JP2013087628A - Engine with exhaust gas recirculating device - Google Patents

Abstract

[PROBLEMS] To improve the knocking performance by improving the swirlability of EGR gas in a combustion chamber, and to ensure the output at a high rotation speed.
A single cylinder is provided with two intake valves 3, 4 and two exhaust valves 5, 6 and a spark plug 9 is disposed at the center of a combustion chamber 8, and a part of the exhaust is taken in an intake passage. The engine 1 having the EGR device 22 to be introduced to the engine 1 includes a normal opening / closing mode in which all of the two intake valves 3, 4 and the two exhaust valves 5, 6 are opened and closed, and the first intake valve 3 and the second intake valve 3. The EGR device 22 can be switched to a partial open / close mode in which the exhaust valve 6 is opened and closed to generate a swirl in the intake air in the combustion chamber 8, and the EGR device 22 follows the swirl turning direction toward the outer peripheral portion of the combustion chamber 8. Thus, the discharge direction of EGR gas is set. The partial opening / closing mode is selected at a predetermined low rotation, and the normal opening / closing mode is selected at a predetermined high rotation.
[Selection] Figure 3

Description

  The present invention relates to an engine equipped with an exhaust gas recirculation device, and more particularly to a technique for improving anti-knocking performance.

An engine mounted on a vehicle or the like is widely equipped with an exhaust gas recirculation device (EGR device). The EGR device has a function of reducing the combustion temperature by recirculating a part of the exhaust gas to the intake passage, thereby suppressing emission of nitrogen oxide (NOx) from the engine.
Further, a technique for reducing engine knock using exhaust gas (EGR gas) recirculated to the intake passage by the EGR device has been proposed.

  In such a technique, an exhaust port of the EGR gas to the intake passage is installed in the vicinity of the combustion chamber, and the direction of the exhaust port is set so that the EGR gas follows the inner peripheral wall of the cylinder. As a result, EGR gas, which is an inert gas, swirls along the inner peripheral wall of the cylinder, an annular EGR gas layer is formed in the combustion chamber, and good ignition is achieved in the ignition device disposed in the approximate center of the cylinder head. While ensuring the performance, it is possible to suppress self-ignition of the end gas in the vicinity of the cylinder inner peripheral wall and reduce knocking (Patent Document 1).

JP 62-131961 A

  By the way, in recent years, in order to improve the output performance in a high rotation range, multi-valve engines having a plurality of intake valves and exhaust valves in one cylinder are increasing. In particular, in an engine mounted on a vehicle, a four-valve engine having two intake valves and two exhaust valves in each cylinder has become the mainstream in view of the improvement in output due to the multi-valve and the complicated structure.

In such a four-valve engine, when the technique of the above-mentioned patent document is applied, the EGR gas that attempts to swivel along the inner wall surface of the cylinder is almost exhausted from one of the two exhaust valves that reaches first. Therefore, it is difficult for the EGR gas to turn over the entire circumference along the inner peripheral wall of the cylinder, and it may be difficult to sufficiently suppress knocking.
The present invention has been made to solve such problems. The object of the present invention is to improve the anti-knocking performance by improving the swirlability of EGR gas in the combustion chamber, and at high revolutions. Is to provide an engine with an exhaust gas recirculation device capable of ensuring the output of

  In order to achieve the above object, an engine with an exhaust gas recirculation device according to claim 1 is provided with a plurality of intake valves and exhaust valves in one cylinder, an ignition means is disposed in the center of the combustion chamber, and An engine with an exhaust gas recirculation device provided with an exhaust gas recirculation means for introducing a part of the air into the intake passage, the normal open / close mode for opening and closing all of the multiple intake valves and exhaust valves, and one of the multiple intake valves and exhaust valves. And a switching means that can be switched to a partial opening and closing mode for generating a swirl in the intake air in the combustion chamber, and the exhaust gas recirculation means so as to follow the swirling direction of the swirl toward the outer periphery of the combustion chamber The exhaust gas discharge direction to the intake passage is set, and a part of the exhaust gas is introduced into the intake passage when the switching means switches to the partial opening / closing mode.

