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(3-09) Combustion Characteristics of Diesel Engines with Waste Vegetable Oil Methyl Ester((AF-3)Alternative Fuels 3-Biomass Fuels and Fuel Design)

2001; Japan Society Mechanical Engineers; Volume: 01.204; Linguagem: Inglês

10.1299/jmsesdm.01.204.55

2424-2918

Kazunori Hamasaki, Eiji Kinoshita, Hiroshi Tajima, Koji Takasaki, Daizo Morita,

Vehicle emissions and performance

Considerable amount in 400,000 〜 600,000 tons per year of waste vegetable oil in Japan is still flushed down the drain. Utilization of waste vegetable oil for diesel fuel leads to two advantages for environmental protection, to reduce CO_2 emission from engines and to avoid water pollution of rivers. In this study, combustion characteristics of waste vegetable oil methyl ester (WME) are in detail investigated by not only engine test run but also observation of burning flames in a visual engine. In order to reduce NOx emission of WME, emulsified waste rapeseed oil methyl ester (EME) also is tested. Engine test run shows that smoke emission from WME is lower than gas oil, that thermal efficiency of WME is the same as gas oil, and that NOx from WME is about 13 % higher than gas oil at full load. Though CO and HC emissions from WME are higher than from gas oil, absolute values of them are acceptable. According to the results, it is concluded that WME can be used for diesel engines instead of gas oil. Figure 1 shows the effects of water in EME on the emissions and thermal efficiency at full load. Paying attention to the point of 15 % water content, 18 % of NOx reduction is carried out accompanied by some reduction of smoke emission. Thermal efficiency is also successfully 4.5 % improved with 15 % water content. Figure 2 shows the heat release rate of EME with 15 % water compared with WME and gas oil. As EME contains water, larger quantity of EME must be injected than other two fuels to release the same heat. So, injection duration of EME is longer than the others. And, EME starts to burn later than other two fuels because of longer ignition delay. However, combustion end of EME is not later than the others, which means the burning speed of EME spray is higher. To investigate in detail the improvement of combustion by applying EME, visual study of burning flames is carried out and the photos are introduced in the full paper. According to such investigations, it is considered that the reduction of soot formation and the faster combustion after the end of injection with EME is achieved by improving air entrainment into the spray.