Intensifier apparatus and method for supplying high pressure gaseous fuel to an internal combustion engine

An apparatus for supplying high pressure gaseous fuel to a fuel injector of an internal combustion engine, said apparatus comprising:

• (a) a fuel storage vessel;
• (b) an intensifier having a first compression chamber with a first piston therein, and a second compression chamber with a second piston therein;
• (c) an accumulator vessel for holding a quantity of gaseous fuel at an injection pressure within a pre-determined acceptable operating range;
• and,
• (d) a plurality of fuel lines for directing flow of said gaseous fuel from said storage vessel to said accumulator vessel and for providing direct connections between said fuel storage vessel, said intensifier, and said accumulator vessel, said fuel passages including:
• (i) a first fuel line for connecting an outlet from said fuel storage vessel to a first inlet to said first compression chamber;
• (ii) a second fuel line for connecting a first outlet from said first compression chamber to a second inlet to said second compression chamber;
• (iii) a third fuel line for connecting a second outlet from said second compression chamber to an inlet to said accumulator vessel;
• (iv) a first closeable by-pass passage, connecting the first fuel line with the second fuel line;
• and
• (v) a second closeable by-pass passage, connecting the fuel line with the third fuel line.