The engine with an exhaust gas recirculation device according to claim 2 is characterized in that, in claim 1, the partial opening / closing mode is selected when the engine speed is a predetermined low speed, and the normal opening / closing mode is selected when the engine speed is high. .
An engine with an exhaust gas recirculation device according to a third aspect is the engine according to the second aspect, wherein two intake valves and two exhaust valves are provided for each cylinder, and in the partial opening / closing mode, the engine is opposed to each other across the central portion of the combustion chamber. A pair of intake valves and exhaust valves arranged at the corners open and close.

According to a fourth aspect of the present invention, there is provided an engine with an exhaust gas recirculation device according to any one of the first to third aspects, wherein at least the exhaust gas is exhausted by the exhaust gas recirculation means along the intake valve side wall that opens and closes in the intake passage. A partition wall extending downstream from the discharge position is provided.
An engine with an exhaust gas recirculation device according to claim 5 is the engine according to claim 4, wherein the end of the partition downstream of the intake air is positioned radially outside the cylinder guide from the valve guide of the intake valve that opens and closes in the partial open / close mode. Features.

An engine with an exhaust gas recirculation device according to claim 6 is the engine according to claim 4 or 5, wherein an end of the upstream side of the partition wall is located in the intake passage so that intake air flows between the partition wall and the side wall of the intake passage. It is characterized by opening.
The engine with an exhaust gas recirculation device according to claim 7 is the engine according to claim 6, wherein the cross-sectional area of the passage between the partition wall and the side wall of the intake passage is set to be smaller on the intake downstream side than on the intake upstream side. It is characterized by that.

  An engine with an exhaust gas recirculation device according to an eighth aspect of the present invention advances the ignition timing when the exhaust gas is introduced into the intake passage by the exhaust gas recirculation device in the partial opening / closing mode according to any one of the first to seventh aspects. The ignition timing control means is provided.

  According to the first aspect of the present invention, when the partial opening / closing mode is selected, a part of the intake valve and the exhaust valve is opened and closed, and swirl is generated in the intake air in the combustion chamber. Exhaust gas (hereinafter referred to as EGR gas) introduced into the intake passage by the exhaust gas recirculation means swirls together with the intake swirl, and a layer having a high exhaust concentration is formed at the outer periphery of the combustion chamber. In the central part of the combustion chamber where the ignition means is disposed, the exhaust concentration is relatively low, and ignition performance can be ensured. At the outer peripheral part of the combustion chamber, the end gas combustibility is lowered by EGR gas and self-ignition is performed. It is possible to make the engine difficult to knock and difficult to knock.

  According to the second aspect of the present invention, the partial opening / closing mode is selected at a predetermined low speed, and a part of the intake valve and the exhaust valve is opened / closed to generate a swirl in the intake air in the combustion chamber. In addition, the normal opening / closing mode is selected at a predetermined high speed, and all of the plurality of intake valves and exhaust valves are opened / closed. Therefore, the opening area can be increased by the multi-valve, and sufficient output performance can be ensured.

  In this way, swirl is generated in the combustion chamber by opening and closing some of the plurality of intake valves and exhaust valves during low rotation, which is generally easy to knock, and swirling of EGR gas in the combustion chamber by this swirl. It is possible to improve the performance and suppress knocking, and at the time of high rotation that is difficult to knock, all the intake valves and exhaust valves can be opened and closed to ensure output performance and anti-knock performance And ensuring output can be achieved at the same time.

  According to the invention of claim 3, a pair of intake valves and exhaust valves are provided in each cylinder, and in the partial opening / closing mode, a pair of intake valves disposed diagonally with respect to the center of the combustion chamber, and Since the exhaust valve opens and closes, swirl can be generated in a large range in the circumferential direction in the combustion chamber from the intake valve toward the diagonal exhaust valve. As a result, it is possible to form a layer having a high exhaust concentration in the outer peripheral portion of the combustion chamber in a large peripheral range, and in the partial opening / closing mode at low rotation, the anti-knocking performance can be improved as compared with the normal opening / closing mode.

