Systems and methods for detecting and mitigating belt slip of an engine front end accessory drive are described. In one example, three different signals are input to a weighted average filter to determine the presence or absence of belt slip so that quality of an indication of belt slip may be improved.

The tensioning pulley arrangement for a belt drive in an engine, is provided. In one example, the tensioning pulley arrangement includes a first tensioning pulley and a second tensioning pulley tensioning a belt with a spring force and a spring preload force generated by a first spring device coupled to the first and second tensioning pulleys. The tensioning pulley arrangement further includes an intensifying device that decreases belt tension during low belt load conditions and increases belt tension during high belt load conditions. In this way, friction losses during low belt loads may be reduced and belt slippage caused by high belt loads and/or dynamic shifts in belt loads may also be reduced.

A variable belt tensioner for an engine includes: a first damper; and a second damper connected to the first damper through a driver. The first damper, the second damper, and the driver causes a belt connected to a crankshaft pulley and a starter-generator pulley to have a first tensile strength when the engine including the crankshaft pulley starts, the first damper, the second damper, and the driver causes the belt to have a second tensile strength that is less than the first tensile strength when an electric power is generated by the starter-generator pulley, and the first damper, the second damper, and the driver causes the belt to have a third tensile strength that is less than the second tensile strength when the vehicle is accelerated by the engine.

A work vehicle having an implement includes an engine control unit for controlling an engine and detecting an abnormal state of the engine, a PTO transmission mechanism for transmitting power from the engine to the implement, a PTO clutch for switching ON/OFF power transmission by the PTO transmission mechanism and a clutch control circuit configured to render the PTO clutch OFF based on a detection signal outputted by the engine control unit at time of detection of the abnormal state.

The disclosure relates to a method for detecting belt slip of a belt drive driving a generator of an internal combustion engine, said belt drive having a belt tensioner that can be adjusted in operation and adjusts the pre-tensioning force of the belt according to the detected belt slip. According to said method, the rotational speed profile of the crankshaft is recorded during an angular window of the crankshaft of m.Math.360 degrees and an average value of the crankshaft rotational speed is formed from said rotational speed profile; temporally independently from the recording of the rotational speed profile of the crankshaft, the rotational speed course of the generator shaft is recorded during an angular window of the generator shaft of n.Math.u.sup.1.Math.360 degrees and an average value of the generator shaft rotational speed is formed from said rotational speed profile.

A vehicle includes a chain tensioner that serves as an oil damper using oil supplied from an oil pump. The vehicle includes a controller that controls a traveling mode of the vehicle in a BEV mode or a non-BEV mode. When shifting the traveling mode from the BEV mode to the non-BEV mode, the controller executes a high-pressure process for controlling the oil pump such that a supply pressure of oil supplied to the chain tensioner becomes higher when a duration of the BEV mode is greater than or equal to a specified time than when the BEV mode duration is less than the specified time.

A belt slip monitor system and method configured to determine whether a belt coupled to a motor-generator is slipping based on operational states of first and second movable portions of the belt slip monitor, wherein the operational states of the first and second movable portions are dependent upon the tension in the belt.

In an aspect, a tensioner includes a pulley, a main piston chamber, a reservoir, and first and second fluid passageways connecting the main piston chamber and reservoir, a main piston that is movable in the main piston chamber, a check valve, a control valve, and a movable reservoir member. The check valve prevents flow in one direction through the second passageway and permits flow in an opposing direction through the second passageway. The control valve is movable between to provide a first flow resistance, or a second flow resistance. The movable reservoir member is movable based on the amount of fluid in the reservoir in such a way as to change the volume of the reservoir, such that the reservoir, the main piston chamber and the first and second passageways together are included in a fluid circuit that is substantially free of any compressible fluids.

Methods and systems are provided for tensioning a belt of a belt drive of an internal combustion engine. In one example, a movable tensioning means assigned to an active tensioner is provided, which applies a force to a belt of a belt drive, and the active tensioner is controlled such that a compression of a spring of the tensioner is at least countered, so that a movement of the tensioning means under the load of the belt is at least hindered. The belt is then excited to vibration in a contact zone between the belt and the movable tensioning means by use of a starter so that the tensioning means exposed to the force of the spring is moved further in the direction of the belt under expansion of the spring, whereby the belt is tensioned.

A method for starting an internal combustion engine using a starter generator to which the engine is connected via a belt drive, the belt drive including a belt pulley of the starter generator, a belt pulley of the internal combustion engine, and a belt connecting the belt pulleys in a torque-transmitting manner, includes operating the starter generator such that its drive torque output to the belt pulley of the starter generator is according to a drive torque curve by which an output torque generated temporarily on the belt pulley of the internal combustion engine exceeds the drive torque of the starter generator, taking a gear ratio of the belt drive into consideration.