JP2013036342A - Fuel injection control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection control device that can suppress oil dilution or smoke generation by focusing on ascending current or descending current out of air current generated in a combustor, suppressing the effect of the ascending and descending currents on an injected fuel, and reducing fuel adhesion to a cylinder wall surface or a piston top.SOLUTION: An electronic control device 30, which is the fuel injection control device, changes an injection angle of fuel that is injected into the combustor 11 by controlling a fuel injection valve 18 which can change the injection angle of the fuel. When the electronic control device 30 injects the fuel during its intake stroke, it declines the injection angle of the fuel toward an intake valve 24, especially when the fuel is injected when a flow rate of the air, which is flown into the combustor 11 from a gap between the opened intake valve 24 and a valve seat, is faster.

Description

  The present invention relates to a fuel injection control device for controlling fuel injection in a direct injection internal combustion engine.

A direct injection internal combustion engine that directly injects fuel into a combustion chamber is characterized by a high degree of freedom in the formation of an air-fuel mixture in the combustion chamber.
For example, a stratified mixture can be formed so that a mixture with a high fuel concentration is formed around the spark plug and a mixture with a low fuel concentration is formed around the spark plug. If such a stratified mixture is formed during low-load operation, combustion at a lean air-fuel ratio becomes possible, so it becomes possible to perform low-load operation with the throttle valve wide open, and pumping loss is reduced. . In addition, when such a stratified mixture is ignited, an air layer is formed between the combustion gas and the cylinder wall surface, so that the temperature reduction of the combustion gas is suppressed by the heat insulation effect, and the cooling loss is reduced. . Therefore, in a direct injection internal combustion engine, fuel efficiency can be improved by forming a stratified mixture and burning it.

  On the other hand, in a cylinder injection internal combustion engine, since fuel and air are mixed in the combustion chamber, the injected fuel easily collides with the cylinder wall surface or the piston top surface. Further, the time until the injected fuel is vaporized is shorter than that of the port injection type internal combustion engine.

  When the fuel injected into the cylinder collides with the cylinder wall surface and the fuel adheres to the cylinder wall surface, the adhering fuel and the engine oil are mixed and the engine oil is diluted. Also, if the fuel injected into the cylinder collides with the piston top surface and the fuel adheres to the piston top surface, the concentration of the air-fuel mixture increases locally, soot is generated by combustion of the over-concentrated portion, and smoke The amount generated increases. In particular, when the amount of fuel injection is large, such as during low-temperature start-up or high-load operation, the fuel is difficult to vaporize, so the above tendency becomes stronger. Furthermore, when the air flow in the combustion chamber is strong, the air-fuel mixture is caused to flow by the air flow generated in the combustion chamber, and the fuel easily adheres to the cylinder wall surface or the piston top surface.

  On the other hand, the fuel injection control device described in Patent Document 1 is provided with a plurality of injection ports for injecting fuel in the fuel injection valve, and appropriately switches the injection ports to be used. And in this patent document 1, the shape of the fuel spray formed by the injected fuel is changed so as to cancel the influence of the swirling flow such as swirl and tumble by switching the injection port to be used.

  Thus, if the shape of the fuel spray is changed so as to counteract the swirl flow such as swirl or tumble, the injected fuel is greatly flowed even if the air flow (swirl flow) is excessive. This can be suppressed, and the fuel adhesion to the cylinder wall surface and the piston top surface can be reduced.

JP 2011-7046 A

  By the way, in the invention described in Patent Document 1, attention is paid to swirling flow such as swirl and tumble in the air flow generated in the combustion chamber, and the fuel adhesion to the cylinder wall surface and the piston top surface due to this is reduced. I have to. However, in addition to swirling flow such as swirl and tumble, ascending and descending airflows are generated in the combustion chamber, and these ascending and descending airflows also promote fuel adhesion to the cylinder wall surface and piston top surface. .

  For example, when fuel is injected during the intake stroke as shown in FIG. 12, the air flows into the combustion chamber 91 through the gap between the opened intake valve 90 and the valve seat, and as shown by the arrow Airflow is generated. Therefore, when the fuel is injected toward the region Z3 as indicated by the one-dot chain line to reach the region Z3 indicated by the broken line in FIG. 12, as indicated by the white arrow in FIG. In other words, the fuel injected due to the influence of the downward airflow will flow downward. If the injected fuel is caused to flow downward, the fuel cannot reach the region Z3, and the fuel easily reaches the top surface of the piston 92, as shown in the center of FIG. The fuel tends to adhere to the top surface of the piston 92.

  In addition, when fuel is injected during the compression stroke as shown in FIG. 13, ascending airflow is generated in the combustion chamber as indicated by the arrow as the piston 92 rises. Therefore, when the fuel is injected toward the region Z4 as indicated by the one-dot chain line in order to reach the region Z4 indicated by the broken line in FIG. 13, as indicated by the white arrow in FIG. In other words, the injected fuel is caused to flow upward due to the influence of the updraft. If the fuel thus injected flows upward, the fuel cannot reach the region Z4, and the wall surface of the cylinder 93 is opposite to the position where the fuel injection valve is provided. As shown in the right side of FIG. 13, the fuel easily adheres to the wall surface of the cylinder 93.

  However, the invention described in Patent Document 1 does not focus on the updraft or downdraft generated in the combustion chamber. Therefore, depending on the invention described in Patent Document 1, there is a possibility that fuel adhesion to the wall surface of the cylinder and the top surface of the piston due to the updraft and downdraft generated in the combustion chamber cannot be sufficiently suppressed.

  The present invention has been made in view of the above circumstances, and its purpose is to focus on the rising airflow or the downward airflow among the air flow generated in the combustion chamber, and to suppress the influence of these on the injected fuel. Another object of the present invention is to provide a fuel injection control device capable of suppressing oil dilution and smoke generation by reducing fuel adhesion to the piston top surface.

In the following, means for achieving the above object and its effects are described.
According to the first aspect of the present invention, the fuel injection control of the direct injection internal combustion engine that changes the injection angle of the fuel injected into the combustion chamber by controlling the fuel injection valve capable of changing the injection angle of the fuel. When the fuel is injected during the intake stroke, the more the fuel is injected when the flow velocity of the air flowing into the combustion chamber through the gap between the opened intake valve and the valve seat is high, the more the fuel is injected. The gist is to incline the injection angle toward the intake valve.

  In the intake stroke, air flows from the intake port through the gap between the intake valve and the valve seat as the intake valve opens. Therefore, a downdraft is generated in the combustion chamber due to the inflow of air during the intake stroke. The fuel injected into the combustion chamber is affected by the downdraft and diffuses to flow toward the piston. That is, the fuel injected from the fuel injection valve is deflected to the piston side under the influence of the downdraft. As a result, the injected fuel is likely to adhere to the piston top surface.

