JP2001303956A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably generate spontaneous ignition near the top dead center in an internal combustion engine using compression spontaneous ignition combustion of a combustible mixture. SOLUTION: At least in an initial stage of a compression stroke, the air and combusted gas in the cylinder constitute a state having a concentration distribution, and a strong turbulence is generated in the cylinder inside near the compression top dead center so that the agitation of the gas is accelerated to reduce the concentration distribution between the air and combusted gas in the cylinder. A squish part, which has an effect of the gas jetting in a part of a small interval toward the part of a wide interval in a compression stroke where the interval between a piston and the cylinder head is uneven in the top dead center, and the air flowing in a part of the wide interval into the part of the narrow interval in the expansion stroke, is arranged for generating the strong turbulence. The area of the squish part is set to not less than 25% and not more than 75% of the cylinder bore area and the interval of the squish in the top dead center is set to 3 mm or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine utilizing self-ignition combustion of a combustible air-fuel mixture by compression.

[0002]

2. Description of the Related Art For the purpose of improving the thermal efficiency of an internal combustion engine and reducing harmful emissions, research and development of an internal combustion engine utilizing self-ignition combustion of a combustible air-fuel mixture have been promoted. For example, it is known that a compression ignition internal combustion engine that employs a compression ignition combustion method of a lean mixture can obtain high thermal efficiency and can suppress the emission concentration of nitrogen oxides to several ppm or less. In addition, a method has been proposed in which the fuel injection timing of a diesel engine is advanced earlier to increase the degree of dispersion of the fuel and realize auto-ignition combustion in a wide range, and in addition to the same effects as described above, smoke emission can be reduced. Have been reported.

However, in such internal combustion engines utilizing self-ignition combustion, the occurrence of self-ignition depends on the reactivity of the air-fuel mixture and the history of pressure and temperature rise associated with piston compression. Some external control was required to maintain an appropriate ignition timing within the range. For example, in order to maintain an appropriate ignition timing over a wide range of engine speed and required load, control of compression temperature by a variable compression ratio system, control of self-ignition delay by adjusting fuel properties, or mixing of burned gas It is proposed to adjust the mixture temperature and the dilution ratio by performing the method, and any of the methods can theoretically adjust the ignition timing. Here, the burned gas means a gas burned in a previous cycle, and indicates a residual gas or a recirculated exhaust gas.

[0004] However, both of the above approaches have essentially the same problem. That is, unlike the conventional spark ignition type internal combustion engine or diesel engine, the start of combustion cannot be controlled immediately before combustion. In any of the above methods, basically, the control must be completed at the time when compression is started, that is, much earlier than the spark ignition timing in a conventional spark ignition type internal combustion engine or the injection timing in a diesel engine. For this reason, any of the above-mentioned methods is one of the problems that require high-precision and precise control in realizing it, making it difficult to realize.

In the compression ignition type internal combustion engine, the chemical reaction between the fuel molecules and the oxygen molecules in the combustible mixture is accelerated as the temperature rises due to the compression, and the chain reaction proceeds extremely rapidly, so that the self ignition combustion Leads to. Therefore, in order to generate self-ignition in the process of decreasing the temperature,
The activity of the chain reaction formed in the reaction process before the start of the temperature drop must be increased so that the activity of the chain reaction caused by the temperature drop is not lowered so as not to cause auto-ignition.

[0006] However, it is not easy to stably and reliably form such conditions, and in the compression self-ignition type internal combustion engine, even if it is attempted to start self-ignition in the expansion stroke, misfire easily occurs and control is not easy. There is a problem.
A technique for mixing the burned gas with newly supplied air to generate self-ignition combustion is disclosed in, for example, Japanese Patent Application Laid-Open No. H11-236833. According to the invention, a four-stroke cycle engine is provided with a means for changing the opening / closing timing of intake and exhaust valves, thereby adjusting the temperature of the air-fuel mixture and the effect of dilution to achieve appropriate combustion.

However, this method is a combination of the control of the compression temperature by the variable compression ratio system and the adjustment of the mixture temperature and the dilution ratio by the residual gas and the recirculated exhaust gas. It does not solve the problem related to typical self-ignition control.

