JP5206471B2 - Premixed compression self-ignition internal combustion engine - Google Patents

Description

  The present invention relates to a premixed compression self-ignition internal combustion engine.

The internal combustion engine of the premixed compression self-ignition type (HCCI (Homogeneous-Charge Compression-Ignition) system) is an internal combustion engine that employs an ignition system that compresses and self-ignites a mixture of fuel and air mixed in advance in the combustion chamber. is there. According to this internal combustion engine, high output, reduction of NOx (nitrogen oxide) and CO ₂ (carbon dioxide), and improvement of fuel consumption can be achieved simultaneously.

  Patent Document 1 discloses a technique related to such an internal combustion engine. According to the technique disclosed in Patent Document 1, two injection valves that directly inject high self-ignition fuel (low-octane fuel) and low self-ignition fuel (high octane fuel) are injected into the combustion chamber. Using the fuel injection valve, the fuel is distributed and injected so as not to overlap. This suppresses generation of NOx and smoke, and early ignition during high-load operation.

JP-A-2005-139945

  Incidentally, in the internal combustion engine disclosed in Patent Document 1, combustion in the fuel chamber proceeds as follows. That is, in the compression stroke, combustion is started from a high self-ignitable fuel having a high self-ignitability, and when the compression further proceeds, the combustion shifts to a low self-ignitable fuel having a low self-ignitability.

  However, if the distribution ratio of low self-ignitable fuel is higher than that of high self-ignitable fuel, the combustion noise generated during the transition to low self-ignitable fuel combustion will increase or the low self-ignitable fuel will increase. There is a problem that the amount of unburned fuel of low self-igniting fuel increases without shifting to combustion.

  The present invention has been made in view of such a technical problem. Generation of combustion noise and emission amount of unburned fuel related to combustion transition from combustion of high autoignition fuel to combustion of low autoignition fuel It is an object of the present invention to provide a premixed compression self-ignition internal combustion engine that prevents an increase in the internal combustion engine.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected, it is not limited to this.

The present invention relates to a premixed compression self-ignition internal combustion engine (1) in which an air-fuel mixture of air and three or more fuels is combusted by compression self-ignition in a combustion chamber (2), wherein the three or more fuels are , different have self-ignitability, the distribution ratio of the fuel to all the fuel distribution in the combustion chamber (2) is characterized in that the distribution ratio of the fuel a higher self-ignitability of the fuel is a high .

  According to the present invention, the use of three or more fuels having different self-ignitability, and the higher the fuel self-ignitability, the higher the fuel distribution ratio, so that the rapid pressure increase associated with the combustion of each fuel Therefore, the generation of combustion noise related to combustion transition can be prevented. In addition, since the start timing of combustion of each fuel can be optimized, an increase in the amount of unburned fuel discharged can be prevented.

It is a figure explaining the structure of the whole system which concerns on the 1st Embodiment of this invention. It is a figure explaining the relationship between the self-ignition property of a fuel, and a distribution ratio. It is a figure explaining the distribution area | region of each fuel when the combustion chamber 2 of FIG. 1 is seen from upper direction. It is a figure explaining the relationship between a crank angle and a heat release rate. It is a figure explaining the structure of the whole system which concerns on the 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the present invention will be described by taking as an example a case where the present invention is applied to an ignition-type internal combustion engine in which a mixture of fuel and air mixed in advance is compressed in a combustion chamber and self-ignited.

[First embodiment]
First, a first embodiment of the present invention will be described.

(System configuration)
FIG. 1 is a diagram illustrating the configuration of the entire system according to the first embodiment of the present invention. In the internal combustion engine 1 shown in FIG. 1, a combustion chamber (main combustion chamber) 2 is formed by a cylinder head 31, a cylinder block 32, and a piston 33.

  The piston 33 is a member that reciprocates along the inner peripheral surface 32 a of the cylinder block 32. A piston cavity 34 (hereinafter simply referred to as “cavity 34”), which is a cylindrical depression, is formed on the crown surface 33 a of the piston 33. The cavity 34 includes a planar bottom surface portion 34a, a wall surface portion 34b extending substantially perpendicularly from the outer edge of the bottom surface portion 34a toward the crown surface 33a, and an oblique portion extending obliquely from the wall surface portion 34b toward the crown surface 33a. 34c.

