabilize combustion and prevent misfires, and at the same time into exhaust gas It is possible to reduce the contained hydrocarbon.

  Non-Patent Documents 1 and 2 were obtained in a multi-cylinder internal combustion engine, in which a rich mixture was burned in one of the multi-cylinders, and exhaust gas from this cylinder was supplied to the catalyst. It has been proposed to perform lean combustion by distributing CO and hydrogen to other cylinders.

  In Patent Document 2, it is proposed that the reformed gas obtained by reforming the exhaust gas is circulated to the intake side of the cylinder, and an exhaust gas reforming conduit is branched from the exhaust pipe. The exhaust gas is reformed by mixing the fuel with the exhaust gas in the conduit for use.

JP 2002-339772 A JP 2006-37879 A David P. Meyers, John T. Kubesh, `` The Hybrid Rich-burn / lean-burn engine '', ASME 1994, ICE-Vol. 24, Natural Gas and Alternative Fuels for Engines Jack A. Smith, Dan Podnar, David P. Meyers, "The Hybrid Rich-Burn / Lean Burn Engine, Part 2", ASME 1996, ICE-Vol.27-4, 1996 Fall Technical Conference Volume 4

  In order to reform the fuel as in Patent Document 1, a heat exchanger for vaporizing the fuel and water is required. Further, since reforming with fuel and water becomes an endothermic reaction, a heat exchanger or the like for transferring the heat of the exhaust gas to the reformer is required, which leads to complication and enlargement of the engine.

  Next, in Patent Document 2 and Non-Patent Documents 1 and 2, the reforming of exhaust gas disclosed therein is also an endothermic reaction. Therefore, in Patent Document 2, a heat exchange mechanism for obtaining heat necessary for reforming from exhaust gas is provided. Non-Patent Documents 1 and 2 do not particularly disclose a heat exchange mechanism. However, obtaining heat necessary for an endothermic reaction is essential in principle, and a heat exchanger, a heater, and the like are required. Therefore, as in the case of Patent Document 1, the engine is complicated and large.

  Further, the efficiency of the heat exchanger is at most 70 to 80%, and there is a limit to the heat utilization of the exhaust gas. On the other hand, the reforming of the hydrocarbon fuel has a higher reforming rate at a higher temperature. Therefore, the efficiency of the heat exchanger directly affects the engine performance, which hinders the improvement of the engine performance.

  Further, the reforming mechanism (reforming catalyst, evaporator, etc.) is provided on the exhaust pipe side as described above, and is separated from the cylinder in which combustion is performed. Therefore, it is inevitable that the temperature decreases until the exhaust gas from the cylinder reaches the reforming section, and there is a problem that it is difficult to obtain an optimal amount of heat from the exhaust gas for reforming.

  The present invention is an internal combustion engine having a plurality of cylinders, wherein at least one of the plurality of cylinders is a reforming cylinder having an exhaust gas reforming function, and includes an in-cylinder injection valve, Among the plurality of cylinders, at least a cylinder other than the reforming cylinder is provided with reformed gas supply means for supplying reformed gas through an exhaust pipe of the reforming cylinder, and the reforming cylinder includes The fuel for reforming is injected into the cylinder from the in-cylinder injection valve in the period from the combustion of the air-fuel mixture containing fuel and air supplied into the cylinder to the completion of exhaust of the combustion gas from the cylinder. Thus, a mixed gas of the exhaust gas and the reforming fuel is prepared.

  In another aspect of the present invention, in each of the plurality of cylinders, a mixture of fuel and air is supplied to perform combustion, and after the combustion, the reforming fuel is cylindered only in the reforming cylinder. Internally injected, a mixed gas of the exhaust gas and fuel is created.

  In another aspect of the present invention, the fuel gas in the reforming cylinder after injecting the reforming fuel after burning the air-fuel mixture containing the fuel and air in the reforming cylinder. Is controlled to have an equivalent ratio of 1 or more.

  In another aspect of the present invention, in the internal combustion engine, the exhaust gas equivalence ratio is controlled to be 1 at least in cylinders other than the reforming cylinder.

