Variable intake valve closing using through axle rocker arm

A method of designing a through axle switching rocker arm comprising an outer arm, an inner arm and a roller axle, the inner arm pivotally coupled to the outer arm about a pivot axle and having an inner bushing that supports an inner roller, the inner bushing defining an inner diameter, the roller axle extending through the outer arm and supporting a pair of outer rollers, the roller axle extending through the inner bushing and defining an outer diameter, wherein the inner diameter of the inner bushing engages the outer diameter of the roller axle thereby inhibiting further pivoting of the inner arm relative to the outer arm defining a rocker arm travel constraint, the method comprising:

• designing first and second cam profiles based on the through axle switching rocker arm such that a difference in lift between the first and second cam profiles is held within the rocker arm travel constraint whereby the first cam profile defines an early intake valve closing profile, and the second cam profile defines a late intake closing profile;
• and
• operating the through axle switching rocker arm for selective and alternative operation in (i) a first arrangement with a first cam having the first cam profile that implements an early intake valve closing (EIVC) valve actuation strategy and in (ii) a second arrangement with a second cam having the second cam profile that implements a late intake valve closing (LIVC) valve actuation strategy.

A method of designing a through axle switching rocker arm comprising an outer arm, an inner arm and a roller axle, the inner arm pivotally coupled to the outer arm about a pivot axle and having an inner bushing that supports an inner roller, the inner bushing defining an inner diameter, the roller axle extending through the outer arm and supporting a pair of outer rollers, the roller axle extending through the inner bushing and defining an outer diameter, wherein the inner diameter of the inner bushing engages the outer diameter of the roller axle thereby inhibiting further pivoting of the inner arm relative to the outer arm defining a rocker arm travel constraint, the method comprising:

• designing first and second cam profiles based on the through axle switching rocker arm such that a difference in lift between the first and second cam profiles is held within the rocker arm travel constraint, wherein the first cam profile corresponds to a lift profile typifying a parabolic shape and the second cam profile corresponds to a lift profile typifying a parabolic shape and having an opening lead portion that increase a duration of a valve lift;
• and
• operating the through axle switching rocker arm for selective and alternative operation in (i) a first arrangement with a first cam having the first cam profile that implements an early intake valve closing (EIVC) valve actuation strategy and in (ii) a second arrangement with the second cam having a second cam profile that implements a late intake valve closing (LIVC) valve actuation strategy.