  The internal combustion engine 1 according to the present embodiment includes a low self-ignition fuel injection valve 11, a high self-ignition fuel injection valve 12, a medium self-ignition fuel injection valve 13, a fuel tank 14, a reformer (fuel reforming). Apparatus) 15 etc. are provided. The injection valves 11 to 13 are multi-hole fuel injection valves in which a plurality of injection holes are arranged at equal intervals on the circumference so that the injected fuel spray forms a hollow cone as a whole.

  The low self-igniting fuel injection valve 11 is an injection valve that directly injects low self-igniting fuel (high octane fuel) into the combustion chamber 2. Low self-ignitable fuel is fuel with low self-ignitability, such as gasoline. As shown in FIG. 1, the low self-ignition fuel injection valve 11 is disposed such that its injection range (the destination of the hollow conical fuel spray) is the crown surface 33a. If the injection timing of the injection valve 11 is set to the first half of the intake stroke or the compression stroke, it is possible to form a homogeneous mixture of fuel such as gasoline having low self-ignitability in the entire combustion chamber 2.

  The high self-ignition fuel injection valve 12 is an injection valve that directly injects high self-ignition fuel (low octane fuel) into the combustion chamber 2. The high self-ignitable fuel is a fuel having high self-ignitability such as light oil. As shown in FIG. 1, the highly self-igniting fuel injection valve 12 is disposed such that its injection range is the bottom surface portion 34 a of the cavity 34.

  The medium self-ignitable fuel injection valve 13 is an injection valve that directly injects medium self-ignitable fuel into the combustion chamber 2. The medium self-ignitable fuel is a fuel having self-ignitability between the low self-ignitable fuel and the high self-ignitable fuel described above. As shown in FIG. 1, the middle self-igniting fuel injection valve 13 is disposed such that its injection range is an inclined portion 34 c and a bottom surface portion 34 a of the cavity 34.

  The fuel tank 14 is a storage unit for storing predetermined self-ignitable fuel supplied from the outside. The fuel stored in the fuel tank 14 is supplied to the reformer 15 via a fuel pump (not shown).

  The reformer 15 is a device for reforming the characteristics of the fuel supplied from the fuel tank 14, and is interposed in, for example, an exhaust port (not shown) of the internal combustion engine 1. The reformer 15 reforms a predetermined self-ignitable fuel so that the self-ignitability of the fuel becomes higher or lower. For example, when the fuel before reforming is a highly self-igniting fuel, it is reformed so as to have a low self-igniting property using exhaust heat and a dehydrogenation reaction catalyst. In this way, a low self-ignitable fuel, a high self-ignitable fuel, and a medium self-ignitable fuel having intermediate self-ignitability are generated.

  As described above, in the internal combustion engine 1 according to the present embodiment, the low self-ignition fuel injection valve 11 injects the low self-ignition fuel into the entire crown surface 33 a and the cavity 34, and the high self-ignition fuel injection valve 12. High self-ignitable fuel is injected into the bottom surface portion 34 a of the cavity 34, and medium self-ignitable fuel is injected into the oblique portion 34 c of the cavity 34 and the bottom surface portion 34 a of the cavity 34 by the medium self-ignitable fuel injection valve 13. The self-ignitability of these fuels is controlled by the equivalence ratio and octane number.

  Injection by these fuel injection valves 11 to 13 is controlled by an ECU (Engine Control Unit) (not shown). Thereby, each fuel is distributed in the combustion chamber 2. The distribution mode of each fuel in the combustion chamber 2 at that time will be described below.

