JP3695039B2 - In-cylinder direct injection spark ignition engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of an intake system in an in-cylinder direct injection spark ignition engine.
[0002]
[Prior art]
In-cylinder direct-injection spark-ignition engine with an injector (fuel injection valve) facing the cylinder to inject fuel directly into the cylinder in order to achieve stratification of the air-fuel mixture that collects fuel near the spark plug There is.
[0003]
As a conventional in-cylinder direct injection type spark ignition engine, for example, there is one shown in FIG. 10 (see Japanese Patent Laid-Open No. 6-81651).
[0004]
This will be described. The injector 6 faces the cylinder 14 from the side of the combustion chamber ceiling wall 20 and injects fuel toward the cavity 31 recessed in the crown 30 of the piston 1.
[0005]
An intake port 21 is formed upright along the cylinder 14. The intake air flowing into the cylinder 14 from the upright intake port 21 descends along the cylinder 14 as shown by the arrow in the drawing, and then a reverse tumble R that turns along the piston crown 30 is generated. The fuel spray swirling with the reverse tumble R on the cavity 31 rises toward the spark plug 4 along the cavity 31. Thereby, the rich air-fuel mixture is collected in the vicinity of the spark plug 4.
[0006]
[Problems to be solved by the invention]
However, in such a conventional in-cylinder direct injection spark ignition engine, since the upright intake port 21 is provided so as to penetrate the upper part of the cylinder head 9, the intake manifold is provided at the upper part of the cylinder head 9. There is a problem that the overall height of the engine becomes large because it is necessary to connect.
[0007]
In addition, since the reverse tumble R is always generated in the cylinder 14 regardless of the operating conditions, the fuel and air are not sufficiently mixed in the operating state in which the fuel is injected from the injector 6 during the compression stroke, and the cylinder 14 The problem is that it is difficult to make a homogeneous mixture.
[0008]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an intake system and a combustion chamber structure suitable for an in-cylinder direct injection spark ignition engine.
[0009]
[Means for Solving the Problems]
An in-cylinder direct injection spark ignition engine according to claim 1 includes an intake port for introducing intake air into the cylinder, an intake valve for opening and closing the intake port in synchronization with engine rotation, and an injector for injecting fuel into the cylinder And an in-cylinder direct injection spark ignition engine having a spark plug for igniting an air-fuel mixture in the cylinder, the intake port has a port shape that causes forward tumble in the intake air flow, and is engaged with the stem portion of the intake valve And a tumble control valve that shields the combustion chamber center side of the intake port according to operating conditions and causes reverse tumble in the intake air flow.
[0011]
Cylinder direct injection spark ignition engine according to claim 2 is the invention according to claim 1, the center line of the tumble control valve is substantially orthogonal to the passage center line of the intake port in plan view, the valve body While forming the outer peripheral surface which protrudes from the wall surface of an intake port, the recessed part which curves along the wall surface of an intake port was formed in the valve body.
[0012]
The direct injection type spark ignition engine according to claim 3 includes an intake port that introduces intake air into the cylinder, an intake valve that opens and closes the intake port in synchronization with engine rotation, and an injector that injects fuel into the cylinder. And a spark injection engine that ignites the air-fuel mixture in the cylinder, and the intake port has a port shape that causes forward tumble in the intake air flow, and is a valve interposed in the intake port The body is rotatably supported via a shaft provided on the same axis as the stem portion of the intake valve, and rotates according to operating conditions to shield the combustion chamber center side of the intake port and reverse tumble the intake flow. It was shall comprise a tumble control valve that occurs.
[0013]
The in-cylinder direct injection spark ignition engine according to claim 4 is the invention according to any one of claims 1 to 3 , wherein the intake valve is an umbrella seated at an opening of an intake port with respect to a ceiling wall of the combustion chamber. And the tumble control valve is disposed in the intake port directly above the umbrella portion of the intake valve .
[0014]
The direct injection type spark ignition engine according to claim 5 is the invention according to any one of claims 1 to 4 , wherein the fuel injection timing of the injector is set to an intake stroke at a high load, and the injector The fuel injection timing is set to the compression stroke at low load.
