Active method for cold start emissions reduction

A system of reducing engine cold start emissions, comprising:

• an internal combustion engine system, comprising:
• an engine chamber with a piston;
• one or more of the following, configured to enable a negative valve overlap (NVO) mode of operation in which an intake valve opening (IVO) timing is later than an exhaust valve closing (EVC) timing:
• a continuously variable valve duration (CVVD) mechanism for both an intake valve and an exhaust valve;
• a dual CVVD and continuously variable valve timing (CVVT) mechanism for both the intake valve and the exhaust valve;
• and
• a cam system;
• a fuel delivery system comprising one or more of the following:
• a direct injector;
• and
• a port fuel injector;
• and
• an ignition system;
• and
• a computing device, comprising a processor and a memory, configured to store programming instructions that, when executed by the processor, cause the processor to:
• perform the NVO mode of operation, with an NVO during a gas exchange top dead center, to trap hot burnt gas in a cylinder and increase overall gas temperature for improved fuel vaporization before a fuel-air mixture is burnt;
• and
• perform one or more of:
• a double fuel injection with a first fuel injection and a second fuel injection being performed during the NVO mode of operation;
• a double fuel injection with the first injection taking place during the NVO mode of operation and the second fuel injection taking place after an intake valve opening (IVO) timing is later than the EVC timing;
• and
• a triple fuel injection, with the first fuel injection taking place during the NVO mode of operation, the second fuel injection taking place before firing Top Dead Center (TDCf), and the third fuel injection taking place after TDCf.