JP2008088920A - Cylinder injection type spark ignition internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder injection type spark ignition internal combustion engine having improved combustion efficiency in a low load operation region during stratified charge combustion while suppressing the occurrence of smoke with the treatment of greatly delayed ignition for heating an exhaust gas purifying catalyst at starting. <P>SOLUTION: The spark ignition internal combustion engine comprises an injector 10 and an ignition plug 12 arranged near the ceiling center of a combustion camber 5, and a piston whose top face portion is formed into a recessed portion and divided with a partition wall shaped sorting protruded portion 14 protruded from a bottom face portion to construct an ignition stratified mixture flow forming cavity 15 which reflects a sprayed fuel flow 11 injected by the injector 10 to form stratified mixture over the ignition plug 12, and a homogeneous mixture forming cavity 16 which changes the sprayed fuel flow 11 distributed by the sorting protruded portion 14 into homogeneous mixture. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a mixture distribution state in which the air-fuel ratio of the mixture is locally varied in the combustion chamber in response to drastically changing and adjusting the timing of fuel injection directly supplying fuel into the combustion chamber. The present invention relates to an in-cylinder injection spark ignition internal combustion engine that can be ignited.

  In general, for an internal combustion engine (engine) used for automobiles and the like, in order to improve fuel consumption, the air-fuel ratio is locally rich in the combustion chamber, or an air-fuel mixture is formed only in a local portion, etc. Some combustion chambers use a stratified combustion method in which combustion is performed at a lean (oxygen-rich atmosphere) air-fuel ratio as a whole.

  This stratified combustion internal combustion engine has an in-cylinder injection method and a spark ignition method in which fuel is directly injected into the combustion chamber by an injector in order to accurately control the air-fuel ratio of the air-fuel mixture locally formed in the combustion chamber. Some have been adopted.

  Furthermore, in a cylinder-injection spark ignition internal combustion engine, a piston is provided with a cavity having a concave shape at a predetermined portion of the top surface, and fuel is injected by the injector into the cavity, thereby vaporizing the fuel. There are some which are configured to promote and to reduce the adhesion of fuel to the inner wall surface of the cylinder.

  In a conventional in-cylinder spark ignition internal combustion engine configured in this way, for example, a combustion chamber ceiling formed in a pent roof type (gable roof type) is formed in the cylinder head, and the position closer to the center of the combustion chamber ceiling For example, fuel is injected from the injector disposed at a predetermined position on the center side from the portion where the intake valve and the exhaust valve are disposed toward the axial direction of the cylinder at a predetermined timing.

  Further, the piston is provided with a cavity formed in an annular recess having a position substantially coaxial with the central axis in the injection direction of the injector.

  At the same time, at the position deviated from the center of the combustion chamber ceiling to the intake side, the spark plug is disposed in the combustion chamber so as to protrude obliquely with respect to the cylinder axial direction, and the piston comes to the top dead center position. In addition, it is configured to be able to ignite at a position displaced from the center of the inner upper part of the cavity toward the intake side.

  In the in-cylinder spark-ignition internal combustion engine configured as described above, in the compression stroke of the internal combustion engine in the middle / low load operation region in which stratified combustion is performed, the piston rising to the cylinder head side is in a predetermined position before top dead center. When it reaches, fuel is injected from the injector.

  Then, in this in-cylinder spark-ignition internal combustion engine, the injected fuel (injected fuel) is received in the cavity and guided by a circumferential groove portion having a substantially arc shape in cross section, and the direction and spread of the injected fuel spread. By being controlled, the distribution state of the substantially donut-shaped air-fuel mixture is formed, so that it is possible to prevent the sprayed fuel from diffusing toward the inner peripheral wall surface of the cylinder.

  Therefore, in the in-cylinder injection spark ignition internal combustion engine configured as described above, it is possible to prevent deterioration of combustion due to a cooling action caused by a part of the injected fuel directly colliding with the inner peripheral wall surface of the cylinder and smoldering of the plug. (For example, refer to Patent Document 1).

