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.

A split cycle internal combustion engine includes a combustion cylinder accommodating a combustion piston and a compression cylinder accommodating a compression piston. The engine also includes a controller arranged to receive an indication of a parameter associated with the combustion cylinder and/or a fluid associated therewith and to control an exhaust valve of the combustion cylinder in dependence on the indicated parameter to cause the exhaust valve to close during the return stroke of the combustion piston, before the combustion piston has reached its top dead centre position (TDC), when the indicated parameter is less than a target value for the parameter; and close on completion of the return stroke of the combustion piston, as the combustion piston reaches its top dead centre position (TDC), when the indicated parameter is equal to or greater than the target value for the parameter.

To control a hybrid dynamical system, a predictive feedback controller formulates a mixed-integer nonlinear programming (MINLP) problem including nonlinear functions of continuous optimization variables representing the continuous elements of the operation of the hybrid dynamical system and/or one or multiple linear functions of integer optimization variables representing the discrete elements of the operation of the hybrid dynamical system. The MINLP problem is formulated into a separable format ensuring that the discrete elements of the operation are present only in the linear functions of the MINLP problem. The MINLP problem is solved over multiple iterations using a partial convexification of a portion of a space of the solution including a current solution guess. The partial convexification produces a convex approximation of the nonlinear functions of the MINLP without approximating the linear functions of the MINLP to produce a partially convexified MINLP.

A drive circuit (203) of an actuator (2) calculates an actual working angle from an actual operation quantity with reference to a reference table used to calculate a target operation quantity, and transmits the actual working angle and the actual operation quantity to a command unit (4). The command unit (4) determines whether or not the received values of the actual working angle and the operation quantity correspond to the valve working angle and the operation quantity of the reference table stored in the command unit (4), to detect a discrepancy between the operation modes of the actuator (2) and the command unit (4).

Systems and methods for operating an engine with deactivating valves are presented. In one example, a groove in a camshaft controls oil flow to a valve operator that selectively activates and deactivates a poppet valve of a cylinder. The groove moves with the camshaft so that oil delivery to the valve operator is timed properly to deactivate and reactivate the cylinder.

An internal combustion engine system includes a combustion cylinder provided with a reciprocating piston movable between a top dead center (TDC) and a bottom dead center (BDC) within the combustion cylinder. A first outlet valve is connected to the combustion cylinder for controllably directing exhaust gas from the combustion cylinder to a first exhaust gas manifold of the internal combustion engine system. A second outlet valve is connected to the combustion cylinder for controllably directing exhaust gas from the combustion cylinder to a second exhaust gas manifold of the internal combustion engine system. A turbocharger system includes a turbine and a compressor, wherein the turbine is arranged in fluid communication with the first exhaust gas manifold. An exhaust emission control device is arranged in fluid communication with the second exhaust gas manifold.

Disclosed is a combustion engine and method for engine braking therein including an intake air channel having a first pressure, a first inlet valve between the intake air channel and the cylinder volume, an exhaust air channel having a second pressure, a first outlet valve between the cylinder volume and the exhaust air channel, and a storage reservoir having a third pressure higher than the first and second pressures, the storage reservoir being arranged in controllable fluid communication with the cylinder volume. The method takes place during two-stroke cycle and includes: displacing the piston from upper dead centre (UDC) towards lower dead centre (LDC), keeping the first inlet valve open during at least part of the travel from UDC to LDC, displacing the piston from LDC towards UDC, and keeping the fluid communication between the storage reservoir and cylinder volume open during at least a part of such travel.

Methods and systems are provided for estimating a PCV flow to an engine based on the output of an exhaust gas oxygen sensor. During DFSO conditions, a reference voltage of the sensor is modulated initially with an intake throttle open and then with the intake throttle closed. PCV flow leaking past the piston valves in an aging engine, as well as an ambient humidity estimate, are inferred based on the outputs of the sensor during the modulating with the intake throttle open and closed.

An engine includes: a duration apparatus for adjusting an opening duration of an intake valve, a Cylinder De-Activation (CDA) apparatus for controlling deactivation of an exhaust valve, an igniter, an injector for injecting a fuel, an operation state signal unit for measuring an operation state of a vehicle, and a controller for controlling the operations of the duration apparatus, the CDA apparatus, the igniter, and the injector based on an output signal from the operation state signal unit. A control method for this engine includes: determining, by the controller, whether the operation state of the vehicle corresponds to a CDA operation mode; and when the CDA operation mode is determined, operating the CDA apparatus so as to stop the operations of the igniter and the injector, increase an opening duration of the intake valve, and deactivate the exhaust valve by controlling the CDA apparatus.

A control device for an engine, the engine includes an exhaust gas control apparatus that is configured to store NOx and react NOx with a reduction agent. The control device includes an electronic control unit. The electronic control unit is configured to: (i) execute a rich spike control, the rich spike control is a control executed to temporarily change an in-cylinder air-fuel ratio from a leaner air-fuel ratio than the stoichiometric air-fuel ratio to the stoichiometric air-fuel ratio or a richer air-fuel ratio than the stoichiometric air-fuel ratio, and (ii) vary an overlap amount of an intake valve and an exhaust valve such that the overlap amount is less during non-execution of the rich spike control than during execution of the rich spike control, in an operation range where a pressure of the intake port becomes higher than a pressure of the exhaust port.