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).
Complete specification document for an invention related to the cylinders of internal combustion engines.
| Identifier | ExFiles\Box 147\4\ scan0152 | |
| Date | 16th October 1937 | |
| 2 505,895 invention at least one ignition plug is arranged in the combustion chamber as near to the edge of the inlet valve as is conveniently possible. 5 The invention is primarily concerned with engines in which the fuel is mixed with air before introduction into the cylinder as opposed to those in which the liquid fuel is injected direct into the 10 cylinder. With parts arranged according to this invention the throat connecting the combustion chamber with the cylinder need not be so restricted that detonation may occur at high engine speeds, but this 15 may be made of such a size that the gas velocity through it will lie within those ranges at which the risk of detonation is obviated. Dated the 16th day of October, 1937. CLAREMONT HAYNES & CO., Vernon House, Sicilian Avenue, Bloomsbury Square, London, W.C.1, Applicants Solicitors. COMPLETE SPECIFICATION Cylinders of Internal Combustion Engines 20 We, JOHN LÉON EDWARDS, of 43, Handel Street, Derby, and JAMES DENNING PEARSON, of Lyndene, Burton Road, Littleover, Derby, England, both British Subjects, do hereby declare the 25 nature of this invention and in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement :— This invention is for improvements in 30 cylinders of internal combustion engines and applies to that type of cylinder in which there is a combustion chamber arranged in the head of which one portion (herein called “ the inlet 35 portion ”) is arranged wholly or principally above and open to the cylinder bore and contains an overhead inlet valve, another part (herein called “ the exhaust portion ”) lies above and to one side of 40 the cylinder bore and has in its base an exhaust valve, the two portions communicate by a throat portion (herein called “ the throat portion ”) and the top of the cylinder where not open to the in- 45 let portion is covered by a wall normal or approximately normal to the axis of the cylinder. Such a cylinder is hereinafter called “ a cylinder of the type described ”. In using phrases such as “ above ”, 50 “ below ”, “ the base ” etc., throughout this specification we regard the cylinder as occupying a vertical position. This invention has for its object the 55 provision of improvements in engines having cylinders of the said type with a view to getting good volumetric efficiency and particularly avoiding excess of turbulence which may induce detonations. 60 According to this invention the inlet and exhaust portions of the combustion chamber are each (except where interrupted by the throat) approximately circular in plan the head of the inlet valve 65 has a stem parallel to the axis of such bore or inclined thereto in a direction away from the exhaust portion of the combustion chamber the roof of the inlet por- 70 tion being in the latter case inclined so that the depth of this portion increases as it approaches the throat, the minimum cross sectional area of the throat is not less than 0.15 of the cylinder bore area, 75 and an ignition plug is arranged at the side of the inlet valve toward the exhaust portion of the combustion chamber in a position so that the spark or sparks occur at a point or points distant from the 80 nearest point of the perimeter of the said inlet valve not more than 0.3 of the diameter of the cylinder bore. Preferably the proportions of the combustion chamber are within 10 per cent. 85 (up or down) of the respective figures hereinafter stated. The diameter of the inlet portion of the combustion chamber is 0.75 of the diameter of the cylinder bore. 90 The distance of the axis of the inlet portion of the combustion chamber from the axis of the cylinder is 0.2 of the diameter of the cylinder bore. The diameter of the exhaust portion of 95 the combustion chamber is 0.6 of the diameter of the cylinder bore. The distance of the axis of the exhaust portion of the combustion chamber from the axis of the cylinder is 0.92 of the dia- 100 meter of the cylinder bore. The roof of the inlet portion of the combustion chamber may be so much above the cylinder proper that the whole movement of the inlet valve head will 105 take place in the combustion chamber. In this case if the piston has a flat crown and if the valve spring breaks the valve will fall to the limit of its permitted travel, and even if the valve head lies wholly 110 over the cylinder bore and this travel is stopped by a stop on the stem the valve head will not foul the top of the piston. Alternatively the piston may have its crown raised locally to reduce 505,895 3 the volume of the inlet portion of the combustion chamber when the piston is at top dead centre and increase the compression ratio. 