[0015]
Operation and effect of the invention
2. A direct in-cylinder spark ignition engine according to claim 1, wherein, for example, in a stratified charge combustion region operated at a lean air-fuel ratio, under a driving condition in which fuel is injected from an injector in a compression stroke in which a piston is raised, The valve is held in a position that shields the combustion chamber center side of the intake port. As a result, the intake flow flowing into the cylinder through the intake port causes a reverse tumble that descends along the cylinder wall located directly below the intake port and then proceeds to the piston crown. As a result, the fuel injected from the injector to the combustion chamber in the compression stroke swirls together with the reverse tumble, and as the piston approaches top dead center, the mixture is stratified to collect the rich mixture near the spark plug. At the same time, the flame flow is promoted by the gas flow of the reverse tumble. As a result, the lean limit value of the air-fuel ratio at which combustibility is ensured is expanded, and fuel consumption is reduced. Further, it is not necessary to increase the fuel injection amount in the cold state, and the emission can be improved.
[0016]
For example, in a homogeneous combustion zone operated at a stoichiometric air-fuel ratio, in the operating condition in which fuel is injected from the injector into the cylinder during the intake stroke when the piston descends, the position where the tumble control valve does not shield the combustion chamber center side of the intake port Retained. The intake flow that flows into the cylinder through the intake port causes a forward tumble that descends along the cylinder wall facing the intake port and then travels to the piston crown. As a result, the fuel spray injected in the intake stroke is promoted to be mixed with the air by the forward tumble generated in the cylinder, and the mixture is homogenized, and the propagation of the flame is promoted by the gas flow of the forward tumble. It is. As a result, the rich limit value of the air-fuel ratio at which combustibility is ensured is expanded, and the output performance is improved.
[0017]
In addition, because the intake port is provided with a structure that is greatly inclined with respect to the center line of the cylinder, the height of the engine is reduced compared to a conventional device having an upright intake port that penetrates the top of the cylinder head. Can do.
[0019]
3. The direct in-cylinder injection spark ignition engine according to claim 2 , wherein the tumble control valve is held at a position where the outer peripheral surface of the valve body protrudes from the wall surface of the intake port, so that the passage center line of the intake port is disposed in the cylinder. Is bent along the center line, and the intake flow is bent along the cylinder wall located directly under the intake port, thereby effectively generating the reverse tumble. As a result, the limit value of the lean air-fuel ratio at which combustibility is ensured is expanded, and fuel consumption is reduced.
[0020]
The tumble control valve is held at a position where the concave portion of the valve body is continuous with the wall surface of the intake port, so that the port area is increased and the intake charge efficiency of the engine can be increased.
[0021]
4. The direct in-cylinder spark ignition engine according to claim 3 , wherein, for example, in a stratified combustion region, the valve body of the tumble control valve is held at a position where the combustion chamber center side of the intake port is shielded to reverse tumble the intake flow. Occur. On the other hand, in the homogeneous combustion zone, the valve body of the tumble control valve is rotated around the intake valve to drive to a position where the combustion chamber center side of the intake port is not shielded, thereby causing forward tumble in the intake flow.
[0022]
5. The direct in-cylinder spark ignition engine according to claim 4 , wherein a tumble control valve disposed immediately above the umbrella portion of the intake valve shields the combustion chamber center side of the intake port through the intake port. The intake flow flowing into the cylinder is bent along the cylinder wall located directly under the intake port, thereby effectively generating a reverse tumble. As a result, the limit value of the lean air-fuel ratio at which combustibility is ensured is expanded, and fuel consumption is reduced.
[0024]
In the direct in-cylinder injection spark ignition engine according to claim 5 , fuel is injected from the injector during a compression stroke in which the piston rises at low load. The fuel spray merges with the reverse tumble and the rich mixture is collected in the vicinity of the spark plug. As a result, the lean limit value of the air-fuel ratio at which combustibility is ensured is expanded, and fuel consumption is reduced.
[0025]
When the load is high, fuel is injected from the injector during the intake stroke in which the piston descends. The fuel spray is promoted to be mixed with air by the forward tumble generated in the cylinder, and when the ignition timing is reached, a homogeneous air-fuel mixture is formed in the combustion chamber. As a result, the rich limit value of the air-fuel ratio at which combustibility is ensured is expanded, and the output is improved.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0027]
As shown in FIG. 1, two intake ports 21 and two exhaust ports 23 are opened to face each other in the combustion chamber ceiling wall 20 inclined in a pent roof shape. The combustion chamber ceiling wall 20 is configured by an intake port side inclined surface 25 where each intake port 21 opens and an exhaust port side inclined surface 26 where each exhaust port 23 opens.
[0028]
A spark plug 4 that faces the inside of the cylinder 14 from the center of the combustion chamber ceiling wall 20 is provided. Two intake valves 7 and two exhaust valves 8 are provided on the combustion chamber ceiling wall 20 so as to face each other with the spark plug 4 interposed therebetween.