In a two-stroke cycle internal combustion engine, ATAC (S. Ohnishi et al., "
Active Thermo-Atomosphere Combustion (ATAC)-A Ne
w Combsution Process for Internal Combustion Engin
es ", SAE Paper 790501, (1979).) and AR combustion (Y. Ishib
ashi et al., "A Low Pressure Pneumatic Direct Inje
ction Two-Stroke Engine by Activated Radical Combu
stion Concept ", SAE paper 980757, (1998).) However, even in these prior arts, the ratio of the residual gas in the cylinder is reduced by changing the timing of closing the scavenging holes. The self-ignition is controlled by adjusting and changing the effective compression ratio, and does not solve the above-mentioned problem relating to the essential self-ignition control.

Japanese Patent Application Laid-Open No. 54-55208 discloses similar inventions, but these inventions relate to low- and medium-load spark-ignition two-stroke cycle internal combustion engines. The purpose of the present invention is to improve the unstable combustion in the region, which is essentially different from the present invention in addition to the self-radical generated at the contact surface between the high-temperature residual gas and the low-temperature new air-fuel mixture. It is described as utilizing ignition, and does not have a concept of positively mixing radicals or the like of the residual gas itself into a combustible air-fuel mixture. In other words, this does not solve the essential problem of the related art in that the intentional action for causing self-ignition is almost completed at the start of compression.

[0010]

In an internal combustion engine that utilizes the compression auto-ignition combustion of a combustible mixture in all or a part of the combustion process in one cycle, it is easy to stably generate auto-ignition near top dead center. Rather, early ignition and misfire are likely to occur. The problem to be solved by the present invention is to provide a configuration that facilitates stable self-ignition in the vicinity of top dead center for an internal combustion engine that uses compression auto-ignition combustion of the combustible mixture. is there.

Hereinafter, the necessity of stably generating auto-ignition near the top dead center will be described with reference to the drawings. FIG. 1 shows an example in which the influence of the combustion start crank angle on the thermal efficiency is obtained by numerical calculation. The combustion start crank angle at which the thermal efficiency becomes maximum approaches the top dead center as the combustion period is shorter, and under the condition of a combustion period of 1 degree which can be said to be almost instantaneous combustion, at a time later than the top dead center, that is, at the very beginning of the expansion stroke. It can be seen that starting combustion is important for obtaining high thermal efficiency. In addition, it can be understood that the shorter the combustion period, the higher the thermal efficiency can be obtained. That is, it can be understood that it is important for an internal combustion engine aimed at high efficiency to start combustion near the top dead center and complete the combustion in a short time.

FIG. 1 also shows the degree of change in the thermal efficiency with respect to the change in the combustion start crank angle. According to this, when the combustion period is longer (e.g., a combustion period of 50 degrees crank angle), the change in the thermal efficiency is smaller even if the combustion start crank angle is changed. It can be seen that the effect of the combustion start crank angle on the change in the thermal efficiency is greater as the angle of combustion starts. That is, it can be understood that it is important to prevent a decrease in thermal efficiency due to early ignition when realizing combustion that is completed in a short time for high efficiency as combustion of the internal combustion engine. this is,
For example, it shows the importance of realizing stable self-ignition in the vicinity of top dead center in an internal combustion engine using the compression self-ignition combustion of the combustible mixture.

FIG. 2 shows an example in which the relationship between the combustion period and the air-fuel ratio (A / F) with respect to the combustion start crank angle at which the thermal efficiency becomes maximum is obtained by numerical calculation. As shown in FIG. 1, the combustion start crank angle at which the thermal efficiency becomes maximum as the combustion period is shortened becomes near the top dead center. Assuming that the combustion period is within 20 ° crank angle to achieve high-efficiency rapid combustion, the combustion start crank angle at which the thermal efficiency becomes maximum is later than the 5 ° crank angle before top dead center, and the range is A / A. F
Is hardly affected by

That is, from the results of these analyses, in combustion of an internal combustion engine aimed at high efficiency, regardless of A / F,
It can be concluded that it is necessary to make the combustion completed in a short time near the top dead center.

