Abstract: A valve actuation device for an internal combustion engine having at least one combustion cylinder, a piston positioned within said cylinder for reciprocal motion therein; a pressurized hydraulic fluid gallery in a closed lubrication system; at least one valve in gas exchange communication for either intake or exhaust, said valve equipped with a valve spring and a seat and moveable between an open and closed position as controlled by said valve actuation device, a cam shaft with a cam for actuating said valve synchronously with said piston motion, said valve actuation device comprising: a cam configured for primary and secondary valve motion; a cam follower to transmit cam movement through a hydraulic circuit in fluid communication with said hydraulic fluid gallery into the valve between an open and closed position, and a fixed stroke accumulator selectively hydraulically controlled in said hydraulic circuit for loosing a portion of cam follower motion and to effect valve motion; an electro-hydraulic control

Abstract: A method and an apparatus for controlling combustion engine compression braking has the variable timing of the opening of at least one exhaust valve by an electronic control module within each one of the engine cylinders and within a time range of 15°-150° before the top-dead-center position of each cylinder piston during each compression stroke such that variable compression braking power levels, and attendant noise levels, can be obtained as required or desired dependent upon various road, vehicle, and vehicle location parameters. The system and method facilitate a wide range of braking power levels or values, the braking power is smoothly modulated as a result of all of the designated exhaust valves of the cylinders being activated, and the braking power levels can also be generated as a function of engine speed.

Abstract: A method of engine compression release braking includes an initial step of compressing gas in an engine cylinder. A compression release brake valve is then opened at least in part by fluidly connecting a brake actuator to a source of high pressure actuation fluid. Next, a valve closing timing that results a valve seating velocity that is less than a pre-determined velocity is determined. The compression release brake valve is then closed at the valve closing timing at least in part by fluidly connecting the brake actuator to a low pressure actuation fluid reservoir.

Abstract: An integral engine fueling and engine compression braking hydraulically actuated, electronically controlled unit injector (HEUI) system comprises a fuel injection piston. A brake rocker arm extends transversely through the fuel injector and axially accommodates the fuel injector plunger and plunger return spring. The brake rocker arm is also operatively connected to the engine exhaust valve rocker arm, and a camming shaft, having a flat or planar surface portion, is operatively connected to an end portion of the brake rocker arm. When the end portion of the brake rocker arm is disposed in contact with the flat or planar surface portion of the camming shaft, normal fuel injection can occur in accordance with an electronic control module (ECM).

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. The apparatus further including an assembly for selectively operating the at least one exhaust valve during an engine braking operation.

Abstract: The present invention relates to methods of improving engine braking of a reciprocating piston internal combustion engine by variable valve actuation. One embodiment of the present invention enables independent two-valve actuation for each cylinder, and engine braking horsepower can be optimized using two-valve braking at high engine speeds and one-valve braking at low speeds. Another embodiment of the present invention enables better a sequential valve actuation to reduce engine braking load and compliance. Another embodiment of the present invention enables better engine starting and warming up by controlling timing and lift of each valve.

Abstract: A torque based cam timing system and method for an engine having dual independent camshafts is disclosed that includes a first set of ROM based calibration tables containing values for intake valve closing and valve overlap that provide best fuel economy and emissions over the operating range of engine speed and engine indicated torque and a second set of ROM based calibration tables containing values for intake valve closing and valve overlap for optimal power over the operating range of engine speed. A power index value that indicates the change in driver desire from fuel economy to power, is used to interpolate over the range of values in the first set of tables to the values in the second set of tables to calculate values of intake valve closing and valve overlap that are optimal for all altitudes.

Abstract: A control method of an internal combustion engine with which braking force while reducing the speed of the motor vehicle can be established by generating pumping loss effectively by using a variable valve mechanism enabling to control arbitrarily the open-close timing and the lift amount of air intake and exhaust valves of the engine. When the break step-on force detection means detects a step-on force on a brake and an operation of the anti-lock brake system is selected, at least one of the intake valve or the exhaust valve is made close, another one not closed of the intake valve or the exhaust valve is made open once in a single revolution of the engine while a piston moves from a top dead center to a bottom dead center, and a lift of the valve is controlled to be a designated value.

