Abstract: A method and a system for reducing belt noise in an engine, wherein the belt is engaged with an alternator includes a transmission upshift detection module determining a transmission upshift or a quickly closing throttle detection module determining a quickly closing throttle. The control module further includes an engine speed prediction module determining a predicted engine speed in response to determining a transmission upshift and an engine deceleration prediction module determining a predicted engine deceleration when the predicted deceleration of the engine crankshaft is greater than a threshold. An alternator control module controls a rotor current in the alternator to add load to the alternator rotor to reduce potential belt noise.

Abstract: A method for controlling, during temporary stoppage, a four-stroke combustion engine including a block delimiting cylinders which define combustion chambers equipped with pistons into which opens an intake pipe and an exhaust pipe, both provided with valves that can move between open and closed positions. The method involves detecting conditions of a temporary stoppage of the engine and commanding the exhaust valves to be kept in the closed position once the engine has gone through an intake phase during the last engine cycle prior to the stoppage.

Abstract: In the calibration of a lambda sensor (26), inaccuracies occur during a fuel cut-off overrun phase depending on the temperature. A method is proposed for correcting an output signal of a lambda sensor (16) of an internal combustion engine (1), having the following steps: detection of a fuel cut-off overrun phase of the internal combustion engine (1), sensing of an exhaust-gas composition by the lambda sensor (16) during the fuel cut-off overrun phase, sensing of a temperature which represents a measure of the intake air of the internal combustion engine (1), calibration of the lambda sensor (16) based on the second temperature.

Abstract: A lost motion valve actuation system includes an engine brake housing and one or more hydraulic fluid supply passages extending through the housing. Master and slave pistons are slidably disposed corresponding bores in the housing. The master and slave pistons are used to provide selective actuation to one or more engine valves. An engine brake rocker arm disposed adjacent to the housing includes a master piston contact surface and a bias mechanism contact surface. A bias mechanism is disposed in the housing and includes a bias piston which extends from the housing. The bias piston biases the rocker arm out of contact with an engine cam during select engine operation modes, such as during a positive power mode of operation. The bias piston may be mechanically or hydraulically repositioned to permit the rocker arm to contact the engine cam during a second mode of engine operation, such as an engine braking mode.

Abstract: A control system for an engine includes a stop-start initiation module and a load control module. The stop-start initiation module shuts down the engine in response to an engine shutdown request. The load control module, in response to the engine shutdown request, increases a rate at which a rotational speed of the engine decreases during engine shutdown by increasing a rotational load input to the engine by an engine accessory coupled to a crankshaft of the engine. A method for an engine includes shutting down the engine in response to an engine shutdown request. The method further includes increasing, in response to the engine shutdown request, a rate at which a rotational speed of the engine decreases during engine shutdown by increasing a rotational load input to the engine by an engine accessory coupled to a crankshaft of the engine.

Abstract: A system to prevent engine stalls for a machine having a power source is disclosed. The power source is in communication with a controller, which is configured to determine the temperature of the power source and compare the temperature of the power source to a predetermined threshold temperature. The controller is configured to disable power source braking if the temperature of the power source is less than the threshold temperature. The controller is further configured to determine the power source speed and the travel speed of the machine, and disable power source braking if the power source speed and machine travel speed are less than predetermined thresholds.

Abstract: A method and a device for operating an internal combustion engine are provided which make it possible to implement different deceleration requests to the internal combustion engine by switching over between half engine operation and full engine operation. A deceleration request is received particularly in a nonoperating state. A switchover is made between a first operating state and a second operating state of the internal combustion engine as a function of the magnitude of the deceleration request. The first operating state and the second operating state differ, in this instance, in the number of cylinders whose charge changing process is interrupted.

Abstract: A control system for engine braking for a vehicle powered by a turbocharged engine uses a supercharger to assist a turbocharger compressor to boost turbocharger air flow into the engine cylinders. An engine driven air pumping device draws ambient air, or alternately exhaust gas through the pump inlet, compresses the air, and delivers the compressed air through the pump outlet to the turbocharger compressor inlet or alternately the turbocharger compressor outlet. The increased air flow into the cylinders and out of the cylinder exhaust valves increases retarding power of the vehicle.

