A method, system, and apparatus use infrared spectrometry onboard an internal combustion engine running on a natural gas fuel to detect characteristics of the fuel. At a site having a plurality of natural gas engines, detection of natural gas fuel components and concentrations of the components also is conducted at the site upstream of the point of intake of the natural gas fuel to one or more of the engines. Operating parameters of the engine or a plurality of the engines may be controlled on the basis of the detected composition of the natural gas fuel.

Methods and systems are provided for detection of cylinder misfire in an engine. In one example, a system may comprise a first cylinder and second cylinder of the engine having exhaust flows combined together in an exhaust system before being combined with other cylinders of the engine. The first cylinder and second cylinder may share an exhaust gas sensor mounted in the exhaust in a position to sense exhaust from the first cylinder and second cylinder, and being positioned before exhaust from other cylinders is combined with sensed exhaust from the first cylinder and second cylinder. The system may further include a control system with instructions stored therein to indicate detected misfire in one or more of the first and second sensors based on an output from the exhaust gas sensor.

The embodiment relates to a method for detecting a power-changing manipulation of an internal combustion engine (100), wherein the internal combustion engine (100) has an intake tract (110) and a pressure sensor (116, 118) which is arranged in the intake tract (110). The method has the following steps: acquiring a signal profile (440) over a specific time period by means of the pressure sensor (116, 118), providing a modelled signal profile (430) over the specific time period, from which periodically repeating modelled signal profile sections (432) which are characteristic of expected periodically repeating pressure changes in the intake tract (110) are ascertained, comparing a signal portion of an acquired signal profile section (442) with the corresponding signal portion of the corresponding modelled signal profile section (432) in order to detect the power-changing manipulation of the internal combustion engine (100).

A compression monitoring system for a reciprocating engine includes a controller configured to terminate combustion within a combustion chamber of the reciprocating engine while a crankshaft of the reciprocating engine is rotating. The controller is also configured to receive an input signal from a sensor indicative of vibration within a cylinder extending from the combustion chamber while the crankshaft is rotating and the combustion is terminated. Furthermore, the controller is configured to determine a magnitude of the vibration within a frequency range and to determine a maximum pressure within the cylinder based on the magnitude of the vibration within the frequency range. The controller is also configured to output an output signal indicative of the maximum pressure within the cylinder and/or control operation of the reciprocating engine based on the maximum pressure within the cylinder.

A feedback device for use in a gas turbine engine, and methods and systems for controlling a pitch for an aircraft-bladed rotor, are provided. The feedback device is composed of a circular disk and a plurality of position markers. The circular disk is coupled to rotate with a rotor of the gas turbine engine, to move along a longitudinal axis of the rotor, and has first and second opposing faces defining a root surface that extends between and circumscribes the first and second faces. The plurality of position markers extend radially from the root surface, are circumferentially spaced around the circular disk, and extending along the longitudinal axis from a first end portion to a second end portion. At least part of the first end portion and/or of the second end portion comprises a material having higher magnetic permeability than that of a remainder of the position markers.

A method for operating a drive device having a drive unit producing exhaust gas and an exhaust gas posttreatment device designed as a vehicle catalytic converter for posttreatment of the exhaust gas. A first measured value describing the residual oxygen content in the exhaust gas is measured by a first lambda sensor arranged upstream of the exhaust gas posttreatment device and a second measured value describing the residual oxygen content in the exhaust gas is measured by a second lambda sensor arranged downstream of the exhaust gas posttreatment device. The combustion air ratio of a fuel-air mixture used to operate the drive unit is set during an at least temporarily performed normal operating mode on the basis of the first measured value, the second measured value, and a threshold value for the second measured value.

In an internal combustion engine control apparatus, an electronic control device is configured to subject a signal from a knock sensor to short-time Fourier transform, to thereby generate an observation matrix. Further, the electronic control device is configured to decompose the observation matrix into knocking vibration data being data on vibration caused by knocking and mechanical vibration data being data on vibration other than the knocking.

There is provided a blade angle feedback system for an aircraft-bladed rotor rotatable about a longitudinal axis and having an adjustable blade pitch angle. A feedback device is coupled to rotate with the rotor and to move along the axis with adjustment of the blade pitch angle. The feedback device comprises a body having position marker(s) embedded therein, the body made of a first material having a first magnetic permeability and the position marker(s) comprising a second material having a second magnetic permeability greater than the first. Sensor(s) are positioned adjacent the feedback device and configured for producing, as the feedback device rotates about the axis, sensor signal(s) in response to detecting passage of the position marker(s). A control unit is communicatively coupled to the sensor(s) and configured to generate a feedback signal indicative of the blade pitch angle in response to the sensor signal(s) received from the sensor(s).

A diagnostic tool diagnoses a charge cycle behavior of an internal combustion engine with a plurality of cylinders. The diagnostic tool ascertains a rotational speed profile of the internal combustion engine. From the determined rotational speed curve, the diagnostic tool ascertains a peculiarity of at least one charge exchange characteristic variable by performing a Fourier transform. The diagnostic tool assigns a deviation type to the rotational speed profile as a function of the ascertained peculiarity of the charge exchange characteristic variable.

A method for detecting damage to a bearing of an engine using a knocking sensor includes a data storing step, which stores a vibration signal output from the knocking sensor in a data storing unit, a by-frequency amplitude calculating step, which performs Fast Fourier Transform (FFT) for the vibration signal and calculates an amplitude for each frequency, a detection frequency integrating step, which obtains a detection frequency integration value by adding all amplitudes of detection frequencies, a noise determining step, which determines whether the vibration signal is the vibration signal irrelevant to damage to the bearing by determining whether exclusion frequencies correspond to a preset condition, a counter increasing step, which increases a damage counter, when the detection frequency integration value is greater than a preset damage threshold, and a damage confirming step, which confirms damage to the bearing, when the damage counter equals or exceeds a preset confirmation counter.