Individual Cylinder Control of Diesel Engines

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. The experimental results verified not only the feasibility, reliability and accuracy of the whole control system, but also its effectiveness in improvement of engine performance such as fuel consumption, smoke emission and so on.