Post injections during cold operation

An exhaust gas heating system of a direct injection compression ignition internal combustion engine having a plurality of combustion chambers and an exhaust passage, comprising:

• means for determining whether activation of the exhaust treatment device is required based on at least one temperature related engine operating parameter, and if required,
• means for providing to at least one direct fuel injection device a fuel injection signal including a post fuel injection signal for producing a post fuel injection during a cylinder cycle of a corresponding one of the plurality of combustion chambers, whereby combustion of fuel injected in response to the fuel injection signal provides a predetermined quantity of heated exhaust gas for increasing exhaust treatment device efficiency;
• and
• means for dynamically determining at least one parameter of the post fuel injection signal provided to the at least one direct fuel injection device based on the at least one temperature related engine operating parameter, such that the post fuel injection does not produce substantial mechanical energy.

A computer program product including a computer readable medium containing instructions for, controlling a fuel injection control system of a direct injection compression ignition internal combustion engine having a plurality of combustion chambers and an exhaust passage and a governor, for use with an exhaust gas heating system, the instructions comprising the steps of:

• determining whether activation of an exhaust treatment device is required based on at least one temperature related engine operating parameter, and if required,
• providing to at least one direct fuel injection device a fuel injection signal including a post fuel injection signal for producing a post fuel injection during a cylinder cycle of a corresponding one of the plurality of combustion chambers, whereby combustion of fuel injected in response to the fuel injection signal provides a predetermined quantity of heated exhaust gas for increasing exhaust treatment device efficiency;
• and
• dynamically determining at least one parameter of the post fuel injection signal provided to the at least one direct fuel injection device based on the at least one temperature related engine operating parameter, such that the post fuel injection does not produce substantial mechanical energy.