[0029]
An injector 6 facing the inside of the cylinder 14 from the side of the combustion chamber ceiling wall 20 is provided. The fuel discharged from a fuel pump (not shown) is guided to the injector 6 after being regulated through a pressure regulator. As the injector 6 opens, fuel is injected into the cylinder 14 from the injection port.
[0030]
The injector 6 has its valve opening timing and valve opening period (injection pulse width) controlled by the control unit according to the operating state.
[0031]
The control unit calculates the basic injection amount Tp by the following equation based on the intake air amount Qa detected by each sensor (not shown) and the engine speed N.
[0032]
Tp = K · Qa / N (1)
However, K is a constant, and the final fuel injection amount Ti is set so that the air-fuel ratio falls within a narrow range centered on stoichiometry in a predetermined homogeneous combustion region, or the air-fuel ratio for realizing stratified combustion becomes the air-fuel ratio. The fuel injection amount is feedback-controlled by calculation using an equation.
[0033]
Ti = Tp × α × COEF + Ts (2)
Where α is the air-fuel ratio feedback correction coefficient, COEF is the sum of various correction coefficients using parameters such as the cooling water temperature correction coefficient and the correction coefficient for stratified combustion, and Ts is the invalid injection pulse width.
[0034]
A pulse signal corresponding to the calculated fuel injection amount Ti is output to the injector 6 to perform fuel injection control.
[0035]
The control unit adjusts the air-fuel ratio of the air-fuel mixture supplied to the cylinder 1 to a leaner side than the stoichiometry in a stratified combustion region where the engine load and the rotational speed are not more than predetermined values. The air-fuel ratio of the air-fuel mixture supplied to the cylinder 1 is adjusted to the stoichiometric or rich side in a homogeneous combustion region where the engine load or engine speed exceeds a predetermined value.
[0036]
The fuel injected into the cylinder 14 as the injector 6 is opened is mixed with the air sucked from the intake port 21 as each intake valve 7 is opened. The air-fuel mixture formed in the cylinder 14 ignites and burns through the spark plug 4 while being compressed by the piston 1. The burned gas lowers the piston 1 and extracts the rotational force via the crankshaft, and is then discharged from each exhaust port 23 as the exhaust valve 8 is opened during the exhaust stroke in which the piston 1 moves up. Each of these processes is repeated continuously.
[0037]
The fuel injection timing, which is the valve opening timing of the injector 6, is set in the latter half of the compression stroke in which the piston 1 rises in the stratified combustion region where the engine load and rotation speed are equal to or less than a predetermined value based on a preset map. Is set to an intake stroke in which the piston 1 descends in a homogeneous combustion region in which the load or the rotational speed of the engine rises above a predetermined value.
[0038]
The injector 6 faces the inside of the cylinder 14 from the side of the umbrella portion 7a of each intake valve 7 and from between each umbrella portion 7a. The injector 6 is attached to be inclined with respect to the center line of the cylinder 14 so that the nozzle hole thereof faces the crown portion 30 of the piston 1. The fuel spray injected from the injection port of the injector 6 diffuses radially such that its center line is inclined downward at a predetermined angle with respect to the horizontal line.
[0039]
Each intake port 21 is greatly inclined with respect to the center line of the cylinder 14 such that the passage center line faces the exhaust port side inclined surface 26 and the cylinder 14. As a result, the intake air flowing into the cylinder 14 from each intake port 21 is lowered along the exhaust port side inclined surface 26 and the cylinder 14 as shown by white arrows in FIG. Produces a forward tumble T that rises along.
[0040]
The intake port 21 is provided with a tumble control valve 40 that shields the center side of the combustion chamber and causes reverse tumble in the intake air flow. The tumble control valve 40 protrudes from the wall surface of the intake port 21 at a position shown in FIG. 1, and the passage center line of the intake port 21 is greatly curved downward in the front view of FIG. As a result, the intake air flowing into the cylinder 14 through the intake port 21 is lowered along the cylinder 14 located directly below the intake port 21 as shown by the white arrow in FIG. A reverse tumble R that rises along 30 occurs.
[0041]
A cavity 31 that is recessed in a concave shape is formed in the crown portion 30 of the piston 1. The cavity 31 is disposed below the intake port side inclined surface 25 from the center of the piston crown 30.
[0042]
The injector 6 is attached so that its nozzle hole is directed toward the cavity 31, and the fuel spray injected from the nozzle hole spreads radially toward the cavity 31.
