Hydraulic lash adjuster with compression release brake

An assembly for operating an engine valve comprising:

• a rocker shaft;
• a rocker arm pivotally mounted on the rocker shaft, said rocker arm including a cavity at a valve actuation end;
• a hydraulic lash adjuster slidably disposed in the rocker arm cavity;
• a hydraulic passage provided in the rocker arm, said passage communicating with the rocker arm cavity;
• and
• means for (a) supplying hydraulic fluid to the passage during a positive power mode of engine operation, (b) selectively cutting off the supply of hydraulic fluid during the positive power mode of operation in response to the determination of a need for a change in engine valve timing, lift, or overlap, and (c) cutting off the supply of hydraulic fluid to the passage during an engine braking mode of engine operation.

An assembly for operating an engine valve comprising:

• a rocker shaft;
• a rocker arm pivotally mounted on the rocker shaft, the rocker arm including a cavity at a valve actuation end, the cavity having an end wall;
• a lash adjuster disposed in the rocker arm cavity;
• and
• means for (a) activating the lash adjuster during a positive power mode of engine operation and (b) deactivating the lash adjuster during an engine braking mode of engine operation.

An assembly for operating an engine valve comprising:

• a rocker shaft;
• a rocker arm pivotally mounted on the rocker shaft, said rocker arm including a cavity at a valve actuation end;
• a lash adjuster slidably disposed in the rocker arm cavity;
• and
• means for (a) selectively activating and deactivating the lash adjuster during a positive power mode of engine operation in response to the determination of a need for a change in engine valve timing, lift, or overlap, and (b) deactivating the lash adjuster during an engine braking mode of engine operation.

An engine valve lash adjuster comprising:

• an outer plunger;
• an inner plunger slidably received in the outer plunger;
• a check valve in the inner plunger;
• a spring disposed between the inner plunger and the outer plunger, the spring adapted to bias the inner and outer plungers apart;
• and
• a spring stop disposed between the spring and the inner plunger.

A method of operating an engine valve lash adjuster disposed in a rocker arm in an internal combustion engine, the method comprising the steps of:

• determining that the engine is operating in a positive power mode;
• supplying hydraulic fluid to the lash adjuster in response to the determination that the engine is operating in a positive power mode of operation;
• determining that the engine is operating in an engine braking mode;
• and
• cutting off the supply of hydraulic fluid to the lash adjuster in response to a determination that the engine is operating in an engine braking mode of operation.

A method of operating an engine valve lash adjuster in an internal combustion engine comprising the steps of:

• determining that an engine is operating in a positive power mode;
• supplying hydraulic fluid to a lash adjuster in response to a determination that the engine is operating in a positive power mode of operation;
• determining whether a change in engine valve timing, lift, or overlap is required;
• selectively cutting off the supply of hydraulic fluid to the lash adjuster in response to a determination of a required change in engine valve timing, lift, or overlap;
• determining that the engine is operating in an engine braking mode;
• and
• cutting off the supply of hydraulic fluid to the lash adjuster in response to a determination that the engine is operating in an engine braking mode of operation.

A method of operating an engine valve lash adjuster in an internal combustion engine, the method comprising the steps of:

• determining that the engine is operating in a positive power mode;
• activating the lash adjuster in response to the determination that the engine is operating in a positive power mode of operation;
• determining that the engine is operating in an engine braking mode;
• and
• deactivating the lash adjuster in response to a determination that the engine is operating in an engine braking mode of operation.

A method of operating an engine valve lash adjuster in an internal combustion engine comprising the steps of:

• determining that an engine is operating in a positive power mode;
• activating the lash adjuster in response to a determination that the engine is operating in a positive power mode of operation;
• determining whether a change in engine valve timing, lift, or overlap is required;
• selectively deactivating the lash adjuster in response to a determination of a required change in engine valve timing, lift, or overlap;
• determining that the engine is operating in an engine braking mode;
• and
• deactivating the lash adjuster in response to a determination that the engine is operating in an engine braking mode of operation.