5 Two examples of this invention are illustrated in the accompanying drawings in which : Figure 1 is a vertical section through a cylinder head 10 Figure 2 is a section on the line 2—2 of Figure 1; Figure 3 is a plan view of the piston illustrated in Figure 1. Figure 4 is an inverted plan view of 15 the combustion chamber illustrated in Figure 1. Figures 5 and 6 correspond to Figures 1 and 2 showing an alternative arrangement. 20 The figures are diagrammatic. A is the cylinder to which is secured a cylinder head B by means not shown. Inside the cylinder reciprocates a piston B¹. C is the inlet passage controlled by an 25 inlet valve C¹, which is inclined to the axis of the cylinder. The exhaust passage is shown at D, and the exhaust valve at D¹. In the head is a combustion chamber 30 which is considered as being in three parts. Part E in which the inlet valve is situated and which is open to the cylinder is the inlet portion. Part F over the exhaust valve which lies beyond the peri- 35 meter of the cylinder is the exhaust portion. G is the throat portion which joins the other two portions. Except where it communicates with the portion E of the combustion chamber, the 40 top of the cylinder is closed by a wall H which is normal to the cylinder axis. An ignition plug J is arranged in the portion F of the combustion chamber, so that its spark occurs at a point distant from the 45 nearest point of the perimeter of the said inlet valve not more than 0.3 of the diameter of the cylinder bore. In the example shown in Figures 1, 2, 3 and 4 the top of the combustion cham- 50 ber is dome shaped. In the example shown in Figures 5 and 6 the combustion chamber is of rectangular cross-section, the ignition plug J is vertically arranged, the inlet valve C¹ 55 is more inclined and its lower edge lies in the plane of the bottom of the cylinder head but in other respects the arrangement is similar to that shown in the preceding figures. 60 In the arrangement shown in Figures 1 and 2 assuming that the piston has a flat top, even if the inlet valve spring were to break, the valve head would not foul the piston since its whole movement 65 takes place inside the combustion chamber and it will be stopped by a stop on the stem before it falls below the combustion chamber. On the other hand if this advantage is sacrificed the piston 70 may have its crown raised locally, as shown at K to reduce the volume of the inlet portion of the combustion chamber when the piston is at top dead centre and increase the compression ratio. 75 Having now particularly described and ascertained the nature of our said invention and in what manner the same is to be performed, we declare that what we claim is :— 1. An internal combustion engine hav- 80 ing a cylinder of the type described in which the inlet and exhaust portions of the combustion chamber are each (except where interrupted by the throat) approximately circular in plan the head of the 85 inlet valve has a stem parallel to the axis of such bore or inclined thereto in a direction away from the exhaust portion of the combustion chamber the roof of the inlet portion being in the latter case in- 90 clined so that the depth of this portion increases as it approaches the throat, the minimum cross-sectional area of the throat is not less than 0.15 of the cylinder bore area, and an ignition plug is arranged 95 at the side of the inlet valve toward the exhaust portion of the combustion chamber in a position so that the spark or sparks occur at a point or points 100 distant from the nearest point of the perimeter of the said inlet valve not more than 0.3 of the diameter of the cylinder bore. 2. An internal combustion engine as 105 claimed in Claim No. 1 in which the proportions of the combustion chamber are as follows, or at least within 10 per cent. either up or down of the respective figures hereinafter stated. 110 The diameter of the inlet portion of the combustion chamber is 0.75 of the diameter of the cylinder bore. The distance of the axis of the inlet portion of the combustion chamber from 115 the axis of the cylinder is 0.2 of the diameter of the cylinder bore. The diameter of the exhaust portion of the combustion chamber is 0.6 of the diameter of the cylinder bore. 120 The distance of the axis of the exhaust portion of the combustion chamber from the axis of the cylinder is 0.92 of the diameter of the cylinder bore. 3. An internal combustion engine as 125 claimed in Claim No. 1 or 2 in which the roof of the inlet portion of the combustion chamber lies so much above the cylinder proper that the whole movement of the inlet valve head takes place in the 130 combustion chamber. | ||