Studies on the Density of Exhaust Gas on Farm Engines (No. 1)

Abstract

The effect of the moving conditions of the aircooled 2 cycle gasoline and the water-cooled 4 cycle diesel engine upon the smoke density of exhaust gas was investigated, and the following results were obtained.
(1) The smoke density of exhaust gas reaches the maximum soon after started, thereafter decreases suddenly and then very slowly.
(2) In the diesel engine the smoke density increases with the increment of r. p. m., while the 2 cycle engine reduces beyond the certain limit of r. p. m., The density is higher at the loads of 1/4 and 4/4, and lower at the intermediate loads of 2/4 and 3/4.
(3) The smoke density increases with the increment of the ratio of mobile oil to gasoline of the 2 cycle and the ratio of heavy oil to light oil of the diesel, but the variation of the density of the diesel is too slight to be measured with the eye.
(4) So far as the 2 cycle engine is concerned, the longer the idling period is, the more the smoke density increases within the certain limit of time.
(5) The smoke density increases in proportion to the increment of the diameter of leakage hole, and in this case the degree of increasing of the density of the 2 cycle is higher than that of the diesel.
(6) A spark plug with high heat value results in the higher smoke density at the lighter load, and on the contrary, a plug with low heat value at the heavier load.
(7) Imperfect atomization of the fuel injected form the nozzle causes the higher smoke density.
(8) The conditions of the piston ring affect the smoke density. The penetration of oil into the combustion chamber and the imperfect combustion due to the gas leakage are considered to be main causes of the higher smoke density.