Abstract:

The swelling performance of rubbers in blends of diesel and polyoxymethylene dimethyl ethers (PODE) was studied to solve the sealing problem when using PODE in diesel engines. Five diesel-PODE blends with 0%~40% PODE were selected as fuel samples and five kinds of normal rubbers and a special rubber
perfluorinated elastomers (FFKM) were selected as sealing materials. Immersion method was used to study the swelling performance. The results show that both mass and diameter of each rubber change in the same trend. The mass of rubbers increases quickly in the initial stage of immersion and then keep stable, and decreases slowly finally. Under the fuels with the same PODE blending ratio, the mass change ratio of ethylene propylene diene monomer (EPDM) is the biggest and then in sequence of silicon rubber (QR), fluororubber (FKM), nitrilebutadiene rubber (NBR) and hydrogenate nitrile (HNBR). The mass change ratio increases as PODE blending ratio rise for all normal rubbers except EPDM. The mass change ratio decreases as PODE blending ratio rises for EPDM. Diethyl-ether and alcohol-ether type additive could restrict the swelling a little, only lower than 10%.FFKM could solve the swelling problem of diesel-PODE blends well.

Key words: blended fuel, diesel fuel, polyoxymethylene dimethyl ethers (PODE), rubber, swelling