Dedicated rocker arm engine brake
View Patent ↗A system for actuating an engine valve is disclosed. The system may include a rocker arm shaft ( 110 ) having a control fluid supply passage ( 112 ) and an exhaust rocker arm ( 500 ) pivotally mounted on the rocker arm shaft ( 110 ). A cam ( 210 ) for imparting main exhaust valve actuation to the exhaust rocker arm ( 500 ) may contact a cam roller associated with the exhaust rocker arm. A valve bridge ( 300 ) may be disposed between the exhaust rocker arm ( 500 ) and first and second engine valves ( 400, 450 ). A sliding pin ( 310 ) may be provided in the valve bridge ( 300 ), said sliding pin contacting the first engine valve ( 400 ). An engine braking rocker arm ( 100 ) may be pivotally mounted on the rocker arm shaft ( 110 ) adjacent to the exhaust rocker arm ( 500 ). The engine braking rocker arm may have a central opening, a hydraulic passage ( 102 ) connecting the central opening with a control valve ( 130 ), and a fluid passage ( 105 ) connecting the control valve with an actuator piston assembly ( 140 ). The actuator piston assembly may include an actuator piston ( 141 ) adapted to contact the sliding pin ( 310 ) during engine braking operation. A bushing ( 115 ) may be disposed between the engine braking rocker arm ( 100 ) and the rocker arm shaft ( 110 ). The bushing may have a port ( 118 ) which registers with the hydraulic passage ( 102 ). A cam ( 200 ) is provided for imparting engine braking actuation to the engine braking rocker arm ( 100 ). A plate ( 122 ) is fastened to a back end of the engine braking rocker arm ( 100 ), and a spring ( 124 ) biases the plate and the engine braking rocker arm ( 110 ) into contact with the cam ( 200 ).
1. A system for actuating an engine exhaust valve for engine braking comprising:
a rocker arm shaft ( 110 ) having a control fluid supply passage ( 112 );
an engine braking rocker arm ( 100 ) pivotally mounted on the rocker arm shaft ( 110 ), said engine braking rocker arm having a central opening disposed about the rocker arm shaft ( 110 ), a hydraulic passage ( 102 ) connecting the central opening with a control valve ( 130 ), and a fluid passage ( 105 ) connecting the control valve with an actuator piston assembly ( 140 );
a valve bridge ( 300 ) extending between first and second engine exhaust valves ( 400 , 450 );
a sliding pin ( 310 ) provided in the valve bridge ( 300 ), said sliding pin contacting the first engine exhaust valve ( 400 ), wherein the actuator piston assembly ( 140 ) contacts the sliding pin ( 310 );
a cam ( 200 ) for imparting engine braking actuation to the engine braking rocker arm ( 100 ); and
a spring ( 124 ) biasing the engine braking rocker arm ( 100 ) into contact with the cam ( 200 ).
2. The system of claim 1 , further comprising:
an exhaust rocker arm ( 500 ) pivotally mounted on the rocker arm shaft ( 110 ) adjacent to the engine braking rocker arm ( 100 ); and
a cam ( 210 ) for imparting main exhaust valve actuation to the exhaust rocker arm ( 500 ).
3. The system of claim 2 , further comprising:
a plate ( 122 ) fastened to a back end of the engine braking rocker arm ( 100 ), said plate including a central raised portion ( 123 ) which receives an end of the spring ( 124 ), a front tab ( 125 ) and two side tabs ( 127 ), said tabs ( 125 , 127 ) engaging mating slots in the engine braking rocker arm ( 100 ).
4. The system of claim 3 , further comprising:
a bushing ( 115 ) disposed between the engine braking rocker arm ( 100 ) and the rocker arm shaft ( 110 ), said bushing having a slot ( 116 ), and a port ( 118 ) which registers with the hydraulic passage ( 102 ).
5. The system of claim 4 , wherein the actuator piston assembly comprises:
a slide-able actuator piston ( 141 ) disposed in a bore provided in the engine braking rocker arm, said actuator piston having a hollow interior;
a lash adjustment screw ( 142 ) extending through the engine braking rocker arm ( 100 ) into the hollow interior of the actuator piston ( 141 ), said lash adjustment screw having an enlarged portion at a bottom end;
a collar ( 143 ) fixed in an upper portion of the hollow interior of the actuator piston ( 141 ); and
a spring ( 144 ) provided between the collar ( 143 ) and the enlarged portion of the bottom end of the lash adjustment screw ( 142 ).
