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Gas-engine research in Germany
72
N o t e s a n d Comments.
[J. F. !~
of discharge, under ancient conditions and under present conditions, ~re briefly given. The above features--geographic, topographic and hydrographic--are illustrated by colored charts. The more important ports on the great rivers--t]le Paran'i and Uruguay--are mentioned, and some interesting features in ref~,rence to the velocity of currents, volumes of discharge, etc., are stated. The present and proposed depths in the two rivers and the commercial features are briefly given. The great Rio de la Plata is specially treated. After giving the hydraulic conditions of Argentine, there is a brief description and illustrations of the Andes, and the effect of the mountainous condition of the country upon civilization is briefly described. Having revie~ ed the physical conditions, a r6sum6 of the history of Argen. tine is given, including a brief account of the aborigines in this and other parts of South America, with a very brief review of American ethnology. Tile struggles of the Colonies of Spain to become independent are described, and the influence exerted by the United States during the conflict. The three great heroes of American i n d e p e n d e n c e - - W a s h i n g t o n , Bolivar and San Martin--are compared, and the campaigns and patriotism of the great hero of Argentine, General San Martin, are treated at some length. Following the history of Argentine, the present Argentine isldescribed-its area, its climate, its productions, and, generally, its agricultural, industrial and commercial features ; its telephones, telegraphs, railways, the cable lii:es which reach it, ant1., in fact, all conditions of interest. Following the general description of Argentine is a description of the city of Buenos Ayres, its streets, buildings, water and sewerage works, its exte~sire port-works, and m a n y details of interest. All of which are illustrated by lantern slides. Following the general characteristics of the country and city of Buenos Ayres, there is given a brief r6sum6 of the ocean commerce, which has done so much since the discovery of the country in developing its resources. Several important projects for giving additional facilities, both at Buenos Ayres and elsewhere, are described and illustrated. During the descriptions above stated, there are given comparisons w~th other cities of the world, including those of the United States, as to population, mortaiity, growth and other features. The National Government has recently completed a very important dry dock at one of the more southerly ports of the country, and this is described and illustrated. The lecture closes by some lantern slides of interesting features of the city of Buenos Aytes, and a brief statement of the reasons which have prompted the lecturer to give this lecture in the United States. The lecture will be published in full later on. W.'H. W.
G A S - E N G I N E R E S E A R C H IN G B R M A N ¥ . The Institution of Civil ~nginecrs publishes the following abstract of a report by Bugene Meyer issued in the Zeitschrift des Vereines deutschcr yllgeniture :
Jan., I9O3.3
Notes and Comments.
73
This is the first i n s t a l l m e n t of t h e results of e x p e r i m e n t s of gas-engines carried out at t h e Institute for Technical Physics at the George Augustus University in G6ttingen. T h e e n g i n e employed for t h e research work is a Io horse-power Deutz motor. Both l i g h t i n g and power-gas are to be used. A description is given of t h e engine, power gas p l a n t a n d t h e apparatus to be used for m e a s u r i n g t h e gas, cooling water etc., a n d t h e degree of accuracy to be expected with the measurements. The first questions investigated were c o n c e r n i n g the effects of v a r y i n g amounts of piston lubrication and t h e t e m p e r a t u r e s of t h e cylinder walls. The lubrication was begu n with one drop every 40 seconds, for which t h e mechanical efficiency was o'7o6 , a n d t h e a m o u n t of gas used per b r a k e horsepower per h o u r 823 liters (29 cubic feet), a n d per indicated horse-power p e r hour 582 liters (2oM cubic feet). T h e lubrication was gradually increased until the oil was r u n n i n g in almost a continuous stream. T h e mechanical efficiency h a d risen to 0"79, t h e gas used p e r b r a k e horse-power p e r hour h a d fallen to 648 liters (23"2 cubic feet), and per indicated horse-power p e r h o u r to 512 liters (I8" 3 cubic feet). T h e load on t h e engine was practically t h e same throughout. The great decrease in t h e a m o u n t o f gas used as t h e supply of lubricant was increased is accounted for b y Meyer on the supposition t h a t some of the oil was vaporized in t h e cylinder a n d b u r n e d along with t h e gas. More elaborate experiments were made with t h e same result. I n f u r t h e r e x p e r i m e n t s t h e temperature of the cylinder.walls was varied from I6 ° C. to 7o° C., while t h e oil suppty was very liberal. I n b o t h cases t h e heat value of t h e gas supplied was 2412 W.]E. (9648 B.T.U.) per indicated horse-power per hour. From this it seems possible t h a t even at comparatively low t e m p e r a t u r e s lubricating oil may be burned and contribute to t h e work done on t h e piston. T h e accuracy obtainable with t h e ordinary indicators was specially investigated, and also th e methods of calibrating t h e springs. T h e t e m p e r a t u r e of a n indicator m a y of course vary, a n d it was found in one case t h a t t h e scale of t h e spring altered by 4 per cent. w h e n t h e t e m p e r a t u r e was changed from ordinary room temperature to about 9o° C. T h e dynamical theory of t h e indicator is applied to a few actual cases, a n d a graphic m e t h o d is given b y w h i c h t h e use of a Fourier series to represent the relation between pressure a n d time is avoided. The inertia of t h e ' p a r t s is f o u n d to have little effect. Friction and inaccuracy of fitting in t h e indicator motion are the most i m p o r t a n t factors in distorting diagrams from t h e i r true shape. T h e indicated power of a gas-engine c a n n o t be determined with perfect exactness, and, while in m a n y cases an accuracy of I per cent. m a y be obtained, in others t h e elTors m a y be as m u c h as 2 or 3 per cent.
