GB173544A - Gas engines - Google Patents

Abstract

173,544. Woolf, E. J., and Woolf, J. F. July 5, 1920. Valves.-In a two-stroke engine, a piston valve 25 in a chamber adjacent to the working cylinder controls the passage of fuel mixture through ports 61, 62 to the crank chamber, and the passage of the exhaust from a series ports 50 and the annular passage 52 to the exhaust pipe 28, the fuel mixture passing from the crank chamber to the working cylinder through a series of terminal inlet ports 54. The invention is described as applied to a two-cylinder engine with a single valve chamber between the two cylinders, the pistons having enlarged heads 18 working in the crank chambers, and the rear faces of these heads acting to force air to and fro through the cylinder jackets for cooling. Air heated by the exhaust gases enters the carburettor A at 41, and the fuel-mixture passes through the revensely-curved passage 47 to the valve chamber and thence into the crank chamber. A cold-air inlet 43 formed with the carburettor leads through a chamber 60, in which the valve actuating eccentric works, and through ports 65 controlled by the valve and by the piston head 18 into the crank chambers. The operation of the engine is as follows. On the up-stroke of the piston head 18, cold air for scavenging is drawn into the lower part of the crank chamber through the port 65, and fuel mixture is drawn from the valve chamber through passages 62 into side chambers 56 communicating with the crank chamber. On the down-stroke, the ports 61, 65 are closed, and the mixture and air are compressed without intermixing. The valve 25 places the exhaust passage 52 in communication with the exhaust pipe, and the working pistons then uncover first the exhaust ports 50, and later the inlet ports 54. A stratified charge then enters the cylinder, comprising a charge of air (left in the upper part of the chambers 56 from the preceding cycle), a charge of fuel mixture, and finally a further charge of air. The valve closes the exhaust passages before the piston closes the inlet ports 54.