Full agnostic compression ignition engine

A compression ignition engine, comprising:

• an engine cylinder, the engine cylinder comprising:
• an inner surface;
• a head surface;
• a piston disposed and configured to move in the engine cylinder;
• an intake valve;
• and
• an exhaust valve, the inner surface of the engine cylinder, the piston, the head surface, the intake valve, and the exhaust valve defining a combustion chamber having a compression ratio of at least about 15:1;
• a fuel supply configured to contain a fuel, the fuel having a cetane number of less than about 40 and an octane number of at least 95, the fuel including less than about 500 ppm by weight of additives that affect cetane number;
• a fuel injector fluidically coupled to the fuel supply and configured to deliver a volume of the fuel from the fuel supply to the combustion chamber;
• and
• a thermal management system configured to limit a delay between initiation of injection of the volume of fuel into the combustion chamber and ignition of the volume of fuel to no more than about 2 ms when at least about 25% of the energy generated from combusting the volume of the fuel is generated while the volume of fuel is injected into the combustion chamber.

A compression ignition engine, comprising:

• an engine cylinder, the engine cylinder comprising:
• an inner surface;
• a head surface;
• a piston disposed and configured to move in the engine cylinder;
• an intake valve;
• and
• an exhaust valve, the inner surface of the engine cylinder, the piston, the head surface, the intake valve, and the exhaust valve defining a combustion chamber having a compression ratio of at least about 15:1;
• a fuel supply configured to contain a fuel, the fuel having a cetane number of less than about 40 and an octane number of at least 95;
• a fuel injector fluidically coupled to the fuel supply and configured to deliver a volume of the fuel from the fuel supply to the combustion chamber;
• and
• a thermal management system configured to modify a temperature of intake air to limit a delay between initiation of injection of the volume of fuel into the combustion chamber and ignition of the volume of fuel to no more than about 2 ms when no more than about 50% of the volume of the fuel is pre-mixed with air upon initiation of combustion and at least about 25% of the energy generated from combusting the volume of the fuel is generated while the volume of fuel is injected into the combustion chamber.