INTERNAL COMBUSTION ENGINE

• US 20180216592A1
• Filed: 01/29/2018
• Published: 08/02/2018
• Est. Priority Date: 01/30/2017
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: SAKAI, Hiroyuki
• Granted Patent: US 10,247,156 B2
• Time in Patent Office: Days
• CPC Class Codes: F02B 11/00 Engines characterised by both fuel-air mixture compression and air compression, or characterised by both positive ignition and compression ignition, e.g. in different cylinders
• CPC Class Codes: F02B 17/005 having direct injection in the combustion chamber
• CPC Class Codes: F02B 2023/108 Swirl flow, i.e. the axis of rotation of the main charge flow motion is vertical
• CPC Class Codes: F02B 23/0636 the combustion space having a substantially flat and horizontal bottom
• CPC Class Codes: F02B 23/0651 the fuel spray impinging on reflecting surfaces or being specially guided throughout the combustion space
• CPC Class Codes: F02B 23/0669 having multiple fuel spray jets per injector nozzle
• CPC Class Codes: F02B 23/0678 Unconventional, complex or non-rotationally symmetrical shapes of the combustion space, e.g. flower like, having special shapes related to the orientation of the fuel spray jets
• CPC Class Codes: F02B 23/101 the injector being placed on or close to the cylinder centre axis, e.g. with mixture formation using spray guided concepts
• CPC Class Codes: F02B 31/08 having multiple air inlets
• CPC Class Codes: F02B 31/085 having two inlet valves
• CPC Class Codes: F02D 2041/0015 for engines with means for controlling swirl or tumble flow, e.g. by using swirl valves
• CPC Class Codes: F02D 41/3041 with means for triggering compression ignition, e.g. spark plug
• CPC Class Codes: F02D 41/3047 said means being a secondary injection of fuel
• CPC Class Codes: F02D 41/402 Multiple injections
• CPC Class Codes: F02M 2200/09 Fuel-injection apparatus having means for reducing noise
• CPC Class Codes: F02M 2200/242 Displacement sensors
• CPC Class Codes: F02M 2200/247 Pressure sensors
• CPC Class Codes: F02M 2200/248 Temperature sensors
• CPC Class Codes: F02M 61/162 Means to impart a whirling motion to fuel upstream or near discharging orifices
• CPC Class Codes: F02M 67/12 having valves
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies
• CPC Class Codes: Y02T 10/30 : Use of alternative fuels, e.g. biofuels

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.

Claims

1. An internal combustion engine comprising:

a fuel injector arranged at a top surface of a cylinder;

a spark plug for igniting an air-fuel mixture in a combustion chamber;

a piston having a cavity in its top surface;

a swirl control device controlling 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 arranged so as to be positioned in said cavity when viewed in an axial direction of said cylinder;

said cavity is formed so as to change in distance from said fuel injector to a side wall surface of said cavity, in the circumferential direction;

said control system is configured to be able to perform ignition assist control for successively performing injection of main fuel from said fuel injector and injection of ignition assist fuel, and 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 injection of said ignition assist fuel burn by flame propagation by said spark plug and make the 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 the engine load is relatively high, compared to when the engine load is relatively low, the fuel sprayed from said fuel injector heads toward parts of said side wall surface which are relatively short in distances from said fuel injector.

2. The internal combustion engine according to claim 1, wherein said cavity is formed so that inside projecting parts with relatively short distances from said fuel injector to the side wall surface and outside recessed parts with relatively long distances from said fuel injector to the side wall surface are 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

spray holes of said fuel injector 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 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

spray holes of said fuel injector 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 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 has 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 a cylinder.

6. The internal combustion engine according to claim 3, wherein said fuel injector has 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 a cylinder.

7. The internal combustion engine according to claim 4, wherein said fuel injector has 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 a cylinder.