  Also, in such an in-cylinder spark ignition internal combustion engine, when the internal combustion engine is started, the catalyst bed temperature of the catalyst installed to purify the exhaust gas discharged from the internal combustion engine is changed from room temperature to activate the function of the catalyst. In order to increase the temperature rapidly to the temperature of the internal combustion engine, fuel is injected from the injector and ignited during the expansion stroke of the internal combustion engine, thereby reducing the combustion energy of the fuel consumed to rotate the internal combustion engine and reducing the exhaust gas. It has been put into practical use to perform a so-called greatly retarded ignition process for rapidly increasing the catalyst bed temperature by feeding it to the exhaust gas purification catalyst at a high temperature.

  In the case of performing a large retarded ignition process in an in-cylinder injection spark ignition internal combustion engine having a configuration in which an injector and a spark plug are arranged side by side at the central portion of the combustion chamber ceiling of the cylinder head as described above, in the expansion stroke When fuel is injected from the injector, the piston top surface cavity moves away from the combustion chamber ceiling (the piston top surface escapes from the injector), so the fuel sprayed from the injector escapes the piston. The operation of reflecting the light back to the top surface and returning it to the position of the spark plug becomes difficult.

  For this reason, in the case of performing a highly retarded ignition process in an in-cylinder spark ignition internal combustion engine in which an injector and a spark plug are arranged at the center of the cylinder head, the sprayed fuel immediately after being injected from the injector It will be necessary to ignite with a spark plug located close to the injector.

  In this case, since the spray flight distance from the injector to the spark plug becomes extremely short, there is not enough time for the sprayed fuel to vaporize and mix with air. As a result, the spark plug may become wet and smoldered, or the sprayed fuel in a rich state may be ignited to generate unburned hydrocarbons (HC) and smoke.

JP-A-11-107759 JP 2003-27945 A

  In view of the above-described points, the present invention suppresses the occurrence of smoke when performing a process of large retarded ignition for rapidly increasing the catalyst bed temperature of the exhaust gas purification catalyst at the start of the internal combustion engine. A new in-cylinder spark ignition internal combustion engine that can improve the combustion efficiency when fuel is sprayed and ignited during the compression stroke of the internal combustion engine in the middle / low load operation region in which combustion is performed. And

  A direct injection spark ignition internal combustion engine according to claim 1 of the present invention is a direct injection spark ignition internal combustion engine in which fuel is directly injected into a combustion chamber of a cylinder by an injector and ignited by an ignition plug to cause combustion. In an engine, the injector is arranged in the center of the ceiling of the combustion chamber, and is configured to inject a sprayed fuel flow obliquely from the injector toward the piston side in the cylinder, at a position adjacent to the injector on the ceiling of the combustion chamber. The spark plug is disposed, and a concave injection pattern changing cavity is formed on the top surface of the piston, and a partition wall-shaped distribution projection is formed so as to rise from the bottom surface of the injection pattern changing cavity. Divided into a cavity for generating an ignited stratified mixture and a cavity for generating a homogeneous mixture, and a sprayed fuel stream is injected from the injector at a predetermined time. Thus, the atomized fuel flow injected by the distributing projection is distributed and distributed to the cavity for generating the ignition stratified mixed air flow and the cavity for generating the homogeneous air mixed gas, and is formed by the cavity for generating the air stratified mixed air flow. The ignited stratified mixture and the homogeneous mixture formed by the cavity for generating the homogeneous mixture can be ignited by a spark plug, and an atomized fuel stream is injected from the injector at another predetermined timing to ignite the stratified mixture It is characterized in that it can be ignited by a spark plug in a state where a stratified mixture is formed on the spark plug by being reflected by a generation cavity.

  According to a second aspect of the present invention, in the in-cylinder injection spark-ignition internal combustion engine according to the first aspect, in the in-cylinder injection spark-ignition internal combustion engine, a retardation for increasing the catalyst bed temperature of the exhaust gas purification catalyst. When performing the ignition process, the sprayed fuel flow is injected from the injector at one predetermined timing and reflected by the cavity for generating the ignited stratified mixture airflow to form the stratified mixture applied to the spark plug. It is characterized by igniting with a plug.

