Internal combustion engine and operating method therefor

• US 7,597,084 B2
• Filed: 03/30/2007
• Issued: 10/06/2009
• Est. Priority Date: 03/09/2005
• Status: Expired due to Fees

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Vachon, John T., Hergart, Carl-Anders
• Primary Examiner(s): KWON, JOHN
• Application Number:
  US11/731,599
• Publication Number:
  US 20070169741A1
• Time in Patent Office: 921 Days
• Field of Search: 123/294, 123/305, 123/434, 123/429
• US Class Current: 123/294
• CPC Class Codes: F02B 2275/14 Direct injection into combustion chamber
• CPC Class Codes: F02B 23/0621 Squish flow
• CPC Class Codes: F02B 23/0624 Swirl flow
• CPC Class Codes: F02B 23/0642 the depth of the combustion space being much smaller than the diameter of the piston, e.g. the depth being in the order of one tenth of the diameter
• 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 23/0672 Omega-piston bowl, i.e. the combustion space having a central projection pointing towards the cylinder head and the surrounding wall being inclined towards the cylinder center axis the surrounding wall being exactly vertical F02B23/0696
• 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 25/04 Engines having ports both in cylinder head and in cylinder wall near bottom of piston stroke
• CPC Class Codes: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02
• CPC Class Codes: F02M 61/1806 characterised by the arrangement of discharge orifices, e.g. orientation or size
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

The present disclosure provides an engine operating method and high power density internal combustion engine, including an engine housing with a plurality of cylinders. Fuel injectors are provided and disposed at least partially within each cylinder, and configured to inject fuel such as diesel, JP8 or another fuel therein for compression ignition. The engine is configured to burn a quantity of injected fuel to yield at least about 150 horsepower per liter of engine displacement at a smoke output of less than about 0.4 grams, and in some cases less than about 0.75 grams, smoke per horsepower-hour, at a fuel consumption of less than about 250 grams fuel per kilowatt-hour output of the engine.

Claims

1. An internal combustion engine comprising:

an engine housing including a plurality of cylinders each having a piston positioned at least partially therein and each piston having a piston bowl with a reentrancy ratio of at least about 1.15;

1 and an aspect ratio of at least about 3.5;

1 and is movable a stroke distance to increase a pressure of the corresponding cylinder to a pressure sufficient for compression ignition of fuel, wherein a diameter of said cylinders and a length of said stroke distance defines a displacement of said internal combustion engine;

a crankshaft coupled with each of said pistons and rotatable via combustion of fuel in each of said cylinders; and

a plurality of fuel injectors having fixed positions relative to said engine housing and including at least one fuel injector extending into each one of said cylinders and configured to inject a liquid fuel therein at an injection pressure via a plurality of outlet orifices;

wherein said engine is configured to burn a quantity of injected fuel in each of said cylinders to yield at least about 150 horsepower per liter of engine displacement at a smoke output of less than about 0.4 grams smoke per horsepower-hour and a fuel consumption of less than about 250 grams fuel per kilowatt-hour output of said engine.

2. The internal combustion engine of claim 1 wherein said pistons each have a stroke distance less than about 80 millimeters.

3. The internal combustion engine of claim 2 wherein a ratio of the diameter of said cylinders to said stroke distance is in a range of about 1.3:

1 to about 1.6;

1.

4. The internal combustion engine of claim 2 wherein said pistons are configured to rotate said crankshaft at a speed of at least about 5000 revolutions per minute, said internal combustion engine being configured to burn a quantity of injected fuel in each of said cylinders to yield a brake mean effective pressure of at least about 200 pounds per square inch when rotating said crankshaft at a speed of at least about 5000 revolutions per minute.

5. The internal combustion engine of claim 1 further comprising a fuel system that includes a common rail fluidly connected with each of said fuel injectors, wherein the at least one fuel injector extending into each of said cylinders includes a plurality of sets of outlet orifices, each set including at least seven outlet orifices.

6. The internal combustion engine of claim 5 wherein at least a portion of said outlet orifices have a converging taper.

7. The internal combustion engine of claim 5 wherein the at least one fuel injector extending into each of said cylinders includes a first nozzle body wherein a first set of said outlet orifices is disposed and a second nozzle body wherein a second set of said outlet orifices is disposed, and wherein an average minimum cross-sectional flow area of the first set is greater than an average minimum cross-sectional flow area of the second set.

