Although best known for its line of high-quality horizontal singles, Weber Gas Engine Co., Kansas City, Missouri, got its start with a unique and somewhat complex inverted vertical engine. Designed by company founder George Weber, the engine, which apparently went into production about 1890, was awarded patent no. 444,031 in 1891.
Perhaps hoping to skirt any infringement of Otto’s patents, which included half-time cam gear valve actuation, Weber concocted a novel valve actuation system that used a double screw on the crankshaft to toggle a rocker arm to affect valve opening and closing.
Visible in Fig. II of the patent drawings, the double screw featured two grooves that converged to a single point, from which they then diverged halfway around the screw, then back again. As the crankshaft spun, the rocker arm, which was keyed to the screw drive, would move back and forth. As it did so, pawls on the end of the arm would alternately act upon the requisite linkage to actuate the intake and exhaust valves.
The mechanically actuated valves were quite interesting. The exhaust was the familiar poppet valve, but the intake was a wedge-shaped slide valve that opened or closed transfer ports in a fuel/air chamber, blocking or allowing the charge to pass to the cylinder. In its closed position, the slide valve’s flat face covered the transfer ports, its ramped backside wedged against a similarly shaped fixed lug, causing it to be pushed against the transfer ports for a secure seal.
A separate valve controlled the admission of fuel to a burner-fired hot tube. As the intake slide valve shut off the fuel/air charge fed into the cylinder, linkage controlled by the aforementioned rocker arm actuated a separate, horizontally positioned rotary valve intersecting a secondary fuel/air chamber leading to the cylinder. As the spring-loaded valve turned, it uncovered a port in the side of the chamber leading to the hot tube. Compressed gas in the cylinder was thereby allowed to shoot through a matching opening in the valve face into the hot tube where it was ignited, thus igniting the main charge in the cylinder. The spent charge was then expelled through the exhaust poppet valve. Intriguingly, the actuating rod for the exhaust valve was cushioned upon closing under spring pressure by a dashpot.
The rod that latched and unlatched the linkage for opening and closing the rotary valve was attached to the rocker arm. Mounted on an eccentric on the rocker arm, the rod could be adjusted to make the rotary valve open earlier or later to affect ignition timing. The rotary valve had a spring to aid opening, and was closed by one of the pawls on the end of the rocker arm, which lifted the rod as the rocker arm pivoted inward.
The engine included two auxiliary valves, one for the intake and the other for the exhaust, both closed by gravity. The auxiliary intake valve apparently lifted open as the piston drew in a fresh charge and pulled the fuel/air mixture into the chamber housing the rotary valve. The auxiliary exhaust valve apparently opened under pressure as the spent charge was pushed out of the cylinder, the exhaust passing through a chamber evacuated by the opening of the poppet exhaust valve. The vertical auxiliary valves had short stems running in guides in the valves — the auxiliary intake stem fit into the auxiliary exhaust, the auxiliary exhaust into the exhaust poppet valve — along with additional guides at their lower periphery to ensure proper seating.
Certainly a unique design, it’s unclear how many engines of this type were actually manufactured. If any were produced, there couldn’t have been many as there are no known survivors. According to C.H. Wendel’s American Gasoline Engines Since 1872, by 1893, just two years after this patent, Weber had apparently abandoned this design and was producing a more conventional horizontal engine, setting the pattern for the company for years to come. Interestingly, in the late 1890s Weber introduced a new and more conventional 2hp vertical engine, with the crankshaft at bottom and the cylinder at top, and with more conventional valve operation, but still using hot tube ignition. Wendel notes that Weber abandoned the model a few years later, around 1902.
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