US 5,282,397 A · Engine balancing system having at least one pivoting counterbalance weight

Abstract

The engine balancing system preferably has two pivoting counterbalance weights connected to eccentric journals on the crankshaft via their respective link arms. The use of the two pivoting weights and the particular geometrical relationships between the balancing system components enable the balancing system to substantially mimic and oppose the non-sinusoidal piston forces. Several methods of balancing the non-sinusoidal piston forces are disclosed. In a first method, the centers of gravity of the respective counterbalance weights are moved at non-sinusoidal angular accelerations. These angular accelerations are greater when the piston is near its Top Dead Center position than when the piston is near its Bottom Dead Center position to yield higher balancing forces when the piston is near Top Dead Center. In a second method, the centers of gravity move through arcs which are substantially parallel to the piston axis when the piston is near its Top Dead Center position, and move in directions less parallel to the piston axis when the piston is near its Bottom Dead Center position. The movement of the centers of gravity parallel to but in the opposite direction from the moving piston when the piston is near Top Dead Center results in greater balancing forces when the piston is near Top Dead Center. The invention also includes a combined method of balancing the non-sinusoidal piston forces. In this combined method, the angular accelerations of the centers of gravity vary as in the first method, and the directions of movement of the centers of gravity vary as in the second method.

Claims20

Dependent claims

In an engine having a cylinder in which a piston reciprocates along a piston axis, the piston being connected to a rotatable crankshaft that is mounted in a crankcase, an improved counterbalancing means comprising:

a first counterbalance weight having a first center of gravity located on a first side of said piston axis, said first center of gravity moving in a first arc during piston reciprocation;
a second counterbalance weight having a second center of gravity located on a second side of said piston axis, said second center of gravity moving in a second arc during piston reciprocation;
drive means interconnected with said crankshaft for moving said first and second counterbalance weights in response to rotation of said crankshaft;
and
pivot means interconnected with said crankcase for pivotally connecting said first and second counterbalance weights to said crankcase.

2 more elements

An internal combustion engine, comprising:

a rotatable crankshaft having a crankshaft axis;
a piston that reciprocates along a piston axis between a Top Dead Center position and a Bottom Dead Center position in response to the rotation of said crankshaft;
a crankcase;
a first counterbalance weight having a first center of gravity;
a first drive means interconnected with said crankshaft for pivoting said first counterbalance weight at a first movable pivot in response to crankshaft rotation, said first movable pivot having a first movable pivot axis;
a first pivot means interconnected with said crankcase for pivotally engaging said first counterbalance weight at a first stationary pivot, said first stationary pivot having a first stationary pivot axis;
a first plane containing said piston axis and said crankshaft axis;
a second plane containing said first movable pivot axis and said first stationary pivot axis, said second plane intersecting said first plane and said piston being disposed on a piston side of said second plane;
a third plane containing said crankshaft axis and said first movable pivot axis, said third plane intersecting said second plane;
wherein said first center of gravity is disposed on the piston side of said second plane;
and
wherein said second plane and said third plane are more nearly perpendicular to each other when said piston is at its Bottom Dead Center position than when said piston is at its Top Dead Center position.

9 more elements

An internal combustion engine, comprising:

a rotatable crankshaft having a crankshaft axis;
a piston that reciprocates along a piston axis between a Top Dead Center position and a Bottom Dead Center position in response to the rotation of said crankshaft;
a crankcase;
a first counterbalance weight having a first center of gravity;
a first drive means interconnected with said crankshaft for pivoting said first counterbalance weight at a first movable pivot in response to crankshaft rotation, said first movable pivot having a first movable pivot axis;
a first pivot means interconnected with said crankcase for pivotally engaging said first counterbalance weight at a first stationary pivot, said first stationary pivot having a first stationary pivot axis;
a first plane containing said piston axis and said crankshaft axis;
a second plane containing said first movable pivot axis and said first stationary pivot axis, said second plane intersecting said first plane and said piston lying on a piston side of said second plane;
a third plane containing said first stationary pivot axis and being perpendicular to said piston axis, said piston lying on a piston side of said third plane;
wherein the first center of gravity is located on the piston side of the second plane;
wherein the first center of gravity is located on the piston side of the third plane when the piston is at its Bottom Dead Center position;
and
wherein the first center of gravity is further from the third plane when the piston is at its Bottom Dead Center position than when the piston is at its Top Dead Center position.

10 more elements

Dependencies are inferred from the claim text.

Engine balancing system having at least one pivoting counterbalance weight

Life of this patent

Engine balancing system having at least one pivoting counterbalance weight

Life of this patent

Abstract

Claims20