Four cycle four cylinder in-line engine with rotors of a supercharging device used as balance shafts

• US 6,439,188 B1
• Filed: 07/19/2001
• Issued: 08/27/2002
• Est. Priority Date: 07/19/2001
• Status: Expired due to Fees

• Current Assignee: Brunswick Corporation
• Original Assignee: Brunswick Corporation
• Inventors: Davis, Richard A.
• Primary Examiner(s): NGUYEN, HOANG M
• Application Number:
  US09/909,113
• Time in Patent Office: 404 Days
• Field of Search: 606/051, 123/192.2
• US Class Current: 123/193.2
• CPC Class Codes: F02B 2075/027 four
• CPC Class Codes: F02B 2075/1816 four
• CPC Class Codes: F02B 61/045 for marine engines
• CPC Class Codes: F02B 67/04 of mechanically-driven auxiliary apparatus
• CPC Class Codes: F02B 75/20 with cylinders all in one line
• CPC Class Codes: F16F 15/265 Arrangement of two or more balancer shafts F16F15/267 takes precedence

Abstract

A four cycle four cylinder in-line internal combustion engine is provided with a housing structure that contains two shafts which rotate in opposite directions to each other and at the same rotational velocity. Pairs of counterweights are attached to the two shafts in order to provide a counterbalance force which is generally equal to an opposite from the secondary shaking force which results from the reciprocal movement of the pistons of the engine. The first and second shafts are rotors of a supercharging device, such as a Roots blower. The rotational speed of the first and second shafts is twice that of the rotational speed of the crankshaft of the engine and the provision of counterweights on the first and second shafts balances the secondary forces caused by the reciprocal motion of the piston in the engine.

Claims

1. An engine, comprising:

a crankshaft supported for rotation about a crankshaft axis;

a plurality of pistons connected to said crankshaft, each of said plurality of pistons being disposed for reciprocating movement within an associated one of a plurality of cylinders of said engine;

a first shaft supported for rotation about a first axis of rotation at a first rotational velocity in a first rotational direction, said first shaft having a first center of gravity which is radially displaced from said first axis of rotation by a first preselected amount;

a second shaft supported for rotation about a second axis of rotation at a second rotational velocity in a second rotational direction, said second shaft having a second center of gravity which is radially displaced from said second axis of rotation by a second preselected amount, said first and second axes of rotation being generally parallel to said crankshaft axis, said first and second rotational directions being opposite to each other, said first and second rotational velocities each being generally equal to a preselected multiple of the rotational velocity of said crankshaft; and

a housing structure attached to said engine, said first and second shafts being supported by said housing structure for rotation within said housing structure, said housing structure being removably attached to said engine, said housing structure containing a supercharging device.

2. The engine of claim 1, wherein:

said first and second shafts are first and second rotors, respectively, of said supercharging device.

3. The engine of claim 2, wherein:

said supercharging device is a Roots blower.

4. The engine of claim 1, wherein:

a first plane, bisecting each of said plurality of pistons and containing said vertical axis, extends between and is equidistant from said first and second axes of rotation.

5. The engine of claim 4, wherein:

said engine is a powerhead of an outboard motor.

6. The engine of claim 1, further comprising:

a first counterweight attached to said first shaft to cause said first center of gravity to be radially displaced from said first axis of rotation by said first preselected amount; and

a second counterweight attached to said second shaft to cause said second center of gravity to be radially displaced from said second axis of rotation by said second preselected amount.

7. The engine of claim 6, wherein:

said first counterweight is formed as an integral part of said first shaft and said second counterweight is formed as an integral part of said second shaft.

8. The engine of claim 1, wherein:

said preselected multiple is two.

9. The engine of claim 1, wherein:

said plurality of pistons comprises four pistons connected to said crankshaft and said plurality of cylinders comprises four cylinders.

10. The engine of claim 9, wherein:

said four cylinders are disposed in an in-line configuration.

11. The engine of claim 1, wherein:

said engine is a four cycle engine.

12. The engine of claim 1, wherein:

said engine is a marine engine.

13. The engine of claim 1, wherein:

said first and second shafts are connected in torque transmitting association with said crankshaft.

14. The engine of claim 1, wherein:

said first shaft is connected in torque transmitting association with said crankshaft and said second shaft is connected in torque transmitting association with said first shaft.

15. An engine of an outboard motor, comprising:

a crankshaft supported for rotation about a vertical axis;

a plurality of pistons connected to said crankshaft, each of said plurality of pistons being disposed for reciprocating movement within an associated one of a plurality of cylinders of said engine;

a first shaft supported for rotation about a first axis of rotation at a first rotational velocity in a first rotational direction, said first shaft having a first center of gravity which is radially displaced from said first axis of rotation by a first preselected amount; and

a second shaft supported for rotation about a second axis of rotation at a second rotational velocity in a second rotational direction, said second shaft having a second center of gravity which is radially displaced from said second axis of rotation by a second preselected amount, said first and second axes of rotation being generally parallel to said vertical axis, said first and second rotational directions being opposite to each other, said first and second rotational velocities each being generally equal to a preselected multiple of the rotational velocity of said crankshaft, said first and second shafts being connected in torque transmitting association with said crankshaft, said first and second shafts being first and second rotors, respectively, of a supercharging device.

16. The engine of claim 15, further comprising:

a housing rigidly attached to said engine, said first and second shafts being supported by said housing for rotation within said housing.

17. The engine of claim 16, wherein:

said supercharging device is a Roots blower.

18. The engine of claim 17, wherein:

a first plane, bisecting each of said plurality of pistons and containing said vertical axis, extends between and is equidistant from said first and second axes of rotation.

19. The engine of claim 18, wherein:

said preselected multiple is two.

20. The engine of claim 19, wherein:

said plurality of pistons comprises four pistons connected to said crankshaft and said plurality of cylinders comprises four cylinders, said four cylinders being disposed in an in-line configuration.

21. The engine of claim 20, wherein:

said engine is a four cycle engine.

22. An engine of an outboard motor, comprising:

a crankshaft supported for rotation about a vertical axis;

a plurality of pistons connected to said crankshaft, each of said plurality of pistons being disposed for reciprocating movement within an associated one of a plurality of cylinders of said engine;

a first shaft supported for rotation about a first axis of rotation at a first rotational velocity in a first rotational direction, said first shaft having a first center of gravity which is radially displaced from said first axis of rotation by a first preselected amount;

a second shaft supported for rotation about a second axis of rotation at a second rotational velocity in a second rotational direction, said second shaft having a second center of gravity which is radially displaced from said second axis of rotation by a second preselected amount, said first and second axes of rotation being generally parallel to said vertical axis, said first and second rotational directions being opposite to each other, said first and second rotational velocities each being generally equal to a preselected multiple of the rotational velocity of said crankshaft, said first and second shafts being connected in torque transmitting association with said crankshaft, said first and second shafts being first and second rotors, respectively, of a supercharging device; and

a housing rigidly attached to said engine, said first and second shafts being supported by said housing for rotation within said housing.

23. The engine of claim 22, wherein:

said supercharging device is a Roots blower.

24. The engine of claim 23, wherein:

a first plane, bisecting each of said plurality of pistons and containing said vertical axis, extends between and is equidistant from said first and second axes of rotation.

25. The engine of claim 24, wherein:

said preselected multiple is two, said plurality of pistons comprises four pistons connected to said crankshaft, said plurality of cylinders comprises four cylinders, said four cylinders is disposed in an in-line configuration, and said engine is a four cycle engine.