In addition to maintaining optimal valvetrain clearances, Eaton Deactivating Hydraulic Lash Adjusters (DHLA) in type II (end pivot overhead camshaft) and type V (pushrod overhead valve) valvetrain architectures can perform cylinder deactivation (CDA) to achieve optimal engine performance and improve fuel economy.
Replacing a standard lift control with a variable valve lifter, increases efficiency and fuel economy.
Dual mode operation delivers significant improvement in overall fuel efficiency by reducing air pumping losses.
Optimizes airflow efficiency with seamless switching from normal to low lift occurring in less than one camshaft revolution.
Maintains centerlines and utilizing existing envelope
In addition to using Eaton Switching Roller Finger Follower (SRFF) technology, cylinder deactivation (CDA) can also be performed through the use of Eaton Deactivating Hydraulic Lash Adjusters.
Here are the basic principles of Deactivating Hydraulic Lash Adjuster technology:
The Deactivating HLA is pushed up by the lost motion spring to the hard stop. After that the Deactivating HLA covers possible mechanical lashes in the system
The Oil Control Valve (OCV) is in ‘off’ mode. Oil to the pin is <0.7bar. The cam pushes on the Roller Rocker Arm (RRA) that covers the mech lash on the pin and then transfers the motion to the valve.
The OCV is in ‘on’ mode. Oil pressure to the pin is >1.5bar and the pin moves back. The cam pushes on the RRA that transfers the motion to the HLA because the lost motion spring is weaker than the valve spring.
In end pivot overhead camshaft architectures, the deactivating HLA is located in the cylinder head. By locating the deactivating element at the pivot of the type II valvetrain, high stiffness can be achieved enabling high engine rpm operation.
In pushrod overhead valve architectures, the deactivating HLA is located in the engine block. By placing the deactivating element in the block a compact low package height solution is obtained.
