FRICTIONAL LOSSES IN INTERNAL COMBUSTION ENGINES. 
Comparison of distribution of friction in three internal combustion 
engines. 
‘ National | Crossley | Victor 
Parton Bingine. 40 H.P. | 30 HP. | 6 HP. 
Main'bearings ...  » ... 1b HOM Gay 
Lay shaft and valve gear 2 ‘L 1:5 
Gas friction 34 37 37 
Connecting rod ...° 4 3°5 5 
Piston 45 40 45 
513 
From the last table it is seen that even with different 
types of engines there is such a general agreement in the 
percentage of friction allotted to each part of the engine 
that one is justified in drawing up a general table to show 
in round figures the average distribution of frictional losses 
in internal-combustion engines. Such a table is given below 
Distribution of friction in internal-combustion engines. 
Part of Engine. Per Cent. Distribution. 
Piston 45 
Gas friction ... 35 
Main bearings 14 
Connecting rod Je zp | 4 
Lay shaft and valve gear ... 3 
In concluding one might draw attention to the large loss 
under the title of ‘“‘gas friction.’”’ From Fig. 2 is seen how 
rapidly this increases with the velocity of the engine, and 
conversely how greatly it is diminished by reducing the 
speed of the engine or, what comes to the same thing, the 
speed of the gas through the passages. It seems, there- 
fore, that valves could, with advantage, be increased still 
more in size even at the risk of mechanical difficulties. 
To sum up, the retardation method offers the advantages 
ofaccuracy and complete speed range with the disadvantage 
Gea—December 2, 1914. 