Abstract: A device and a method for evaluating a sensor signal indicating the position of an accelerator pedal of a motor vehicle. For this purpose, the device compares the sensor signal to a first comparison level, and an idle state is ascertained if the first comparison level is undershot. When a start of the motor vehicle from rest is detected, a departure from the idle state is inferred if a second comparison level, which is lower than the first comparison level, is exceeded.

Abstract: A system to prevent engine stalls for a machine having a power source is disclosed. The power source is in communication with a controller, which is configured to determine the temperature of the power source and compare the temperature of the power source to a predetermined threshold temperature. The controller is configured to disable power source braking if the temperature of the power source is less than the threshold temperature. The controller is further configured to determine the power source speed and the travel speed of the machine, and disable power source braking if the power source speed and machine travel speed are less than predetermined thresholds.

Abstract: A method for controlling stopping and starting of an engine having a variable event valvetrain is described. According to the method engine valves may be used to reduce engine evaporative emissions as well as engine starting emissions. Since the engine configuration shown has electrically actuated intake and exhaust valves it is possible to reconfigure the engine operating sequence during a start. For example, the pistons for cylinders two and three are in the same position at the same time. This allows either cylinder to be set to an intake stroke during a subsequent engine restart when the piston is traveling away from the cylinder head while the companion cylinder is set to the expansion or power stroke. Thus, the cylinder having the first intake stroke could be configured to provide a first combustion event during an engine restart.

Abstract: In an engine ECU (60), a threshold line LS1 and a threshold line LS2 are set as threshold lines used when stopping of an engine is prohibited based on a coolant temperature Tw. The threshold line LS1 is set to ensure a predetermined heating capacity. The threshold value on the threshold line LS2 is higher than the threshold value on the threshold line LS1. When the vehicle is moving, the threshold line LS2 is selected to prohibit/permit stopping of the engine. This increases the amount of heat stored in an engine coolant. When the vehicle is stopped, the threshold line LS1 is selected to prohibit/permit stopping of the engine. This decreases the frequency of starting the engine in the stopped vehicle, while maintaining the predetermined heating capacity.

Abstract: The present disclosure is directed to a method of retarding an engine. The method includes selectively retarding the engine in a first mode configured to produce a first level of retarding at a first intensity of noise by selectively opening at least one exhaust valve between ninety degrees and zero degrees of an engine crank angle prior to top-dead-center of a compression stroke. The method also includes selectively retarding the engine in a second retarding mode configured to produce a second level of retarding at a second intensity of noise by maintaining an opening of at least one exhaust valve throughout the entire compression stroke.

Abstract: An integrated type engine brake for a diesel engine includes: a cam cap; a valve integral with the cam cap, the valve including an oil inlet and an oil outlet; and a rocker shaft with a brake oil passage in fluid communication with the oil inlet and the oil outlet. The cam cap also has a brake oil passage in fluid communication with the oil inlet and the oil outlet. The brake oil passages of the cam cap and the rocker shaft are in direct fluid communication with one another.

Abstract: A leisure vehicle equipped with an internal combustion engine as a power unit to drive the leisure vehicle, including a drive wheel, a slip sensor unit configured to detect a slip of the drive wheel, a throttle device mounted to the internal combustion engine, a throttle valve position changing device configured to change a position of a throttle valve of the throttle device, a throttle close operation sensor unit configured to detect that a rider has performed a throttle close operation to close a throttle of the throttle device, and a controller configured to control an operation of the throttle valve position changing device.

Abstract: A vehicle control apparatus includes a first fuel-cut duration extending portion that, when a fuel-cut is being executed during deceleration of the vehicle, slows the decrease in the engine speed by executing a slip control of a lock-up clutch; and a second fuel-cut duration extending portion which, when the engine speed has decreased to a coast-downshift threshold, which is higher by a given amount than a fuel-cut cancellation threshold, while the slip control is being executed, allows to downshift the automatic transmission if the road on which the vehicle is presently traveling has a downhill gradient that is larger than a reference value.

Abstract: A newly obtained wheel speed of a drive wheel is not used in a calculation for acceleration slip when a vehicle is stopped, for example, when the wheel speed of a rolling wheel is zero and an engine speed is high. A wheel speed calculated before a previous wheel speed is, for example, set as a current wheel speed. In this manner, even if the wheel speed of a driving wheel is due to the effect of racing noise, it is possible to limit erroneous determinations that indicate acceleration slip is being generated, based upon such a wheel speed. In addition, unnecessary execution of a traction control can also be curbed.

