A method for requirement-based servicing of an injector in a common-rail system in which, during ongoing operation of the engine, a current operating point is stored as a function of the rail pressure and of the fuel injection mass, and the current operating point is multiplied by a damage factor and is stored as a reference injection cycle as a function of the rail pressure as well as of the fuel injection mass. A total reference injection cycle is calculated by forming sums over the reference injection cycles, and a load factor is calculated as a function of the total reference injection cycle and the permissible injection cycles, and the load factor is set as decisive for the servicing recommendation of the injector.

An engine system includes: an engine including a direct injection valve that injects fuel into a cylinder of the engine and a port injection valve that injects fuel into an intake port of the engine; and an electronic control unit configured to control an operation of the engine by adjusting, based on a state of the engine, a rate of fuel injection from the direct injection valve with respect to total fuel injection and a rate of fuel injection from the port injection valve with respect to the total fuel injection. The electronic control unit executes a malfunction diagnosis with the rate of fuel injection from the direct injection valve set to 100%, when the electronic control unit determines that an execution condition for executing the malfunction diagnosis on a fuel system is satisfied and a power required of the engine is equal to or greater than a prescribed power.

A fuel injection system includes a first fuel injector having a first electronically-controlled valve and a first injection valve configured to inject fuel when the first electronically-controlled valve is actuated. A second fuel injector has a second electronically-controlled valve and a second injection valve configured to inject fuel when the second electronically-controlled valve is actuated. The fuel injection system also includes a single fuel injector driver configured to actuate the first electronically-controlled valve and the second electronically-controlled valve.

Various methods and systems are provided for health assessments of a fuel system. In one example, a fuel system includes a high-pressure fuel pump operable to increase fuel pressure from a first pressure to a second pressure, a common fuel rail fluidly coupling the high-pressure fuel pump to a plurality of fuel injectors each of which is operable to inject fuel to individual cylinders of an engine, a pressure sensor operable to detect a pressure of fuel at the common fuel rail, and a controller operable to diagnose a condition of the high-pressure fuel pump based on output from the pressure sensor.

A control device for a VCR connecting rod which can be operated by way of an actuation circuit is provided. Such a VCR connecting rod is to enable safe operation. For this purpose, a detection device is provided for determining a defect of the actuation circuit. Furthermore, the invention relates to a respectively associated method for operating an actuation circuit of a VCR connecting rod of an internal combustion engine.

A method for operating an internal combustion engine with multiple cylinders. Each cylinder of the internal combustion engine includes at least one fuel injector, and each fuel injector is activated for opening and closing via a solenoid valve of the respective fuel injector. Structure-borne sound waves emitted by the fuel injectors and/or accelerations caused by the fuel injectors are detected by measurement. The structure-borne sound waves detected by measurement and/or the accelerations detected by measurement are evaluated, and based on the evaluation, characteristics of the fuel injectors are automatically determined.

A spark plug electrode wearing rate estimating method for a spark plug in which spark discharge occurs between two electrodes by application of voltage generated by an ignition coil, includes the step of estimating a wearing rate of a first electrode in one spark discharge based on a temperature of the first electrode, and a spark discharge voltage and supply energy from the ignition coil. The first electrode contains any one of Ir, Ru, W, and Ni as a main component.

Methods and systems are provided for diagnostics of a cylinder valve actuation mechanism in a variable displacement engine (VDE). In one example, during an engine-off condition, the engine may be rotated unfueled, via a starter motor, and a reference exhaust air flow may be estimated. One or more deactivatable engine cylinders may then be deactivated and degradation of the cylinder valve actuation mechanism may be indicated based on a difference between the exhaust air flow following the cylinder deactivation and the reference exhaust air flow.

An emergency operation method for actuating a fuel pump after a first temperature threshold for an actuation electronics system of the fuel pump has been exceeded including reducing a power consumption of an electric motor that drives a pump stage by the actuation electronics system by reducing a rotational speed until a monitored temperature value falls below a second temperature threshold below the first temperature threshold. Emergency operation method is initiated after the first temperature threshold is exceeded by a fault signal output by the actuation electronics system to an engine control unit is communicatively connected to the actuation electronics system. The fault signal, as long as it is output, is used to suppress a specification for the rotational speed of the electric motor on the part of the engine control unit and instead to specify the rotational speed by way of the actuation electronics system.

Methods and systems for diagnosing operation of an exhaust gas recirculation system of an internal combustion engine are described. In one example, the EGR system is diagnosed while an engine that includes the EGR system is not rotating and combusting fuel. The EGR system is diagnosed when the engine is not operating so that vehicle passengers are not disturbed by the diagnostic and so that flow estimates through the EGR system may not be disturbed by pressure changes that may be related to combustion within the engine.