  By configuring as described above, in order to rapidly increase the catalyst bed temperature of the exhaust gas purification catalyst at the time of starting the internal combustion engine, the timing of fuel injection is greatly changed and adjusted, and when performing the processing of a large retarded ignition, By reflecting the sprayed fuel flow injected from the injector at the ignition stratified mixture flow generation cavity, the stratified mixture is collected so as to be applied to the ignition plug, and the ignition is ignited by the ignition plug, so that the occurrence of smoke can be suppressed. . In addition, according to this configuration, when fuel is sprayed in the compression stroke of the internal combustion engine in the middle / low load operation region where stratified combustion is performed, the air-fuel ratio of the air-fuel mixture is locally varied in the combustion chamber to obtain an appropriate air-fuel mixture. Since ignition is performed after the state of distribution is reached, combustion efficiency can be improved by performing combustion using the air in the combustion chamber without waste.

  According to a third aspect of the present invention, in the in-cylinder spark-ignition internal combustion engine of the first aspect, a predetermined number in the radial direction from the predetermined number of fuel injection nozzle holes of the injector to the fan-shaped range. The present invention is characterized in that a spray fuel stream is injected and a spark plug is disposed between adjacent spray fuel streams.

  With the configuration as described above, in addition to the operation and effect of the invention of claim 1, the spark plug is made up of liquid fuel particles contained in the spray fuel in a large amount when the spray fuel flow directly hits the spark plug. Smoldering during wet ignition can be suppressed.

  According to the in-cylinder injection spark ignition internal combustion engine of the present invention, in order to rapidly increase the catalyst bed temperature of the exhaust gas purification catalyst at the start of the internal combustion engine, the timing of fuel injection is greatly changed and adjusted to greatly retard ignition ignition. Smoke can be suppressed during processing, and when the fuel is sprayed during the compression stroke of the internal combustion engine in the middle / low load operation region where stratified combustion is performed, the air-fuel ratio of the air-fuel mixture is locally reduced in the combustion chamber. Therefore, it is possible to improve the combustion efficiency by igniting after making the air-fuel mixture in an appropriate mixture distribution state.

  An embodiment of the present invention relating to an in-cylinder injection spark ignition internal combustion engine will be described with reference to FIGS.

  FIG. 1 is a schematic cross-sectional view showing a main part of a single cylinder provided in an in-cylinder spark-ignition internal combustion engine E. Reference numeral 1 denotes a cylinder bore (the cylinder bore 1 refers to an intake valve, an exhaust valve, and the like). (It shall mean the part which comprises the space enclosed by the provided combustion chamber part, the cylinder inner wall face, and the piston head.) 2 is a piston. The in-cylinder injection spark ignition internal combustion engine E can be configured as a multi-cylinder internal combustion engine or a single-cylinder internal combustion engine.

  In this in-cylinder injection spark ignition internal combustion engine E, the cylinder head 4 is disposed so as to close the end opening portion of the cylinder hole formed in the cylinder block 3, and the crankshaft (not shown) is disposed in the cylinder hole of the cylinder block 3. The piston 2 is configured to be able to reciprocate while maintaining airtightness.

  In the in-cylinder injection spark ignition internal combustion engine E, a combustion chamber 5 corresponding to the cylinder hole of the cylinder head 4 is provided. The combustion chamber 5 is formed in a so-called pent roof type. That is, the pent roof type combustion chamber ceiling portion of the combustion chamber 5 is formed in a gable roof shape having two slope portions that form an isosceles triangle having an obtuse angle in a side view.

  As shown in FIGS. 1 and 6, an opening portion 6 a that opens the end portions of two intake ports 6 that are air intake passages provided in the cylinder head 4 is formed on one inclined surface portion of the combustion chamber 5. Form. In addition, an intake valve 7 for opening or blocking each opening portion 6a is attached to each opening portion 6a of each intake port 6.

  Each intake valve 7 is operated by a valve operating device to perform an operation of opening or closing each opening portion 6a in synchronization.

  Further, an opening 8 a that opens the ends of the two exhaust ports 8, which are exhaust gas discharge passages provided in the cylinder head 4, is formed on the other inclined surface of the combustion chamber 5. Further, an exhaust valve 9 for opening or blocking the opening 8a of each exhaust port 8 is mounted. Each exhaust valve 9 is operated by a variable valve apparatus controlled by an internal combustion engine control system (not shown), and performs an operation of opening or closing each opening portion 8a in synchronization.