  On the other hand, according to the configuration of the first aspect, as the fuel is injected when the flow velocity of the air flowing into the combustion chamber through the gap between the intake valve and the valve seat is faster, the fuel injection angle becomes the intake air. Tilt to the valve side. That is, since the fuel is injected in a state inclined in advance toward the upstream side of the downdraft, even if the injected fuel is deflected to the piston side due to the influence of the downflow, the injected fuel is An excessive approach to the top surface can be suppressed.

  In addition, since the flow rate of the air flowing into the combustion chamber through the gap between the intake valve and the valve seat is faster and the injected fuel is more likely to flow to the piston side by the downdraft, the fuel injection angle is inclined toward the intake valve side. By changing the injection angle according to the magnitude of the influence of the downdraft on the injected fuel, the influence of the downdraft on the injected fuel can be suitably suppressed.

  In short, according to the first aspect of the present invention, by suppressing the influence of the downdraft on the injected fuel among the air flow generated in the combustion chamber, and reducing fuel adhesion to the piston top surface, The occurrence of smoke can be suppressed.

  According to a second aspect of the present invention, in the fuel injection control device according to the first aspect, when the fuel is injected at the initial stage of the intake stroke when the intake valve starts to open, the amount by which the fuel injection angle is inclined toward the intake valve side. The gist is to reduce the amount by which the fuel injection angle is inclined toward the intake valve as the fuel is injected later in the intake stroke.

  At the beginning of the intake stroke when the intake valve begins to open, the pressure difference between the intake port side and the combustion chamber side is large, and air flows into the combustion chamber with a small lift amount of the intake valve. In particular, the flow velocity of air flowing in through the gap becomes faster. Therefore, as described in claim 1, a configuration is realized in which the fuel injection angle is inclined toward the intake valve side as the fuel is injected when the flow velocity of the air flowing from the gap between the intake valve and the valve seat is fast. For this purpose, as described in claim 2 above, when fuel is injected at the beginning of the intake stroke when the intake valve starts to open, the amount of inclination of the fuel injection angle toward the intake valve is maximized, The amount by which the fuel injection angle is inclined toward the intake valve may be reduced as the fuel is injected later in the stroke.

  According to the configuration described in claim 2 above, when the fuel is injected at the initial stage of the intake stroke in which the flow velocity of the air flowing into the combustion chamber through the gap between the intake valve and the valve seat becomes particularly fast, the fuel injection angle is set. The amount of inclination to the intake valve side is maximized, and the injection angle can be set in accordance with the magnitude of the influence of the downdraft.

  According to a third aspect of the present invention, the fuel injection control of a direct injection internal combustion engine that changes the injection angle of the fuel injected into the combustion chamber by controlling the fuel injection valve capable of changing the fuel injection angle. When the fuel is injected during the compression stroke, the fuel injection angle is tilted toward the piston as the fuel is injected when the flow rate of the rising air flow generated in the combustion chamber is high as the piston rises. This is the gist.

  In the compression stroke, an updraft is generated in the combustion chamber as the piston rises. The fuel injected into the combustion chamber is affected by this updraft and diffuses so as to be pushed up toward the top surface of the combustion chamber to which an intake valve, an exhaust valve, and a spark plug are attached. That is, the fuel injected from the fuel injection valve is deflected away from the piston under the influence of the upward airflow. As a result, the injected fuel is likely to adhere to the cylinder wall surface located on the opposite side of the position where the fuel injection valve is attached.

  On the other hand, according to the configuration of the third aspect, the fuel injection angle becomes closer to the piston side as the fuel is injected when the flow rate of the rising air flow generated in the combustion chamber is faster as the piston is raised. Tilted. That is, since the fuel is injected in a state inclined in advance toward the upstream side of the updraft, even if the injected fuel is deflected away from the piston under the influence of the updraft, the injected fuel Can be prevented from excessively approaching the cylinder wall surface.

  Also, as the flow rate of the updraft generated in the combustion chamber as the piston rises is high, and the injected fuel tends to flow toward the top surface of the combustion chamber by the updraft, the fuel injection angle is inclined toward the piston side. Therefore, the injection angle can be changed according to the magnitude of the influence of the updraft on the injected fuel, and the influence of the updraft on the injected fuel can be suitably suppressed.

  In short, according to the third aspect of the present invention, the influence of the updraft on the injected fuel among the air flows generated in the combustion chamber is suppressed, and the fuel adhesion to the cylinder wall surface is reduced. Dilution can be suppressed.

  According to a fourth aspect of the present invention, in the fuel injection control device according to the third aspect, when the fuel is injected during the compression stroke, the fuel is injected as the fuel is injected when the rising speed of the piston is high. The gist is to incline the angle toward the piston.

  The flow rate of the ascending airflow generated as the piston rises in the compression stroke is proportional to the ascending speed of the piston. The higher the ascending speed of the piston, the faster the ascending airflow velocity. Therefore, as described in claim 3, a configuration is realized in which the fuel injection angle is inclined toward the piston as the fuel is injected when the flow rate of the ascending air flow generated in the combustion chamber is high as the piston is raised. For this purpose, the fuel injection angle may be inclined toward the piston as the fuel is injected when the ascending speed of the piston is high as described in claim 4.

  According to the configuration described in claim 4, the fuel injection angle is inclined toward the piston side as the piston ascending speed is fast and the flow rate of the ascending air flow generated in the combustion chamber with the piston ascending is fast. Thus, the injection angle can be set in accordance with the magnitude of the influence of the rising airflow.

  According to a fifth aspect of the present invention, in the fuel injection control device according to the third aspect, when the fuel is injected in the middle of the compression stroke, the amount by which the injection angle is inclined to the piston side is maximized, and the initial stage of the compression stroke and When the fuel is injected in the latter period, the gist is to reduce the amount by which the injection angle is inclined toward the piston side, compared to the case where the fuel is injected in the middle period of the compression stroke.

  The piston connected to the crankshaft via the connecting rod has the highest rising speed in the middle of the compression stroke. Therefore, as described in claim 3, a configuration is realized in which the fuel injection angle is inclined toward the piston as the fuel is injected when the flow rate of the ascending air flow generated in the combustion chamber is high as the piston is raised. For this purpose, as described in claim 5 above, when fuel is injected in the middle of the compression stroke, the amount by which the injection angle is inclined to the piston side is maximized, and fuel is injected in the early and late stages of the compression stroke. In this case, the amount of tilting the injection angle toward the piston may be smaller than that in the case where fuel is injected in the middle of the compression stroke.

  According to the fifth aspect of the present invention, the fuel injection angle is the largest in the middle of the compression stroke in which the ascending speed of the piston is fast and the flow velocity of the ascending air flow generated in the combustion chamber increases as the piston rises. The injection angle can be set in accordance with the magnitude of the influence of the updraft.

  According to a sixth aspect of the present invention, in the fuel injection control device according to the second or fifth aspect, the amount of tilting of the fuel injection angle is increased as the engine rotational speed when fuel is injected is higher. The gist.

