A transmission for an energy storage and recovery system comprises a variable slip transmission and a clutch arranged to transmit drive while slipping. The level of torque transmitted through the slipping clutch is dependent on the clutch force but is independent of the clutch slip speed. Preferably the clutch is provided by a plurality of clutches connected in parallel in a range extender. When drive is transferred between clutches in parallel, the clutch forces of both clutches are controlled to maintain the total torque transmitted by the clutches. This reduces torque fluctuations at the energy source/sink during clutch transfer. Where there are two slipping clutches in series, one clutch is controlled to provide the required torque and the other clutch is controlled in response to a clutch slip speed. This helps to control the speed of rotation of the mass between the clutches.

A transmission for an energy storage and recovery system comprises a variable slip transmission and a clutch arranged to transmit drive while slipping. The level of torque transmitted through the slipping clutch is dependent on the clutch force but is independent of the clutch slip speed. Preferably the clutch is provided by a plurality of clutches connected in parallel in a range extender. When drive is transferred between clutches in parallel, the clutch forces of both clutches are controlled to maintain the total torque transmitted by the clutches. This reduces torque fluctuations at the energy source/sink during clutch transfer. Where there are two slipping clutches in series, one clutch is controlled to provide the required torque and the other clutch is controlled in response to a clutch slip speed. This helps to control the speed of rotation of the mass between the clutches.

A transmission for an energy storage and recovery system is disclosed. A variable slip transmission and a clutch arranged to transmit drive while slipping. The level of torque transmitted through the slipping clutch is dependent on the clutch force but is independent of the clutch slip speed. Preferably the clutch is provided by a plurality of clutches connected in parallel in a range extender. When drive is transferred between clutches in parallel, the clutch forces of both clutches are controlled to maintain the total torque transmitted by the clutches. This reduces torque fluctuations at the energy source/sink during clutch transfer. Where there are two slipping clutches in series, one clutch is controlled to provide the required torque and the other clutch is controlled in response to a clutch slip speed. This helps to control the speed of rotation of the mass between the clutches.

A power transmission apparatus for a hybrid vehicle may include a planetary gear set as a torque branching device disposed on the same axis with the engine; and a final reduction device having a final reduction gear receiving a torque of the engine and a torque of the second motor/generator, wherein, the torque of the engine is delivered to the final reduction gear through the planetary gear set, an intermediate shaft, and an output gear formed on an output shaft, and the torque of the second motor/generator is delivered to the final reduction gear through a shifting device facilitating multi-stages of torque transmission.

A power transmission apparatus for a hybrid vehicle may include a planetary gear set as a torque branching device disposed on the same axis with the engine; and a final reduction device having a final reduction gear receiving a torque of the engine and a torque of the second motor/generator, wherein, the torque of the engine is delivered to the final reduction gear through the planetary gear set, an intermediate shaft, and an output gear formed on an output shaft, and the torque of the second motor/generator is delivered to the final reduction gear through a shifting device facilitating multi-stages of torque transmission.

A transmission for an energy storage and recovery system is disclosed. A variable slip transmission and a clutch arranged to transmit drive while slipping. The level of torque transmitted through the slipping clutch is dependent on the clutch force but is independent of the clutch slip speed. Preferably the clutch is provided by a plurality of clutches connected in parallel in a range extender. When drive is transferred between clutches in parallel, the clutch forces of both clutches are controlled to maintain the total torque transmitted by the clutches. This reduces torque fluctuations at the energy source/sink during clutch transfer. Where there are two slipping clutches in series, one clutch is controlled to provide the required torque and the other clutch is controlled in response to a clutch slip speed. This helps to control the speed of rotation of the mass between the clutches.

A system for operating a dual clutch transmission, including launch/creep controller, shift logic, and a clutch control assembly. The shift logic is configured to intercept a torque command including a target clutch torque from the launch/creep controller as it transmits the target clutch torque to the clutch assembly. The shift logic engages a preparation phase that increases torque on an on-coming clutch to a prefill torque. The shift logic then engages a torque phase that transfers torque between the off-going clutch and the on-coming clutch by simultaneously decreasing the off-going clutch torque and increasing the on-coming clutch torque. The off-going clutch and the on-coming clutch remain in a slipping state that maintains the target clutch torque during the transfer.