Engine systems and methods for operating an engine

An engine system, comprising:

• an EGR system;
• a turbocharger having a turbine;
• and
• an internal combustion piston engine having a first cylinder in fluid communication with the EGR system through a first exhaust passage;
• a second cylinder in direct fluid communication with the turbine through a second exhaust passage;
• and a third cylinder in fluid communication with the turbine through a third exhaust passage, wherein the first exhaust passage, the second exhaust passage, and the third exhaust passage are in fluid isolation from each other and the first exhaust passage is in fluid isolation from the turbine, and further comprising a fourth cylinder and a fourth exhaust passage and the fourth cylinder is in fluid communication with the turbine through the fourth exhaust passage, wherein the first, second, third and fourth exhaust passages are in fluid isolation from each other and each of the second, third and fourth exhaust passages is connected to the turbine with respective ones of first, second and third inlet ports to the turbine, and each of the first, second and third inlet ports includes a wastegate.

A method of operating an engine, comprising:

• delivering exhaust gases from a first cylinder of an internal combustion engine as dedicated EGR cylinder to an EGR system through a first exhaust passage;
• delivering exhaust gases from a second cylinder of the internal combustion engine to a first inlet port of a turbine of a turbocharger through a second exhaust passage;
• delivering exhaust gases from a third cylinder of the internal combustion engine to a second inlet port of the turbine through a third exhaust passage;
• delivering exhaust gases from a fourth cylinder of the internal combustion engine to a third inlet port of the turbine through a fourth exhaust passage;
• and
• fluidly isolating the exhaust gases in the second exhaust passage from the exhaust gases in the third exhaust passage prior to entry into the turbine, fluidly isolating the exhaust gases in the first exhaust passage from the turbine, and fluidly isolating the exhaust gases in the first exhaust passage from the exhaust gases in the second and third exhaust passages, wherein the exhaust gases in the fourth exhaust passage are fluidly isolated from the exhaust gases in the first, second and third exhaust passages.