JP2009041531A - In-cylinder internal combustion engine - Google Patents

Abstract

The present invention relates to an in-cylinder injection internal combustion engine, which enables fine control of the degree of stratification of gas existing in the cylinder, and makes it possible to reduce exhaust emission by utilizing stratification of gas in the cylinder. The purpose is to make possible combustion.
A fuel injection valve 26 for directly injecting fuel into a cylinder of an internal combustion engine 10 is provided. An intake variable valve mechanism 38 and an exhaust variable valve mechanism 40 are provided. An intake side partition wall 30 for partitioning the intake passage 18 into an upper intake passage 18a and a lower intake passage 18b is provided. An exhaust side partition wall 34 for partitioning the exhaust passage 20 into an upper exhaust passage 20a and a lower exhaust passage 20b is provided. Control is performed so that the exhaust valve 24 is opened during a predetermined period during the intake stroke under specific operating conditions where the in-cylinder temperature is low. Under the specific operating condition, the intake control valve 32 and the exhaust control valve 36 are controlled so that the upper intake passage 18a and the upper exhaust passage 20a are closed. Fuel is injected toward the internal EGR gas layer.
[Selection] Figure 4

Description

  The present invention relates to a direct injection internal combustion engine that directly injects fuel into a cylinder.

  Conventionally, for example, Patent Document 1 discloses a control device for a cylinder injection internal combustion engine. In this conventional control device, at the time of low rotation and low load, by increasing the valve overlap period, the amount of already burned gas introduced into the cylinder is increased and the amount of internal EGR gas is increased. Furthermore, a weak swirl flow along the cylinder wall surface is generated in the combustion chamber by providing a phase difference in the opening timing of the left and right valves of the intake valve and / or the exhaust valve when the internal EGR gas is increased. . Thus, stable stratified combustion is performed by forming an EGR gas region in the vicinity of the cylinder wall surface facing the combustion injection valve so that EGR gas is not diffused.

JP 2002-242716 A JP 2004-218646 A JP 2001-271688 A JP 2003-193841 A

  In the method using the phase difference between the valve opening timings of the left and right valves according to the conventional technique described above, the stratification of the EGR gas is limited to the one using the swirl flow that flows along the cylinder wall surface. For this reason, the conventional technique described above still leaves room for improvement in terms of enabling fine control of the degree of stratification of the gas present in the cylinder.

  The present invention has been made to solve the above-described problems, and enables fine control of the stratification degree of the gas existing in the cylinder, and makes it possible to control the exhaust emission by utilizing the stratification of the gas in the cylinder. It is an object of the present invention to provide a cylinder injection type internal combustion engine that enables combustion with good reduction.

A first invention includes a fuel injection valve arranged to inject fuel directly into a cylinder of an internal combustion engine,
An exhaust variable valve mechanism capable of changing at least the closing timing of the exhaust valve; and
An intake-side partition for dividing the intake passage into an upper intake passage and a lower intake passage;
An exhaust-side partition for dividing the exhaust passage into an upper exhaust passage and a lower exhaust passage;
An intake control valve for opening and closing the upper intake passage and the lower intake passage;
An exhaust control valve for opening and closing the upper exhaust passage and the lower exhaust passage;
Valve timing control means for controlling the exhaust valve to be opened during a predetermined period during the intake stroke under specific operating conditions where the in-cylinder temperature is low;
The intake control valve is controlled so that the upper intake passage or the lower intake passage is closed under the specific operating condition, and the upper exhaust passage or the lower exhaust passage is closed. Airflow control means for controlling the exhaust control valve;
It is characterized by providing.

Further, the second invention further comprises an intake variable valve mechanism that makes it possible to change at least the opening timing of the intake valve in the first invention,
Under the specific operating conditions, the valve timing control means is in an open state with the exhaust valve already open during the period from exhaust top dead center to 30 ° CA after exhaust top dead center. The intake variable valve mechanism is controlled as described above.

In a third aspect based on the first or second aspect, the air flow control means controls the intake control valve and the exhaust control valve so that the upper intake passage and the upper exhaust passage are closed. And
The fuel injection valve is arranged with the injection hole directed toward the exhaust side.