  The higher the engine speed, the higher the flow rate of air flowing into the combustion chamber through the gap between the intake valve and the valve seat in the intake stroke. Therefore, the higher the engine rotation speed, the higher the flow rate of the downdraft generated in the combustion chamber during the intake stroke.

  Also, the higher the engine speed, the faster the piston rise speed during the compression stroke. Accordingly, the higher the engine speed, the higher the flow rate of the updraft generated in the combustion chamber during the compression stroke.

  According to the configuration described in claim 6, the higher the engine rotational speed, the greater the amount by which the fuel injection angle is tilted. Therefore, the engine rotational speed is high, and the flow rate of the ascending or descending airflow generated in the combustion chamber is high. Even if it is a case, the influence by these updrafts or downdrafts can be suppressed by increasing the amount which inclines an injection angle according to it.

In other words, the fuel injection angle can be set so as to cancel out the change in the magnitude of the influence by taking into account the change in the magnitude of the influence of the air flow due to the change in the engine rotation speed.
A seventh aspect of the present invention is the fuel injection control device according to any one of the first to sixth aspects, wherein the fuel injection angle is lower as the injection pressure of fuel injected from the fuel injection valve into the combustion chamber is lower. The gist of the invention is to increase the amount of tilting, while decreasing the amount of tilting of the fuel as the injection pressure of fuel injected from the fuel injection valve into the combustion chamber is higher.

The lower the injection pressure of the fuel injected into the combustion chamber, the lower the penetration force of the injected fuel, and the injected fuel is more susceptible to the air flow in the combustion chamber.
According to the above configuration, the amount by which the fuel injection angle is inclined is increased as the fuel injection pressure is lower, while the amount by which the fuel injection angle is inclined is decreased as the fuel injection pressure is higher. . Therefore, the fuel injection angle can be set so as to cancel the change in the magnitude of the influence by taking into account the change in the magnitude of the influence of the air flow due to the change in the fuel injection pressure.

  The invention according to claim 8 is the fuel injection control device according to any one of claims 1 to 7, wherein when the fuel injection amount injected by the fuel injection valve is equal to or greater than a specified value, fuel injection is performed. The gist is to inject fuel without tilting the angle.

  The smaller the amount of fuel injected into the combustion chamber, the lower the ratio of the amount of fuel to the amount of air present in the combustion chamber. Further, the smaller the amount of fuel injected into the combustion chamber, the lower the penetration force of the injected fuel. Therefore, the smaller the injection amount of the fuel injected into the combustion chamber, the more easily the injected fuel is affected by the air flow in the combustion chamber. On the other hand, when the amount of fuel injected into the combustion chamber is large, the ratio of the amount of fuel to the amount of air present in the combustion chamber is high, and the injected fuel has a high penetration force. Is less susceptible to air flow in the combustion chamber.

  According to the eighth aspect of the present invention, when the fuel injection amount is equal to or greater than the specified amount, the fuel is injected without tilting the fuel injection angle. For this reason, when the fuel injection amount is large and the injected fuel is not easily affected by the air flow in the combustion chamber, the injection angle is not inclined to the piston side or the intake valve side, and the fuel is kept at the normal injection angle. Will be injected. Therefore, it is possible to prevent the fuel injection angle from being tilted unnecessarily.

The schematic diagram which shows the relationship between the electronic control apparatus which is one Embodiment of the fuel-injection control apparatus of this invention, and the internal combustion engine which is the control object of the same electronic control apparatus. (A), (B), (C) is a schematic diagram explaining the relationship between the operation mode of the fuel injection valve which the electronic control apparatus concerning the embodiment controls, and the injection angle of a fuel. 6 is a flowchart showing a flow of correction amount setting processing executed by the electronic control apparatus according to the embodiment. (A), (B), (C), and (D) are intake stroke correction amount maps referred to in the correction amount setting processing. (A), (B), (C), (D) are correction amount maps for the compression stroke referred to in the correction amount setting process. The schematic diagram which shows the state of the fuel at the time of injecting a fuel during an intake stroke through the fuel-injection control which the electronic control apparatus concerning the embodiment performs. The schematic diagram which shows the state of the fuel at the time of injecting a fuel during a compression stroke through the fuel-injection control which the electronic control apparatus concerning the embodiment performs. The flowchart which shows the flow of the correction amount setting process as a 1st modification. The flowchart which shows the flow of the correction amount setting process as a 2nd modification. (A) is a map showing the relationship between the engine speed and the increase in the in-cylinder airflow speed. (B) is a map showing the relationship between the increase amount of the correction amount set through the correction amount setting process as the second modification and the engine speed. (A) is a map which shows the relationship between engine speed, engine cooling water temperature, and fuel injection pressure. (B) is a map showing the relationship between the engine speed and the engine coolant temperature and the correction amount of the fuel injection angle. The schematic diagram for demonstrating the influence of the downdraft with respect to the injected fuel. The schematic diagram for demonstrating the influence of the updraft with respect to the injected fuel.

Hereinafter, an embodiment in which a fuel injection control device according to the present invention is embodied as an electronic control device that comprehensively controls an internal combustion engine mounted on a vehicle will be described with reference to FIGS.
As shown in FIG. 1, a piston 12 is accommodated in the cylinder 10 of the internal combustion engine 1 so as to be able to reciprocate. The piston 12 is connected to a crankshaft (not shown) via a connecting rod 14. As the piston 12 is accommodated in the cylinder 10 in this way, the combustion chamber 11 is defined by the inner wall of the cylinder 10 and the top surface of the piston 12.

  Although only one combustion chamber 11 is shown in FIG. 1 for convenience of explanation, the internal combustion engine 1 is a multi-cylinder internal combustion engine having a plurality of combustion chambers 11. Since the configuration of the other combustion chamber 11 (not shown) is the same as that of the combustion chamber 11 shown in FIG. 1, the description of the other combustion chamber 11 (not shown) is omitted here.

  A spark plug 16 is attached to the upper part of each combustion chamber 11 so that the tip of the combustion chamber 11 is exposed in the combustion chamber 11. Further, an intake port 20 and an exhaust port 22 are connected to each combustion chamber 11. An intake valve 24 that communicates or shuts off the intake port 20 and the combustion chamber 11 is provided at a portion where the intake port 20 and the combustion chamber 11 are connected. Further, an exhaust valve 26 for connecting or blocking the exhaust port 22 and the combustion chamber 11 is provided at a portion where the exhaust port 22 and the combustion chamber 11 are connected.

  The intake valve 24 and the exhaust valve 26 are urged in the valve closing direction by a valve spring (not shown). The intake valve 24 is opened by the action of an intake camshaft connected to a crankshaft via a timing chain (not shown), and the exhaust valve 26 is an action of an exhaust camshaft connected to the crankshaft via a timing chain. Therefore, the valve is opened.

