A method of reducing cold start emissions in a series mode hybrid electric vehicle, including an internal combustion engine with an exhaust duct having a catalyst and a downstream oxygen sensor, an output of the combustion engine being connected to an electric generator with a power output of at least 10 kW that is connected to an electric motor which is coupled to a drive shaft of two or more wheels. The method includes detecting a cold start condition, injecting fuel into the engine such that combustion at a lambda value, λ, is achieved for which λ>1, running the engine at a speed of 1000 rpm or higher, determining if the efficiency of the catalyst reaches a first level, setting λ to about 1 after the predetermined efficiency level of the catalyst has been reached, and reducing the speed to working conditions when the catalyst efficiency reaches a second level.

A method includes: initiating a low engine-out NOx (LEON) mode by controlling a component of a vehicle having an aftertreatment system to decrease an instantaneous engine-out NOx (EONOx) amount; comparing a temperature of the aftertreatment system during the LEON mode to a warm-operation threshold temperature; responsive to determining that the temperature of the aftertreatment system exceeds the warm-operation threshold temperature, disengaging the LEON mode; responsive to determining that the temperature of the aftertreatment system is below the warm-up operation threshold temperature, comparing information indicative of an operating status of the vehicle to a LEON exit threshold; and disengaging the LEON mode responsive to determining that the information indicative of the operating status of the vehicle during the LEON mode exceeds the LEON exit threshold.

The present disclosure describes an engine system that can achieve at least one of the followings: suppressing of generating of nitrogen oxides and suppressing of remaining of uncombusted hydrocarbons. The engine system has a combustion chamber to which air and a gas fuel are supplied, and is configured to combust the gas fuel. The engine system includes a liquid fuel injecting unit, and a control unit. The liquid fuel injecting unit is configured to inject a liquid fuel thereby to ignite the gas fuel. The control unit is configured to control the liquid fuel injecting unit. The control unit is configured to control the liquid fuel injecting unit so that injection of the liquid fuel is performed after a flame propagation after ignition of the gas fuel is ended.

The present disclosure relates to a method for operating a combustion engine. A main amount of gas fuel is fed via a pre-chamber into a main combustion chamber. An ignition quantity of gas fuel is fed into the pre-chamber before the piston reaches the upper dead center to form an air-gas fuel mixture in the pre-chamber, which is fatter than in the main combustion chamber. The air-gas fuel mixture in the pre-chamber ignites itself. The air-gas fuel mixture in the main combustion chamber ignites through the self-ignited air-gas fuel mixture in the pre-chamber.

A method for controlling engine braking in a vehicle comprises: determining a position of a throttle operator; determining a speed of the vehicle; and determining an engine braking mode selected. In response to the position of the throttle operator being a fully released position and the selected braking mode being a first engine braking mode: controlling an engine and a position of a throttle valve according to the first engine braking mode for applying a first level of engine braking. In response to the position of the throttle operator being the fully released position and the selected braking mode being the second engine braking mode: controlling the engine and the position of the throttle valve according to the second engine braking mode based at least on the speed of the vehicle for applying a second level of engine braking. A vehicle implementing the method is also disclosed.

A method for controlling engine braking in a vehicle comprises: determining a position of a throttle operator; determining a speed of the vehicle; and determining an engine braking mode selected. In response to the position of the throttle operator being a fully released position and the selected braking mode being a first engine braking mode: controlling an engine and a position of a throttle valve according to the first engine braking mode for applying a first level of engine braking. In response to the position of the throttle operator being the fully released position and the selected braking mode being the second engine braking mode: controlling the engine and the position of the throttle valve according to the second engine braking mode based at least on the speed of the vehicle for applying a second level of engine braking. A vehicle implementing the method is also disclosed.

A method to estimate the temperature of an electromagnetic actuator, which entails a preliminary step in which to define a first threshold value for the current or for the voltage; and define a characteristic curve of the actuator family in the plane temperature/time needed to reach the threshold value; a step in which to carry out a reference measurement, in which, using the characteristic curve, a reference time needed by the electromagnetic actuator to reach the first threshold value is associated with a known reference temperature; and a step in which to carry out a series of measurements in which to determine the time needed by the electromagnetic actuator to reach the first threshold value, calculate the deviation between the time needed by the electromagnetic actuator to reach the first threshold value and the reference time; and determine the temperature of the electromagnetic actuator, using the characteristic curve, by associating the temperature of the electromagnetic actuator with the sum of the deviation and of the reference time.

A method of controlling an engine system includes controlling a fuel injector to perform a zero-fueling injector operation during operation of the engine, the zero-fueling injector operation including a non-zero injector on-time resulting in zero fueling by the injector, determining an injection system pressure change associated with the zero-fueling injector operation, modifying at least one fuel injection control parameter in response to the injection system pressure change, and using the modified fuel injection control parameter to control injection of fuel by the fuel injector during operation of the engine.

A method of controlling an engine system includes controlling a fuel injector to perform a zero-fueling injector operation during operation of the engine, the zero-fueling injector operation including a non-zero injector on-time resulting in zero fueling by the injector, determining an injection system pressure change associated with the zero-fueling injector operation, modifying at least one fuel injection control parameter in response to the injection system pressure change, and using the modified fuel injection control parameter to control injection of fuel by the fuel injector during operation of the engine.

Embodiments disclosed herein relate generally to systems and methods of operating internal combustion (IC) engines, and more specifically to systems and methods of starting compression ignition (CI) engines when the surrounding environment is significantly colder than the normal operating temperature of the engine (i.e., “cold-starting”). In some embodiments, the CI engine can include an ignition-assist device. In some embodiments, a method of operating a CI engine during cold-start can include opening an intake valve to draw a volume of air into the combustion chamber, moving a piston from a bottom-dead-center position to a top-dead-center position in a combustion chamber at a compression ratio of between about 15 and about 25, injecting a volume of fuel, the fuel having a cetane number of less than about 30, closing the intake valve, and combusting substantially all of the volume of fuel.