[0043]
In the cavity 31, a slope 32 that is inclined toward the spark plug 4 is formed. When the fuel spray injected from the injector 6 swirls together with the reverse tumble R generated in the cylinder 14, the fuel spray rises along the slope 32, and the rich air-fuel mixture is collected in the vicinity of the spark plug 4.
[0044]
The convex portion 34 of the piston crown portion 30 is formed so as to be inclined along the pent roof-like combustion chamber ceiling wall 20.
[0045]
The outer peripheral portion 33 of the piston crown portion 30 is formed in a planar shape facing the outer peripheral portion of the combustion chamber ceiling wall 20 in parallel. As a result, when the piston 1 reaches the vicinity of the top dead center, a squish toward the center of the combustion chamber 3 is generated in the air compressed between the piston crown 30 and the combustion chamber ceiling wall 20.
[0046]
As shown in FIG. 3, the tumble control valve 40 that adjusts the flow direction of the intake air introduced from the intake port 21 into the combustion chamber 3 includes a cylindrical valve body 41 interposed in each intake port 21. A valve body 41 interposed in the intake port 21 of each cylinder is rotatably supported via a shaft 45 common to the cylinder head 9.
[0047]
The shaft 45 is provided in parallel with a crankshaft (not shown). Thereby, the center line of the tumble control valve 40 is substantially orthogonal to the passage center line of the intake port 21 on the plan view. The shaft 45 is offset from the outside of the intake port 21 so that the passage area of the intake port 21 is not reduced.
[0048]
Each valve body 41 is disposed immediately above the umbrella portion 7 a of each intake valve 7. The cylinder head 9 is formed with a recess 27 that faces the intake port 21 and accommodates the tumble control valve 40 so as to be rotatable.
[0049]
As shown in FIG. 1, the tumble control valve 40 has an outer peripheral surface 44 that protrudes in a cylindrical shape from the wall surface of the intake port 21 at a position where reverse tumble occurs. The outer peripheral surface 44 protrudes from the wall surface on the combustion chamber center side of the intake port 3 located above the umbrella portion 7 a of the intake valve 7 and curves the passage center line of the intake port 3 along the center line of the cylinder 14.
[0050]
A groove 42 that engages with the stem portion 7 b of the intake valve 7 is formed on the outer peripheral surface 44. When the tumble control valve 40 rotates about the shaft 45, the outer peripheral surface 44 does not collide with the stem portion 7 b of the intake valve 7.
[0051]
As shown in FIG. 2, the tumble control valve 40 has a concave portion 43 that continuously curves on the wall surface of the intake port 21 at a position that does not protrude into the intake port 21. The recess 43 continues to the wall surface of the intake port 21 without a step, and introduces the intake air linearly from the intake port 21 to the combustion chamber 3.
[0052]
The shaft 45 is rotationally driven via an actuator 46. A control unit 49 for controlling the operation of the actuator 46 drives the engine load and the rotational speed where the engine speed is a predetermined value or less to a position where the tumble control valve 40 protrudes from the intake port 21 to reverse tumble the intake flow. To occur. On the other hand, the tumble control valve 40 is driven to a position where it does not protrude from the intake port 21 in a homogeneous combustion region where the engine load or the rotational speed rises above a predetermined value, thereby causing forward tumble in the intake flow.
[0053]
In FIG. 3, reference numeral 15 denotes an intake manifold that guides intake air by being connected to each intake port 21, and 16 denotes a throttle chamber that houses a throttle valve 17.
[0054]
It is comprised as mentioned above, Next, an effect | action is demonstrated.
[0055]
In the stratified combustion zone, as shown in FIG. 4, the tumble control valve 40 is held at a position where it protrudes to the intake port 21. As a result, the intake air flowing into the cylinder 14 through the intake port 21 as each intake valve 7 is opened is moved along the cylinder 14 as shown by the white arrow in FIG. After being lowered, a reverse tumble R that rises along the piston crown 30 is generated.
[0056]
Thus, the reverse tumble R is generated in the cylinder 14, so that the fuel injected from the injector 6 into the cylinder 14 in the second half of the compression stroke swirls with the reverse tumble on the cavity 31 and swirls along the cavity 31. Then, it is heated by the piston 1, and its atomization and vaporization proceed, and rises along the slope 32 to the center of the combustion chamber 3. As a result, as shown in FIG. 4 (b), as the piston 1 approaches the top dead center, the air-fuel mixture that collects the rich air-fuel mixture in the vicinity of the spark plug 4 is stratified, and the reverse tumble R The gas flow promotes the propagation of flame. As a result, the limit value of the lean air-fuel ratio at which combustibility is ensured is expanded, and fuel consumption is reduced. Further, it is not necessary to increase the fuel injection amount in the cold state, and the emission can be improved.