(About the distribution ratio of each fuel)
FIG. 2 is a diagram for explaining the relationship between fuel self-ignitability and distribution ratio. In FIG. 2, the horizontal axis represents the self-ignitability of the fuel, and the vertical axis represents the distribution ratio. The distribution ratio here is the ratio of the distribution of each fuel to the total fuel distribution when a plurality of different self-ignitable fuels are distributed in the combustion chamber 2 (see FIG. 1). FIG. 2 shows three examples of FIGS. 2A, 2B, and 2C with respect to the distribution ratio of each fuel. In addition, the vertical axis | shaft of FIG. 2 may show calorie | heat amount instead of a distribution ratio. The amount of heat referred to here is the amount of heat generated when an air-fuel mixture of each fuel and air is burned in the combustion chamber 2.

  In the internal combustion engine 1 according to the present embodiment, as shown in FIGS. 2A, 2B, and 2C in common, the higher the fuel self-ignitability (the lower the octane number of the fuel), the fuel The distribution ratio is increased continuously or stepwise. At least, the distribution ratio (generated heat quantity, fuel quantity) of the centrally ignitable fuel is higher than the distribution ratio (generated heat quantity, fuel quantity) of the high self-ignitable fuel, and the distribution ratio (generated heat quantity) of the low self-ignitable fuel. The amount of distribution (the amount of generated heat and the amount of fuel) with respect to self-ignitability must not increase continuously or monotonously. By supplying three fuels having different self-ignitability, the distribution ratio of the central fuel is higher than the distribution ratio of the high self-ignition fuel and lower than the distribution ratio of the low self-ignition fuel. Anyway.

  In the example shown in FIG. 2 (a), the higher the fuel self-ignitability (the lower the octane number), the higher the fuel distribution ratio is in a linear function. For example, when three types of self-ignitable fuels having different self-ignition properties T1 (low self-ignition property), T2 (medium self-ignition property), and T3 (high self-ignition property) are distributed (like the internal combustion engine 1 in FIG. 1) In this case, the distribution ratio is increased linearly in the order of self-ignitability T1, T2, and T3.

  As shown in FIG. 2B, the distribution ratio in the vicinity of T1, that is, in the vicinity of low self-ignitability is increased to increase the vicinity of T2, as shown in FIG. That is, the distribution ratio in the vicinity of medium self-ignitability may be lowered. In this case as well, the higher the fuel self-ignitability is, the higher the fuel distribution ratio is, as in FIG.

  Further, as shown in FIG. 2 (c), the distribution ratio in the vicinity of T1 and T2, that is, low self-ignitability to medium self-ignition characteristics is decreased, and the distribution ratio in the vicinity of T3, that is, high auto-ignition characteristics is increased. May be. This is to suppress rapid combustion of the high self-ignitable fuel when the distribution ratio of the high self-ignitable fuel increases. In this case as well, the higher the fuel self-ignitability is, the higher the fuel distribution ratio is, as in FIG.

  As described above, in the internal combustion engine 1 according to the present embodiment, the distribution ratio of each fuel distributed in the combustion chamber 2 is controlled such that the higher the fuel self-ignitability, the higher the fuel distribution ratio. . This is realized by an ECU (not shown) controlling the fuel injection amount, fuel injection timing, fuel injection amount, fuel injection rate, and the like of each fuel injection valve 11 to 13. Specifically, for example, the high self-ignition fuel injection valve 11, the high self-ignition fuel injection valve 11, the middle self-ignition fuel injection valve 12, and the low self-ignition fuel injection valve 13 in this order so that the fuel injection amount increases. To maximize the fuel injection amount.

(Regarding the distribution area of each fuel)
The distribution ratio of each fuel distributed in the combustion chamber 2 has been described above. Next, the region in which each fuel is distributed will be described.

  FIG. 3 is a view for explaining a distribution region of each fuel when the combustion chamber 2 of FIG. 1 is viewed from above. As shown in FIG. 3, the distribution region of each fuel in the combustion chamber 2 is such that highly self-ignitable fuel is distributed on the central portion 2a side of the combustion chamber 2 (above the bottom surface portion 34a in FIG. 1). The self-ignitable fuel is distributed around the flammable fuel (above the oblique portion 34c in FIG. 1), and is located around the middle ignitable fuel (above the crown surface 33a in FIG. 1) and the outer periphery of the combustion chamber 2 The low self-ignitable fuel is distributed on the part 2b side.