Further, as shown in the center of FIG. 1, a fuel injection valve 18 that directly injects fuel into the combustion chamber 11 is attached in the vicinity of the intake valve 24 on the wall surface of each cylinder 10.
The intake air amount control for adjusting the amount of air introduced into the combustion chamber 11, the fuel injection control by controlling the opening and closing of the fuel injection valve 18, the ignition timing control by controlling the spark plug 16, etc. 1 is executed by an electronic control unit 30 that controls 1 centrally.

  The electronic control unit 30 temporarily stores a central processing unit (CPU) that executes arithmetic processing related to these various controls, a read-only memory (ROM) that stores control programs and data, and results of the arithmetic processing. And a random access memory (RAM) stored in the memory.

Various sensors for detecting the state of each part of the internal combustion engine 1 and the state of each part of the vehicle are connected to the electronic control unit 30.
For example, the crank position sensor 31 outputs a pulse signal at every predetermined rotation angle as the crankshaft rotates. The cam position sensor 32 outputs a pulse signal for each predetermined rotation angle as the intake camshaft that drives the intake valve 24 and the exhaust camshaft that drives the exhaust valve 26 rotate. Based on the pulse signals output from the crank position sensor 31 and the cam position sensor 32, the electronic control unit 30 determines whether each cylinder 10 corresponds to an intake stroke, a compression stroke, a combustion stroke, or an exhaust stroke. To do. Further, the electronic control unit 30 calculates an engine rotation speed that is a rotation speed of the crankshaft based on the pulse signal output from the crank position sensor 31.

  The accelerator position sensor 33 detects the amount of accelerator operation by the driver. The vehicle speed sensor 34 detects the vehicle speed based on the rotational speed of the wheels. The water temperature sensor 35 detects the temperature of engine cooling water circulating in a water jacket provided in the internal combustion engine 1. The fuel pressure sensor 36 detects a fuel injection pressure that is the pressure of the fuel supplied to the fuel injection valve 18.

The electronic control unit 30 reads the detection signals from these various sensors 31 to 36 and executes various arithmetic processes related to the control of the internal combustion engine 1.
For example, the electronic control unit 30 estimates the magnitude of torque required based on the accelerator operation amount and the vehicle speed, adjusts the intake air amount, and generates torque commensurate with the required torque magnitude. The fuel injection amount is set as follows. Then, the opening / closing timing of the fuel injection valve 18 provided in each cylinder 10 is set based on the engine rotational speed, the fuel injection pressure, and the like, and the opening / closing is performed based on the pulse signal output from the crank position sensor 31 or the cam position sensor 32. When the time has come, the fuel injection valve 18 is opened and closed to inject a set amount of fuel.

  The electronic control unit 30 according to the present embodiment changes the fuel injection timing according to the operating state of the internal combustion engine 1 to inject fuel during the intake stroke or inject fuel during the compression stroke. Further, the ignition timing is also adjusted by controlling the spark plug 16 together with the control of the intake air amount and the fuel injection amount.

  The fuel injection valve 18 can change the fuel injection angle, and the electronic control unit 30 according to the present embodiment controls the fuel injection valve 18 through the fuel injection control. The injection angle of the fuel injected into the combustion chamber 11 is adjusted.

Next, the internal structure of the fuel injection valve 18 and a method for changing the fuel injection angle by controlling the fuel injection valve 18 will be described with reference to FIG.
As shown in FIGS. 2A, 2 </ b> B, and 2 </ b> C, the fuel injection valve 18 is provided with a first reservoir 80 in which the first needle 60 is accommodated. The first flow path 70 is connected to the first storage section 80 via the second storage section 82. The first flow path 70 communicates with an injection port 50 provided at the tip of the fuel injection valve 18, and the injection port 50 is provided with a curved portion 52 that curves so as to enlarge the opening area of the injection port 50. It has been.

  The first needle 60 is slidably accommodated in the first reservoir 80, and is seated on the valve seat portion to which the first reservoir 80 and the second reservoir 82 are connected. The communication between 80 and the second reservoir 82 is blocked.

  2A, 2B, and 2C, the fuel injection valve 18 includes a second flow path 72 that branches from the second storage portion 82 in addition to the first flow path 70. Is provided. The second flow path 72 communicates with the first flow path 70 from the side so as to open at a position facing the curved portion 52 in the injection port 50. A third reservoir 84 is provided in the middle of the second flow path 72, and a second needle 62 that opens and closes the second flow path 72 is accommodated in the third reservoir 84.

  In such a fuel injection valve 18, the first needle 60 is driven so as to be separated from the valve seat portion based on a control command from the electronic control device 30, whereby the fuel supplied into the first reservoir 80 is It is guided to the injection port 50 through the second storage part 82 and the first flow path 70 and is injected from the injection port 50. Further, the fuel injection angle is changed by driving the second needle 62 based on a control command from the electronic control unit 30 in accordance with the fuel injection.

  Specifically, as shown in FIG. 2A, when the second needle 62 closes the second flow path 72, the fuel flows from the side to the first flow path 70 through the second flow path 72. Is not supplied, the fuel is injected in a direction along the extending direction of the first flow path 70 indicated by a one-dot chain line L1 in FIG.

  On the other hand, as shown in FIGS. 2B and 2C, the second needle 62 is driven to be pulled out from the third storage portion 84, and the first flow path 70 is passed through the second flow path 72. When the fuel is supplied from the side, the fuel guided to the injection port 50 through the first flow path 70 is injected from the injection port 50 in a state bent to the curved portion 52 side.

  This is because the fuel introduced from the side through the second flow path 72 is pushed and bent toward the bending portion 52 through the first flow path 70, and the fuel is moved toward the bending portion 52. This is because the fuel is caused to flow along the curved portion 52 by the Coanda effect by being pushed and bent and contacting the curved portion 52.

The direction in which the fuel is injected from the fuel injection valve 18, that is, the injection angle of the fuel injected from the injection port 50 changes according to the valve opening amount of the second needle 62.
As shown in FIG. 2C, when the second needle 62 is completely opened so as not to block the second flow path 72 at all, the fuel injected from the fuel injection valve 18 is as shown in FIG. C), the fuel is injected while being largely inclined with respect to the central axis of the fuel injection valve 18 as indicated by a one-dot chain line L3.

  In FIG. 2B, the opening amount of the second needle 62 is adjusted so that the fuel injection angle is intermediate between the injection angle shown in FIG. 2A and the injection angle shown in FIG. Indicates the state. The electronic control unit 30 of the present embodiment is a fuel that is intermediate between the injection angle shown in FIG. 2 (A) and the injection angle shown in FIG. 2 (C), as indicated by a one-dot chain line L2 in FIG. 2 (B). Is set as a reference injection angle. Then, by controlling the valve opening amount of the second needle 62, the amount by which the injection angle is inclined from the reference injection angle, that is, the correction amount of the fuel injection angle is changed, and the fuel injection angle is arbitrarily changed.