  In another aspect of the present invention, a reforming catalyst for advancing a reforming reaction of the mixed gas of the exhaust gas and the reforming fuel is provided in the exhaust pipe of the reforming cylinder.

  In the present invention, exhaust gas (combustion gas) is reformed, and the resulting reformed gas is used as fuel, so that the total fuel heating value can be increased. Therefore, further improvement in fuel consumption can be achieved. Further, the obtained reformed gas contains a large amount of hydrogen, and by using such a reformed gas, combustion in the cylinder is quickly performed. Moreover, since the octane number of hydrogen and carbon monoxide contained in the reformed gas is high, the compression ratio can be increased, and the thermal efficiency of the internal combustion engine can be improved.

  Further, the reformed gas can be obtained from the exhaust gas (combustion gas), and this reformed gas is supplied to the intake side of the cylinder of the internal combustion engine, so that the working gas volume of the internal combustion engine increases. Therefore, the gas exchange loss at the partial load can be reduced.

  According to the present invention, the fuel mixture for fuel and air is combusted and the fuel for reforming is injected in the cylinder before the combustion gas is exhausted. It can be used very effectively for the reforming reaction of combustion gas. Further, as the reforming fuel, the same fuel as the fuel of the air-fuel mixture can be adopted. Further, since the reforming fuel is injected in the cylinder, the combustion gas and the fuel are agitated and mixed in the cylinder due to the expansion of the combustion gas and the accompanying movement of the piston. The combustion gas (exhaust gas) and the reforming fuel are also mixed by high-speed flow and turbulence when the exhaust gas is discharged from the exhaust valve of the cylinder. Therefore, very high reforming efficiency can be realized.

  Further, the configuration of a heat exchanger for obtaining heat necessary for reforming from exhaust gas and an evaporator for vaporizing reforming fuel can be omitted, which is very advantageous for downsizing of an internal combustion engine. It becomes.

  Further, in the reforming cylinder, an air-fuel mixture of fuel and air is burned, and then additional fuel injection for reforming is executed. Before the reforming, torque is obtained by combustion of the air-fuel mixture. Therefore, the thermal efficiency of the internal combustion engine can be improved accordingly.

  Further, in the present invention, when a multi-cylinder internal combustion engine is employed, and some of the cylinders are employed as reforming cylinders, and the reformed gas obtained here is supplied to the remaining cylinders, A mechanism for distributing the gas and the gas exhausted from the internal combustion engine is unnecessary, and the configuration can be simplified.

    Hereinafter, embodiments of the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

  FIG. 1 shows an outline of an internal combustion engine according to this embodiment. The internal combustion engine 100 according to the present embodiment employs a so-called multi-cylinder engine having a plurality of cylinders, and at least one of the plurality of cylinders 40 is used as the reforming cylinder 42 having the in-cylinder injection valve 54. The reformed gas obtained in the reforming cylinder 42 is supplied to the other cylinders 44 and used in combination with fuel. Further, the reforming cylinder 42 does not only perform reforming, but combusts a mixture of fuel such as gasoline and air in the same manner as the other cylinders 44. After combustion, under the control of the engine control unit (ECU) 200 or the like, fuel for reforming is supplied from the in-cylinder injection valve 54 until all the combustion gas is exhausted from the cylinder (between the expansion stroke and the exhaust stroke). It injects to form a mixed gas of combustion gas and reforming fuel. Although details will be described later, the reforming is an endothermic reaction, and the heat necessary for the reaction can be utilized by the heat of the combustion gas, and the reforming reaction can be performed in the cylinder.

  A reforming catalyst 62 is provided in the vicinity of the exhaust port of the reforming cylinder 42, and exhaust gas discharged from the reforming cylinder 42 (obtained by a mixture gas of combustion gas and reforming fuel and a reforming reaction). The reformed gas) flows into the reforming catalyst 62. Although the reforming catalyst 62 can be omitted, the reforming efficiency is improved by providing it on the exhaust side. This reforming catalyst 62 has a function of executing a reforming reaction from a mixed gas of exhaust gas and fuel, and also has a function of further advancing the reforming reaction started in the cylinder. The fuel is decomposed, and the chemical equilibrium of the reforming reaction is advanced in the direction of reformed gas generation.

