Patent GB-774013-A (GB)
Title: Improvements in liquid fuel evaporators
IPC: F02M31/18
Filed: 1954-10-29
Abstract: 774,013. Fuel evaporators; cycles; valves. BOK, H. F. and BOK, E. Oct. 29, 1954 [Oct. 29, 1953 ; May 12, 1954], No. 31337/54. Classes 7 (2), 7 (3) and 7 (6). A liquid fuel vaporizer more especially for fuel injection internal combustion engines in which a charge of fuel gases at high pressure and temperature is injected into the compressed air in the cylinder at the end of the compression stroke after which the mixture is ignited is characterized by an evaporation chamber provided with an inlet for the liquid fuel and an outlet connected to the gas conduit to a gas consumption device in which chamber an electric resistor with a large surface in direct contact with the liquid fuel in the chamber is placed which resistor is at least partially immersed in the liquid fuel in the chamber whereby the vapour formed is pressurized and forced to the gas consumption device by its own pressure. The invention is applicable to engines in which ignition is caused either by a spark or by the temperature of the compressed air in the cylinder. In Fig. 1 fuel under pressure enters at 6 a vaporizer comprising a casing 1 preferably of steel and the gases produced are led to the cylinder or cylinders through a conduit 4. In the vaporizer a ceramic mantle 9 is arranged and within this is a double walled electric resistance element 12, 12a. A heat insulating layer 15 restricts heat radiation. The working temperature can be 500-800‹C. Adjustment of the temperature can be obtained by regulating the current through the resistor. The resistor could be formed as a spiral centrally placed in the mantle 9. In Fig. 2 a main pump 23 is supplied by a pump 22 and feeds vaporizers 29. From each vaporizer 29 a gas conduit leads to a valve 30 regulating the inlet of gases to the combustion space of the cylinder. The inlet valves for gaseous fuel may be directly driven from a shaft coupled to the motor shaft. Coarse and fine filters 27, 28 are provided. A single vaporizer can serve for several cylinders or even all cylinders. A six cylinder engine could be provided with two or three vaporizers. It is necessary that the injection pressure of the fuel should increase with speed. Starting from a rather low speed by adjusting the voltage of the resistor 12, 12a the electric energy is regulated so that the quantity of gases generated is appropriate. The lift of the valve is regulated when the engine speed increases the energy supplied to the resistor 12, 12a is increased. Adjustment of the pressure of the pump and of the voltage of the resistor in proportion to speed can be automatically effected. In Fig. 3 a two stroke engine is provided with vaporizer 29. The valve 36 which controls the supply of gases to the cylinder may be spring loaded and is operated by a projection 40 on the engine piston 31. In the supply conduit to the valve chamber a back pressure valve may be arranged. The fuel used may be gasoline or other hydrocarbon. It is possible to use diesel fuel and other heavier oils. It is stated that passage section for the gases in the valve may be ten times as large as that of the usual valves. The injection pressure may be in the order of 100 atmospheres. At starting precombustion may occur in the space 35.