A method for operating a compression ignition engine includes forming a combustible mixture by mixing generally homogeneously a first fuel and air and introducing this mixture into the at least one cylinder, compressing the combustible mixture with the piston in a compression stroke, injecting a second fuel to the combustible mixture at an injection-time of the second fuel during the compression stroke but before start of combustion, and continuing the compression stroke until combustion starts at those locations in the at least one cylinder where concentration of the second fuel is highest and/or the temperature of the mixture is the highest. Emission of the cylinder and/or mechanical stress of the cylinder caused by the combustion are monitored, and if emissions and/or mechanical stress are above respective predetermined thresholds, individually for the cylinder, the amount and/or the timing of the second fuel injected, and/or temperature of the cylinder charge is changed.

The invention relates to a method of controlling a variable valve timing arrangement of an internal combustion engine, the variable valve timing arrangement being arranged to control the timing of an intake valve and an exhaust valve of the internal combustion engine, the method comprising: controlling the variable valve timing arrangement so as to delay the intake valve lifts and to advance the exhaust valve lifts in response to at least one parameter representative of a current load of the internal combustion engine passing a certain threshold value, thereby indicating that the internal combustion engine is operated in a low load state The invention relates also to a computer program product comprising program code for a computer for implementing a method according to the invention. The invention relates also to a control arrangement and a vehicle comprising the control arrangement.

Methods and systems are provided for protecting an exhaust catalyst from degradation during a DFSO event. Exit from DFSO due to pedal input received from an operator with a jittery foot is averted by filtering the pedal input differently when operating in a DFSO mode as compared to when operating out of the DFSO mode. Exit from DFSO is confirmed after receiving a higher than threshold pedal position input for a sustained period of time, or when an integrated fuel injection amount exceeds a threshold amount.

An engine system is provided, including a controller which estimates an intake-valve-closing temperature inside a cylinder. When an engine operates at a given speed and a demanded engine load is a first load or a second load (>the first load), the controller controls so that a mixture gas inside the cylinder combusts by compression ignition, and controls so that, at the first load, the entire mixture gas combusts by compression ignition when the intake-valve-closing temperature is above a first temperature, and at least part of the mixture gas combusts by flame propagation when the intake-valve-closing temperature is below the first temperature, whereas at the second load, the entire mixture gas combusts by compression ignition when the intake-valve-closing temperature is above a second temperature (<the first temperature), and at least part of the mixture gas combusts by flame propagation when the intake-valve-closing temperature is below the second temperature.

An engine system is provided, including a controller which controls devices of an engine at a given engine speed so that, when a demanded engine load is a first load, a mass ratio (G/F) of intake air inside a cylinder (containing fresh air and burnt gas) to fuel is a first G/F and mixture gas inside the cylinder combusts by flame-propagation, when the demanded load is a second load (<the first load), the G/F is a second G/F (>the first G/F) and an injection center-of-gravity is at a timing such that the entire mixture gas combusts by CI combustion, and when the demanded load is between the first and second loads, the G/F is at a third G/F (between the first and second G/Fs) and the injection center-of-gravity is at a later timing such that at least part of the mixture gas combusts by the CI combustion.

The disclosure concerns a method for vibration reduction in a compression ignition four- stroke internal combustion engine. The internal combustion engine comprises exhaust and intake valves controlled by exhaust and intake camshafts. The method comprises, when operating the internal combustion engine below a threshold rotational speed, steps of: changing a timing of the exhaust camshaft to advance closing of the exhaust valve, and - changing a timing of the intake camshaft to delay opening of the intake valve.

Methods and systems for unsticking a stuck gaspath actuator are disclosed. In one embodiment, an engine operating method includes adjusting exhaust valve timing of one or more cylinders of an engine in response to an indication that a gaspath actuator is stuck in position. In this way, pressure waves in an exhaust manifold and/or an intake manifold may be generated, which may act to unstick the gaspath actuator.

Methods and systems for operating an engine that includes an after treatment system are described. In one example, traffic data and navigation system data are a basis for deciding whether or not to increase heat output of an engine to ensure operation of the after treatment system. In particular, one or more actuators may be adjusted to minimize fuel consumption and/or reduce feedgas emissions while generating sufficient heat to maintain after treatment system operation.

Provided is an internal combustion engine control device capable of maintaining an activation temperature of a catalyst while suppressing deterioration of an exhaust gas in a hybrid engine. To this end, the internal combustion engine control device of the present invention controls an internal combustion engine in an engine for a hybrid vehicle. The internal combustion engine has a catalyst that purifies the harmful substances in the exhaust gas and a catalyst temperature detection unit that detects the temperature of the catalyst. Then, when the temperature of the catalyst detected by the catalyst temperature detection unit does not reach a predetermined temperature, the internal combustion engine control device performs a catalyst temperature rise control for increasing the temperature of the catalyst and performs motoring.

The disclosure concerns variable valve timing of a four-stroke ICE. The ICE comprises: an exhaust valve and an intake valve an exhaust camshaft an intake camshaft and a cylinder arrangement. The cylinder arrangement comprises a combustion chamber a cylinder bore and a piston. The control arrangement is configured to: perform a first sequence of changes in the timings of the exhaust and intake camshafts in order to arrive from a first camshaft timing setting at a second camshaft timing setting based on a first current maximum cylinder pressure within the combustion chamber around top dead centre fire and/or around to dead centre gas exchange.