Internal combustion engine with common rail pilot and main injection

Patent metadata

Field	Value
Publication number	US-9771860-B2
Application number	US-201514926357-A
Country	US
Kind code	B2
Filing date	Oct 29, 2015
Priority date	Mar 12, 2013
Publication date	Sep 26, 2017
Grant date	Sep 26, 2017

Abstract

An internal combustion engine including a pilot subchamber, a pilot fuel injector having a tip in communication with the pilot subchamber, an ignition element positioned to ignite fuel within the pilot subchamber, and a main fuel injector spaced apart from the pilot fuel injector. The engine includes a common rail in fluid communication with the main fuel injector and with the pilot fuel injector. The internal combustion engine may be a reciprocating engine. A method of combusting fuel in an internal combustion engine is also provided.

First claim

The invention claimed is:

1. An internal combustion engine comprising:
an outer body defining an internal cavity;
a moveable body sealingly and moveably received within the internal cavity to define at least one combustion chamber of variable volume;
a pilot subchamber defined in the outer body in communication with the internal cavity;
a pilot fuel injector having a tip in communication with the pilot subchamber;
an igniter positioned to ignite fuel within the pilot subchamber;
a main fuel injector spaced apart from the pilot fuel injector and having a tip in communication with the internal cavity at a location spaced apart from the pilot subchamber; and
a common rail in fluid communication with the main fuel injector and with the pilot fuel injector.

2. The engine as defined in claim 1 , further comprising a pump in fluid communication with a fuel source and with an inlet of the common rail.

3. The engine as defined in claim 2 , wherein an outlet of the common rail is in selective fluid communication with the fuel source through a metering or pressure regulating valve, one or both of the metering or pressure regulating valve and the pump regulating a fuel pressure within the common rail.

4. The engine as defined in claim 3 , wherein the metering or pressure regulating valve and the pump are actuable by an engine control unit.

5. The engine as defined in claim 1 , wherein the moveable body is a reciprocating piston moveable within the internal cavity.

6. The engine as defined in claim 1 , wherein the internal cavity is defined by two axially spaced apart end walls and a peripheral wall extending between the end walls, the internal cavity having an epitrochoid shape with two lobes, and the moveable body is a rotor body rotatable within the internal cavity in sealing engagement with the peripheral and end walls, the rotor body having three circumferentially spaced apex portions the at least one combustion chamber including three rotating chambers of variable volume, the rotor body being engaged to an eccentric portion of a shaft to rotate and perform orbital revolutions within the cavity with each of the apex portions remaining in sealing engagement with the peripheral wall and separating the three rotating chambers.

7. The engine as defined in claim 1 , wherein the pilot injector and the main injector have tip openings through which the fuel is injected, and an open area defined by the tip openings of the pilot injector is smaller than that defined by the tip openings of the main injector.

8. The engine as defined in claim 1 , wherein the engine includes at least one additional moveable body sealingly and rotationally received within a respective additional internal cavity of the outer body to define a respective additional combustion chamber of variable volume, and further including, for each additional moveable body, a respective additional pilot subchamber defined in the outer body in communication with the respective additional internal cavity, an additional pilot fuel injector having a tip in communication with the respective additional pilot subchamber, an additional igniter positioned to ignite fuel within the respective additional pilot subchamber, and an additional main fuel injector having a tip in communication with the respective additional internal cavity at a location spaced apart from the respective additional pilot subchamber, the common rail also being in fluid communication with the additional main fuel injector and with the additional pilot fuel injector of each additional moveable body.

9. An internal combustion engine comprising:
an outer body defining internal cavities;
for each of the internal cavities:
a respective reciprocating piston sealingly and moveably received within the internal cavity and defining a respective combustion chamber of variable volume therein,
a respective pilot subchamber defined in the outer body in fluid communication with the internal cavity,
a respective pilot fuel injector having a tip in communication with the respective pilot subchamber,
a respective igniter positioned to ignite fuel within the respective pilot subchamber, and
a respective main fuel injector spaced apart from the respective pilot fuel injector, the respective main fuel injector having a tip in communication with the internal cavity at a location spaced apart from the respective pilot subchamber; and

a common rail in fluid communication with each main fuel injector and with each pilot fuel injector.

10. The engine as defined in claim 9 , further comprising a pump in fluid communication with a fuel source and with an inlet of the common rail.

11. The engine as defined in claim 10 , wherein an outlet of the common rail is in selective fluid communication with the fuel source through a metering or pressure regulating valve, one or both of the metering or pressure regulating valve and the pump regulating the fuel pressure within the common rail.

12. The engine as defined in claim 11 , wherein the metering or pressure regulating valve and the pump are actuable by an engine control unit.

13. The engine as defined in claim 9 , wherein the pilot injector and the main injector have tip openings through which the fuel is injected, and an open area defined by the tip openings of the pilot injector is smaller than that defined by the tip openings of the main injector.

14. A method of combusting fuel in an internal combustion engine having a plurality of reciprocating pistons each received in a respective internal cavity defining a respective combustion chamber of variable volume, the method comprising:
pressurizing the fuel in a common rail; and
for each respective internal cavity:
feeding a respective pilot injector with the common rail to inject fuel in a respective pilot subchamber,
igniting the fuel within the respective pilot subchamber,
circulating the ignited fuel out of the respective pilot subchamber and into the respective combustion chamber, and
feeding a respective main injector separate from the respective pilot injector with the common rail to inject fuel into the respective combustion chamber spaced apart from the respective pilot subchamber and pilot injector.

15. The method as defined in claim 14 , wherein the fuel is heavy fuel.

16. The method as defined in claim 14 , wherein pressurizing the fuel in the common rail includes regulating a fuel pressure in the common rail with a pump in fluid communication with an inlet of the common rail.

17. The method as defined in claim 16 , wherein further comprising controlling the pump with an engine control unit.

18. The method as defined in claim 14 , wherein pressurizing the fuel in the common rail includes regulating a fuel pressure in the common rail with a metering or pressure regulating valve in fluid communication with an outlet of the common rail.

19. The method as defined in claim 18 , wherein further comprising controlling the metering or pressure regulating valve with an engine control unit.

20. The method as defined in claim 14 , wherein injecting the fuel in the respective pilot subchamber and injecting the fuel into the respective combustion chamber are performed at a same fuel pressure.

Assignees

• Pratt & Whitney Canada

Inventors

• Thomassin Jean

Classifications

• Y02T10/125

  Cross-Sectional Technologies · mapped topic

• F02B2275/32

  Miller cycle · CPC title

• F02B19/108

  with fuel injection at least into pre-combustion chamber, i.e. injector mounted directly in the pre-combustion chamber · CPC title

• F02B53/10 Primary

  Fuel supply; Introducing fuel to combustion space · CPC title

• F02D41/3094

  the fuel injection being effected by at least two different injectors, e.g. one in the intake manifold and one in the cylinder · CPC title