On the Effects of Intake Pipe System in a Small Two-Stroke Cycle Gasoline Engine : 2nd Report, The Effect of Position of a Carburetor

Abstract

In the previous paper, the authors reported already the effects of length of an intake pipe on the delivery ratio in a small two-stroke cycle engine, and in the experiments they found that as a carburetor was put near an inlet port, the combustion in cylinder became worse. Then they have carried out some experiments with an intake pipe of constant length in order to examine the effect of position of the carburetor on the engine performances. Some results obtained are summarized as follow : a) In general, the nearer the carburetor to the inlet port, the worse becomes the combustion state in cylinder. b) With an intake pipe of constant length, the delivery ratio (K) is little affected by the position of carburetor in the pipe system. c) When the carburetor is inserted fairly close to the inlet port, the fuel level in float chamber fluctuates violently and the fuel consumption decreases considerably more than the case of the normal running. d) The poor combustion or occurrence of missfiring is caused by the lack of fuel, which depends largely on the amplitude of pulsation wave in the intake pipe and is partly governed by the matching condition between the period of the pulsation wave and the open-timing of inlet port. e) If the carburetor is set up at the entrance of intake pipe, the combustion state is satisfactory in all range of engine speed, because the amplitude of pulsation wave is so small that the fuel flow is little affected by it.