  At the center of the pent roof type combustion chamber ceiling of the combustion chamber 5 in the cylinder bore 1 of each cylinder (for example, a predetermined position on the center side from the portion where the intake valve and the exhaust valve are arranged), the direction toward the central axis H of the cylinder bore 1 The injector 10 is disposed so that the tip end portion is exposed in the cylinder bore 1. The injector 10 is controlled by an internal combustion engine control system, and directly injects fuel supplied from a fuel tank (not shown) by a pressure pump into the cylinder bore 1 by a required amount at a controlled required timing. Configure as follows. The injector 10 is provided with a plurality of (here, six) injection holes (not shown) for fuel injection at the tip thereof.

  As can be understood from FIGS. 1, 3, and 6, the injector 10 is symmetrical with respect to the center line N from the predetermined plurality of fuel injection holes toward the exhaust port 8 from the intake valve 7. In this manner, a predetermined plurality of sprayed fuel streams 11 are injected.

  That is, in this injector 10, as shown in FIG. 3, it is equally spaced in the radiation direction with respect to the semicircular (flat fan-shaped) range in which the two exhaust valves 9 are arranged from the injector 10 arranged in the center of the cylinder bore 1. Is configured to inject a predetermined plurality of sprayed fuel streams 11.

  In addition, in the injector 10, when the cylinder bore 1 is viewed in a longitudinal section as shown in FIG. 1, the injector 10 disposed at the center is directed in a direction opened by a predetermined angle S with respect to the center line H of the cylinder bore 1. It is configured to inject a predetermined plurality of sprayed fuel streams 11.

  As shown in FIGS. 1, 3, and 6, in this in-cylinder injection spark ignition internal combustion engine E, the center line H of the cylinder bore 1 extends from the distal end portion of the injector 10 attached to the center portion of the combustion chamber 5 of the cylinder bore 1. In contrast, the sprayed fuel flow 11 is injected into the flow of the air sucked in the intake stroke by injecting the six sprayed fuel flows 11 in a direction (an obliquely downward direction in FIG. 1) opened by an angle of 30 degrees with respect to the air flow. 11 can be put on and a good tumble flow can be formed. The direction in which the sprayed fuel flow 11 is injected from the injector 10 can be set by selecting a required direction along the direction of the tumble flow created in the cylinder bore 1.

  That is, when the injector 10 is configured as specifically shown in FIGS. 1, 3, and 6 described above, for example, when the internal combustion engine is rotated at high load and high speed (for example, 80% or more of the maximum load is rotated). (Several 4000 rpm or more) so that the air taken in when the intake valve 7 is opened in the intake stroke follows the flow of air that rapidly flows into the cylinder bore 1 from between the opening 6 a of the intake port 6 and the intake valve 7. The sprayed fuel stream 11 is injected from the injector 10.

  Therefore, in this in-cylinder injection spark ignition internal combustion engine E, the tumble that is accelerated and strengthened by the combined flow of the air flowing in the intake stroke in the cylinder bore 1 and the penetration force of the injected fuel injected from the injector 10. Can be ignited in a state where turbulence is present in the cylinder bore 1 while maintaining good until the ignition timing at the end of the compression stroke, so that the combustion speed is increased and the in-cylinder injection spark ignition internal combustion engine The performance of E can be improved.

  Further, in this injector 10, in addition to being configured to inject six sprayed fuel streams 11 from the tip thereof, the shape of the fuel spray can be set variously. For example, the sprayed fuel stream 11 is relatively thick. The fuel may be injected into a thin and substantially fan shape, or one sprayed fuel stream 11 may be solid, hollow conical, or solid columnar. In the injector 10, the fuel spray shape may be a relatively thin arc-shaped fuel spray shape by combining arc-shaped slit nozzle holes or a plurality of linear slit nozzle holes.

  As shown in FIGS. 1, 3 and 6, this in-cylinder injection spark ignition internal combustion engine E is close to the injector 10 disposed on the central axis H of the cylinder bore 1 and goes from the intake valve 7 to the exhaust valve 9. The spark plug 12 is disposed at a predetermined position on the center line N parallel to the direction.

  The spark plug 12 is installed so as to be inclined in the direction of the central axis H of the cylinder bore 1 so that an electrode portion which is an ignition portion provided at one end portion is exposed in a state of slightly protruding into the combustion chamber 5. .

