A valve train assembly includes at least a number of exhaust valves; at least one camshaft with at least a pair of a primary lift cam and an engine brake lift cam. A number of rocker arms each include a cam follower for following one of the primary lift cam and the engine brake lift cam. One rocker arm includes a cam follower following an engine brake lift cam. The rocker arm is provided with an engine brake capsule. Various biasing assemblies are disclosed that cooperate with one of the rocker arms of which the cam follower follows an engine brake lift cam to accommodate mechanical lash.

A valve timing adjusting device adjusts an opening/closing timing of a first valve driven by a rotation of a first camshaft and an opening/closing timing of a second valve driven by a rotation of a second camshaft. The valve timing adjusting device includes a first driving circuit controlling a first motor configured to generate a torque to shift a rotation phase of the first camshaft and a second driving circuit controlling a second motor configured to generate a torque to shift a rotation phase of the second camshaft. A first switching element of the first driving circuit operates at a switching frequency that is different from that of a second switching element of the second driving circuit.

An electromagnetic valve actuator (100) and method of control thereof. The electromagnetic valve actuator is for at least one valve (300) of an internal combustion engine (40), the electromagnetic valve actuator comprising: a rotor (102); a stator (101) for rotating the rotor; output means (104, 106) for actuating the valve in dependence on rotation of the rotor; mechanical energy storage means (108, 110, 116, 118) arranged to store energy in dependence on rotation of the rotor and release the energy to assist rotation of the rotor; and phase varying means (400) for varying a phase between the mechanical energy storage means and the output means.

A linkage for coupling between an actuator and a valve in an engine valve actuation assembly. The linkage provides some compliance in the operation of the linkage to close the valve. The linkage comprises a rocker having a rigid body portion, the body portion including a pivot axis about which it is rotatable, and a link mount for coupling to a valve link arm. The link mount is moveable from a rest position relative to the body portion, and the link mount is urged back towards its rest position when displaced from its rest position relative to the body portion.

An opposed-piston engine optionally contains an ignition system that is at least partially contained within the combustion chamber to enhance the combustion efficiency of a fuel-air mixture within the combustion system. More specifically, the ignition system contains at least one spark plug having an elongated center electrical delivery electrode, and, an elongated ground electrode. Accordingly, the elongated electrodes extend from an area adjacent to the inner periphery of the cylinder to a radially central area within the combustion chamber. Yet further, a cooling jacket is incorporated to provide cooling of the spark plug.

A four-stroke opposed piston engine contains a drive train containing two outer crank shaft gears, and two inner synchro gears, wherein the inner synchro gears are twice the diameter of the outer crank shaft gears. Additionally, novel piston faces are presented that when fixed on opposed pistons, create annular cavities that form advantageous combustion chambers when the pistons are at top dead center.

A valve train assembly includes at least a number of exhaust valves; at least one camshaft with at least a pair of a primary lift cam and an engine brake lift cam. A number of rocker arms each include a cam follower for following one of the primary lift cam and the engine brake lift cam. One rocker arm includes a cam follower following an engine brake lift cam. The rocker arm is provided with an engine brake capsule. Various biasing assemblies are disclosed that cooperate with one of the rocker arms of which the cam follower follows an engine brake lift cam to accommodate mechanical lash.

A valve actuation system comprises a valve actuation motion source configured to provide a main valve actuation motion and an auxiliary valve actuation motion for actuating at least one engine valve via a valve actuation load path. A lost motion subtracting mechanism is arranged in the valve actuation load path and configured, in a first default operating state, to convey at least the main valve actuation motion and configured, in a first activated state, to lose the main valve actuation motion and the auxiliary valve actuation motion. Additionally, a lost motion adding mechanism configured, in a second default operating state, to lose the auxiliary valve actuation motion and configured, in a second activated state, to convey the auxiliary valve actuation motion, wherein the lost motion adding mechanism is in series with the lost motion subtracting mechanism in the valve actuation load path at least during the second activated state.

A desmodromic valve train (20) for an engine (40), comprising a valve actuator (100) arranged to actuate a valve (400) independently of the crank angle of the engine (40), wherein the desmodromic valve train (20) comprises: a load path arrangement comprising an input arranged to receive actuating force from the valve actuator (100), an output arranged to provide the actuating force to the valve (400), and mechanical advantage means arranged such that a first displacement, of the input, causes a second displacement, of the output, wherein the second displacement is a multiple of the first displacement, the multiple being within the range 1.3 to 1.95.

A desmodromic valve train (20) for an engine (40), comprising a valve actuator (100) arranged to actuate a valve (400) independently of the crank angle of the engine (40), wherein the desmodromic valve train (20) comprises: a load path arrangement comprising an input arranged to receive actuating force from the valve actuator (100), an output arranged to provide the actuating force to the valve (400), and mechanical advantage means arranged such that a first displacement, of the input, causes a second displacement, of the output, wherein the second displacement is a multiple of the first displacement, the multiple being within the range 1.3 to 1.95.