Air-compressing fuel-injection internal-combustion engine with an exhaust treatment device for reduction of nitrogen oxides

An air compressing fuel-injection type internal combustion engine arrangement comprising:

• a variable volume combustion chamber which provides for engine operating cycles with compression, ignition, expansion and exhaust of a fuel and air mixture supplied to the combustion chamber,
• an exhaust treatment device for supplying reducing agents to reduce nitrogen oxides in the exhaust from the combustion chamber,
• a temperature sensor for sensing the temperature in the region of the exhaust treatment device, to thereby control operation of the exhaust treatment device, and
• a fuel injection system including a high pressure pump and a fuel injection nozzle opening to the combustion chamber, said fuel injection system providing for primary fuel injection through the fuel injection nozzle to the combustion chamber during a first stage of the engine operating cycle to facilitate primary combustion in said combustion chamber and providing for secondary fuel injection to the combustion chamber during a second stage of the engine operating cycle to affect the effectiveness of the exhaust treatment device,
• wherein said secondary fuel injection is provided as a supplementary fuel injection by way of the same fuel injection nozzle as the primary fuel injection and spaced by a time interval from the primary fuel injection with the supplementary fuel injection occurring at the earliest toward the end of the combustion phase after ignition top dead center in the combustion chamber, and
• wherein the supplementary injection is merely an exhaust temperature-increasing early supplementary injection, which commences directly after the starting of the engine in the region between 20.degree. and 80.degree. after ignition top dead center operation and can be switched off at a predetermined time.

A method of operating an air-compressing fuel-injection type internal combustion engine arrangement comprising:

• a variable volume combustion chamber which provides for engine operating cycles with compression, ignition, expansion and exhaust of a fuel and air mixture supplied to the combustion chamber,
• an exhaust treatment device for supplying reducing agents to reduce nitrogen oxides in the exhaust from the combustion chamber,
• a temperature sensor for sensing the temperature in the region of the exhaust treatment device, to thereby control operation of the exhaust treatment device, and
• a fuel injection system including a high pressure pump and a fuel injection nozzle opening to the combustion chamber,
• said method comprising providing for primary fuel injection through the fuel injection nozzle to the combustion chamber during a first stage of the engine operating cycle to facilitate primary combustion in said combustion chamber and providing for secondary fuel injection to the combustion chamber during a second stage of the engine operating cycle to affect the effectiveness of the exhaust treatment device,
• wherein said secondary fuel injection is provided as a supplementary fuel injection by way of the same fuel injection nozzle as the primary fuel injection and spaced by a time interval from the primary fuel injection with the supplementary fuel injection occurring at the earliest toward the end of the combustion phase after ignition top dead center in the combustion chamber,
• and wherein the supplementary injection which follows the primary injection with a time interval within an operating cycle, is merely a nitrogen oxide reducing late supplementary injection, which takes place between 80.degree. after ignition top dead center and the bottom dead center operation of the combustion chamber.

A method of operating an air-compressing fuel-injection type internal combustion engine arrangement comprising:

• a variable volume combustion chamber which provides for engine operating cycles with compression, ignition, expansion and exhaust of a fuel and air mixture supplied to the combustion chamber,
• an exhaust treatment device for supplying reducing agents to reduce nitrogen oxides in the exhaust from the combustion chamber,
• a temperature sensor for sensing the temperature in the region of the exhaust treatment device, to thereby control operation of the exhaust treatment device, and
• a fuel injection system including a high pressure pump and a fuel injection nozzle opening to the combustion chamber,
• said method comprising providing for primary fuel injection through the fuel injection nozzle to the combustion chamber during a first stage of the engine operating cycle to facilitate primary combustion in said combustion chamber and providing for secondary fuel injection to the combustion chamber during a second stage of the engine operating cycle to affect the effectiveness of the exhaust treatment device,
• wherein said secondary fuel injection is provided as a supplementary fuel injection by way of the same fuel injection nozzle as the primary fuel injection and spaced by a time interval from the primary fuel injection with the supplementary fuel injection occurring at the earliest toward the end of the combustion phase after ignition top dead center in the combustion chamber,
• and wherein the supplementary injection is merely an exhaust temperature-increasing early supplementary injection, which commences directly after the starting of the engine in the region between 20.degree. and 80.degree. after ignition top dead center operation and can be switched off at a predetermined time.