  As described above, in the internal combustion engine 1 according to this embodiment, the distribution region of each fuel distributed in the combustion chamber 2 is distributed toward the central portion 2a side of the combustion chamber 2 as the ignitability increases, and the self-ignition property is increased. It controls so that it is distributed in layers so that it may go to the outer peripheral part 2b from the center part 2a of the combustion chamber 2, so that it is low. Specifically, it is realized by dividing the injection range of each fuel injection valve 11 to 13 according to the structure of the combustion chamber 2, that is, the shape of the piston 33 (see FIG. 1).

(About the effect by the internal combustion engine 1 which concerns on this embodiment)
FIG. 4 is a diagram for explaining the relationship between the crank angle and the heat generation rate. In FIG. 4, the horizontal axis represents CA (crank angle), and the vertical axis represents the heat generation rate. 4 (a), 4 (b), and 4 (c) respectively show an injection mode in which one self-ignitable fuel is injected into the combustion chamber 2, and two different self-ignitable fuels (low self-ignitability) into the combustion chamber 2. An injection mode in which fuel is injected) and an injection mode in which two different self-ignitable fuels (in the case of more high self-ignition fuel) are injected into the combustion chamber 2 are shown. FIG. 4D shows injection of three different self-ignitable fuels (high self-ignitable fuel, medium self-ignitable fuel, and low self-ignitable fuel) into the internal combustion engine 1, that is, the combustion chamber 2 according to the present embodiment. The injection mode is shown.

  In the injection mode shown in FIG. 4A, when ignited, combustion proceeds all at once, the heat generation rate increases, and the pressure increase rate becomes excessive. In the injection mode shown in FIG. 4 (b), it is possible to prevent the heat generation rate from increasing, but the combustion period becomes longer, so the amount of unburned fuel discharged increases. In the injection mode shown in FIG. 4 (c), the combustion of the low self-ignitable fuel proceeds in the vicinity of the top dead center, so that the heat generation rate at the time of ignition of the high self-ignitable fuel becomes large and the pressure increase rate becomes excessive. End up.

  On the other hand, in the injection mode of the internal combustion engine 1 according to the present embodiment shown in FIG. 4D, rapid heat generation related to combustion of each fuel is achieved by controlling the distribution of three different self-ignitable fuels. An increase in rate and an increase in pressure increase rate can be suppressed. Thereby, generation | occurrence | production of the combustion noise which concerns on the combustion transfer from combustion of highly self-ignitable fuel to combustion of low self-ignitable fuel can be suppressed. Further, it becomes possible to perform combustion after optimizing the combustion timing of each fuel. Thereby, the increase in the discharge amount of unburned fuel can be prevented.

[Second Embodiment]
Subsequently, a second embodiment of the present invention will be described. In the first embodiment described above, the embodiment using the three injection valves of the low self-ignition fuel injection valve 11, the high self-ignition fuel injection valve 12, and the middle self-ignition fuel injection valve 13 has been described. Here, the form using two injection valves, the low self-ignition fuel injection valve 21 and the high self-ignition fuel injection valve 22, will be described.

(System configuration)
FIG. 5 is a diagram illustrating the configuration of the entire system according to the second embodiment of the present invention. In the following description, the same reference numerals are given to portions that perform the same functions as those in FIG.

  The internal combustion engine 1 shown in FIG. 5 is provided with a low self-ignition fuel injection valve 21, a high self-ignition fuel injection valve 22, a low self-ignition fuel tank 23, a high self-ignition fuel tank 24, and the like. The injection valves 21 and 22 are multi-hole fuel injection valves in which a plurality of injection holes are arranged at equal intervals on the circumference so that the injected fuel spray forms a hollow cone as a whole.

  The low self-ignition fuel injection valve 21 is an injection valve that directly injects the low self-ignition fuel (high octane fuel) stored in the low self-ignition fuel tank 23 into the combustion chamber 2. As shown in FIG. 5, the low self-igniting fuel injection valve 21 is disposed such that its injection range is a crown surface 33a. If the injection timing of the injection valve 21 is set to the first half of the intake stroke or the compression stroke, it is also possible to form a homogeneous mixture of fuel such as gasoline with low self-ignitability in the entire combustion chamber 2.