Abstract: A compression release engine brake assembly adapted for use with an internal combustion engine, and an exhaust valve (29) operable to open in a normal exhaust lift event (FIG. 9) and in a brake lift event (FIG. 15). The engine includes an exhaust valve actuating mechanism (23,31,37) for imparting reciprocal movement to said exhaust valve (29) in response to rotation of a cam shaft (11) including a cam profile (13), a normal lift portion (17) and a brake lift portion (19). The assembly includes a lost motion device (75) moveable between a normal lost motion condition (FIG. 4) and an actuated condition (FIG. 14) in response to movement of an input member (91). An energy storage spring (117) is operable, after being compressed to an energy storage condition (FIG. 12) to be able to bias the input member (91) toward a second position, effecting the actuated condition of the lost motion device (75).

Abstract: An enhanced warm-up operation mode operates a first portion of engine cylinders in a power mode and a second portion of engine cylinders in a braking mode. More fuel is injected into the powered cylinders in order to maintain engine speed and overcome the retarding force of the engine compression release brakes on the braking cylinders. The engine cycles through which cylinders are powered and which are braking during the warm-up procedure. The process reduces emissions, such as white smoke, that are common during cold start conditions.

Abstract: A method for comprehensive integrated control of a compression-ignition internal combustion engine having integral fuel pump-injectors utilizing an electronic control unit is disclosed. The control strategy integrates various functions of engine control including fuel delivery, cooling fan control, engine speed governing and overspeed protection, engine braking, torque control, and vehicle speed diagnostics and control. Cooling fan control is integrated with vehicle speed diagnostics and control as well as fuel delivery to provide an integrated cruise control function which incorporates engine braking. The method also includes improved control over the various engine speed governors while improving idle quality by balancing the power delivered by each of the engine cylinders when at idle. The integrated torque control employs functions to reduce NOx emissions and noise utilizing adaptive fuel delivery timing and a split injection strategy.

Abstract: A method of compression braking is provided for use in an internal combustion engine having a plurality of combustion chambers that share a common exhaust manifold, such as, for example, a six-cylinder engine. The method comprises the steps of moving each exhaust valve to an open position at a first time corresponding to approximately the beginning of the power portion of the cycle of the combustion chamber associated with the exhaust valve and moving each exhaust valve to the open position at a second time corresponding to approximately the end of the intake portion of the cycle of the combustion chamber associated with the exhaust valve.

Abstract: An internal-combustion engine has an engine braking device which has brake valves by way of which the combustion chamber content of the cylinders can be diverted in the engine braking phase. In the engine braking operation, the brake valves are changed into the opening position. In order to increase the operational reliability of the engine braking device, a blocking device is provided which acts upon the brake valves and which can be adjusted between a holding position and a release position. In the holding position of the blocking device, the brake valves are held in the opening position.

Abstract: In a vehicle exhaust system, downstream end portions of front and rear exhaust pipes Ef, Er which respectively connect to front and rear cylinder banks are arranged side by side with each other in the same direction so as to be connected to a common collecting exhaust pipe 22, so that exhaust gases flowing through the front and rear exhaust pipes Ef, Er are allowed to flow into the common collecting exhaust pipe 22 in the same direction. Mating faces 15f, 20f are respectively formed on the end portions of the front and rear exhaust pipes Ef, Er which are located closer to the collecting portion, and the mating faces 15f, 20f are confronted from each other. The mating faces are inclined relative to a plane (P-P) passing through centers Ca, Cb of the front and rear exhaust pipes Ef, Er.

Abstract: A method and system for controlling the switching in of ancillary equipment driven by an engine of a vehicle, the ancillary equipment being arranged to be driven by the engine until at least a minimum operating level relating to the status of the ancillary equipment is attained.

Abstract: An engine exhaust braking method and apparatus. The method includes injecting a predetermined amount of fuel per stroke into an engine cylinder during engine braking, wherein the predetermined amount of fuel cools the fuel injector nozzle, thereby allowing the engine braking to be performed without damage to the fuel injector nozzle due to excessive heat. The apparatus includes a fuel injector having a nozzle and capable of injecting a predetermined amount of fuel into an engine, and a processor connected to the fuel injector, with the processor monitoring engine operation and capable of causing the fuel injector to inject the predetermined amount of fuel into the engine, wherein a predetermined amount of fuel is injected into the engine to cool the fuel injector nozzle, thereby allowing the exhaust braking to be performed without damaging the fuel injector nozzle due to excessive heat.

Abstract: The engine includes in at least one engine cylinder, an extra exhaust valve operated by a hydraulic plunger cylinder device. The engine has a fuel system with a unit injector, the cam and rocker arm of which also drive a pump arrangement, which has a pump chamber communicating with the low pressure side of the fuel system. The plunger of the plunger cylinder device is loaded by the pressure in the pump chamber. When a valve disposed in the communication between the fuel system and the pump chamber is closed, the fuel volume enclosed during the pump stroke will displace the plunger, opening the exhaust valve.

