Patent ID: 9127637
Filing Date: 2015-09-08
Classification: F02B,F02D,F02P,Y02T

Abstract:
1. A combustion mode transition control method for controlling a transition between a homogeneous-charge compression-ignition (HCCI) combustion mode and a spark-ignition (SI) combustion mode in a direct-injection internal combustion engine including an intake camshaft with a low-lift intake cam and a high-lift intake cam, a variable lift control for selectively operating an intake valve in one of a low-lift intake valve profile with the low-lift intake cam and a high-lift intake valve profile with the high-lift intake cam, a variable cam phase control operative on the intake camshaft for simultaneously controlling phase settings of the low-lift intake cam and the high-lift intake cam, an exhaust camshaft with a low-lift exhaust cam and a high-lift exhaust cam, a variable lift control for selectively operating an exhaust valve in one of a low-lift exhaust valve profile with the low-lift exhaust cam and a high-lift exhaust valve profile with the high-lift exhaust cam, a variable cam phase control operative on the exhaust camshaft for simultaneously controlling phase settings of the low-lift exhaust cam and the high-lift exhaust cam, an ignition spark control, a fuel injection control, said transition control comprising: slowly transitioning the intake and exhaust camshafts from initial phase settings corresponding to a first combustion mode comprising one of said HCCI and SI combustion modes to target phase settings corresponding to a second combustion mode comprising the other of said HCCI and SI combustion modes; and coordinating an ignition spark timing and an injected fuel mass with said transitioning of the intake and exhaust camshaft phase settings to substantially maintain engine load continuity during the transitioning of the intake and exhaust camshaft phase settings, the coordinating of the ignition spark timing comprising over-advancing ignition spark timing and then retarding ignition spark timing to a final desired combustion mode setting in the second combustion mode comprising the other of said HCCI and SI combustion modes; wherein the first combustion mode comprises the HCCI combustion mode, the initial phase settings of the intake and exhaust camshafts comprise a negative overlap of the low-lift valve profiles, and the target phase settings of the intake and exhaust camshafts comprise a positive overlap of the high-lift valve profiles; the transition between the initial phase settings and the target phase settings of the intake and exhaust camshafts further comprising quickly transitioning to an intermediate positive overlap of the high-lift valve profiles less than the positive overlap of the high-lift valve profiles in the target phase settings, and then slowly transitioning from the intermediate positive overlap of the high-lift valve profiles to the target phase settings of the intake and exhaust camshafts.