Evaluation Of Engine Combustion Uniformity Research Based On The Flywheel Data

Crankshaft angular acceleration fluctuations in non-uniformity of each cylinder from the engine caused by uneven torque contribution of each cylinder, the main reason for the non-uniform torque fluctuations is the cycle variation of gas pressure in the same cylinder and each cylinder. The paper analyzes the correlation between the fluctuations of the crankshaft angular acceleration and the fluctuations of the pressure in each cylinder, then determine the indicators and methods which used to assess the non-uniform of engine combustion. The analysis method using flywheel data processing does not affect the engine's combustion process, the test preparation time is short, less test equipment is required, adapted to a wide range and the test cost is low; it can be integrated into the engine control system to monitor and regulate the engine working condition in real-time. So do this, it can improve the engine uniform combustion, thereby increasing vehicle power, economy, NVH characteristics and emission properties.In this paper, MATLAB software is used to process the raw flywheel data that collected by magnetic sensor. Search the zero-crossing point of the raw flywheel data by using a suitable curve-fitting method, Calculate crankshaft angular velocity, then differentiate angular velocity to generate angular acceleration. Apply low-pass filter to both angular velocity and acceleration, then convert the angular velocity and acceleration to angle domain, calculate the relevant statistical parameters of the filtered angular velocity and angular acceleration in angle domain. Analyze the correlation between the relevant statistical parameters of the crankshaft angular velocity and angular acceleration and the engine cylinder pressure parameters, determined the indicators and methods which used to assess the non-uniform of engine combustion.Analyze the non-uniform of engine combustion using the indicators and methods which used to assess the non-uniform of engine combustion. The engine is a 6.2 L eight-cylinder, four-stroke engine, evaluate the combustion uniformity in certain speed, specific load. Then assess the engine's combustion uniformity, power economy and so on, and studied the effects of load on the engine combustion uniformity in the same speed, different load operating conditions.