A controller may identify an indication to initiate an engine braking procedure associated with an engine of a machine. The controller may obtain, based on identifying the indication to initiate the engine braking procedure, information relating to a requested amount of engine braking power of the engine. The controller may cause one or more components of a variable geometry turbocharger (VGT) of the engine to adjust, and a throttle valve of the engine to adjust, based on the information relating to the requested amount of engine braking power of the engine.

In a method and a device for operating an internal combustion engine, with at least one cylinder (Z1-Z4) having a combustion chamber (26), fuel is injected into the cylinder and a logic value (LV_FCUT) is set, in particular for stopping the injection of fuel into the cylinder, The method furthermore has the following steps: depending on a course of the highly time-resolved measurement signal of a rotational speed (N_FAST) of the internal combustion engine, a local maximum value (N_FAST_MAX) of the rotational speed is determined, a rotational speed difference (N_FAST_DIF) between the local maximum value (N_FAST_MAX) and a current measured value (N_FAST_MES) of the rotational speed is determined, and, depending on the determined rotational speed difference (N_FAST_DIF), the logic value (LV_FCUT) is set.

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.

A control device for an engine includes an ECU. The ECU is configured to: control an actual fuel pressure supplied to a fuel injector to a target fuel pressure; calculate a required energization time required for fuel injection equivalent in amount to a required injection quantity; set a energization time for each injection based on the required energization time; execute a switching processing for switching a manner in which the energization time is set when the required energization time is shorter than a predetermined time; set the required energization time as a set value of the energization time through the switching processing when a deviation between the actual fuel pressure and the target fuel pressure is equal to or larger than a predetermined value; and set the predetermined time as the set value of the energization time when the deviation is less than the predetermined value.

A control device for an engine includes an ECU. The ECU is configured to: control an actual fuel pressure supplied to a fuel injector to a target fuel pressure; calculate a required energization time required for fuel injection equivalent in amount to a required injection quantity; set a energization time for each injection based on the required energization time; execute a switching processing for switching a manner in which the energization time is set when the required energization time is shorter than a predetermined time; set the required energization time as a set value of the energization time through the switching processing when a deviation between the actual fuel pressure and the target fuel pressure is equal to or larger than a predetermined value; and set the predetermined time as the set value of the energization time when the deviation is less than the predetermined value.

A method of determining the cetane number of a fuel in an internal combustion engine comprising, during running of the engine, i) with respect to one cylinder, performing a routine including a series of injections such that for each injection a quantity of fuel is injected into the cylinder, and during the routine varying the angle at which the injections takes place with respect to crankshaft angle; ii) measuring engine speed at intervals during the series of injections and determining values for changes in engine speed consequent to the injections; iii) determining cetane number from a pre-stored relationship relating the cetane number to changes in engine speed consequent to changes in the test injection angle.

A control device of an internal combustion engine is configured to perform a fuel cut-off control and an abnormality diagnosis control. A heating device for heating an element of an air-fuel ratio sensor is controlled by making an element temperature of the air-fuel ratio sensor become a target element temperature. The target element temperature of the air-fuel ratio sensor during a high temperature control period from a time when a prescribed high temperature control begins after a start of the internal combustion engine to a time when the prescribed high temperature control is completed after completion of the abnormality diagnosis control of the air-fuel ratio sensor is set to be higher than the target element temperature outside the high temperature control period.

An internal combustion engine mounted on a vehicle includes an exhaust passage provided with a catalyst. A controller for the internal combustion engine includes a processor. The processor is configured to perform an auto-stopping process on the engine when the engine is idling, perform an auto-restarting process on the engine when the engine is automatically stopped, correct an amount of fuel injected into the engine so that the fuel injection amount of the engine is increased by a correction amount after the auto-restarting process is started, and change the correction amount in accordance with an amount of oxygen stored in the catalyst at a point of time when the auto-stopping process is started.

Methods and arrangements for transitioning an engine between a deceleration cylinder cutoff (DCCO) state and an operational state are described. In one aspect, transitions from DCCO begin with reactivating cylinders to pump air to reduce the pressure in the intake manifold prior to firing any cylinders. In another aspect, transitions from DCCO, involve the use of an air pumping skip fire operational mode. After the manifold pressure has been reduced, the engine may transition to either a cylinder deactivation skip fire operational mode or other appropriate operational mode. In yet another aspect a method of transitioning into DCCO using a skip fire approach is described. In this aspect, the fraction of the working cycles that are fired is gradually reduced to a threshold firing fraction. All of the working chambers are then deactivated after reaching the threshold firing fraction.

An apparatus for controlling an internal combustion engine is provided. An engine includes a compression release mechanism and a fuel injection valve. The compression release mechanism variably controls the opening degree of a valve member, and thereby connects the combustion chamber of the engine with at least one of the intake passage and the exhaust passage in order to release in-cylinder pressure during at least the compression stroke. A controller controls the fuel injection valve to execute coasting with the fuel cut off in which the fuel is cut off under a predetermined condition, and while executing coasting with the fuel cut off, controls the compression release mechanism to increase the opening degree of the valve member of the compression release mechanism as the speed of the engine is higher.