Engine warm-up of a homogeneous charge compression ignition engine
View Patent ↗Cold start and warm-up operations of an HCCI engine are improved through coordinated control of engine valves, fuel injection and spark timing.
1. A method of operating a four-stroke internal combustion engine including 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, a direct injection fuel system and a spark ignition system, comprising:
during engine cranking at cold start conditions within a predetermined engine temperature range and for a duration thereafter until a predetermined engine temperature, operating said engine in a spark-assist start mode including:
controlling said intake and exhaust valves to effect a partial-lift, negative valve overlap in a range of about 180 to about 200 crank angle degrees;
controlling said fuel system to deliver a first injection of fuel during said negative valve overlap and a second injection of fuel during said compression stroke of said piston; and,
controlling said spark ignition system to effect spark ignition.
2. The method of claim 1 , wherein said operating said engine in said spark-assist start mode warms said engine sufficiently such that subsequent engine operation is capable of homogeneous charge compression ignition operation without spark-assist.
3. The method of claim 1 , further comprising:
during engine cranking at cold start conditions within a second predetermined engine temperature range colder than said predetermined engine temperature range, operating said engine in a cold start mode including:
controlling said intake and exhaust valves to effect a partial-lift, negative valve overlap in a range of about 0 to about 60 crank angle degrees;
controlling said fuel system to deliver a first injection of fuel during said negative valve overlap and a second injection of fuel during said compression stroke of said piston; and,
controlling said spark ignition system to effect spark ignition; and,
subsequent to operating engine in said cold start mode, operating said engine in a first warm-up mode including:
controlling said intake and exhaust valves to effect a partial-lift, negative valve overlap in a range of about 180 to 200 crank angle degrees,
controlling said fuel system to deliver a first injection of fuel during said negative valve overlap and a second injection of fuel during said compression stroke of said piston; and,
controlling said spark ignition system to effect spark ignition.
4. The method of claim 3 , wherein said operating said engine in said first warm-up mode warms said engine sufficiently that subsequent engine operation is capable of homogeneous charge compression ignition operation without spark-assist.
5. The method of claim 3 , further comprising:
during engine cranking at cold start conditions within a third predetermined engine temperature range colder than said second predetermined engine temperature range, operating said engine in a crank and fire start mode including:
controlling said intake and exhaust valves to effect a full-lift, minimum valve overlap of no greater than about 40 crank angle degrees;
controlling said fuel system to deliver one of a split and single injection of fuel during said compression stroke of said piston; and,
controlling said spark ignition system to effect spark ignition;
subsequent to operating said engine in said crank and fire start mode, operating said engine in a catalyst heating mode including:
controlling said intake and exhaust valves to effect a full-lift, negative valve overlap in a range of about 0 to about 40 crank angle degrees;
controlling said fuel system to deliver a first injection of fuel during said intake stroke of said piston and a second injection of fuel during said compression stroke of said piston; and,
controlling said spark ignition system to effect retarded spark ignition; and,
subsequent to operating said engine in said catalyst heating mode, operating said engine in a second warm-up mode including:
controlling said intake and exhaust valves to effect a partial-lift, negative valve overlap in a range of about 180 to about 200 crank angle degrees,
controlling said fuel system to deliver a first injection of fuel during said negative valve overlap and a second injection of fuel during said compression stroke of said piston; and,
controlling said spark ignition system to effect spark ignition.
6. The method of claim 5 , wherein said operating said engine in said second warm-up mode warms said engine sufficiently that subsequent engine operation is capable of homogeneous charge compression ignition operation without spark-assist.
7. The method of claim 5 , wherein said controlling said spark ignition system to effect retarded spark ignition effects post top dead center ignition.
8. The method of claim 1 , further comprising:
during engine cranking at cold start conditions within a second predetermined engine temperature range colder than said predetermined engine temperature range, operating said engine in a crank and fire start mode including:
controlling said intake and exhaust valves to effect a full-lift, minimum valve overlap of no greater than about 40 crank angle degrees;
controlling said fuel system to deliver one of a split and single injection of fuel during said compression stroke of said piston; and,
controlling said spark ignition system to effect spark ignition;
subsequent to operating said engine in said crank and fire start mode, operating said engine in a catalyst heating mode including:
controlling said intake and exhaust valves to effect a full-lift, negative valve overlap in a range of about 0 to about 40 crank angle degrees;
controlling said fuel system to deliver a first injection of fuel during said intake stroke of said piston and a second injection of fuel during said compression stroke of said piston; and,
controlling said spark ignition system to effect retarded spark ignition; and,
subsequent to operating said engine in said catalyst heating mode, operating said engine in a warm-up mode including:
controlling said intake and exhaust valves to effect a partial-lift, negative valve overlap in a range of about 180 to about 200 crank angle degrees;
controlling said fuel system to deliver a first injection of fuel during said negative valve overlap and a second injection of fuel during said compression stroke of said piston; and,
controlling said spark ignition system to effect spark ignition.