8. The internal combustion engine of claim 1 wherein said engine is configured to burn a quantity of liquid fuel injected into each of said cylinders once every fourth piston stroke to yield between about 175 horsepower and about 200 horsepower per liter of engine displacement at a smoke output of less than about 0.1 grams smoke per horsepower-hour.

9. The internal combustion engine of claim 8 further comprising an intake manifold and a plurality of turbochargers configured to supply compressed air to said intake manifold at a boost pressure ratio of between about 4:

1 and about 7;

1 and a common rail fuel system connecting with each of said injectors and configured to supply said fuel to yield an air to fuel ratio in said engine of at least about 25;

1.

10. The internal combustion engine of claim 9 wherein said plurality of turbochargers includes a first turbocharger and a second turbocharger positioned in parallel, and a high-pressure turbocharger positioned in series with said first and second turbochargers.

11. The engine of claim 1 wherein:

each of said cylinders has a diameter between about 2.5 inches and about 3.5 inches;

each of said pistons is movable a stroke distance within the corresponding cylinder which is less than about 2.5 inches, said pistons being configured to rotate said crankshaft at a speed greater than about 5000 RPM;

each of said fuel injectors has a plurality of outlet orifices having an average minimum cross sectional flow area between about 0.002 square millimeters and about 0.01 square millimeters;

said engine further comprising at least one turbocharger configured to supply air to said engine at a boost pressure ratio of between about 4;

1 and about 7;

1, wherein said engine is configured to burn a quantity of injected fuel to yield at least about 150 horsepower per liter of engine displacement at a smoke output of less than about 0.1 grams smoke per horsepower-hour and fuel consumption of less than about 250 grams fuel per kilowatt-hour output of said engine.

12. The engine of claim 1 wherein:

each of said cylinders has a diameter greater than about 4.5 inches;

each of said pistons is movable a stroke distance within the corresponding cylinder that is less than a diameter of the corresponding cylinder, said pistons being configured to rotate said crankshaft at a speed greater than about 6000 RPM;

the at least one injector extending into each of said cylinders includes a first set of outlet orifices and a second set of outlet orifices, wherein the second set has an average minimum cross sectional flow area less than that of the first set;

said engine further comprising at least one turbocharger configured to supply air to said engine at a boost pressure ratio of between about 5;

1 and about 7;

1, and wherein said engine is configured to burn a quantity of injected fuel to yield at least about 200 horsepower per liter of engine displacement at a smoke output of less than about 0.75 grams smoke per horsepower-hour and a fuel consumption of less than about 250 grams fuel per kilowatt-hour output of said engine.

13. A method of operating an internal combustion engine comprising the steps of:

rotating an engine crankshaft via a plurality of pistons each reciprocable a stroke distance within an engine cylinder and configured to increase a pressure within the cylinders to a pressure sufficient for compression ignition of fuel;

supplying pressurized air to the engine cylinders via at least one turbocharger at a boost pressure ratio of between about 4;

1 and about 7;

1;

injecting a liquid fuel into each of the cylinders via fuel injectors extending into each of the cylinders and having a plurality of outlet orifices; and

burning fuel injected into each of the cylinders to yield at least about 150 horsepower per liter of engine displacement at a smoke output of less than about 0.4 grams smoke per horsepower-hour and a fuel consumption of less than about 250 grams fuel per kilowatt-hour output of the engine.

14. The method of claim 13 wherein the step of rotating an engine crankshaft comprises rotating the engine crankshaft at a speed of at least about 5000 revolutions per minute, and wherein the step of burning fuel further comprises burning fuel to yield a brake mean effective pressure of at least about 200 pounds per square inch in each of the cylinders.

15. The method of claim 14 wherein the step of injecting fuel comprises injecting fuel at a pressure of at least about 150 MPa via at least seven outlet orifices in each of the fuel injectors.

16. The method of claim 15 wherein the rotating step comprises rotating the engine crankshaft at a speed greater than about 6000 revolutions per minute, and wherein the burning step further comprises burning fuel injected once every fourth piston stroke to yield a brake mean effective pressure of at least about 300 pounds per square inch in each of the cylinders.

17. The method of claim 16 wherein the burning step further comprises burning fuel to yield between about 175 horsepower per liter of engine displacement and about 200 horsepower per liter of engine displacement at a smoke output of less than about 0.1 grams smoke per horsepower-hour.