Abstract
This study changed intake valve timing for improving knocking limit on the Spark Ignited Engine fueled with mixture of DME and LPG, which has much reality in the future because of the fact that DME requires a similar supplying infrastructure for LPG. 1-D simulation tool and a knocking model were employed to intake valve timing optimization. The simulated solution was checked on the real engine and exhaust emission was measured and compared with that from previous valve timing.