According to the invention of claim 4, since the intake passage is provided with the partition wall extending from the EGR gas discharge position by the exhaust gas recirculation means to the intake downstream side along the side wall on the intake valve side that opens and closes in the partial open / close mode. An inlet path for efficiently introducing EGR gas toward the outer peripheral portion of the combustion chamber while preventing diffusion of EGR gas can be formed between the side wall of the intake passage and the side wall of the intake passage.
According to the fifth aspect of the present invention, the end portion of the partition wall on the intake downstream side is located on the radially outer side of the cylinder from the valve guide of the intake valve that opens and closes in the partial opening / closing mode. The EGR gas passing through the gas passes outside the valve guide of the intake valve, and the EGR gas can be reliably introduced toward the outer peripheral portion of the combustion chamber.

  According to the sixth aspect of the present invention, the intake upstream end of the partition wall is opened in the intake passage so that the intake air flows between the partition wall and the side wall of the intake passage. The provision of the intake passage does not reduce the cross-sectional area of the intake passage, and the intake flow rate can be sufficiently ensured at high revolutions. Further, the flow rate of the EGR gas passing through the passage between the partition wall and the side wall of the intake passage can be increased by intake air, and the EGR gas can be swirled greatly in the circumferential direction in the combustion chamber.

According to the invention of claim 7, since the cross-sectional area of the passage between the partition wall and the side wall of the intake passage is smaller on the intake downstream side than on the intake upstream side, the intake air passing through this passage is directed toward the downstream side. To increase the flow velocity. Therefore, the flow rate of the intake air is increased at the outer peripheral portion of the combustion chamber, and the EGR gas can be further swirled in the combustion chamber.
According to the eighth aspect of the present invention, it is possible to advance the ignition timing at low revolutions by improving the anti-knocking performance by turning the EGR gas at the outer periphery of the combustion chamber in the partial open / close mode, thereby improving the combustibility. It is possible to improve and reduce fuel consumption.

1 is a schematic structural diagram of an engine with an exhaust gas recirculation device according to a first embodiment of the present invention. 1 is a cross-sectional view showing a schematic configuration of an intake / exhaust system of an engine according to a first embodiment of the present invention. It is a cross-sectional view showing the flow direction of intake air in the combustion chamber in the two-valve open / close mode. It is a flowchart which shows the control point of knocking avoidance control in ECU. It is a graph which shows a knocking avoidance control area. It is a cross-sectional view which shows schematic structure of the intake / exhaust system of the engine of the 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic structural diagram of an engine with an exhaust gas recirculation device (hereinafter referred to as engine 1) according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a schematic configuration of the intake and exhaust system of the engine 1 according to the first embodiment of the present invention. In FIG. 2, the flow direction of the intake air in the combustion chamber 8 in a four-valve open / close mode described later is indicated by a white arrow.

As shown in FIGS. 1 and 2, an engine 1 according to the first embodiment of the present invention includes a cylindrical cylinder 2 with two intake valves (a first intake valve 3 and a second intake valve 4). This is a four-valve engine provided with two exhaust valves (first exhaust valve 5 and second exhaust valve 6).
The cylinder head 7 of the engine 1 is provided with a spark plug 9 (ignition means) at a substantially central portion facing the combustion chamber 8. The lower surface of the cylinder head 7 is gently inclined downward from the ridgeline at the substantially central portion toward both sides to form a pent roof type combustion chamber. Two intake ports 10 are arranged on one slope of the lower surface of the cylinder head 7, and two exhaust ports 11 are arranged on the other slope. The intake port 10 is provided with intake valves 3, 4, and the exhaust port 10 is provided with exhaust valves 5, 6. These intake valves 3, 4 and exhaust valves 5, 6 are not shown on the cylinder head 7. The mechanism is driven to open and close in synchronization with the rotation of the crankshaft.