N o t e s a n d Comments.
[J. F. !~
of discharge, under ancient conditions and under present conditions, ~re briefly given. The above features--geographic, topographic and hydrographic--are illustrated by colored charts. The more important ports on the great rivers--t]le Paran'i and Uruguay--are mentioned, and some interesting features in ref~,rence to the velocity of currents, volumes of discharge, etc., are stated. The present and proposed depths in the two rivers and the commercial features are briefly given. The great Rio de la Plata is specially treated. After giving the hydraulic conditions of Argentine, there is a brief description and illustrations of the Andes, and the effect of the mountainous condition of the country upon civilization is briefly described. Having revie~ ed the physical conditions, a r6sum6 of the history of Argen. tine is given, including a brief account of the aborigines in this and other parts of South America, with a very brief review of American ethnology. Tile struggles of the Colonies of Spain to become independent are described, and the influence exerted by the United States during the conflict. The three great heroes of American i n d e p e n d e n c e - - W a s h i n g t o n , Bolivar and San Martin--are compared, and the campaigns and patriotism of the great hero of Argentine, General San Martin, are treated at some length. Following the history of Argentine, the present Argentine isldescribed-its area, its climate, its productions, and, generally, its agricultural, industrial and commercial features ; its telephones, telegraphs, railways, the cable lii:es which reach it, ant1., in fact, all conditions of interest. Following the general description of Argentine is a description of the city of Buenos Ayres, its streets, buildings, water and sewerage works, its exte~sire port-works, and m a n y details of interest. All of which are illustrated by lantern slides. Following the general characteristics of the country and city of Buenos Ayres, there is given a brief r6sum6 of the ocean commerce, which has done so much since the discovery of the country in developing its resources. Several important projects for giving additional facilities, both at Buenos Ayres and elsewhere, are described and illustrated. During the descriptions above stated, there are given comparisons w~th other cities of the world, including those of the United States, as to population, mortaiity, growth and other features. The National Government has recently completed a very important dry dock at one of the more southerly ports of the country, and this is described and illustrated. The lecture closes by some lantern slides of interesting features of the city of Buenos Aytes, and a brief statement of the reasons which have prompted the lecturer to give this lecture in the United States. The lecture will be published in full later on. W.'H. W.
G A S - E N G I N E R E S E A R C H IN G B R M A N ¥ . The Institution of Civil ~nginecrs publishes the following abstract of a report by Bugene Meyer issued in the Zeitschrift des Vereines deutschcr yllgeniture :
Jan., I9O3.3
Notes and Comments.
73
This is the first i n s t a l l m e n t of t h e results of e x p e r i m e n t s of gas-engines carried out at t h e Institute for Technical Physics at the George Augustus University in G6ttingen. T h e e n g i n e employed for t h e research work is a Io horse-power Deutz motor. Both l i g h t i n g and power-gas are to be used. A description is given of t h e engine, power gas p l a n t a n d t h e apparatus to be used for m e a s u r i n g t h e gas, cooling water etc., a n d t h e degree of accuracy to be expected with the measurements. The first questions investigated were c o n c e r n i n g the effects of v a r y i n g amounts of piston lubrication and t h e t e m p e r a t u r e s of t h e cylinder walls. The lubrication was begu n with one drop every 40 seconds, for which t h e mechanical efficiency was o'7o6 , a n d t h e a m o u n t of gas used per b r a k e horsepower per h o u r 823 liters (29 cubic feet), a n d per indicated horse-power p e r hour 582 liters (2oM cubic feet). T h e lubrication was gradually increased until the oil was r u n n i n g in almost a continuous stream. T h e mechanical efficiency h a d risen to 0"79, t h e gas used p e r b r a k e horse-power p e r hour h a d fallen to 648 liters (23"2 cubic feet), and per indicated horse-power p e r h o u r to 512 liters (I8" 3 cubic feet). T h e load on t h e engine was practically t h e same throughout. The great decrease in t h e a m o u n t o f gas used as t h e supply of lubricant was increased is accounted for b y Meyer on the supposition t h a t some of the oil was vaporized in t h e cylinder a n d b u r n e d along with t h e gas. More elaborate experiments were made with t h e same result. I n f u r t h e r e x p e r i m e n t s t h e temperature of the cylinder.walls was varied from I6 ° C. to 7o° C., while t h e oil suppty was very liberal. I n b o t h cases t h e heat value of t h e gas supplied was 2412 W.]E. (9648 B.T.U.) per indicated horse-power per hour. From this it seems possible t h a t even at comparatively low t e m p e r a t u r e s lubricating oil may be burned and contribute to t h e work done on t h e piston. T h e accuracy obtainable with t h e ordinary indicators was specially investigated, and also th e methods of calibrating t h e springs. T h e t e m p e r a t u r e of a n indicator m a y of course vary, a n d it was found in one case t h a t t h e scale of t h e spring altered by 4 per cent. w h e n t h e t e m p e r a t u r e was changed from ordinary room temperature to about 9o° C. T h e dynamical theory of t h e indicator is applied to a few actual cases, a n d a graphic m e t h o d is given b y w h i c h t h e use of a Fourier series to represent the relation between pressure a n d time is avoided. The inertia of t h e ' p a r t s is f o u n d to have little effect. Friction and inaccuracy of fitting in t h e indicator motion are the most i m p o r t a n t factors in distorting diagrams from t h e i r true shape. T h e indicated power of a gas-engine c a n n o t be determined with perfect exactness, and, while in m a n y cases an accuracy of I per cent. m a y be obtained, in others t h e elTors m a y be as m u c h as 2 or 3 per cent.