JP3318355B2 - Intake system for direct injection diesel engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for a direct injection diesel engine, and more particularly to an intake system for a direct injection diesel engine in which fuel is directly injected into a combustion chamber by a multi-hole injection nozzle having a plurality of injection holes. Related to the device.

[0002]

2. Description of the Related Art Conventionally, in a diesel engine in which fuel is injected into a cylinder which has been heated to a high temperature, the fuel is spontaneously ignited, and the intake port is formed as a helical port. It has been practiced to enhance the combustion efficiency by promoting the mixing of methane, improve the output, and purify the exhaust by preventing the generation and emission of black smoke. In particular, in a fuel supply type called a direct injection (abbreviated as a direct injection) type in which fuel is directly injected into a combustion chamber without passing through a vortex chamber or a pre-combustion chamber, it is necessary to mix the injected fuel and intake air.

For example, Japanese Patent Application Laid-Open No. Sho 62-174533 discloses a method in which two intake ports are provided in one cylinder, and one of the intake ports is used as a helical port and the other is used as a directional port to eliminate swirl caused by the helical port. FIG. 1 shows a configuration in which air is mainly taken in from a helical port at a low rotation speed and mainly taken from a directional port at a high rotation speed. With this configuration, at the time of low rotation, the swirl by the intake air from the helical port can promote the mixing of the injected fuel and the intake air, thereby increasing the combustion efficiency (air utilization rate). , The cooling loss can be prevented from increasing, the intake efficiency can be improved, and ignition delay can be prevented.

[0004]

However, in the above-described conventional apparatus, a strong swirl is generated even at a low load and a low rotation, the premixed combustion ratio is increased, and the combustion temperature is increased. Since the amount of generated and emitted gas increases and the amount of fuel injection is small in the idling operation range, there is a problem that if the swirl is strong, the fire is extinguished and the idling stability is impaired. In recent years, from the viewpoint of pollution prevention, it has been desired to suppress the characteristic black smoke contained in the exhaust gas of a diesel engine (which is generated due to low air utilization rate and incomplete combustion). Is desired.

On the other hand, there is known a direct injection type diesel engine having a multi-injection nozzle having a plurality of injection holes in a circumferential direction at a tip end. In this type, the fuel is injected from the multi-hole injection nozzle toward the inner peripheral wall of the concave combustion chamber formed at the top of the piston so as to collide with the fuel. The sprays sprayed from each other overlap with each other, and the fuel becomes rich in the polymerized portion, so that the combustibility deteriorates and black smoke (smoke) may be generated, which is a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and attenuates swirl to prevent overlapping of sprays sprayed from a multi-hole spray nozzle, thereby preventing black smoke ( It is an object of the present invention to provide an intake device for a direct-injection diesel engine that can suppress smoke. The present invention further suppresses the generation of black smoke (smoke) by promoting the mixing of fuel and air in a high-load low-speed region, which is a supercharging region, and secures a required intake charge amount in a high-load high-speed region. It is another object of the present invention to provide a direct-injection diesel engine intake device having improved idle stability in a low-load and low-speed range.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a multi-hole combustion injection system having a plurality of injection holes in a circumferential direction at a tip end thereof and injecting fuel from the plurality of injection holes. A swirl generation port for generating a swirl and a swirl generated by the swirl generation port in an intake device of a direct injection diesel engine that includes a nozzle and a supercharger and increases a fuel injection amount according to a supercharging pressure. A swirl damping port for reducing pressure, a generation port on-off valve provided on the swirl generation port, a damping port on-off valve provided on the swirl attenuation port, and control means for opening and closing these generation port on-off valve and the damping port on-off valve This control means opens the production port on-off valve and closes the damping port on-off valve in the high-load low-rotation range, which is the supercharging region, and controls the high-load high In rolling zone and the product port on-off valve and the damping port on-off valve is opened, further, in the low load and low rotational speed range is characterized by a production port on-off valve is closed and the damping port on-off valve opens.