According to a fourth aspect of the present invention, in the first or second aspect of the invention, the airflow control means is configured so that the upper intake passage and the lower exhaust passage are closed, or the lower intake passage and the upper intake passage. Controlling the intake control valve and the exhaust control valve so that the exhaust passage is closed;
The fuel injection valve is arranged so that fuel is injected toward the internal EGR gas flowing into the cylinder,
The in-cylinder injection internal combustion engine further includes injection timing control means for controlling the fuel injection valve so that fuel is injected during a period in which the exhaust valve is open during the intake stroke.

According to a fifth aspect of the present invention, in the first or second aspect, the air flow control means includes the intake control valve and the exhaust control valve so that the lower intake passage and the lower exhaust passage are closed. Control
The fuel injection valve is arranged so that fuel is injected toward the vicinity of the spark plug,
The in-cylinder injection internal combustion engine further includes injection timing control means for controlling the fuel injection valve so that fuel is injected in the first half of the intake stroke.

In a sixth aspect based on the first or second aspect, the air flow control means controls the intake control valve and the exhaust control valve so that the upper intake passage and the upper exhaust passage are closed. And
The fuel injection valve is arranged with the injection hole directed toward the intake side.

  According to the first aspect of the present invention, the partition walls, the intake control valve, and the exhaust control valve disposed on both the intake side and the exhaust side are used in a state where both the intake valve and the exhaust valve are opened during the intake stroke. Thus, by controlling the flow of the air sucked into the cylinder and the internal EGR gas, fine control of the degree of stratification of the gas existing in the cylinder can be realized. And, by injecting fuel toward the high-temperature gas stratified by the fuel injection valve, the exhaust emission is reduced by using the stratification of the gas in the cylinder under specific operating conditions where the cylinder temperature is low The combustion which can aim at favorable is attained.

  According to the second invention, during the period from exhaust top dead center to 30 ° CA after exhaust top dead center, the intake valve is opened together with the exhaust valve that is already open, thereby allowing internal EGR. The gas is pre-stratified so that mixing of the gas in the cylinder can be suppressed. Thereby, the inhomogeneity (stratification degree) of air and internal EGR gas can fully be raised.

  According to the third invention, in the cylinder, air is effectively stratified in the region near the intake valve and the internal EGR gas is effectively stratified in the region near the exhaust valve. The fuel is injected toward the stratified high-temperature internal EGR gas region, so that the vaporization of the fuel can be effectively promoted, and under certain operating conditions where the in-cylinder temperature is low. It is possible to reduce the amount of soot (PM) discharged well.

  According to the fourth invention, in the cylinder, air is effectively stratified in the region near the top surface of the intake valve and the piston, and the internal EGR gas is effectively stratified in the region near the exhaust valve and the spark plug. It becomes like this. And by injecting fuel toward the high-temperature internal EGR gas sucked into the cylinder, it is possible to effectively promote the vaporization of the fuel, thereby improving the discharge amount of soot (PM). It becomes possible to reduce. Furthermore, according to the present invention, since the inflow direction of the air from the intake side and the inflow direction of the internal EGR gas from the exhaust side are aligned, the tumble flow is strengthened, so that the internal EGR gas and the fuel are homogeneous. The level can be increased. This makes it possible to satisfactorily reduce NOx emissions and combustion fluctuations.

  According to the fifth invention, the air sucked into the cylinder collides with the internal EGR gas, and a part of the gas is rapidly mixed in the vicinity of the spark plug. Then, fuel is injected toward the air-fuel mixture rapidly mixed in the vicinity of the spark plug. For this reason, the vaporization of fuel can be sufficiently promoted, and the amount of soot (PM) discharged can be satisfactorily reduced.

  According to the sixth invention, in the cylinder, air is effectively stratified in the region close to the intake valve and the internal EGR gas is effectively stratified in the region close to the exhaust valve. The fuel is accelerated by the high-temperature internal EGR gas stratified in the region close to the exhaust valve, and reaches the stratified air in the region close to the intake valve. As described above, the fuel vaporization is effectively promoted, so that the amount of soot (PM) discharged can be favorably reduced. Further, since the fuel is finally burned in the air region on the intake side, it is possible to satisfactorily prevent an increase in HC and CO emissions and fluctuations in combustion due to the fuel being too rich.