  The spark plug 12 is supplied with a drive current at a required ignition timing from a plug drive circuit controlled by an internal combustion engine control system (not shown) so as to ignite by blowing an arc between the two electrodes with the required ignition energy. Constitute.

  Further, in this in-cylinder injection spark ignition internal combustion engine E, as shown in FIG. 3, the spark plug 12 is disposed at a predetermined position of the cylinder head 4 so that two electrodes are positioned between the adjacent sprayed fuel flows 11. Thus, the sprayed fuel flow 11 injected from the injector 10 is configured to suppress smoldering in a state where the sprayed fuel flow 11 directly hits the two electrodes of the spark plug 12 and gets wet with the liquid fuel.

  As shown in FIGS. 1 to 5, in the in-cylinder injection spark ignition internal combustion engine E, the flow of the sprayed fuel injected from the injector 10 on the top surface of the piston 2 that is reciprocally disposed inside the cylinder bore 1. An injection pattern changing cavity 13 is provided for changing the state so as to switch between two injection patterns.

  The injection pattern changing cavity 13 is configured as a substantially oval recess in a plan view as shown in FIG. As shown in FIGS. 1 to 5, the injection pattern changing cavity 13 is formed on a curved surface C that is recessed so that the inner peripheral side surface thereof has a substantially arcuate cross section.

  In the injection pattern changing cavity 13 configured as described above, the sprayed fuel injected into the injection pattern changing cavity 13 is guided by the curved surface C on the inner periphery surrounding the cavity, and the inside of the cylinder hole of the cylinder block 3. Since it reflects toward the direction which does not directly hit a wall surface, it can suppress that sprayed fuel adheres to the inner wall surface of the cylinder hole of the cylinder block 3, and remains without burning.

  Further, the injection pattern changing cavity 13 is provided with a sorting protrusion 14 at a predetermined position on the bottom surface corresponding to the lower side of the opening 8a of the exhaust port 8, and is formed in a generally W-shaped longitudinal section as a whole. .

  The distribution projection 14 is formed in a partition wall shape having a substantially triangular cross section at a predetermined height from a semicircular arc-shaped range extending on one side of the center line M passing through the injector 10 at the bottom surface of the injection pattern changing cavity 13. It is constructed integrally so that it is raised and connected at the same height.

  The height of the sorting projection 14 can be determined in accordance with the state of the sprayed fuel flow 11 injected from the injector 10 and is, for example, about half the depth of the injection pattern changing cavity 13. be able to.

  As shown in FIG. 1, in this in-cylinder spark-ignition internal combustion engine E, for example, when the piston 2 is at a crank angle of 60 degrees before top dead center in the compression stroke, the center line of the cylinder bore 1 from the injector 10 The front end portion of the sprayed fuel flow 11 injected in a direction opened by a predetermined angle S (30 degrees in this case) with respect to H is configured to hit the ridge line 14 </ b> A of the sorting protrusion 14.

  As shown in FIGS. 1, 2, and 4, in the injection pattern changing cavity 13, a curve formed by being divided from the sorting projection 14 to the curved surface C on the inner periphery surrounding the cavity on the exhaust port 8 side. A cavity 15 for generating an ignited stratified mixture air flow for reflecting the sprayed fuel to the electrode part side of the spark plug 12 and forming an optimum stratified mixture having good ignitability applied to the electrode part is constituted by the recess.

  Further, in this injection pattern changing cavity 13, homogeneous mixing for homogeneously mixing the sprayed fuel is performed by a curved concave portion formed by dividing from the distributing projection 14 to the inner peripheral curved surface surrounding the cavity on the intake port 6 side. A gas generating cavity 16 is formed. In the injection pattern changing cavity 13, the ignition stratified mixed airflow generating cavity 15 is formed smaller than the homogeneous mixture generating cavity 16.

  Next, operations and operations related to the injection pattern changing cavity 13 of the in-cylinder spark ignition internal combustion engine E configured as described above will be described.

  In the in-cylinder injection type spark ignition internal combustion engine E, the catalyst bed temperature of the catalyst installed for purifying the exhaust gas discharged from the in-cylinder injection type spark ignition internal combustion engine E is changed from the normal temperature to the catalyst at the cold start. In order to rapidly increase the temperature up to the temperature at which the function of the engine is activated, so-called large retarded ignition processing is performed.