[0008] In the present invention thus configured,
A high swirl is formed by opening the generation port on-off valve and closing the damping port on-off valve in a high-load low-speed region, which is a supercharging region, and forming and opening and closing the generation port in a high-load, high-speed region, which is a supercharging region. A medium swirl is formed by opening the valve and the damping port on-off valve, and a low swirl is formed by closing the generation port on-off valve and opening the damping port on-off valve in a low-load low-speed range. I am trying to do it. Therefore, according to the present invention, in the high-load low-speed range, which is the supercharging region, the mixing of fuel and air is promoted by the high swirl to suppress the generation of black smoke (smoke), and the high-load, high-speed rotation, which is the supercharging region. In the range, the required intake charge can be secured by the medium swirl, the overlap of the spray generated by the over swirl can be prevented, and in the low load and low speed range, the fire is not extinguished by the low swirl so that the idle is stable Can be enhanced.

[0009]

[0010]

[0011]

[0012]

An embodiment of the present invention will be described below with reference to the drawings. 1 is an overall configuration diagram showing an intake device of a direct injection type diesel engine, FIG. 2 is a longitudinal sectional view showing an engine to which an embodiment of the present invention is applied, and FIG. 3 is a plan view showing intake ports and exhaust ports of FIG. FIG.

As shown in FIG. 1, the engine 1 has four cylinders 2 and each cylinder 2 has two intake valves and two exhaust valves. 3 is an intake passage, and 4 is an exhaust passage. Reference numeral 5 denotes a supercharged turbocharger. The supercharged turbocharger 5 includes a compressor 6 arranged in the intake passage 3 and a turbine 7 arranged in the exhaust passage 4.

As shown in FIG. 2, the engine 1 includes a cylinder head 12 corresponding to an opening of a cylinder 2 and a center line CL of the cylinder in a direction perpendicular to the cylinder row arrangement direction.
With reference to FIG. 3, two intake ports (a first intake port 21 and a second intake port 22) are arranged on one side, and exhaust ports 31 and 32 are arranged adjacently on the other side. I have. That is, the opening positions of the intake ports 21 and 22 and the exhaust ports 31 and 32 to the cylinder 2 are arranged substantially symmetrically with respect to a center line CL orthogonal to the cylinder row arrangement direction.

A recess is formed at the center of the top of the piston 16 inserted into the cylinder 2. When the piston 16 is located near the top dead center, the combustion chamber 15 is formed by the recess and the lower surface of the cylinder head 12. Has formed. Intake port 21,
Numeral 22 is independently connected to one side surface of the cylinder head 12 orthogonal to the cylinder row arrangement direction via port passages 21A and 22A, respectively.
The side surface of the cylinder head 12 opposite to the side where the intake ports 21 and 22 communicate is communicated via port passages 31A and 32A.

The intake ports 21 and 22 are connected to the port passage 21.
The first intake port 21 on the side close to the side surface of the cylinder head 12 communicated by A and 22A is a helical port in which an opening (port portion 21B) to the cylinder 2 side is formed in a spiral shape. The opening portion (port portion 21B) of the intake port 22 to the cylinder 2 side is formed not in a spiral shape but in a smooth curve, and the port passage 22A is formed.
Are arranged in the tangential direction of an arc centered on the cylinder center at the opening so as to generate a weak swirl flow along the inner peripheral surface of the cylinder 2 in the same direction as the swirl rotation direction generated by the first intake port 21. Have been. Further, the port passage 22A of the second intake port 22 is formed so as to be substantially horizontal as a positional relationship overlapping the port portion 21B of the first intake port 21 and substantially perpendicularly extends from the port passage 22A via the port portion 22B. It is formed so that it may open. With the overlapping arrangement of the port passages 21A and 22A, the port passages 21A and 22A can be compactly arranged.

As described above, due to the shape and arrangement of the intake ports 21 and 22, the intake air from the first intake port 21 is supplied to the spiral port portion 21B at 21S in FIG.
A swirl having a small radius as shown in FIG.
Although the port 22B is not spiral, the arrangement of the port passage 22A causes a weak swirl having a large radius along the inner peripheral surface of the cylinder head 11 indicated by 22S in FIG. And a tumble flow which is a vertical swirling flow of the cylinder 2 to flow into the cylinder via the substantially vertical port portion 22B. By generating the tumble flow, the second intake port 22 functions as a swirl attenuation port. As a result, the strongest swirl (high swirl) is generated when the intake is performed by the first intake port 21 alone, and when the intake is performed simultaneously from both the intake ports 21 and 22, the second intake port 22 is generated. The swirl flow generated by the first intake port 21 is weakened by the tumble flow generated by, and a medium swirl (medium swirl) is generated. In addition, when the intake is performed by the second intake port 22 alone, the weakest swirl (low swirl) is generated.

