Method to increase temperature in an exhaust aftertreatment device coupled to a camless engine
AssigneeFord Global Technologies, LLC
InventorDiana D. Brehob
Life of this patent
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Abstract
A system and method are disclosed for operating an internal combustion to provide a temperature rise in an exhaust aftertreatment device. An exhaust valve is actuated during a compression stroke to release unburned fuel and air. The fuel oxidizes with the air in the exhaust aftertreatment device causing an exotherm. The opening and closing time of the exhaust valve are determined to cause the desired amount of fuel and air to be released into the exhaust aftertreatment device.
Claims17
A method for operating a multi-cylinder internal combustion engine, each cylinder is coupled to an exhaust aftertreatment device via an exhaust valve capable of actuation during a compression stroke of the cylinder, comprising the steps of:
- providing a predetermined amount of air and a predetermined amount of fuel into one of the cylinders of the engine;
- compressing said air and said fuel during the compression stroke of the cylinder;
- and
- opening the exhaust valve prior to ignition of said air and said fuel and during said compressing step, said exhaust valve opening releasing a portion of said air and a portion of said fuel into the exhaust aftertreatment device to raise its temperature.
A method for operating a multi-cylinder internal combustion engine, each cylinder is coupled to an exhaust aftertreatment device via an exhaust valve capable of actuation during a compression stroke of the cylinder, comprising the steps of:
- providing a predetermined amount of a mixture of fuel and air into a cylinder of the engine;
- compressing said mixture;
- opening the exhaust valve during said compressing step, said exhaust valve opening releases a portion of said mixture into the exhaust aftertreatment device to raise its temperature;
- and
- closing the exhaust valve after said opening step and prior to igniting a retained mixture, said retained mixture is said predetermined amount of said mixture less said released portion of said mixture.
A system for providing fuel and air to an exhaust aftertreatment device coupled to a reciprocating multi-cylinder internal combustion engine, comprising:
- an exhaust valve coupled to a cylinder of the engine which is capable of being actuated during a compression stroke of the cylinder;
- an engine controller operably connected to the engine and said exhaust valve to actuate said exhaust valve during said compression stroke thereby releasing a portion of the contents of said cylinder into the exhaust aftertreatment device;
- and
- an intake valve coupled to said cylinder, wherein said actuation of said exhaust valve occurs after said intake valve is closed and before the contents of said cylinder are ignited.
A computer readable storage medium having stored data representing instructions executable by a computer to control a multi-cylinder internal combustion engine, each cylinder has at least one intake valve, at least one exhaust valve and a piston disposed therein, each cylinder is coupled to an exhaust aftertreatment device via the exhaust valve, comprising:
- instructions to determine a retained amount of air and fuel to trap in one of the cylinders;
- and
- instructions to determine a bypass amount of air and fuel to release from the cylinder into the exhaust aftertreatment device, said release occurs during a compression stroke, said compression stroke comprises an upward movement of the piston while the intake and the exhaust valves are closed.
Dependencies are inferred from the claim text.