Abstract: Methods and systems are provided for diagnosing a positive crankcase valve during a vehicle key-off event. In one example, a method may include controlling a fluid flow from a crankcase of an engine to an intake manifold of the engine via a positive crankcase ventilation valve, and indicating whether the positive crankcase valve is stuck open responsive to spinning the engine unfueled in a reverse direction, and indicating whether the positive crankcase valve is stuck closed responsive to spinning the engine fueled but without spark in a forward direction. In this way, functionality of a positive crankcase ventilation valve may be diagnosed effectively during key-off conditions, which may prevent or reduce engine complications arising from a stuck open or stuck closed positive crankcase valve.

Abstract: Methods and systems are provided for periodically activating a vehicle engine such that issues that may occur responsive to engine inactivity, such as rust and the sticking of components of the valve train, may be prevented. In one example, a vehicle engine increment off timer is used to monitor a duration wherein the vehicle engine has not been active, and responsive to expiration of the timer, spinning the engine unfueled in reverse while concurrently activating an onboard pump to direct air and fuel vapor to be stored in a fuel vapor canister. In this way, periodic engine lubrication operations may be conducted that do not require the use of fueled engine operation, thereby improving fuel economy and reducing undesired evaporative emissions.

Abstract: Methods and apparatus are described for a reciprocating combustion engine. A method includes operating a dual-piston engine including introducing a gas into a pair of combustion chambers; introducing a fuel into the pair of combustion chambers; compressing the gas; combusting the gas and the fuel; and exhausting combusted gases. Each of the pistons drives a reciprocating crankshaft that protrudes through a cylinder wall and cooperatively rotate a pair of rotors by engaging substantially sinusoidal cam tracks on the rotors. An apparatus includes a cam driven, concentric drive rotary-valve dual-piston engine.

Abstract: A scraper is provided in a large end portion of a connecting rod in an inclined type of overhead camshaft engine to lubricate a timing system by dipping a lubricating oil stored in a lower portion of a crank case up. The scraper includes a bottom wall and a side wall set up on the bottom wall, and have a substantially L-shaped cross-section. An angle between the bottom wall and the side wall is set in a range of 60° to 90°. Thus, the droplets of the oil can be splashed to the side direction of scraper also in three-dimensional inclined direction, so that oil can be securely supplied to and lubricate the timing system which is offset from the scraper in a longitudinal direction of the crankshaft.