  In short, as shown in FIG. 2 (A), by making the valve opening amount of the second needle 62 smaller than the valve opening amount shown in FIG. The injection angle is tilted from the reference injection angle so as to approach the stretching direction (the direction of the one-dot chain line L1 in FIG. 2A). On the other hand, as shown in FIG. 2C, the bending portion 52 is curved by increasing the valve opening amount of the second needle 62 from the valve opening amount shown in FIG. The injection angle is inclined from the reference injection angle so as to be close to.

  In the following description, as shown in FIG. 2A, the correction amount of the injection angle when the injection angle is tilted so as to approach the reference injection angle in the direction along the extending direction of the first flow path 70 is “ The correction amount α ”. FIG. 2A shows a state where the second needle 62 completely closes the second flow path 72. That is, since the state shown in FIG. 2 (A) is the state where the valve opening amount of the second needle 62 is the smallest “0”, the correction amount α is the largest in FIG. 2 (A). Thus, the state in which the valve opening amount of the second needle 62 is controlled is shown.

  In the following description, as shown in FIG. 2C, the correction amount of the injection angle when the injection angle is tilted so as to approach the reference injection angle in the direction in which the bending portion 52 is curved is referred to as “correction amount β. " FIG. 2C shows a state in which the second needle 62 does not block the second flow path 72 at all. That is, the state shown in FIG. 2C is a state in which the valve opening amount of the second needle 62 is maximized. Therefore, in FIG. The state in which the valve opening amount of the two needles 62 is controlled is shown.

  The fuel injection valve 18 installed in the combustion chamber 11 has a fuel injection angle that is increased as the correction amount β is increased so that the fuel injection angle is inclined toward the intake valve 24 as the correction amount α is increased. The direction is adjusted so as to incline toward the 12 side. That is, the correction amount α is a value indicating the amount by which the fuel injection angle is inclined toward the intake valve 24 from the reference injection angle shown in FIG. 2B, and the correction amount β is the fuel injection angle shown in FIG. This is a value indicating the amount of inclination from the reference injection angle shown in (B) to the piston 12 side.

Next, a setting mode of the correction amount of the fuel injection angle in the fuel injection control executed by the electronic control unit 30 according to the present embodiment will be described with reference to FIG.
FIG. 3 is a flowchart showing a flow of correction amount setting processing executed by the electronic control unit 30. The electronic control unit 30 executes the correction amount setting process every time the fuel injection amount and the fuel injection timing are set in the fuel injection control, and the correction amount set through the correction amount setting process when the fuel is injected. Accordingly, the fuel injection angle is controlled by driving the second needle 62.

  When this process is started, the electronic control unit 30 determines whether or not the set fuel injection timing is before the intake bottom dead center in step S120 as shown in FIG. In step S120, when it is determined that the set fuel injection timing is before the intake bottom dead center (step S120: YES), the process proceeds to step S180, and the intake stroke shown in FIG. The correction amount α corresponding to the fuel injection timing is acquired with reference to the correction amount map.

  As shown in FIG. 4 (A), a correction amount α corresponding to the fuel injection timing is set in the intake stroke correction amount map. In the intake stroke, as the intake valve 24 opens, air flows into the combustion chamber 11 from the intake port 20 through the gap between the intake valve 24 and the valve seat. Therefore, in the intake stroke, a downward airflow that flows from the upper side of the combustion chamber 11 in which the intake valve 24 is provided to the lower side of the combustion chamber 11 where the piston 12 is located is generated by the inflow of air. Since the pressure difference between the intake port 20 side and the combustion chamber 11 side is large at the beginning of the intake stroke when the intake valve 24 starts to open, and air flows into the combustion chamber 11 with the lift amount of the intake valve 24 being small, The flow velocity of the air flowing in through the gap between the intake valve 24 and the valve seat, that is, the flow velocity of the descending airflow becomes particularly fast. After that, as the intake stroke progresses to the middle stage of the intake stroke and the latter stage of the intake stroke, the flow velocity of the downdraft becomes slow. In the intake stroke correction amount map, the correction amount α is set in accordance with the change tendency of the flow velocity of the downdraft so that the influence of the downdraft can be canceled by tilting the fuel injection angle. That is, as shown in FIG. 4A, the correction amount α is maximized when the injection timing is set at the beginning of the intake stroke close to top dead center, while the injection timing is closer to bottom dead center. The correction amount α is made smaller as the fuel is injected while the intake stroke has progressed to the middle of the intake stroke and the latter of the intake stroke.

  It should be noted that the intake stroke correction amount map referred to when calculating the correction amount α only needs to be in line with the change tendency of the flow velocity of the descending air flow that has the highest flow velocity at the beginning of the intake stroke as described above. Therefore, the intake stroke correction amount map referred to in step S180 may be one in which the value of the correction amount α changes linearly with respect to the fuel injection timing, for example, as shown in FIG. . Further, as shown in FIG. 4C, the value of the correction amount α may be changed stepwise with respect to the injection timing. Further, in the correction amount map for the intake stroke shown in FIG. 4A, the correction amount α at the top dead center and the bottom dead center is substantially the same value, but the top dead center as shown in FIG. May be different from the correction amount α at the bottom dead center.

  The electronic control unit 30 reads the value of the correction amount α corresponding to the currently set fuel injection timing with reference to the intake stroke correction amount map through step S180, and sets the read value as the correction amount α. . When the correction amount α is set through step S180, the electronic control unit 30 once ends the correction amount setting process.

  On the other hand, if it is determined in step S120 that the fuel injection timing is after the intake bottom dead center (step S120: NO), the process proceeds to step S280, and correction is made with reference to the compression stroke correction amount map. Get the quantity β.

  As shown in FIG. 5 (A), a correction amount β corresponding to the fuel injection timing is set in the compression stroke correction amount map. In the compression stroke, ascending air flow that flows from the piston 12 side toward the top surface of the combustion chamber 11 to which the spark plug 16 is attached is generated in the combustion chamber 11 as the piston 12 moves up.

  The flow rate of the ascending airflow generated as the piston 12 rises in the compression stroke is proportional to the ascending speed of the piston 12, and the higher the ascending speed of the piston 12, the faster the ascending airflow velocity. The piston 12 connected to the crankshaft via the connecting rod 14 gradually increases in its speed toward the middle of the compression stroke where the crank angle is 90 ° CA, and is highest in the middle of the compression stroke. . And ascending speed becomes late gradually toward the latter half of the compression stroke. For this reason, the flow velocity of the rising air flow generated in the combustion chamber 11 also gradually increases toward the middle of the compression stroke, becomes highest in the middle of the compression stroke, and then gradually decreases toward the latter half of the compression stroke. In the compression stroke correction amount map, the correction amount β is set in accordance with the change tendency of the flow velocity of the ascending air current so that the influence of the ascending air current can be canceled by tilting the fuel injection angle. That is, as shown in FIG. 5A, the correction amount β is maximized when the injection timing is set at the middle of the compression stroke which is close to the middle between the bottom dead center and the top dead center. When fuel is injected in the latter half of the compression stroke, the correction amount β is made smaller than when fuel is injected in the middle of the compression stroke.