The port 21 of each of the intake ports 21 and 22
Poppet valves 61 and 62, which are opening / closing valves for opening and closing the intake ports 21 and 22, respectively, are disposed in the openings of the cylinders B and 22B to the cylinder 2. The poppet valves 61 and 62 are push rods. The rocker arm 13 is pressed by a rocker arm 14 that is oscillated in synchronization with the rotation of the crankshaft of the engine 1 to open and close the intake ports 21 and 22.

Cylinder head 1 of intake ports 21 and 22
2 are connected to respective manifold passages 71, 72 of an intake manifold 70A that is formed integrally with the surge tank 70 by branching from the surge tank 70. The manifold passages 71, 72 are respectively opened and closed in the respective manifold passages 71, 72. Possible on-off valves 81, 82 are provided. These on-off valves 81, 82 are respectively connected to diaphragms 83, 83 as actuators, and these diaphragms 83, 83 are connected to a solenoid valve 8 from a vacuum pump 84, which is rotationally driven by an engine crankshaft.
The negative pressure is supplied via negative pressure supply passages 86, 86 having 5, 85. The on / off valves 81, 82 are opened / closed by the presence / absence of negative pressure supply to the diaphragms 83, 83 by the on / off operation of the solenoid valves 85, 85.

The driving of the solenoid valves 85, 85 is controlled by a control device 90 as a control means. Therefore, each of the on-off valves 81, 82 is controlled to be opened and closed by the control device 90. On the other hand, at a position corresponding to the center of the cylinder 2 of the cylinder head 12, that is, the center of the combustion chamber 15, a unit injector 91 which is a pressure accumulating injector having a pressure accumulating tank moves its injection nozzle 91A into the cylinder 2 (combustion chamber 15). The unit injector 91 is supplied with high-pressure fuel from a fuel injection pump 92. Here, the injection nozzle 91A is a multi-injection hole injection nozzle having a plurality of injection holes formed in the circumferential direction at the tip end, and fuel collides from the multi-injection hole injection nozzle toward the inner peripheral wall of the combustion chamber 15. (See FIG. 4).

Fuel injection pump 92
Is for distributing and pumping a predetermined amount of fuel to each cylinder in accordance with a load, includes a rotating member connected so as to rotate synchronously with a crankshaft (not shown) of the engine 1, and has an accelerator pedal. Operated by the AP through a governor (not shown). That is, the fuel injection pump 92 controls the rotation of the engine 1 (the rotation of the crankshaft).
The fuel is pressurized and timely distributed to each cylinder by a rotating member that rotates synchronously with the cylinder, and the injection amount is adjusted using the operation amount of the accelerator pedal AP as load information.

A pressure sensor 93 detects the intake pressure in the surge tank 70. When the intake pressure detected by the pressure sensor 93 is equal to or higher than the atmospheric pressure, it is a state in which the supercharged turbocharger 5 is operating, that is, a supercharging region. The control device 90 receives information on the number of revolutions of the engine 1, information on the operation amount of the accelerator pedal AP from the fuel injection pump 92, and information on the pressure sensor 9.
3, information on the operation of the supercharged turbocharger 5 is obtained, and based on the information, the intake ports 21 and
The on / off valves 81, 82 provided in the manifold passages 71, 72 connected to the control valve 2 are controlled to open and close. That is, the fuel injection pump 92 also serves as an engine load detecting unit and an engine speed detecting unit, and the pressure sensor 93 serves as a supercharging region determining unit.

FIG. 4 is a plan view showing the behavior of fuel spray when fuel is injected from the injection nozzle toward the inner peripheral wall of the combustion chamber. As shown in FIG. 4, fuel is injected from the injection nozzle 91A, which is a multi-injection nozzle, toward the inner peripheral wall of the combustion chamber 15. At this time, if the swirl is too strong and overswirl, a part of the sprays 100 injected from the adjacent injection holes overlap with each other, and the fuel becomes rich in the overlapping portion 101, so that the fuel property deteriorates and the black smoke (Smoke) occurs. In the present invention, the on-off control of the on-off valves 81 and 82 is performed by the following embodiment to prevent the overlap of the sprays injected from the adjacent injection holes.

