Filter clogging and power loss issues while running a diesel engine with waste cooking oil

Abstract

As with other vegetable oils, the high viscosity of waste cooking oil (WCO) poses some challenges to engine operation. One of them is filter clogging. In this research, it was found that heating to above 55°C was effective in preventing clogging. However, the head loss across the filter was about 6 times higher than that of diesel. Generally, the lower calorific values of vegetable oils are held responsible for the reduction in maximum power of the engine. While running with WCO, the maximum power of the engine was reduced by 10.9 per cent from that with diesel. Raising the fuel tank level and dividing the flow through two filters to compensate for the higher head loss across the filter reduced the maximum power loss to 5.0 and 8.8 per cent respectively. Therefore, higher head loss in the filter is also responsible for the loss of maximum power. In terms of combustion, WCO had a shorter ignition delay compared with diesel, resulting in a less intense premixed combustion phase. The CO and NO emissions were on the average 8.4 and 16.2 per cent higher than those for diesel.