Multi-stage intensifiers adapted for pressurized fluid injectors

A fluid injector having a multistage intensifier comprising:

• an injector adapted to inject fluid responsive to the pressurization of an injection fluid;
• a fluid injection pump piston adapted to pressurize injection fluid when moved in a first direction;
• a first intensifier piston positioned to apply force to the fluid injection pump piston in the first direction responsive to the pressure of an actuating fluid against an effective area of the first intensifier piston;
• a second intensifier piston positioned to apply force to the fluid injection pump piston in the first direction responsive to the pressure of an actuating fluid against an effective area of the second intensifier piston;
• and,
• a control valve coupled to selectively apply actuating fluid pressure to any of:
• i) the effective area of the first intensifier piston,
• ii) the effective area of the second intensifier piston, and
• iii) the effective area of both the first and second intensifier pistons.

A method of operating a fuel injector having a multi-stage intensifier, comprising:

• providing a fuel injection pumping piston adapted to pressurize injection fuel when hydraulically moved in a first direction;
• providing a first effective area of the multi-stage intensifier responsive to an actuating fluid pressure to move the injection fuel pumping piston in the first direction;
• providing a second effective area of the multi-stage intensifier responsive to an actuating fluid pressure to move the injection fuel pumping piston in the first direction, the first and second effective areas being unequal areas;
• selectively providing actuating fluid under pressure to the first effective area or the second effective area or simultaneously providing actuating fluid under pressure to the first and second effective areas to selectively pressurize injection fuel by the injection fuel pumping piston.