An engine controller is configured to perform fuel cut-off, which temporarily stops fuel injection, calculate an in-cylinder air amount, which is an amount of air used for combustion in a cylinder, and control an engine based on the in-cylinder air amount. The engine controller includes a residual air amount calculation unit configured to calculate a residual air amount that is an amount of air in the cylinder remaining from a previous cycle during the fuel cut-off so that the residual air amount increases as the number of cycles of intake-exhaust actions in the cylinder increases during the fuel cut-off.

An internal-combustion engine includes an EGR device that recirculates a portion of exhaust gas, as EGR gas, from an exhaust passage to an intake passage through an EGR valve. A control device for the control device is configured to perform: EGR ratio estimation processing that calculates, by using an estimation model, an estimated EGR ratio; and estimation model update processing that updates the estimation model. The estimation model is configured to calculate the estimated EGR ratio based on a pressure parameter being a ratio of or a difference between gas pressures upstream and downstream of the EGR valve. The pressure parameter is represented by a pressure parameter model that is updatable. The estimation model update processing includes: calculating an actual EGR ratio; and updating the pressure parameter model such that the estimated EGR ratio becomes closer to the actual EGR ratio.

A control system of an engine is provided. The control system includes an exhaust variable valve mechanism for changing an operation mode of an exhaust valve, a fuel injection controlling module for controlling a fuel injector to inject fuel at a fuel injection timing associated with an operating state of the engine, a variable valve mechanism controlling module for operating the exhaust valve via the exhaust variable valve mechanism in a first operation mode when the operating state of the engine is within a compression self-ignition range, and in a second operation mode when the operating state of the engine is within a spark-ignition range, and a first in-cylinder state quantity estimating module for estimating a first state quantity inside the cylinder relating to a burned gas amount within the cylinder.

A method and apparatus for calculating an internal exhaust gas recirculation (EGR) amount of an engine include a continuously variable valve duration (CVVD) apparatus. The internal EGR amount is calculated by correcting a backflow gas amount based on a valve duration changed by operation of the continuously variable valve duration apparatus during valve overlap of an intake valve or an exhaust valve.

Methods and systems for supplying post injection fuel to a two stroke diesel engine are described. In one example, post injection fuel timing is adjusted responsive to an amount of internal residual combustion products in a cylinder so that less post injected fuel may be trapped in the cylinder for a subsequent cycle of the cylinder. The start of post injection fuel timing and the amount of post injection fuel may be adjusted responsive to internal residual in the cylinder.

A cylinder control module: selects one of N predetermined cylinder activation/deactivation patterns as a desired cylinder activation/deactivation pattern for cylinders of an engine, wherein N is an integer greater than two; and activates and deactivates opening of intake and exhaust valves of first and second ones of the cylinders that are to be activated based on the desired cylinder activation/deactivation pattern, respectively. A fuel control module provides fuel to the first ones of the cylinders and disables fueling to the second ones of the cylinders. The cylinder control module further: determines M possible ones of the N cylinder activation/deactivation patterns, wherein M is an integer greater than or equal to one; selectively compares the M possible cylinder activation/deactivation patterns with the desired cylinder activation/deactivation pattern; and selectively updates the desired cylinder activation/deactivation pattern to one of the M possible cylinder activation/deactivation patterns.

A control device of an engine including a cylinder, a piston, a cylinder head, and a combustion chamber is provided, which includes intake and exhaust ports, a swirl control valve provided in an intake passage connected to the intake port, a fuel injection valve attached to the cylinder head to be oriented into the center of the combustion chamber in a plan view thereof, and having first and second nozzle ports, and a control unit. The control unit includes a processor configured to execute a swirl opening controlling module to output the control signal to the swirl control valve to have a given opening at which a swirl ratio inside the combustion chamber becomes 2 or above, and a fuel injection timing controlling module to output the control signal to the fuel injector to inject fuel at a given timing at which the swirl ratio becomes 2 or above.

An engine includes an exhaust gas recirculation system with a high pressure exhaust gas recirculation loop and a low pressure exhaust gas recirculation loop, and an air charging system. A method of controlling the air charging system includes monitoring an actual exhaust gas recirculation rate, operating conditions of a compressor and turbine in the air charging system. A compressor flow is determined based on a target exhaust gas recirculation rate, a target intake manifold pressure and the actual exhaust gas recirculation rate. A power requested by the compressor is determined based on the compressor flow, the target intake manifold pressure, and the monitored operating conditions of the compressor. A power to be generated by the turbine is determined based upon the power requested by the compressor. A turbine flow is determined based upon the power to be generated by the turbine and the monitored operating conditions of the turbine. A system control command is determined based on the turbine flow and the monitored operating conditions of the turbine. The air charging system is controlled based on the system control command.

A method and system for operating an internal combustion engine equipped with a turbocharger and an exhaust gas recirculation pipe fluidly connecting an exhaust gas line to an air intake duct upstream of a compressor of the turbocharger is disclosed. A value of a parameter indicative of a temperature of an exhaust gas is determined, and an internal recirculation strategy of the exhaust gas is actuated if the determined value is lower than a predetermined threshold value thereof. The internal recirculation strategy includes interrupting a flowing of exhaust gas through the exhaust gas recirculation pipe, and opening an exhaust valve during an intake stroke of a piston of the internal combustion engine.

A method of calculating a residual gas mass in a cylinder of an internal combustion engine, wherein the cylinder has at least one intake valve and one exhaust valve, comprising: obtaining a cylinder residual gas mass base value that is based on a predefined model; determining a first cylinder residual gas mass value that indicates a cylinder residual gas mass remaining in the cylinder clearance volume after an expulsion of exhaust gas; determining a second cylinder residual gas mass value that indicates a cylinder residual gas mass flowing into the cylinder due to a valve overlap of the intake valve and the exhaust valve, wherein the second cylinder residual gas mass value is determined based on the cylinder residual gas mass base value and the first cylinder residual gas mass value; and calculating the residual gas mass in the cylinder, based on the first and second cylinder residual gas mass values.