  The high self-ignition fuel injection valve 22 is an injection valve that directly injects the high self-ignition fuel (low-octane fuel) stored in the high self-ignition fuel tank 24 into the combustion chamber 2. The highly self-igniting fuel injection valve 12 has an injection range as follows. That is, as the piston 33 rises (goes to the top dead center), the injection range becomes the bottom surface portion 34a, and as the piston 33 descends (goes to the bottom dead center), the injection range becomes the oblique portion 34c and the bottom surface portion 34a. It is arranged.

  The low self-ignition fuel tank 23 is a storage unit that stores low self-ignition fuel supplied from outside. The highly self-igniting fuel tank 24 is a storage unit that stores highly self-igniting fuel supplied from the outside.

  As described above, in the internal combustion engine 1 according to the present embodiment, the low self-ignition fuel injection valve 21 injects the low self-ignition fuel into the entire crown surface 33 a and the cavity 34, and the high self-ignition fuel injection valve 22. When the piston is raised, highly self-ignitable fuel is injected into the bottom surface portion 34a of the cavity 34, and when the piston is lowered, highly self-ignitable fuel is injected into the oblique portion 34c of the cavity 34 and the bottom surface portion 34a of the cavity 34. Injection by these fuel injection valves 21 and 22 is controlled by an ECU (Engine Control Unit) (not shown). Thereby, each fuel is distributed in the combustion chamber 2.

  The distribution mode of each fuel in the combustion chamber 2 at this time is the same as that in the first embodiment (see FIGS. 2 and 3). That is, as shown in FIG. 3, highly self-ignitable fuel is distributed on the central portion 2a side of the combustion chamber 2 (above the bottom portion 34a in FIG. 5), and around this highly self-ignitable fuel (oblique in FIG. 5). Medium self-ignitable fuel is distributed in the upper part 34c), and the low self-ignitable fuel is disposed around the medium self-ignitable fuel (above the crown surface 33a in FIG. 5) and on the outer peripheral part 2b side of the combustion chamber 2. Are distributed. Here, the medium self-ignitable fuel is a mixture of the low self-ignitable fuel injected by the low self-ignitable fuel injection valve 21 and the high self-ignitable fuel injected by the high self-ignitable fuel injection valve 22. To be formed. In other words, the mixture of medium self-ignitable fuel and air is formed by mixing the fuel spray of the low self-ignitable fuel and the fuel spray of the high self-ignitable fuel by colliding with the oblique portion 34c of the cavity 34. Is done. Further, as shown in FIG. 2, the distribution ratio of each fuel distributed in the combustion chamber 2 is controlled such that the higher the fuel self-ignitability, the higher the fuel distribution ratio.

  The distribution mode in the combustion chamber 2 as described above is realized by the ECU (not shown) controlling the fuel injection amount, the fuel injection timing, the fuel injection amount, the fuel injection rate, and the like of the fuel injection valves 21 and 22. . Specifically, for example, the fuel injection amount of the high self-ignition fuel injection valve 21 is controlled to be larger than that of the low self-ignition fuel injection valve 22. Further, the fuel injection valves 21 and 22 are injected twice, and control is performed so that the first and second injection amounts are changed.

  In order to set the distribution of each fuel in the combustion chamber 2 to the side of the self-ignitability higher than the self-ignitability of the low self-ignition fuel, the high self-ignition fuel injection valve 21 is used in the first half of the intake stroke or the compression stroke. Highly ignitable fuel is injected. On the other hand, in order to set this distribution to the self-ignitability side lower than the self-ignitability of the high self-ignitability fuel, the low self-ignition fuel injection valve 22 injects the low self-ignition fuel in the first half of the intake process or the compression process. Let

(Summary)
Each embodiment has been described above. However, according to the internal combustion engine 1 according to each embodiment, the higher the fuel self-ignitability is, the higher the fuel distribution ratio is. As a result, it is possible to suppress a rapid pressure increase related to the combustion of each fuel, and thus it is possible to prevent the generation of combustion noise related to combustion transition. In addition, since the start timing of combustion of each fuel can be optimized, an increase in the amount of unburned fuel discharged can be prevented.