A gas containing a large amount of CO and H ₂ (reformed gas) flows out from the reforming catalyst 62, and the obtained reformed gas is supplied to the cooler 66 through the exhaust pipe 60, cooled, and then reformed. The quality gas supply means 52 supplies at least a normal cylinder 44 other than the reforming cylinder 42 among the plurality of cylinders 40.

  As shown in FIG. 1, the reformed gas supply means 52 includes a reformed gas nozzle 53 provided at each intake port, with the reformed gas supply pipe 64 communicating with the intake port of each cylinder 44. In this case, the reformed gas discharged to the exhaust pipe 60 through the exhaust stroke of the reforming cylinder 42 and output to the reformed gas supply pipe 64 through the reforming catalyst 62 and the cooler 66 is automatically supplied to the reforming cylinder 42. It will be supplied to the intake pipe 30. In order to supply the reformed gas evenly to the intake pipes 30, in FIG. 1, a common reformed gas storage part (reformed gas gallery) 51 is provided for all the intake pipes 30 for the three cylinders. Then, the reformed gas is supplied from the accommodating portion 51 to each intake port of the cylinder 44 through each nozzle 53. A flow rate adjusting valve may be provided in the connecting path between the exhaust pipe 60 of the reforming cylinder and the intake pipe 30 of the cylinder 44, specifically, in the reformed gas storage unit 51 or in the reformed gas supply pipe 64. In addition, the amount of reformed gas supplied to each intake port can be controlled as necessary by this adjusting valve. The supply of the reformed gas to the intake side of the cylinder 44 is not limited to the nozzle 53 as described above, and a reformed gas injection valve may be provided. By adopting the gas injection valve, it is possible to accurately control the injection timing of the reformed gas and the like. Each cylinder 44 may be provided with an in-cylinder injection valve, and the reformed gas may be supplied into the cylinder from the in-cylinder injection valve with an appropriate pressure.

  Further, the intake pipe 10 of the reforming cylinder 42 and the other intake pipe 30 of the normal cylinder 44 are respectively provided with fuel injection valves 50 for injecting fuel such as gasoline near the intake ports. . The fuel pumped from the fuel tank 20 by the low-pressure pump 22 is injected from the injection valve 50 to the intake port. However, it is also possible to directly inject fuel into each cylinder by using an in-cylinder injection valve. It is.

  The intake pipe 30 of the cylinders 44 other than the reforming cylinder 42 is provided with a throttle valve 32 for commonly controlling the air supply amount to each cylinder 44. A throttle valve 12 for controlling the air supply to the reforming cylinder 42 is provided independently of the throttle valve 32. A sensor for measuring the flow rate of air passing through the throttle is attached around the throttle valves 32 and 12.

An exhaust pipe 70 of a normal cylinder 44 other than the reforming cylinder 42 is provided with an exhaust purification catalyst 72 using a three-way catalyst for purifying exhaust gas. When a three-way catalyst is used as the exhaust purification catalyst 72, in order to ensure that the purification process can be executed with this three-way catalyst, the stoichiometry that allows the exhaust gas exhausted from the cylinder 44 to be processed by the three-way catalyst. It is preferable that the ratio, that is, the equivalent ratio is 1. In this case, as shown in FIG. 1, an O ₂ sensor 74 is provided in the vicinity of the collection portion of the exhaust pipe 70 of each cylinder 44 to detect the amount of oxygen contained in the exhaust gas, and the engine control unit 200 detects the detected value. It is preferable to control the opening degree of the throttle valve 32 and the injection amount from the fuel injection valve 50 according to the above.

  Hereinafter, the configuration and operation of the internal combustion engine of the present embodiment will be described in more detail.

