Abstract: The performance and durability of compressor wheels coupled to turbocharger shafts are at odds with each other in that a higher rotational speed can be accommodated by an aluminum compressor wheel. But, aluminum has a low yield strength which causes the compressor wheel to expand outwardly at high rotational speeds such that the slip fit on the shaft no longer prevents wobble at high rotational speeds. To at least partially address this issue, the compressor wheel has two portions: an inner portion made of steel or titanium that has a relatively higher yield strength and a blade portion made of a lightweight, castable material. The inner portion is manufactured with grabbing features on its periphery, placed in a die, and the blade portion is cast over the grabbing features to yield a compressor wheel of two materials that provides sufficient shaft stiffening without high rotational inertia.

Abstract: An opposed-piston engine has a plurality of intake ports wrapped around the cylinder wall. It is desirable to obtain high swirl ratio flow with minimal pressure drop. A system have a generally-volute shaped plenum is disclosed. A centerline of the volute spirals inwardly. Furthermore, the cross-sectional area of the volute decreases in the direction of flow. The area is decreased as the flow from the plenum enters intake ports so that the velocity of flow in the plenum near the downstream end does not slow precipitously. The intake system may have multiple such volute-shaped plena coupled to mutually exclusive subsets of the intake ports. The volute shape leads to a high swirl ratio with limited drop in flow energy.

Abstract: An opposed-piston, opposed-cylinder engine in which the intake and exhaust pistons are symmetrically arranged has a small inertial force imbalance in the direction of reciprocation of the pistons. A center of gravity of the crankshaft can be displaced from the axis of rotation to at least partially overcome this imbalance. Such counterweighting of the crankshaft cancels a portion of the inertial balance due to the pistons but introduces an inertial imbalance in an orthogonal direction with respect to the piston-induced imbalance. By providing additional counterweights on pulleys rotating at the same speed, but the opposite direction, as the crankshaft, the imbalance can be substantially eliminated to yield substantially a perfectly-balanced engine.

Abstract: An engine system providing exceptional fuel efficiency is one that has two powerplants coupled by an electrically-actuated clutch. Packaging the two powerplants, the clutch, and the engine accessories presents a challenge. By driving the accessories via a shaft associated with the clutch, the accessories can be mounted between the two engines. Furthermore, this may facilitate providing one of each accessory rather than one per engine. The housing of the clutch is provided with tabs extending outwardly on which the accessories and associated components, such as mounting plates, mounting brackets, shafts, idler pulleys, tensioners, and pulleys, are mounted.

Abstract: A modular gear case assembly for an internal combustion engine is disclosed that includes a plate removably coupled to the block of the engine with a through hole in the plate through which an end of the crankshaft of the engine extends. The gear case is coupled to the plate and includes: a central gear that couples with the end of the crankshaft, a first interconnecting gear that meshes with the central gear, a second interconnecting gear that meshes with the central gear, a first side gear that meshes with the first interconnecting gear, a second side gear that meshes with the second interconnecting gear, a housing in which the gears are disposed, and a cover that sealingly couples with the housing.