Methods and systems are provided for improving fuel economy and reducing undesired emissions. In one example, a method may include in response to an engine speed being within a first threshold speed of an engine idle speed during a speed reduction request with engine cylinders unfueled, maintaining the cylinders unfueled, and controlling the engine to a desired stopping position responsive to the engine speed being greater than a second threshold speed lower than the idle speed. In this way, fuel usage and emissions may be reduced and engine restart requests may be conducted at least in part via vehicle inertia.

An internal combustion engine (1) is provided with an exhaust particulate filter (6) disposed in an exhaust passage (4). When the particulate deposition amount and the temperature of the exhaust particulate filter (6) meet a predetermined excessive temperature rise condition, fuel cut during deceleration is prohibited. When a predetermined release condition is satisfied during the prohibition of the fuel cut, the fuel cut is temporarily permitted to perform the regeneration of the exhaust particulate filter (6).

An internal combustion engine (1) is provided with an exhaust particulate filter (6) disposed in an exhaust passage (4). When the particulate deposition amount and the temperature of the exhaust particulate filter (6) meet a predetermined excessive temperature rise condition, fuel cut during deceleration is prohibited. When a predetermined release condition is satisfied during the prohibition of the fuel cut, the fuel cut is temporarily permitted to perform the regeneration of the exhaust particulate filter (6).

Systems and methods are provided for controlling deceleration fuel shut off (DFSO) in response to an external object or location, such as a target vehicle. In one example, a method may include, while operating an engine in DFSO, determining a rate of change of a range to the target vehicle, and commanding an exit from the DFSO based on the range rate of change. By exiting the DFSO based on the range rate of change, torque lash experienced by a driver may be correspondingly reduced as compared to exiting the DFSO based upon, for example, one or more powertrain operating conditions.

In various aspects, internal combustion engines, engine controllers and methods of controlling engines are described. The engine includes a camshaft and a two cylinder sets. Cylinders in the first are deactivatable and cylinders in the second set may be fired at high or low output levels. The air charge for each fired working cycle is set based on whether a high or low torque output is selected. In some implementations, the camshaft is axially shiftable between first and second positions. First cam lobes are configured to cause their associated cylinders to intake a large air charge during intake strokes that occur when the camshaft is in the first position. Second cam lobes for cylinders in the second set cause their associated cylinders to intake a smaller air charge when the camshaft is in the second position. Second cam lobes for cylinders in the first set deactivate their associated cylinders.

A control device for a compression ignition engine is provided. At least in a high-load range where an engine load is higher than a given value, among an operating range where a partial compression ignition combustion is performed, an EGR valve is opened, and a first injection in which fuel is injected at least from an intake stroke to the first half of a compression stroke is carried out. While an engine body is operated in the high-load range, when a torque down request and a request for reducing external EGR gas amount introduced into the cylinder are issued, the opening of the EGR valve is reduced, and a second injection in which fuel is injected in the second half of the compression stroke is carried out, and a ratio of a fuel amount of the second injection to the total fuel amount injected in a combustion cycle is increased.

A system includes a fuel control module and a valve control module. The fuel control module controls a fuel injector to stop fuel delivery to each cylinder of an engine in a vehicle when the vehicle is decelerating. The valve control module controls a valve actuator to actuate intake and exhaust valves of each cylinder of the engine between open and closed positions when fuel delivery to each cylinder of the engine is stopped. The valve control module controls the valve actuator to adjust an amount of airflow through each cylinder of the engine to a minimum amount when fuel delivery to each cylinder of the engine is initially stopped. The valve control module controls the valve actuator to adjust the amount of airflow through each cylinder of the engine to an amount greater than the minimum amount before fuel delivery to each cylinder of the engine is restarted.

An internal combustion engine system includes an internal combustion engine, a controller, and an increased brake load event communicator. The internal combustion engine includes a first cylinder and a first cylinder deactivation prevention mechanism. The first cylinder is configured to be selectively activated and deactivated. The first cylinder deactivation prevention mechanism is configured to selectively prevent the first cylinder from being deactivated. The controller is communicable with the first cylinder deactivation prevention mechanism. The controller includes an increased brake load event detection module that is configured to selectively control the first cylinder deactivation prevention mechanism to prevent the first cylinder from being deactivated. The increased brake load event communicator is communicable with the controller. The increased brake load event detection module is configured to control the first cylinder deactivation prevention mechanism to prevent the first cylinder from being deactivated based on a communication from the increased brake load event communicator.

An internal combustion engine system includes an internal combustion engine, a controller, and an increased brake load event communicator. The internal combustion engine includes a first cylinder and a first cylinder deactivation prevention mechanism. The first cylinder is configured to be selectively activated and deactivated. The first cylinder deactivation prevention mechanism is configured to selectively prevent the first cylinder from being deactivated. The controller is communicable with the first cylinder deactivation prevention mechanism. The controller includes an increased brake load event detection module that is configured to selectively control the first cylinder deactivation prevention mechanism to prevent the first cylinder from being deactivated. The increased brake load event communicator is communicable with the controller. The increased brake load event detection module is configured to control the first cylinder deactivation prevention mechanism to prevent the first cylinder from being deactivated based on a communication from the increased brake load event communicator.

Systems and methods for providing charge to an energy storage system of a vehicle are provided. The method may include receiving, by a vehicle control system, an indication that a vehicle is coasting, slowing, and/or braking. Based on the received indication, engaging, by the vehicle control system, an electric motor coupled to an internal combustion engine to generate electric charge and provide the generated electric charge to the energy storage system, and while engaging the electric motor to generate electric charge, deactivating, by the vehicle control system, a cylinder of the internal combustion engine by maintaining an inlet valve of the cylinder and an exhaust valve the cylinder in a constant position, such as a closed position. In some instances, the inlet valve and exhaust valve may be maintained in an open state to further slow the vehicle.