NOVELTY - The assembly (10) has an energy storage mechanism for storing energy recovered from an exhaust manifold (14) by a downstream exhaust turbine (16). An engine control unit (ECU) (19) varies rate of storing energy in the storage mechanism. An electrical generator (18) converts mechanical power from the turbine to electrical power. The ECU varies voltage demanded by the generator, which varies the rate of storing energy and light vehicle load of the turbine and back pressure created. The ECU controls output power of an engine by manipulating the back pressure of the engine via the turbine.    USE - Engine assembly for use in a hybrid vehicle (claimed) i.e. hybrid passenger car. Can also be used for a highway commercial vehicle e.g. refuge truck or off highway vehicle such as quarry dump truck.    ADVANTAGE - The assembly allows better package freedom. The assembly removes alternator altogether, and has no front end accessory drive (FEAD), thus improving fuel economy and cost vs benefit equation as the assembly captures kinetic energy rather than energy that can drive the vehicle. The assembly allows an electrical machine and the turbine to run at same speed without major compromise, thus reducing need for reduction gears between units. The assembly reduces size of an energy storage device on hybrid as the hybrid can be used more readily compared to certain known hybrids. The assembly sets a vane position to optimize efficiency for a particular engine running condition or globally to maximize benefit of a pulse and cruise running mode if the turbine is a variable geometry unit. The assembly allows VGT at position to be matched to the speed, thus maximizing the energy recovered, and hence setting an efficient operating point for a given electrical output and achieving optimum performance among engine efficiency, turbine efficiency and electrical machine efficiency.    DETAILED DESCRIPTION - The storage mechanism is selected from a group consisting of a battery, capacitor and a flywheel. An INDEPENDENT CLAIM is also included for a hybrid vehicle.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of an engine assembly.    Engine assembly (10)    Exhaust manifold (14)    Downstream exhaust turbine (16)    Electrical generator (18)    ECU (19)    Variable geometry turbocharger (20)    Intercooler (22)    Air-filter (24)