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).
Patent specification for improvements to the combustion chambers of internal combustion engines.
| Identifier | ExFiles\Box 147\4\ scan0148 | |
| Date | 21th December 1938 | |
| PATENT SPECIFICATION Application Date: Dec. 21, 1938. No. 37227/38. 525,879 Complete Specification Left: Jan. 20, 1940. Complete Specification Accepted: Sept. 6, 1940. PROVISIONAL SPECIFICATION Improvements in or relating to the Combustion Chambers of Internal Combustion Engines I, WILLIAM ARTHUR ROBOTHAM, of Park Leys, Duffield, near Derby, England, a British Subject, do hereby declare the nature of this invention to be as 5 follows:— This invention is for internal combustion engines and applies to internal combustion engines having a combustion 10 chamber, the walls of which are not in symmetrical continuation of the walls of the cylinder but in which the wall of the cylinder in one or more places forms a projection normal or approximately nor- 15 mal to the axis of the cylinder and extending over at least one sixth of the cross-section area of the cylinder. A cylinder with a combustion chamber so formed is hereinafter called “ a cylin- 20 der of the said type.” This invention has for its object to increase the compression ratio in the combustion chambers of cylinders of the said type while avoiding serious detonation. 25 According to this invention a protuberance is formed on the piston crown, which when the piston is at top dead centre projects into the combustion chamber and has a portion of its wall lying close against a 30 portion of the wall of the combustion chamber. Preferably the protuberance has a portion with a wall parallel to the axis of the piston which wall is parallel to, and, at 35 top dead centre, lies close against, a portion of the wall of the combustion chamber similarly formed parallel to the axis of the piston. One form of this invention is as 40 follows: The cylinder is substantially as described with reference to Figures 1 to 3 inclusive of the Specification No. 287,258. On the crown of the piston is formed an upstanding projection with a flat top nor- 45 mal to the axis of the cylinder and walls parallel to the walls of the combustion chamber into which this protuberance projects, at top dead centre, about one quarter of the depth of the combustion chamber. The walls of this protuberance lie 50 close against the walls of the combustion chamber, so that there is a comparatively small space for the compressed mixture between the piston and the walls of the cylinder, except immediately on top of the 55 said protuberance. I have found that with a cylinder so described and using a suitable fuel, the compression ratio can be raised to a figure in the neighbourhood of 8 to 1 without 60 risk of serious detonation. In another form of this invention a combustion chamber is formed as described in Application for Letters Patent No. 28240 of 1937 (Serial No. 505,895). A pro- 65 tuberance is formed on the piston which projects into the combustion chamber below the inlet valve and has walls parallel to the axis of the piston. The walls of this projection lie close against the walls 70 of the combustion chamber so far as these overlap the cylinder, the walls of the projection at other points conforming to the walls of the cylinder. In this case the projection does not have a flat top, but has a 75 top inclined, the highest point of the projection being furthest from the exhaust valve. The inlet valve is slightly inclined in the opposite direction to that of the top of the protuberance and the top dead centre 80 of the protuberance is at one side approximately two thirds of the way up into the combustion chamber and at the other side one third. In the case of each of the described ex- 85 amples of the invention there is a confined space for the mixture under the portion of the cylinder wall which projects normal to the axis of the cylinder and between the protuberance and the walls of the combus- 90 tion chamber which adjoin such projecting part of the cylinder wall. Dated the 21st day of December, 1938. CLAREMONT HAYNES & CO., Vernon House, Sicilian Avenue, Bloomsbury Square, W.C.1, Applicant’s Solicitors. [Price 1/-] | ||