JPH08232773A - Exhaust gas recirculation device - Google Patents

Abstract

PURPOSE: To reduce incurring of a push out loss through high-efficient discharge of exhaust gas at an exhaust stroke by a method wherein an exhaust gas return port opened to an intake passage and an exhaust gas introduction port opened to a combustion chamber in the top surface position of a piston at the opening period of the exhaust valve of a cylinder block are intercommunicated through a recirculation passage. CONSTITUTION: Since at the exhaust stroke of an internal combustion engine 2, the top surface 12a of a piston 12 is positioned at the opening period of an exhaust valve 30, approximately simultaneously with opening of the exhaust valve 30, a part of exhaust gas in a combustion chamber 8 is pushed out to a recirculation passage 44 through an exhaust gas introduction port 46. The exhaust gas flows through a check valve 50 and a gas storage tank 52 to an EGR adjusting valve 54 and is returned to an intake passage 32 through operation of the EGR adjusting valve 54. When the piston 12 is moved to the top dead center side, the exhaust gas introduction port 46 is closed and exhaust gas is discharged only through an exhaust port 20. In a so formed EGR device, a push-out loss is reduced without increasing a blowout loss so much and the pump loss of an internal combustion engine 2 is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas recirculation system, and more particularly to an exhaust gas recirculation system capable of reducing pump loss of an internal combustion engine.

[0002]

2. Description of the Related Art Some internal combustion engines of vehicles are equipped with an exhaust gas recirculation device for returning a part of exhaust gas as an inert component to an intake system and adding it to air.

In this exhaust gas recirculation device, an EGR adjusting valve is provided in the middle of a recirculation passage for returning exhaust gas from the exhaust system to the intake system, and the EGR adjusting valve is operated and controlled according to the operating state of the internal combustion engine to the intake system. The exhaust gas recirculation amount (EGR amount) is adjusted.

As such an exhaust gas recirculation device, for example, as shown in FIG. 4, an intake pipe 106 having an intake passage 104 for guiding air to the internal combustion engine 102 is provided to guide the exhaust gas of the internal combustion engine 102 to the outside. An exhaust pipe 110 in which the exhaust passage 108 is formed is provided, and the exhaust introduction port 11 is provided in the exhaust passage 108.
2 is provided by opening the exhaust gas recirculation port 114 in the intake passage 104.
An exhaust gas inlet 112 and an exhaust gas recirculation port 114.
Recirculation pipe 1 having a recirculation passage 116 communicating with
18 is provided, an EGR adjusting valve 120 is provided in the middle of the recirculation passage 116, and a control mechanism 122 for controlling the operation of the EGR adjusting valve 120 is provided, whereby a part of exhaust gas is extracted from the exhaust passage 108 and the intake passage is provided. There is something that is returned to 104.

In a two-cycle internal combustion engine, a structure for connecting the exhaust passage and the combustion chamber is disclosed in, for example, Japanese Utility Model Laid-Open No. 59-146543. As shown in FIG. 5, the one disclosed in this publication has a communication passage 2 that connects a combustion chamber 204 of an internal combustion engine 202 with an exhaust passage 206.
08 is provided, and an opening / closing valve 210 made of bimetal or the like is provided in the middle of the communication passage 208, and the opening / closing valve 210 is opened at a low temperature to release the pressure of the combustion chamber 204 to the exhaust passage 206 to facilitate the start. .

[0006]

By the way, in the conventional exhaust gas recirculation device, when part of the exhaust gas is recirculated from the exhaust passage to the combustion chamber, the pump loss (pump loss) in the intake stroke is reduced. However, in the exhaust stroke,
Exhaust gas must be extruded at a high pressure, so that the extruding loss becomes large and the pump loss in the exhaust stroke becomes large, so that the pump loss of the internal combustion engine becomes large.

[0007]

In order to eliminate the above-mentioned inconvenience, therefore, the present invention provides an exhaust gas recirculation port opening to an intake passage for introducing air into an internal combustion engine, and the exhaust gas recirculation port has a recirculation passage. Is provided in communication with one end side of the internal combustion engine, and the cylinder block of the internal combustion engine is provided with an exhaust introduction port that opens to the combustion chamber at the top surface position of the piston at the exhaust valve opening timing. It is characterized in that the other end side is provided so as to communicate with each other.

