Mid-Cycle Fuel Injection Strategies

A method for introducing a gaseous fuel into a combustion chamber of an internal combustion engine comprising:

• (b) introducing said gaseous fuel into said combustion chamber during an intake stroke in a first region of an engine map associated with operating said internal combustion engine;
• (c) introducing said gaseous fuel into said combustion chamber during a compression stroke in a second region of said engine map after an intake valve associated with said combustion chamber closes;
• and
• (d) introducing said gaseous fuel into said combustion chamber during both said intake stroke and said compression stroke in a third region of said engine map, wherein said first region is a low load region of said engine map, said second region is a high load region of said engine map below at least one of a predetermined power level and a predetermined speed, and said third region is a high load region of said engine map above said at least one of said predetermined power level and said predetermined speed.

An apparatus for introducing a gaseous fuel into a combustion chamber of an internal combustion engine comprising:

• (a) a fuel injection apparatus for introducing said gaseous fuel into a charge for said internal combustion engine, said fuel injection apparatus comprising:
• (i) a direct fuel injector for injecting said gaseous fuel directly into said combustion chamber;
• (ii) a controller programmed to actuate said fuel injection apparatus according to three modes, to:
• (1) introduce gaseous fuel into said charge during an intake stroke while an intake valve associated with said combustion chamber is open, when said internal combustion engine is operating in a first mode, defined by a predetermined low load range;
• (2) actuate said direct fuel injector to inject said gaseous fuel directly into said combustion chamber after said intake valve is closed, when said internal combustion engine is operating in a second mode, defined by a predetermined high load low-speed range;
• and
• (3) split fuel injection into two pulses whereby a first portion of said gaseous fuel is introduced into said charge during an intake stroke while said intake valve is open, and a second portion is introduced by actuating said direct fuel injection to inject said fuel directly into said combustion chamber after said intake valve is closed, when said internal combustion engine is operating in a third mode defined by a predetermined high load high-speed range.