Split cycle waste heat method for combustion initiation in gasoline compression ignition engine
Systems and methods for having discrete valve opening and closing timings for different pairs of the combustion cylinders, and transitioning an engine from a Low temperature Combustion (LTC) mode to a Gasoline Compression Ignition (GCI) mode are provided. The method may comprise performing a cold start on an engine, comprising at least two sets of cylinders, in a Spark Ignition (SI) mode. The method may comprise, using a discrete camshaft operation for different pairs of the combustion cylinders to run the at least two sets of cylinders in the LTC mode, and when a load operation point of the engine increases, transitioning a first set of cylinders, of the at least two sets of cylinders, to run in a SI mode, and, after the first set of cylinders is transitioned to run in the SI mode, transitioning the second set of cylinders to run in the GCI mode, and, after the second set of cylinders is transitioned to run in the GCI mode, transitioning the first set of cylinders to run in the GCI mode.
1. A method for transitioning an engine from a Low temperature Combustion (LTC) mode to a Gasoline Compression Ignition (GCI) mode, comprising:
performing a cold start on an engine, wherein:
the engine comprises at least two sets of cylinders, wherein each set of cylinders comprises a two-cylinder pair of cylinders, and
each pair of cylinders is capable of differing camshaft operating points, consisting of identical cam lob shapes with discrete control mechanisms consisting of a CVVD mechanism on each discrete pair of cylinders, and a discrete CVVT system on each discrete pair of cylinders,
performing the cold start comprises running all of the at least two sets of cylinders in a Spark Ignition (SI) mode; and
using a discrete camshaft operation for a different pair of combustion cylinders to run all of the at least two sets of cylinders in a LTC mode:
when a load operation point of the engine increases:
transitioning a first set of cylinders, of the at least two sets of cylinders, to run in a SI mode; and
after the first set of cylinders is transitioned to run in the SI mode, transitioning a second set of cylinders, of the at least two sets of cylinders, to run in the GCI mode; and
after the second set of cylinders are transitioned to run in the GCI mode:
transitioning the first set of cylinders to run in a GCI mode.
2. The method of claim 1 , wherein running in the LTC mode comprises:
running with a negative valve overlap using a discrete camshaft operation for a different pair of combustion cylinders,
wherein, the exhaust valve closing timing is earlier than the intake valve opening timing.
3. The method of claim 1 , wherein transitioning the first set of cylinders to run in the GCI mode is performed when the load operation point increases to approximately 4 bar brake mean effective pressure (BMEP).
4. The method of claim 1 , further comprising, when the at least two sets of cylinders are transitioned to run in the LTC mode:
transitioning the first set of cylinders or the second set of cylinders to run in the SI mode for one or more cycles in order to build exhaust energy for turbocharger to have higher boost for transitioning the at least two sets of cylinders to run in the GCI mode.
5. The method of claim 1 , further comprising, when the at least two sets of cylinders are transitioned to run in the LTC mode:
transitioning all of the at least two sets of cylinders to run in the SI mode for one or more cycles in order to build exhaust energy for turbocharger to have higher boost for transitioning the at least two sets of cylinders to run in the GCI mode.
6. The method of claim 1 , wherein the first set of cylinders and the second set of cylinders are configured to be controlled independently from each other.
7. A system for transitioning an engine from a Low temperature Combustion (LTC) mode to a Gasoline Compression Ignition (GCI) mode, comprising:
an engine comprising at least two sets of cylinders, wherein each set of cylinders comprises a two-cylinder pair of cylinders
wherein the engine is configured to perform a cold start on an engine, comprising running all of the at least two sets of cylinders in a Spark Ignition (SI) mode; and
a discrete camshaft for a different pair of combustion cylinders configured to run all of the at least two sets of cylinders in a LTC mode:
when a load operation point of the engine increases:
transition a first set of cylinders, of the at least two sets of cylinders, to run in a SI mode; and
after the first set of cylinders is transitioned to run in the SI mode, transition a second set of cylinders, of the at least two sets of cylinders, to run in the GCI mode; and
after the second set of cylinders is transitioned to run in the GCI mode:
transition the first set of cylinders to run in a GCI mode.
8. The system of claim 7 , wherein running in the LTC mode comprises:
running with no airflow control; and
running with a negative valve overlap using a discrete camshaft operation for a different pair of combustion cylinders,
wherein, the exhaust valve closing timing is earlier than the intake valve opening timing.
9. The system of claim 7 , wherein the discrete camshaft operation for a different pair of combustion cylinders is configured to transition the first set of cylinders to run in the GCI mode when the load operation point increases to approximately 4 bar brake mean effective pressure (BMEP).
10. The system of claim 7 , wherein the discrete camshaft operation for a different pair of combustion cylinders is configured to, when the at least two sets of cylinders are transitioned to run in the LTC mode:
transition the first set of cylinders or the second set of cylinders to run in the SI mode for one or more cycles in order to build exhaust energy for turbocharger to have higher boost for transitioning the at least two sets of cylinders to run in the GCI mode.
11. The system of claim 7 , wherein the discrete camshaft operation for a different pair of combustion cylinders is configured to, when the at least two sets of cylinders are transitioned to run in the LTC mode:
transition all of the at least two sets of cylinders to run in the SI mode for one or more cycles in order to build exhaust energy for turbocharger to have higher boost for transitioning the at least two sets of cylinders to run in the GCI mode.
12. The system of claim 7 , wherein the first set of cylinders and the second set of cylinders are configured to be controlled independently from each other.