  When performing the process of large retarded ignition in the in-cylinder injection spark ignition internal combustion engine E, as shown in FIG. 4, during the expansion stroke of the in-cylinder injection spark ignition internal combustion engine E, the ignition stratification of the piston 2 from the injector 10 An atomized fuel flow 11 is injected toward the cavity 15 for generating a mixed airflow.

  Then, the sprayed fuel flow 11 injected from the injector 10 disposed at the center of the ceiling portion of the combustion chamber 5 of the cylinder head 4 moves away from the ceiling portion of the combustion chamber 5 (the operation of the piston 2 escaping from the injector 10). It is reflected by the cavity 15 for generating the ignition stratified mixed airflow on the top surface of the piston 2 and is returned to the position of the spark plug 12.

  That is, in this operation, even if the action of reflecting the atomized fuel flow 11 is weakened because the direction in which the atomized fuel flow 11 travels is the same as the direction in which the cavity 15 for generating the ignition stratified mixed airflow of the piston 2 moves, the injector 10 Most of the sprayed fuel flow 11 injected from the fuel is injected toward the ignition stratified mixed airflow generating cavity 15, reflected so as to be bent at the recess of the ignition stratified mixed airflow generating cavity 15, and close to the ignition plug 12. Since they are collected and returned, a stratified mixture over the electrode portion of the spark plug 12 can be formed in a narrow area formed at a predetermined location in the cylinder bore 1.

  Therefore, in the in-cylinder spark-ignition internal combustion engine E, as described above, the ignition plug 12 is ignited with the optimal air-fuel mixture having good ignitability formed around the electrode portion of the ignition plug 12 and is good. The combustion energy of the fuel at this time is reduced to be consumed for rotating the in-cylinder injection spark ignition internal combustion engine E, and the exhaust gas is sent to the exhaust gas purification catalyst at a high temperature. The bed temperature can be increased rapidly.

  More specifically, in this in-cylinder spark-ignition internal combustion engine E, an appropriate timing for creating a state in which the sprayed fuel flow 11 is reflected by the cavity 15 for generating the ignition stratified mixed airflow (a crank angle suitable for this) The sprayed fuel flow 11 is injected from the injector 10 within the range of the second predetermined crank angle that is the timing of

  In the in-cylinder spark-ignition internal combustion engine E, the timing at which the stratified mixture is formed around the spark plug 12 by the reflected sprayed fuel flow 11 (for example, the crank angle is 60 degrees from the top dead center of the expansion stroke). The ignition timing is advanced at the above timing, preferably at a required timing in the range of about 70 to 80 degrees.

  In this way, in the case where the in-cylinder injection spark ignition internal combustion engine E performs the processing of the large retarded ignition, the injected fuel immediately after being injected from the injector 10 is applied to the spark plug 12 and the spark plug 12 gets wet and smoldering. And the generation of unburned hydrocarbons (HC) and smoke can be suppressed.

  Next, a description will be given of a case where stratified combustion is performed in the in-cylinder injection spark ignition internal combustion engine E during operation in the middle / low load operation region (for example, 80% or less of the maximum load and 4000 rpm or less).

  In this case, as shown in FIGS. 1 and 2, in the compression stroke of the in-cylinder spark-ignition internal combustion engine E that is operating in the middle / low load operation region, the injector 10 moves to the sorting protrusion 14 of the piston 2. A sprayed fuel stream 11 is injected toward the head.

  Then, the distribution protrusion of the piston 2 in which the sprayed fuel flow 11 injected from the injector 10 disposed at the center of the ceiling of the combustion chamber 5 of the cylinder head 4 approaches the ceiling of the combustion chamber 5 is performed. 14 is distributed at a predetermined distribution ratio (for example, 50 to 50) between the flow into the cavity 15 side for generating the ignition stratified mixed air flow and the flow into the cavity 16 side for generating the homogeneous air mixture. It is done.

  In this in-cylinder spark-ignition internal combustion engine E, by controlling the spray period during which the sprayed fuel stream 11 is injected from the injector 10, the sprayed fuel stream 11 is generated at the side of the cavity 15 for generating the ignition stratified mixed airflow at a required distribution rate. And the cavity 16 side for generating a homogeneous mixture.

