Internal combustion engine with pilot and main injection

Patent metadata

Field	Value
Publication number	US-9399947-B2
Application number	US-201313796216-A
Country	US
Kind code	B2
Filing date	Mar 12, 2013
Priority date	Mar 12, 2013
Publication date	Jul 26, 2016
Grant date	Jul 26, 2016

Abstract

An internal combustion engine with at least two rotatable bodies each defining at least one combustion chamber of variable volume and, for each rotatable body: 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 first fuel conduit in fluid communication with each main fuel injector, and a common second fuel conduit in fluid communication with each pilot fuel injector. First and second pressure regulating mechanisms which are settable at different pressure values from one another respectively regulate a fuel pressure in the first and second conduits. 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:
at least two rotatable bodies;
an outer body defining a respective internal cavity for each of the at least two rotatable bodies, each of the at least two rotatable bodies being sealingly and rotationally received within the respective internal cavity to define at least one combustion chamber of variable volume;
the engine including, for each of the at least two rotatable bodies:
a pilot subchamber defined in the outer body in communication with the respective 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, and
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;

a first chamber of a common rail in fluid communication with each main fuel injector;
a second chamber of the common rail in fluid communication with each pilot fuel injector;
a first metering or pressure regulating valve in fluid communication with the first chamber; and
a second metering or pressure regulating valve providing selective fluid communication between the first and second chambers, the first and second metering or pressure regulating valves being settable at different pressure values from one another.

2. The engine as defined in claim 1 , wherein the first metering or pressure regulating valve is provided at least in part in a pump in fluid communication with a fuel source and with an inlet of the first chamber.

3. The engine as defined in claim 2 , further comprising a third metering or pressure regulating valve through which an outlet of the second chamber is in fluid communication with the fuel source.

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

5. The engine as defined in claim 1 , wherein each respective internal cavity is defined by two axially spaced apart end walls and a peripheral wall extending between the end walls, and each of the at least two rotatable bodies includes a rotor rotatable within the respective internal cavity in sealing engagement with the peripheral and end walls.

6. The engine as defined in claim 5 , wherein each respective internal cavity defines an epitrochoid shape with two lobes, each rotor has three circumferentially spaced apex portions, and the at least one combustion chamber include three rotating chambers of variable volume, the rotor being engaged to an eccentric portion of a shaft to rotate and perform orbital revolutions within the respective internal cavity with each of the apex portions remaining in sealing engagement with the peripheral wall and separating the chambers.

7. A rotary internal combustion engine comprising:
an outer body having at least two internal cavities each defined by two axially spaced apart end walls and a peripheral wall extending between the two axially spaced apart end walls;
a rotor body received in each of the at least two internal cavities, each rotor body being rotatable within a respective one of the at least two internal cavities in sealing engagement with the peripheral wall and with the two axially spaced apart end walls and defining at least one chamber of variable volume in the respective one of the at least two internal cavities;
for each of the at least two internal cavities:
a pilot subchamber defined in the outer body in fluid 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, and
a main fuel injector spaced apart from the pilot fuel injector, the main fuel injector having a tip in communication with the internal cavity at a location spaced apart from the pilot subchamber;

a first chamber of a common rail in fluid communication with each main fuel injector;
a second chamber of a common rail in fluid communication with each pilot fuel injector and in selective fluid communication with the first chamber;
a first metering or pressure regulating valve in fluid communication with the first chamber for regulating a fuel pressure therein; and
a second metering or pressure regulating valve in fluid communication with the second chamber for regulating a fuel pressure therein, the first and second metering or pressure regulating valves being settable at different pressure values from one another.

8. The engine as defined in claim 7 , wherein each of the at least two internal cavities defines an epitrochoid shape with two lobes, and each rotor body has three circumferentially spaced apex portions, and the at least one combustion chamber include three rotating chambers of variable volume, each rotor body being engaged to an eccentric portion of a shaft to rotate and perform orbital revolutions within the respective one of the at least two internal cavities with each of the apex portions remaining in sealing engagement with the peripheral wall and separating the chambers.

9. The engine as defined in claim 7 , wherein the first metering pressure regulating valve is provided at least in part in a first pump in fluid communication with a fuel source and an inlet of the first chamber.

10. The engine as defined in claim 7 , wherein the first and second chambers are in selective fluid communication with each other through the second metering or pressure regulating valve.

11. The engine as defined in claim 10 , wherein the first metering or pressure regulating valve is provided at least in part in a pump in fluid communication with a fuel source and with the first chamber, and a fluid communication between an outlet of the second chamber and the fuel source is provided through a third metering or pressure regulating valve.

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

13. A method of combusting fuel in an internal combustion engine having at least two rotatable bodies each defining at least one respective combustion chamber, the method comprising:
pressurizing the fuel in a first chamber of a common rail at a first pressure;
circulating the fuel from the first chamber to a second chamber of the common rail and pressurizing the fuel in the second chamber at a second pressure different from the first pressure; and
for each of the rotatable bodies of the engine:
feeding a respective pilot injector with fuel at the second pressure from the second chamber of 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 one of the at least one respective combustion chamber, and
feeding a respective main injector with fuel at the first pressure from the first chamber of the common rail to inject fuel into the one of the at least one respective combustion chamber spaced apart from the respective subchamber and the respective pilot injector.

14. The method as defined in claim 13 , wherein the fuel is heavy fuel.

15. The method as defined in claim 13 , wherein pressurizing the fuel in the first chamber of the common rail and pressurizing the fuel in the second chamber of the common rail includes regulating the first and second pressures with at least one engine control unit.

16. An internal combustion engine comprising:
an outer body defining at least two internal cavities each se

Assignees

• Pratt & Whitney Canada

Inventors

• Schulz Edwin
• Thomassin Jean

Classifications

• F01C1/22

  of internal-axis type with equidirectional movement of co-operating members at the points of engagement, or with one of the co-operating members being stationary, the inner member having more teeth or tooth- equivalents than the outer member · CPC title

• F02B53/10 Primary

  Fuel supply; Introducing fuel to combustion space · CPC title

• F02B19/108 Primary

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

• F02M55/025

  Common rails · CPC title

• Y02T10/17

  Cross-Sectional Technologies · mapped topic