Engine Idle Combustion Stability Evaluation Using Calibration Parameters

An Experimental Study of Vehicle 1st Order Vibration Improvement at Engine Idle

“…Therefore, the engine is prone to unstable combustion, resulting in the 0.5 th and 1 st order excitation. 16 In addition, except for the powertrain rotational system imbalance, involving the crankshaft, crankshaft vibration damper, dual-mass flywheel (DMF) and clutch, the imbalance caused by misalignment between adjacent components of the powertrain rotational assembly will generate the 1 st order excitation when idling. The excitation coupling of the unstable combustion and the rotational system imbalance also increases the difficulty of analyzing and solving the 1 st order abnormal vibration problem at idle condition.…”

“…Methods for engine combustion stability evaluation include the cylinder pressure fluctuation method 19 and the crankshaft speed fluctuation method. 16,20 The former is a direct assessment method, whilst the latter is an indirect assessment method. Although the crankshaft speed fluctuation method is simpler, it is difficult to separate the influence brought by the rotational system imbalance.…”

“…A quantified measurement method for engine idle roughness was proposed in 15 by using engine brake torque data. 16 introduces an engine combustion stability evaluation method based on certain calibrated parameters to reduce adverse impacts on vehicle idle quality. Besides, methods for isolation or absorption vibration were also studied.…”