Gaseous fuel mixer and shutoff valve

A mixing device for introducing gaseous fuel into an intake passage of an engine, the mixing device comprising:

• a body through which the intake passage extends for directing the intake airflow into the engine;
• an annular channel defined within the body to at least partially encircle the intake passage, wherein the body defines a fuel inlet opening intersecting with a radially outer portion of the annular channel;
• a plurality of gaseous fuel injectors arranged to discharge gaseous fuel into a fuel inlet manifold;
• a fuel connection passage extending between the fuel inlet manifold and the fuel inlet opening of the body and configured to receive all of the gaseous fuel discharged from all of the plurality of gaseous fuel injectors;
• a diffuser positioned within the body, wherein the diffuser is positioned along the intake passage at a position of the annular channel to diffuse gaseous fuel from the annular channel into the intake airflow in the intake passage;
• and
• a valve positioned along the fuel connection passage and configured to selectively block fluid communication between the fuel inlet manifold and the fuel inlet opening of the body in response to an electrical signal from at least one electronic controller programmed to execute control strategies controlling operation of the engine, the plurality of gaseous fuel injectors, and the valve.