Using auto-ignition to improve the cycle-to-cycle variations of a small two-stroke engine

Cycle-to-cycle variations occur frequently in small two-stroke engines as a result of irregular combustion and misfire due to the presence of the charge with incorrect air to fuel ratio and burnt gas adjacent to the spark plug. Under normal operating conditions burnt gasses inhibit the flame propagation that initiates from the spark plug. In this paper auto-ignition has been investigated as a means of overcoming the above problem by converting the presence of burnt gas from a disadvantage to an advantage. Under the current investigation trapping exhaust gas using a butterfly valve installed in the exhaust manifold was adopted as a method of realising auto-ignition in a small single cylinder two-stroke engine. Within the operating region of auto-ignition a significant reduction in cycle-to-cycle variations was achieved.