Back to results
US 8,757,123 B2Granted
Balancing an opposed-piston, opposed-cylinder engine
AssigneeEcoMotors, Inc.
InventorPeter Hofbauer
Life of this patent
Estimating the term…
Abstract
An opposed-piston, opposed-cylinder engine in which the intake and exhaust pistons are symmetrically arranged has a small inertial force imbalance in the direction of reciprocation of the pistons. A center of gravity of the crankshaft can be displaced from the axis of rotation to at least partially overcome this imbalance. Such counterweighting of the crankshaft cancels a portion of the inertial balance due to the pistons but introduces an inertial imbalance in an orthogonal direction with respect to the piston-induced imbalance. By providing additional counterweights on pulleys rotating at the same speed, but the opposite direction, as the crankshaft, the imbalance can be substantially eliminated to yield substantially a perfectly-balanced engine.
Claims19
An internal combustion engine, comprising:
- a first cylinder having a central axis;
- a second cylinder having a central axis parallel to the central axis of the first cylinder;
- a unitary crankshaft situated between the two cylinders and having at least five journals and four webs:
- a front main journal having a central axis collinear with an axis of rotation of the crankshaft;
- a rear main journal having a central axis collinear with the axis of rotation of the crankshaft;
- a central eccentric journal;
- a front eccentric journal between the front main journal and the central eccentric journal;
- a rear eccentric journal between the rear main journal and the central eccentric journal;
- a front outer web located between the front main journal and the front eccentric journal;
- a front inner web located between the front eccentric journal and the central eccentric journal;
- a rear inner web located between the central eccentric journal and the rear eccentric journal;
- a rear outer web located between the rear eccentric journal and the rear main journal;
- wherein:
- a central axis of the front and rear eccentric journals is offset from the axis of rotation by an outer crank throw;
- a central axis of the central journal is offset from the axis of rotation by an inner crank throw;
- the front and rear eccentric journals are substantially equally phased;
- and
- the central eccentric journal is asymmetrically phased with respect to the front and rear eccentric journals;
- the engine further comprising:
- a first piston disposed in the first cylinder and coupled to the central eccentric journal via a first pushrod;
- a second piston disposed in the second cylinder and coupled to the central eccentric journal via a second pushrod;
- a third piston disposed in the first cylinder and coupled to the front eccentric journal via a first pullrod and coupled to the rear eccentric journal via a second pullrod;
- and
- a fourth piston disposed in the second cylinder and coupled to the front eccentric journal via a third pullrod and coupled to the rear eccentric journal via a fourth pullrod,
- wherein:
- reciprocation of the pistons, the pushrods, and the pullrods generates an unbalanced inertia force;
- the front inner web includes a first counterweight;
- the rear inner web includes a second counterweight;
- the first and second counterweights cause the center of gravity to be displaced from the axis of rotation of the crankshaft to at least partially counteract the unbalanced inertia force;
- a crankshaft pulley coupled to the crankshaft;
- an accessory pulley counter rotating at the same speed as the crankshaft pulley with the crankshaft pulley and the accessory pulley engaged via a flexible member;
- an accessory shaft and an accessory coupled to and rotating with the accessory pulley;
- and
- a counterweight coupled to the accessory shaft.
31 more elements
An internal combustion engine system, comprising:
- a crankshaft having at least five journals and four webs:
- a front main journal having a central axis collinear with an axis of rotation of the crankshaft;
- a rear main journal having a central axis collinear with the axis of rotation of the crankshaft;
- a central eccentric journal;
- a front eccentric journal between the front main journal and the central eccentric journal;
- a rear eccentric journal between the rear main journal and the central eccentric journal;
- a front outer web located between the front main journal and the front eccentric journal;
- a front inner web located between the front eccentric journal and the central eccentric journal;
- a rear inner web located between the central eccentric journal and the rear eccentric journal;
- a rear outer web located between the rear eccentric journal and the rear main journal;
- a first cylinder having a first piston reciprocating therein, the first piston coupled to the crankshaft via a first connecting rod;
- a second cylinder having a second piston reciprocating therein, the second piston coupled to the crankshaft via a second connecting rod;
- a third piston reciprocating in the first cylinder, the third piston coupled to the crankshaft via third and fourth connecting rods;
- a fourth piston reciprocating in the second cylinder, the fourth piston coupled to the crankshaft via fifth and sixth connecting rods;
- a crankshaft pulley coupled to the crankshaft;
- an accessory pulley counter rotating at the same speed as the crankshaft pulley with the crankshaft pulley and the accessory pulley engaged via a flexible member;
- and a
- an accessory counterweight coupled to the accessory pulley.
15 more elements
An internal combustion engine, comprising:
- a first cylinder having a central axis;
- a second cylinder having a central axis parallel to the central axis of the first cylinder;
- a unitary crankshaft situated between the two cylinders and having at least five journals and four webs:
- a front main journal having a central axis collinear with an axis of rotation of the crankshaft;
- a rear main journal having a central axis collinear with the axis of rotation of the crankshaft;
- a central eccentric journal;
- a front eccentric journal between the front main journal and the central eccentric journal;
- a rear eccentric journal between the rear main journal and the central eccentric journal;
- a front outer web located between the front main journal and the front eccentric journal;
- a front inner web located between the front eccentric journal and the central eccentric journal;
- a rear inner web located between the central eccentric journal and the rear eccentric journal;
- a rear outer web located between the rear eccentric journal and the rear main journal;
- wherein:
- a central axis of the front and rear eccentric journals is offset from the axis of rotation by an outer crank throw;
- a central axis of the central journal is offset from the axis of rotation by an inner crank throw;
- the front and rear eccentric journals are substantially equally phased;
- and
- the central eccentric journal is asymmetrically phased with respect to the front and rear eccentric journals;
- the engine system further comprising:
- a first piston disposed in the first cylinder and coupled to the central eccentric journal via a first pushrod;
- a second piston disposed in the second cylinder and coupled to the central eccentric journal via a second pushrod;
- a third piston disposed in the first cylinder and coupled to the front eccentric journal via a first pullrod and coupled to the rear eccentric journal via a second pullrod;
- and
- a fourth piston disposed in the second cylinder and coupled to the front eccentric journal via a third pullrod and coupled to the rear eccentric journal via a fourth pullrod;
- a crankshaft pulley coupled to the crankshaft;
- an accessory pulley counter rotating at the same speed as the crankshaft pulley with the crankshaft pulley and the accessory pulley engaged via a flexible member;
- and a
- a counterweight coupled to the accessory pulley,
- wherein:
- reciprocation of the pistons, the pushrods, and the pullrods generates an unbalanced inertia force;
- and
- the crankshaft has a center of gravity displaced from the axis of rotation of the crankshaft to at least partially counteract the unbalanced inertia force.
29 more elements
Dependencies are inferred from the claim text.