A device for controlling purge of a vehicle includes: a state detector detecting state information to control purge of an engine; a controller generating an amount of fuel of each of cylinders of the engine using an amount of air of each cylinder, compensation information, a lambda control value, and an amount of a purge gas of the engine, checking a purge distribution coefficient according to an amount of an intake air for each cylinder when the state information satisfies a control entry condition, generating an amount of redistribution of the purge gas using the amount of the purge gas and the purge distribution coefficient, and generating an injection time for each cylinder using the amount of fuel, a conversion coefficient, and the amount of redistribution of the purge gas; and an injector injecting fuel in each cylinder during the injection time based on control of the controller.

A method of operating an engine is provided. An exhaust valve actuation fault is detected for a first exhaust valve associated with a first cylinder during a first working cycle. In response to the detection of the exhaust valve actuation fault, fueling to at least the first cylinder is cut off. Actuation of the first exhaust valve is attempted in second working cycles that follow the first working cycle, wherein the second working cycles are not fueled. Whether or not the first exhaust valve actuated properly during the second working cycles is determined. Operation of the first cylinder is resumed when it is determined that the first exhaust valve actuated properly. Operation of the first cylinder is not resumed when it is determined that the first exhaust valve did not actuate properly.

Systems and methods are provided for diagnosing cylinders in an engine. In one example, the method may include selecting a cylinder of the engine for perturbation, and while maintaining a horsepower output of the engine, perturbing the cylinder. Responsive to the perturbation of the cylinder inducing a crankcase pressure difference greater than or equal to a threshold difference, a degradation condition of the cylinder may be indicated. In one example, the perturbation may include cutting fuel to the cylinder. In one example, an engine load may be redistributed among each of remaining cylinder of a plurality of cylinders of the engine to maintain the horsepower output of the engine.

A straddled vehicle engine unit including an internal combustion engine and a misfire detection device. The misfire detection device includes a crankshaft rotation speed fluctuation physical quantity acquisition unit and a misfire determination unit. The misfire determination unit includes first to third determination units. The first determination unit determines whether or not the crankshaft rotation speed fluctuation physical quantity acquired by the crankshaft rotation speed fluctuation physical quantity acquisition unit is greater than a set physical quantity determination reference. The second determination unit determines whether or not a fluctuation pattern constituted by a physical quantity and the crankshaft rotation speed fluctuation physical quantity acquired at least before or after the physical quantity falls within a set misfire pattern range. The third determination unit determines whether a misfire determination is to be set as effective or not, based on results of determination by the first and second determination units.

A misfire detection device for an internal combustion engine is configured to execute: a deactivating process that deactivates combustion control for air-fuel mixture in one or some of cylinders; a provisional determination process that uses a detection value of a sensor to output a logical value indicating whether a misfire has occurred; a provisional determination counting process that counts a number of times a specific one of the logical value output by the provisional determination counting process has been output; and an official determination process that makes an official determination of whether the misfire has occurred using, as an input, the number of times counted by the provisional determination counting process during a specific period.

A determination device for an internal combustion engine executes a partial fuel cut-off process. The determination device determines that exhaust gas characteristics have deteriorated when the misfire rate of the internal combustion engine is greater than or equal to a determination threshold. The determination device sets the determination threshold to a first determination threshold when the calculated misfire rate is a misfire rate in a period of non-execution of the partial fuel cut-off process. Also, the determination device sets the determination threshold to a second determination threshold, which is less than the first determination threshold, when the calculated misfire rate is a misfire rate in a period of execution of the partial fuel cut-off process.

A method for carrying out the operation of an internal combustion engine, wherein liquid fuel injection amounts are injected at cylinders of a group of cylinders of the internal combustion engine in the context of injection events, wherein in a first step, a first cylinder of the group with the strongest knocking tendency over a time period is determined, and in a second step an injection correction occurs such that the injection events at the first determined cylinder can be sequentially reduced in their injection duration or injection amount by a first correction value, while the injection duration or injection amount of the injection events at the other cylinders of the group are sequentially increased by a second correction value.

A control device for an internal combustion engine is configured to carry out a lean combustion of which excess air factor is 2.0 or more by injecting fuel for creating a homogeneous air-fuel mixture from a first fuel injection valve into a combustion chamber of an engine main body, injecting ignition fuel for creating an ignition air-fuel mixture near an electrode portion of a spark plug from a second fuel injection valve, and igniting the ignition air-fuel mixture, and when occurrence of knocking is detected based on a detection value of a knock sensor during the lean combustion, apply retard correction to each of an ignition timing of the spark plug and an injection timing of the ignition fuel set corresponding to an engine operating state, and apply increase correction to an injection amount of the ignition fuel.

Misfire detection techniques for a hybrid electric vehicle (HEV) including an internal combustion engine and an electric motor involve utilizing a crankshaft speed sensor configured to generate a crankshaft speed signal indicative of a rotational speed of a crankshaft of the engine that is coupled to the electric motor via a flywheel. The techniques also utilize a controller configured to control the electric motor to provide a vibrational response to dampen disturbances to the crankshaft, receive the crankshaft speed signal, selectively modify the crankshaft speed signal to obtain a modified crankshaft speed signal, and detect a misfire of the engine based on the modified crankshaft speed signal and a set of thresholds including at least one of a negative misfire threshold and a positive vibrational response threshold.

Systems and methods for operating an engine with deactivating and non-deactivating valves are presented. In one example, a position of an engine air intake throttle is adjusted during cylinder deactivation to control intake manifold pressure for cylinder reactivation. Closing of the throttle may be timed based on an actual total number of cylinder induction events expected to provide a desired engine intake manifold pressure.