Abstract: Internal combustion engine and method with compression and expansion chambers of variable volume, a combustion chamber, a variable intake valve for controlling air intake to the compression chamber, a variable outlet valve for controlling communication between the compression chamber and the combustion chamber, means for introducing fuel into the combustion chamber to form a mixture of fuel and air which burns and expands in the combustion chamber, a variable inlet valve for controlling communication between the combustion chamber and the expansion chamber, a variable exhaust valve for controlling exhaust flow from the expansion chamber, means for monitoring temperature and pressure conditions, and a computer responsive to the temperature and pressure conditions for controlling opening and closing of the valves and introduction of fuel into to the combustion chamber to optimize engine efficiency over a wide range of engine load conditions.

Abstract: In an internal combustion engine having cylinders connected by means of controllable brake valves to a common gas pressure container which is in communication, by way of an outflow line with an outflow valve, with the exhaust strand of the internal combustion engine, an inlet gas pressure container is connected to the intake tract of the internal combustion engine and is in communication with the common pressure container by means of a recirculation line having a controllable check valve arranged therein permitting the establishment of various engine operating and control features.

Abstract: A method for operating at least an intake and exhaust valve in a cylinder with a piston of an engine in a vehicle, comprising during conditions of an engine shut-down, maintaining at least one of the intake and exhaust valves in a closed position, and during conditions where said at least one valve is in said closed position operating with the other of the intake and exhaust valve open, then closing the other of the intake and exhaust valve, and then opening the other of the intake and exhaust valve to generate braking torque to slow the engine.

Abstract: A system and method for controlling a variable valve actuation system for an engine is provided. An engine valve is moved between a first position where the engine valve blocks a flow of fluid and a second position where the engine valve allows a flow of fluid. Fluid is provided to a chamber of a valve actuator adapted to operatively engage the engine valve. A parameter indicative of a viscosity of the fluid provided to the chamber of the valve actuator is sensed. Fluid is trapped within the chamber of the valve actuator to prevent the engine valve from moving to the first position. A response time of the valve actuator is determined based on the viscosity of the fluid provided to the chamber of the valve actuator. The response time indicates the time required to release the fluid from the chamber of the valve actuator to allow the engine valve to move to the first position.

Abstract: A method of controlling a variable valve actuation system is provided. A cam assembly is operated to move an intake valve between a first position where the intake valve blocks a flow of fluid and a second position where the intake valve allows a flow of fluid. At least one operating parameter of the engine is sensed. A valve actuation period is determined based on the at least one operating parameter. A valve actuator is engaged with the intake valve to prevent the intake valve from returning to the first position in response to operation of the cam assembly. The valve actuator is released to allow the intake valve to return to the first position at the end of the determined valve actuation period.

Abstract: An engine valve actuation system is provided. An intake valve is moveable between a first position where the intake valve prevents a flow of fluid relative to the intake valve and a second position where the intake valve allows a flow of fluid relative to the intake valve. A cam assembly is configured to move the intake valve between the first position and the second position. A fluid actuator having a chamber is adapted to selectively prevent the intake valve from moving to the first position. A fluid supply system is adapted to deliver fluid to the chamber of the fluid actuator. A pressure sensor is operatively engaged with the fluid supply system and is adapted to sense the pressure of the fluid within the fluid supply system.

Abstract: Low load operating point for a controlled auto-ignition four-stroke internal combustion engine is reduced without compromising combustion stability through a valve control operative to establish sub-atmospheric pressure conditions within the combustion chamber into which fuel and exhaust gases are introduced.

Abstract: A system for modifying or disabling a selected engine function in response to a determination based upon a precipitation sensor input that precipitation is present. The system also may include an ambient temperature sensor that determines whether the ambient temperature is below a predetermined level. Signals from the precipitation sensor and temperature sensor are provided to an engine controller. The engine controller functions to modify or disable a selected engine function such as a compression brake, engine exhaust brake, maximum speed calibration or passing speed variance calibration.

