A system is provided that includes a controller configured to determine one or more propulsion-generating vehicles in a group of propulsion-generating vehicles that have an increased risk for damage to an engine system based on operation at a fueling level that is less than a designated threshold fueling level for at least a designated time period. The controller is further configured to determine respective power outputs for the propulsion-generating vehicles in the group such that the one or more propulsion-generating vehicles having the increased risk for damage to the engine system do not operate below the designated threshold fueling level for longer than the designated time period.

A system is provided that includes a controller configured to determine one or more propulsion-generating vehicles in a group of propulsion-generating vehicles that have an increased risk for damage to an engine system based on operation at a fueling level that is less than a designated threshold fueling level for at least a designated time period. The controller is further configured to determine respective power outputs for the propulsion-generating vehicles in the group such that the one or more propulsion-generating vehicles having the increased risk for damage to the engine system do not operate below the designated threshold fueling level for longer than the designated time period.

Methods and systems are provided for reducing wall-wetting and improving mixing of air and fuel within a pre-chamber system of an engine. In one example, a method comprises supplying an air flow to the pre-chamber system via an air injector system while a piston associated with a main chamber is undergoing reciprocating motion. In this way, a rotating or swirling flow of fuel exiting a pre-chamber fuel injector of the pre-chamber system may be induced, which may reduce wall-wetting and improve air and fuel mixing, and when fuel is not being injected to the pre-chamber system the air flow may pressurize the pre-chamber system to reduce an amount of residuals from the main chamber to the pre-chamber system.

An internal combustion engine of reciprocating-piston type of construction is described which has a cylinder (2) with a cylinder head (1) and with an inlet valve (3) arranged in the cylinder head. An inlet line (4) is connected to the inlet valve (3), via which inlet line combustion air (5) can be fed to the cylinder (2). Furthermore, a compressed-air accumulator (6) is provided which is connected to the inlet line (4) by means of a controllable valve (7), wherein the inlet line (4) can be closed, with regard to its throughflow cross section, by means of a shut-off element (8). The valve (7) is controllable such that, on the basis of a control signal, compressed air (9) is fed from the compressed-air accumulator (6) into a region of the inlet line directly upstream of the inlet valve (3), wherein the shut-off element (8) is arranged sealingly on the cylinder head (1) and closes the cross section of the inlet line (4). The inlet valve (3) is briefly re-opened by means of an actuation element (24) during the compression stroke, and during said brief re-opening, compressed air (9) is fed from the compressed-air accumulator (6) into the cylinder (2), with the shut-off element (8) being held in its closed position. According to a second aspect, the compressed-air accumulator (6) can also be used to feed all of the combustion air to the cylinder (2) via an inlet reservoir (25) directly upstream of the inlet valve (3).

Methods and systems are provided for an engine having a pre-chamber ignition system. In one example, a method may include adjusting a valve coupled between a pre-chamber of an engine cylinder and a main chamber of the engine cylinder between a fully open position and a fully closed position based on whether pre-chamber ignition is desired or direct spark ignition is desired. In this way, the engine may be operated with direct spark ignition during conditions when pre-chamber combustion has reduced stability without including additional spark plugs and air injectors.

Methods and systems are provided for an engine having a pre-chamber ignition system. In one example, a method may include adjusting a valve coupled between a pre-chamber of an engine cylinder and a main chamber of the engine cylinder between a fully open position and a fully closed position based on whether pre-chamber ignition is desired or direct spark ignition is desired. In this way, the engine may be operated with direct spark ignition during conditions when pre-chamber combustion has reduced stability without including additional spark plugs and air injectors.

Methods and systems are provided for reducing wall-wetting and improving mixing of air and fuel within a pre-chamber system of an engine. In one example, a method comprises supplying an air flow to the pre-chamber system via an air injector system while a piston associated with a main chamber is undergoing reciprocating motion. In this way, a rotating or swirling flow of fuel exiting a pre-chamber fuel injector of the pre-chamber system may be induced, which may reduce wall-wetting and improve air and fuel mixing, and when fuel is not being injected to the pre-chamber system the air flow may pressurize the pre-chamber system to reduce an amount of residuals from the main chamber to the pre-chamber system.

A system is provided that includes a controller configured to determine one or more propulsion-generating vehicles in a group of propulsion-generating vehicles that have an increased risk for damage to an engine system based on operation at a fueling level that is less than a designated threshold fueling level for at least a designated time period. The controller is further configured to determine respective power outputs for the propulsion-generating vehicles in the group such that the one or more propulsion-generating vehicles having the increased risk for damage to the engine system do not operate below the designated threshold fueling level for longer than the designated time period.

A system is provided that includes a controller configured to determine one or more propulsion-generating vehicles in a group of propulsion-generating vehicles that have an increased risk for damage to an engine system based on operation at a fueling level that is less than a designated threshold fueling level for at least a designated time period. The controller is further configured to determine respective power outputs for the propulsion-generating vehicles in the group such that the one or more propulsion-generating vehicles having the increased risk for damage to the engine system do not operate below the designated threshold fueling level for longer than the designated time period.

A blowback air amount is an amount of air that is part of the air that has flowed into a combustion chamber and is blown back into an intake passage before an intake valve closes. If the blowback air amount increases, a controller causes a fuel injection valve to inject fuel by an amount increased with respect to a fuel amount for a case in which the blowback air amount remains constant. The controller sets an increase amount of fuel injected from the fuel injection valve to a greater value when the stoichiometric air-fuel ratio of the fuel injected from the fuel injection valve is small than when the stoichiometric air-fuel ratio of the fuel injected from the fuel injection valve is great.