Embodiment 1 FIG.
[Description of system configuration]
FIG. 1 is a diagram for explaining the configuration of a direct injection internal combustion engine 10 according to Embodiment 1 of the present invention. A piston 12 that reciprocates inside the cylinder of the internal combustion engine 10 is provided. Further, the internal combustion engine 10 includes a cylinder head 14. A combustion chamber 16 is formed between the piston 12 and the cylinder head 14. An intake passage 18 and an exhaust passage 20 communicate with the combustion chamber 16. An intake valve 22 and an exhaust valve 24 are disposed in the intake passage 18 and the exhaust passage 20, respectively.

  The cylinder head 14 is provided with a fuel injection valve 26 for directly injecting fuel into the cylinder (inside the combustion chamber 16). More specifically, the fuel injection valve 26 of the present embodiment is arranged at a portion below the intake valve 22 in FIG. 1 with the injection hole facing the exhaust side. A spark plug 28 is incorporated in the cylinder head 14 at the center position of the combustion chamber 16.

  An intake side partition wall (tumble plate) 30 for partitioning the intake passage 18 into an upper intake passage 18a and a lower intake passage 18b is disposed at a port portion of the intake passage 18. An intake control valve 32 for opening and closing the upper intake passage 18a and the lower intake passage 18b is disposed at the upstream end of the intake-side partition wall 30.

  Similarly to the intake passage 18 side, an exhaust side partition wall (tumble plate) 34 for dividing the exhaust passage 20 into an upper exhaust passage 20a and a lower exhaust passage 20b is also provided at the port portion of the exhaust passage 20. Has been placed. Further, an exhaust control valve 36 for opening and closing the upper exhaust passage 20a and the lower exhaust passage 20b is disposed at the upstream end of the exhaust side partition wall 34.

  Further, the internal combustion engine 10 is provided with an intake variable valve mechanism 38 that can change the opening / closing timing of the intake valve 22 and an exhaust variable valve mechanism 40 that can change the opening / closing timing of the exhaust valve 24. . The specific configurations of the intake variable valve mechanism 38 and the exhaust variable valve mechanism 40 are not particularly limited. Here, the variable valve mechanisms 38 and 40 drive the intake and exhaust valves 22 and 24 to open and close by electromagnetic force. It shall be an electromagnetically driven valve.

  The system shown in FIG. 1 includes an ECU (Electronic Control Unit) 42. Various sensors for acquiring information related to the operating state of the internal combustion engine 10 are connected to the ECU 42. In addition, the above-described various actuators are connected to the ECU 42. The ECU 42 can control the operating state of the internal combustion engine 10 by controlling the actuators based on the sensor outputs.

[Characteristics of Embodiment 1]
FIG. 2 is a diagram for explaining valve timings of the intake and exhaust valves 22 and 24 used in the first embodiment of the present invention. More specifically, the valve timing (Case I) shown in FIG. 2A shows the valve timing used in the present embodiment under specific operating conditions where the in-cylinder temperature is low, such as during cold start. ing. Further, a valve timing (case II) shown in FIG. 2B indicates a valve timing referred to for comparison with the case I used in the present embodiment.

  Under certain operating conditions such as at the time of start-up where the in-cylinder temperature is low, fuel vaporization becomes insufficient, so that soot (PM) is likely to be generated from the fuel in the droplet state. Therefore, in the present embodiment, the PM amount increases by adopting the valve timing shown in FIG. 2A and adjusting the intake control valve 32 and the exhaust control valve 36, which will be described later with reference to FIGS. An internal EGR gas amount and air (fresh air) distribution are created in the cylinder under specific operating conditions such as at the time of start-up. Then, fuel is injected toward the stratified high temperature region so as to promote fuel vaporization.

  At the valve timing shown in FIG. 2 (A), the exhaust valve 24 is set to be closed at the latter half of the intake stroke after being opened at a predetermined timing before the expansion bottom dead center. More specifically, the closing timing of the exhaust valve 24 is set so as to be closed at a timing near the intake bottom dead center.

