Characteristic-map-regulated oil-pressure control
The oil pressure also controls the supplied oil volume in line with requirements.
However, the DME controls the characteristic-map-regulated oil-pressure control. To this end, the following input variables are used:
- Engine speed
- Engine temperature
- Load
The following overview shows a diagram of the regulating circuit:
| Index | Explanation |
|---|---|
| 1 | Engine (e.g. N53) |
| 2 | Signals from the sensors on the engine |
| 3 | Oil pressure sensor |
| 4 | Signal from oil pressure sensor |
| 5 | DME control module |
| 6 | Activation of the oil pressure regulating valve (3/2-way valve) |
| 7 | Oil filter |
| 8 | Venting of the oil pressure regulating valve |
| 9 | Oil pressure control valve |
| 10 | Control line for oil pressure regulating valve |
| 11 | Oil sump |
| 12 | Oil pump |
The DME activates the oil pressure regulating valve with a pulse-width modulated signal. The oil pressure regulating valve then sets the corresponding oil pressure that is applied to the control piston of the oil pump.
The characteristic-map-regulated oil pump enables even more precise control of the oil pump. This means that the measure makes an additional contribution to reducing fuel consumption and lowering the level of CO2 .
The required oil pressure is lowered via the engine speed range. Compared to volume-flow control, the oil pump has to generate less pump output.
The diagram shows load-dependent oil pressure at an engine oil temperature of 100 °C
| Index | Explanation |
|---|---|
| 1 | Curve 20 % |
| 2 | Curve 25 % |
| 3 | Curve 50 % |
| 4 | Curve 75 % |
| 5 | Curve 100 % (full load) |
| 6 | Curve for volume-flow control, e.g. N52 |