  It should be noted that the compression stroke correction amount map referred to when calculating the correction amount β only needs to be in line with the changing tendency of the flow velocity of the updraft where the flow velocity becomes fastest in the middle of the compression stroke as described above. Therefore, the compression stroke correction amount map referred to in step S280 may be one in which the value of the correction amount β changes linearly with respect to the fuel injection timing as shown in FIG. 5B, for example. . Further, as shown in FIG. 5C, the value of the correction amount β may change stepwise with respect to the injection timing. Further, in the compression stroke correction amount map shown in FIG. 5A, the correction amount β at the top dead center and the bottom dead center is substantially the same value, but the top dead center as shown in FIG. May be different from the correction amount β at the bottom dead center.

  The electronic control unit 30 reads the value of the correction amount β corresponding to the currently set fuel injection timing with reference to the compression stroke correction amount map through step S280, and sets the read value as the correction amount β. . When the correction amount β is set through step S280, the electronic control unit 30 once ends the correction amount setting process.

In accordance with the correction amount set through the correction amount setting process, the electronic control unit 30 drives the second needle 62 during fuel injection to adjust the fuel injection angle.
(Function)
Next, with reference to FIG. 6 and FIG. 7, an operation by adjusting the fuel injection angle in accordance with the correction amount set through the correction amount setting process will be described.

  When fuel injection is performed during the intake stroke, the fuel injection angle is equal to the correction amount α from the reference injection angle (one-dot chain line L2 in FIG. 6) as shown by the one-dot chain line arrow in FIG. It is inclined toward the intake valve 24 side. That is, the fuel is injected in a state inclined in advance toward the upstream side of the downdraft indicated by the arrow in FIG. 6 generated by the air flowing into the combustion chamber 11 through the gap between the intake valve 24 and the valve seat. Therefore, the injected fuel is deflected to the piston 12 side due to the influence of the downward airflow as shown in FIG. 6, but the fuel that has flowed to the piston 12 side due to the influence of the downward airflow enters the target region Z1. To reach.

  On the other hand, when the fuel injection is performed during the compression stroke, the fuel injection angle is changed from the reference injection angle (the one-dot chain line L2 in FIG. 7) to the correction amount β as shown by the one-dot chain arrow in FIG. It is tilted toward the piston 12 by the amount. That is, the fuel is injected in a state tilted in advance toward the upstream side of the ascending air current shown by the arrow in FIG. Therefore, as shown in FIG. 7, the injected fuel is affected by the updraft and is changed toward the upper side of the combustion chamber 11 in which the intake valve 24 and the exhaust valve 26 are provided. As a result, the fuel that has flowed through reaches the target region Z2.

According to the embodiment described above, the following effects can be obtained.
(1) When fuel is injected during the intake stroke, the fuel is injected in a state of being tilted in advance toward the upstream side of the downdraft, so that the injected fuel is affected by the downflow and the piston 12 Even if the fuel is deflected to the side, the injected fuel can be prevented from excessively approaching the top surface of the piston 12.

  Further, as the flow rate of air flowing into the combustion chamber 11 through the gap between the intake valve 24 and the valve seat is faster and the injected fuel is more likely to flow to the piston 12 side by the downdraft, the fuel injection angle becomes the intake valve 24. Tilted to the side. Therefore, the injection angle can be changed in accordance with the magnitude of the influence of the downdraft on the injected fuel, and the influence of the downflow on the injected fuel can be suitably suppressed.

  In short, it is possible to suppress the occurrence of smoke by suppressing the influence of the downdraft generated in the combustion chamber 11 on the injected fuel and reducing the adhesion of fuel to the top surface of the piston 12.

  (2) This is the amount by which the fuel injection angle is inclined toward the intake valve 24 when the fuel is injected at the beginning of the intake stroke where the flow velocity of the air flowing into the combustion chamber 11 becomes particularly fast from the gap between the intake valve 24 and the valve seat. Since the correction amount α is maximized, the injection angle can be set in accordance with the magnitude of the influence of the downdraft.

  (3) When the fuel is injected during the compression stroke, the fuel is injected in a state inclined in advance toward the upstream side of the updraft, so that the injected fuel is affected by the updraft and the piston 12 Even if the fuel is deflected so as to move away from the fuel, it is possible to prevent the injected fuel from excessively approaching the wall surface of the cylinder 10.

  Further, the upward flow rate of the ascending air flow generated in the combustion chamber 11 as the piston 12 rises is faster, and the fuel injection angle becomes larger as the injected fuel tends to flow toward the top surface of the combustion chamber 11 by the ascending air flow. It is tilted toward the piston 12 side. Therefore, the injection angle can be changed in accordance with the magnitude of the influence of the updraft on the injected fuel, and the influence of the updraft on the injected fuel can be suitably suppressed.

In short, oil dilution can be suppressed by suppressing the influence of the rising airflow generated in the combustion chamber 11 on the injected fuel and reducing the adhesion of fuel to the wall surface of the cylinder 10.
(4) When the fuel is injected in the middle of the compression stroke in which the rising speed of the piston 12 is fast and the flow velocity of the rising air flow generated in the combustion chamber 11 is particularly fast as the piston 12 is raised, the fuel injection angle is set to the piston 12. Since the correction amount β, which is the amount tilted to the side, is maximized, the injection angle can be set in accordance with the magnitude of the effect of the rising airflow.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
-The smaller the injection amount of the fuel injected into the combustion chamber 11, the lower the ratio of the amount of fuel to the amount of air present in the combustion chamber 11. Further, the smaller the injection amount of the fuel injected into the combustion chamber 11, the lower the penetration force of the injected fuel. On the other hand, when the amount of fuel injected from the fuel injection valve 18 is large, the ratio of the amount of fuel to the amount of air present in the combustion chamber 11 is high, and the penetration force of the injected fuel is high. Therefore, the injected fuel is hardly affected by the air flow in the combustion chamber 11.

  Therefore, when the fuel injection amount is large, it may not be necessary to execute correction of the injection angle. FIG. 8 shows the flow of the correction amount setting process according to the first modification example in which the fuel is injected at the reference injection angle without setting the fuel injection angle correction amount when the fuel injection amount is large. It is a flowchart to show.

  In the correction amount setting process according to the first modification, a process for determining whether or not the fuel injection amount is equal to or greater than a specified value is added to the correction amount setting process described in the above embodiment. ing.

  Specifically, as shown in FIG. 8, when it is determined in step S120 that the set fuel injection timing is before the intake bottom dead center (step S120: YES), the process proceeds to step S130. Then, it is determined whether or not the set fuel injection amount is less than the specified value X. Note that the specified value X is an injection amount that provides a penetration force that allows the fuel injected during the intake stroke to reach the target region Z1 without correcting the fuel injection angle. Find it by calculation.

  In step S130, when it is determined that the set fuel injection amount is less than the prescribed value X (step S130: YES), the process proceeds to step S180, and FIG. The correction amount α corresponding to the fuel injection timing is acquired with reference to the intake stroke correction amount map shown in A).