6. The system of claim 5 , wherein the control valve comprises:
a control valve piston ( 131 ) having an internal passage ( 132 ); and
a spring ( 133 , 134 ) biasing the control valve piston ( 131 ) into the engine braking rocker arm ( 100 ).
7. The system of claim 6 , wherein the sliding pin ( 310 ) comprises a shoulder at a mid-portion, and the valve bridge ( 300 ) comprises a bore with a mating shoulder for the sliding pin shoulder.
8. The system of claim 1 , further comprising:
a plate ( 122 ) fastened to a back end of the engine braking rocker arm ( 100 ), said plate including a central raised portion ( 123 ) which receives an end of the spring ( 124 ), a front tab ( 125 ) and two side tabs ( 127 ), said tabs ( 125 , 127 ) engaging mating slots in the engine braking rocker arm ( 100 ).
9. The system of claim 1 , further comprising:
a bushing ( 115 ) disposed between the engine braking rocker arm ( 100 ) and the rocker arm shaft ( 110 ), said bushing having a slot ( 116 ), and a port ( 118 ) which registers with the hydraulic passage ( 102 ).
10. The system of claim 1 , wherein the actuator piston assembly comprises:
a slide-able actuator piston ( 141 ) disposed in a bore provided in the engine braking rocker arm, said actuator piston having a hollow interior;
a lash adjustment screw ( 142 ) extending through the engine braking rocker arm ( 100 ) into the hollow interior of the actuator piston ( 141 ), said lash adjustment screw having an enlarged portion at a bottom end;
a collar ( 143 ) fixed in an upper portion of the hollow interior of the actuator piston ( 141 ); and
a spring ( 144 ) provided between the collar ( 143 ) and the enlarged portion of the bottom end of the lash adjustment screw ( 142 ).
11. The system of claim 1 , wherein the control valve comprises:
a control valve piston ( 131 ) having an internal passage ( 132 ); and
a spring ( 133 , 134 ) biasing the control valve piston ( 131 ) into the engine braking rocker arm ( 100 ).
12. The system of claim 1 , wherein the sliding pin ( 310 ) comprises a shoulder at a mid-portion, and the valve bridge ( 300 ) comprises a bore with a mating shoulder for the sliding pin shoulder.
13. A system for actuating an engine valve comprising:
a rocker arm shaft ( 110 ) having a control fluid supply passage ( 112 );
an exhaust rocker arm ( 500 ) pivotally mounted on the rocker arm shaft ( 110 );
a cam ( 210 ) for imparting main exhaust valve actuation to the exhaust rocker arm ( 500 );
a valve bridge ( 300 ) disposed between the exhaust rocker arm ( 500 ) and first and second engine valves ( 400 , 450 );
a sliding pin ( 310 ) provided in the valve bridge ( 300 ), said sliding pin contacting the first engine valve ( 400 );
an engine braking rocker arm ( 100 ) pivotally mounted on the rocker arm shaft ( 110 ) adjacent to the exhaust rocker arm ( 500 ), said engine braking rocker arm having a central opening, a hydraulic passage ( 102 ) connecting the central opening with a control valve ( 130 ), and a fluid passage ( 105 ) connecting the control valve with an actuator piston assembly ( 140 ), wherein the actuator piston assembly includes an actuator piston ( 141 ) adapted to contact the sliding pin ( 310 );
a bushing ( 115 ) disposed between the engine braking rocker arm ( 100 ) and the rocker arm shaft ( 110 ), said bushing having a port ( 118 ) which registers with the hydraulic passage ( 102 );
a cam ( 200 ) for imparting engine braking actuation to the engine braking rocker arm ( 100 );
a plate ( 122 ) fastened to a back end of the engine braking rocker arm ( 100 ); and
a spring ( 124 ) contacting the plate ( 122 ) and biasing the engine braking rocker arm ( 100 ) into contact with the cam ( 200 ).