The desire to innovate was a constant in early gas engine design, a fact amply illustrated by John W. Burkett’s 1918 patent for a combined poppet/sleeve valve mechanism for a 4-cycle engine.
An engineer with the Kansas City Hay Press Co., Kansas City, Mo., in the early 1900s, Burkett established Burkett Mfg. Co., Columbus, Ohio, about 1913, manufacturing gas-powered hay presses. Intriguingly, while production Burkett 4 HP and 6 HP engines were of conventional design, with a simple atmospheric intake valve and mechanically operated exhaust valve, his patent — no. 1,253,933 — is for a comparitively complicated valve mechanism pairing a single poppet valve with a sleeve valve actuated by what was effectively a rack and pinion.
In Burkett’s design, a cast iron tube or “cage” was fixed in the center of the cylinder head, inline with the cylinder. A single horizontal poppet valve passed through the cage, supported at both ends. The cast iron cage was also the seat for the poppet valve, its valve head facing the combustion chamber. The cage had ports at 6 and 12 o’clock for intake and exhaust, respectively. Surrounding the fixed cage was a rotating sleeve, with corresponding ports for intake and exhaust. The single poppet valve was held shut by spring tension and compression, opening atmospherically during the intake stroke but mechanically actuated during the exhaust stroke.
A link rod from the crankshaft operating on a gear or eccentric pushed and pulled a bell crank running across the top of the cylinder head, with a finger on the bell crank working the poppet valve during exhaust. A gear on the bell crank meshed with a geared plate mounted flat to the outside face of the cylinder head. The plate was directly attached to the sleeve valve. As the gear meshed with the plate, the plate and thus the sleeve valve rotated back and forth, alternately uncovering the intake or the exhaust port, with both covered during compression and ignition. In this way the single poppet valve controlled admission or exhaust at the cylinder proper, with the sleeve valve controlling admission of fuel/air to the poppet and exhaust of spent gases from the poppet.
According to Burkett’s patent, the design ensured more efficient vaporization of the incoming fuel/air charge by exposing the incoming charge to the heated sleeve valve. Whether Burkett ever marketed any engines with his poppet/sleeve valve design is unknown, but his patent stands as a reminder of the never-ending quest for innovation.
Know of an interesting patent? Contact Gas Engine Magazine at 1503 S.W. 42nd St., Topeka, KS 66609-1265 or email rbackus@ogdenpubs.com.
