Vertical crankshaft engine having longitudinally opposed cylinders

Abstract

A riding tractor with an elongated longitudinal frame is provided with a vertical crankshaft internal combustion engine having opposed pistons aligned in the longitudinal vertical plane of the tractor. In operation of the engine a dynamic force couple is created by the vertical spacing of the cylinders which induces vibrations tending to pivot the engine about its base, which is secured to the frame of the tractor. The frame has a relatively large moment of inertia about its wheeled support which effectively resists the rocking movement of the engine in the longitudinal plane of the tractor. The engine crankshaft includes an output shaft portion extending downwardly from the engine to which V-belt pulleys are connected for driving the drive wheels of the tractor and an underslung rotary mower by appropriate V-belts. In one version of the engine each cylinder has its own carburetor, intake manifold, exhaust manifold and muffler. In a second version of the engine, the air intake manifold and ports are located at one lateral side of the engine and the exhaust ports and manifold are located at the other lateral side of the engine. This provides maximum isolation of the carburetor from the hot exhaust system. In a third version of the engine both air intake and exhaust manifolding and ports are located on one lateral side of the engine. In the second version of the engine the intake manifold and carburetor are disposed below the exhaust manifold and muffler so that the heat rising from the exhaust manifold and muffler will not pass over the carburetor.