Methods and systems are provided for cylinder deactivation to reduce tailpipe emissions and increase exhaust temperature. In one example, a method may include operating a first set of cylinders in a first combustion cycle over modified eight strokes and a second set of cylinders in a second combustion cycle over modified four strokes. Each cylinder in the first set of cylinders may be selectively deactivated via a variable displacement engine (VDE) mechanism while each cylinder in the second set of cylinders may be selectively deactivated via an active decompression technology (ADT) mechanism.

Systems and methods for starting an engine of a hybrid vehicle are described. In one example, the method uses the engine to generate larger amounts of thermal energy while the engine is rotated under power of an electric machine. The systems and methods described herein may be applied to series and parallel hybrid vehicles.

A controller for a hybrid electric vehicle including an internal combustion engine is provided. The internal combustion engine includes a filter arranged in an exhaust passage collect particulate matter from exhaust gas. The controller executes a first deceleration control process, a second deceleration control process, and a selection process. The first deceleration control process uses a fuel cutoff process when deceleration of the hybrid electric vehicle is required. The second deceleration control process does not use the fuel cutoff process when deceleration of the hybrid electric vehicle is required. The selection process selects execution of the second deceleration control process when a PM deposition amount is greater than or equal to a threshold value and selects execution of the first deceleration control process when the PM deposition amount is less than the threshold value.

Engine systems which are safer and have reduced risk of fire are desirable in a wide range of equipment markets. The present engine systems utilize sensors and control systems which reduce the probability of fire or spark exiting the exhaust system. The sensors may monitor a wide range of conditions within the exhaust system to alter the operating parameters of the engine to prevent ignition of objects adjacent the engine system during use. By altering operation of the engine, conditions such as exhaust temperature or unburned fuel can be controlled to minimize risk of undesired ignition.

Methods and systems are provided for maintaining efficiency of a catalyst that is positioned in an exhaust system downstream of an internal combustion engine. In one example, the catalyst may be heated via supplying fuel to a cylinder that does not combust the fuel. The fuel may be oxidized at the catalyst via excess oxygen in the exhaust system.

An internal combustion engine with a plurality of cylinders is a drive device in which the drive torque available can be reduced. The ignition timing which is set at the internal combustion engine is adjusted in the retarded direction starting from an initial ignition timing until the ignition timing corresponds to a threshold ignition timing. To reduce the drive torque further, at least one cylinder, among the plurality of cylinders, is deactivated by suspending fuel injection into the cylinder, and the remaining cylinder(s) continue to be operated with fuel injection using the ignition timing. The remaining cylinders of the internal combustion engine which continue to be operated are supplied with a quantity of fuel which is larger in comparison with an initial quantity of fuel present before the cylinder deactivation, to set a substoichiometric fuel/oxygen ratio.

Methods and systems are provided for providing secondary air to an exhaust system during catalyst warm-up. In one example, a method may include, during a cold start condition, operating an engine with a first number of cylinders unfired and a remaining number of cylinders fired during an engine cycle, opening an intake valve of an unfired cylinder of the first number of cylinders during an expansion stroke of the unfired cylinder, and opening an exhaust valve of the unfired cylinder during a compression stroke of the unfired cylinder. In this way, the unfired cylinders may provide the secondary air to the exhaust system during a stroke that increases mixing of the secondary air with burned exhaust gas from fired cylinders, thus increasing exotherm production in the exhaust system to increase a temperature of the catalyst.

A method for controlling the operation of an engine system in a vehicle upon engine start. The engine system includes an engine and an exhaust aftertreatment system having a selective catalyst reduction, SCR, catalyst and a reductant dosing system for providing a reductant to the SCR catalyst. The method comprises: determining the temperature of the SCR catalyst; in response of determining that the temperature of the SCR catalyst is above a predetermined threshold, initiating pressurising of the reductant dosing system towards a predefined operating pressure; performing a preventive action for delaying engine start until the operating pressure of the reductant dosing system is reached.

Methods and systems are provided for re-combustion of exhaust in a cylinder of a multi-cylinder engine in order to increase the temperature of the exhaust for enhancing catalytic conversion within the multi-cylinder engine. In one example, a method may include expelling combusted gases from the cylinder into an intake manifold via an intake valve during an exhaust stroke, in order to rebreathe in the combusted gases from the intake manifold via the intake valve in a subsequent intake stroke.

A CPU prompts a user to drive a vehicle to a repair shop by operating a display when an amount of PM deposited in a GPF increases. When a regeneration request for the GPF is input from a shop-side terminal in the repair shop, the CPU performs a regeneration process in a state in which the vehicle stops. The CPU controls a temperature of the GPF such that the temperature at the time of execution of the regeneration process becomes lower when an opening/closing member is in a closed state than when the opening/closing member is in an open state.