Intake Manifold Air Pressure Control (P2-Control)
3. Intake manifold air pressure control (P2-control), engine 602.962A reference map (for P2-control) is stored in the EDS control unit. The intake manifold air pressure values received by the control unit relative to the injection volume and engine speed generate optimal engine (combustion) management, maximizing performance and minimizing NOx, HC and particulate emissions.
Function
By reducing the intake manifold air pressure (P2) during partial load operation, a reduction in particle emission is achieved.
The EDS control unit contains a closed loop circuit which compares "P2 actual" to "P2 specified" (see block diagram). Any pressure difference is equalized by actuation of the wastegate or the intake manifold air pressure control valve. These valves are operated by two vacuum actuators which receive electronically controlled vacuum via the vacuum transducers.
Boost control is dependent on:
^ Coolant temperature,
^ Intake air temperature,
^ Intake air pressure at the valves (P2 pressure),
^ Engine speed,
^ Fuel rack position.
Block Diagram, Intake Manifold Air Pressure Control (P2-control):