  Also, at the valve timing shown in FIG. 2A, the intake valve 22 is opened between exhaust top dead center and exhaust top dead center (ATDC) 30 ° CA (an example shown in FIG. 2A). Is set to open at exhaust top dead center). Further, the closing timing of the intake valve 22 is set so as to be closed earlier than the exhaust valve 24 during the intake stroke. Further, the closing timing of the intake valve 22 is adjusted so as to obtain an optimum EGR rate determined from the combustion surface.

  As described above, at the valve timing shown in FIG. 2 (A), the intake valve 22 and the exhaust valve 24 are simultaneously operated between the exhaust top dead center and the exhaust top dead center (ATDC) 30 ° CA (the first half of the intake stroke). An open state is created. On the other hand, in the valve timing shown in FIG. 2 (B) for comparison, the opening / closing timing of the exhaust valve 24 is the same as the valve timing shown in FIG. 2 (A), but the opening timing of the intake valve 22 is The timing is set to be after 30 ° CA after exhaust top dead center (ATDC).

  FIG. 3 is a diagram showing measurement results of in-cylinder inhomogeneity (stratification degree) when Case I and Case II shown in FIG. 2 are used. As shown in FIG. 3, in the case I (FIG. 2 (A)) used in this embodiment, the gas distribution in the cylinder becomes more inhomogeneous than in the case II (FIG. 2 (B)). The result of increasing the stratification degree of was obtained. This is because, in the case I where the intake valve 22 starts to open before exhaust top dead center (ATDC) 30 ° CA, the intake valve 22 and the exhaust valve 24 are located near the top dead center (TDC) where the gas flow rate is low. It is considered that the internal EGR gas is stratified in advance by opening both together, and mixing of the gas in the cylinder is suppressed.

Next, three methods of in-cylinder gas airflow control using the intake control valve 32 and the exhaust control valve 36 will be described with reference to FIGS.
First, in the control example shown in FIG. 4, the intake control valve 32 is controlled to close the upper intake passage 18a. Further, the exhaust control valve 36 is controlled so as to close the upper exhaust passage 20a.

  As shown in FIG. 4, when the intake control valve 32 and the exhaust control valve 36 are controlled and the intake stroke is started with the valve timing shown in FIG. The gas is filled in the cylinder while the mixing of the gas and the internal EGR gas from the exhaust side is suppressed satisfactorily.

  More specifically, air (fresh air) is introduced into the cylinder through the lower intake passage 18b. At this time, as indicated by arrows in FIG. 4, the air flows in the direction of the axis of the piston 12 along the cylinder wall surface. Further, the internal EGR gas (exhaust gas) is introduced into the cylinder through the lower exhaust passage 20b. At this time, the internal EGR gas flows in the direction of the axis of the piston 12 along the cylinder wall surface, similarly to the intake air. As a result, as shown in FIG. 4, air is effectively stratified in the region close to the intake valve 22 and the internal EGR gas is effectively stratified in the region close to the exhaust valve 24.

  In the control example shown in FIG. 4, the fuel is injected from the fuel injection valve 26 disposed on the intake side toward the internal EGR gas stratified on the side close to the exhaust valve 24. The fuel injection timing in this case is a predetermined timing such as a compression stroke.

  According to the control example shown in FIG. 4 described above, the combination of the valve timing of the intake / exhaust valves 22 and 24 and the tumble plates 30 and 34 for both intake and exhaust causes a highly stratified air and internal An EGR gas distribution can be obtained. And by injecting the fuel toward the stratified high temperature internal EGR gas region, it is possible to effectively promote the vaporization of the fuel, thereby favorably reducing the amount of soot (PM) discharged. It becomes possible.

  Next, in the control example shown in FIG. 5, the intake control valve 32 is controlled so as to close the upper intake passage 18a. Further, the exhaust control valve 36 is controlled so as to close the lower exhaust passage 20b. That is, in this control example, the upper and lower sides of the passages where the intake control valve 32 and the exhaust control valve 36 are respectively closed are staggered.

  When the intake control valve 32 and the exhaust control valve 36 are controlled as shown in FIG. 5 and the intake stroke is started with the valve timing shown in FIG. The cylinder is filled with the gas while the mixing of the gas and the internal EGR gas from the exhaust side is satisfactorily suppressed.