An intake manifold 15 (intake passage) connected to the two intake ports 10 and an exhaust manifold 16 connected to the two exhaust ports 11 are connected in the vicinity of the ports 10 and 11 and formed in a Y shape. ing.
The intake manifold 15 is provided with a fuel injection valve 17 that injects fuel to intake air that passes through the intake manifold 15. The fuel injection valve 17 is supplied with fuel from a fuel tank 18 by a feed pump 19. The fuel injection valve 17 can inject fuel toward the two intake ports 10 and can inject fuel only toward the intake port 10 including the first intake valve 3. In addition, the fuel injection direction can be switched.

Further, the engine 1 is provided with an EGR device 21 (exhaust gas recirculation means).
The EGR device 21 includes an EGR passage 22 and an EGR valve 23 that opens and closes the EGR passage 22. The EGR passage 22 has one end 22a connected to the intake manifold 15 and the other end 22b connected to the exhaust manifold 16 of the engine 1 or an exhaust passage downstream thereof. The EGR device 21 has a function of opening part of the EGR valve 23 to recirculate a part of the exhaust gas into the intake manifold 15 as EGR gas and lowering the combustion temperature of the engine 1 to suppress NOx emission.

In particular, in the present embodiment, the EGR passage 21 is connected to the intake manifold 15 in the vicinity of one of the two intake valves 3, 4 and the first intake valve 3 of the intake manifold 15. One end portion 22a of the EGR passage 22 is arranged so that EGR gas is discharged along the side wall 15a on the side toward the combustion chamber 8.
In the present embodiment, the valve mechanism for opening and closing the intake valves 3 and 4 and the exhaust valves 5 and 6 is a four valve that opens and closes the two intake valves 3 and 4 and the two exhaust valves 5 and 6 in one cylinder. Switching between the open / close mode (normal open / close mode) and the two-valve open / close mode (partial open / close mode) in which the intake valves 3 and 4 and the exhaust valves 5 and 6 are closed one by one and opened and closed one by one is switched by an actuator not shown. Possible functions are provided.

  In the above four-valve open / close mode, as shown in FIG. 2, since the two intake valves 3, 4 and the two exhaust valves 5, 6 are opened and closed in one cylinder, the intake valves 3, 4 and the exhaust valves 5, 6 are opened. During the valve overlap when both valves open, the intake air flowing in from the two intake valves 3 and 4 moves substantially linearly toward the exhaust valves 5 and 6 facing each other, and the exhaust gas remaining in the combustion chamber 8 is quickly exhausted. It is discharged from the valves 5 and 6.

FIG. 3 is a top view showing the flow direction of the intake air in the combustion chamber 8 in the two-valve open / close mode. In FIG. 3, the flow direction of the intake air is indicated by a white arrow, and the flow direction of the EGR gas is indicated by a solid black arrow.
In the two-valve open / close mode, as shown in FIG. 3, the first intake valve 3 close to the one end portion 22 a of the EGR passage 22 is opened and closed, and the second exhaust gas that is diagonally opposite the first intake valve 3. The valve 6 is opened and closed, and the second intake valve 4 and the first exhaust valve 5 are closed. In the two-valve open / close mode, the injection direction of the fuel injection valve 17 may be controlled so that fuel is not injected toward the second intake valve 4 to be closed.

  The ECU 30 (switching means) includes a crank angle sensor 31 that detects the crank angle of the engine 1, an airflow sensor 32 that detects the intake air flow rate, a throttle sensor that detects the throttle opening, an accelerator position sensor that detects the accelerator operation amount, and the like. Based on information from these sensors, the fuel injection amount by the fuel injection valve 17, the fuel injection timing, the ignition timing by the spark plug 9, and the opening / closing of the EGR valve 23 are controlled based on information from these sensors. To do.

Further, in the present embodiment, the ECU 30 controls the operation of the actuator of the valve mechanism that opens and closes the intake valves 3 and 4 and the exhaust valves 5 and 6 based on the rotational speed and volumetric efficiency of the engine 1. Knocking avoidance control that controls ignition timing and suppresses knocking by EGR gas is enabled.
FIG. 4 is a flowchart showing a control procedure for knocking avoidance control in the ECU 30. FIG. 5 is a graph showing a knocking avoidance control region. FIG. 5 shows an example of an EGR introduction switching line, a valve opening / closing number switching line, and a knocking generation line based on the engine rotational speed and volumetric efficiency.

