GB568002A - Improvements in or relating to valve gears, particularly applicable to internal-combustion engines - Google Patents

Abstract

568,002. Valve gear; supercharging. WELLS, R. G. Sept. 7, 1943, No. 14611. [Classes 7 (ii) and 7 (vi)] In a two-stroke engine having inlet ports controlled by the power piston and exhaust ports in an extension of the cylinder head and controlled by an auxiliary piston, two arms extending from the same side of a rocking shaft are connected respectively to the auxiliary piston by a pivoted link and to a coupling rod actuated by an eccentric or an auxiliary pin on the engine crank-shaft, and the coupling rod is under tension during the working stroke of the engine. The crank-shaft 14 carries an eccentric 15 of which the strap 16 rocks a third order lever 18 having its free end 20 pivoted to a rod 21 which couples the lever to an arm 22 of a rock-shaft 23. A second arm 24 on the rock-shaft is linked at 26 to a piston valve 28 slidable in an extension 29 of the cylinder 11 to control exhaust ports 30. The pivotal couplings may be made adjustable. The arms 22, 24 and the lever 18 and their connections are so proportioned that a large part of the piston travel is occupied in covering or uncovering the ports 30. In a modification, the connection 20 comprises a pin and slot, the position of the pin in the slot being determined by an adjustable radius rod. As shown, the valve 28 supports a piston 35 provided with automatic or other valves 37 through which, on the instroke of the valve 28, air passes from an inlet 40 to the interior of a cylinder 36 housing the piston, the air being compressed on the outstroke and delivered past valves 38 through a passage 39 to the inlet ports 42 of the cylinder. When the piston 12 is at top dead-centre, the link 26 is substantially vertical and on ignition of the charge, the pressure on the valve 28 puts the rod 21 under tension.