A variety of methods and arrangements for reducing noise, vibration and harshness (NVH) in a skip fire engine control system are described. In one aspect, a firing sequence is used to operate the engine in a skip fire manner. A smoothing torque is determined that is applied to a powertrain by an energy storage/release device. The smoothing torque is arranged to at least partially cancel out variation in torque generated by the skip fire firing sequence. Various methods, powertrain controllers, arrangements and computer software related to the above operations are also described.

A variety of methods and arrangements for reducing noise, vibration and harshness (NVH) in a skip fire engine control system are described. In one aspect, a firing sequence is used to operate the engine in a skip fire manner. A smoothing torque is determined that is applied to a powertrain by an energy storage/release device. The smoothing torque is arranged to at least partially cancel out variation in torque generated by the skip fire firing sequence. Various methods, powertrain controllers, arrangements and computer software related to the above operations are also described.

An active vibration reduction control apparatus for a hybrid electric vehicle includes: a reference signal generator generating a reference signal and a first phase based on a first rotational angle of a first motor; a vibration extractor extracting a vibration signal from a second motor; a coefficient determiner determining a filter coefficient which minimizes a phase difference between the reference signal and the vibration signal; a phase determiner detecting a second phase which corresponds to the phase difference using a first speed signal of the first motor and the filter coefficient; a phase deviation amount detector detecting a third phase for compensating for a phase delay; and a synchronization signal generator generating an antiphase signal of a shape of an actual vibration in order to determine a compensating force of the first motor.

An active vibration reduction control apparatus for a hybrid electric vehicle includes: a reference signal generator generating a reference signal and a first phase based on a first rotational angle of a first motor; a vibration extractor extracting a vibration signal from a second motor; a coefficient determiner determining a filter coefficient which minimizes a phase difference between the reference signal and the vibration signal; a phase determiner detecting a second phase which corresponds to the phase difference using a first speed signal of the first motor and the filter coefficient; a phase deviation amount detector detecting a third phase for compensating for a phase delay; and a synchronization signal generator generating an antiphase signal of a shape of an actual vibration in order to determine a compensating force of the first motor.

A control apparatus for a vehicle that includes a power transmission apparatus including a frictional engagement element configured to connect and disconnect transmission of a power between a drive power source and drive wheels of the vehicle. The control apparatus is configured to execute a vibration suppression control for estimating torsional vibration of the power transmission apparatus, based on a preformulated vibration model, and controlling a torque of a rotating machine that is connected to the power transmission apparatus, so as to suppress the torsional vibration. The control apparatus allows execution of the vibration suppression control, when the frictional engagement element is in an engaged state, and also when a differential rotation of the frictional engagement element has become smaller than a predetermined determination value even with the frictional engagement element being in a disengaged state.

A control apparatus for a vehicle that includes a power transmission apparatus including a frictional engagement element configured to connect and disconnect transmission of a power between a drive power source and drive wheels of the vehicle. The control apparatus is configured to execute a vibration suppression control for estimating torsional vibration of the power transmission apparatus, based on a preformulated vibration model, and controlling a torque of a rotating machine that is connected to the power transmission apparatus, so as to suppress the torsional vibration. The control apparatus allows execution of the vibration suppression control, when the frictional engagement element is in an engaged state, and also when a differential rotation of the frictional engagement element has become smaller than a predetermined determination value even with the frictional engagement element being in a disengaged state.

A control device of a hybrid vehicle includes a pressing torque applying portion configured to control the first rotating machine to output a pressing torque acting in a predetermined backlash elimination direction in backlash elimination in which one of tooth surfaces of meshing gears is pressed against the other at a meshing portion during motor running, so that the pressing torque is applied on the electric transmission mechanism. When an electrical angle of the first rotating machine is within a predetermined electrical angle range in which a cogging torque of the first rotating machine generated in accordance with rotation of the first rotating machine is equal to or greater than a predetermined torque required for the backlash elimination in the predetermined backlash elimination direction, the pressing torque applying portion makes the pressing torque smaller as compared to when the electrical angle is outside the predetermined electrical angle range.

A method for determining a longitudinal tire stiffness (K.sub.x) for at least one wheel on a motor vehicle while the motor vehicle is in operation, may include generating a sinusoidal modulation of an axle drive torque or wheel drive torque necessary for maintaining the current vehicle speed (ν), or a braking torque or recuperation torque necessary for maintaining the current braking power in at least one wheel for a sinusoidal excitation of a wheel rotational rate (ω), such that a sinusoidal oscillation in the wheel rotational rate is induced. The method may also include detecting the resulting sinusoidal oscillation in the wheel rotational rate, determining the amplitude (ω.sub.amp) of the oscillation in the wheel rotational rate induced, and determining longitudinal tire stiffness (K.sub.x) from the amplitude (ω.sub.amp). A corresponding apparatus for carrying out the method may be included.

A method for determining a longitudinal tire stiffness (K.sub.x) for at least one wheel on a motor vehicle while the motor vehicle is in operation, may include generating a sinusoidal modulation of an axle drive torque or wheel drive torque necessary for maintaining the current vehicle speed (ν), or a braking torque or recuperation torque necessary for maintaining the current braking power in at least one wheel for a sinusoidal excitation of a wheel rotational rate (ω), such that a sinusoidal oscillation in the wheel rotational rate is induced. The method may also include detecting the resulting sinusoidal oscillation in the wheel rotational rate, determining the amplitude (ω.sub.amp) of the oscillation in the wheel rotational rate induced, and determining longitudinal tire stiffness (K.sub.x) from the amplitude (ω.sub.amp). A corresponding apparatus for carrying out the method may be included.

A control apparatus for a hybrid electrically-operated vehicle that includes an engine, a rotating machine, a transmission apparatus and an engine connection/disconnection device which is to be engaged to connect a power transmission between the engine and the transmission apparatus and which is to be released to disconnect the power transmission between the engine and the transmission apparatus. The control apparatus executes a vibration suppression control by using a first vibration model in which the engine connection/disconnection device is engaged and a second vibration model in which the engine connection/disconnection device is released, such that the vibration suppression control is executed also during a switch control for switching between an engine driving mode and a motor driving mode, by using one of the first and second vibration models which is used in execution of the vibration suppression control before start of the execution of the switch control.