Controlled Variables

Among other things, the following variables influence boost pressure control in the N63 engine:

• Intake-air temperature
• Engine speed
• Throttle-valve position
• Ambient pressure
• Intake-manifold pressure
• Pressure before the throttle valve (reference variable)

The electropneumatic pressure transducers are activated by the engine control unit on the basis of these variables.

The result of this activation can be checked from the boost pressure achieved, which is measured before the throttle valve.

There follows a comparison of the boost pressure achieved with the setpoint data from the characteristic map, which can, if necessary, give rise to an activation correction.

The system therefore controls and monitors itself during operation.

Fig 1: Engine Boost Pressure Characteristic Map

Courtesy of BMW OF NORTH AMERICA, INC.