Abstract: A method and apparatus of carrying out exhaust gas recirculation and compression release retarding is disclosed for use during both positive power and retarding operation of an overhead cam internal combustion engine. Energy is derived from an engine component and stored as potential energy. The stored energy is selectively applied to a valve actuator to carry out exhaust gas recirculation in an engine cylinder. The energy derived from the engine may be stored in the form of a compressed hydraulic fluid and selectively applied to the valve actuator with an electronically controlled trigger valve. The valve actuator may be a slave piston having an inner core and an outer sleeve capable of opening the valve of the cylinder in response to independent exhaust gas recirculation and compression release hydraulic systems.

Abstract: An apparatus and method for effectuating multi-cycle engine braking is disclosed. The present invention controls the operation of the engine valves to permit more than one compression release event during a single engine operating cycle. The apparatus includes an assembly for operating at least one exhaust valve of an engine cylinder during a positive power operation. The apparatus further includes an assembly for operating at least one intake valve of the engine cylinder. The apparatus further including an assembly for operating the at least one exhaust valve during an engine braking operation.

Abstract: An internal combustion engine may include a hydraulic linkage used to transfer motion from a valve train element, such as a cam, to an engine valve. Method and apparatus for selectively limiting the motion transferred by the hydraulic linkage from the valve train element to the engine valve are disclosed. The hydraulic linkage may comprise means for resetting or clipping the displacement of the engine valves into the engine cylinder following a compression release event. The hydraulic linkage may also limit the displacement of the engine valves into the engine cylinder for main exhaust and/or other valve events, as well as limit the overlap between a main exhaust valve event and an intake valve event.

Abstract: The present invention is directed to a locking assembly for use in a rocker arm assembly for an engine brake assembly. The rocker arm assembly includes a rocker arm pivotally mounted on a shaft. The rocker arm has a first end and a second end, wherein the first end includes a cam follower and the second end includes an actuator assembly for operating at least one valve during a braking operation. The improved rocker arm includes a locking assembly for releasably securing the rocker arm to the shaft to prevent pivoting of the rocker arm during a positive power operation. The locking assembly includes a releasable latching assembly located on one of the rocker arm and the shaft. The locking assembly also includes a latch receiving recess located on another of the rocker arm and the shaft. The releasable latching assembly engages the latch receiving recess during a positive power operation.

Abstract: Electronic controls for compression release engine retarders of internal combustion engines which provide electronic signals to control hydraulic valves assembled in the hydraulic actuators of the retarders, to open engine exhaust valves to provide compression release events. The electronic controls may produce signals for both opening and/or closing the controlled valves. The electronic controls may monitor various engine operating conditions and/or parameters with one or more sensors distributed in the engine and vehicle in which the engine is installed. The timing of valve actuation, particularly that for compression release events, can be automatically modified responsive to the level of engine operating conditions and parameters. Various operating routines for the electronic controls are also disclosed.

Abstract: A system and method for controlling a vacuum operated exhaust brake. A vehicle may be provided with service brake assistance and an exhaust brake, each of which may be driven by a common vacuum source. In the event the available vacuum is likely to be insufficient to meet the demand of the service brake assistance system, the exhaust brake may be selectively isolated from the vacuum source. Exhaust brake isolation may be responsive to a sensed vacuum parameter, such as the magnitude of the vacuum and/or the rate of change of the vacuum. Vacuum communication between the exhaust brake and the vacuum source may be reestablished responsive to the sensed vacuum parameter.

Abstract: An exhaust brake for an internal combustion engine is disclosed. The internal surfaces of the exhaust brake are aerodynamically shaped and sized to reduce the incidence of turbulent flow through the exhaust brake. The shape of the internal passage through the brake housing may be dictated by the requirement of maintaining as close to a laminar flow through the passage as possible when the brake valve is open. The ideal brake housings of the internal passage may be determined for exhaust brakes of various shapes and sizes. The ideal shapes may be typified as having non-uniform wall thicknesses. The ideal shapes of the internal brake surfaces, including that of the valve, may also be typified by the elimination of square edges (which trigger turbulence). Ideal flow through the exhaust brake may also be obtained by the reduction of bulk in the exhaust flow (minimization of the profile of the valve in the flow when the valve is open).