Next, with reference to FIG. 5, the contents of control of opening and closing the on-off valves 81 and 82 according to the embodiment of the present invention will be described. FIG.
FIG. 4 is a diagram showing control contents of an on-off valve in each operation range indicated by an engine load and an engine speed according to one embodiment of the present invention. First, when fuel is injected from the injection nozzle 91A, which is a multi-hole injection nozzle, toward the inner peripheral wall of the combustion chamber 15, it is determined whether a part of the sprays 100 injected from the adjacent injection holes overlap each other. Is determined by the following conditions. That is, in the present embodiment, the supercharging region information based on whether the intake pressure in the surge tank 70 detected by the pressure sensor 93 is equal to or higher than the atmospheric pressure (indicated by a in FIG. 5), and the fuel injection Based on the engine speed information from the pump 92, it is determined that the supercharged region and the high engine speed region, that is, the high load high speed region, are in the superimposed state of the spray by the multi-hole injection nozzle.

As described above, in the high-load, high-rotation region, that is, in the operation region in which it is determined that the spray is superimposed by the multi-injection nozzles, in this embodiment, the manifold passage 71 reaching the first intake port 21 is used. The on-off valve 81 provided on the manifold passage 72 and the on-off valve 82 provided on the manifold passage 72 leading to the second intake port 22 are both opened. In this case, the first intake port 21 functions as a swirl generation port, the second intake port 22 functions as a swirl attenuation port, and these ports 21 and 22 function together. A weaker swirl is produced than inhaling at. The generation of swirl in this,
The occurrence of the overlapping of the sprays caused by the occurrence of the overswirl described above is prevented, and as a result, the fuel property is improved and the generation of black smoke (smoke) is requested.

In the other operation regions, that is, the low load region and the high load low rotation region, a part of the spray injected from the adjacent injection holes of the multiple injection hole injection nozzle does not overlap with each other. Therefore, the on-off valve 81 provided in the manifold passage 71 leading to the first intake port 21 is opened, and the on-off valve 82 provided in the manifold passage 72 leading to the second intake port 22 is closed.

As described above, in the low load region and the high load low rotation region, the manifold passage 7 reaching the first intake port 21 is provided.
Since only the on-off valve 81 provided in the valve 1 is opened, a high swirl is generated, and the high swirl promotes mixing of fuel and air, thereby improving combustion efficiency (air utilization rate).
Next, another embodiment of the present invention will be described with reference to FIG. FIG. 6 is a diagram showing control contents of an on-off valve in each operation range indicated by an engine load and an engine speed according to another embodiment of the present invention.

In this embodiment, in a high-load low-speed range (A), which is a supercharging range, the on-off valve 81 provided in the manifold passage 71 leading to the first intake port 21 is opened and the second intake port is opened. A high swirl is generated by closing the on-off valve 82 provided in the manifold passage 72 leading to 22. In the high-load high-speed region, which is a supercharging region, and in the middle-load region, and the low-load high-speed region (B), which are non-supercharging regions, the manifold passages 71, 7 reaching both the intake ports 21, 22
By opening both of the on-off valves 81 and 82 provided in 2, the medium swirl is generated. Further, in the low-load low-speed range (C), the on-off valve 81 provided in the manifold passage 71 leading to the first intake port 21 is closed and the on-off valve provided in the manifold passage 72 leading to the second intake port 22. Opening 82 creates a low swirl.

Generally, in the supercharging region, the fuel injection amount is increased due to a high load, and the swirl tends to be increased because the intake flow velocity is increased. In the low engine speed region, the swirl tends to be weakened because the sliding speed of the piston is slow, while in the high engine speed region, the swirl tends to be increased because the sliding speed of the piston is fast. For this reason, in the high-load, low-speed range (A), which is a supercharging region, a strong swirl is generated by opening only the on-off valve 81 provided in the manifold passage 71 leading to the first intake port 21, and the injection is performed. The mixture of a large amount of fuel and air can be promoted, and the generation of black smoke (smoke) can be suppressed. Further, even in the high swirl region, since the rotation speed is in the low rotation region, the overlapping of the sprays by the multi-injection nozzle does not occur.
Further, since the high-load low-speed range (A) is a low-speed range, the opening time of the intake valve is prolonged, and the required intake charge amount can be secured only by opening one intake port.