Next, the results of the self-ignition characteristics observed in the internal combustion engine using the compression self-ignition combustion of the combustible mixture will be described. In general, a practical method for controlling the self-ignition timing has not been established in an internal combustion engine utilizing the compression self-ignition combustion of a combustible mixture. Here, the results of examining the change in the ignition timing by changing the supply amount (the amount of new air supplied into the cylinder) and the ratio of the burned gas while the supply fuel amount is kept constant are shown.

FIG. 3 shows typical characteristics obtained from an engine experiment. According to FIG. 3, the ignition timing is monotonously delayed by increasing the air supply amount, which may be considered to be due to the decrease in the A / F due to the decrease in the burned gas in the cylinder and the decrease in the mixture temperature. it can. Further increase in air supply will lead to misfire. That is, this characteristic indicates that, in the internal combustion engine using the compression ignition combustion of the combustible mixture, the ignition timing is easily affected by the change in the supply air amount,
In particular, the occurrence of self-ignition after TDC also indicates that sudden misfire is likely to occur.

Therefore, it is difficult to stably realize the start of combustion after top dead center, which is effective in reducing nitrogen oxides and suppressing combustion noise (sound similar to knocking and knocking) due to rapid combustion. It can be said that there is.

[0018]

According to a first aspect of the present invention, there is provided a compression ignition system in which self-ignition combustion of a combustible air-fuel mixture is generated in all or a part of a combustion process in one cycle. -Type or spark ignition type internal combustion engine, having a region in which the concentration of burned gas is extremely high in the cylinder at the latter stage of the compression stroke, and disturbing the gas in the cylinder near the compression top dead center in the cylinder. The internal combustion engine is configured to cause the following.

The invention according to claim 2 has a region in which the burned gas concentration is extremely high in the cylinder at least at the beginning of the compression stroke, and the fuel supplied to the cylinder has the burned gas concentration extremely low. The internal combustion engine according to claim 1, wherein the internal combustion engine is configured to be present only in a part of the high region.

According to a third aspect of the present invention, a fuel supply device is provided in a passage through which air supplied to a cylinder passes, and when the air, fuel and burned gas are charged into the cylinder. 3. The internal combustion engine according to claim 1, wherein the mixture of the air and the burned gas is suppressed.

According to a fourth aspect of the present invention, there is provided a fuel injection valve for directly supplying fuel spray into a cylinder, and when the cylinder is filled with air and burned gas, the air and the burned gas are mixed. 3. The internal combustion engine according to claim 1, wherein the mixture of gases is suppressed, and the fuel spray is not mixed with at least a part of the burned gas at the time of fuel supply.

According to a fifth aspect of the present invention, the volume ratio of the burned gas to the newly supplied air in the cylinder during the compression stroke is determined by the ratio of the burned gas to 3 and the air to 7. The internal combustion engine according to any one of claims 1 to 4, wherein a lower limit is set, and a volume ratio of the burned gas is equal to or higher than the ratio.

According to a sixth aspect of the present invention, the squish portion is configured such that a gap is reduced in a part of the combustion chamber at the top dead center as compared with other parts. An internal combustion engine as described. That is, in the present invention, in order to cause the above-mentioned strong turbulence, the gap between the piston and the cylinder head at the top dead center is not uniform, and in the compression stroke, the gas in the small gap portion is directed toward the wide gap portion. In the ejection and expansion strokes, a squish portion is provided which has an effect that gas in a wide gap portion flows into a narrow gap portion.

According to a seventh aspect of the present invention, the area of the squish portion is set to 25% or more and 75% or less of the cylinder bore area, and the gap at the top dead center of the squish portion is set to 3 mm or less. Internal combustion engine.

More specifically, the present invention provides a compression ignition type or spark ignition type internal combustion engine in which the air and burned gas in the cylinder have a concentration distribution at least at the beginning of the compression stroke. This is realized by generating a strong turbulence in the cylinder near the compression top dead center to promote gas agitation and reducing the concentration distribution of air and burned gas in the cylinder.

