Patent GB-262831-A (GB)
Title: An improved two-stroke internal combustion engine
IPC: F01K1/02
Filed: 1926-02-17
Abstract: 262,831. Martinka, M. Nov. 11, 1925, [Convention date]. Two-stroke-cycle engines; cylinders, regenerative bodies in and varying clearance of.-In an engine having heat regenerators in the power cylinder and wherein a cold working charge is supplied by a separate pump at the highest pressure of the working cycle, expansion chambers are connected to the cold side of the regenerators the volume of the chambers being varied during the expansion and compression periods of the power cycle so as to compensate for the variation in volume of the gases contained in the regenerators during these periods; as a consequence the gases in the power cylinder are in effect isolated during these periods from the regenerators and the chambers beyond them on the cold side. As shown in Fig. 2 the engine works on a super atmospheric cycle, the power cylinder 1 exhausting through the main regenerator 5 into a receiver 9 at a pressures p'; the gases from this receiver are delivered to a second receiver 6 by a pump 11 at a pressure p<2>, which is the highest pressure in the working cycle. During each exhaust period a portion of the gases are withdrawn from the system through auxiliary regenerators 22, 23 by measuring pumps 35, 36, which deliver the gases at the pressure p<1> to a receiver 27; these gases further expand ta atmospheric pressure in a motor 28 used to assist the main piston 4 in driving pumps 12 and 13. These pumps compress air and gaseous fuel to the pressure p<1>, the heat of compression being abstracted by the gases flowing to the motor 28. The air and gas are raised to the pressure p<2> by pumps 16 and 17. The mass of the gases abstracted by the pumps 35, 36 is equal to the mass of the new charge delivered by the pumps 16, 17. An expansion chamber 29 is connected to the power cylinder 1 on the cold side of the regenerator, and two auxiliary expansion chambers 30, 31 with pistons 33, 34 are connected through valves to the cold side of the auxiliary regenerators. The main and auxiliary expansion pistons 32, 33, 34 are driven so as to lag behind the power piston 4; valves are arranged in the pipes connecting the receivers and pumps to the cylinder. Owing to the timing of these valves and the effect due to the lagging of the pistons, the following cycle is obtained in the power chamber and regenerators :-Assuming the receiver 6 to be fully charged, the inlet valve 7 is opened and combustion products from the previous cycle enter the chamber 29 and pass through the regenerator 5 into the power cylinder 1; towards the end of this admission a new charge is delivered at the maximum pressure of the cycle by the pumps 16, 17 through the auxiliary regenerators 22, 23 into the power cylinder, this charge burning as it enters and raising the temperature of the gases in this cylinder. The expansion period follows in the power cylinder and during this period all the expansion pistons move outwards to accommodate the increase in volume of the gases in the regenerators due to the rise in temperature. The exhaust now follows from the power cylinder, the gases passing out through the main and auxiliary regenerators, the pressure in the power cylinder being p', the lowest of the cycle. During the compression period of the power piston, the expansion pistons move in. wards to raise the pressure of the gases in the regenerators to the pressure p<2>. By these means the gases in the power cylinder do not affect the gases in the regenerators during the expansion and compression periods; while the gases are being admitted from the receiver 6 and during the exhaust to the receiver 9 the expansion cham. bers have no effect on the gases due to the working of the associated valves. The gases drawn into the auxiliary expansion chambers 30, 31 are compressed into the receiver 39 at a pressure slightly above the pressure p<2>, these gases being used to force the new charge into the power cylinder. Instead of a single expansion piston 32, two pistons may be used their effect being successive. The chambers 27 and 9 may be connected. The expansion chamber 29 and its piston may be replaced bv a number of receivers 48<a>-f, Fig. 9, in which are stored gases at pressures graded from p<1> to p<2>. The receivers are connected to the cold side 46 of the main regenerator 5 through valved pipes, the valves .opening in sequence so that only one of the receivers is connected to the chamber 46 at a time. During the expansion period of the power piston the receivers are connected in the order of descending pressures the reverse order taking place during the compression period.