Abstract: A method for operating an internal combustion engine (10) installed in a motor vehicle having controlled intake and exhaust valves and that is coupled in fixed fashion with an electrical machine (16) charging an electrical energy accumulator, in particular a battery (21), wherein, in order to enable the electrical machine to perform recuperation on overrun or during braking operation of the internal combustion engine (10), the drag power or braking power of the internal combustion engine is regulated via intervention in the valve actuation process so that a braking or deceleration behavior of the motor vehicle is obtained that is familiar to the driver of the motor vehicle, wherein the valve actuation process and a regulation of the generator and motor operation of the electrical machine (16) are carried out as a function of the state of charge, preferably of at least four levels of the state of charge, of the energy accumulator (21), and wherein the valve actuation process and the regulation of the electrica

Abstract: Engine compression release brakes include some degree of lash between the brake actuation portion and the engine exhaust valve portion. The disclosed apparatus and method provides an integral lash adjuster that includes an adjusting screw that is threadably received by a slidable plunger. Rotation of the adjusting screw causes the plunger to slide relative to a plunger cavity and responsively modify the amount of lash.

Abstract: An engine deceleration control system for an internal combustion engine of a vehicle is arranged to prohibit correcting an air quantity supplied to the engine when an elapsed time period from a moment of turning off of an accelerator of the engine is within a first predetermined time period, or when an elapsed time period from a moment of turning off of a lockup clutch of a torque converter is within a second predetermined time period or when a shifting of a transmission connected to the engine is being executed, and to cancel prohibiting the correction of the supplied air quantity when a braking operation is executed.

Abstract: A method of controlling an engine is provided. At least one operating parameter of the engine is sensed. The engine is operated in a first mode in response to the sensed operating parameter being at one of a predetermined first set of conditions. In the first mode, a cam assembly moves an intake valve from a first position when a piston starts an intake stroke and the cam assembly returns the intake valve to the first position when the piston completes the intake stroke. The engine is operated in a second mode in response to the sensed operating parameter being at one of a predetermined second set of conditions. In the second mode, the cam assembly moves the intake valve from the first position when the piston starts an intake stroke and an actuator prevents the intake valve from returning to the first position in response to the cam assembly.

Abstract: A vehicle-mounted internal combustion engine has a variable lift mechanism for varying the valve lift of an intake valve. During deceleration of the vehicle, an ECU performs fuel cutoff control for temporarily stopping supply of fuel to the engine. During the fuel cutoff control, the ECU performs throttle opening increase control as necessary to set the opening degree of a throttle valve greater than a usual target opening degree that is set when an acceleration pedal is not depressed. If the throttle opening increase control is being performed when resumption of the fuel supply is required during the fuel cutoff control, the ECU controls the variable lift mechanism such that the valve lift is reduced compared to a situation where the throttle opening increase control is not being performed.

Abstract: A compression release brake system 10 includes a hydraulic apparatus 12 for controllably opening at least one exhaust valve 14 of at least one cylinder 16 of an engine in response to motion of a cam actuator 12. The system 10 includes a master piston assembly 40 having a master piston 42 engageable with the cam actuator 12. The master piston 42 includes a compressible piston pin 56. A slave piston assembly 44 is hydraulically linked to the master piston assembly 40 and includes a slave piston 46 engageable with the at least one exhaust valve 14.

Abstract: A method and system of automatically controlling engine speed of a vehicle in a turn employs an engine control system (10) to determine an optimal engine speed for the turn and an actual engine speed as sensed by an engine speed sensor (38). Engine control system (10) determines the difference between optimal engine speed and actual engine speed and compares this difference to current engine load. Based on this comparison, engine control system (10) then determines whether to alter engine speed and, if so, determines an amount to reduce the difference between optimal engine speed and actual engine speed.

Abstract: An engine valve actuation system is provided. The system includes an engine valve moveable between a closed position and an open position. A spring is operatively connected to the engine valve to bias the engine valve towards the closed position. An actuator is operatively connected to the engine valve and is operable to selectively engage the engine valve to prevent the engine valve from returning to the closed position and to release the engine valve to allow the engine valve to return to the closed position. A sensor is configured to provide information related to the operation of the actuator. A controller is configured to transmit a signal to the actuator to engage the engine valve to prevent the engine valve from returning to the closed position and to release the engine valve to the allow the engine valve to return to the closed position.