FIG. 4 schematically shows the state in the cylinder intended by the present invention, taking a two-stroke cycle type internal combustion engine as an example. The gas separated into fresh air and burned gas in the compression stroke is rapidly mixed near the top dead center, thereby causing auto-ignition combustion. After the combustion and expansion strokes, part of the burned gas is exhausted in the gas exchange process, and fresh air is supplied instead. It should be noted that in an actual engine, a clear distribution of two regions as shown in FIG. 4 is not achieved, and it is needless to say that the distribution is not necessarily divided vertically.

FIG. 5 schematically shows the state in the cylinder intended by the present invention, taking a four-stroke cycle type internal combustion engine as an example. The gas separated into fresh air and burned gas in the compression stroke is rapidly mixed near the top dead center, thereby causing auto-ignition combustion. After the combustion and expansion strokes, a part of the burned gas is exhausted for a short period of time, and then waste compression and waste expansion are performed with the intake and exhaust valves closed. After the pressure in the cylinder has been sufficiently reduced, the intake valve is opened to supply fresh air into the cylinder. In an actual engine, it is natural that a clear distribution of two regions as shown in FIG. 5 is not achieved, and that the distribution does not necessarily need to be vertically divided.

In the four-stroke cycle internal combustion engine, by adjusting the opening timing of the intake and exhaust valves, the burned gas discharged to the intake passage or the exhaust passage in the exhaust stroke can be sucked in again in the intake stroke. Yes, if stratified intake is performed, the state in the cylinder intended by the present invention can be configured. However, in this case, since the temperature of the burned gas decreases, it is necessary to pay attention that the effect of promoting the self-ignition by the burned gas intended by the present invention is reduced.

[0029]

The present inventors have paid attention to the fact that auto-ignition combustion is strongly influenced by the reactivity and temperature of the air-fuel mixture and is promoted by adding radicals (active chemical species). Radicals are molecules that promote the chain of chemical reactions, and are generated in large quantities in the oxidation reaction process leading to self-ignition. Usually, in the process in which a combustible mixture reaches self-ignition in a high-temperature atmosphere, radicals are generated as a product of an initiation reaction typified by a direct reaction between fuel molecules and oxygen molecules. By reacting with, various molecules including radicals are generated, and finally the reaction progresses very quickly, leading to auto-ignition.

For example, when considering a saturated hydrocarbon as a fuel molecule, in the initiation reaction, a hydrogen atom in the fuel molecule is extracted by an oxygen molecule, and an alkyl radical and a HO2 radical each having one hydrogen atom missing from the fuel molecule are generated. . After that, many types of radicals such as OH and H are generated with the progress of the reaction, and they repeat the reaction with fuel molecules and alkyl radicals, and finally express self-ignition combustion with rapid heat generation, CO2 and The concentration of H2O changes to extremely high burned gas.

As described above, radicals can be said to be chemical species having the effect of promptly causing the self-ignition process to proceed. In the compression self-ignition combustion, the radicals are generated inside the combustible air-fuel mixture by the temperature rise due to compression. On the other hand, in the present invention, stable self-ignition near the top dead center is realized by supplying a high-temperature gas rich in radicals to the combustible air-fuel mixture from the outside near the top dead center.

In the present invention, a burned gas is used as a gas containing radicals to be supplied to the combustible mixture. Burned gas is generally a gas that has completed a major exothermic reaction, but its reaction does not stop because of its high temperature, and its generation and disappearance reactions are always repeated, and these reactions involve radicals. ing. That is, the burned gas contains many radicals. However, the chemical reaction in the burned gas becomes slower as the temperature decreases, and the radical concentration also decreases. In other words, when using burned gas as a source of radicals,
It is important to keep that temperature high.

The existence of the gas in the cylinder can be realized by conventional techniques such as increasing the residual gas using a variable valve timing mechanism and supplying EGR gas by recirculating exhaust gas (EGR). However,
When the burned gas is made to exist in the cylinder by these techniques, if it is sufficiently mixed with the newly supplied air by the early stage of the compression stroke, the radical concentration becomes extremely small due to the cooling by the air, Since the gas in the cylinder has a substantially uniform composition, turbulence near the top dead center has no meaning for the supply of radicals.

