| 摘要 |
459,917. Powdered - fuel engines; valves. SCHICHAU GES., F., Schichaustrasse, Elbing, Germany. May 20, 1936, No. 14302. Convention date, May 20, 1935. [Classes 7 (ii) and 7 (vi)] In an internal-combustion engine using powdered fuel, the fuel valve and its seating. are adapted for making contact at a line or narrow annular zone, and the valve or the seating has a curved profile at the point of closure. A valve 4, Fig. 1, and its seating 5 controlling admission of fuel from a hopper 1 to a precombustion chamber 2 are both curved at the point of contact D. The members 4, 5 are made of material of a surface hardness of more than 400 Brinell units, preferably nitrided steel or hardened tool steel. The valve 4 is spherical and is operated by a rod 6 having a spherical head 7 fitting within the valve, play being provided by a gap 9 between the rod and a securing-nut 8. The pressure of the valve on its seating is at least three times that in the opening direction, whereby particles of fuel on the line or surface of contact are crushed. In modifications, the valve 4 is conical, or has contacting surfaces of large radius, and may be concave instead of convex. To prevent excess of powder being crushed between the valve and its seat, the flow of fuel to the closure point may be throttled. This preliminary throttle may be a trap for foreign bodies, e.g. it may be of magnetic material so as to trap iron particles ; also, it may form an additional closure-device so as to stop blowing back of the combustion gases into the fuel, at least one of the closure surfaces being curved. Fig. 3 shows a preliminary throttle in the form of a ported sleeve 15 surrounding the valve which in this case is a piston 13. Ports 18 in the sleeve 15 are closed by the piston slightly before the valve engages its seat, this interval being varied by axial adjustment of the sleeve. The ports 18 are triangular or of other shape adapted to provide a rapid increase of the area uncovered consequent on the movement of the valve. During the interval between closing of the ports and seating of the valve, gas under pressure may be blown past D for scavenging, or the precombustion chamber 11 may be exhausted as the valve opens but before the ports are uncovered. The lower edge of the sleeve 15 may have a knife edge and may be guided by the seating D. In a further modification, Fig. 5 (not shown), the preliminary throttle is in the form of a spring ring fixed to the valve and adapted to shut off the supply of fuel before the valve is seated. Part of the weight of the powder in the hopper may be taken and impurities retained by a screen which is placed in the hopper or is movable with the valve. Alternatively, the preliminary throttle may be in the form of a hollow inflated body such as an hydraulic regulator actuated from the engine governor. Fig. 6 shows a valve closing by upward movement and provided with a pear-shaped throttle 28 adapted to protect the valve from the flames of combustion. The valve seat may be cooled by a water jacket 29 or by the injection air, and the part 28 may be heat insulated from the valve by a ring 30 and may be cooled by the injection air also. In a modification, the valve closes by downward movement, and the throttle is a water cooled flange projecting into the space 26, an extension on the valve descending close to the flange.
|
