A multi-mode power train and multi-mode vehicle include a power-conversion device that is in communication with an engine via a direct mechanical power-transfer connection extending from the engine to the power-conversion device. A continuously variable power source (CVP) is in communication with the power conversion device via an intermediate power-transfer connection. A lock-up device with first and second engagement states is provided between the engine and the power-conversion device or the CVP. With the lock-up device in the first engagement state, mechanical power from the engine is converted by the power-conversion device for use by the CVP, with the CVP using the converted power to provide mechanical power to a power-output connection. With the lock-up device in the second engagement state, the engine transmits mechanical power through the lock-up device to the power-output connection.

A multi-mode power train and multi-mode vehicle include a power-conversion device that is in communication with an engine via a direct mechanical power-transfer connection extending from the engine to the power-conversion device. A continuously variable power source (CVP) is in communication with the power conversion device via an intermediate power-transfer connection. A lock-up device with first and second engagement states is provided between the engine and the power-conversion device or the CVP. With the lock-up device in the first engagement state, mechanical power from the engine is converted by the power-conversion device for use by the CVP, with the CVP using the converted power to provide mechanical power to a power-output connection. With the lock-up device in the second engagement state, the engine transmits mechanical power through the lock-up device to the power-output connection.

An internal combustion engine has a chamber that has a longitudinal centerline, inlet valving operable to admit constituents of a combustible mixture into the chamber for combustion in the chamber to provide a pressure increase in the chamber and outlet valving operable to release an outflow of liquid from the chamber under an influence of the pressure increase. An annular flow passage is defined in the chamber to conduct liquid towards the outlet valving and cause spiraling of the liquid in the flow passage by which a rotatable part exposed to the spiraling flow is caused to rotate. An electrical generator disposed externally of the chamber is driven by rotation of the rotatable part.