Search Results

Momentary flywheel speed is the most convenient signal to detect cylinder-by-cylinder variations. Though some papers had indicated that torsional vibration of crankshaft should be considered at high-speed condition [1][2][3], it is still not very clear how to quantitatively analyze the influence of the vibration upon the flywheel speed. The goal of this paper is to reveal the influence and to find a way to compensate it. At first the transform functions of each cylinder torque to flywheel speed are analyzed. Then based on the transform functions, rigid crankshaft model and flexible crankshaft model are compared. The influence of the torsional vibration on the flywheel speed is investigated. Finally, a compensator of the influence is built. The compensator is verified by the simulation results. After compensation, the measured flywheel speed can be processed under the rigid crankshaft model.

Cylinder-by-cylinder variation control is an important issue to the solenoid-based electronic diesel engines. Large variation causes bad engine performance and should be avoided. This paper presents the research results achieved by the author on the issue of cylinder-by-cylinder closed-loop feedback control of diesel engines. Momentary flywheel speed is processed to estimate the cylinder-by-cylinder variation. Utilizing a special signal modulation technique, the new cylinder-by-cylinder variations detection algorithm is worked out, which has a good adaptive capability to fluctuation characteristics of the momentary flywheel speed under variant operating conditions. This algorithm extends the variations detection range from the low speed and steady state engine conditions to the whole engine steady operating condition of the engine and some transient conditions. The closed-loop control of the cylinder-by-cylinder variation is carried out on the engine test bench.