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).
Recommended practice document for conducting engine knock tests.
| Identifier | ExFiles\Box 27a\4\ Scan075 | |
| Date | 1st November 1931 | |
| 124 REFINER AND NATURAL GASOLINE MANUFACTURER NOVEMBER, 1931 that registers on the scale of the knockmeter (see Figure 10). Instructions for the operation and care of the bouncing-pin indicator are given in Appendix II. CONTROL PANEL A control panel placed in a position convenient for the operator, as shown in the photographs, Figure 1 and 2, carries the following: gas-evolution burette; knockmeter (if used); voltmeter and field rheostat for the direct-current generator; engine oil-pressure gage; and the switches necessary for starting, for stopping, and for controlling the ignition and the instrumentation. APPENDIX II Tentative Recommended Practice for Making Knock Tests 1. INTRODUCTION The following practice for determining octane numbers* of motor fuels is suggested for the purpose of obtaining uniformity in the industry. It represents one of several methods, and has been selected because, in the light of our present knowledge and experience, it is the one which is most likely to give reproducible results. The equipment mentioned has been built especially for this purpose, and is recommended as being the best available for the purpose at this time. It is recognized that, as our knowledge of the art increases, changes will necessarily be made in both equipment and technique, and, therefore, the following practice is subject to revision. The present practice should not be applied to aviation fuels, which will be treated as a separate subject at a later date. 2. APPARATUS The apparatus to be used for determining octane numbers of motor fuels is composed of an engine, a method of loading, and control equipment to bring the apparatus to fixed operating conditions, together with suitable accessories to supply fuels under test to the engine and measure the resultant knock intensity. The engine recommended is that developed especially for this purpose by the Cooperative Fuel Research Steering Committee and manufactured by the Waukesha Motor Company, of Waukesha, Wisconsin. References to "the engine" will be understood to mean the engine with variable compression ratio and integral head which will be called the "C. F.{Mr Friese} R.{Sir Henry Royce}" engine. Loading and accessory equipment is furnished as a unit with the engine. This includes a cast-iron base on which is mounted the engine, the power-absorbing medium, and the panel board. Essential control equipment, instrumentation, switches, etc., are suitably mounted. The carburetor was designed especially for this engine, and may be ordered with either two or four float bowls as desired. The knock-measuring device is a bouncing pin, coupled with either a gas-evolution burette or a knockmeter, as preferred.† 3. FOUNDATION The foundation, if possible, should be poured on a concrete floor, and should have a height of at least 18 inches. Proper dimensions will be furnished with the engine. For convenience in operation, the foundation should be placed at least two feet from any wall. Should the floor of the building in which an engine is to be installed be other than portland cement, the floor should be cut away so that the engine foundation will rest directly on the ground. In such case, the depth of foundation should be increased to give ample footing, depending upon the condition of the underlying soil. 4. ENGINE CONTROL Start the electric motor by means of the push-button switch. With the engine being turned over by the motor, turn on the ignition and set a carburetor cock so as to draw gasoline from one of the float bowls. To stop the engine, turn off the fuel and ignition switch, and stop the motor by means of the push-button switch. 5. STANDARD ADJUSTMENTS a.{Mr Adams} Engine speed, 600 r.{Sir Henry Royce} p. m.{Mr Moon / Mr Moore} b. Jacket temperature, boiling water. c. Cooling water, distilled or rain water. d.{John DeLooze - Company Secretary} Crankcase oil, S. A.{Mr Adams} E.{Mr Elliott - Chief Engineer} No. 20. e.{Mr Elliott - Chief Engineer} Valve clearances, as recommended by manufacturers. f.{Mr Friese} Spark advance, maximum power (automatically adjusted). g.{Mr Griffiths - Chief Accountant / Mr Gnapp} Breaker-point clearance, 0.018 to 0.022 in. h.{Arthur M. Hanbury - Head Complaints} Spark plug, as recommended by manufacturers.‡ i. Spark-plug gap, 0.025 in.‡ 6. REFERENCE FUELS The primary reference fuels to be used are those approved by the S. A.{Mr Adams} E.{Mr Elliott - Chief Engineer} Standards Committee: iso-octane (2, 2, 4-trimethyl pentane) and normal heptane. In view of the expense and limited supply of heptane and octane, it is expected that individual *Octane number is numerically the percentage by volume of iso-octane (2, 2, 4, trimethyl pentane) in a mixture of iso-octane and normal heptane. The octane number of a fuel is the octane number of the mixture of iso-octane and normal heptane which it matches in anti-knock value. NOTE.—As it appears probable that future developments may result in fuels approaching pure octane in anti-knock value, or even exceeding it, pure octane would have an octane number of 100, and the scale can be extended above this point by such a secondary definition as "octane number" above 100 are defined as 100 plus the percentage of pure benzine (C⁶H⁶) in iso-octane-bengene mixtures." This may be considered as looking too far into the future, but any scale adopted should be capable of ind-finite extension without abandoning the scale for the fuels of the present. See S. A.{Mr Adams} E.{Mr Elliott - Chief Engineer} Handbook, p. 550. Throughout this statement where the word "octane" is used, the reference is to iso-octane (2, 2, 4, trimethyl pentane). | ||