  Further, according to the internal combustion engine 1 according to each embodiment, three different self-ignitable fuels, that is, a high self-ignitable fuel, a low self-ignitable fuel, and a medium self-ignitable fuel having self-ignitability therebetween. By using, it is possible to prevent the generation of combustion noise related to combustion transition and the increase in the amount of unburned fuel discharged.

  Further, according to the internal combustion engine 1 according to the first embodiment, predetermined self-ignitable fuel is reformed to generate high self-ignitable fuel, medium self-ignitable fuel, and low self-ignitable fuel. The reformer 15, the high self-ignition fuel injection valve 12 that directly injects the generated highly self-ignitable fuel into the combustion chamber 2, and the generated medium self-ignitable fuel is directly injected into the combustion chamber 2. Combustion using three injection valves by using the medium self-ignition fuel injection valve 13 and the low self-ignition fuel injection valve 11 that directly injects the generated low self-ignition fuel into the combustion chamber 2. Generation of combustion noise related to transition and increase in the amount of unburned fuel discharged can be prevented.

  Further, according to the internal combustion engine 1 according to the first embodiment, the distribution region of each fuel in the combustion chamber 2 is distributed toward the central portion 2a side of the combustion chamber 2 as the self-ignition property is higher, and the self-ignition property is lower. Since it is distributed in layers from the central portion 2a side to the outer peripheral portion 2b side of the combustion chamber 2, generation of NOx and smoke, and early ignition during high load operation can be suppressed.

  Further, according to the internal combustion engine 1 according to the first embodiment, the cavity 34 is formed in the crown surface 33 a and extends obliquely from the edge portion 33 b between the crown surface 33 a and the cavity 34 toward the inside of the cavity 34. A piston 33 having an inclined portion 34c is provided, the highly self-igniting fuel injection valve 12 is controlled to inject toward the inside of the cavity 34 relative to the inclined portion 34c, and the middle self-igniting fuel injection valve 13 is controlled by the inclined portion 34c. And the low self-igniting fuel injection valve 11 is controlled to inject over the entire crown surface 33a, so that three injection valves are used as described above. A layered distribution can be formed.

  Further, according to the internal combustion engine 1 according to the first embodiment, the high self-ignition fuel tank 24 that stores high self-ignition fuel, the low self-ignition fuel tank 23 that stores low self-ignition fuel, High self-ignition fuel injection valve 22 for directly injecting stored high self-ignition fuel into combustion chamber 2 and low self-ignition fuel injection for injecting stored low self-ignition fuel directly into combustion chamber 2 A low self-igniting fuel injected by the high self-igniting fuel injection valve 22 and a low self-igniting fuel injected by the low self-igniting fuel injection valve 21. Therefore, it is possible to prevent the generation of combustion noise related to the combustion transition and the increase in the discharge amount of unburned fuel by using the two injection valves.

  Further, according to the internal combustion engine 1 according to the second embodiment, the distribution region of each fuel in the combustion chamber 2 is distributed toward the central portion 2a side of the combustion chamber 2 as the self-ignition property is higher, and the self-ignition property is lower. Since it is distributed in layers from the central portion 2a side to the outer peripheral portion 2b side of the combustion chamber 2, generation of NOx and smoke, and early ignition during high load operation can be suppressed.

  Further, according to the internal combustion engine 1 according to the second embodiment, the cavity 34 is formed in the crown surface 33 a and extends obliquely from the edge 33 b between the crown surface 33 a and the cavity 34 toward the inside of the cavity 34. A piston 33 having an inclined portion 34c is provided. The piston 33 sprays into the cavity 34 as it goes to the top dead center, and the piston 33 moves toward the bottom dead center with respect to the inclined portion 34c and the cavity 34. Since the low self-igniting fuel injection valve 21 is controlled to inject the entire crown surface 33a, the above-described layered distribution is formed using two injection valves. Can do.

  Each embodiment of the present invention has been described above. However, each of the above embodiments shows one application example of the present invention, and the technical scope of the present invention is limited to the specific configuration of each of the above embodiments. It is not the purpose.

