GB461694A - Improvements in or relating to the cylinder heads of internal combustion engines and a method of igniting explosive charges therein - Google Patents

Abstract

461,694. Sparking-plugs. STEVENS, A. H. (Economy Engineering Corporation) May 13, 1935, No. 14022. [Classes 7 (ii) and 7 (iv)] The charge, compressed in the main combustion chamber of an engine cylinder having a compression ratio of more than 3À75 to 1, is ignited by flame from an auxiliary chamber 11, in which the sparking-plug 15 is located, the chamber 11 having a capacity between 0À0012 and 0À006 of the total cylinder capacity, and being formed so that its wall-temperature is maintained at a temperature slightly below the self-ignition temperature of the charge. This wall-temperature, which is preferably not less than 500 to 600‹ F., may be maintained by a thermally or manually operated device or by careful design. The chamber 11 may be formed in the cylinder head casting or in a separate fitting 10 made of bronze or copper ; it may be cubical, spherical or cylindrical in shape, dimensions for specific engines being given ; it, preferably, has one or more Venturi mouths 17 which may be inclined as shown in Fig. 2. A thermal control is shown in Fig. 5 in which a separate fitting 10, comprising the chamber 11, is insulated by an asbestos packing 22. Cooling fins 14 are surrounded by a pair of cylindrical casings 26, 27, fixed and mounted on ball bearings 23 respectively ; these casings have hit-and-miss ports, and are controlled by a thermal device extending through the space round the fins 14, so as to be affected, more or less, by a stream of air from the radiator or other fan. In Fig. 9, the temperature of insulated auxiliary chambers in a four-cylinder engine is regulated by placing a casing 30 over the sparking-plugs ; a thermally-controlled valve 36 regulates the supply of cooling air, exit ports 38 being provided over each sparking- plug. Specifications 141,877 and 216,391, [both in Class 7 (iv)], are referred to.