Abstract: An engine (10) having a control system (24) that executes a control strategy (44) for limiting engine fueling upon deactivation of an engine retarder. Upon deactivation of the retarder, the strategy immediately shuts off fueling by setting the maximum fueling limit MFLMX to zero via setting of a latch function (42). Fueling continues to be shut off so long as the difference between a desired pressure for the hydraulic fluid used to force fuel into the engine combustion chambers and actual pressure of the hydraulic fluid (ICP_ERR) equals or exceeds a value (ICP_VRE_ERR) from a map (48) correlated both with the speed (N) at which the engine is running and with governed engine fueling (MFGOV) appropriate for the load on the engine at the engine running speed. Once that difference ceases to equal or exceed a value from the map (48), the latch function is reset, and the limit value for fueling provided by the strategy increases withtime according to a map (54).

Abstract: A method and an arrangement for operating a drive motor of a vehicle are suggested. A resulting desired torque for controlling the drive motor is pregiven in dependence upon the driver command torque and additional desired torque quantities. To limit the resulting desired torque, a motor minimum torque is provided which is derived from the lost torques and is dependent upon rpm.

Abstract: A method and an arrangement control the drive unit of a vehicle. In this method and arrangement, an rpm limiting to a reference rpm takes place when the demand of the driver is withdrawn. The reference rpm is determined at the start of the withdrawal of the driver command.

Abstract: Method and arrangement for engine breaking in motor vehicles having an internal combustion engine with at least one cylinder, at least one exhaust valve at the cylinder and a rocker arm (4) for activation of the exhaust valve. The rocker arm (4) is arranged on a hollow rocker arm shaft (5) and arranged to be effected by ridges (2a, 2b, 2c) on a camshaft (2), the device additionally having a control valve (15, 16) for controlling the oil pressure in the rocker arm shaft (5), and means (6; 14) receptive to an increase of the oil pressure in the rocker arm shaft (5) being integrated in the rocker arm (4) for absorbing a play between the rocker arm (4) and the exhaust valve in the case of increase oil pressure. At least one of the ridges (2b, 2c) causes opening of the exhaust valve with an engine breaking effect.

Abstract: A control strategy for mitigation of the effect of increased engine back-pressure on fuel injectors (22) when an engine retarder is activated to slow the engine (10) of a motor vehicle. The strategy attenuates injection control pressure ICP of hydraulic fluid for the fuel injectors to a defined dwell pressure ICP_VRE_DWL, and once that dwell pressure has been attained, keeps the injection control pressure from exceeding it for the length of a dwell time ICP_DWL_TM. Upon elapse of the dwell time, the injection control pressure gradually increases above the dwell pressure using a pressure versus time map (54). When engine operating conditions call for greater injection control pressure while the retarder is activated, the strategy provides for greater injection control pressure using a pressure versus speed map (42).

Abstract: A method of calibrating a variable valve actuation system is provided. An engine valve is moved from a first position where the engine valve blocks a flow of fluid to a second position where the engine valve passes a flow of fluid. A valve actuator is actuated to prevent the engine valve from returning to the first position. A signal is transmitted to cause the valve actuator and to allow the engine valve to return to the first position. The return of the engine valve to the first position is determined. A time parameter indicative of an elapsed time between the transmission of the signal and movement of the engine valve to the first position is determined.

Abstract: An engine brake for a supercharged internal combustion engine for driving a motor vehicle is operated such that the working gas compressed during engine braking, prior to the end of the expansion cycle, is drawn at least partially from the working chambers of the engine through at least one throttle valve, with an exhaust turbocharger of the engine having an exhaust turbine with variable turbine geometry. The engine braking power is regulated based upon the travel of the throttle valve and/or an intake cross section of the exhaust turbine as a function of the operating parameters of the internal combustion engine and the vehicle driving speed. Upon issuance of a signal indicating a braking performance requirement from the driver, the required braking power is applied at least preferably through the engine brake.

Abstract: A fuel injector is provided which has an injector body with a metallic tip having an outer surface. A non-metallic insulator, such as a ceramic, is attached to the tip and covers a portion of the outer surface. Injector tip overheating can be a problem, especially during sustained two-cycle boosted engine compression release braking. In addition, injector tip overheating can be a problem when an engine is experiencing simultaneous engine compression release braking and exhaust braking.

Abstract: The invention relates to a multicylinder internal combustion engine with an engine braking system including intake and exhaust valves and at least one additional brake valve for each cylinder, the exhaust valves opening into an exhaust system. Further a preferably tubular pressure reservoir with a pressure regulating valve is provided, into which braking channels departing from the brake valves are leading, so that a gas exchange between the individual cylinders is possible upon actuation of the brake valves.