Abstract: In an engine braking operation for a supercharged internal-combustion engine which has an exhaust gas turbocharger having a turbine with a variable turbine geometry, the turbine geometry is adjusted between a ram position to reduce the effective turbine cross-section and an opening position to open the effective turbine cross-section. In order to influence the action of the engine brake simply, such that a braking is adapted to different situations, the variable turbine geometry is adjusted between a definable hard braking adjustment and a definable soft braking adjustment. The hard braking adjustment is situated between the ram position and a drive starting position assigned to the fired drive operating mode. The soft braking adjustment is situated between the drive starting position and the opening position. The hard braking adjustment is selected so that the engine braking power is higher than in the soft braking adjustment.

Abstract: An exhaust turbocharger for an internal combustion engine has a main compressor for compressing the fresh air supplied to the engine, an additional compressor for compressing combustion gases to be recycled to the engine, and a turbine that can be driven by the exhaust gases from the engine and which serves to drive the main compressor and the additional compressor. The turbine has an adjustable geometry which facilitates optimization of engine operation regarding pollutant emissions, fuel consumption, and performance.

Abstract: The present invention provides a method and apparatus for controlling an actuation of a compression brake associated with a combustion engine. The engine includes a fluid circuit for delivering a fluid to the compression brake. The engine also includes a cylinder having an associated exhaust valve. The method includes the steps of establishing a desired timing of an actuation of the brake, determining an air pressure of the engine, and determining a desired fluid pressure in response to the timing and the air pressure.

Abstract: There is provided an engine control apparatus with electromagnetically driven intake and exhaust valves which can widen the dynamic range of engine brake torque. The valve open timing of the electromagnetic exhaust valve during fuel cut is made to be variable between the initial stage of expansion stroke and the late stage thereof so as to control the magnitude of engine brake torque.

Abstract: A system for controlling camshaft timing, air/fuel ratio and electronic throttle position in an automotive internal combustion engine uses a controller for operating a camshaft phaser, electronic throttle positioner and fuel injectors. The controller determines camshaft timing, steady-state electronic throttle position, steady-state fuel supply, and compensatory transient electronic throttle position, and transient fuel supply such that an engine operating with the present system has the torque output characteristics matching a conventional engine having fixed camshaft timing, but with lower fuel consumption and lower exhaust emissions than a conventional engine.

Abstract: A compression engine braking system for an engine is disclosed having two exhaust valves 26a and 26b per cylinder, a crosshead 28 in contact with both exhaust valves 26a and 26b and a rocker 30 arranged in the drive train between an exhaust cam and the crosshead 28. One end of the rocker 30 acts on a point on the crosshead 28 lying between the exhaust valves 26a and 26b and the other end of the rocker is arranged to follow the surface of the exhaust cam. The braking system comprises a hydraulic primary piston 12 arranged in a hydraulic circuit 16 with a secondary cylinder 14 acting on one of the exhaust valves 26a. The primary cylinder is biased by a spring away from said other end of the rocker 30 when the compression brake is inactive and is biased by the pressure in the hydraulic circuit 16 to move with the other end of the rocker 30 when the compression brake is active. In the invention, a spring biased lash adjuster is arranged between the rocker 30 and the crosshead 28.

Abstract: In an internal combustion engine braking system which may provide compression release braking and/or exhaust braking, methods and systems are disclosed of controlling the overlap between an exhaust gas recirculation event and an intake valve event to optimize engine braking at various engine operating speeds. Optimization may be achieved by selectively advancing and retarding the opening and closing of an exhaust valve for exhaust gas recirculation. The opening and closing of the exhaust valve may be carried out responsive to the monitored levels of such engine parameters as: exhaust manifold pressure, exhaust manifold temperature, cylinder pressure, and/or cylinder temperature. Various engine parameters may be monitored. Control of exhaust gas recirculation may be responsive thereto, such that a monitored parameter does not exceed a predetermined level.

Abstract: A control method of an internal combustion engine with which braking force while reducing the speed of the motor vehicle can be established by generating pumping loss effectively by using a variable valve mechanism enabling to control arbitrarily the open-close timing and the lift amount of air intake and exhaust valves of the engine. When the break step-on force detection means detects a step-on force on a brake and an operation of the anti-lock brake system is selected, at least one of the intake valve or the exhaust valve is made close, another one not closed of the intake valve or the exhaust valve is made open once in a single revolution of the engine while a piston moves from a top dead center to a bottom dead center, and a lift of the valve is controlled to be a designated value.

