An internal combustion engine has at least one combustion chamber and a piston slidably disposed within the at least one combustion chamber. The piston is configured to reciprocate between a top-dead-center position and a bottom-dead-center position. The internal combustion engine also has an air supply in selective fluid communication with the at least one combustion chamber and a fuel supply in selective fluid communication with the at least one combustion chamber. The internal combustion engine further has a supply of non-combustible gas and at least one injector in fluid communication with the at least one combustion chamber and the supply of non-combustible gas. The at least one injector is configured to inject non-combustible gas from the supply into the at least one combustion chamber.