Engine idle warm-up of a homogeneous charge compression ignition engine
AssigneeGM Global Technology Operations LLC
InventorsTang-Wei Kuo, Paul M. Najt
Life of this patent
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Abstract
A homogeneous charge compression ignition engine is fueled within a warm-up region of engine temperatures using a minimally defined fuel mass schedule and injection timings and simple interpolative techniques.
Claims11
A method of operating an internal combustion engine in a four-stroke combustion cycle, said engine including a direct-injection fuel system, a spark-ignition system, and a variable volume combustion chamber defined by a piston reciprocating within a cylinder between top-dead center and bottom-dead center points, intake and exhaust passages, and intake and exhaust valves controlled during repetitive, sequential exhaust, intake, compression and expansion strokes of said piston, said method comprising:
- determining engine temperature within a predefined warm-up temperature region of engine operation, said warm-up temperature region including predefined non-overlapping low, middle and high temperature regions of engine operation;
- controlling intake and exhaust valves within said warm-up temperature region of engine operation to effect a partial-lift, negative valve overlap of about 180 to about 200 crank angle degrees;
- and
- in said low temperature region of engine operation, injecting a low temperature region predetermined total fuel mass comprising a low temperature region first injection terminating at about 350 to about 360 crank angle degrees before top dead center combustion and a low temperature region second injection terminating at about 270 to about 300 crank angle degrees before top dead center combustion;
- in said middle temperature region of engine operation, injecting a middle temperature region predetermined total fuel mass comprising a middle temperature region first injection terminating at about 270 to about 300 crank angle degrees before top dead center combustion;
- and
- in said high temperature region of engine operation, injecting a high temperature region predetermined total fuel mass comprising a high temperature region first injection terminating at about 370 to about 440 crank angle degrees before top dead center combustion and a high temperature region second injection terminating at about 25 to about 50 crank angle degrees before top dead center combustion.
An apparatus for controlling a direct-injection, spark ignition, internal combustion engine within a spark-assisted homogeneous-charge, compression-ignition range during engine warm-up at idle conditions, comprising:
- a control system monitoring engine temperature and effecting control of an engine warm-up procedure comprising
- intake and exhaust valve control to effect a partial-lift, negative valve overlap of about 180 to about 200 crank angle degrees,
- fuel mass injection according to an idle warm-up stable combustion minimum fuel mass delivery schedule, said schedule comprising:
- a low temperature fuel mass value in a low temperature region;
- a middle temperature fuel mass value in a middle temperature region,
- a high temperature fuel mass value in a high temperature region, and
- interpolated minimum fuel mass delivery values, estimated across a range of engine temperatures between said low temperature and said high temperature by interpolation based on said low temperature fuel mass value, said middle temperature fuel mass value, and said high temperature fuel mass value;
- and
- fuel mass injection timing to effect split injection effective to sustain said spark-assisted homogeneous-charge, compression-ignition operation.
Dependencies are inferred from the claim text.