GB895869A - Improvements in hot-gas reciprocating engines - Google Patents

Abstract

895,869. Hot gas engines. PHILIPS GLOEILAMPENFABRIEKEN N.V. May 6, 1959 [May 10, 1958], No. 7868/59. Class 7(1). [Also in Group XXDC] In a hot-gas reciprocating engine in which the supply of fuel to the heater is controlled by a thermostat and the air supply to the burners by an hydraulically-controlled servomotor, the thermostat 7 which is located in the combustion space 3 adjacent the heating coil 2 acts on a control mechanism 8 to control the supply of liquid fuel to the burner 4 in accordance with engine load. On, e.g., an increase in this load, the temperature on the walls of the coil falls so that the thermostat adjusts the mechanism 8 to supply more fuel to the burners and at the same time decrease the pressure on the downstream side of a flowrestrictor 24 in a fuel supply line 23. The pressure on the upstream side of the restrictor being maintained constant by a pressure-relief valve 56 on the discharge side of a gear-wheel pump 22. This differential pressure causes a piston 30 slidable in a cylinder 29 connected by pipes 27, 28 to opposite sides of the restrictor to move rightwardly to move a piston valve 32 to the right so that pressure liquid, as shown liquid fuel delivered through a branch 37 from the fuel line 23, is directed to act on the underside of a piston 43 which moves upwardly and through a rack and pinion 45, 46 increases the amount of opening of a valve 12 in a line 11 supplying the burner with combustion air so that the increased fuel supply to the burner is matched by a corresponding increased air supply. The air line 11 upstream of the valve 12 is also fitted with a flow-restrictor comprising a Venturi 47 connected by lines 48, 52 to opposite sides of a diaphragm 50 operatively connected by a rod 53 with the piston valve 32. The increased opening of the valve 12 results in leftward movement of the diaphragm 50 and the restoration of the piston valve 32 to its initial position with the piston 43 and valve 12 retained in their new positions until the demand on the engine again changes. The flow restrictors 24, 47 are designed so that their characteristic curves, i.e. volume of flow per unit of time plotted against pressure difference are parabolic with their peaks at the origin of the axes so that the ratio of the amounts of air and fuel flowing through the lines 11 and 23 remains substantially constant.