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).
Letter from an oil company discussing the anti-knock value and pricing of their Koolmotor Alcohol Blend fuel.
| Identifier | ExFiles\Box 27a\4\ Scan115 | |
| Date | 16th May 1933 | |
| C O P Y From: CITIES SERVICE OIL COMPANY LTD. London 16th May 1933 To: Messrs. Rolls-Royce Ltd, DERBY Dear Sirs, We are in receipt of your letter of the 15th inst. concerning the anti-knock value of our KOOLMOTOR ALCOHOL BLEND. For your information, we determine the anti-knock value of our motor fuels in an Armstrong-Whitworth variable compression engine, the operating conditions of which are very carefully controlled. We have succeeded in establishing a conversion table which reliably translates the results obtained on this engine into octane ratings, and tests carried out recently showed our Koolmotor Alcohol Blend to have an anti-knock value equivalent to 85 octane. However, in view of the fact that certain modifications have just recently been made in the method of determining octane rating by the now universally recognised C.F.R. engine method, we have to-day had carried out tests on one of these engines in accordance with the latest practice. The recent modifications in the method of test concern principally the water jacket temperature which has been increased, and consequently a slightly lower value is to be expected. The result we have obtained to-day is 84 (eighty-four). We should like to point out that in our letter of the 2nd inst. we mentioned that we believed the nearest competitive fuel had an octane rating of 76. On testing this particular grade to-day (a well-known tetra-ethyl lead blend) a reading of 75 octane was obtained. Thus, Koolmotor still shows a superiority in anti-knock value equivalent to nine octane numbers. In the event of your deciding to order a trial delivery of Koolmotor, this marked superiority in anti-knock performance could, of course, be very easily verified in an engine with a compression ratio of, say, six or seven to one. As a matter of fact, we have heard of instances where our alcohol fuel has been used in engines, admittedly of small cylinder bore, having a compression ratio of eight to one without any detonation occurring except at below 1,000 r.p.m. Yours faithfully, P.S. In view of the alteration taking place to-morrow in the prices of motor spirit, we are now prepared to quote you 1/2 1/2d per gallon for our Koolmotor Alcohol Blend, delivered to your works in minimum 250 gallon bulk quantities. | ||