GB1383815A - Hot-gas engine - Google Patents

Abstract

1383815 Hot gas engines; controlling airfuel ratio PHILIPS' GLOEILAMPENFABRIEKEN NV 1 March 1972 [4 March 1971] 9485/72 Headings F1C and F1S [Also in Division F2] A hot gas engine comprises a heater 10 heated by a burner 14 having an inlet 16 for combustion air supplied by blower 21 and a fuel inlet 15 to which fuel is supplied by pump 20 via fuel supply duct 24, the blower 21 whose output is directly proportional to its speed and the pump 20, whose output is proportional to its speed above a given speed being coupled and having their speeds controlled by a heater temperature responsive device 18. A pressure control valve 27 maintains in operation a substantially constant pressure at the pump outlet and fuel is only permitted to flow from the pump to the burner when this pressure has been reached. A fuel return duct 25 with a restriction 29, is provided. Fuel may be supplied by a viscosity metering pump, Fig. 3, in which fuel passes through inlets 60, 61 to ducts 48', 49', which communicate with pumping grooves 43, 44 along which fuel passes, due to rotation of the pump rotor, to grooves 50, 51 and thence to duct 45 and outlet 53. The grooves may be formed instead in the cylinder 52. The pump may be used for liquid or gaseous fuel. The presence of valve 27 ensures that a higher pressure is imposed on the outlet of the pump than in the absence of the valve causing a "virtual leakage" of fuel reducing the pump's output. The valve shown in Fig. 4 has a relatively large area of diaphragm 74 subject to pressure in inlet chamber 71 and a relatively small area subject to pressure in the outlet chamber 72 so that variation of pressure in the latter has little influence on the pressure in the inlet chamber.