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).
Description of a rotary valve mechanism and its timing with reference to Figure 3.
| Identifier | ExFiles\Box 147\4\ scan0176 | |
| Date | 13th August 1940 guessed | |
| It is to be understood that the invention is not limited to this particular mechanism for driving the rotary valve, since many other forms of driving con- nection are available and may be used for this purpose. 5 Figure 3 shows a suitable timing for the drive. In this Figure, 20 is the locus of the pin 18, while 21 and 22 are the axes of the arm 14 and wheel 15 respectively. The heavy lines show the position of the arm 14 at the opening and closing of the inlet and exhaust 10 ports, and the lines radial to 22 show the corresponding positions of the slot 16 on the wheel 15. When the piston in the cylinder containing the valve 10 is at its top dead-centre position and about to make a suction stroke, the centre line of the slot 16 is in the position 15 marked 0° in Figure 3 and is at an angle of 56° to the line through the centres 21 and 22. The wheel 15 will turn at a uniform speed through one revolution during the next two crankshaft revolutions. The inlet-port opens when the wheel 15 is 3° before its 0° position, 20 that is when the crankshaft is 6° before its top dead- centre and remains open while the wheel 15 turns through 118° and the crankshaft turns through 236°. During this period the arm 14 turns at higher speed through an angle of 134°. The average speed of the valve is thus increased 25 in the ratio 134/118 or 1.13/1. It will be noted that the wheel will be in the position 56° to give the maximum velocity ratio at the midpoint of the period during which the inlet port is open. The inlet-port closes at 115° in the rotation of the wheel 15 or 230° in the first 30 rotation of the crankshaft. 5. | ||