In the high-load, high-speed range (B), which is a supercharging range, the opening time of the intake valve is shortened, contrary to the high-load, low-speed range, so it is necessary to open only one intake port. It is not possible to secure a sufficient intake charge. Therefore, in the present embodiment, the manifold passages 71 and 7 reaching both the intake ports 21 and 22 are provided.
By opening both of the on-off valves 81 and 82 provided at 2, the required amount of intake air is ensured. Further, since the intake port 22 functions as a swirl damping port, medium swirl is generated, and overlapping of sprays caused by the multi-injection nozzle generated by overswirl can be prevented. Thereby, mixing of fuel and air is promoted, combustion efficiency (air utilization rate) is increased, output can be increased, and generation of black smoke (smoke) can be suppressed.

In the medium load range and the low load high speed range (B),
As described above, by opening both the on-off valves 81 and 82 provided in the manifold passages 71 and 72 leading to both the intake ports 21 and 22, medium swirl is generated.
In this operating range, the mixing of the fuel and the intake air is promoted by such an appropriate swirl, and the combustion temperature is prevented from increasing due to the improvement of the combustibility, whereby the generation of nitrogen oxides can be suppressed.

Further, in the low-load low-speed range (C), as described above, the on-off valve 81 provided in the manifold passage 71 leading to the first intake port 21 is closed and the manifold reaching the second intake port 22 is closed. By opening the on-off valve 82 provided in the passage 72, a low swirl is generated. That is, the low-load low-speed range (C) is an idling operation range. In this operation range, since the fuel injection amount is small, if the swirl is strong, the fire is extinguished and the idle stability is impaired. . Therefore, in the present embodiment, the idle stability is enhanced in the low-load low-speed range (C) by generating a lower swirl than in the low-load high-speed range.

In the above embodiment, the intake port 21 is provided as a swirl generation port, and the intake port 22 is provided as a swirl attenuation port, and is arranged as shown in FIG. 3. However, in the present invention, as described below. Other intake port arrangements can be employed for the swirl generation port and the swirl attenuation port. FIG. 7 is a plan view showing another arrangement of the intake port and the exhaust port according to the present invention. As shown in FIG. 7, the intake ports 121 and 122 are disposed on one side surface orthogonal to the cylinder row arrangement direction of the cylinder head, and the exhaust ports 31 and 32 are disposed on the side surface opposite to the intake ports 121 and 122. Have been. Each intake port 121,
Numeral 122 is formed as a spiral helical port, and the intake air from the intake port 121 generates a relatively strong swirl indicated by 121S in FIG.
Intake from 2 produces a relatively weak swirl, indicated by 122S in FIG. In addition, swirls generated by the respective intake ports 121 and 122 have the same turning direction and different turning centers. Therefore, when air is simultaneously suctioned from both the intake ports 121 and 122, the swirls interfere with each other and cancel each other. The swirl is weaker than the swirl when the port 122 alone sucks air. As a result, in this embodiment, the intake port 121 functions as a swirl generation port, and the intake port 122 functions as a swirl attenuation port. In addition, the intake port 12
A single swirl forms a high swirl, a middle swirl forms when the intake port 122 alone takes in, and a low swirl forms when a simultaneous intake is performed from both the intake ports 121 and 122.