  More specifically, air (fresh air) is introduced into the cylinder through the lower intake passage 18b. At this time, as indicated by arrows in FIG. It flows in the direction of the axis of the piston 12 so as to be along. Further, the internal EGR gas (exhaust gas) is introduced into the cylinder through the upper exhaust passage 20a as shown by an arrow in FIG. At this time, the internal EGR gas flows in the direction of the spark plug 28. As a result, as shown in FIG. 5, the air is effectively stratified in the region close to the top surfaces of the intake valve 22 and the piston 12, and the internal EGR gas is effectively stratified in the region close to the exhaust valve 24 and the spark plug 28, respectively. Will come to be.

  Further, according to the control of the intake control valve 32 and the exhaust control valve 36 as described above, the inflow direction of the air from the intake side and the inflow direction of the internal EGR gas from the exhaust side are aligned. The in-cylinder gas flow (tumble flow) as shown by the counterclockwise arrow is promoted.

  In the control example shown in FIG. 5, the fuel injection timing is the timing at which the exhaust valve 24 is opened during the intake stroke, and the fuel is injected from the fuel injection valve 26 toward the internal EGR gas flowing into the cylinder. Is done.

  Also according to the control example shown in FIG. 5 described above, highly stratified air and internal EGR are formed in the cylinder by setting the valve timings of the intake and exhaust valves 22 and 24 and the tumble plates 30 and 34 for both intake and exhaust. A gas distribution can be obtained. And by injecting fuel toward the high-temperature internal EGR gas sucked into the cylinder, it is possible to effectively promote the vaporization of the fuel, thereby improving the discharge amount of soot (PM). It becomes possible to reduce.

  Further, according to the control example shown in FIG. 5, the tumble flow is enhanced as described above by aligning the inflow direction of air from the intake side and the inflow direction of internal EGR gas from the exhaust side. This increases the homogeneity level of the internal EGR gas and the fuel. This makes it possible to satisfactorily reduce NOx emissions and combustion fluctuations.

  In the control example shown in FIG. 5, the intake control valve 32 is controlled so as to close the upper intake passage 18a, and the exhaust control valve 36 is controlled so as to close the lower exhaust passage 20b. However, the present invention is not limited to this example, and conversely, the intake control valve 32 is controlled to close the lower intake passage 18b, and the exhaust control valve 36 is controlled to close the upper exhaust passage 20a. You may do it. According to such a control example, the distribution of air and internal EGR gas is such that the distribution of air and internal EGR gas shown in FIG. 5 is reversed about the axis of the piston 12 and the air and internal EGR gas are reversed. In addition, the tumble flow opposite to that in FIG. 5 is strengthened. Also in such a control example, similarly, by injecting fuel toward the high-temperature internal EGR gas, the same effect as that of the control example shown in FIG. 5 described above can be achieved.

  Further, in the control example shown in FIG. 5 described above, the valve timing of the intake and exhaust valves 22 and 24 has been described as the valve timing shown in FIG. 2 as in the control example shown in FIG. In the control example shown in FIG. 5, such valve timing is not necessarily required. More specifically, when emphasizing the point that the tumble flow shown in FIG. 5 is strengthened, the opening timing of the intake valve 22 is from exhaust top dead center to exhaust top dead center (ATDC) 30 ° CA. (The first half of the intake stroke) may not be.

  Next, in the control example shown in FIG. 6, the intake control valve 32 is controlled to close the lower intake passage 18b. Further, the exhaust control valve 36 is controlled so as to close the lower exhaust passage 20b. In this case, air (fresh air) is introduced into the cylinder through the upper intake passage 18a, and at this time, the air flows in the direction of the spark plug 28 as shown by an arrow in FIG. Will come to do. Further, the internal EGR gas (exhaust gas) is introduced into the cylinder through the upper exhaust passage 20a. At this time, as indicated by an arrow in FIG. It flows in the direction of the spark plug 28. As a result, as shown in FIG. 6, the air sucked into the cylinder collides with the internal EGR gas, and a part of these gases is rapidly mixed in the vicinity of the spark plug 28. That is, the rapidly mixed air-fuel mixture is distributed in the vicinity of the spark plug 28. Also in this control example, air is effectively stratified in the region close to the intake valve 22 and the internal EGR gas is effectively stratified in the region close to the exhaust valve 24.