  The internal combustion engine 100 of this embodiment is a multi-cylinder engine, but in the example of FIG. 1, it is a four-cylinder row type engine composed of cylinder numbers # 1, # 2, # 3, and # 4. Each cylinder is provided with two intake valves 46 and two exhaust valves 48 at the upper part of the cylinder (cylinder head). The valves are opened and closed by a cam that rotates in half rotation in synchronization with the crankshaft. Is supposed to do. An ignition plug 45 is provided in the approximate center of the cylinder head, and an injection valve 50 for injecting fuel (gasoline) as described above is provided at the intake port of each cylinder. Further, of the four cylinders, three cylinders # 2, # 3, and # 4 are normal cylinders 44 other than the above-described reforming cylinders, and their exhaust ports communicate with the exhaust purification catalyst 72. Is discharged to the atmosphere through a silencer.

  The # 1 cylinder is a reforming cylinder 42 provided with an in-cylinder injection valve 54 capable of injecting fuel for reforming into the cylinder. The exhaust pipe 60 of this # 1 cylinder is connected to the exhaust pipe 70 of another cylinder. Are not communicated but are led to the intake side by a pipe 64 and communicated to the intake pipes 30 of # 2, # 3, and # 4.

  First, the operations of the # 2, # 3, and # 4 cylinders, that is, the normal cylinders 44 other than the reforming cylinder 42 are shown. The engine control unit 200 calculates the fuel and air amount to be sucked into the cylinder according to the engine load, determines the fuel injection amount and the air amount according to the result, and adjusts the throttle valve 32. The deviation between the calculated value and the actual supply amount is adjusted while measuring the air flow rate in the valve 32. In these cylinders 44, when the intake valve 46 is opened, the piston is lowered by the rotation of the crankshaft, and the adjusted fuel and air are sucked into the cylinders to form a combustible air-fuel mixture. When the intake valve 46 is closed, the piston rises and compresses the fuel / air mixture.

  The air-fuel mixture is ignited by the spark plug 45 near the top dead center, and the air-fuel mixture is combusted. As a result, the pressure in the cylinder rapidly increases, and the piston is pushed down to generate torque. When the crank rotates and the piston rises, the exhaust valve 48 is opened to push the combustion gas to the exhaust port. The combustion gas in the exhaust port is purified by the exhaust purification catalyst 72 and then released into the atmosphere through the silencer. The above operation is the same as that of a general engine (a gasoline engine when gasoline is used as fuel).

  Next, the operation of the # 1 cylinder (reforming cylinder 42) will be described. Steps # 2 and # 3 above are performed until the air amount is adjusted by the throttle valve 12, the fuel is adjusted by the fuel injection valve 50, the air and fuel are sucked into the cylinder, and the formed air-fuel mixture is ignited and burned. Although it is the same as the # 4 cylinder, after the combustion of the sucked fuel is finished, the reforming fuel is injected from the in-cylinder injection valve 54. The reforming fuel uses the same fuel such as gasoline as the fuel injection valve 50. The fuel pumped up from the fuel tank 20 by the low-pressure pump 22 is further supplied by the high-pressure pump 28 suitable for in-cylinder injection. Pump up and inject.

When in-cylinder injection of reforming fuel is performed during the period after combustion until the exhaust stroke is completed, the combustion gas in the cylinder is cooled and the pressure is reduced. Therefore, from the viewpoint of improving the efficiency of the engine, it is desirable that the injection timing is late in the expansion stroke. The injection timing may be an exhaust stroke. As an example, in this embodiment, fuel injection is started from 90 degrees after compression top dead center under the control of the engine control unit 200. The injected fuel is quickly evaporated by the high-temperature burned gas (combustion gas). A portion of the fuel reacts with the oxygen remaining in the combustion gas and burns, producing carbon dioxide, carbon monoxide, and water. However, since there is little oxygen in the combustion gas, it reacts with the burned gas components carbon dioxide and water to produce carbon monoxide and hydrogen. When the crank rotates and the exhaust valve 48 opens, the in-cylinder gas of the reforming cylinder 42 flows into the reforming catalyst 62 installed in the exhaust pipe 60 through the exhaust valve 48. By this reforming catalyst 62, the unreacted fuel is decomposed and reacted to generate a gas containing a large amount of CO and H ₂ .

