GASOLINE AND ALCOHOL ENGINE TESTS

GASOLINE AND ALCOHOL ENGINE TESTS

The United States Geological Survey has just issued a bulletin on “Commercial Deductions from Comparisons of Gasoline and Alcohol Tests on Internal-Combustion Engines,” by Robert M. Strong. The tests, which were under the technical direction of R. H, Fernald, engineer in charge of the producer-gas section of the technologic branch, were conducted at the fuel-testing plant in St. Louis, Mo., and at Norfolk, Va. The tests dealt primarily with gasoline, forming part of the investigation of mineral fuels provided for by acts of Congress. To determine the relative economy and efficiency of gasoline it was compared with denatured alcohol. When the series of tests was started, it was found that it took from one and one-half to two times as much alcohol as gasoline to produce a given power. W ith special alcohol engines, entirely suited to the use of alcohol, the latter fuel has been made to do as much work, gallon for gallon as the gasoline. On this point, the bulletin states: “By using alcohol in an alcohol engine with a high degree of compression (about 180 pounds per square inch above atmospheric pressure much higher than can be used for gasoline on account of preignition from the high temperatures produced by compression) the fuel consumption rate in gallons per horsepower per hour can be reduced to practically the same as tile rate of consumption of gasoline for a gasoline engine of the same size and speed. The indications are that this possible t to I fuel consumption, ratio by volume, for gasoline and alcohol engines, will hold true for any size or speed, it the cylinder dimensions and revolutions per minute of the two engines are the same.” Some of the more important results and conclusions stated in this bulletin are as follows: The low heating value of completely denatured alcohol will average 19.500 British thermal units per pound, or 71.900 British thermal units per gallon. The low heating value of 0.71 to 0.70 specific gravity gasoline will average 19.200 British thermal units per pound, or 115,800 British thermal units per gal Ion. The low heating value of a pound of alcohol is approximately six tenths of the low heating value of a pound of gasoline. A pound of gasoline requires approximately twice the weight of air for complete combustion as a pound of alcohol. A gasoline engine having a compression pressure of 70 pounds but otherwise as well suited to the economical use of denatured alcohol as gasoline, will, when using alcohol, have an available horsepower about It) per cent, greater than when using gasoline. When the fuels for which they are designed are used to an equal advantage, the maximum available horsepower of an alcohol engine having a eompres sion pressure of 1st pounds is about ;tll per cent, greater than that of a gasoline engine having a compression pressure of 7t> pounds, but of the same size in respect to cylinder diameter, stroke and speed. Alcohol diluted with water in any proportion, from denatured alcohol, which contains about Id per cent, of water, to mixtures containing about as much water as denatured alcohol can be used in gasoline and alcohol engines if they are properly equipped and adjusted. W hen used in an engine having a constant degree of compression, the amount of pure alcohol required for any given load increases and the maximum available horsepower of the engine decreases with a diminution in the percentage of pure alcohol in the diluted alcohol supplied. The rate of increase and decrease respectively is such, however, that the use of 80 per cent, alcohol instead of 90 per cent., or denatured alcohol, has hut little effect upon the performance of the engine: so that if 80 per cent, alcohol can be had for 15 per cent, less cost than 90 per cent, alcohol and could be sold without tax when denatured, it would lie more economical to use the 80 per cent, alcohol. The relative hazard involved in the storage and handling of gasoline and denatured alcohol is of particular importance in considering their use as fuels for marine and factory engines and engines to be placed in the basements of office buildings, in coast defense fortifications, or in like places where a general lire would be likely to result from the accidental burning of the fuel stored or carried for immediate supply, or where the forming of explosive or inflammable mixtures of the fuel vapors and air in the immediate vicinity would be hazardous. It is indicated by statistics and is also the general consensus of opinion of those experienced in handling gasoline kerosene, and possibly less than in the use of kerosene, but as yet the relative lire risk has not been definitely established. Considerable work has been done on this phase of the investigation and a series of tests that will be ol assistance in determining the relative hazard involved in the use of these fuels is in progress at the testing station of the Survey in Pittsburg. In regard to general cleanliness, such as absence of smoke and disagreeable odors, alcohol has many advantages over gasoline or kerosene as a fuel. The exhaust from an alcohol engine is never clouded with a black or grayish smoke, as is the exhaust of a gasoline or kerosene engine when the combustion of the fuel is incomplete, and, it is seldom, if ever, clouded with a bluish smoke when a cylinder oil of too low a fire test is used or an excessive amount supplied, as is so often the ease with a gasoline engine. The odors of denatured alcohol and the exhaust gases from an alcohol engine are also not likely to be as obnoxious as the odor of gasoline and its products of combustion. Very few alcohol engines are being used in tile United States at the present time, and but little has been done toward making them as adaptable as gasoline engines to the requirements of the various classes of service. Engines for stationary, marine, and traction service, automobiles, motor trucks, and motor railway cars designed especially to use denatured alcohol have, however, been tried with cotisidcrable success. The price of denatured alcohol is greater than the price of gasoline, and the quantity of denatured alcohol consumed by an alcohol engine as ordinarily constructed and operated is in general relatively greater than the quantity of gasoline consumed by a gasoline engine of the same type. Considerable attention is being given to the development’ of processes for the manufacture of alcohol from cheap raw materials which are generally available, and it seems reasonable to expect that the price of denatured alcohol will eventually become as low or lower than tile price of gasoline, especially if the price of gasoline advances. It also seems reasonable to expect a greater general improvement in alcohol engines than in gasoline engines. When used as a fuel denatured alcohol is not always so classed as to be exempt from restrictions placed on the use of gasoline by tile rules of insurance and transportation companies or city ordinances. The restrictions that are placed on the use of denatured alcohol are, however, never greater than those placed on the use of gasoline. In some places, they are such that the use of an alcohol engine is permitted where the use of a gasoline engine is prohibited. Eor instance, alcohol motor trucks, and* automobiles are admitted to many of the steamer piers in New York that are not open to gasoline machines. When the restrictions placed upon the use of denatured alcohol are less than those placed on the use of gasoline or where safety and cleanliness are important requisites, the advantages to be gained by the use of alcohol engines in place of gasoline engines may bt such as to overbalance a considerable increase in fuel expense, especially if the cost of a fuel is but a small portion of the total expense involved, as is often the case. Denatured alcohol, will, however, probably not be used for power purposes to any great extent until its price and the price of gasoline become equal and the equality of gasoline and alcohol engines in respect to service required and quantity of fuel consumed per brake horsepower, which lias been demonstrated to be possible, becomes more generally realized. A further general development in the design and construction of engines that use kerosene, or cheaper distillates, and the crude petroleums may lie reasonably expected and may delay the extensive use of denatured alcohol for some time to come, but as yet comparatively few data pertaining to this phase of the general investigation are available.

At a recent fire at Kingsbridge Terrace, New York City, nearly at the top of the hill, on which the Jerome Park reservoir is situated, the firemen were greatly handicapped by the low water pressure. The streams carried no higher than the top of the first story, and finally, the new iron fence surrounding the reservoir was broken down and the firemen pulled an engine to the top of the embankment to pump water directly from the reservoir.

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