Intake port shutoff, function - GF14.20-P-3009P

ENGINE 642 in MODEL 164.1 /8, 203.0 /2, 209.3 /4, 211.0 /2 /6, 219.3, 221.0 /1, 251.0 /1 

ENGINE 642 in MODEL 463 

In the charge air manifold, 2 inlet ports are available for each cylinder. Each inlet port can be closed by a flap. The flaps are connected to each other with linkage. They are held in the open position by spring force. The position of the flaps at the inlet ports is determined by a performance map stored in the CDI control unit (N3/9). To do this, the CDI control unit reads information from the following components:

• Hot film mass air flow sensor left (B2/6) and right (B2/7)
• Charge pressure sensor (B5/1/)
• Charge air temperature sensor (B17/8)
• Pressure sensor downstream of air filter (B28/5) (except model 463)
• Pressure sensor downstream of air filter, right cylinder bank (B28/5) (Model 463)
• Accelerator pedal sensor (B37)
• Crankshaft Hall sensor (B70)

After evaluating the input signal, the CDI control unit actuates the motor for the inlet port shutoff switchover valve (M55) by means of a Pulse Width Modulation (PWM) signal. In the lower engine speed and load range, half of the inlet ports are closed by the flaps. In the open inlet ports, the flow speed is thus increased. This leads to a higher swirl. The resulting stronger swirl brings about a more effective premixing of the fuel with air, and therefore more efficient combustion and reduction of the amount of particulate matter (PM) in the exhaust gas. As the engine speed and engine load increase, the closed inlet ducts are continuously opened so that the best possible relationship between eddy and air mass is available for every operating phase of the engine. In this way, the exhaust characteristics and the engine performance are optimized.

If there is a fault or discontinuity in the supply voltage, the flaps are opened by spring force.