The routine shown in FIG. 4 is repeatedly performed when the engine is operating.
First, in step S10, volume efficiency is calculated. The volumetric efficiency is calculated from the rotational speed of the engine 1 based on the crank angle transition input from the crank angle sensor 31 and the intake air flow rate detected by the airflow sensor 32. Then, the process proceeds to step S20.
In step S20, an EGR introduction area is determined. Specifically, an EGR introduction switching line as shown in FIG. 5 is set. The EGR introduction switching line is a line serving as a threshold value for switching between EGR introduction and non-introduction according to the engine rotation speed and volumetric efficiency. From the EGR introduction switching line, an EGR cut area where EGR gas is not introduced on the high rotation and high load side, and an EGR introduction area on the low rotation and low load side. Note that an EGR cut region is provided at the time of extremely low load and low rotation close to the idling state in order to ensure stable operation of the engine. Then, the process proceeds to step S30.

  In step S30, a two-valve region is determined. Specifically, a valve opening / closing number switching line as shown in FIG. 5 is set. The valve opening / closing number switching line is a line where the intake air amount is the same, and is a line serving as a threshold for switching between the two-valve opening / closing mode and the four-valve opening / closing mode according to the engine speed and volumetric efficiency. is there. From the valve opening / closing number switching line, the high rotation side is a four-valve region (four-valve opening / closing mode), and the low rotation side is a two-valve region (two-valve opening / closing mode). Then, the process proceeds to step S40.

In step S40, it is determined whether or not the rotational speed of the engine 1 and the volume efficiency calculated in step S10 are in the two-valve region determined in step S30. If it is in the two-valve region, the process proceeds to step S50. If not in the two-valve region, the process proceeds to step S80.
In step S50, the second intake valve 4 and the first exhaust valve 5 are closed, and the two-valve open / close mode for opening and closing the first intake valve 3 and the second exhaust valve 6 is executed. Then, the process proceeds to step S60.

In step S60, it is determined whether or not EGR is introduced. Specifically, it is determined whether or not the rotational speed of the engine 1 and the volumetric efficiency calculated in step S10 are within the EGR introduction region determined in step S20. If it is in the EGR introduction area, the process proceeds to step S70. If it is not the EGR introduction area, this routine is returned.
In step S70, the ignition timing is controlled to advance from the normal time (ignition timing control means). Then, this routine is returned.

In step S80, a four-valve operation for opening and closing all the two intake valves 3, 4 and the two exhaust valves 5, 6 is executed. Then, this routine is returned.
By controlling as described above, in the present embodiment, switching control between the above-described two-valve open / close mode and four-valve open / close mode is performed when EGR is introduced based on the volumetric efficiency and the engine rotation speed.
By setting the two-valve open / close mode, the intake air flows from the first intake valve 3 into the combustion chamber 8 and is discharged from the second exhaust valve 6 diagonally opposite the first intake valve 3. Therefore, a large swirl is generated in the intake air in the combustion chamber 8.

At this time, when the EGR valve 23 is opened and the EGR gas flows into the intake manifold 15, the EGR gas swirls along the inner peripheral wall of the cylinder 2, and an annular EGR gas layer is formed on the outer peripheral portion in the combustion chamber 8. Is formed.
By the way, when the engine 1 is knocked, when the air-fuel mixture is ignited by the spark plug 9 disposed at the substantially central portion of the combustion chamber 8, the flame spreads to the surroundings while generating heat from the spark plug 9. It is generated when the end gas in the vicinity of the inner peripheral wall is compressed and self-ignited. Note that knocking occurs, for example, on the higher load side than the knocking generation line in FIG.

On the other hand, in this embodiment, since the layer of EGR gas with low combustibility is formed along the inner peripheral wall of the cylinder 2 as described above, the air-fuel mixture in the end gas portion is difficult to self-ignite, and knocking is prevented. It is suppressed.
Further, since the EGR gas layer is formed in an annular shape, the concentration of the EGR gas is kept low in the vicinity of the spark plug in the substantially central portion of the combustion chamber 8 to ensure ignitability.