9. The method of claim 8 , wherein said operating said engine in said warm-up mode warms said engine sufficiently that subsequent engine operation is capable of homogeneous charge compression ignition operation without spark-assist.
10. The method of claim 8 , wherein said controlling said spark ignition system to effect retarded spark ignition effects post top dead center ignition.
11. A method of operating a four-stroke internal combustion engine including 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, a direct injection fuel system and a spark ignition system, comprising:
during engine cranking at cold start conditions within a predetermined engine temperature range, operating said engine in a cold start mode including:
controlling said intake and exhaust valves to effect a partial-lift, negative valve overlap in a range of about 0 to about 60 crank angle degrees;
controlling said fuel system to deliver a first injection of fuel during said negative valve overlap and a second injection of fuel during said compression stroke of said piston; and,
controlling said spark ignition system to effect spark ignition; and,
subsequent to operating said engine in said cold start mode, operating said engine in a first warm-up mode including:
controlling said intake and exhaust valves to effect a partial-lift, negative valve overlap in a range of about 180 to about 200 crank angle degrees;
controlling said fuel system to deliver a first injection of fuel during said negative valve overlap and a second injection of fuel during said compression stroke of said piston; and,
controlling said spark ignition system to effect spark ignition.
12. The method of claim 11 , wherein said operating said engine in said first warm-up mode warms said engine sufficiently that subsequent engine operation is capable of homogeneous charge compression ignition operation without spark-assist.
13. The method of claim 11 , further comprising:
during engine cranking at cold start conditions within a second predetermined engine temperature range colder than said predetermined engine temperature range, operating said engine in a crank and fire start mode including:
controlling said intake and exhaust valves to effect a full-lift, minimum valve overlap of no greater than about 40 crank angle degrees;
controlling said fuel system to deliver one of a split and single injection of fuel during said compression stroke of said piston; and,
controlling said spark ignition system to effect spark ignition;
subsequent to operating said engine in said crank and fire start mode, operating said engine in a catalyst heating mode including:
controlling said intake and exhaust valves to effect a full-lift, negative valve overlap in a range of about 0 to about 40 crank angle degrees;
controlling said fuel system to deliver a first injection of fuel during said intake stroke of said piston and a second injection of fuel during said compression stroke of said piston; and,
controlling said spark ignition system to effect retarded spark ignition; and,
subsequent to operating said engine in said catalyst heating mode, operating said engine in a second warm-up mode including:
controlling said intake and exhaust valves to effect a partial-lift, negative valve overlap in a range of about 180 to about 200 crank angle degrees;
controlling said fuel system to deliver a first injection of fuel during said negative valve overlap and a second injection of fuel during said compression stroke of said piston; and,
controlling said spark ignition system to effect spark ignition.
14. The method of claim 13 , wherein said operating said engine in said second warm-up mode warms said engine sufficiently that subsequent engine operation is capable of homogeneous charge compression ignition operation without spark-assist.
15. The method of claim 13 , wherein said controlling said spark ignition system to effect retarded spark ignition effects post top dead center ignition.
16. A method of operating a four-stroke internal combustion engine including 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, a direct injection fuel system and a spark ignition system, comprising:
during engine cranking at cold start conditions operating said engine in a crank and fire start mode including:
controlling said intake and exhaust valves to effect a full-lift, minimum valve overlap of no greater than about 40 crank angle degrees;
controlling said fuel system to deliver one of a split and single injection of fuel during said compression stroke of said piston; and,
controlling said spark ignition system to effect spark ignition;
subsequent to operating said engine in said crank and fire start mode, operating said engine in a catalyst heating mode including:
controlling said intake and exhaust valves to effect a full-lift, negative valve overlap in a range of about 0 to about 40 crank angle degrees;
controlling said fuel system to deliver a first injection of fuel during said intake stroke of said piston and a second injection of fuel during said compression stroke of said piston; and,
controlling said spark ignition system to effect retarded spark ignition; and,
subsequent to operating said engine in said catalyst heating mode, operating said engine in a warm-up mode including:
controlling said intake and exhaust valves to effect a partial-lift, negative valve overlap in a range of about 180 to about 200 crank angle degrees;
controlling said fuel system to deliver a first injection of fuel during said negative valve overlap and a second injection of fuel during said compression stroke of said piston; and,
controlling said spark ignition system to effect spark ignition.
17. The method of claim 16 , wherein said operating said engine in said warm-up mode warms said engine sufficiently that subsequent engine operation is capable of homogeneous charge compression ignition operation without spark-assist.
18. The method of claim 16 , wherein said controlling said spark ignition system to effect retarded spark ignition effects post top dead center ignition.