Toyota Lean Combustion System - The Third Generation System

Controlling spark timing for consecutive cycles to reduce the cyclic variations of SI engines

“…The objective is to determine the optimum value of the current spark timing as the system input u(k), which minimizes the cost function Eq. (13). In this study, d¼1 since the current spark timing value from controller affects in the one step ahead cylinder combustion cycle's only.…”

“…The cyclic variations appear in the consecutive cylinder pressure cycles even though the spark timing and other control parameters are constant. These variations reduce the power output of the engine, involving incomplete burns or even total misfires, leads to increased hydrocarbon emissions, operational instabilities, results in undesirable engine vibrations and noise, and may even cause the engine to stall [13]. Reducing the cyclic variations is an effective method to improve the fuel economy and the performance of SI engines.…”

The effect of combustion chamber shape on cylinder flow and lean combustion process in a large bore spark-ignition CNG engine

“…Turbulent models are some certain relational expressions associated the turbulent fluctuating and the time-average. keε model is a most widely applied turbulent model in the engineering calculation [19].…”

Cyclic moving average control approach to cylinder pressure and its experimental validation

“…Furthermore, the cyclic imbalance is also a cause damaging exhaust emission performance. As shown in [2], when an engine runs in lean situation, 30% of the emission can be reduced if the engine runs without cyclic variability. However, the cyclic variation of in-cylinder pressure profile, as a result of the combustion process in each cycle, is an unavoidable natural phenomenon with chaotic property [3].…”