Abstract
To improve the performance of alcohol engine, concrete methods for materializing pulverization and vapourization of fuels and their effects were studied experimentally. The results are as follows.
(i) The method of changing thickness of heating plate, in which whole exhaust gas passes through heating chamber, is suitable for fine adjustment of heating quantity, and the method of changing passing quantity of exhaust gas through heating chamber, in which the thickness of heating plate is kept constant, is suitable for rough adjustment.
(ii)In the method of partial passage of exhaust gas, the characteristics of nozzle are varied not only by its size, but also by its position whether it is located in front or rear of heating chamber. The characteristcs of the former are apt to be influenced by throttle valve opening, and the latter by engine speed.
(iii) By adjusting the combination of heating quantity and ignition timing optimum to get the maximum output, it is turned out that ignition timings for ethanol should be advanced by 6.8° and 4.8° respectively, compared with the ones for gasoline which is and is not pulverized and vapourized.
(iv) Using the same engine under the same operating conditions, such as throttle valve opening, engine speed, and weight of inhaled air at theoretical air-fuel ratio, tests were executed using ethanol and gasoline, which were and were not pulverized-vapourized, and adjusting the combination of heating quantity and ignition timing optimum for the maximum output.
The results are as follows.
(a) By the pulverization-vapourization method, output and thermal efficiency are increased both in ethanol and gasoline, and the toxic compounds in exhaust gas, especially NOx, are decreased.
(b) Without pulverization-vapourization, ethanol is not superior to gasoline, but by pulverization-vapourization method, ethanol becomes to be superior to gasoline in both engine performance and cleanliness of exhaust gas.
(c) As the fuel consumption and evaporation heat of ethanol are far higher than gasoline or kerosene, it will be effective to control heating quantity and ignition timing in accordance with throttle valve opening and engine speed.