[0057]
Further, since the fuel injected from the injector 6 into the cylinder 14 is temporarily lowered by the reverse tumble R, it is possible to prevent liquid fuel from directly adhering to the spark plug 4 and to prevent misfire.
[0058]
On the other hand, in the homogeneous combustion region, as shown in FIG. 5, the concave portion 43 of the tumble control valve 40 is held at a position continuous with the wall surface of the intake port 21. As a result, as the intake valves 7 are opened, the intake air that flows into the cylinder 14 through the intake port 21, as indicated by the white arrows in FIG. Then, after descending along the cylinder 14, a forward tumble T that rises along the piston crown 30 occurs.
[0059]
The forward tumble T is generated by the intake flow that flows linearly from the intake port 21 to the cylinder 14, while the reverse tumble R is generated by the intake flow that flows meandering from the intake port 21 to the cylinder 14. The power of tumble T is stronger than reverse tumble R.
[0060]
As a result of the strong forward tumble T occurring in the cylinder 14, the fuel spray injected from the injector 6 into the combustion chamber 3 during the intake stroke swirls with the forward tumble T in the cylinder 14 to promote mixing with air. A homogeneous air-fuel mixture is formed in the combustion chamber 3 until the piston 1 rises and the ignition timing is reached. In the homogeneous combustion region, the air-fuel ratio of the air-fuel mixture supplied to the combustion chamber 3 is adjusted to the stoichiometric or rich side, so that the homogeneous air-fuel mixture is reliably ignited and the propagation of flame is promoted, The output performance can be improved.
[0061]
In the homogeneous combustion region, the concave portion 43 of the tumble control valve 40 is continuous with the wall surface of the intake port 21, so that the port area is expanded and the intake charge efficiency of the engine can be increased.
[0062]
Since each intake port 21 is provided with a large inclination with respect to the center line of the cylinder 14, the mounting position of the intake manifold 15 can be prevented from being increased, and the engine can be made compact.
[0063]
Next, the embodiment shown in FIGS. 6 and 7 will be described. The parts corresponding to those in FIGS. 1 and 3 are denoted by the same reference numerals.
[0064]
In the present embodiment, the tumble control valve 50 that adjusts the flow direction of intake air introduced from the intake port 21 into the combustion chamber 3 includes a valve body 51 interposed in the intake port 21. The valve body 51 interposed in the intake port 21 of each cylinder is rotatably supported via a shaft 55 provided coaxially with the stem portion 7 b of each intake valve 7.
[0065]
Each valve body 51 is disposed immediately above the umbrella portion 7 a of each intake valve 7. The tumble control valve 50 can be switched between a position where the combustion chamber center side of the intake port 21 is shielded to cause reverse tumble, and a position where forward tumble occurs without shielding the combustion chamber center side of the intake port 21.
[0066]
Each shaft 55 is rotationally driven via an actuator (not shown). The control unit 49 that controls the operation of the actuator drives the tumble control valve 50 to a position that shields the combustion chamber center side of the intake port 21 in the stratified combustion region where the engine load and the rotational speed are not more than predetermined values. Causes reverse tumble in the flow. On the other hand, the tumble control valve 50 is driven to a position where the combustion chamber center side of the intake port 21 is not shielded in a homogeneous combustion region where the engine load or the rotational speed rises above a predetermined value, thereby causing forward tumble in the intake air flow. To do.
[0067]
Next, the embodiment shown in FIGS. 8 and 9 will be described. The parts corresponding to those in FIGS. 1 and 3 are denoted by the same reference numerals.
[0068]
In the present embodiment, the tumble control valve 60 that adjusts the flow direction of intake air introduced from the intake port 21 into the combustion chamber 3 includes a valve body 61 interposed in the intake port 21. The semi-disc shaped valve body 61 is rotatably supported via a common shaft 65 that passes through each intake port 21.
[0069]
The shaft 65 is provided in parallel with a crankshaft (not shown). Thereby, the rotation center line of the tumble control valve 60 is substantially orthogonal to the passage center line of the intake port 21 on the plan view.
