GB690805A - Improvements relating to piston engines operated by catalytic oxidation of fuel - Google Patents

Abstract

690,805. Generating combustion products under pressure. HOUDRY, E. J. March 17, 1949, No. 7337/49. Class 51(i) [Also in Group XXVII] Generation of combustion products under pressure in a manner similar to that disclosed in Specifieation 690,804 is employed in combustion product engines (see also Group XXVII). The products of catalytic oxidation are utilized to drive a piston of an engine and a part of the catalytically oxidized fuel is exhausted at about the end of the expansion stroke of the piston the remainder being compressed by the piston on its compression stroke and returned to a chamber containing the catalyst while at the same time fresh oxidizable fuel and fresh oxygen containing gas is mixed with the returned oxidized fuel. Fig. 1 shows an engine comprising a cylinder a in which operates a piston b and a catalyst chamber e to which air and fuel are supplied and from which products are passed into the cylinder to operate the piston. With the piston at the top of its compression stroke as shown a valve o is opened and products from the chamber e pass into the cylinder. The valve remains open until the piston reaches a position approximately indicated by the dotted lines x. The products in the cylinder then expand and drive the piston down until it uncovers an inlet port c and an exhaust port d. The exhaust is throttled at d<SP>1</SP> so that not all of the exhaust gases will escape. When the piston starts its upwards course the cylinder contains the equivalent of 690 cc. of products calculated at atmospheric temperature and a pressure slightly above atmospheric and 310 cc. of air at the same pressure. During the compression stroke air and products enter the catalyst chamber through a pipe f containing a non-ceturn valve f<SP>1</SP>. During the whole of the cycle fuel is being pumped into the catalyst chamber the fuel pump being indicated at p. The fuel pipe h may connect directly with the catalyst chamber. The .engine may comprise a plurality of cylinders and corresponding catalyst chambers. In Fig. 6 fuel is introduced into a catalyst chamber at 84. Air or other oxygen bearing gas may be admitted direct to the chamber but it is preferably admitted through an inlet port 85 in the cylinder and thence through a pipe 94 with a non-return valve 95. A valve 92 by which products are admitted to the cylinder is open during only a minor part of the expansion stroke until the piston reaches a position more or less approximating to that indicated by the dotted line 99. Partial exhaust of the products takes place. Fresh fuel and air either or both may be admitted continuously or intermittently by pumps. The catalyst chamber comprises a cylinder 102 of porcelain enclosed in a casing 101 of stainless steel. In the cylinder 102 are packed a series of catalyst supports 103 which may be of hard alumina each support being provided with a series of parallel slots. The supports are so positioned that the slots of one disc extend at right angles to the slots of adjacent discs forming tiny interstices which are packed or impregnated with catalytic material as for example copper chromium or platinum. Other materials mentioned as suitable for the catalyst are vanadium. manganese, molybdenum, silver, nickel, cobalt, iron, magnesium, tungsten, thorium, lead and zinc. Mixtures of certain elements are mentioned. Copper manganese finely divided over an activated alumina support effects oxidization at below 300‹C. A closure 105 of porcelain is provided for the cylinder 102. The supports may be activated zirconia or silica gel. Oxygen may be used in place of the air. Various operating temperatures and pressures are quoted. The maximum temperature should be not less than about 600‹C the permissible upper limit being in the neighbourhood of 1100‹C and a temperature in between is preferred for example 850‹C. The fuel used may be hydrocarbon fuel such as gas, gasoline, kerosene or heavier fuel oil.