The present disclosure provides an apparatus for testing spray and combustion performance of an internal-combustion engine based on a rapid compression-expansion machine, which belongs to the testing field of internal-combustion engines. It includes a driving mechanism, a transmission mechanism, an engine cylinder, an air intake system and an exhaust system. The engine cylinder includes a piston, a cylinder block, a dual-fuel cylinder head and a multi-injector assembly. The piston is disposed in the cylinder block. The driving mechanism is connected with the piston through the transmission mechanism and drives the piston to linearly move back and forth along a vertical direction of the cylinder block. The dual-fuel cylinder head is connected to an upper part of the cylinder block. The multi-fuel injection assembly includes a plurality of injectors. The plurality of injectors are of the same type and are all disposed on the dual-fuel cylinder head.

A computer-implemented method for ascertaining a closure point in time of an injector of an internal combustion engine using a classifier. The method includes: ascertaining a time series of input signals, each corresponding to a point in time within the time series, and each characterizing a deformation of the injector; ascertaining a plurality of first values using the classifier based on the time series, in each case a first value corresponding to a point in time of the time series, and the first value characterizing a probability that the closure point in time of the injector matches the point in time; ascertaining a plurality of second values, each being a sum of neighboring first values, of a first value and the first value, the second value corresponding to the point in time to which the first value corresponds; ascertaining the closure point in time based on the largest second value.

A computer-implemented method for ascertaining a closure point in time of an injector of an internal combustion engine using a classifier. The method includes: ascertaining a time series of input signals, each corresponding to a point in time within the time series, and each characterizing a deformation of the injector; ascertaining a plurality of first values using the classifier based on the time series, in each case a first value corresponding to a point in time of the time series, and the first value characterizing a probability that the closure point in time of the injector matches the point in time; ascertaining a plurality of second values, each being a sum of neighboring first values, of a first value and the first value, the second value corresponding to the point in time to which the first value corresponds; ascertaining the closure point in time based on the largest second value.

A method and system for cleaning a fuel nozzle during engine operation is provided. Operations include operating the compressor section to provide the flow of oxidizer at a first oxidizer flow condition to the combustion chamber, wherein the first oxidizer flow condition comprises an environmental parameter; operating the fuel system at a first fuel flow condition to produce a fuel-oxidizer ratio at the combustion chamber; comparing the environmental parameter to a first environmental parameter threshold; and transitioning the fuel system to a second fuel flow condition corresponding to a cleaning condition at the fuel nozzle if the environmental parameter is equal to or greater than the first environmental threshold.

An alignment system includes an optical sensor device that may be inserted into a passage of a body that is located between a fuel injector and a combustion chamber of an engine cylinder. The body is shaped to transmit fuel ejected from a spray hole in a fuel injector into the combustion chamber of the engine cylinder. The system also includes a controller that may examine output of the optical sensor device and determine whether the passage of the body is aligned with the spray hole of the fuel injector based on the output from the optical sensor device. The controller may change a position of one or more of the body or the fuel injector responsive to determining that the passage of the body is not aligned with the spray hole of the fuel injector.

An alignment system includes an optical sensor device that may be inserted into a passage of a body that is located between a fuel injector and a combustion chamber of an engine cylinder. The body is shaped to transmit fuel ejected from a spray hole in a fuel injector into the combustion chamber of the engine cylinder. The system also includes a controller that may examine output of the optical sensor device and determine whether the passage of the body is aligned with the spray hole of the fuel injector based on the output from the optical sensor device. The controller may change a position of one or more of the body or the fuel injector responsive to determining that the passage of the body is not aligned with the spray hole of the fuel injector.

The invention relates to a maintenance system for a fuel injection system provided in an internal combustion engine, the fuel injection system defining a hydraulic circuit having a high-pressure pump, a solenoid valve, a pressure sensor, a metering solenoid valve, a common rail and injectors. The maintenance system includes a manual control unit connected to a hydraulic unit, the hydraulic unit being capable of being inserted into the hydraulic circuit of the fuel injection system and including a test solenoid valve and a test pressure sensor mounted in a body provided with an inlet mouth, an outlet mouth and a leakage mouth.

The invention relates to a maintenance system for a fuel injection system provided in an internal combustion engine, the fuel injection system defining a hydraulic circuit having a high-pressure pump, a solenoid valve, a pressure sensor, a metering solenoid valve, a common rail and injectors. The maintenance system includes a manual control unit connected to a hydraulic unit, the hydraulic unit being capable of being inserted into the hydraulic circuit of the fuel injection system and including a test solenoid valve and a test pressure sensor mounted in a body provided with an inlet mouth, an outlet mouth and a leakage mouth.

A method for identifying a type of a fuel injector installed in an internal combustion engine includes generating a control signal to supply electrical energy from a power source for actuating the fuel injector, monitoring the electrical energy, identifying a pattern in the electrical energy, the pattern being indicative of the type of the fuel injector, and outputting a notification indicative of an incorrect injector type based on the pattern.

A fuel injector testing machine is provided. The machine includes a head unit having a flow meter, and a fuel injector holding assembly. The head unit and/or the fuel injector holding assembly can be moved relative to each other, allowing the head unit to test a subset of fuel injectors held on the fuel injector holding assembly, and subsequently can test another subset of the fuel injectors via movement of the head unit and/or fuel injector holding assembly.