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).
Page detailing the spark settings, power absorption, and cooling system for a 'C. F. R.' engine, including a carburetor diagram.
| Identifier | ExFiles\Box 27a\4\ Scan073 | |
| Date | 1st November 1931 | |
| 118 REFINER AND NATURAL GASOLINE MANUFACTURER NOVEMBER, 1931 ignition circuit, thus causing the neon tube to light each time the spark is fired. The proper spark settings for the “C. F.{Mr Friese} R.{Sir Henry Royce}” engine at different compression ratios are as follows: Compression Ratio 4 ........................................... 29.5 5 ........................................... 22.5 6 ........................................... 18 7 ........................................... 15 8 ........................................... 13 In the case of “C. F.{Mr Friese} R.{Sir Henry Royce}” engines fitted with magneto ignition, advantage has been taken of the possibility of automatically adjusting the spark to correspond with compression-ratio setting by means of a cable linkage connecting the magneto-advance lever with the cylinder block. This is shown best in Figure 1. [DIAGRAM OF A FOUR-BOWL CARBURETOR] FIGURE 7 Plan View of “C. F.{Mr Friese} R.{Sir Henry Royce}” Carburetor Four-Bowl or Routine-test Type THE COOLING SYSTEM Water is the cooling medium used for making knock tests of automobile fuels. The water leaving the cylinder block is not passed through a conventional radiator and cooled, but is returned to the cylinder jacket uncooled. The water is allowed to boil in the cylinder jacket, the steam is then separated from it in a reservoir at the base of the cooling unit below the cooling coil. Both the inlet to and the outlet from this reservoir are below the cooling coils. The steam which separates in this reservoir rises and is condensed by the coil at the top of the unit through which tap water circulates (see Figure 4, side section, at the top), and the condensed water returns to the system at substantially boiling temperature. This type of cooling system holds a substantially constant jacket temperature, and provides the advantages of both the evaporative and the circulated liquid systems of cooling. Adequate circulation of water in the system is insured by a pump inserted between the cooling unit or steam separator and the inlet to the cylinder jacket. This pump, which is driven at twice engine speed by a V-belt from a pulley in front of the fly wheel (see Figure 4, side section), is of modified centrifugal type, and circulates seven gallons of water per minute at 600 r.{Sir Henry Royce} p. m.{Mr Moon / Mr Moore} THE POWER-ABSORBING MEDIUM The power produced by the engine is absorbed by an electric motor which runs as a motor for starting the engine and as a generator feeding back into the line for absorbing the output of the engine when it is running under power. The motor used is a slotted-rotor type induction motor, which runs at substantially synchronous speed, and thus automatically operates either as a motor or as a generator as required in order to hold the engine at a practically constant speed of 600 r.{Sir Henry Royce} p. m.{Mr Moon / Mr Moore} Maintenance of the essential item of uniformity of speed thus requires no attention on the part of the operator. Connection between the engine and the power-absorbing motor is by means of twin V-belts running from the fly wheel of the engine to pulleys on the motor. These belts possess a sufficient amount of elasticity to take up the torque reaction of the engine without transmitting undue strain through to the generator. The induction motor used is of 3½ hp. nominal capacity, and it runs at some multiple of the engine speed of 600 r.{Sir Henry Royce} p. m.{Mr Moon / Mr Moore}, the magnitude of which multiple depends upon the number of cycles of the alternating current available. Proper connection between the induction motor and the engine to maintain an engine speed of 600 r.{Sir Henry Royce} p. m.{Mr Moon / Mr Moore} is made by using a pulley of suitable size on the induction motor shaft. The manner of putting the induction motor into the assembled apparatus is shown in Figure 1 and 2. THE DIRECT-CURRENT GENERATOR To furnish direct current for the ignition system (if battery-type ignition is used), and also for the bouncing-pin circuit, a small 110-volt generator of 0.22 kilowatt nominal capacity is used. As may be seen in Figure 1, it is mounted directly above the induction motor and is driven by a V-belt from a pulley on the induction motor shaft. The voltage of this generator is kept at 110 by means of a hand-adjusted field rheostat. INSTRUMENTATION The instrument used for indicating degree or intensity of knock is the bouncing-pin indicator. With the bouncing-pin element may be employed either a gas-evolution burette or a knockmeter, as preferred. Figure 8 is a sectional drawing of the bouncing-pin element proper. The electrical circuits employed with it are given in the complete wiring diagram. | ||