Improvements in Lubricating Oil Quality by an on Line Oil Recycler for a Refuse Truck Using in Service Testing

A method of cleaning lubricating oil on line was investigated using a fine bypass particulate filter followed by an infra red heater. Two bypass filter sizes of 6 and 1 micron were investigated, both filter sizes were effective but the one micron filter had the greatest benefit. This was tested on two nominally identical EURO 1 emissions compliance refuse trucks, fitted with Perkins Phazer 210Ti 6 liter turbocharged intercooled engines and coded as RT320 and RT321. These vehicles had lubricating oil deterioration and emissions characteristics that were significantly different, in spite of their similar age and total mileage. RT321 showed an apparent heavier black smoke than RT320. Comparison was made with the oil quality and fuel and lubricating oil consumption on the same vehicles and engines with and without the on-line bypass oil recycler. Engine oils were sampled and analyzed about every 400 miles. Both vehicles started the test with an oil drain and fresh lubricating oil. The two refuse trucks were tested in a different sequence, the RT320 without the recycler fitted and then fitted later and the RT321 with the recycler fitted and then removed later in the test and both without any oil change. The RT320 was also the one with the finer bypass filter. The test mileage was nearly 8,000 miles both trucks. The amount of fresh oil top up was monitored and the results corrected for this dilution effect. The results showed that the on-line bypass oil recycler cleaning system reduced the rate of fall of the TBN by 23% and 49% for two trucks respectively. A 73% reduction in the rate of increase of the TAN incurred for one of the trucks. The soot in oil was reduced by \mA70% on average for both trucks. The reduction in the rate of carbon accumulation in oil was 55% for the refuse truck with heavy smoke emissions. There was a 56% reduction in iron. The rate of oxidation, nitration and sulfation of oils was significantly reduced. There was an improvement of the fuel economy of about 3%. The lubricating oil consumption was reduced by 40% for 1 micron recycler filter and 30% for 6 micron filter.