Therefore, it is important that the burned gas and air exist in the cylinder with distribution at least at the beginning of the compression stroke. That is, a region where the concentration of air is high and the temperature is relatively low (hereinafter abbreviated as air excess region) and a region where the concentration of the burned gas is high and the temperature is relatively high (hereinafter abbreviated as the air shortage region) exist. Is important. The intended states of the air-excess and air-deficient regions are shown in FIG.

Since the temperature of the air-deficient region is higher than that of the air-excess region, the temperature of the temperature increasing process accompanying the compression of the piston in the compression stroke is high, and the concentration of burned gas containing many radicals is high. , Can be unevenly distributed in the cylinder as a high-temperature and radical-rich gas mass.

On the other hand, since the temperature of the excess air region is lower than that of the insufficient air region, the temperature in the temperature rise process accompanying the compression of the piston in the compression stroke is low. There are few initial radicals.

Next, the relationship between the fuel molecules supplied into the cylinder and the radicals will be considered. The fuel molecules mixed in the excess air region are compressed for the above-mentioned reason without being substantially affected by radicals caused by the burned gas. On the other hand, the fuel molecules mixed in the air-deficient region decrease the temperature of the region where the fuel molecules are mixed by the latent heat of vaporization and reduce the radicals in the region. Will constitute the region.

That is, at least immediately after the fuel is supplied into the cylinder, the location where the fuel molecules are present has a condition in which there are few radicals and the temperature is relatively low. Therefore, the requirement of the present invention regarding the region where the fuel molecules are present is that at least at the beginning of the compression stroke, the fuel molecules are dispersed throughout the air deficient region, radicals in the entire air deficient region are reduced, and the temperature is lowered. Is to prevent it. That is,
An object is to form an air-deficient region having a low concentration of fuel molecules as well as air (hereinafter abbreviated as a burned gas excess region).
The intended state of the burnt gas excess region is shown in FIG.

In the burned gas excess region, as described above, since the air and fuel molecules are scarce, a high temperature and a state rich in radicals are formed in the compression stroke. On the other hand, in the air excess region or the air shortage region containing the fuel molecules (hereinafter, abbreviated as the fuel supply region), the oxidation reaction of the fuel molecules proceeds as the temperature increases in the compression stroke. However, under conditions where the oxidation reaction of the fuel supply region is relatively insufficient, that is, for example, when the compression ratio is insufficient, auto-ignition combustion cannot occur even after the top dead center.
In the prior art, this is a condition leading to misfire. The intended state of the fuel supply area is shown in FIG.

Therefore, in the present invention, turbulence is generated so that the burned gas excess region rapidly mixes with other regions in the cylinder near the top dead center. Due to this turbulence, a high-temperature, radical-rich gas is mixed into the fuel supply region, so that the chemical reaction of at least a part of the fuel molecules is accelerated to generate auto-ignition combustion. The self-ignition combustion generated in the cylinder causes a temperature rise by increasing the pressure in the cylinder, and this self-ignition combustion of other combustible air-fuel mixture, which was on the verge of self-ignition, immediately occurred. , Further increase the pressure in the cylinder. Due to this chain self-ignition combustion, in the prior art, even under conditions that lead to misfire,
Short-term combustion completion with high thermal efficiency is realized.

The squish portion claimed by the present invention has the effect of generating the turbulence near the top dead center. That is, in the latter half of the compression stroke, the gas in the vicinity of the squish portion is ejected to a wide area of the gap due to rapid reduction of the gap. Also, in the initial stage of the expansion stroke, rapid expansion of the gap causes rapid gas inflow from other regions. In other words, the squish portion disturbs the gas in the cylinder before and after the top dead center and mixes the above-described radical-rich high-temperature gas with the combustible air-fuel mixture to generate auto-ignition combustion near the top dead center. It has the effect of realizing quick completion.