[0008]

According to the structure of the present invention, in the internal combustion engine, the exhaust gas is discharged from the exhaust port by the opening operation of the exhaust valve in the exhaust stroke, that is, in the process of discharging the exhaust gas after combustion from the combustion chamber to the outside. At the same time, the exhaust gas is discharged from the recirculation passage through the exhaust gas introduction port, so that the exhaust gas can be discharged efficiently. As a result, the extrusion loss can be reduced without increasing the blowout loss, and thus the pump loss of the internal combustion engine can be reduced.

[0009]

Embodiments of the present invention will be described in detail and specifically with reference to the drawings. 1 to 3 show an embodiment of the present invention. In FIG. 1, 2 is an internal combustion engine, 4 is a cylinder block, and 6 is a cylinder head.

The cylinder block 4 is provided with a cylindrical cylinder wall surface 10 that forms the combustion chamber 8, and a piston 12 that reciprocates along the cylinder wall surface 10 is provided.

A combustion chamber head wall surface 14 is formed in the cylinder head 6 so as to form a combustion chamber 8, and the combustion chamber 8 is also formed.
An intake valve seat 18 having an intake port 16 opening to the inside and an exhaust valve seat 22 having an exhaust port 20 are attached, and further, an intake port 24 and an exhaust port 2 communicating with the intake port 16 are provided.
An exhaust port 26 communicating with 0 is formed.

Further, the cylinder head 6 has an intake port 16
Intake valve 28 for opening and closing and exhaust valve 3 for opening and closing exhaust port 20
0 and 0 are provided so as to be reciprocally movable.

Further, the cylinder head 6 has an intake pipe 34 in which an intake passage 32 is formed which communicates with the intake port 24 and guides air to the internal combustion engine 2, and exhaust gas from the internal combustion engine 2 which communicates with the exhaust port 26. And an exhaust pipe 38 in which an exhaust passage 36 for guiding the exhaust gas is formed.

The internal combustion engine 2 is provided with an exhaust gas recirculation device 40 for returning a part of the exhaust gas to the intake passage 32 of the intake system.

In this exhaust gas recirculation device 40, an exhaust gas recirculation port 42 that opens into the intake air passage 32, a recirculation passage 44 whose one end side communicates with this exhaust gas recirculation port 42, and the other end side of this recirculation passageway 44 communicates with each other. As described above, the exhaust gas introduction port 46 opening from the cylinder wall surface 10 to the combustion chamber 8 is provided.

The recirculation passage 44 comprises a pipe side recirculation passage 44a formed in the recirculation pipe 48 and a block side recirculation passage 44b formed in the cylinder block 4.

The exhaust introduction port 46 is formed so as to open from the cylinder wall surface 10 to the combustion chamber 8 at the position of the top surface 12a of the piston 12 when the exhaust valve 30 is opened.

An exhaust gas introduction port 46 is provided in the middle of the recirculation passage 44.
A check valve 50, an air storage tank 52, and an EGR adjustment valve 54 are sequentially provided from the side.

The check valve 50 prevents exhaust gas from flowing back from the air storage tank 52 side to the exhaust gas introduction port 46 side.

The air storage tank 52 has a predetermined volume, and alleviates the pressure fluctuation of the exhaust gas from the combustion chamber 8 side.

The EGR adjusting valve 54 comprises a solenoid 56, a valve element 58 reciprocating by the solenoid 56, and a valve seat 60 on which the valve element 58 comes in and out of contact. The EGR adjustment valve 54 is a control unit 62 for inputting the operating state of the internal combustion engine 2.
The exhaust gas recirculation amount to the intake passage 32 side is adjusted by the operation control.

Next, the operation of this embodiment will be described.

