Methods and systems are provided for adjusting operation of a split exhaust engine system based on a total flow of gases through a scavenge exhaust gas recirculation system of the split exhaust engine system. In one example, a method may include adjusting engine operation in response to a flow of gases to an intake passage, upstream of a compressor, from a scavenge manifold coupled to scavenge exhaust valves, the flow of gases determined based on a valve opening overlap between the scavenge exhaust valves and intake valves of an engine, the scavenge exhaust valves opened at a different time than blowdown exhaust valves coupled to a blowdown manifold coupled to a turbine.

A homogeneous charge compression ignition free-piston linear generator is disclosed. The linear generator includes a housing having cylinders at opposite ends. A double-ended piston assembly is to move linearly in the housing to convert kinetic energy of the piston assembly into electrical energy, and to enable conversion of electrical energy into kinetic energy of the piston assembly. Sensors measure one or more states of the cylinders and/or piston assembly, and a controller controls the linear generator based on the sensor data.

Methods and systems are provided for learning a cylinder-to-cylinder air variation. During conditions when a PFDI engine is operated in a port-injection only mode, prior to port fuel injection, a direct-injection fuel rail pressure may be lowered via direct-injection. Then, prior to a spark event in a port-injected cylinder, the direct-injector may be transiently opened to use the rail pressure sensor for estimating a cylinder compression pressure, and inferring cylinder air charge therefrom.

Methods and systems are provided for extending a duration of engine idle-stop while reducing a frequency of engine restart from idle-stop. In one example, in response to engine restart conditions where combustion torque is not necessary, an engine can be rotated electrically, without fuel delivery, via an electric motor. The unfueled engine spinning via the motor drives an FEAD which in turns drives an actuator coupled to the FEAD, such as an AC compressor or an automatic transmission oil pump.

In an internal combustion engine, fluctuations in combustion torque are suppressed to reduce vibration and prevent deterioration of ride comfort of a driver. Therefore, a control device of an internal combustion engine 100 having a plurality of cylinders 150 (a first cylinder 151, a second cylinder 152, a third cylinder 153, and a fourth cylinder 154) includes a combustion state detection unit for detecting whether the plurality of cylinders 150 are in a normal combustion state or a flame-out state, and a control device 1 which controls driving of a fuel pump 131 that is a load of a combustion torque generated by the cylinder 150. The control device 1 suppresses the driving of the fuel pump 131 at a predetermined combustion timing of the cylinders 151 to 154 of the flame-out state in a case where it is determined that any one of the cylinders 151 to 154 among the plurality of cylinders 150 is in the flame-out state.

A vehicle includes a variable displacement engine and a controller. The variable displacement engine has a plurality of cylinders and is configured to operate at a commanded air-fuel ratio. The controller is programmed to, in response to a command to perform a diagnostic test, operate the engine such that each of the cylinders is shut down for a portion of the diagnostic test while one or more of the remainder of the cylinders remain operating. The controller is further programmed to, in response to a deviation from the commanded air-fuel ratio exceeding a threshold while a first of the cylinders is shut down during the diagnostic test and a subsequent command to decrease the number of operating cylinders, shut down one or more of the plurality of cylinders other than the first of the cylinders.

One embodiment is a system comprising an engine including a dedicated EGR cylinder configured to provide EGR to the engine via an EGR loop, a non-dedicated cylinder, a plurality of injectors, an ignition system including a plurality of spark plugs, an intake throttle, and an electronic control system. The electronic control system is configured to control combustion during transient operation of the engine by determining one or more combustion control parameters compensating for variation of one or more of inert matter, unburned air and unburned fuel in EGR output by the dedicated EGR cylinder during transient operation of the engine, and an effect of the EGR loop on inert matter, unburned air and unburned fuel provided to the plurality of cylinders, and controlling operation of at least one of the throttle, the ignition system and the plurality of injectors in response to at least one of the one or more combustion control parameters.

Methods and systems are provided for measuring exhaust gas recirculation (EGR) distribution among individual engine cylinders. In one example, a method may include fluidly coupling a plurality of intake runners of an engine to a vacuum pump, diverting a portion of intake charge gas from the intake runner to a gas composition sensor with the vacuum pump, measuring an oxygen concentration of the diverted intake charge portion with the gas composition sensor, and estimating an EGR concentration of the intake charge based on the measured oxygen concentration.

A controller for controlling an internal combustion engine includes an injection amount calculation portion that calculates a base injection amount, an injection amount correction portion that corrects the base injection amount to calculate first and second corrected injection amounts, and an injection count determination portion that determines first and second fuel injection counts, which are respectively a number of times fuel is injected from first and second fuel injection valves. When the first and second corrected injection amounts are respectively calculated using the same base injection amount, the injection count determination portion sets the first fuel injection count corresponding to the first corrected injection amount to be equal to the second fuel injection count corresponding to the second corrected injection amount.

A system for detecting a fault condition in a valvetrain of an engine is configured to measure one or more operating parameters associated with the engine and determine if the operating parameters satisfy pre-defined corresponding boundary conditions. If so, a pair of values of at least one performance parameter is measured corresponding to measurement on a first and second bank of cylinders present on the engine. The difference between the pair of values is determined and used to compute at least one measure of variation for the at least one performance parameter in a time segment. If the at least one measure of variation for the at least one performance parameter exceeds a pre-defined limit for the engine, the valvetrain is flagged as faulty.