Stratified nitrogen enriched air (NEA) strategies and methods to reduce NOx emissions from engines

An engine system for injecting nitrogen into an internal combustion engine, comprising:

• a cylinder comprising a combustion chamber and a piston slidably positioned in the cylinder;
• a first intake line fluidly connected to the combustion chamber via a first intake port;
• one or more nitrogen injectors fluidly connecting a source of pure nitrogen to the combustion chamber;
• a fuel injector fluidly connecting a fuel source to the combustion chamber;
• wherein the one or more nitrogen injectors provide nitrogen to the combustion chamber to create a stratified gas environment with a high nitrogen concentration region and a low nitrogen concentration region within the combustion chamber.

An engine system for injecting nitrogen into an internal combustion engine, comprising:

• a cylinder comprising a combustion chamber and a piston slidably positioned in the cylinder;
• an intake line fluidly connected to the combustion chamber via an intake port;
• and
• a multi-nozzle injector connected to the cylinder, the multi-nozzle injector comprising:
• a fuel nozzle fluidly connecting a fuel source to the combustion chamber;
• and
• a nitrogen nozzle fluidly connecting a source of pure nitrogen to the combustion chamber.

An engine system for injecting nitrogen into an internal combustion engine, comprising:

• a cylinder comprising a combustion chamber and a piston slidably positioned in the cylinder;
• one or more nitrogen injectors fluidly connecting a source of pure nitrogen to a first and a second intake line;
• the first intake line fluidly connected to the combustion chamber via a first intake port configured to direct air with atmospheric concentrations of nitrogen to the combustion chamber;
• the second intake line fluidly connected to the combustion chamber via a second intake port configured to direct the pure nitrogen to the combustion chamber;
• and
• a fuel injector fluidly connecting a fuel source to the combustion chamber.