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).
Continued report on experiments concerning engine oil temperature, circulation, and the effects of compression ratios on pistons.
| Identifier | ExFiles\Box 69\4\ scan0357 | |
| Date | 19th October 1927 guessed | |
| contd :- -4- of 10% total oil circulation may account for some of the heat added to the oil but we have not observed at the most more than one half a degree C. between the inlet to the pump and the feed to the bearings. Certainly the pipes during these tests were exposed and some cooling may have taken place but even so we do not think the rate of circulation of the oil pump can seriously affect the temp. of the oil. We propose to make a careful test of this point and also test a pump with the capacity reduced by one-third as suggested. We are about to test some pistons having alum. covering plates to prevent oil splashing up to the hot crown as we think this may result in less heat being picked up by the oil even with a plentiful supply through the bearings. We do not think the high compression ratio heats more oil than a low ratio. Actually from some tests done on the Phantom we found a higher ratio resulted in less heat flow to the water which would indicate a cooler piston. We have also seen reports of other tests - viz: a paper before the Institute of Mechanical Engineers on Piston Temperatures by Prof. Gibson which shew that usually high compression ratios give cooler pistons. The above initial experiments shew some of the chief sources where the oil obtains its heat but when further experiments are completed we hope to give a complete summary of all the factors and the extent to which they contribute to heating the lubricating oil. Hs{Lord Ernest Hives - Chair}/A.C.Lovesey. | ||