  In the control example shown in FIG. 6, the fuel is injected from the fuel injection valve 26 toward the air-fuel mixture rapidly mixed in the vicinity of the spark plug 28. The fuel injection timing in this case is a predetermined timing in the first half of the intake stroke.

  According to the control example shown in FIG. 6 described above, the air and the internal EGR gas are rapidly mixed by setting the valve timing of the intake and exhaust valves 22 and 24 and the combination of the tumble plates 30 and 34 for both intake and exhaust. As a result, the fuel is injected toward the air that is homogeneously mixed with the high-temperature internal EGR gas. For this reason, the vaporization of fuel can be sufficiently promoted, and the amount of soot (PM) discharged can be satisfactorily reduced.

  As described above with reference to the three control examples of FIGS. 4 to 6, the tumble plates 30 and 34 disposed on both the intake side and the exhaust side and the control valves 32 and 36 disposed on the upper ends thereof. By controlling the flow of the air sucked into the cylinder and the flow of the internal EGR gas, fine control of the degree of stratification of the gas existing in the cylinder can be realized. Then, by combining the valve timing settings shown in FIG. 2A, the inhomogeneity (stratification degree) of air and internal EGR gas can be sufficiently increased. According to the above three control examples, it is possible to satisfactorily reduce exhaust emissions such as soot (PM) and NOx by utilizing the stratification of the gas in the cylinder.

In the first embodiment, the ECU 42 sets the intake variable valve mechanism 38 and the exhaust variable valve mechanism 40 so that the valve timings of the intake and exhaust valves 22 and 24 shown in FIG. 2A are obtained. By controlling, the “valve timing control means” in the first invention controls the intake control valve 32 and the exhaust control valve 36 as shown in the control examples shown in FIGS. The “airflow control means” in the invention is realized respectively.
Further, the “injection timing control means” in the fourth aspect of the present invention is realized by the ECU 42 controlling the fuel injection valve 26 so that fuel is injected at the timing shown in the control example shown in FIG.
Further, the “injection timing control means” in the fourth aspect of the present invention is realized by the ECU 42 controlling the fuel injection valve 26 so that fuel is injected at the timing shown in the control example shown in FIG.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 7 is a diagram for explaining a configuration of a direct injection internal combustion engine 50 and a control example thereof according to Embodiment 2 of the present invention. As shown in FIG. 7, in the cylinder injection internal combustion engine 50 of the present embodiment, the fuel injection valve 26 is arranged at a portion below the exhaust valve 24 in FIG. 7 with the injection hole facing the intake side. Yes. Except for this point, the internal combustion engine 50 of the present embodiment is configured in the same manner as the internal combustion engine 10 of the first embodiment described above.

  Also in the control example shown in FIG. 7, it is assumed that the valve timing shown in FIG. 2A described above is used. In this control example, the intake control valve 32 is controlled so as to close the upper intake passage 18a. Further, the exhaust control valve 36 is controlled so as to close the upper exhaust passage 20a.

According to the control method of the intake control valve 32 and the exhaust control valve 36 as described above, as shown in FIG. 7, as in the case of the control example shown in FIG. Then, the internal EGR gas is effectively stratified on the side closer to the exhaust valve 24.
In the control example shown in FIG. 7, the fuel is injected from the fuel injection valve 26 toward the intake side. The fuel injection timing in this case is a predetermined timing such as a compression stroke.

  According to the control example shown in FIG. 7 described above, the combination of the valve timings of the intake / exhaust valves 22 and 24 and the tumble plates 30 and 34 for both intake and exhaust causes a highly stratified air and internal An EGR gas distribution can be obtained. Then, according to the fuel injection method shown in FIG. 7, the fuel is stratified in a region near the intake valve 22 after being vaporized by the high-temperature internal EGR gas stratified in a region near the exhaust valve 24. To reach the conditioned air. As described above, the fuel vaporization is effectively promoted, so that the amount of soot (PM) discharged can be favorably reduced. Further, since the fuel is finally burned in the air region on the intake side, it is possible to satisfactorily prevent an increase in HC and CO emissions and fluctuations in combustion due to the fuel being too rich.

