Internal combustion engine

Patent metadata

Field	Value
Publication number	US-10247156-B2
Application number	US-201815882203-A
Country	US
Kind code	B2
Filing date	Jan 29, 2018
Priority date	Jan 30, 2017
Publication date	Apr 2, 2019
Grant date	Apr 2, 2019

Abstract

An internal combustion engine comprises a fuel injector 31 , a spark plug 16 , a piston 14 having a cavity 91 , a swirl control device 95 , and a control system 70 . The cavity is formed so as to change in distance from the fuel injector to a side wall surface of the cavity, in the circumferential direction. The system performs ignition assist control for successively performing injections of main fuel and ignition assist fuel, makes an air-fuel mixture formed by the ignition assist fuel burn by flame propagation by the spark plug, and makes the remaining fuel burn by pre-mix compression self-ignition. The system controls the swirl control device during the ignition assist control so that when the engine load is high, the fuel sprayed heads toward parts of the side wall surface which are short in distances from the fuel injector.

First claim

The invention claimed is:

1. An internal combustion engine comprising:
a fuel injector arranged at a top surface of a cylinder; a spark plug configured to ignite an air-fuel mixture in a combustion chamber; a piston having a cavity in its top surface;
a swirl control device configured to control a strength of a swirl flow formed in said combustion chamber; and
a control system configured to control said fuel injector, said spark plug, and said swirl control device,
wherein
said fuel injector is positioned in said cavity when viewed in an axial direction of said cylinder;
said cavity includes a side wall surface, the side wall surface being spaced apart from said fuel injector by different distances in a circumferential direction;
said control system being configured to perform ignition assist control, the ignition assist control including successively performing an injection of a main fuel from said fuel injector and an injection of an ignition assist fuel, controlling injection amounts and injection timings of said main fuel and said ignition assist fuel and an ignition timing of said spark plug so as to make an air-fuel mixture formed by the injection of said ignition assist fuel burn by flame propagation and make a remaining fuel burn by pre-mix compression self-ignition using heat generated by said combustion by flame propagation; and
said control system is configured to control said swirl control device during said ignition assist control so that when an engine load is relatively high, compared to when the engine load is relatively low, the fuel sprayed from said fuel injector heads toward first parts of said side wall surface of said cavity which are relatively closer to said fuel injector than other parts of said side wall surface of said cavity.

2. The internal combustion engine according to claim 1 , wherein said cavity includes inside projecting parts formed as the first parts, the inside projecting parts having relatively short distances from said fuel injector to said side wall surface and outside recessed parts having relatively long distances from said fuel injector to said side wall surface, the inside projecting parts and the outside recessed parts being alternately arranged in the circumferential direction, and at least two each of said inside projecting parts and said outside recessed parts are provided.

3. The internal combustion engine according to claim 2 , wherein
said fuel injector includes spray holes which are formed so that spray directions from the spray holes are directions toward said outside recessed parts,
said control system is configured to control said swirl control device so that when an engine load is lower than a predetermined load, the swirl flow is relatively weak so as to suppress movement of fuel sprayed from said fuel injector in the circumferential direction, and
said control system is configured to control said swirl control device so that when an engine load is at said predetermined load or more, the swirl flow is relatively strong so as to promote movement of the fuel sprayed from said fuel injector in the circumferential direction.

4. The internal combustion engine according to claim 2 , wherein
said fuel injector includes spray holes which are formed so that the spray directions from the spray holes are directions toward said inside projecting parts,
said control system is configured to control said swirl control device so that when an engine load is lower than a predetermined load, the swirl flow is relatively strong so as to promote movement of the fuel sprayed from said fuel injector in the circumferential direction, and
said control system is configured to control said swirl control device so that when an engine load is at said predetermined load or more, the swirl flow is relatively weak so as to suppress movement of the fuel sprayed from said fuel injector in the circumferential direction.

5. The internal combustion engine according to claim 2 , wherein said fuel injector includes a number of spray holes equal to the number of said inside projecting parts of said cavity, and the spray holes of said fuel injector and said inside projecting parts are arranged at equal intervals in the circumferential direction of the cylinder.

6. The internal combustion engine according to claim 3 , wherein said fuel injector includes a number of spray holes equal to the number of said inside projecting parts of said cavity, and the spray holes of said fuel injector and said inside projecting parts are arranged at equal intervals in the circumferential direction of the cylinder.

7. The internal combustion engine according to claim 4 , wherein said fuel injector includes a number of spray holes equal to the number of said inside projecting parts of said cavity, and the spray holes of said fuel injector and said inside projecting parts are arranged at equal intervals in the circumferential direction of the cylinder.

Assignees

• Toyota Motor Co Ltd

Inventors

• Sakai Hiroyuki

Classifications

• F02D41/402

  Multiple injections · CPC title

• F02D41/3047

  said means being a secondary injection of fuel · CPC title

• F02B2023/108

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

• F02B31/085

  having two inlet valves · CPC title

• F02B31/08

  having multiple air inlets · CPC title