At Translume, the phrase ‘Soot Monitoring’ means more than just tracking the number or concentration of soot particles. This measurement alone gives, at best, an incomplete picture. Our system is designed to capture this information, while at the same time indicating when the onset of soot agglomeration occurs. At this critical point, when soot density is such that particles join together, the potential for significant damage accelerates greatly. By monitoring both density and agglomeration over time, the information provided by the Translume system allows for intervention at the optimal time – before significant damage can occur.

Soot Generation

Soot, comprised 98% of carbon by weight, is formed during the combustion process. Soot formation is more pronounced in diesel engines than gasoline engines. Historically most of the soot content was released to the atmosphere while a small fraction entered the crankcase and the lubricant with combustion gas blow-by, or through deposition on cylinder walls that was subsequently scraped off by the rings and deposited into the oil.

U.S. Environmental Protection Agency is steadily adopting more rigorous nitro-oxidation and hydrocarbon emission policies for diesel engines. These new environmental policies spell good news for the environment, but bad news for lubricants as engine manufacturers are increasingly using exhaust gas recirculation (EGR) to reduce atmospheric soot emissions. EGR sends some of the engine emissions, including soot, back to the combustion chamber creating a multi-pass opportunity for the soot to ingress to the lubricating oil

References:
- Drew D. Troyer 'Get Ready for More Soot', Practicing Oil Analysis Magazine (1999, July-August)
- M. Manni, S. Florio, C. Gommellini, 'Impact of fuel and oil quality on deposits, wear and emissions from a light duty diesel engine with high EGR', SAE technical paper series, 2000-01-1913, (2000)
- David Doyle, CTC Analytical Services, 'EGR Systems and Lubricating Oil in Diesel Engines', Practicing Oil Analysis Magazine (July 2002).

Soot Load

Soot particles, as found in fresh lubricating oil, typically have diameters in the 60- to 200-nanometer range. For most combustion engines, the soot content or soot load increases more or less linearly with the number of hours of operation since the last oil change

References:
- Gerardo Trujillo, Noria Latin America, 'Resetting Oil Analysis Parameters for Changing Diesel Engines'. Practicing Oil Analysis Magazine. January 2004.
- J. A. Mc. Geehan, W. Alexander, J. N. Ziemer, S. H. Roby, and J. P. Graham 'The pivotal role of crankcase oil in preventing soot wear and extending filter life in low emission diesel engines'. SAE technical paper series, 1999-01-1525, (1999).

Soot Agglomeration

Although the majority of soot produced during combustion exits through the exhaust, some passes through the rings of the combustion chamber and enters the engine oil. As long as these soot particles remain suspended in the oil and are not allowed to agglomerate they pose little risk to engine parts.

It is up to the motor oil’s dispersants to keep soot particles dispersed. However, in high soot conditions, dispersants can become quickly depleted. Once this happens the soot particles rapidly agglomerate to form particles with diameters well over a micron.

References:
- Drew Troyer & Jim Fitch, 'Oil Analysis Basics', published by Noria Corporation.

Effect of Soot Agglomeration

Large agglomerated soot particles cause abrasive action on the engine bearings. This is most insidious in regions of high-load where oil films are on the order of microns or less.

Agglomerated soot can also form sludges that eventually impede oil flow, and can be deposited on oil filters, blocking oil flow and allowing dirty oil into the engine. In addition, high soot levels increase viscosity, further impeding oil flow and increasing engine wear. Anti-wear additive performance is also affected in high soot conditions as an increase in wear and premature engine failure.

Another effect of high soot conditions is the deposition of carbon particles in the piston ring grooves, causing degradation of the oil seal between the ring and cylinder liner and abrading the ring and liner. As the gap between the ring and liner increases, combustion byproducts such as gases and unburned fuels leak past the piston rings and enter the crankcase, a problem known as blowby. This reduces engine efficiency and contaminates the motor oil. Ring sticking and poor heat transfer from the piston to the cylinder wall can also result.

Translume Soot State Monitoring System

The Translume real-time, on-line soot state oil monitoring system is based on direct optical measurements. This is in contrast to other systems that measure surrogates, such as dielectric constant, which may be influenced by many parameters besides soot (e.g. moisture).

Real-time data from Translume's SootSmart Soot State Monitoring System gives time-sequence information that is significantly more valuable than single data points. The value of this data exceeds simple averaging of single-value data, and offers information not obtainable with traditional laboratory equipment.

Shown below are typical results from a road test. The point where detected soot increases rapidly, indicating the onset of soot particle agglomeration, is clearly evident. This pattern is repeated for all oil change cycles.

Translume's SootSmart system, shown below mounted on a oil filter cap, is offered both as an integrated component of an engine oil filter and in bolt-on configurations. It runs on engine oil pressure and the standard vehicle voltage.

Next Generation Fluid Monitoring System

Translume is developing other classes of systems to monitor various others fluids, including the montioring of particulates in hydraulic fluid and cooling fluid.

So Give Us a Call

For more information on how Translume's fluid sensors and integrated systems can change how you manage your processes, equipment and vehicles, please contact Eric Jacobson at 800-378-3505 or email us.