  Further, for example, in the above description, FIG. 3 shows that each fuel is distributed in a layered manner. However, if the distribution ratio of each fuel satisfies the relationship shown in FIG. 2, the distribution mode is not limited to a layered shape. .

1 Internal combustion engine (premixed compression self-ignition internal combustion engine)
2 Combustion chambers 11, 21 Low self-ignition fuel injection valves 12, 22 High self-ignition fuel injection valves 13 Medium self-ignition fuel injection valves 14 Fuel tank 15 Reformer (fuel reformer)
23 Low self-igniting fuel tank 24 High self-igniting fuel tank 34 Piston cavity 34c Slanted part

Claims (8)

A premixed compression self-ignition internal combustion engine in which an air-fuel mixture of air and three or more fuels is combusted by compression self-ignition in a combustion chamber,
The three or more fuels have different autoignition properties;
A premixed compression self-ignition internal combustion engine characterized in that the distribution ratio of each fuel to the total fuel distribution in the combustion chamber is such that the higher the fuel self-ignitability, the higher the fuel distribution ratio. The three or more fuels are high self-ignitable fuel, low self-ignitable fuel, and medium self-ignitable fuel having self-ignitability between the high self-ignitable fuel and the low self-ignitable fuel. The premixed compression self-ignition internal combustion engine according to claim 1.   A fuel reformer that reforms a predetermined self-ignitable fuel to produce a high self-ignitable fuel, a medium self-ignitable fuel, and a low self-ignitable fuel, and the generated high self-ignitable fuel A highly self-igniting fuel injection valve that directly injects into the combustion chamber, a medium self-igniting fuel injection valve that directly injects the generated medium self-igniting fuel into the combustion chamber, and the generated low self-igniting fuel. The premixed compression self-ignition internal combustion engine according to claim 2, further comprising a low self-ignition fuel injection valve that directly injects the fuel into the combustion chamber.   The distribution region of each fuel in the combustion chamber is distributed toward the center of the combustion chamber as the self-ignition property is higher, and is distributed in a layered manner from the center of the combustion chamber toward the outer periphery as the self-ignition property is lower. The premixed compression self-ignition internal combustion engine according to claim 3, wherein Forming a cavity in a crown surface, comprising a piston having an oblique portion extending obliquely from the edge between the crown surface and the cavity toward the inside of the cavity;
The highly self-igniting fuel injection valve is controlled to inject into the inside of the cavity from the oblique portion, and the medium self-igniting fuel injection valve is injected into the oblique portion and the inside of the cavity. 5. The premixed compression self-ignition internal combustion engine according to claim 4, wherein the low self-ignition fuel injection valve is controlled so as to inject the entire crown surface. A high self-igniting fuel tank that stores high self-igniting fuel, a low self-igniting fuel tank that stores low self-igniting fuel, and a high self-injecting fuel that directly injects the stored high self-igniting fuel into the combustion chamber. An ignitable fuel injection valve; and a low self-ignition fuel injection valve that directly injects the stored low-ignition fuel into the combustion chamber,
The medium self-ignitable fuel is formed by mixing high self-ignitable fuel injected by the high self-ignitable fuel injection valve and low self-ignitable fuel injected by the low self-ignitable fuel injection valve. The premixed compression self-ignition internal combustion engine according to claim 2, wherein   The distribution region of each fuel in the combustion chamber is distributed toward the center of the combustion chamber as the self-ignition property is higher, and is distributed in a layered manner from the center of the combustion chamber toward the outer periphery as the self-ignition property is lower. The premixed compression self-ignition internal combustion engine according to claim 6, wherein Forming a cavity in a crown surface, comprising a piston having an oblique portion extending obliquely from the edge between the crown surface and the cavity toward the inside of the cavity;
The highly self-igniting fuel injection valve injects into the cavity as the piston moves toward the top dead center, and injects into the oblique portion and the cavity as the piston moves toward the bottom dead center. 8. The premixed compression self-ignition internal combustion engine according to claim 7, wherein the low self-ignition fuel injection valve is controlled to inject the entire crown surface.

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