Method and device for the real-time measurement of the consumption of oil from an engine oil separation system, using radioactive tracers

1. A method for determining oil consumption coming from an oil separation system located in a circuit for recycling blowby gases of an internal combustion engine, comprising:

labeling the lubricating oil for said internal combustion engine by introducing at least one radioactive tracer into said lubricating oil;

passing the blowby gases, leaving the engine block and laden with lubricating oil, through the oil separation system, wherein at least some of the oil contained within said blowby gases is separated, collected and returned to an oil sump;

subsequently bringing the blowby gases coming from the oil separation system to an oil trapping device located downstream of said oil separation system, whereby the oil not separated from the blowby gases coming from the oil separation system is retained in the oil trapping device;

measuring the radioactivity of the oil retained in the oil trapping device by using a detector, which is placed near the oil trapping device and is sensitive to the ionizing radiation emitted by the radioactive tracer(s); and

transmitting the results of these measurements to a computer capable of calculating the consumption of lubricating oil not separated in said separation system from these results.

2. The method as claimed in claim 1 , wherein the oil separation system comprises several separators connected in series or in parallel.

3. The method as claimed in claim 1 , further comprising releasing the blowby gases coming from the trapping device into the atmosphere or to an intake (D) of the internal combustion engine.

4. The method as claimed claim 1 , wherein the oil trapping device is a second separation system comprising one or more static separation elements and/or one or more cyclones and/or one or more filtering elements.

5. The method as claimed in claim 1 , wherein the oil trapping device is designed so that the pressure difference (ΔP) between the inlet of the oil separation system and the outlet of the oil separation system is substantially the same as the value of this pressure difference in the absence of the trapping device.

6. The method as claimed in claim 1 , wherein the radioactive tracer is an organic or mineral compound of a radioactive element.

7. The method as claimed in claim 1 , wherein the radioactive element has a period, or half-life, of less than 3 years.

8. The method as claimed in claim 7 , wherein the radioactive element is selected from the group consisting of 22 Na, 65 Zn, 45 Ca, 35 S, 32 P, 47 Ca, 99 Mo, 82 Br, 64 Cu, 99m TC, 28 Mg, 68 Ge, 69 Ge, 77 Ge, 85 Sr and 56 Co.

9. The method as claimed in claim 8 , wherein the radio tracer is selected from the group consisting of tetra-alkylgermanes containing 69 Ge.

10. The method as claimed in claim 8 , wherein the radio tracer is 99m Tc.

11. The method as claimed in claim 8 , wherein the radio tracer is selected from the group consisting of tetrahexylgermane, tetraheptylgermane and tetraoctylgermane, and mixtures thereof.

12. The method as claimed in claim 8 , wherein the radio tracer is 99m Tc in the form of an aqueous solution of sodium pertechnetate NaTcO 4 or in the form of nanoscale particles isolated from the atmosphere by carbon.

13. The method as claimed in claim 1 wherein the detector is an ionizing radiation detection probe.

14. The method as claimed in claim 1 , wherein the radioactive element has a period, or half-life, of less than 1 year.

15. The method as claimed in claim 1 , wherein the radioactive element has a period, or half-life, of less than 30 days.

16. A device for determining the consumption of oil coming from an oil separation system located in a circuit for recycling blowby gases of an internal combustion engine, comprising:

an internal combustion engine lubricated by an oil labeled by introducing at least one radioactive tracer into said oil;

an oil separation system that receives the blowby gases laden with lubricating oil leaving the engine block, where at least some of the oil contained in said blowby gases is separated, collected and returned to the oil sump;

downstream of the oil separation system, an oil trapping device;

a detector sensitive to the ionizing radiation emitted by the radioactive tracer(s), located in the immediate vicinity of the trapping device, so as to measure the radioactivity of the oil not Separated in the oil separation system but retained in the oil trapping device; and

connected to said detector, a computer programmed for calculating the consumption of lubricating oil not separated in said separation system from the results of the radioactivity measurements.

17. The device as claimed in claim 16 , characterized in that the oil trapping device is designed in such a way that the pressure difference (ΔP) between the inlet and the outlet of the oil separation system is approximately the same as the value of this pressure difference in the absence of said oil trapping device.