Patent GB-684905-A (GB)
Title: An improved process for decarbonising internal combustion engines and apparatus for performing such process
Inventor: GRAHAM GEORGE MONTGOMERY
IPC: F02B77/04
Filed: 1951-05-17
Abstract: 684,905. Abrasive blasting. KENT-MOORE ORGANIZATION, Inc. May 17, 1951, No. 11533/51. Class 60. [Also in Group XXVII] A process of decarbonizing an internal combustion engine cylinder head and adjacent surfaces, comprises inserting through an opening into the interior of the combustion chamber a discharge nozzle having a smaller cross-section than said opening, projecting a predetermined quantity of hard combustible granules through the discharge nozzle by a fluid blast while manipulating the discharge nozzle to direct the projected granules against the various interior surfaces of the combustion chamber to dislodge carbon particles therefrom, and conducting the granules and dislodged carbon particles out of the combustion chamber through a return conduit surrounding the discharge nozzle and fitting over said opening by maintaining said blast effective after such time as the predetermined quantity of granules has been projected until the combustion chamber has become substantially exhausted of the dislodged carbon particles and projected granules. Apparatus for performing the process comprises a cylindrical casing 12 to which is secured a smaller casing 14; casing 12 has a removable lid 18 with handle 20. Transport wheels 16 are provided. The casing 12 contains a granule discharge chamber A, an intermediate hopper B and an upper hopper C. The intermediate hopper B is funnel-shaped, having a side wall portion 22 interlocking with the casing 12, and terminates in an outlet 24 telescoped within a pipe 26 communicating with a valve body 28 which in turn communicates with and extends into the granule discharge chamber A; the discharge of granules from hopper B into stand pipe 30 is controlled by plug valve 32 operated by handle 84. An inspection window 86 is provided. The upper hopper C comprises a funnelshaped foraminous element 38, the upper portion being surrounded by a cylindrical shell 40 and the lower portion 42 telescoping into the upper end of a tubular section 44 below the lower end of which is disposed a spreader 46. A flange 50 on the shell 40 seats on a supporting ring 52, a packing ring 54 being provided; the ring 52 rests upon the upper margin of a cylindrical container 56 supported on a packing ring 58 carried by a supporting ring 60 interlocking with the casing 12. The cylindrical container 56 has a screen-like wall 65 over which is extended a filter cloth 66; the container 56 has a bottom portion 62 and a gasket 68. Used blast granules and dislodged carbon particles resulting from the blasting operation are directed into the hopper by tubular element 70 carried by the flexible return line 72 from the blast nozzle assembly. Dust and fine particles pass through the screen-like funnel element 38 and are collected within the cylindrical container 56; the air passes through the filter well of the container and escapes over the top of the container wall underneath the cover 18 which does not form a tight seal with the wall of the casing. The granule discharge receptacle A comprises a chamber 76 with a sloping bottom 78 and a cover 80. An air jet tube 84 projects into the chamber and extends through the stand pipe 30 toward an outlet tube 84. A second jet tube 86 communicates with the interior of the chamber through the sloping bottom. The chamber has an upright passage 88 the upper end of which is obstructed by an adjustable pin 90. An air pipe 92 supplies compressed air to the jets 82, 86, the flow being regulated by a valve 94 operated through stem 96 by handle 100. The valve can be set to permit flow of air to both jets 82, 86 simultaneously (blasting) or to jet 82 only (cleaning) or to cut off air from both jets. A pressure gauge 104 is provided. A relief valve 106 is provided on the discharge conduit 84; the conduit 84 leads to a nozzle assembly. The nozzle assembly comprises a shell 110 terminating in an end fitting 112 e.g. of synthetic rubber, having a bevelled end. The shell has an angular outlet portion 114 with which the return tube 72 is connected. The discharge tube 84 communicates with discharge nozzle 116 coupled to the flexible tube 84 by clamping means 118; a cushion ring 120 is provided. The nozzle 116 has an angular end portion 122 and the clamping means 118 has a similarly directed pointer 124 to indicate to the operator the direction of the end 122. The nozzle 116 extends slidably and rotatably through the shell 110 and through packing washer 126 therein. A spring 128 between the shell 110 and clamp 118 normally holds the nozzle upwardly with respect to the shell 110; it is depressed by pressing on the cushion ring 120. The nozzle 116 is rotatable relative to the shell 110, and is also shiftable axially and tiltable relatively to the shell, so that the granule blast may be directed all around. The apparatus includes a valve position indicator ring 130 which can be seated upon the engine distributer casing 132; a lug 136 on the ring 130 is received in a notch 134 provided in the casing 132 for co-operating with a corresponding lug on the distributer cap. The ring 130 has numerals corresponding to the number of cylinders. The rotor 138 of the distributor rotates within the ring 130 and when the shoe 140 of the rotor engages the contact lug indicated by a numeral, e.g. 8, this indicates that the valve in number 8 cylinder is closed and the piston is in the " proper position," i.e. slightly below the top of the piston stroke. In carrying out the process, the spark plug is removed from the cylinder to be treated and the engine turned over until the piston is in the " proper position " and the valves are closed. The end fitting 112 is placed against the bottom of the spark plug counterbore surrounding the spark plug opening 19. The discharge nozzle 116 is projected through the spark plug opening against the resistance of spring 128 until the angular end portions 122 can be hooked under the edge of the opening. The valve 34 is opened to fill the stand pipe 30 with granules and is then closed. The valve 94 is then operated to admit air to jets 82, 86 so that granules are delivered to the tube 84; used granules and dislodged carbon particles are blown out of the combustion chamber through the end fitting 112, outlet 114 and return tube 72. Valve 94 is then operated to shut off air to jet 86 and jet 82 only is used to scavenge used granules and dislodged carbon from the combustion chamber. Short grain hard rice granules may be employed; any which remain after scavenging will be consumed or blown out through the exhaust when the engine is run. A modified form of apparatus comprises a boxlike casing supported upon a portable stand 150, Fig. 5. A granule chamber assembly is located within portion 152 of the casing; another portion 154, detachably connected to the first portion by connecting means 156, forms a collector box for used granules, the two portions being separated by a screen 158. 84a is a discharge tube, and 72a a return tube. An outlet 160 for dust and broken granules is provided. The stand pipe of the granule chamber is closed by a cap 162 which may be removed to fill the stand pipe with a charge of granules.