Exhaust valve mechanism for an internal combustion engine

Exhaust valve mechanism for an internal combustion engine with at least one exhaust valve in each engine cylinder, comprising:

• a main rocker arm for each cylinder mounted on a rocker arm shaft for normal operation of the exhaust valve by actuation by a camshaft cam element;
• and
• a secondary rocker arm arranged on the main rocker aim and mounted on the rocker arm shaft for activation of an exhaust brake mode, which activation is achieved through supply of hydraulic pressure to a piston cylinder arrangement acting between the main and secondary rocker arms,
• the piston cylinder arrangement comprising a master piston and a slave piston connected by a hydraulic link which allows activation by increased hydraulic pressure supplied to increase the piston stroke length of the hydraulic link, wherein the master piston, during activation of an exhaust gas temperature increasing mode, is moved from an inactive position to an active position by the hydraulic pressure for a part of its stroke length against the spring force of a first resilient member and for the rest of its stroke length against the combined spring forces of the first resilient member and a second resilient member, and that the end of the first stroke length defines a position for the master piston that allows the activation of an extra valve event, the first resilient member is a helical spring positioned between the master piston and a stopper ring to bias the master piston towards an inactive end position, and the stopper ring is provided with a set of apertures for a corresponding set of distance rods reaching through the stopper ring to define an intermediate position for the master piston.

Exhaust valve mechanism for an internal combustion engine with at least one exhaust valve in each engine cylinder, comprising:

• a main rocker arm for each cylinder mounted on a rocker arm shaft for normal operation of the exhaust valve by actuation by a camshaft cam element;
• and
• a secondary rocker arm arranged on the main rocker arm and mounted on the rocker arm shaft for activation of an exhaust brake mode, which activation is achieved through supply of hydraulic pressure to a piston cylinder arrangement acting between the main and secondary rocker arms,
• the piston cylinder arrangement comprising a master piston and a slave piston connected by a hydraulic link which allows activation by increased hydraulic pressure supplied to increase the piston stroke length of the hydraulic link, wherein the master piston, during activation of an exhaust gas temperature increasing mode, is moved from an inactive position to an active position by the hydraulic pressure for a part of its stroke length against the spring force of a first resilient member and for the rest of its stroke length against the combined spring forces of the first resilient member and a second resilient member, and that the end of the first stroke length defines a position for the master piston that allows the activation of an extra valve event, wherein the second resilient member is a U-shaped leaf spring.