Energy recovery system for large motor vehicles

An energy recovery system for a wheeled vehicle having an internal combustion engine connected through a transmission to a vehicle drive train for transmitting torque to and from the wheels thereof, wherein the heat in exhaust gases in the exhaust line form the internal combustion engine is recovered using a Rankine cycle with a working fluid and braking energy is recovered by compressing and expanding the working fluid, comprising:

• (a) a compressor/expander connected with the vehicle drive train via a lock-up clutch such that when the compressor/expander is operated as an expander in a run mode it assists the engine in driving the vehicle and when operated as a compressor in the braking mode it stores braking energy, said compressor/expander having inlet and outlet ports;
• (b) a heat exchanger connected with the engine for receiving the vehicle exhaust gases and for transferring heat from the exhaust gases to a working fluid in order to generate high-pressure vapor;
• (c) a boiler drum connected with said heat exchanger for storing the heated and vaporized working fluid and for supplying high-pressure vapor to the inlet port of the compressor/expander during run mode;
• (d) a flash chamber connected with said boiler drum for supplying low-pressure steam to the inlet port of the compressor/expander during the braking mode;
• and
• (e) storage means into which the lower-pressure vapor is compressed during the braking mode and from which it is passed to the input of the compressor/expander during the run mode.