  In this in-cylinder spark-ignition internal combustion engine E, for example, when the piston 2 moves to the top dead center side during the compression stroke, when the crank angle reaches 60 degrees before the compression top dead center, the injector 10 The injection operation is performed at the timing (within the range of the first predetermined crank angle) that is the final timing of the spray period in which the sprayed fuel flow 11 is injected.

  As a result, in the in-cylinder injection spark ignition internal combustion engine E, at the ignition timing shown in FIG. 2 that has reached the end of the compression stroke, it is guided by the sorting projection 14 and enters the cavity 16 for generating the homogeneous mixture. While the atomized fuel flows through a relatively long distance (longer than the cavity 15 for generating the ignited stratified mixed air flow), vaporization proceeds and mixing with a relatively large amount of air proceeds, resulting in a lean (oxygen-rich atmosphere). Form a homogeneous, weakly stratified mixture in a state.

  Further, in this in-cylinder spark-ignition internal combustion engine E, at the ignition timing shown in FIG. 2, the sprayed fuel that is guided by the sorting projection 14 and introduced into the cavity 15 for generating the ignition stratified mixed airflow is reflected. Then, it is vaporized and mixed with air to form a stratified mixture, and a part of this stratified mixture is applied to the electrode portion of the spark plug 12.

  Next, in this in-cylinder spark-ignition internal combustion engine E, an optimal stratified mixture with good ignitability (for example, formed around the electrode portion of the spark plug 12 on the side of the cavity 15 for generating the ignited stratified mixture airflow) The stoichiometric mixture (the stoichiometric air-fuel ratio) is ignited by the spark plug 12 and an initial flame is generated at the center of the cylinder bore 1.

  Then, the initial flame at the central portion of the cylinder bore 1 spreads the flame toward the ignition stratified mixed airflow generating cavity 15 side, and at the same time, the state where the initial flame is generated is shared. Ignites the weakly stratified air-fuel mixture at an air-fuel ratio leaner than the stoichiometric air-fuel ratio on the cavity 16 side, spreads the flame, and burns well in the cavity 16 for generating a homogeneous air-fuel mixture To do.

  Therefore, in the in-cylinder injection spark ignition internal combustion engine E, when an optimal stratified mixture having good ignitability is ignited by the spark plug 12 at the center of the cylinder bore 1 to generate an initial flame, the ignition is started from the initial flame. A flame propagates simultaneously to the cavity 15 side for generating the stratified mixture air flow and the cavity 16 side for generating the homogeneous mixture, and combustion in the entire interior of the combustion chamber 5 side can be performed in a relatively short period of time. (That is, the period can be shorter than when the flame is propagated from one end of the cavity to the other end).

  Further, in this in-cylinder injection spark ignition internal combustion engine E, the sprayed fuel flow 11 is injected from the injector 10 at the center of the cylinder bore 1 toward the injection pattern changing cavity 13 toward the ignition stratified mixed airflow generating cavity 15 side. Even so, for example, about half of the sprayed fuel flow 11 is reflected and filled into the space on the opposite side of the spraying direction of the sprayed fuel flow 11 by the sorting projection 14, so that the entire inside of the injection pattern changing cavity 13 is filled. It is possible to improve the combustion efficiency by using the air evenly.

  When sprayed fuel is injected only on one side of one shallow dish-shaped cavity, the air-fuel ratio becomes excessively richer than the stoichiometric air-fuel ratio, being biased toward one end of the cavity, and the other end of the cavity. As a result, it becomes too lean at the end of the cylinder, so that homogeneous combustion is impossible as a whole, and combustion efficiency is lowered.

  In comparison, the in-cylinder injection spark ignition internal combustion engine E provided with the injection pattern changing cavity 13 can improve the combustion efficiency.

  Next, when the high-load high-rotation operation is performed in the in-cylinder injection spark ignition internal combustion engine E, as described above, the flow of air rapidly flowing into the cylinder bore 1 from the intake valve 7 opened in the intake stroke, and the injector In combination with the penetrating force of the sprayed fuel flow 11 injected from 10, it can be accelerated and strengthened to form a strong tumble flow, so that the combustion speed can be increased and the performance of the direct injection spark ignition internal combustion engine E can be improved. .

