Patent GB-155314-A (GB)
Title: A new or improved combined internal combustion and compressed air engine
IPC: F02G3/02
Filed: 1919-06-17
Abstract: 155,314. Robinson, R. W. June 17, 1919. Starting and stopping pumps automatically. - An internalcombustion engine drives a compressor supplying air to a reservoir from which an air engine is driven, the piston of the compressor through a rocking shaft and levers giving a mechanical advantage to the engine during the latter part of its stroke, the supply of air to the air engine from the reservoir being automatically throttled as the reservoir pressure falls, and the combustion engine being started and stopped in accordance with the fall or rise of the reservoir pressure. The stroke of the combustion engine is always of the same speed and power. The piston a', Fig. 1, of the combustion cylinder a is connected to the crank-lever a<2> on the rocking- shaft d, the piston b<1> of the air compressor being similarly connected to the same shaft. The compressed air reservoir c surrounds the compressor cylinder, with which it communicates through a valve b<4>. Air is led from the reservoir through a pipe f to a carburettor l and thence to a valved port k in the combustion cylinder; the pipe f is also in communication through a small pipe j<1> with the top of the fuel tank j. The carburetted air entering at the port k drives the piston through a part of its stroke. The port is then closed and the charge ignited, completing the stroke. A smaller air reservoir c', Fig. 2, is connected with the reservoir c through a reducing valve v, and surrounds a cylinder e communicating with it through ports e', in which is a piston e<1> connected to a crank on the rocking-shaft, and arranged so that the piston effects the return stroke of the engine and compressor. The ports c<3> are closed by the piston before the end of the stroke, providing an air cushion. In small engines, an adjustable coiled spring on the rocking shaft may replace the cylinder e and piston e<1>; in this case, the bore of the cylinder a may be cut down at the ends to form air cushions as the cylinder c is cut down in the construction shown. and a one-way valve may be provided in the end of the piston or cylinder to give a quick start on the return stroke. A second reservoir c<2> fed through a reducing valve from the main reservoir supplies air through a pipe f<2> to actuate the admission and exhaust and ignition mechanism. The pipe f<2> leads to a port u<5>, Fig. 4, in a cylinder containing a grooved piston valve subject at one end to the reservoir pressure entering bv a pipe f<3> leading from the pipe f, and at the other end to the pressure of an adjustable spring u<2>. Normally the groove u<4> in the piston valve allows air to pass to valve chamber g<4> and cylinder g, but the air is cut off by the valve when the reservoir pressure rises. The cylinder g contains a piston g<1> connected by a rod to a piston h<1> in the cylinder h. The connecting-rod actuates a lever j<2>, to which a piston valve j, j<1> is pivotally attached, the valve moving in a cylinder provided with a port k forming a common inlet and exhaust port for the combustion cylinder and a port m communicating with the carburettor. The port k is alternately placed in and out of communication with the port m by the motion of the pistons so that a charge of carburretted air is admitted to the combustion cylinder at intervals. The inner end of the cylinder h is connected with the pipe f<2> through a one-way valve at the end and through a port near the end, allowing a quick start to the stroke and also a cushioning effect. When the pressure falls below normal, air is admitted past the groove u<4> to the cylinder g, immediately driving the pistons g<1>, h<1>, j, j<1> through their full strokes and allowing a charge to pass into the combustion cylinder. The shaft d, Fig. 2, is consequently rocked and communicates motion to a lever i<3> and a valve-rocking shaft i, Fig. 4, cams o - -o<3> on which acting on adjustable levers s actuate the valve p<2> to close the admission port of the cylinder g and an exhaust valve g<2> when a correct charge has been admitted to the engine cylinder. The air cushion formed in the cylinder g after the piston has passed the exhaust port brings the piston valve to rest at a point where the piston j covers the port k, and a stud j<3> on the lever j<2> trips a pawl q closing the ignition circuit near the end of the engine stroke. The cam o<1> opens a second exhaust port g<3> of the cylinder g allowing the piston valve to complete its stroke and open the exhaust port k, whereupon the engine and compressor pistons a<1>, b<1> are returned by the piston e<1>, and at the end of this stroke the valve p<2> opens the end of the cylinder g<2>. The cam o<3> is set so as to break the ignition circuit immediately after making. A passage z throttled by a screw valve connects the ports g<2>, g<3>, allowing the air to exhaust in case of a misfire. The air from the main reservoir c, Fig. 2, is led through a pipe f<1> to the jacket of the combustion cylinder, which is provided with perforated ribs a<3> giving a helical passage to the air, and afterwards passes by a pipe n surrounded by the exhaust pipe n<1> to the air motor cylinders which are heated by the exhaust gases. The end of the pipe f extending within the reservoir c 's closed, air entering by transverse slots in the sides and by similar slots in a cylinder w sliding on it and connected to a piston w<1> which moves in a cylinder communicating with the main reservoir through a valve w<3> and having a relief cock w<4>; by this means, when the air engine is run at too high a speed, the consequent reduction in the reservoir pressure moves the piston w<1> and cylinder w forward, throttling the air supply. A spring may be substituted for this piston and cylinder device. In a modification, the pistons g', h<1> are dispensed with, a piston j' moving in the cylinder g. In both constructions, the piston j is formed with an annular depression which is opposite the port k when the charge is fired, so that this heated portion does not come into contact with the cylinder wall. A reserve reservoir may be provided which is disconnected from the main reservoir when the engine is not in use. A two-cylinder air motor may be used, exhausting at low pressure, or a turbine motor. The engine and compressor may supply a reservoir at constant pressure for any purpose.