How to solve the trouble of BMW 523 air intake system

106 104, fully variable air intake system, servo motor 2: control, open circuit. This N52 engine is equipped with a fully variable intake system. The torque produced by the engine largely depends on the intake quality of fresh air in the intake stroke. The intake stroke of each cylinder, that is, the downward stroke of the piston when the valve is opened, causes the intake mass to oscillate. When the moving air mass of the intake cylinder meets the closed intake valve of the cylinder, the above oscillation will be superimposed with the oscillation generated by the pressure peak. When these two kinds of oscillations are superimposed, so-called resonance or * * * vibration will occur. Resonance can amplify or weaken the original oscillation. At the beginning of the intake stroke, whether there is a pressure peak or a pressure valley in front of the intake valve depends to a great extent on the stroke of superimposed oscillation in the intake area and the engine speed, that is, the airflow speed. The demand for higher torque in a larger engine speed range leads to more and more types of engine intake ports. Therefore, the geometry and control of air intake device have great influence on the quality of cylinder ventilation. The fixed length intake pipe can only produce the best cylinder intake effect at a specific engine speed. It is conditional to increase torque within a specific speed range. Because when the N52 reaches the maximum speed of 7000 r/min, the previously used two-stage DISA will produce a torque trough in the middle speed range. In order to generate high torque in the middle engine speed range, the N52 is equipped with a three-stage DISA, that is, a fully variable intake system. The total variable intake system of N52 consists of an intake pipe switching device with two DISA actuators and an overflow pipe located in the intake range.