Valvetronic servomotor
The third generation Valvetronic servomotor also contains the sensor for identifying the position of the eccentric shaft. Another special feature is that the Valvetronic servomotor is surrounded by engine oil. An oil spray nozzle ensures that the screw drive for the eccentric shaft is lubricated.
A brush-less direct current motor with integrated position sensor is used as the Valvetronic servomotor. This direct current motor is maintenance-free thanks to the contact-free power transformation and is very powerful (improved efficiency). Thanks to the use of integrated electronic modules, the Valvetronic servomotor can be controlled very precisely.
Example N55
| Item | Explanation |
|---|---|
| 1 | Socket |
| 2 | Worm shaft |
| 3 | Needle bearing |
| 4 | Bearing cap |
| 5 | Magnet sensor wheel |
| 6 | Rotor with 4 magnets |
| 7 | Sensor |
| 8 | Stator |
| 9 | Housing |
| 10 | Bearing |
The activation of the Valvetronic servomotor is limited to a maximum of 40 amperes. For a period greater than 200 milliseconds, a maximum of 20 amperes is available. The Valvetronic servomotor is activated via pulse-width-modulation. The duty cycle is between 5 and 98 %.
The following graphic shows the Valvetronic components in engine N55.
Example N55
| Item | Explanation |
|---|---|
| 1 | Oil spray nozzle |
| 2 | Eccentric shaft |
| 3 | Torsion spring |
| 4 | Gate |
| 5 | Intake camshaft |
| 6 | Intermediate lever |
| 7 | Roller cam followers |
| 8 | Hydraulic valve clearance compensation |
| 9 | Valve spring 10 Intake valve |
| 11 | Valvetronic servomotor |
| 12 | Exhaust valve |
| 13 | Valve spring |
| 14 | Hydraulic valve clearance compensation |
| 15 | Roller cam followers |
| 16 | Exhaust camshaft |
| 17 | Sealing cup |
| 18 | 12-pin plug connection |
The Valvetronic servomotor is supplied by the Digital Engine Electronics (DME) with 5 Volts. 5 Hall effect sensors provide the Digital Engine Electronics (DME) with signals. Of the 5 hall effect sensors, 3 are used for approximate identification and 2 for detailed classification. This means that the angle of rotation of the Valvetronic servomotor can be determined at < 7.5°. Thanks to the ratio of the worm shaft, this permits a very precise and rapid stroke adjustment of the valve lift.