Ideally, the composition of the combustion gas changes before and after the reforming reaction as shown in the following reaction equation (1), and the relationship between the coefficients a, n, m, and c is as shown in equation (2).

When the fuel composition in the reaction formula (1) is C ₇ H ₁₄ , the formula (2) becomes a = 2 + (2/7) c. The calorific value of the fuel is about 4.3 MJ / mol, and the calorific values of carbon monoxide and hydrogen, which are combustible gas components after the reaction (right side), are 0.28 MJ / mol for CO and 0 for H ₂ , respectively. .24 MJ / mol. Therefore, the value obtained by subtracting the heat value of the fuel before the reaction from the heat value of the combustible gas after the reaction is expressed by the following equation (3).
(21 + 2c) * 0.28 + (21 + 2c) * 0.24- (2+ (2c / 7)) * 4.3
= (21 + 2c) * 0.52- (2+ (2c / 7)) * 4.3
= 2.32-0.1886c (3)

Thus, Equation (3) is a linear function of the coefficient c of oxygen remaining in the combustion gas. Therefore, if c <12.3 is satisfied, the calorific value after the reaction increases. When the residual oxygen amount increases, the decrease in the calorific value due to the oxidation of the fuel to CO counteracts the effect of reducing the CO ₂ and H ₂ O and increasing the calorific value, so the calorific value gain decreases.

Here, the largest heating value gain is obtained when c = 0, that is, a condition in which fuel (reforming fuel) is added to gas burned at a stoichiometric ratio (theoretical air-fuel ratio). The calorific value of the gas increases to just under 127% of the fuel. The component of the gas burned at the stoichiometric air-fuel ratio (combustion gas) has an equivalent ratio of 1 with respect to the combustion reaction, and neither fuel nor oxygen remains. For this reason, as shown in the reaction formula (1), carbon monoxide and hydrogen having a mole number larger than a mole can be obtained from a mole fuel added for reforming. Specifically, n (1 + a) mol of CO and m (1 + a) / 2 mol of H ₂ can be obtained. Therefore, controlling the air-fuel ratio at the time of ignition combustion of the # 1 cylinder 42 to be a stoichiometric ratio is effective in realizing higher thermal efficiency. For this purpose, the intake air amount to the cylinder 42 is Is desirably controlled independently of the other cylinders 44. As shown in FIG. 1, it is preferable to provide a throttle valve 12 in the intake pipe 10 of the cylinder 42 and a flow meter 14 for measuring the flow rate. Further, the intake air amount and the fuel supply amount are controlled so that the stoichiometric air-fuel ratio is obtained, and the combustion gas obtained by burning in the cylinder 42 (in this embodiment, the mixture before fuel injection for reforming) It is preferable to control the equivalence ratio to be 1 or more so that there is no residual oxygen. More preferably, control is performed so that the equivalent ratio is 1 with less incomplete combustion.

  As described above, the exhaust pipe 60 of the cylinder # 1 is connected to the intake pipe 30 of the cylinders # 2 to # 4, and is mixed with fuel (in the case of injection into the intake port) and fresh air. It is sucked into the cylinder 44 and exhausted after ignition and combustion. The engine control unit 200 adjusts the flow rate of the intake amount into the cylinder 44 by the throttle valve 32 provided upstream, and the reformed gas amount is indirectly adjusted by the throttle valve 12 and the flow meter 14 of the cylinder 42, The amount of fuel injection controls the amount of fuel injected from the fuel injection valve 50 and the like. In this way, the exhaust gas from the cylinders # 2 to # 4 is controlled so that the equivalence ratio becomes 1, so that the purification reaction at the exhaust purification catalyst 72 can be executed reliably.