In the internal combustion engine 2, in the exhaust stroke, that is, in the process of exhausting the exhaust gas after the combustion of fuel in the combustion chamber 8 to the outside of the combustion chamber 8, the top surface 12 of the piston 12
Since a is located at the opening timing of the exhaust valve 30, the exhaust valve 3
Almost at the same time when 0 is opened, a part of the exhaust gas in the combustion chamber 8 is extruded from the exhaust gas introduction port 46 into the recirculation passage 44, and this exhaust gas passes through the check valve 50 and the storage tank 52 and then the EGR adjustment valve 54.
The exhaust gas recirculation amount to the intake passage 32 is adjusted by the operation of the EGR adjustment valve 54, and the exhaust gas is recirculated to the intake passage 32.

When the piston 12 moves toward the cylinder head 6 side of the exhaust introduction port 46, that is, when it moves to the top dead center side, the exhaust introduction port 46 is closed and the exhaust gas is discharged only from the exhaust port 20. It

As a result, as shown in FIG. 2, as compared with the conventional case (shown by the solid line in FIG. 2), the extrusion loss is reduced without increasing the blowout loss so much, and as a result, the pump loss of the internal combustion engine 2 is reduced. It can be reduced.

That is, if the extrusion loss is reduced by simply changing the opening timing of the exhaust valve 30, the opening timing of the exhaust valve 30 should be advanced (see the broken line in FIG. 3), or
It is necessary to increase the diameter of the exhaust port 20. However, as shown in FIG. 3, if the opening timing of the exhaust valve 30 is earlier than the normal time (shown by the solid line in FIG. 3) (shown by the broken line in FIG. 3), the blowout loss becomes large, so that the internal combustion engine 2
Pump loss will increase.

However, in the structure of this embodiment, a part of the exhaust gas is exhausted from the exhaust valve 30 without advancing the opening timing of the exhaust valve 30 or increasing the diameter of the exhaust port 20.
Since the gas is recirculated from the recirculation passage 44 to the intake passage 32 almost at the same time as the opening timing of the above, as shown in FIG. 2, the extrusion loss is reduced and the extrusion loss is reduced as compared with the case of FIG. The pump loss of the engine 2 can be reduced.

Further, by providing the check valve 50 in the recirculation passage 44, it is possible to prevent the exhaust gas in the recirculation passage 44 on the side of the storage tank 52 from flowing back to the combustion chamber 8 side.

Furthermore, by providing the storage tank 52 in the recirculation passage 44, it is possible to reduce the pressure fluctuation of the exhaust gas from the combustion chamber 8 side.

[0030]

As is apparent from the above detailed description, according to the present invention, an exhaust gas recirculation port opening to an intake passage for guiding air to an internal combustion engine is provided, and one end side of a recirculation passage is communicated with the exhaust gas recirculation port. The cylinder block of the internal combustion engine is provided with an exhaust gas inlet opening to the combustion chamber at the top surface of the piston when the exhaust valve is open, and the other end of the recirculation passage is connected to the exhaust gas inlet. As a result, in the exhaust stroke, the exhaust loss can be efficiently discharged and the extrusion loss can be reduced without increasing the blowout loss, and thus the pump loss of the internal combustion engine can be reduced.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an exhaust gas recirculation device.

FIG. 2 is an indicator diagram of volume and pressure.

FIG. 3 is an indicator diagram when an exhaust valve is opened earlier.

FIG. 4 is a configuration diagram of a conventional exhaust gas recirculation device.

FIG. 5 is a configuration diagram of a conventional internal combustion engine that connects a combustion chamber and an exhaust passage.

[Explanation of symbols]

 2 Internal Combustion Engine 4 Cylinder Block 6 Cylinder Head 8 Combustion Chamber 12 Piston 28 Intake Valve 30 Exhaust Valve 32 Intake Passage 36 Exhaust Passage 40 Exhaust Recirculation Device 42 Exhaust Recirculation Port 44 Recirculation Passage 46 Exhaust Inlet 50 Check Valve 52 Storage Tank 54 EGR adjustment valve 62 Control unit

Claims (1)

[Claims] 1. An exhaust gas recirculation port opening to an intake passage for introducing air to an internal combustion engine, one end side of a recirculation passage communicating with the exhaust gas recirculation port, and an exhaust valve in a cylinder block of the internal combustion engine. An exhaust gas recirculation device, wherein an exhaust gas inlet opening to the combustion chamber is provided at the top surface position of the piston at the opening time, and the other end side of the recirculation passage is connected to this exhaust gas inlet.