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DE-102024210911-A1 - Method for operating an internal combustion engine, control device and computer program product

DE102024210911A1DE 102024210911 A1DE102024210911 A1DE 102024210911A1DE-102024210911-A1

Abstract

Method for operating an internal combustion engine (10) in which gaseous fuel is directly injected into a combustion chamber (12) by a fuel injector (14) associated with the combustion chamber (12), and in which air is supplied to the combustion chamber (12) by at least one inlet valve (20), characterized in that at least temporarily at least a part of the gaseous fuel that is injected into the combustion chamber (12) during a working cycle is injected before the inlet valve (20) is closed, and that the amount of gaseous fuel that is injected before the inlet valve (20) is closed depends at least also on a setpoint for a filling of the combustion chamber (12) with air.

Inventors

  • Giovanni Cornetti
  • Maria Rosaria Gaballo
  • Gabriele Sgroi
  • Magda Elvira Cassone Potenza
  • Marino Iacobazzi

Assignees

  • Robert Bosch Gesellschaft mit beschränkter Haftung

Dates

Publication Date
20260513
Application Date
20241113

Claims (6)

  1. Method for operating an internal combustion engine (10) in which gaseous fuel is directly injected into a combustion chamber (12) by a fuel injector (14) associated with the combustion chamber (12), and in which air is supplied to the combustion chamber (12) by at least one inlet valve (20), characterized in that at least temporarily at least a part of the gaseous fuel that is injected into the combustion chamber (12) during a working cycle is injected before the inlet valve (20) is closed, and that the quantity (MB) of gaseous fuel that is injected before the inlet valve (20) is closed depends at least also on a target value for a filling (ML) of the combustion chamber (12) with air.
  2. Procedure according to Claim 1 , characterized in that a time difference between the start of the injection of fuel from the fuel injector (14) and the closing of the inlet valve (20) depends at least also on the target value for the filling (ML) of the combustion chamber (12) with air.
  3. Method according to at least one of the preceding claims, characterized in that the fuel is injected from the fuel injector (14) during a working cycle by a plurality of partial injections, and that the number of partial injections in the period before the closing of the inlet valve (20) depends at least also on the target value for the filling (ML) of the combustion chamber with air.
  4. Method according to at least one of the preceding claims, characterized in that a decision as to whether the fuel is injected from the fuel injector (14) during a working cycle by a single injection or a plurality of partial injections, at least one of which takes place in the period before the closing of the inlet valve (20), depends at least also on the target value for the filling (ML) of the combustion chamber with air.
  5. Control device (48) comprising a processor and a memory on which a computer program product is stored, which includes instructions which, when the computer program product is executed by the control device (48), cause it to execute a method according to one of the preceding claims.
  6. A computer program product that includes instructions which, when executed by a processor, cause the processor to execute a procedure according to one of the Claims 1 - 4 to execute.

Description

State of the art The invention relates to a method for operating an internal combustion engine, a control device and a computer program product. The DE 10 2021 210 001 A1 This describes a method for operating an internal combustion engine that runs on gaseous fuel, such as hydrogen. Gaseous hydrogen is injected directly into the combustion chambers, or it is injected into the intake ports (port fuel injection), and the hydrogen-air mixture is ignited in the combustion chambers by an ignition device. The hydrogen can be stored in liquid form under relatively high pressure in a tank-like fuel storage unit of the internal combustion engine's fuel system. From there, it passes in gaseous form via pressure regulating devices to a fuel rail, which is functionally similar to the fuel rail in an internal combustion engine with gasoline or diesel direct injection. Several fuel injectors are connected to the fuel rail, which deliver the gaseous fuel to the combustion chambers. Disclosure of the invention The problem underlying the invention is solved by a method, a control device, and a computer program product with the features of the dependent claims. Advantageous embodiments are specified in the subclaims. The invention allows the combustion chamber filling with air to be individually controlled for each cylinder and for each combustion cycle. In other words, the invention makes it possible to adjust the air mass flow into a cylinder individually for each combustion cycle by means of a suitable fuel injection pattern, thereby also influencing the lambda value, i.e., the fuel-air ratio. This results in more stable combustion and reduces undesirable emissions that might otherwise occur, for example, during transient operating conditions. It also prevents damage to a turbocharger compressor that could otherwise occur due to inertia or delay in the control of the filling process. Such damage includes, for example, excessively high engine speeds. This is achieved through a method for operating an internal combustion engine in which gaseous fuel is injected directly into the combustion chamber by a fuel injector assigned to that chamber. For this purpose, an outlet of the fuel injector opens directly into its corresponding combustion chamber. Hydrogen, for example, is a suitable fuel. The fuel-air mixture is ignited in the combustion chamber by an ignition device. The gaseous fuel can be stored in liquid form under relatively high pressure in a tank-like fuel storage unit of the internal combustion engine's fuel system. From there, it passes through various pressure regulating devices in gaseous form to a fuel rail, which is functionally similar to the fuel rail in an internal combustion engine with gasoline or diesel direct injection. Several fuel injectors are connected to the fuel rail, which inject the gaseous fuel directly into the corresponding combustion chamber. In the method according to the invention, air is supplied to the combustion chamber through at least one intake valve. Typically, the air is compressed upstream of the intake valve by a compressor of a turbocharger, and it can be cooled by an intercooler arranged downstream of the compressor. The total gas mass in the combustion chamber, which is available for combustion after the intake valve closes, thus consists, on the one hand, of the mass of the supplied air ("air charge" or "air filling") and, on the other hand, of the mass of the injected gaseous fuel. According to the invention, it is proposed that at least a portion of the gaseous fuel injected into the combustion chamber during a power cycle exits the fuel injector before the intake valve closes, at least temporarily. The gaseous fuel is thus injected into the combustion chamber at least during a suction stroke. Since the maximum volume of the combustion chamber is fixed at the end of an intake stroke (bottom dead center of the piston), the volume available for the air supply to the combustion chamber is reduced by the volume of fuel injected before the intake valve closes. The amount of gaseous fuel that exits the fuel injector and enters the combustion chamber before the intake valve closes thus influences the combustion chamber's air filling. According to the invention, the amount of gaseous fuel that enters the combustion chamber via the fuel injector before the inlet valve closes is at least also made dependent on a setpoint for the filling of the combustion chamber with air (the term "setpoint" is to be understood broadly). (and also includes all functionally equivalent quantities). By specifying a target value for the combustion chamber air fill, the amount of gaseous fuel injected into the combustion chamber before the intake valve closes is thus influenced. In other words, the ratio of the amount of gaseous fuel entering the combustion chamber before the intake valve closes, to the amount of gaseous fuel entering the combustion chamber after the intake valve closes, depends on this ta