With the above operation, even when the thermal efficiency of the engine itself does not change, the amount of heat generated by the fuel increases, so that the thermal efficiency of the entire system is improved. Further, CO ₂ and H ₂ O necessary for exhaust gas reforming in the # 1 cylinder 42 can be obtained by engine combustion, as can be understood from the left side (combustion gas component) of the reaction formula (1). At the same time, the engine combustion is executed in the cylinder 42, so that power can be taken out.

In the present embodiment, the reformed gas obtained from the exhaust gas (combustion gas) in the reforming cylinder 42 is supplied to the other cylinders 44. Since the reformed gas can be obtained from the exhaust gas in this way, the working gas volume in the other cylinders 44 can be increased. In particular, CO and H ₂ can be obtained as the reformed gas, and the number of moles increases as described above, so the effect of increasing the working gas volume is great. Further, since the equivalence ratio is controlled to be constant, it is necessary to reduce the intake air amount in a partial load state where the supplied fuel is small. However, since the working gas amount can be increased by the reformed gas, Energy required for inhalation, that is, gas exchange loss at partial load can be reduced.

  Here, in the above description, for the cylinders # 2 to # 4, the fuel injection valve 50 is provided and the fuel from the fuel tank 20 and the reformed gas are used together as the fuel for the mixture combustion. It is also possible to use all the fuel in the cylinders 2 to # 4 as reformed gas. In this case, the fuel injection valve 50 for the cylinder 44 shown in FIG. 1 is omitted. As described above, when only the reformed gas is used as the fuel for the cylinder 44, the reformed gas supply means includes a reformed gas injection valve that can control at least the injection timing and the injection amount in the vicinity of the intake port of the cylinder 44 or the cylinder. It is preferable to provide in 44 cylinders. Thus, the internal combustion engine 100 of this embodiment can achieve the highest efficiency by using all the fuel in the cylinder 44 as the reformed gas. On the other hand, as shown in FIG. 1, the fuel injection valves are provided in the intake ports or cylinders of the # 2 to # 4 cylinders, and in response to a load change (torque request), when the load is high (torque request is large), A fuel such as gasoline other than the reformed gas may be used in combination.

(Modification 1)
FIG. 2 shows a first modification of the internal combustion engine according to the embodiment. 1 differs from the internal combustion engine 100 of FIG. 1 in that an in-cylinder injection valve 56 for water injection of the reforming cylinder 42 is provided, and the water tank 24 to the pump 26 are provided in the reforming cylinder. It is to inject the water pumped up. About another point, it is as the above-mentioned, and abbreviate | omits description. By injecting water, water gas reaction in the reforming reaction is easily caused and carbon deposition is suppressed. As shown in the above reaction formula (1), in the reforming reaction of the combustion gas, water (steam) in the combustion gas becomes a hydrogen material of the reformed gas component. Then, by supplying the water present in the left side (material) of the reforming reaction into the cylinder, the reforming reaction can be advanced to the right side of the reaction formula, and the reforming reaction can be performed without increasing the fuel consumption. It becomes possible to improve the heat efficiency of the internal combustion engine 110 as a whole.

  Here, the water injection is used to advance the reforming reaction in addition to the suppression of carbon deposition as described above. Similar to the fuel injection timing for reforming, after the combustion, the exhaust stroke is completed. In the meantime, more specifically, it is preferable to carry out the exhaust stroke as much as possible after the expansion stroke. By controlling the water injection timing together with the fuel injection timing for reforming, the engine control unit 200 can add water to the mixed gas of combustion gas and reforming fuel at an appropriate time. it can. If water is injected during the period until completion of exhaust after such combustion, the injected water immediately becomes water vapor due to the heat of the combustion gas, and can contribute to the progress of the reaction efficiently. In-cylinder injection of fuel and water may be performed first, but from the viewpoint of alleviating a rapid drop in the in-cylinder temperature, it is preferable to perform the incline rather than injecting simultaneously.

