A method includes operating a spark ignition engine and flowing low pressure exhaust gas recirculation (EGR) from an exhaust to an inlet of the spark ignition engine. The method includes interpreting a parameter affecting an operation of the spark ignition engine, and determining a knock index value in response to the parameter. The method further includes reducing a likelihood of engine knock in response to the knock index value exceeding a knock threshold value.

An internal combustion engine has a combustion chamber, an intake tract through which air can flow, a first tank for a liquid spark-ignition fuel, a second tank for water, a mixing region, in which the spark-ignition fuel from the first tank is to be mixed with the water from the second tank thereby creating a mixture having the spark-ignition fuel and the water, an injection valve which is allocated to the combustion chamber and by which the mixture can be injected directly into the combustion chamber, and a second injection valve which is allocated to the combustion chamber and provided in addition to the injection valve and by which in relation to the water and the spark-injection fuel, only the spark-injection fuel from the first tank can be injected at a location upstream of the combustion chamber into the intake tract and thus into the air flowing through the intake tract.

Various embodiments include a method for operating a fuel injector comprising: applying a first current to a solenoid to perform a first injection process and inject a predefined injection quantity; determining a value of a system parameter indicating the relationship between the actual fuel quantity and the predefined quantity; determining, on the basis of the value of the system parameter, whether the actually injected fuel quantity is smaller than the predefined fuel quantity by a predefined amount corresponding to a disparity between a magnetic force exerted on the armature in the direction of the pole piece and an opposite hydraulic force exerted on the armature by fuel; and if it was determined that the quantities differ by enough, applying a second current to the solenoid to perform a second injection; wherein the second current exerts a lower magnetic force on the armature in the direction of the pole piece.

An internal combustion engine has a combustion chamber, an intake tract through which air can flow, a first tank for a liquid spark-ignition fuel, a second tank for water, a mixing region, in which the spark-ignition fuel from the first tank is to be mixed with the water from the second tank thereby creating a mixture having the spark-ignition fuel and the water, an injection valve which is allocated to the combustion chamber and by which the mixture can be injected directly into the combustion chamber, and a second injection valve which is allocated to the combustion chamber and provided in addition to the injection valve and by which in relation to the water and the spark-injection fuel, only the spark-injection fuel from the first tank can be injected at a location upstream of the combustion chamber into the intake tract and thus into the air flowing through the intake tract.

An internal combustion engine includes a fuel injection nozzle provided with a nozzle hole for injecting fuel, the nozzle hole exposed from a cylinder head of the internal combustion engine to a combustion chamber, and a hollow duct, an inlet and an outlet of which are exposed to the combustion chamber. The duct is provided in a manner allowing fuel spray injected from the nozzle hole of the fuel injection nozzle to pass through from the inlet to the outlet. The fuel injection nozzle and the duct are configured such that a part of fuel spray that is injected in pilot injection that is performed before main injection directly adheres to an inner wall surface of the duct.

An internal combustion engine includes a fuel injection nozzle provided with a nozzle hole for injecting fuel, the nozzle hole exposed from a cylinder head of the internal combustion engine to a combustion chamber, and a hollow duct, an inlet and an outlet of which are exposed to the combustion chamber. The duct is provided in a manner allowing fuel spray injected from the nozzle hole of the fuel injection nozzle to pass through from the inlet to the outlet. The fuel injection nozzle and the duct are configured such that a part of fuel spray that is injected in pilot injection that is performed before main injection directly adheres to an inner wall surface of the duct.

Various embodiments include a method for operating a fuel injector with a solenoid drive having a hydraulic stop at a predetermined fuel pressure comprising: applying a first current profile to the solenoid including a first holding current value prespecifying the current flowing during a holding phase; determining a resulting first flux; determining a first force based on the first flux corresponding to a hydraulic force exerted on the armature by fuel; determining a deviation between the first force and an optimal force corresponding to the predetermined fuel pressure; determining a second holding current based on the first holding current and the determined deviation; and applying a second current profile to carry out a second injection process using the second holding current value to apply a hydraulic force on the armature by the fuel adapted to the optimal force value.

Various embodiments include a method for operating a fuel injector with a solenoid drive having a hydraulic stop at a predetermined fuel pressure comprising: applying a first current profile to the solenoid including a first holding current value prespecifying the current flowing during a holding phase; determining a resulting first flux; determining a first force based on the first flux corresponding to a hydraulic force exerted on the armature by fuel; determining a deviation between the first force and an optimal force corresponding to the predetermined fuel pressure; determining a second holding current based on the first holding current and the determined deviation; and applying a second current profile to carry out a second injection process using the second holding current value to apply a hydraulic force on the armature by the fuel adapted to the optimal force value.

An internal combustion engine includes a fuel injection nozzle provided with a nozzle hole for injecting fuel, the nozzle hole exposed from a cylinder head of the internal combustion engine to a combustion chamber, and a hollow duct, an inlet and an outlet of which are exposed to the combustion chamber. The duct is provided in a manner allowing fuel spray injected from the nozzle hole of the fuel injection nozzle to pass through from the inlet to the outlet. The fuel injection nozzle and the duct are configured such that a part of fuel spray that is injected in pilot injection that is performed before main injection directly adheres to an inner wall surface of the duct.

Various embodiments include a method for operating a fuel injector comprising: applying a first current to a solenoid to perform a first injection process and inject a predefined injection quantity; determining a value of a system parameter indicating the relationship between the actual fuel quantity and the predefined quantity; determining, on the basis of the value of the system parameter, whether the actually injected fuel quantity is smaller than the predefined fuel quantity by a predefined amount corresponding to a disparity between a magnetic force exerted on the armature in the direction of the pole piece and an opposite hydraulic force exerted on the armature by fuel; and if it was determined that the quantities differ by enough, applying a second current to the solenoid to perform a second injection; wherein the second current exerts a lower magnetic force on the armature in the direction of the pole piece.