Abstract: An internal combustion engine has electrically controlled hydraulic linkages between engine cams and engine cylinder valves. If it is desired to skip a cam lobe or to modify the response of an engine cylinder valve to a cam lobe, hydraulic fluid is selectively released from the associated hydraulic linkage to permit lost motion between the cam and the engine cylinder valve. Electrically controlled hydraulic fluid valves are used to produce the selective release of hydraulic fluid from the hydraulic linkages. The mode of operation of the engine can be changed (e.g., from positive power mode to compression release engine braking mode or vice versa), or more subtle changes can be made to modify the timing and/or extent of engine cylinder valve openings to optimize engine performance for various engine or vehicle operating conditions (e.g., different engine or vehicle speeds).

Abstract: An internal combustion engine lost motion valve actuation system is disclosed. The system includes a variable length connection means connecting a force imparting means and an engine valve. The connection means may assume plural lengths to provide plural amounts of lost motion. The connection means may provide a maximum amount of lost motion which provides some minimum level of valve actuation suitable for a limp home operation of the engine. The connection means is operable for both engine positive power and engine braking modes of operation.

Abstract: A method and apparatus for carrying out variable timing exhaust gas recirculation is disclosed for use during both positive power and retarding operation of an internal combustion engine. Motion or energy is derived from an engine component and stored as potential energy. The stored energy is selectively applied to a valve actuator to carry out exhaust gas recirculation in an engine cylinder. The energy derived from the engine may be stored and selectively applied to the valve actuator with an electronically controlled trigger valve. The valve actuator may be a slave piston having an inner core and an outer sleeve capable of opening the valve of the cylinder in response to independent exhaust gas recirculation and compression release hydraulic systems.

Abstract: A method and apparatus of carrying out exhaust gas recirculation and compression release retarding is disclosed for use during both positive power and retarding operation of an internal combustion engine. Motion or energy is derived from an engine component and stored as potential energy. The stored energy is selectively applied to a valve actuator to carry out exhaust gas recirculation in an engine cylinder. The energy derived from the engine may be stored in the form of a compressed hydraulic fluid and selectively applied to the valve actuator with an electronically controlled trigger valve. The valve actuator may be a slave piston having an inner core and an outer sleeve capable of opening the valve of the cylinder in response to independent exhaust gas recirculation and compression release hydraulic systems.

Abstract: An internal combustion engine has engine cylinder intake and exhaust valves that are operated by intake and exhaust cams via hydraulic linkages. The hydraulic linkages have selective lost motions that allow selective modification of the openings and closings of the engine cylinder valves. These modifications may also include complete omission of all response to particular lobes on the cams. The hydraulic linkages may be interconnected so that some intake valve openings are produced by an exhaust cam lobe and/or some exhaust valve openings are produced by an intake cam lobe. The linkages and linkage interconnections are preferably controlled electronically. The engine is preferably operable in either four-cycle positive power mode or two-cycle compression release engine braking mode. The intake cam may have plural lobes or only one lobe, while the exhaust cam may only have one lobe.

Abstract: Electronic controls for compression release engine brakes of the type having electrically controlled valves for selectively applying high pressure hydraulic fluid to hydraulic actuators which open exhaust valves in the associated internal combustion engine to produce compression release events in the engine. The electronic controls may produce signals for both opening and closing the electrically controlled valves. The electronic controls may monitor various operating conditions of the engine and the vehicle powered by the engine and may automatically modify the timing of the compression release events in accordance with those conditions.