  In addition, this invention is not limited to embodiment mentioned above, Of course, in the range which does not deviate from the summary of this invention, other various structures can be taken.

According to an embodiment of an in-cylinder injection spark ignition internal combustion engine of the present invention, a main part of one cylinder is taken out, and a sprayed fuel flow from an injector is changed into an injection pattern changing cavity during middle / low load operation in which stratified combustion is performed It is a cross-sectional schematic block diagram which shows the state injected to the distribution protrusion part. 1 is a schematic cross-sectional configuration diagram showing a state in which a main part of one cylinder is taken out and ignited for stratified combustion during medium / low load operation according to an embodiment of an in-cylinder injection spark ignition internal combustion engine of the present invention; . 1 is a schematic plan view showing a piston portion in one cylinder according to an embodiment of a direct injection spark ignition internal combustion engine of the present invention. According to the embodiment of the in-cylinder injection spark ignition internal combustion engine of the present invention, the main part of one cylinder is taken out, and the ignition stratified mixed air flow from the injector to the piston is performed at the time of start-up to perform the process of greatly retarded ignition in the expansion stroke It is a cross-sectional schematic block diagram which shows the state which injected the atomized fuel flow into the production | generation cavity. It is a perspective view which takes out and shows the part of the piston which concerns on embodiment of the cylinder injection type spark ignition internal combustion engine of this invention. It is a bottom view which shows the combustion chamber side of the cylinder head based on Embodiment of the cylinder injection type spark ignition internal combustion engine of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder bore 2 Piston 3 Cylinder block 4 Cylinder head 5 Combustion chamber 6 Intake port 7 Intake valve 8 Exhaust port 9 Exhaust valve 10 Injector 11 Spray fuel flow 12 Spark plug 13 Injection pattern change cavity 14 Sorting protrusion 15 Ignition stratified mixed air flow generation Cavity 16 Cavity for Homogeneous Mixture Generation

Claims (3)

In a cylinder injection spark ignition internal combustion engine in which fuel is directly injected into a combustion chamber of a cylinder by an injector and is ignited by a spark plug to cause combustion.
The injector is disposed in the center of the ceiling of the combustion chamber, and is configured to inject a sprayed fuel flow from the injector toward the piston side in the cylinder in a slanted manner.
The spark plug is disposed at a position adjacent to the injector in the ceiling of the combustion chamber,
Forming a concave injection pattern changing cavity on the top surface of the piston;
A partition wall-shaped distribution projection is formed so as to protrude from the bottom surface of the injection pattern changing cavity, and is divided into a cavity for generating an ignition stratified mixed gas flow and a cavity for generating a homogeneous gas mixture,
By injecting the atomized fuel flow from the injector at a predetermined time, the atomized fuel flow injected by the sorting protrusion is used to generate the ignition stratified mixed airflow generation cavity and the homogeneous mixture generation cavity. The ignition plug can ignite the stratified mixture formed by the cavity for generating the ignited stratified mixture and the homogeneous mixture formed by the cavity for generating the homogeneous mixture. Configure
It is possible to ignite with the spark plug in a state where a stratified mixture is formed on the spark plug by injecting the atomized fuel flow from the injector at another predetermined time and reflecting it at the ignition stratified mixed air flow generation cavity. An in-cylinder injection spark ignition internal combustion engine characterized by comprising:   In the in-cylinder injection spark ignition internal combustion engine, when performing the retarded ignition process for increasing the catalyst bed temperature of the exhaust gas purification catalyst, the sprayed fuel flow is injected from the injector at one predetermined timing. 2. The in-cylinder injection type according to claim 1, wherein the ignition plug is ignited in a state in which the stratified mixture applied to the spark plug is formed by being reflected by the ignition stratified mixture air flow generation cavity. Spark ignition internal combustion engine.   A predetermined plurality of sprayed fuel flows are injected in a radial direction with respect to a fan-shaped range from a plurality of fuel injection nozzle holes of the injector, and at positions between adjacent sprayed fuel flows, The in-cylinder injection spark ignition internal combustion engine according to claim 1, wherein the ignition plug is disposed.

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