Patent GB-663165-A (GB)
Title: Improvements relating to the regulation of internal-combustion operated free piston engines
IPC: F02B71/00
Filed: 1948-02-25
Abstract: 663,165. Internal-combustion operated free-piston engines and gas generators. BALDWIN-LIMA-HAMILTON CORPORATION. Feb. 25, 1948 [Oct. 9, 1944 ; June 14, 1945], Nos. 5581/48 and 5582/48. Classes 7(i) and 7(ii) [Also in Group XXIX] An internal-combustion operated. freepiston engine or gas generator has a normally closed direct bounce chamber and a normally closed reverse bounce chamber, manually controlled means to vary the quantity of gas in the reverse bounce chamber and automatic control means to correspondingly vary the quantity of gas in the direct bounce chamber. In the generator shown, Fig. 2, the pressure in an accumulator cylinder 5 is varied by means of a governor A which either supplies high pressure air to it from a supply line 50 or allows air to leak away from it through an outlet 52. The pressure in an accumulator cylinder 4b acting in opposition to the accumulator 5, is controlled by a governor B which either supplies air to it from a line 71 or allows air to leak away from it through an outlet 74. The governor B maintains the pressure in the cylinder 4b constant at whatever value is selected by a hand control 90 operating upon a valve 85. If the pressure varies from the selected value it operates in a bellows 92, Fig. 4, and shifts the valve 85 against a spring or allows the spring to move the valve and the valve either opens a port 81 or a port 82 to a source of pressure connected at 83. If the port 81 is uncovered a valve 75 is opened to permit air from the line 71 to pass into a line 73 leading to the cylinder 4b. If the valve 76 is opened, the air is allowed to leak away through the outlet 74. An enlarged view of the governor A is shown in Fig. 3. A valve 61 is controlled by a lever 24 which is acted on by four bellows 25-28 and a spring 30. The bellows 25 is connected to a compressor cylinder 4a through a pipe 34 and passage 37, non-return valve 35 and adjustable restrictions 36, 38. The passage 37 and restriction 38 are in parallel with the valve 35 and restriction 36. The bellows 26 is connected by passages including an adjustable restriction 43 and non-return valve 41 and pipe. 40 to an equalizing conduit 39 connected to the cylinder 4b. The bellows 27 and 28 respectively are connected to a pipe 44 leading to a conduit 10 connected to the cylinder 5 and a pipe 66 leading to a scavenging air receiver 11. When the pressures in the various spaces of the generator are in a certain desired relationship to one another, the lever 24 is in an equilibrium position. If one of the pressures should change the lever is moved, and the valve '61 moves from its neutral position and admits pressure to one or other of bellows 56, 57 opening one or other of valves 51. 53. If the valve 51 is opened. pressure from the line 50 is supplied to the accumulator cylinder 5 through the pipe 44 while if the valve 53 is opened the pressure can leak away from the cylinder 5 through the pipe 54 and outlet 52. A non-return valve 46 and adjustable restriction 48 are included in the pipe 44. Due to the restriction 36, the pressure in the bellows 25 is dependent on the length of time during which discharging pressure in the compressor continues, The pressure in the bellows 26 and 27 respectively is maintained by their associated restrictions and non-return valves substantially at the maximum pressure in the cylinders 4b and 5 respectively. The pressure in the accumulator cylinder 4b is varied by the hand control 90, and the governor A then adjusts the pressure in the cylinder 5 accordingly. Below the minimum pressure in the cylinder 4b the generator is controlled by a fuel control 104. Reduction of the fuel supplied at each stroke disturbs the relationship of the pressures acting in the bellows 25-28, but the governor A compensates for this. In order that the generator may idle properly, a valve (not shown) is provided between an exhaust outlet 13 and a turbine which can be closed and another valve can be opened to allow the generator to exhaust to atmosphere. This reduces the pressure in the scavenging receiver and the pressure against which the compressor discharges. At this stage, the correct relationship between the various spaces in the generator is still maintained by the governor A. The supply line 50 may be connected to the scavenging air receiver 11 instead of to an independent source of air pressure. This is preferable to taking the supply pressure from any of the other spaces of the generator since the compression ratio can be 7 to 1 when using the scavenging receiver pressure as compared to 10 to 1 when using pressure from the other spaces. The generator is symmetrical about the centre of the combustion chamber and the accumulator cylinder 5 at one end is connected to a corresponding cylinder at the other end by the conduit 10. The conduit 10 may be provided with an extension (not shown), leading to an air pressure storage flask through a non-return pressure regulator valve.  The Specification as open to inspection under Sect. 91 states that the governors A and B are usable separately. This subjectmatter does not appear in the Specification as accepted.