Effective Control Of Friction Part Wear In Diesel Engines

Filtek India (P) Ltd was incorporated in June 2004 with a view to develop the centrifugal oil cleaners for the marine engine industry. The founder Mr. B.K. Patwardhan was involved with the electronic engine monitoring system on diesel engine application since 1988 for which he has a patent in his name.

Diesel Engine design has come a long way since the past two decades. Environment regulations are more strict regarding emissions, engine operators today, are demanding much longer oil drain intervals and extended intervals between overhauls, typically in excess of one million kilometers for heavy duty engines installed in road haulage vehicles. Similar extended engine lives are also being expected in the medium and low speed engine fields especially in marine applications.

It is recognized that’s lubricating oil contamination is a primary reason for engine wear, reduced fuel efficiency and engine performance. Thus lubrication is in the life blood of the engine.

An effective filtration system is being increasingly recognized as highly beneficial. A great deal of the damage to engine working parts is caused by particles ranging from 0.25 microns to 3 microns. The full flow filters used on the engine are rated typically from 40 microns and above. These filters only stop the larger particles from entering the system but particles smaller than their pore size, typically 5 micron and below are not addressed and stopped from entering the oil path. Even high speed diesel engines with bypass filters rated at 5 microns still allow smaller particles in the oil system. The particles that cause maximum damage to the engine friction parts is the small particles ranging from 0.5 micron to 2 microns. These are the particles that find their way between a crankshaft and main bearings, con rod bearings and camshaft, piston rings and liners, where the only clearance between the mating surfaces is 0.5 microns or 1 microns. When these particles get lodged in these clearances they cause scuffing on the softer bearing materials and increase the clearances.

No cleanable strainer or cartridge type filter is known to stop these tiny particles in the oil. These particles can be removed from the system only by centrifuging the oil. Glacier Centrifuges UK are the pioneers of this technology and offered a unique product which could be mounted on the engine or near the engine and could develop centrifugal force in excess of 2000 G at 6000 RPM purely by the oil pressure of the engine being fed to the centrifuge. This technology eliminated the need for pump and motor to develop the oil pressure. Analysis showed that 90% of the captured sludge was in the range of 0.25 micron to 2 microns. Oil additive parameters were maintained much longer and many big engine makers all over the world use centrifugal oil filters as a standard fitment.

Oil change intervals have been extended upto 50%. Analysis of the sludge collected by the centrifuge has shown it to be effective at removing abrasive particles down to less than one micron.

Small particles can find their way into engine oil from many different sources. Fine airborne dust ingested with combustion air is deposited on cylinder walls, from where it is scraped into the oil by the piston rings. Oil can also be contaminated by dirty fuel and careless maintenance practice. These small particles present in engine oil, continuously erode engine components, eventually causing them to wear out. Small particles can also catalyze oxidation of the oil, thickening it and shortening its life. A centrifuge effectively removes these particles.

Carbon soot formed in combustion chamber accounts for nearly 55% of the sludge and is a major headache for engine maintenance personnel. Carbon soot agglomerates to become a hard abrasive pack and causes wear and tear of friction parts. It also degrades the oil additive package and this results in costly oil changes. other abrasive particles. By removing a large portion of soot present in the oil, the centrifuge maintains the quality of the oil and extends its useful life.

Research and development has shown that centrifuge can reduce wear rates significantly. Engines operating under normal conditions have had piston ring wear halved by the use of a Filtek centrifuge. Trials done by Yanmar have proved that the bearing life is estimated to be even 3 times by use of a centrifuge.

The centrifuge is designed to keep engine lube oil free from abrasive particles. It achieves this by continuously cleaning the oil in the sump. A proportion of the lube oil from the oil pump is fed into the side inlet of the centrifuge. On entering the rotor assembly through the internal drilling of thr spindle, it exits through twin tangentially opposed nozzles at the base. The action of oil exiting from the bottom gives the rotor assembly a reverse direction spin, directly proportional to the inlet pressure resulting in tremendous centrifugal force exerted on the particle in the oil. All contaminants, insolubles suspended in the oil is forced to stick on the inside rotor wall while the clean oil is returned to the sump through the crankcase under gravity. The centrifuge selection is done so that the oil sump volume passes through the centrifuge at least 4 times in one hour, so as to remove the contaminant generation rate effectively from the engine. The Centrifuge has an in built provision to protect the engine from oil starvation. Environmental concerns have created the need for an efficient cleanable system for lube oil purification. Currently disposal of used oil filter elements is a toxic waste and must be incinerated. The Centrifuge eliminates the need and has no disposable filters/elements and is a fully cleanable system. Paper insert helps remove the dirt quickly and effectively.

An important point is that the efficiency of the centrifuge remains high throughout its working life. The dirt collected forms a dense cake on the rotor wall and therefore the flow of oil through the rotor is not impeded. As the dirt is stored in a condensed form, the amount collected by the centrifuge is significant.

Filtek Centrifugal Oil Cleaners are available for engine sizes upto 1500kw, although this can be increased by fitting two or more centrifuges per engine. Approx. 10% of the lube oil pump output is required to drive the centrifuge and this lies well within the excess capacity of most engine oil pumps. Should the output of the oil be marginal, a separate pump can be fitted to drive the centrifuge. The installation kit and data sheet provided by Filtek is self explanatory and the ship staff can easily install the centrifuge in the bypass lube oil circuit within an hour. Filtek Centrifuge can be cleaned while the engine is running by switching off the oil supply using a ball valve. The Centrifuge can be installed on all types of diesel engines ranging from 400 liters oil sump capacity to 3000 liters oil sump capacity and does not depend on the type of vessel, engine HP, KVA rating, type of engine or model of engine.