Abstract: An internal combustion engine has electrically controlled hydraulic linkages between engine cams and engine cylinder valves. If it is desired to skip a cam lobe or to modify the response of an engine cylinder valve to a cam lobe, hydraulic fluid is selectively released from the associated hydraulic linkage to permit lost motion between the cam and the engine cylinder valve. Electrically controlled hydraulic fluid valves are used to produce the selective release of hydraulic fluid from the hydraulic linkages. The mode of operation of the engine can be changed (e.g., from positive power mode to compression release engine braking mode or vice versa), or more subtle changes can be made to modify the timing and/or extent of engine cylinder valve openings to optimize engine performance for various engine or vehicle operating conditions (e.g., different engine or vehicle speeds).

Abstract: A camless internal combustion engine has electronically or computer controlled, electrically operated hydraulic actuators for selectively opening the engine cylinder valves. The engine is capable of operating in either positive power mode or compression release engine braking mode. The pressure of the hydraulic fluid available for application to the hydraulic actuators is automatically adjusted from a relatively low pressure during positive power mode to a relatively high pressure during compression release engine braking mode. The stroke lengths of the engine cylinder valves may be automatically adjusted for various engine operating conditions using feedback loops that include sensors for detecting the amount of opening of each engine cylinder valve whose stroke length is to be controlled in this manner. The shapes of the valve opening and closing trajectories as a function of engine crank angle may similarly be varied in many other respect.

Abstract: An internal combustion engine has engine cylinder intake and exhaust valves that are operated by intake and exhaust cams via hydraulic linkages. The hydraulic linkages have selective lost motions that allow selective modification of the openings and closings of the engine cylinder valves. These modifications may include complete omission of all response to particular lobes on the cams. The hydraulic linkages may be interconnected so that some intake valve openings are produced by an exhaust cam lobe and/or some exhaust valve openings are produced by an intake cam lobe. The linkages and linkage interconnections are preferably controlled electronically. The engine is preferably operable in either four-cycle positive power mode or two-cycle compression release engine braking mode.

Abstract: In engine brakes of the type in which a master piston is reciprocated by an associated internal combustion engine part to hydraulically pressurize hydraulic fluid in a plenum, after which a trigger valve is opened to apply that hydraulic pressure to a slave piston which opens an exhaust valve in the engine to produce a compression release event, an electronically controlled trigger valve is used in place of the conventional mechanically operated trigger valve. The electronically controlled trigger valve can be much simpler and cheaper than the mechanical trigger valve it replaces, and it can also be readily controlled to automatically vary the timing of the compression release events if desired.

Abstract: A clip valve for limiting the stroke of an exhaust-valve-operating hydraulic actuator piston in a compression release engine brake has a plunger which follows the actuator piston down until the motion of the plunger is stopped by a retaining ring in a bore in which the plunger reciprocates. When the plunger is thus stopped, an aperture in the slave piston is uncovered, thereby allowing pressurized hydraulic fluid to escape from the actuator piston cylinder and preventing further downward motion of the actuator piston. The clip valve apparatus is constructed to facilitate assembly of the plunger and retaining ring in the bore, as well as to provide secure and fail-safe retention of those components in the bore. The parts of the clip valve are simplified and preferably also reduced in number as compared to the prior art.

Abstract: In a compression release engine brake for increasing the braking available from an associated internal combustion engine, an electrically controlled hydraulic valve having at least two coils and at least two positions is used to apply high pressure hydraulic fluid to a hydraulic actuator for opening an exhaust valve in the engine when a compression release event in the engine is desired. After each compression release event, the valve is switched to a condition in which it allows hydraulic fluid to drain from the hydraulic actuator, thereby allowing the associated engine exhaust valve to close.

Abstract: The slave piston drive train in a compression release engine braking system includes a slave piston with a rigidly connected extension. The end of the extension remote from the main body of the slave piston is spherically convex. A bearing pad or foot fits in swivel fashion on this spherically convex end. The outer surface of the foot opposite the spherically convex extension end is substantially flat and bears on a substantially flat surface on an exhaust valve rocker arm.