Dual check fuel injector with single actuator

A fuel injector includes first and second check valve members that open and close first and second nozzle outlet sets, respectively, to inject two fuels that differ in at least one of chemical identity, pressure and molecular state. The first check valve member defines a through passage, includes a closing hydraulic surface exposed to fluid pressure in the first control chamber, and moves into and out of contact with a first seat on an injector body. The second check valve member includes a closing hydraulic surface exposed to fluid pressure in a second control chamber, and moves into and out of contact with a second seat located on the first check valve member. A control valve member is movable between first and second positions that respectively block and allow fluid communication between the first and second control chambers and a drain outlet.