Effect of EGR on performance and operation range of methanol HCCI engine

In order to solve the problem that the operation range of homogeneous charge compression ignition (HCCI) is too narrow, an external exhaust gas recirculation (EGR) system was installed on the HCCI engine. By adjusting EGR ratio, intake charge temperature and mixture concentration, the impacts of external EGR on methanol HCCI engine performance and operation range were investigated under different operation conditions. The results show that EGR does have remarkable influence on performance and operation range. External EGR can extend the mixture concentration toward richer mixture. The indicated mean pressure is increased by 35.14%, from 0.37 MPa without EGR in 0.50 MPa with EGR. Also, the indicated mean pressure range is effectively extended and the maximum changeable range, about 0.22 MPa, is obtained when EGR ratio keeps between 12% and 15%. 1 tab, 6 figs, 11refs.