FIG. 7 shows the case where the state in the cylinder intended by the present invention, that is, the state where the concentration of air and burned gas in the cylinder has a concentration distribution at least at the beginning of the compression stroke is realized in an actual engine. Is schematically shown. FIG. 7 assumes a configuration in which a combustible air-fuel mixture is supplied from an intake passage.

FIG. 8 schematically shows another example of the state in the cylinder intended by the present invention. An injection valve for directly injecting fuel into the cylinder is disposed above the cylinder, and fuel spray is present near the boundary between fresh air and burned gas.

[0044]

9 and 10 show an embodiment in which the present invention is realized as an overhead valve type two-stroke cycle type internal combustion engine equipped with a charge supercharger and a fuel injection valve for directly supplying fuel into a cylinder. Is shown. Referring to FIG. 9 and FIG.
Is an engine body, 2 is a cylinder block, 3 is a cylinder head, 4 is a piston, 5 is a combustion chamber, 6 is a mounting position of an electronically controlled fuel injection valve for directly injecting fuel into a cylinder, 8 is a supply valve, 9 Denotes an air supply port, 10 denotes an exhaust valve, and 11 denotes an exhaust port. The air supply port 9 is connected to the corresponding air supply branch 12
Connected to the surge tank 13 via the
3 is connected to an air cleaner 17 via an air supply duct 14, an air supply supercharger 15, and an air supply duct 16. The supercharger 15 is driven by an electric motor 18.

On the other hand, the exhaust port 11 is connected to an exhaust duct 20 via an exhaust manifold 19. Piston 4
A squish portion is formed near the exhaust valve 10 on the surface facing the cylinder head 3 so that the gap between the piston 4 and the cylinder head 3 is 1.5 mm at the top dead center. The area of the squish portion is configured to correspond to about 50% of the bore area including the exhaust valve portion.

The electronic control unit 50 is composed of a digital computer, and a ROM (read only memory) 52, a RAM (random access memory) 53, and a CPU (microprocessor) 5 connected to each other by a bidirectional bus 51.
4, an input port 55 and an output port 56 are provided. The output voltage of the required load sensor 61 that generates an output voltage proportional to the amount of depression of the accelerator pedal is output from the corresponding A / D converter 5.
7 to the input port 55. Further, the input port 55 is connected to a crank angle sensor 62 that generates an output pulse every time the crankshaft rotates, for example, by 10 °. The output form of the crank angle sensor may be any as long as it can calculate or express the rotational speed of the engine and the TDC and injection timing of each cylinder.

On the other hand, the output port 56 is connected to the electric motor 18 for driving the air-supercharger 15 via the corresponding drive circuit 58.
And an electronically controlled fuel injection valve installed at the mounting position 6 of the electronically controlled fuel injection valve.

FIG. 11 shows another embodiment. In this embodiment, the same components as those in the embodiment shown in FIG. 10 are denoted by the same reference numerals. The embodiment shown in FIG. 11 employs a system in which fuel is mixed with air supply and supplied into a cylinder. for that reason,
The fuel injection valve 7 is disposed in an air supply port 9 which is an air supply passage.

FIG. 12 shows the change in the rate of heat release with respect to the crank angle observed in an engine experiment. FIG.
In No. 2, the supplied fuel amount is fixed, and the supplied air amount is changed. Therefore, when the air supply amount increases, the A / F becomes lean.
Due to the strong disturbance generated near the top dead center, self-ignition after the top dead center is stably realized even with a change in the air-fuel ratio.

FIG. 13 shows the effect of the strong turbulence near the top dead center caused by squish on the stable occurrence of self-ignition. FIG. 13 shows the relative ignition amount (supply amount with respect to the ignition amount at top dead center (TDC)) regarding the self-ignition occurrence timing when the supplied fuel amount is fixed and the supplied air amount is changed in the engine experiment. Is compared on the horizontal axis. FIG.
3B shows the result when the effect of strong turbulence near the top dead center by the squish is not sufficient, and it can be understood that an increase in the supplied air amount easily causes a misfire. FIG. 13A shows the result under the condition that the effect of strong turbulence near the top dead center by the squish is sufficient, and misfire is unlikely to occur even when the supply air amount is increased. Indicates that combustion has been achieved.

