Low-speed hunting of the pneumatically governed compression ignition engine. Effects of various parameters on the amplitude and frequency of limit cycle.

Abstract

For a better understanding of hunting, it is desirable to obtain the amplitude and frequency of limit cycle analytically. In the author's last two reports, as a first step toward nonlinear approximate analysis, the effects of individual parameters of a closed-engine-governor system on the instability of the equilibrium state, especially on the frequency and increment of amplitude, were linearly estimated. In the present report, results show that the limit cycle disappears over the whole speed range if the moment of inertia of the crankshaft system exceeds 1.8 times that in the actual engine; this phenomenon resembles the disappearance due to minimized subventuri pressure lag. Results also show that the amplitude decreases, except at extremely low speeds, with decreasing mass of the governing system, although mass reduction is difficult in reality. Further, it is found that the limit cycle does not disappear no matter what value the damping of the governor may take.