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 cylinders of internal combustion engines, specifically a two-part cylinder liner.
| Identifier | ExFiles\Box 140\4\ scan0272 | |
| Date | 6th November 1924 | |
| Half length cylinder liner. LEYLAND MOTORS LIMITED. PATENT SPECIFICATION 224,539 Convention Date (Italy) : Nov. 6, 1923. Application Date (in United Kingdom) : Nov. 6, 1924. No. 26,531/24 Complete Accepted : June 11, 1925. COMPLETE SPECIFICATION. Improvements relating to the Cylinders of Internal Combustion Engines. We, FIAT, SOCIETA ANONIMA, a company existing under the laws of Italy, of 250, Via Nizza, Turin, Italy, do hereby declare the nature of this invention and 5 in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement:— It is known that the liners of the cylin- 10 ders of internal combustion engines are subjected to considerable stresses due to pressure and temperature, and to the wear and tear caused by the piston rings. These stresses and the wear and tear 15 resulting from the action of the piston rings are, however, practically confined to the end of the liner in the zone of the combustion space or chamber. The stresses due to pressure and temperature 20 decrease rapidly as soon as the piston passes the upper dead centre, likewise the wear and tear resulting from the friction between the piston rings and the cylinder liner. 25 This is proved by the fact that the friction is caused largely by the pressure of the gases which act behind the piston rings and keep them pressed against the cylinder, and by the fact that at the 30 upper part of the cylinder in the zone of combustion, where the pressure between the liner and the piston rings is highest, the lubricating oil arrives in a minimum quantity and then its efficacy is reduced 35 because the superficial temperature of said zone is considerably raised. Two part liners for the cylinders of internal combustion engines have been proposed in which the upper part is of 40 more resistant metal than the lower part and in which said lower part is so long that the piston rings continuously remain within it while the upper part surrounds the combustion chamber. 45 In accordance with this invention and with the object of eliminating the inconveniences above mentioned, the cylinder liner is divided into two parts adjacent the zone of combustion but at a distance 50 from the upper dead centre at which the combined action of the friction of the piston rings and of the pressure and temperatures of the combustion gases ceases or becomes negligible, that is to say the 55 joint is so placed that the upper piston rings pass over the same. Said upper part of the liner may be constructed of materials which are highly resistant to mechanical and thermal 60 stresses and to wear and tear, thereby permitting the wall thickness to be reduced so as to ensure a more active cooling. It will be apparent that the arrange- 65 ment prolongs the life of the liner and reduces wear and tear to a minimum when resistant materials are used for the upper part. Further, by the separation of the upper part (which as previously 70 shown is the part subjected to wear and tear) from the lower part (the life of which is practically unlimited) only the upper part need be renewed, thus reducing the cost of maintenance of the engine. 75 By way of example, one form of cylinder embodying the invention is shown in section on the accompanying drawing. In the drawing, 1 denotes the cylinder jacket in which is arranged the liner com- 80 prising a lower part 2 of customary material and an upper part 3 of highly resistant material. The two parts 2 and 3 of the liner are shown connected with each other by means of flanges 4 and con- 85 necting bolts 5. When the part 3 is impaired it is removed and replaced by a new one, while the lower part continues to be used. Having now particularly described and 90 ascertained the nature of our said inven- [Price 1/-] | ||