It is a figure for demonstrating the structure of the cylinder injection type internal combustion engine in Embodiment 1 of this invention. It is a figure for demonstrating the valve timing of the intake / exhaust valve used in Embodiment 1 of this invention. It is a figure which shows the measurement result of the inhomogeneity (stratification degree) in a cylinder at the time of using the case I and case II shown in FIG. It is a figure for demonstrating the 1st method of the airflow control of the in-cylinder gas in Embodiment 1 of this invention. It is a figure for demonstrating the 2nd method of the airflow control of the in-cylinder gas in Embodiment 1 of this invention. It is a figure for demonstrating the 3rd method of the airflow control of the in-cylinder gas in Embodiment 1 of this invention. It is a figure for demonstrating the structure of the cylinder injection type internal combustion engine in Embodiment 2 of this invention, and the method of the airflow control of cylinder gas.

Explanation of symbols

10, 50 In-cylinder injection internal combustion engine 12 Piston 16 Combustion chamber 18 Intake passage 18a Upper intake passage 18b Lower intake passage 20 Exhaust passage 20a Upper exhaust passage 20b Lower exhaust passage 22 Intake valve 24 Exhaust valve 26 Fuel injection valve 28 Ignition Plug 30 Inlet side bulkhead (tumble plate)
32 Intake control valve 34 Exhaust side partition (tumble plate)
36 Exhaust control valve 38 Intake variable valve mechanism 40 Exhaust variable valve mechanism 42 ECU (Electronic Control Unit)

Claims (6)

A fuel injection valve arranged to inject fuel directly into the cylinder of the internal combustion engine;
An exhaust variable valve mechanism capable of changing at least the closing timing of the exhaust valve; and
An intake-side partition for dividing the intake passage into an upper intake passage and a lower intake passage;
An exhaust-side partition for dividing the exhaust passage into an upper exhaust passage and a lower exhaust passage;
An intake control valve for opening and closing the upper intake passage and the lower intake passage;
An exhaust control valve for opening and closing the upper exhaust passage and the lower exhaust passage;
Valve timing control means for controlling the exhaust valve to be opened during a predetermined period during the intake stroke under specific operating conditions where the in-cylinder temperature is low;
The intake control valve is controlled so that the upper intake passage or the lower intake passage is closed under the specific operating condition, and the upper exhaust passage or the lower exhaust passage is closed. Airflow control means for controlling the exhaust control valve;
A cylinder injection type internal combustion engine comprising: An intake variable valve mechanism that can change at least the opening timing of the intake valve;
Under the specific operating conditions, the valve timing control means is in an open state with the exhaust valve already open during the period from exhaust top dead center to 30 ° CA after exhaust top dead center. 2. The direct injection internal combustion engine according to claim 1, wherein the intake variable valve mechanism is controlled as described above. The air flow control means controls the intake control valve and the exhaust control valve so that the upper intake passage and the upper exhaust passage are closed;
The in-cylinder injection internal combustion engine according to claim 1 or 2, wherein the fuel injection valve is arranged with an injection hole directed toward an exhaust side. The air flow control means includes the intake control valve and the exhaust control so that the upper intake passage and the lower exhaust passage are closed, or so that the lower intake passage and the upper exhaust passage are closed. Control the valve,
The fuel injection valve is arranged so that fuel is injected toward the internal EGR gas flowing into the cylinder,
The in-cylinder internal combustion engine further includes an injection timing control means for controlling the fuel injection valve so that fuel is injected during a period in which the exhaust valve is open during an intake stroke. The in-cylinder injection internal combustion engine according to 1 or 2. The air flow control means controls the intake control valve and the exhaust control valve so that the lower intake passage and the lower exhaust passage are closed;
The fuel injection valve is arranged so that fuel is injected toward the vicinity of the spark plug,
The in-cylinder injection according to claim 1 or 2, wherein the in-cylinder injection internal combustion engine further includes an injection timing control means for controlling the fuel injection valve so that fuel is injected in the first half of an intake stroke. Internal combustion engine. The air flow control means controls the intake control valve and the exhaust control valve so that the upper intake passage and the upper exhaust passage are closed;
The in-cylinder injection internal combustion engine according to claim 1 or 2, wherein the fuel injection valve is arranged with an injection hole directed toward an intake side.

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