FIG. 8 is a plan view showing another arrangement of the intake port and the exhaust port according to the present invention. As shown in FIG. 7, the intake ports 221 and 222 are arranged on one side surface parallel to the cylinder row arrangement direction of the cylinder head, and the exhaust ports 231 and 232 are arranged on the intake ports 221 and 22.
2 is disposed on the side opposite to the side. Each intake port 22
1 and 222 are both formed as straight ports. Since the opening of intake port 221 is provided at a position a away from center line CL orthogonal to the cylinder row arrangement direction, a relatively strong swirl indicated by 221S in FIG. Is the center line CL
Since the opening is provided at a position separated by b (a> b) from the distance, a relatively weak swirl indicated by 222S in FIG. 8 is generated. Since the intake ports 221 and 222 are arranged as described above, when the intake is performed simultaneously from both the intake ports 221 and 222, the swirl interferes and cancels out. As a result, the swirl when the intake is performed by the intake port 222 alone is smaller than the swirl. The swirl is weaker. As a result, in this embodiment, the intake port 22
1 functions as a swirl generation port, and the intake port 22
2 functions as a swirl attenuation port. In addition, a high swirl is formed when intake is performed by the intake port 221 alone,
A medium swirl is formed when intake is performed by the intake port 222 alone, and a low swirl is formed when intake is performed simultaneously from both intake ports 221 and 222.

The fuel injection pump 92 is a mechanical pump that increases its discharge pressure in accordance with the rotation speed of the engine 10. Therefore, in the high-load low-speed range, the discharge pressure is low, and the atomization of the fuel is deteriorated.
As a result, black smoke (smoke) increases, but in the embodiment of the present invention, since the high-load low-rotation region is set to the high swirl region, atomization of combustion is achieved, and black smoke (smoke) is reduced.

[0036]

As described above, according to the intake device for a direct injection diesel engine of the present invention, the swirl is attenuated to prevent the sprays sprayed from the multi-hole injection nozzles from overlapping, thereby preventing black smoke ( Smoke) can be suppressed. Further, according to the present invention, the mixing of fuel and air is promoted in the high-load low-rotation region, which is the supercharging region, and the black smoke
Can be suppressed, the required intake air filling amount can be ensured in a high-load, high-speed range, and idle stability can be improved at low-load, low-speed rotation.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram illustrating an intake device of a direct injection diesel engine.

FIG. 2 is a longitudinal sectional view showing an engine to which one embodiment of the present invention is applied.

FIG. 3 is a plan view showing an intake port and an exhaust port of FIG. 2;

FIG. 4 is a plan view showing a behavior of fuel spray when fuel is injected from an injection nozzle toward an inner peripheral wall of a combustion chamber.

FIG. 5 is a diagram showing control contents of an on-off valve in each operation range indicated by an engine load and an engine speed according to an embodiment of the present invention.

FIG. 6 is a diagram showing control contents of an on-off valve in each operation range indicated by an engine load and an engine speed according to another embodiment of the present invention.

FIG. 7 is a plan view showing another arrangement of an intake port and an exhaust port according to the present invention.

FIG. 8 is a plan view showing another arrangement of the intake port and the exhaust port according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Cylinder 5 Highly-charged turbocharger 15 Combustion chamber 16 Piston 21 First intake port 22 Second intake port 81 On-off valve 82 On-off valve 90 Control unit 91 Unit injector 91A Injection nozzle (multi-injection nozzle) 92 Fuel injection Pump 93 Pressure sensor 121 Intake port 122 Intake port 221 Intake port 222 Intake port

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-20925 (JP, A) JP-A-55-57618 (JP, A) Fully open 1987-173524 (JP, U) Really open 1984 130026 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02B 31/02

Claims (1)

(57) [Claims] 1. A multi-injection-hole combustion injection nozzle having a plurality of injection holes in a circumferential direction at a tip end thereof and injecting fuel from the plurality of injection holes, and a supercharger, wherein a fuel is supplied according to a supercharging pressure. A swirl generation port for generating swirl, a swirl attenuation port for weakening swirl generated by the swirl generation port, and a generation port provided in the swirl generation port, in an intake device for a direct injection diesel engine that increases an injection amount. On-off valve
And a damping port opening / closing valve provided in the swirl damping port, and opening / closing of the generation port opening / closing valve and the damping port opening / closing valve.
Control means for operating, and the control means operates in a high-load low-speed range, which is a supercharging range.
Opening the generation port on / off valve and the damping port on / off valve
Is closed and the above generation occurs in the high-load, high-speed
Open the port on-off valve and the damping port on-off valve, and
In addition, in the low-load low-speed range, the generation port on-off valve is closed
An intake device for a direct injection diesel engine, wherein the damping port on-off valve is opened .