Patent 8055435 was granted and assigned to Toyota on November, 2011 by the United States Patent and Trademark Office.
In a low load region where torque is lower than T1 but is not lower than T2, the present invention uses a lean single valve small operating angle mode to provide a lean burn in a single valve small operating angle state or uses an EGR single valve small operating angle mode to provide external EGR in a single valve small operating angle mode.