  In addition, since the knocking is suppressed by the two-valve open / close mode and the setting of the discharge direction of the EGR gas as described above, the ignition timing can be advanced. In this embodiment, when EGR gas is introduced in the two-valve open / close mode, the ignition timing is advanced (the knocking avoidance control region indicated by hatching in FIG. 5). Even in a region where normal knocking occurs at low rotation and high load, the anti-knocking performance is improved by using the two-valve open / close mode and EGR gas as described above, so that the ignition timing can be advanced and the advance of the engine 1 can be controlled. Combustibility can be improved and fuel consumption can be improved.

  In this embodiment, switching between the two-valve open / close mode and the four-valve open / close mode is performed based on the engine speed and the volumetric efficiency, and the two-valve open / close mode is selected at the time of low rotation. Therefore, knocking is suppressed at the time of low rotation and high load where knocking is likely to occur. On the other hand, the four-valve opening / closing mode is selected at the time of high rotation at which knocking is unlikely to occur, and the output performance can be ensured by exhibiting the effect of the multi-valve.

FIG. 6 is a cross-sectional view showing a schematic configuration of an intake / exhaust system of an engine according to a second embodiment of the present invention.
The engine 1 according to the second embodiment of the present invention differs from the first embodiment in that a partition wall 40 is provided in the intake manifold 15.
The partition wall 40 extends along the side wall 15 a of the intake manifold 15 from the position facing at least one end portion 22 a of the EGR passage 22 to the intake downstream side, and the EGR gas flows between the partition wall 40 and the side wall 15 a of the intake manifold 15. A passage 41 is formed. A tip 40 a on the intake downstream side of the partition wall 40 extends to the vicinity of the first intake valve 3 and is disposed so as to be positioned on the radially outer side of the cylinder 2 from the valve guide 3 a of the first intake valve 3. The EGR gas flowing in from the EGR passage 22 passes through the passage 41 between the partition wall 40 and the side wall 15a of the intake manifold 15 and the opening of the first intake valve 3, and burns toward the vicinity of the inner peripheral wall of the cylinder 2. It flows into the chamber 8. Furthermore, the passage 41 between the partition wall 40 and the side wall 15a of the intake manifold 15 is opened so that a part of the intake air that passes through the intake manifold 15 flows on the upstream side. The partition wall 40 is disposed so as to be inclined so that the cross-sectional area of the passage 41 between the partition wall 40 and the side wall 15a of the intake manifold 15 decreases from the intake upstream side toward the downstream side.

With the above configuration, in the second embodiment, diffusion of the EGR gas that has flowed into the intake manifold 15 from the EGR passage 22 is suppressed by the partition wall 40. Thereby, an annular layer of EGR gas can be formed at a higher concentration on the outer peripheral portion in the combustion chamber 8.
Further, the tip 40a on the intake downstream side of the partition 40 extends to the vicinity of the first intake valve 3 and is located outside the valve guide 3a of the first intake valve 3, so that the partition 40 and the side wall 15a of the intake manifold 15 are provided. The EGR gas that has passed through the passage 41 between the first intake valve 3 and the first intake valve 3 passes outside the valve guide 3 a of the first intake valve 3 and is introduced along the inner peripheral wall of the cylinder 2. An annular layer of EGR gas can be formed at a higher concentration.

  Further, the passage 41 between the intake manifold 15 and the side wall 15a is opened on the intake upstream side in the intake passage so that the intake air flows into the passage 41. A sufficient intake flow rate can be ensured during high rotation without reducing the area. Further, the flow rate of the EGR gas flowing into the combustion chamber 8 along with the intake air passing through the passage 41 can be increased, and the EGR gas can be swirled greatly on the outer peripheral portion of the combustion chamber 8.

