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Show Uo So Experimamts Cut Cost of Gas Wjustment of Carburetors on Government Trucks Reduces Consumption of Fuel. Washington. Substantial savings of gasoline by the periodical adjustment of carburetors based on the results of analysis of exhaust gases from automobile auto-mobile engines are said to be feasible by the Department of the Interior following experiments made by the bureau of mines on the lle.-t of motor trucks used by the government fuel yard In Washington. As the result of carburetor adjustments made by gas analysis In the bureau's experiments, an actual Increased cHicIcney in mile-! mile-! age and saving of gasol ne amounting I to L'J per cent was attained. The tesis demonstrate that a portable carbon dioxide Indicator for testing the e::-, e::-, Ikium gaes of a motor vehicle gives a positive indira:lon of the carleireter adjustment, removes nil guesswork of tU' h adjustment and is perteetly feasible feas-ible p:aetiially. 1 Samples of Gas Tes:d. J The go eminent fuel yard trucks . tested by the huie.iu of mines ranged In capacity frail two and u hah to seven and a half tons. Miring the j winter months, when the lemand for ; co;iI Is heavy, from .".o to 'A.') trucks ! are u-ed. Samples of the exhaust g is were taken on the trucks kept m 'service few summer haulin; in order ! to determine the carburetor adjust-! adjust-! ment as used. Chang' s then were j made to a more ei onoinical adjustment adjust-ment wheneer possible, without sacrificing sac-rificing flexibility of operation and lower. In nil but one case the carburetors car-buretors were found to he adjusted too rich for maximum power nnd economy. Increase in Mileage Noted. The actual Increase in mileage ami saving of gasoline due to the earMirc-tor earMirc-tor adjustments made by gas nna!s,s when the month previous ami the month following the iidjus'iiients are compared, showed an Increase In mileage mile-age of per cent ; for the second month after adjustment, Id per cent, land for the third month, '.) per cent. When the mileage is compared truck for truck, ami not taking into consideration consid-eration the distance each traveled during dur-ing the month, the Increased mileage equaled 1! 1.7, 1.2 nnd 10.2 per cent, respectively. The adjustment of carburetors by analysis of exhaust gas Is based upon the fact that the carbon dloxocle In the exhaust Is 11 direct Indication of the air-fuel ratio and completeness uf combustion. In turn, the iilr-fuel ratio and completeness of combustion combus-tion tell whether the carburetor Is properly adjusted for maximum power and gasoline economy. Adjustment Usually Rich. Other conditions being constant, the mileage obtainable varies ns the percentage per-centage of carbon dioxide hi the exhaust ex-haust gas and air-fuel ratio. This has been little realized by most garage men In the past. I'sually the adjustment adjust-ment Is far loo rich for maximum : economy. There are, however, excep- tlons to this rule. A deterndnatlon of the carbon dioxide content of the exhaust ex-haust gas while the vehicle Is being operated on the road gives a positive Indication of the carburetor adjustment. adjust-ment. The results of the bureau of mines experiments show that adjustable carburetors car-buretors tend to become more richly adjusted with lapse of time, nnd that the adjustments should be checked at least every two months to maintain the most economical adjustments. The bureau suggests that one driver may be able to get considerable more mileage than another, due to the method of driving. The mileage Is greatly Increased by disengaging the clutch whenever possible and coasting. coast-ing. In approaching a heavy grade snllieient momentum sliouol lie obtained ob-tained to carry the vehicle a considerable consider-able distance up the g a le before making mak-ing It necessary to change the gears. Weather has a marked effect on the n.i!e;iL'e obtainable. In geti.-ral. a motor mo-tor runs better at higher humidity and temperatures. Kainy weather d'-cieases d'-cieases the mileage on account of the slippery nature of the streets; so docs sllo;y weather. |