US 10,767,516 B2 · Synchronous drive apparatus with adjustable non-circular drive elements

Abstract

A synchronous drive is provided in which a non-circular rotor generates a fluctuating corrective torque to counteract a fluctuating load torque on a driven rotor. The angular orientation of the non-circular rotor can vary relative to the driven rotor so as to change the phase angle of the fluctuating corrective torque relative to the driving rotor. The arrangement may be applied in internal combustion engines with variable valve timing (VVT) systems, wherein the phase angle of a fluctuating load torque presented on a cam rotor, due to forces arising from actuation of intake and/or exhaust valves by the camshaft, varies relative to the crankshaft. The phase angle of the fluctuating corrective torque is also varied relative to the crankshaft to maintain phase relationship with the fluctuating load torque and thereby maintain reduced cam torsional vibrations and span tensions provided by the non-circular rotor during operation.

Claims20

Dependent claims

A corrective system for an internal combustion engine, said engine having a crankshaft driven by combustion energy, a camshaft that actuates one or more combustion valves, and a variable valve timing (VVT) system for controlling the timing of the actuation of the one or more valves by the camshaft relative to the crankshaft, the corrective system comprising:

a cam rotor that is operatively connectable with the camshaft;
a synchronous endless drive arrangement including a continuous-loop elongate drive structure engaging the crankshaft and the non-circular rotor;
wherein the cam rotor has a peripheral edge engaging the elongate drive structure, said peripheral edge having a non-circular profile including a plurality of protruding rotor portions which alternate with receding rotor portions, wherein the angular positions of the protruding and receding rotor portions are adjustable relative to the crankshaft;
and
an actuator adjusting the angular positions of the protruding and receding rotor portions relative to the crankshaft during operation of the engine.

2 more elements

A method of operating a synchronous endless drive arrangement for an internal combustion engine having a crankshaft and a camshaft with a variable valve timing (VVT) arrangement, wherein a fluctuating load torque is applied by at least one combustion valve on the camshaft, the method comprising:

(a) operating the engine;
(b) applying a fluctuating corrective torque on the camshaft to substantially counteract the fluctuating load torque, whilst the engine operates with the VVT in a nominal timing position;
(c) varying the timing between the camshaft and the crankshaft, thereby varying a phase angle of the fluctuating load torque relative to the crankshaft, whilst the engine operates;
and
(d) in conjunction with (c), varying a phase angle of the fluctuating corrective torque relative to the crankshaft to maintain substantial counteraction of the fluctuating load torque.

2 more elements

Dependencies are inferred from the claim text.

Synchronous drive apparatus with adjustable non-circular drive elements

Life of this patent

Synchronous drive apparatus with adjustable non-circular drive elements

Life of this patent

Abstract

Claims20