ABSTRACT
Garrett developed the first monoblock arm and valve in 2013 for durability, controllability and noise perspective. The first application was mono-scroll coupled
with a pneumatic actuator. The global trend is to switch from pneumatic to electric actuator and the customer requirement to use monoblock with twin scroll turbocharger for durability perspective forced engineers to revisit the complete monoblock design.
Based on this new requirement, new CFD and new Adams studies have been run to completely upgrade the design. The systemic approach and the better understanding of valve interaction with engine control helped us to push again the limit of the monoblock concept. Monoblock arm & valve is now applicable with electric actuator and twin scroll application. It helps to reduce kinematic load, it improves valve progressivity, it provides a better sealing and improves engine catalyst light off.
NOMENCLATURE
MNB Monoblock
A&V Arm and Valve
A leak area
pi internal pressure
pa external pressure
ρi internal density
γ adiabatic gas exponent
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