  On the other hand, if it is determined in step S130 that the set fuel injection amount is equal to or greater than the specified value X (step S130: NO), step S180 is skipped and the correction amount α is not set. The correction amount setting process is terminated, and the fuel is injected at the reference injection angle without correcting the fuel injection angle.

  As shown in FIG. 8, when it is determined in step S120 that the set fuel injection timing is after the intake bottom dead center (step S120: NO), the process proceeds to step S230 and is set. It is determined whether or not the fuel injection amount being less than the specified value Y. The specified value Y is an injection amount that provides a penetration force that allows the fuel injected during the compression stroke to reach the target region Z2 without correcting the fuel injection angle. Find it by calculation.

  If it is determined in step S230 that the set fuel injection amount is less than the prescribed value Y (step S230: YES), the process proceeds to step S280, and FIG. A correction amount β corresponding to the fuel injection timing is acquired with reference to the compression stroke correction amount map shown in A).

  On the other hand, if it is determined in step S230 that the set fuel injection amount is equal to or greater than the specified value Y (step S230: NO), step S280 is skipped and the correction amount β is not set. The correction amount setting process is terminated, and the fuel is injected at the reference injection angle without correcting the fuel injection angle.

  When the correction amount setting process according to the first modification example is executed, when the fuel injection amount is equal to or greater than the specified amount, the fuel is injected without being inclined. For this reason, when the fuel injection amount is large and the injected fuel is not easily affected by the air flow in the combustion chamber 11, the injection angle is not inclined toward the piston 12 side or the intake valve 24 side, and the reference injection is performed. Fuel is injected at an angle. Therefore, it is possible to prevent the fuel injection angle from being tilted unnecessarily.

  -The higher the engine speed, the higher the flow rate of air flowing into the combustion chamber 11 through the gap between the intake valve 24 and the valve seat in the intake stroke. Therefore, the higher the engine rotation speed, the higher the flow velocity of the downdraft generated in the combustion chamber 11 during the intake stroke. Further, the higher the engine rotation speed, the higher the ascending speed of the piston 12 in the compression stroke. Therefore, the higher the engine speed, the higher the flow rate of the updraft generated in the combustion chamber 11 during the compression stroke. Therefore, the correction amount α and the correction amount β may be increased or decreased according to the engine rotation speed when fuel is injected.

  Further, the lower the injection pressure of the fuel injected into the combustion chamber 11, the lower the penetration force of the injected fuel, and the injected fuel becomes more susceptible to the air flow in the combustion chamber 11. Therefore, the correction amount α and the correction amount β may be increased or decreased according to the fuel injection pressure.

  FIG. 9 shows a second modification example in which a process for increasing / decreasing the correction quantity α and the correction quantity β according to the engine speed and the fuel injection pressure is added to the correction quantity setting process shown as the first modification example. It is a flowchart which shows the flow of a correction amount setting process.

  In the correction amount setting process according to the second modification example, when it is determined in step S130 that the set fuel injection amount is less than the specified value X as shown in FIG. 9 ( In step S130: YES), the process proceeds to step S140, and an intake stroke correction amount map corresponding to the engine speed and the fuel injection pressure is acquired. Here, an intake stroke corresponding to the engine rotational speed and the fuel injection pressure at the currently set fuel injection timing from among a plurality of intake stroke correction amount maps prepared according to the combination of the engine rotational speed and the fuel injection pressure. A correction amount map is obtained.

  As shown in FIG. 10 (A), the higher the engine speed, the larger the increase in the flow velocity of the ascending and descending airflow generated in the combustion chamber 11, that is, the increase in the in-cylinder airflow velocity. Therefore, in accordance with the changing tendency of the increase amount of the in-cylinder airflow velocity, as shown in FIG. 10B, the correction amount map for the intake stroke is set such that the increase amount of the correction amount α increases as the engine rotational speed increases. Is to be selected.

  Further, the higher the fuel injection pressure, the higher the penetration force of the injected fuel, and the less the influence of the updraft and the downdraft generated in the combustion chamber 11. Accordingly, the intake stroke correction amount map is selected so that the correction amount α decreases as the fuel injection pressure increases in accordance with such a tendency.

  Since the fuel injection pressure changes according to the discharge amount of the fuel pump that changes according to the engine speed and the temperature of the fuel, the fuel injection pressure is estimated based on the engine speed and the engine coolant temperature, and the intake stroke A correction amount map can also be selected. That is, the fuel injection pressure becomes higher as the engine speed is higher and the discharge amount of the fuel pump is larger, and as the engine cooling water temperature is higher and the fuel temperature is higher. Therefore, a plurality of regions (P1, P2, P3, P4 in FIG. 11) corresponding to the height of the fuel injection pressure are set as shown in FIG. 11 (A), and the fuel as shown in FIG. 11 (B). It is also possible to acquire an intake stroke correction amount map in which the correction amount α decreases as it belongs to a region indicating that the injection pressure is high.

  When the intake stroke correction amount map corresponding to the engine speed and the fuel injection pressure is acquired in step S140, the process proceeds to step S180, and the correction amount corresponding to the injection timing is referred to with reference to the acquired intake stroke correction amount map. Acquire α.

  If it is determined in step S230 that the set fuel injection amount is less than the specified value Y (step S230: YES), the process proceeds to step S240, and the engine is the same as in step S140 described above. A compression stroke correction amount map corresponding to the rotation speed and the fuel injection pressure is acquired. Again, a plurality of compression stroke correction amount maps are prepared in accordance with the combination of the engine speed and the fuel injection pressure, and the currently set fuel injection is selected from the prepared plurality of compression stroke correction amount maps. A compression stroke correction amount map corresponding to the engine speed and fuel injection pressure at the time is acquired.

  Also in this case, the correction amount map for the intake stroke is selected so that the increase amount of the correction amount β increases as the engine speed increases, and the correction amount β increases as the fuel injection pressure increases. The correction amount map for the compression stroke is selected so as to be small.

  When the compression stroke correction amount map corresponding to the engine rotational speed and the fuel injection pressure is acquired through step S240, the process proceeds to step S280, and the correction amount corresponding to the injection timing is referred to with reference to the acquired compression stroke correction amount map. Get β.

  According to the correction amount setting process according to the second modified example, the amount by which the fuel injection angle is tilted increases as the engine speed increases. Therefore, even when the engine rotation speed is high and the flow rate of the updraft or downdraft generated in the combustion chamber 11 is high, the effect of the updraft or downdraft is increased by increasing the amount of tilting the injection angle accordingly. Can be suppressed.

In other words, the fuel injection angle can be set so as to cancel out the change in the magnitude of the influence by taking into account the change in the magnitude of the influence of the air flow due to the change in the engine rotation speed.
Further, the amount by which the fuel injection angle is tilted increases as the fuel injection pressure is low, while the amount by which the fuel injection angle is tilted decreases as the fuel injection pressure increases. Therefore, the fuel injection angle can be set so as to cancel out the change in the magnitude of the influence by taking into account the change in the magnitude of the influence of the air flow due to the change in the fuel injection pressure.

