The Autoignition Chemistries of Octane-Enhancing Ethers and Cyclic Ethers: A Motored Engine Study

The differing chemistries controlling autoignition of octane-enhancing ethers and of cyclic ethers have been inferred from stable intermediate species measurements using the motored-engine technique. Species measurements for three octane-enhancing ethers and three cyclic ethers are presented, compared with literature studies, and contrasted with those of the other ethers. The chemical mechanisms responsible for autoignition of both ether classes are detailed, compared, and used to explain the differences in octane qualities of the two ether classes. Chemical interactions resulting from the addition of MTBE to the paraffin 2,3-dimethylbutane were measured, and are discussed in terms of the chemical mechanisms controlling the autoignition of the neat ether and paraffin.