Internal combustion engine with pre-chamber

Patent metadata

Field	Value
Publication number	US-11215109-B2
Application number	US-202017130944-A
Country	US
Kind code	B2
Filing date	Dec 22, 2020
Priority date	Feb 12, 2020
Publication date	Jan 4, 2022
Grant date	Jan 4, 2022

Abstract

An internal combustion engine is provided with a pre-chamber provided inside a main combustion chamber. The pre-chamber includes an ignition plug, and a casing provided to a ceiling part to cover the ignition plug, the casing isolating an internal space formed therein from the main combustion chamber. A tumble flow of a mixture gas is formed inside the main combustion chamber. A plurality of communicating holes are formed in the casing, and include a first communicating hole opening to an intake port side and a second communicating hole opening to an exhaust port side. The tumble flow flowing into the pre-chamber through the first communicating hole forms in the pre-chamber a vortex flowing in the opposite direction from the tumble flow. The main combustion chamber is provided with a structure configured to suppress a flow opposing the vortex flowing into the pre-chamber through the second communicating hole.

First claim

What is claimed is:

1. An internal combustion engine with a pre-chamber provided inside a main combustion chamber, the pre-chamber comprising:
an ignition plug attached to a ceiling part of the main combustion chamber and configured to ignite a mixture gas containing a fuel component and air; and
a casing provided to the ceiling part so as to cover the ignition plug, the casing isolating an internal space formed therein from the main combustion chamber,
wherein the main combustion chamber is connected to an intake port and an exhaust port, and intake air flowing into the main combustion chamber through the intake port forms a tumble flow of the mixture gas inside the main combustion chamber,
wherein a plurality of communicating holes communicating the internal space of the casing with the main combustion chamber are formed in the casing, the plurality of communicating holes include a first communicating hole opening to the intake port side in a radial direction of the main combustion chamber, and a second communicating hole opening to the exhaust port side,
wherein the tumble flow flowing into the pre-chamber through the first communicating hole forms in the pre-chamber a vortex flowing in the opposite direction from the tumble flow, and
wherein the main combustion chamber is provided with a structure configured to suppress a flow opposing the vortex inside the pre-chamber flowing into the pre-chamber through the second communicating hole.

2. The internal combustion engine of claim 1 , wherein the structure is a baffle wall provided to an upper surface of a piston forming the main combustion chamber, at a position closer to the exhaust port than the casing, the baffle wall being configured to impede a squish flow flowing to the casing from the exhaust port side.

3. The internal combustion engine of claim 2 , wherein the baffle wall is provided to a flat part formed in a radially center part of the upper surface of the piston so as to protrude upwardly, and the baffle wall overlaps with the first communicating hole and the second communicating hole of the casing in an up-and-down direction, when the piston is located near a compression top dead center.

4. The internal combustion engine of claim 2 , wherein the baffle wall is located on the exhaust port side of the casing, and has a C shape in a plan view.

5. The internal combustion engine of claim 4 , wherein the baffle wall curves so as to be convex on the exhaust port side and curves so as to be concave on the intake port side, and the baffle wall surrounds the periphery of the casing from the exhaust port side, when the piston is located near a compression top dead center.

6. The internal combustion engine of claim 2 ,
wherein the baffle wall has a V shape oriented sideways in a plan view to have two walls, and
wherein ends of the two walls on the exhaust port side are coupled to each other and ends of the two walls on the intake port side are separated from each other to form a given angle therebetween.

7. The internal combustion engine of claim 1 , wherein the structure is a recess formed in an upper surface of a piston forming the main combustion chamber, and at least a part of the casing where the plurality of communicating holes are formed is inserted into the recess, when the piston reaches a top dead center.

8. The internal combustion engine of claim 7 , wherein the recess is provided in an area of the upper surface of the piston on the intake port side from the center of the main combustion chamber in a radial direction, at a position directly below a tip-end part of the casing.

9. The internal combustion engine of claim 8 , wherein, when the piston ascends and reaches a compression top dead center, the tip-end part of the casing is inserted into the recess so that at least a part of the casing where the communicating holes and are formed is inserted in the recess and the tip-end part of the casing is surrounded by an internal surface of the recess.

10. The internal combustion engine of claim 7 , wherein the recess opens to the upper surface of the piston, and an opening of the recess has a circular shape or a substantially circular shape.

11. The internal combustion engine of claim 10 , wherein, when the piston ascends and reaches a compression top dead center, the tip-end part of the casing is inserted into the recess so that at least a part of the casing where the communicating holes and are formed is inserted in the recess and the tip-end part of the casing is surrounded by an internal surface of the recess.

12. The internal combustion engine of claim 1 ,
wherein the structure is a cavity formed in an upper surface of a piston forming the main combustion chamber,
wherein the pre-chamber is located inward of an outer edge of the cavity when seen in an axial direction of the main combustion chamber,
wherein squish areas configured to generate squish flows flowing to the center of the main combustion chamber are provided to the piston, the squish areas being slopes formed so as to surround the periphery of the outer edge, and opposing the ceiling part at a location on the intake port side and a location on the exhaust port side, respectively, and
wherein a radial width of the squish area on the exhaust port side is smaller than a radial width of the squish area on the intake port side.

13. The internal combustion engine of claim 1 ,
wherein the structure is a cavity formed in an upper surface of a piston forming the main combustion chamber,
wherein the pre-chamber is located inward of an outer edge of the cavity when seen in an axial direction of the main combustion chamber,
wherein squish areas configured to generate squish flows flowing to the center of the main combustion chamber are provided to the piston, the squish areas being slopes formed so as to surround the periphery of the outer edge, and opposing the ceiling part at a location on the intake port side and a location on the exhaust port side, respectively, and
wherein the squish area on the exhaust port side is formed by a part of the piston on the exhaust port side in a radial direction of the main combustion chamber being concaved so that a distance between the squish area on the exhaust port side and the ceiling part in the axial direction of the main combustion chamber becomes larger than a distance between the squish area on the intake port side and the ceiling part.

Assignees

• Mazda Motor

Inventors

• Ono Ryohei
• Uchida Kenji
• Harada Yuji

Classifications

• F02B19/1061

  with residual gas chamber, e.g. containing spark plug · CPC title

• F02B19/1019

  with only one pre-combustion chamber (F02B19/1004 take precedence) · CPC title

• F02B19/1014 Primary

  design parameters, e.g. volume, torch passage cross sectional area, length, orientation, or the like · CPC title

• F02B19/08

  the chamber being of air-swirl type · CPC title

• F02B2023/106

  Tumble flow, i.e. the axis of rotation of the main charge flow motion is horizontal · CPC title