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).
Technical discussion on engine carburation, fuel distribution issues, and the effects of low-grade fuels.
| Identifier | ExFiles\Box 50\3\ Scan016 | |
| Date | 24th January 1921 | |
| EP {G. Eric Platford - Chief Quality Engineer} 19/F24.1.21. Continued. 2. Distribution is certainly easily affected by the dimensions of the throttle as mentioned above, and even the bore of the washer joining the induction pipe to the throttle being altered 1 m {Mr Moon / Mr Moore} /m, seriously affects the distribution. We have been very keen on this condition of running, as we are certainly "up against it" so far as obtaining good power at low engine speeds is concerned, as generally speaking, the pre-war engines appear to have an advantage in this respect as confirmed on the road and on the dynamometer. I understand you are experimenting and comparing the effect of pistons and camshafts. If distribution O.K., it is surprising, apart from low engine speeds full throttle, how the carburation remains good at high engine speeds, even under adverse conditions such as poor petrol, cold engine, etc. One can run without water supply to the throttle at all without the distribution or efficiency being affected at high speeds. At the same time, although it is certainly a fact that if the throttle and induction pipe are such as to cause bad distribution, it is found that the application of heat will improve it. I was only able to make a rough test in this direction, and found that if we poured hot water over the "T" joint where the main pipe connects to the trunk pipe of the induction pipe, the distribution was improved, even although fitted with a poor throttle for distribution as explained above. I therefore think the experiments you are making with regard to supplying exhaust jacketting at this joint should be persevered with, as my tests in this direction were only carried out roughly, and without much expense, during our routine production tests (and demonstrated to Mr. Warwick). We certainly find that the carburation at low speeds is seriously affected by low grade motor fuels, and the petrol which we are obtaining is getting slightly worse in this respect. At the same time, we quite appreciate it is the best that can be obtained. We have, however, with cars on test had very bad cases of poor carburation and we have found that the trouble has been due to the car running on low grade motor fuels, which has been caused by paraffin having been accidentally mixed with this fuel whilst the cars were on test. We have been very keen on keeping Wd {Mr Wood / Mr Whitehead} in touch with the quality of the fuel received, so as to keep it to as high a standard as possible. EP. {G. Eric Platford - Chief Quality Engineer} | ||