From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Analysis of heat loss from the crankcase and the effect of reduced oil flow on engine temperatures.
| Identifier | ExFiles\Box 69\4\ scan0359 | |
| Date | 19th October 1927 guessed | |
| contd :- -2- lost heat to the jackets. Light spring indicator diagrams of compression and expansion, without firing, shew that the air, or medium used, gains heat from the cyl. walls. Referring to the experiment shewing the variation of heat given to the oil with the rate of flow through the bearings, it will be noticed the crankcase temp. is higher with the smaller flow as would be expected. Naturally the higher the temp. of the crankcase the more heat it will dissipate, consequently it may be suggested that the reduction in heat flow measured was due to the greater radiation from the crankcase. Let us assume the rate of heat dissipation from the crankcase to be proportional to the temp. difference between the crankcase and the surrounding air and take the figure of 6.2% for the proportion of the heat lost through the crankcase. This figure it will be remembered was estimated from previous tests. On this assumption, increasing the crankcase temp. from 82°C. to 90°C with an air temp. of 20°C would increase the crankcase loss from 6.2% to 7% or less than 1%. The reduction in heat flow to the cooler with the reduced flow amounted to 19.6%, therefore it would appear that the increased radiation from the crankcase with the reduced flow would not appreciably affect the result. We hope to be able very soon to supply further results of tests with reduced capacity oil pump and experiments with guards on the bottom of the pistons to prevent oil being thrown on to the crown. Hs{Lord Ernest Hives - Chair}/A.C.Lovesey. | ||