Patent ID: 6910333

Claim:
A Rankine cycle system for an internal combustion engine, comprising a first Rankine cycle ( 2 A) operated by a first working medium and a second Rankine cycle ( 2 B) operated by a second working medium, each of the Rankine cycles ( 2 A and 2 B) being comprised of an evaporator ( 3 A, 3 B) for heating a liquid-phase working medium by waste heat from the internal combustion engine ( 1 ) to generate a vapor, an expander ( 4 ) for converting the heat energy of the vapor discharged by said evaporator ( 3 A, 3 B) into a mechanical energy, a condenser ( 5 A, 5 B) for cooling the vapor discharged by said expander ( 4 ) to return the vapor into the liquid-phase working medium, and a supply pump ( 6 A, 6 B) for supplying the water discharged by said condenser ( 5 A, 5 B) to said evaporator ( 3 A, 3 B), wherein said evaporator ( 3 A) in said first Rankine cycle ( 2 A) and said evaporator ( 3 B) in said second Rankine cycle ( 2 B) are respectively disposed at locations upstream and downstream of an exhaust emission control device ( 8 ) mounted in an exhaust passage ( 7 ) for the internal combustion engine ( 1 ); said first working medium is of a boiling point higher than that of said second working medium; and the capacity of said supply pump ( 6 A) in at least said first Rankine cycle ( 2 A) is variable.