(Modification 2)
FIG. 3 shows another modification 2 of the internal combustion engine according to the above embodiment. A difference from the internal combustion engine 100 of FIG. 1 is that in the internal combustion engine 120 of the second modification, an emulsion of water and fuel (reforming fuel) is injected from the in-cylinder injection valve 58 of the cylinder 42 of # 1. is there. In addition to the fuel tank 20, a water tank 24 is provided, and the water pumped from the water tank 24 by the low pressure pump 26 and the fuel pumped from the fuel tank 20 by the low pressure pump 22 are pumped by the high pressure pump 28 to form an emulsion state. The high-pressure pump 28 supplies water and fuel emulsion to the in-cylinder injection valve 58. By supplying fuel and water into the cylinder in an emulsion state, it is possible to prevent the fuel and water from being separated in the cylinder.

It is a figure explaining the outline of the internal-combustion engine concerning an embodiment. It is a figure explaining the outline of the internal combustion engine which concerns on the modification 1. FIG. It is a figure explaining the outline of the internal combustion engine which concerns on the modification 2. FIG.

Explanation of symbols

  10, 30 Intake pipe, 12, 32 Throttle valve, 14 Flow meter, 20 Fuel tank, 22, 26 Low pressure pump, 28 High pressure pump, 40 cylinder, 42 Reforming cylinder (# 1), 44 Other than for reforming Cylinders (# 2 to # 4), 45 spark plug, 46 intake valve, 48 exhaust valve, 50 fuel injection valve, 51 reformed gas container (reformed gas gallery), 52 reformed gas supply means, 53 reformed Gas nozzle, 54 In-cylinder (fuel) injection valve, 56 Water injection valve, 58 In-cylinder injection valve, 60, 70 Exhaust pipe, 62 Reforming catalyst, 64 Reformed gas supply pipe, 66 Cooler, 72 Exhaust purification catalyst, 200 Engine control unit.

Claims (8)

An internal combustion engine having a plurality of cylinders,
Among the plurality of cylinders, at least one cylinder is a reforming cylinder having an exhaust gas reforming function and includes an in-cylinder injection valve,
A reformed gas supply means for supplying a reformed gas to at least a cylinder other than the reforming cylinder among the plurality of cylinders via an exhaust pipe of the reforming cylinder;
In the cylinder for reforming, the in-cylinder injection valve is injected into the cylinder in the period from the combustion of the air-fuel mixture containing fuel and air supplied into the cylinder to the completion of exhaust of the combustion gas from the cylinder. An internal combustion engine characterized by injecting reforming fuel from a gas to create a mixed gas of the exhaust gas and reforming fuel. The internal combustion engine according to claim 1,
In the plurality of cylinders, an air-fuel mixture of fuel and air is supplied, and combustion is performed.
After the combustion, the internal combustion engine is characterized in that the reforming fuel is injected into the cylinder only in the reforming cylinder to create a mixed gas of the exhaust gas and the fuel. The internal combustion engine according to claim 1 or 2,
In the reforming cylinder, the fuel gas in the reforming cylinder is equal to or greater than 1 after injecting the reforming fuel after burning the mixture containing the fuel and air. An internal combustion engine that is controlled. The internal combustion engine according to any one of claims 1 to 3,
An internal combustion engine controlled so that an equivalence ratio of exhaust gas at least in a cylinder other than the reforming cylinder is 1. The internal combustion engine according to any one of claims 1 to 4,
An internal combustion engine characterized in that there are a plurality of in-cylinder injection valves of the reforming cylinder, at least one of which is an injection valve that injects a liquid containing water. The internal combustion engine according to any one of claims 1 to 4,
The internal combustion engine, wherein the in-cylinder injection valve of the reforming cylinder is an injection valve that injects reforming fuel containing water. The internal combustion engine according to any one of claims 1 to 6,
The internal combustion engine, wherein an exhaust pipe of the reforming cylinder is connected to an intake pipe of a cylinder other than the reforming cylinder, and a connecting path includes a flow rate adjusting valve for adjusting a reformed gas flow rate. The internal combustion engine according to any one of claims 1 to 7,
An internal combustion engine characterized in that a reforming catalyst for advancing a reforming reaction of a mixed gas of the exhaust gas and the reforming fuel is provided in an exhaust pipe of the reforming cylinder.

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