Electronically-controlled late cycle air injection to achieve simultaneous reduction of NOx and particulates emissions from a diesel engine

The present invention relates generally to reducing emissions from diesel engines and more specifically to electronically-controlled air injection to achieve simultaneous reduction of NOx and particulates emissions from a diesel engine. The invention provides an electronically-controlled air injection system for each cylinder of an internal combustion engine. The said engine has a piston in each cylinder, at least one exhaust valve of each cylinder, and a source of pressurized fuel. The injection system comprises at least one cylinder passage, a source of compressed air, an air solenoid connected to said source of compressed air and to said at least one cylinder, and a control unit connected to said air solenoid to thereby selectively supply supplemental air to said at least one cylinder passage.