Abstract: An actuator for adjusting a clearance between an end of a valve and an end of the actuator. The actuator has a piston therein having a central bore of which a portion is threaded. The piston has an end and has a flat defined near the end. The actuator has a stem member positioned therein. The stem member has a central portion which is threadedly positioned within the threaded portion of the central bore. The stem member defines a first end and a second end, and a threaded portion is located near the second end. The first end of the stem member and the end of the piston has a predetermined length which is adjustable. The predetermined length is adjusted by threadedly rotating the stem member relative to the piston. A locking device fixes the predetermined length during operation of the engine.

Abstract: In a process for automatic adjustment of handling of a motor vehicle having an internal-combustion engine, operating and condition quantities are determined and compared with reference values. If the operating and condition quantities deviate from the reference values, adjusting signals are generated for adjusting vehicle and engine components. In order to recognize predetermined driving situations, and to make corresponding adjustments for influencing the vehicle handling, starting and ending of predetermined driving modes (acceleration operation, deceleration operation and constant drive operation) are detected by logically evaluating diverse operating and condition quantities. The conditions for detecting the start of a driving condition differ from the conditions for the end of the same driving condition.

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: The invention is directed to a method and an arrangement for controlling the rpm of a drive unit. During run-up of the engine to idle after start, a desired rpm is pregiven and an actual rpm is detected for forming the course of rpm. An electric machine is driven in dependence upon the deviation between the desired rpm and the actual rpm. With respect to the engine, the electric machine outputs braking and driving torques.

Abstract: The present invention is directed to a control value 20 which incorporates the functions of both a shuttle valve and a check valve into a single structure for use in a lost motion engine brake system. In response to a supply of hydraulic fluid from switched low pressure supply circuit 320, control valve body 200 of control value 20 may index within control valve bore 204, such that hydraulic fluid flows through upper annulus 260, first horizontal bore 270, first vertical bore 280, middle annulus 261 and out through lashless fluid supply circuit 340 and accumulator control circuit 350 to acuate engine valve 100. In an embodiment for clipping/rest of the valve actuating piston 130, clipping/reset spool 450 provided in rocker shaft 405. In response to rotational or linear motion, spool annuluses 451 on clipping/reset spool 450 move to open and close clipping reset/passageway 455 and accumulator control circuit 350, thereby providing clipping of piston 130.

Abstract: A valve control apparatus is provided for an internal combustion engine having a valve and a camshaft. The camshaft has an axis of rotation, a first lobe and a second lobe adjacent to the first lobe. The second lobe is angularly spaced-apart about the axis from the first lobe. The apparatus includes a follower operatively engagable with the camshaft and the valve. The follower has a first operational mode where the first lobe operatively engages the follower on each revolution of the camshaft to open the valve a first time on each revolution. There is a mechanism for selectively putting the follower in a second operational mode where the second lobe operatively engages the follower to open the valve a second time on each revolution of the camshaft. The mechanism puts the follower in the second operational mode on each revolution of the camshaft before the second lobe is fully aligned with the follower.

Abstract: A drive unit includes a hydrodynamic retarder having a rotor paddle wheel, a stator paddle wheel, and a housing surrounding the rotor and stator wheels. The unit includes a coolant cycle system for an internal combustion engine, the coolant for this coolant cycle also being a working medium of the retarder. The drive unit further includes a working medium container for the coolant which is connected to the coolant cycle system. A connecting pipe is disposed between the working medium container and a hydrodynamic center of the retarder. A valve is disposed in the connecting pipe.

Abstract: The invention relates to a system and method for engine braking a four-stroke internal combustion engine. The engine has for each cylinder at least one inlet valve and at least one exhaust valve for controlling communication between a combustion chamber in the cylinder and an inlet system and an exhaust system, respectively. In addition, each cylinder communicates with an independent high pressure transfer passage via individual transfer valves disposed at each cylinder. The transfer valves, respectively, put each cylinder at the early part of its compression stroke in communication with the high pressure transfer passage that has been filled with high pressure air by another cylinder at the later part of its compression stroke. Opening the exhaust valve to further decompress the cylinder nearing the end of its compression stroke preferably follows this process.