Abstract: A variably timed internal combustion engine valve actuation system and method for opening valves in internal combustion engines. The system functions during both positive power and engine braking, to control the amount of "lost motion" between a valve and a means for opening the valve. In particular, the invention relates to a lost motion engine valve actuation system using a dedicated cam for effecting exhaust valve openings for compression release braking and exhaust gas recirculation ("EGR").

Abstract: A braking control for an engine permits the timing and duration of exhaust valve opening events to be accurately determined independent of engine events so that braking power can be precisely controlled. According to one embodiment, further control over braking power can be accomplished by controlling turbocharger geometry.

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). The valves can be controlled to produce an exhaust gas recirculation event during various operating modes of the engine.

Abstract: A method adjusts the engine braking performance of a supercharged internal-combustion engine. The exhaust gas turbocharger of the internal-combustion engine is provided with a variably adjustable turbine geometry for changing the effective turbine cross-section. In order to be able to transmit high brake powers, while the directional control is simultaneously high, a wheel slip control is implemented in the engine braking operation. The rotational speed of at least one wheel is measured and is compared with a reference value. In the event of a deviation of the measured rotational wheel speed from the reference value, a control signal is generated and fed to a control element which acts upon the variable turbine geometry for reducing the wheel slip.

Abstract: A system and method for reducing cab vibration during engine shutdown in a vehicle, including an internal combustion engine, an engine brake, and an electronic control unit for controlling the engine and the engine brake, includes logic for determining when a shutdown condition is occurring, and logic for generating a control signal to activate the engine brake during the engine shutdown. In one embodiment, the step of activating the engine brake is performed only after the engine speed has fallen below a pre-determined level. The system and method also preferably include automatically deactivating the engine brake at a pre-selected time, such as when engine RPM falls below a second threshold, to ensure that the engine brake is not activated upon restarting the engine.

Abstract: In a valve timing control for an engine having an electronic throttle control system, the response of a valve timing control mechanism is estimated by operating condition of the engine. In addition to controlling a relative rotation angle of the VVT, a throttle correction gain for correcting the opening angle of a throttle valve so as to be adapted to the response of the VVT is calculated. The throttle valve is controlled by the calculated gain. When the response of the VVT is slow, the opening angle of the throttle valve is corrected on the basis of the response. Thus, a rapid engine acceleration is suppressed, thereby preventing occurrence of misfire.

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: 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: In an internal combustion engine for motor vehicles with an engine shutdown driven capability, wherein the engine has intake and exhaust valves with a variable timing valve actuating system permitting the generation of an engine braking torque depending on the state of vehicle operation, the intake and exhaust valves are controlled during shutdown engine driven operation such that at least on type of valves, that is either all the intake or all the exhaust valves remain closed.

Abstract: A system for managing engine retarding torque during coast mode operation includes a control computer operable in one embodiment to control boost pressure, engine compression brake setting and/or engine accessory deactivation upon detection of coast mode operation with the engine compression brakes enabled. In another embodiment, the control computer is operable to determine a current engine retarding torque value, based either on an estimation thereof as a function of current boost pressure and engine compression brake setting or based on a mass estimation technique accounting for the grade of the road, and control boost pressure, engine compression brake operation and/or engine accessory deactivation to thereby control engine retarding torque upon detection of coast mode operation with the engine brakes enabled.

Abstract: The invention is a device consisting of a control module that allows a driver to electronically activate a truck's engine brakes. The brakes are activated by use of a push-button switch installed on the truck's gearshift lever. In the first embodiment of the invention, when the button is pressed and released, the control module's electronic circuitry keeps the engine brakes engaged until the clutch or throttle is used. In the second embodiment of the invention, the brakes also can be turned off by pressing the button again. The invention eliminates the need to use a truck's standard, dashboard-mounted manual switch to activate the engine brake and allows the driver to intermittently turn the engine brakes on or off.

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 retarder system for a vehicular drive train is disclosed. The retarder system includes a compression brake being adapted to operate in multiple stages to slow the speed of the engine and a fluid retarder being adapted to operate in multiple stages to absorb power from the drive train. A controller regulates the operational stages of the compression brake and the fluid retarder so that the compression brake and the fluid retarder operate in combination to slow the speed of the vehicle.

Abstract: A load driver system for integrally controlling the flow of current through a number of inductive loads of an internal combustion engine, particularly the flow of current through a fuel injector solenoid and an engine brake solenoid during the operation of an engine cylinder, is provided. In one embodiment of the load driver system, a single multiplexed high side driver is connected to inputs of both solenoids, and separate low side drivers are connected to outputs of each of the solenoids. In an alternative embodiment, separate high side drivers are connected to inputs of each of the solenoids, and a single multiplexed low side driver is connected to the outputs of the solenoids.