[0070]
Each valve body 61 is disposed immediately above the umbrella portion 7 a of each intake valve 7. A groove 62 that engages with the stem portion 7 b of the intake valve 7 is formed in the valve body 61. When the tumble control valve 60 rotates about the shaft 65, the valve body 61 does not collide with the stem portion 7 b of the intake valve 7.
[0071]
Each valve body 61 is disposed immediately above the umbrella portion 7 a of each intake valve 7. The tumble control valve 60 is switched between a position where the combustion chamber center side of the intake port 21 is shielded to cause reverse tumble and a position where the combustion chamber center side of the intake port 21 is not shielded to generate forward tumble.
[0072]
Each shaft 65 is rotationally driven via an actuator (not shown). The control unit 49 for controlling the operation of the actuator drives the tumble control valve 60 to a position where the combustion chamber center side of the intake port 21 is shielded in the stratified combustion region where the engine load and the rotational speed are equal to or less than predetermined values. Causes reverse tumble in the flow. On the other hand, the tumble control valve 60 is driven to a position where the combustion chamber center side of the intake port 21 is not shielded in a homogeneous combustion region where the engine load or the rotational speed rises above a predetermined value, thereby causing forward tumble in the intake air flow. To do.
[0073]
The tumble control valve 60 has a high degree of freedom with respect to the shape of the valve body 61, and the setting range such as the strength of reverse tumble is expanded.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an engine showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the engine.
FIG. 3 is a schematic plan view of the engine.
FIG. 4 is a cross-sectional view of the engine in the stratified charge combustion region.
FIG. 5 is a cross-sectional view of the engine in a homogeneous combustion region.
FIG. 6 is a cross-sectional view of an engine showing another embodiment.
FIG. 7 is a schematic plan view of the engine.
FIG. 8 is a cross-sectional view of an engine showing still another embodiment.
FIG. 9 is a schematic plan view of the engine.
FIG. 10 is a cross-sectional view of an engine showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Piston 2 Cylinder head 3 Combustion chamber 4 Spark plug 6 Injector 7 Intake valve 8 Exhaust valve 20 Combustion chamber ceiling wall 21 Intake port 22 Exhaust port 25 Inclined surface 26 Inclined surface 30 Piston crown part 31 Cavity 40 Tumble control valve 41 Valve body 44 Outer peripheral surface 43 Recess 45 Shaft 50 Tumble control valve 51 Valve body 55 Shaft 60 Tumble control valve 61 Valve body 65 Shaft

Claims (5)

An intake port for introducing intake air into the cylinder;
An intake valve that opens and closes the intake port in synchronization with the engine rotation;
An injector for injecting fuel into the cylinder;
A spark plug that ignites the air-fuel mixture in the cylinder;
In-cylinder direct injection spark ignition engine with
The intake port has a port shape that causes forward tumble in the intake flow,
A tumble that includes a cylindrical valve body having a groove that engages with a stem portion of the intake valve and shields the combustion chamber center side of the intake port according to operating conditions to cause a reverse tumble in the intake air flow. In-cylinder direct injection spark ignition engine characterized by having a control valve. Substantially is perpendicular to the passage center line of the intake port in plan diagram the center line of the data down Blu control valve,
While forming an outer peripheral surface protruding from the wall surface of the intake port on the valve body,
The in-cylinder direct injection spark ignition engine according to claim 1, wherein a concave portion that is curved along the wall surface of the intake port is formed in the valve body. An intake port for introducing intake air into the cylinder;
An intake valve that opens and closes the intake port in synchronization with the engine rotation;
An injector for injecting fuel into the cylinder;
A spark plug that ignites the air-fuel mixture in the cylinder;
In-cylinder direct injection spark ignition engine with
The intake port has a port shape that causes forward tumble in the intake flow,
The valve body interposed in the intake port is rotatably supported via a shaft provided coaxially with the stem portion of the intake valve, and rotates according to operating conditions so that the combustion chamber center side of the intake port is located. shielding to tumble control cylinder direct injection spark ignition engine you characterized by <br/> with a valve to rise to reverse tumble to the intake flow. The intake valve has an umbrella seated in the opening of the intake port with respect to the combustion chamber ceiling wall;
The in-cylinder direct injection spark ignition engine according to any one of claims 1 to 3, wherein the tumble control valve is disposed in an intake port directly above an umbrella portion of the intake valve. The fuel injection timing of the injector is set to the intake stroke at high load,
The direct injection spark ignition engine according to any one of claims 1 to 4 , wherein the fuel injection timing of the injector is set to a compression stroke at a low load.

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