Apparatus and method for regulating and injecting gaseous fuel into an internal combustion engine

An apparatus for regulating and injecting a first gaseous fuel or a second gaseous fuel in an internal combustion engine comprising:

• a pressure regulator for regulating a pressure of the first gaseous fuel or a pressure of the second gaseous fuel;
• an in-cylinder fuel injector in fluid communication with the pressure regulator to receive the first gaseous fuel or the second gaseous fuel for directly injecting the first gaseous fuel or the second gaseous fuel into a combustion chamber of the internal combustion engine;
• and
• a controller operatively connected with the pressure regulator and the in-cylinder fuel injector and programmed to:
• when fueling the internal combustion engine with the first gaseous fuel:
• command the pressure regulator to regulate the pressure of the first gaseous fuel to a first injection pressure at an engine load and an engine speed;
• and
• command the in-cylinder fuel injector to inject within 90 crank angle degrees of top dead center during a compression stroke of the engine an injected quantity of the first gaseous fuel into the combustion chamber at the first injection pressure;
• and
• when fueling the internal combustion engine with the second gaseous fuel:
• command the pressure regulator to regulate the pressure of the second gaseous fuel to a second injection pressure at the engine load and the engine speed;
• and
• command the in-cylinder fuel injector to inject within 90 crank angle degrees of top dead center during the compression stroke of the engine an injected quantity of the second gaseous fuel into the combustion chamber at the second injection pressure;
• wherein the first gaseous fuel comprises less mole percent hydrogen than the second gaseous fuel;
• the second injection pressure is less than the first injection pressure at the engine load and the engine speed by a pressure value;
• and
• the injected quantity of the first gaseous fuel and the injected quantity of the second gaseous fuel burn in a diffusion combustion mode.