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: A compression braking system is provided which permits an engine's exhaust valves to be operated by fuel pressure during a braking mode independently of the engine's mechanical actuating elements and associated control limitations. The present braking system includes a high pressure fuel supply including a high pressure fuel accumulating device for accumulating and temporarily storing high pressure fuel and an actuator device including an actuator piston operatively connected to the engine exhaust valve and a brake actuating valve for controlling fuel flow from the accumulating device to the actuator piston. The pressure of the fuel acting on the actuator causes movement of the exhaust valve. The system may include a pressure regulator for decreasing the accumulator fuel pressure to a more appropriate actuation fuel pressure to minimize high pressure joints and leakage. A improved sealing means may be provided for preventing leakage around the actuator piston.

Abstract: An apparatus is provided for controlling a compression brake on an internal combustion engine. the apparatus includes means for automatically disabling the compression brake once the vehicle speed falls below a predetermined value.

Abstract: An internal combustion engine includes an intake valve for controlling a cylinder intake port; an exhaust valve for controlling a cylinder exhaust port; first and second valve lifters coupled to the intake and exhaust valves, respectively, for cyclically opening and closing the intake and exhaust valves during normal engine operation; and an actuating device for contacting the exhaust valve and for operating the exhaust valve independently from the second valve lifter. The actuating device has a withdrawn position and a valve-contacting position. In the withdrawn position the actuating device is out of contact with the exhaust valve and in the valve-contacting position the actuating device is in contact with the exhaust valve. There is further provided an electromagnetically-operating setting device having an inoperative position assumed for a normal engine operation and an operative position assumed for an engine-braking operation.

Abstract: A method of engine compression braking for an internal combustion engine is disclosed wherein the engine is converted to a two-cycle mode for braking. Exhaust valves are opened in cylinders wherein associated pistons are near top dead center and substantially simultaneously, exhaust valves are opened in cylinders wherein associated pistons are nominally past bottom dead center. The method results in an advantageous braking power increase due to back-filling of the cylinders wherein the pistons are nominally past bottom dead center. A similar method is disclosed for use during four-cycle braking.

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 injection system for an internal combustion engine having a plurality of cylinders is known which has a hydraulic pump with a delivery outlet to which a delivery line common to the cylinders is connected, and a plurality of injection units each of which is associated with a different cylinder and, in normal drive operation, can be controlled pulsewise by connection with the delivery line. There is also known an exhaust-brake system having a plurality of decompression valves each of which is associated with a different cylinder and, in brake operation, can be controlled pulsewise outside the exhaust stroke, in particular at the end of the compression stroke, by alternate pressure action on and pressure relief of the hydraulic actuating element. The purpose is to create a system with which, at little expense and at favorable cost, the "injection" and "exhaust-brake" functions can be satisfied.

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: The invention is based on a hydraulic system, in particular of an engine brake for an internal combustion engine, having at least one hydraulic actuating element, a positive displacement pump by which pressurized fluid can be pumped from a low-pressure region into a high-pressure region, and a distributor unit (14) having a control output (13) which is connected via a control line with the actuating element, which control output can be pressurized from the high-pressure region and connected to the low-pressure region. In order to obtain the desired control of the actuating elements over a wide range of cycle times and speeds of rotation of the internal combustion engine with a pump of relatively small displacement, a return valve which opens towards the high-pressure region is provided, via which the control line can be connected to the high-pressure region after it has been pressurized from the high-pressure region and before it is connected to the low-pressure region.

Abstract: A braking control for an engine permits the timing and duration of exhaust valve opening to be accurately determined independent of engine events so that braking power can be precisely controlled.

Abstract: In a decompression braking apparatus which is applicable to a Diesel engine and is capable of switching an engine braking condition so as to achieve an appropriate braking force depending upon an engine revolution speed area when a decompression braking request is issued, an eccentric bushing member is pivotally interposed between an inner periphery of a rocker arm and an outer periphery of a rocker shaft fitted into the rocker arm so as to be enabled to displace a swing center of the rocker arm to a first position at which a degree of openings in a closure stroke of an exhaust valve whose valve stem is linked to the rocker arm is relatively small and to a second position at which the degree of openings in the closure stroke thereof is relatively large and an actuator having a plunger linked to the eccentric bushing member hydraulically actuates the eccentric bushing member to pivot so that the swing center of the rocker arm is displaced to either of the first or second position depending on an engine revolut