  The process for increasing / decreasing the correction amount α and the correction amount β according to the engine rotational speed and the fuel injection pressure as described above is not limited to the correction amount setting process according to the first modification example, but refers to FIG. It can also be combined with the correction amount setting process described above. Specifically, the process of step S140 is added between step S120 and step S180 in the correction amount setting process of FIG. 3, and the process of step S240 is added between step S120 and step S280. As a result, regardless of whether the fuel injection amount is equal to or greater than the prescribed values X and Y, the correction amounts α and β are set, and the correction amount α and the correction amount β are increased or decreased according to the engine speed and the fuel injection pressure. The correction amount setting process to be performed can be realized.

  A plurality of specific methods for increasing / decreasing the correction amount α and the correction amount β according to the engine speed and the fuel injection pressure are prepared as in the correction amount setting process according to the second modification. The correction amount map is not limited to the method for selecting the correction amount map from the correction amount map, and can be changed as appropriate.

  For example, the correction amount can be increased or decreased by multiplying the correction amount α or the correction amount β calculated from one basic correction amount map by a correction coefficient set according to the engine speed or the fuel injection pressure.

  Further, a configuration in which only one of the correction amount α and the correction amount β is increased or decreased according to the engine rotational speed and the fuel injection pressure, or the correction amount α according to only one of the engine rotational speed and the fuel injection pressure, A configuration in which the correction amount β is increased or decreased can also be employed.

  In the above embodiment, the fuel injection valve 18 that changes the fuel injection angle by controlling the second needle 62 is illustrated, but the present invention is a fuel that can change the fuel injection angle. Any cylinder injection type internal combustion engine provided with an injection valve can be applied. Therefore, the configuration of the fuel injection valve is not limited to the configuration of the fuel injection valve 18 illustrated in the above embodiment. That is, the fuel injection valve only needs to be capable of changing the fuel injection angle.

  In the above embodiment, the configuration in which the fuel injection angle is tilted both in the case of injecting fuel in the intake stroke and in the case of injecting fuel in the compression stroke is shown. However, the injection angle is only applied when fuel is injected in the compression stroke. You may make it perform the process which inclines. Further, the process of inclining the injection angle may be executed only when fuel is injected in the intake stroke. Therefore, the present invention is applied not only to an internal combustion engine that switches between intake stroke injection and compression stroke injection, but also to an internal combustion engine that performs only intake stroke injection, and the fuel injection angle is set according to the flow velocity of the downdraft. You can also tilt it.

  In the above embodiment, when the fuel injection valve 18 is provided on the wall surface of the cylinder 10 located below the intake valve 24 provided on the upper surface of the combustion chamber 11 and fuel is injected during the intake stroke, the same fuel is used. The configuration in which the fuel injection angle is inclined toward the intake valve 24 provided above the injection valve 18 is illustrated. On the other hand, the present invention can also be applied to a direct injection internal combustion engine in which a fuel injection valve is provided on the upper surface of the combustion chamber, similarly to the intake valve. Even in this case, since air flows into the combustion chamber through the gap between the intake valve and the valve seat during the intake stroke, the fuel injected from the fuel injection valve is affected by this air flow. On the other hand, when the present invention is applied to a cylinder injection internal combustion engine in which a fuel injection valve is provided on the upper surface of such a combustion chamber, the intake valve side that is upstream of the flow of air flowing into the combustion chamber is provided. Since the fuel is injected toward the front, it is possible to prevent the injected fuel from flowing by the air flow and adhering to the cylinder wall surface or the piston top surface.

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 10 ... Cylinder, 11 ... Combustion chamber, 12 ... Piston, 14 ... Connecting rod, 16 ... Spark plug, 18 ... Fuel injection valve, 20 ... Intake port, 22 ... Exhaust port, 24 ... Intake valve, 26 ... Exhaust valve, 30 ... Electronic control device, 31 ... Crank position sensor, 32 ... Cam position sensor, 33 ... Accelerator position sensor, 34 ... Vehicle speed sensor, 35 ... Water temperature sensor, 36 ... Fuel pressure sensor, 50 ... Injection port, 52 ... Curved part 60 ... 1st needle 62 ... 2nd needle 70 ... 1st flow path 72 ... 2nd flow path 80 ... 1st storage part 82 ... 2nd storage part 84 ... 3rd storage part

Claims (8)

A fuel injection control device for a direct injection internal combustion engine that changes a fuel injection angle to be injected into a combustion chamber by controlling a fuel injection valve capable of changing a fuel injection angle,
When fuel is injected during the intake stroke, the fuel injection angle is increased as the fuel is injected when the flow rate of air flowing into the combustion chamber from the gap between the opened intake valve and the valve seat is high. A fuel injection control device that is tilted toward the intake valve. The fuel injection control device according to claim 1,
When fuel is injected at the beginning of the intake stroke when the intake valve starts to open, the amount of fuel injection angle is increased most to the intake valve side, and the fuel is injected as the fuel is injected later in the intake stroke. A fuel injection control device characterized in that an amount of tilting the angle toward the intake valve is reduced. A fuel injection control device for a direct injection internal combustion engine that changes a fuel injection angle to be injected into a combustion chamber by controlling a fuel injection valve capable of changing a fuel injection angle,
When fuel is injected during the compression stroke, the fuel injection angle is tilted toward the piston as the fuel is injected when the flow rate of the ascending air flow generated in the combustion chamber is fast as the piston rises. A fuel injection control device. The fuel injection control device according to claim 3, wherein
When fuel is injected during a compression stroke, the fuel injection angle is tilted toward the piston as the fuel is injected when the ascending speed of the piston is high. The fuel injection control device according to claim 3, wherein
When fuel is injected in the middle of the compression stroke, the amount by which the injection angle is inclined to the piston side is maximized, and when fuel is injected in the early and late stages of the compression stroke, the fuel is injected in the middle of the compression stroke. The fuel injection control device is characterized in that the amount by which the injection angle is inclined toward the piston side is reduced. In the fuel injection control device according to claim 2 or 5,
A fuel injection control device characterized in that the amount of inclination of the fuel injection angle is increased as the engine rotational speed when fuel is injected is higher. In the fuel-injection control apparatus as described in any one of Claims 1-6,
The lower the injection pressure of the fuel injected from the fuel injection valve into the combustion chamber, the greater the amount of inclination of the fuel injection angle, while the higher the injection pressure of fuel injected from the fuel injection valve into the combustion chamber. A fuel injection control device characterized in that the amount by which the fuel injection angle is inclined is reduced as occasion demands. In the fuel-injection control apparatus as described in any one of Claims 1-7,
The fuel injection control device, wherein when the fuel injection amount injected by the fuel injection valve is equal to or greater than a specified value, the fuel is injected without tilting the fuel injection angle.

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