  Further, since the cross-sectional area of the passage 41 between the partition wall 40 and the side wall 15a decreases from the intake upstream side toward the downstream side, the intake air passing through the passage 41 can increase the flow velocity toward the downstream side. . Therefore, the flow rate of the intake air is increased at the outer peripheral portion of the combustion chamber 8, and the EGR gas that flows in along the inner peripheral wall of the cylinder 2 can be further swirled in the combustion chamber 8. As described above, in the present embodiment, an annular layer of EGR gas is formed more strongly in the combustion chamber 8, and an engine that is less likely to cause knocking can be obtained.

In addition, this invention is not limited to the above embodiment.
For example, in the above embodiment, the EGR passage 22 may further include an EGR cooler. Thus, by providing the EGR cooler, it becomes possible to lower the temperature of the EGR gas, so that the air-fuel mixture is less likely to self-ignite at the outer peripheral portion of the combustion chamber 8, and the anti-knocking performance is further improved. Can do.

In addition, a pump for discharging EGR gas may be further provided in the EGR passage 22. By providing the pump in the EGR passage 22 in this manner, the EGR gas can be strongly pushed out into the intake manifold 15 toward the outer peripheral portion of the combustion chamber 8 to greatly swirl the EGR gas in the combustion chamber 8, and the combustion An annular layer of EGR gas can be formed more strongly in the chamber 8.
Further, the present invention is applicable to any engine that has a plurality of intake valves and exhaust valves, can close a part of the intake valves and exhaust valves to generate swirl in the combustion chamber, and has an EGR device. Can be widely applied.

Reference Signs List 1 engine 3 first intake valve 3a valve guide 4 second intake valve 5 first exhaust valve 6 second exhaust valve 8 combustion chamber 9 spark plug 15 intake manifold 21 EGR device 30 ECU
40 Bulkhead

Claims (8)

An engine equipped with an exhaust gas recirculation device comprising a plurality of intake valves and exhaust valves in a single cylinder, an ignition device disposed in the center of the combustion chamber, and an exhaust gas recirculation device for introducing part of the exhaust gas into the intake passage There,
A normal opening / closing mode for opening / closing all of the plurality of intake valves and exhaust valves, and a partial opening / closing mode for opening / closing some of the plurality of intake valves and exhaust valves to generate a swirl in the intake air in the combustion chamber; Switching means that can be switched to,
In the exhaust gas recirculation means, the exhaust gas discharge direction to the intake passage is set so as to follow the swirling direction of the swirl toward the outer peripheral portion of the combustion chamber, and the switching means switches to the partial opening / closing mode. An engine with an exhaust gas recirculation device characterized in that a part of exhaust gas is sometimes introduced into an intake passage.   The engine with an exhaust gas recirculation device according to claim 1, wherein the switching means selects the partial opening / closing mode when the engine speed is a predetermined low speed and selects the normal opening / closing mode when the engine speed is a predetermined high speed. . Two intake valves and two exhaust valves are provided in one cylinder,
3. The engine with an exhaust gas recirculation device according to claim 2, wherein in the partial opening / closing mode, a pair of the intake valve and the exhaust valve that are arranged diagonally with respect to each other with a central portion of the combustion chamber open and close. .   The partition that extends at least from the exhaust discharge position from the exhaust gas recirculation means to the downstream side of the intake gas is provided in the intake passage along a side wall on the intake valve side that opens and closes in the partial open / close mode. The engine with an exhaust gas recirculation device according to any one of 1 to 3.   The engine with an exhaust gas recirculation device according to claim 4, wherein an end portion of the partition wall on the intake downstream side is located on a radially outer side of the cylinder with respect to a valve guide of the intake valve that opens and closes in the partial opening / closing mode.   The end portion on the intake upstream side of the partition wall is opened in the intake passage so that intake air flows between the partition wall and the side wall of the intake passage. The engine with the exhaust gas recirculation device described.   7. The exhaust gas recirculation apparatus according to claim 6, wherein a cross-sectional area of a passage between the partition wall and the side wall of the intake passage is set to be smaller on the intake downstream side than on the intake upstream side. engine.   The ignition timing control stage for advancing the ignition timing when exhaust gas is introduced into the intake passage by the exhaust gas recirculation device in the partial opening / closing mode. An engine with an exhaust gas recirculation device according to claim 1.

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