In particular, since the change in the ignition timing before the misfire is small, it has been shown that highly efficient self-ignition combustion is realized in a wide range of air supply, and that there is a large margin for control and a transient. It can be expected that a misfire is unlikely to occur even under various operating conditions. It should be noted that the effects intended by the present invention can also be realized by a four-stroke cycle internal combustion engine, and it is obvious that various modifications can be made without departing from the technical idea of the present invention.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between a combustion start crank angle, a combustion period, and thermal efficiency obtained by numerical simulation.

FIG. 2 is a diagram showing a relationship between a combustion period, an air-fuel ratio, and a combustion start crank angle at which thermal efficiency is maximized, obtained by numerical simulation.

FIG. 3 is a diagram showing a change in ignition timing with respect to a change in air supply amount.

FIG. 4 is a schematic view showing a state in a cylinder intended by the present invention.

FIG. 5 is a schematic diagram showing a state in a cylinder intended by the present invention.

FIG. 6 is a diagram that defines abbreviations indicating states in a cylinder realized in the present invention.

FIG. 7 is a schematic diagram showing a state in a cylinder when the present invention is realized by an actual engine.

FIG. 8 is a schematic diagram showing a state in a cylinder when the present invention is realized by an actual engine.

FIG. 9 is an overall view of a two-stroke cycle type internal combustion engine claimed by the present invention.

FIG. 10 is a side sectional view of an engine body and an inner view of a cylinder head as viewed from a combustion chamber side.

FIG. 11 is a side sectional view of an engine body showing another embodiment and an inner view of a cylinder head viewed from a combustion chamber side.

FIG. 12 is a diagram of a heat release rate showing the effect of the present invention.

FIG. 13 is a diagram showing the relationship between the ignition timing and the amount of supplied air, which shows the effect of the present invention. FIG. 2 is a side cross-sectional view of a main body and an inner view of a cylinder head viewed from a combustion chamber side.

[Explanation of symbols]

4 ... Piston 5 ... Combustion chamber 6 ... Mounting position of an electronically controlled fuel injection valve that injects fuel directly into the cylinder 15 ... Charge supercharger

 ────────────────────────────────────────────────── ─── Continued on the front page F-term (reference)

Claims (7)

[Claims] 1. A compression ignition type or spark ignition type internal combustion engine characterized in that self-ignition combustion of a combustible air-fuel mixture is generated in all or part of a combustion process in one cycle. An internal combustion engine having a region in which a burned gas concentration is extremely high in a cylinder, and in which the gas in the cylinder is disturbed near a compression top dead center in the cylinder. 2. At least at the beginning of the compression stroke, there is a region in the cylinder where the burned gas concentration is extremely high, and the fuel supplied to the cylinder is applied only to a part of the region where the burned gas concentration is extremely high. 2. The internal combustion engine according to claim 1, wherein the internal combustion engine is present. 3. A fuel supply device is provided in a passage through which air supplied to a cylinder passes, and when the air, fuel and burned gas are charged into the cylinder, the air and the burned gas are filled. 3. The method according to claim 1, wherein mixing is suppressed.
An internal combustion engine according to any one of the preceding claims. 4. A fuel injection valve for directly supplying fuel spray to a cylinder, and mixing of the air and the burned gas is suppressed when the cylinder is filled with air and burned gas. 3. The internal combustion engine according to claim 1, wherein the fuel spray is not mixed with at least a part of the burned gas at the time of fuel supply. 4. 5. The volume ratio of the burned gas and air newly supplied into the cylinder during the compression stroke is determined by dividing the burned gas by 3
The internal combustion engine according to any one of claims 1 to 4, wherein the lower limit of the ratio of the air is 7 and the volume ratio of the burned gas is equal to or higher than the ratio. 6. The internal combustion engine according to claim 1, wherein a squish portion is formed in a part of the combustion chamber at a top dead center so that a gap is smaller than that of another part. 7. The internal combustion engine according to claim 6, wherein the area of the squish portion is not less than 25% and not more than 75% of the cylinder bore area, and the gap at the top dead center of the squish portion is not more than 3 mm.