Abstract: An Organic Rankine Cycle (ORC) Waste Heat Recovery (WHR) System has an LT working fluid loop and an HT working fluid loop. The working fluid loops may each have a pump, one or more heat exchanger boilers, an expander, and a condenser. A recuperator is arranged within the LT working fluid loop between the pump and the first heat exchanger boiler. The recuperator is also arranged within the HT working fluid loop between the expander and the pump, or within the LT working fluid loop between the expander and the condenser. One of the heat exchanger boilers in the LT loop may be a charge air cooler heat exchanger, and may receive charge air mixed with recirculating exhaust gas. The LT loop may include more than one heat exchanger boiler, arranged in series or in parallel. Bypass valves may selectively bypass one or more of the heat exchangers.

Abstract: While an engine (10, 10A, 10B, 10C, 10D, 10E) is operating, a control system (22) processes data for certain engine operating parameters to calculate a quantity of exhaust gas needed to satisfy an exhaust gas recirculation requirement. If a primary EGR control loop (34) alone can satisfy the calculated quantity of exhaust gas, a secondary EGR control loop (36) is closed while the primary EGR control loop is controlled to satisfy the calculated quantity. When the processing determines that the primary EGR control loop alone cannot satisfy the calculated quantity, the secondary EGR control loop is open concurrently with the primary EGR control loop and both the primary EGR loop and the secondary EGR loop are controlled to cause the combined flow of exhaust gas through the primary EGR control loop and flow of exhaust gas through the secondary EGR control loop to satisfy the calculated quantity.

Abstract: While an engine (10, 10A, 10B, 10C, 10D, 10E) is operating, a control system (22) processes data for certain engine operating parameters to calculate a quantity of exhaust gas needed to satisfy an exhaust gas recirculation requirement. If a primary EGR control loop (34) alone can satisfy the calculated quantity of exhaust gas, a secondary EGR control loop (36) is closed while the primary EGR control loop is controlled to satisfy the calculated quantity. When the processing determines that the primary EGR control loop alone cannot satisfy the calculated quantity, the secondary EGR control loop is open concurrently with the primary EGR control loop and both the primary EGR loop and the secondary EGR loop are controlled to cause the combined flow of exhaust gas through the primary EGR control loop and flow of exhaust gas through the secondary EGR control loop to satisfy the calculated quantity.