Intake Manifold Air Pressure Control
Intake manifold air pressure control may also be referred to as P-2 control. The intake manifold air pressure control valve is mounted on the intake manifold air pressure control valve body and controlled by the intake manifold air pressure control valve vacuum transducer. The intake manifold air pressure control valve induces a pressure differential between the exhaust and intake manifolds by partially obstructing the intake during EGR operation. A minimum opening around the edge of intake manifold air pressure control valve is always present, even when intake manifold air pressure control valve is not actuated.
A reference map is stored in EDS control unit. Intake manifold air pressure values received by EDS control unit relative to injection volume and engine speed generate optimal engine management, maximizing performance and minimizing emissions. See Fig 1 .
Reducing intake manifold air pressure during partial load operation reduces particle emissions. EDS control unit contains a closed loop circuit which compares actual manifold air pressure to a preset specified manifold air pressure. Any pressure difference is equalized by actuation of wastegate or intake manifold air pressure control valve.