A failure diagnosis device for an in-cylinder pressure sensor includes an in-cylinder pressure sensor, and a controller comprised of circuitry configured to execute a diagnosis module into which a signal of the in-cylinder pressure sensor is inputted and configured to diagnose a failure of the sensor based on the signal. The diagnosis module includes a reading module configured to read the signals of the in-cylinder pressure sensor at a first timing that is a timing retarded by a specific crank angle from a compression top dead center, and at a second timing that is a timing advanced by the specific crank angle from the compression top dead center, and a failure determining module configured to determine that the in-cylinder pressure sensor has failed when the failure determining module determines that a difference between signal values at the first timing and at the second timing exceeds a predefined threshold.

A pressure sensor includes: a diaphragm joined to a front side of a housing via a joint portion; a sensor portion; a connection portion connecting the diaphragm to the sensor portion; and a heat receiving portion disposed at the front side of the diaphragm. When: a minimum value of an area of a minimum inclusion region which is a virtual region, which include a cross-section of a portion from the heat receiving portion to the diaphragm and of which an overall length of a contour become minimum on a cross-section perpendicular to the axial line, is defined as a connection area Sn; and an area of a region surrounded by the joint portion on a projection plane perpendicular to the axial line when the diaphragm and the heat receiving portion are projected onto the projection plane is defined as a diaphragm effective area Sd, (Sn/Sd)0.25 is satisfied.

A method for detecting a damaged-bearing in an engine using a vibration signal may include: separating, by a controller, a vibration signal of the engine detected by a vibration detecting device installed on one side of the engine of a vehicle into a vibration signal caused by combustion knocking and a vibration signal generated in a bearing, extracting a signal in a predetermined natural frequency band from the vibration signal generated in the bearing using a band-pass filter, and processing the extracted signal to a quantified bearing signal using the controller, and comparing the quantified bearing signal with a preset damaged-bearing criterion using the controller to determine whether the quantified bearing signal is equal to or higher than the preset damaged-bearing criterion to determine a damage to the bearing.

A system for inhibiting seizure of a bearing may include: a knocking sensor provided at one side of an engine to measure vibration transmitted from the engine and detect knocking of the engine, and a controller for controlling operation of the engine. In particular, the controller determines that a bearing of the engine is damaged when a magnitude of vibration of the engine inputted from the knocking sensor is greater than a damaged-bearing judging threshold value while the engine is operated in a damaged-bearing detecting region which is a region where knocking does not occur.

A method for predicting failure in a cylinder of a multi-cylinder engine is provided. Each cylinder has an associated pressure sensor to provide a signal indicative of pressure in the cylinder. The method includes identifying whether there is a non-fueling interval associated with any of the cylinder on the engine. The method includes determining at least one of parameters such as an indicated mean effective pressure, a peak cylinder pressure, a total heat released, or a total duration of heat released over a combustion cycle for the cylinder. The method includes comparing the at least one of the parameters with predefined threshold value, determining whether any of the parameters exceeds the predefined threshold value, and generating a signal indicating the impending cylinder failure if at least one of the parameters exceeds the corresponding predefined threshold value.

A method for detecting a damaged-bearing in an engine using a vibration signal may include: separating, by a controller, a vibration signal of the engine detected by a vibration detecting device installed on one side of the engine of a vehicle into a vibration signal caused by combustion knocking and a vibration signal generated in a bearing, extracting a signal in a predetermined natural frequency band from the vibration signal generated in the bearing using a band-pass filter, and processing the extracted signal to a quantified bearing signal using the controller, and comparing the quantified bearing signal with a preset damaged-bearing criterion using the controller to determine whether the quantified bearing signal is equal to or higher than the preset damaged-bearing criterion to determine a damage to the bearing.

An air-cooled engine capable of enhancing detection precision of a temperature sensor includes a crankcase, a crankshaft, a fan case, and an engine cooling fan. The installation direction of the crankshaft defines the front and rear direction. The fan case is provided in a front part of the crankcase, and the engine cooling fan is accommodated in the fan case. The air-cooled engine includes a cooling wind passage, a wind passage terminal end wall, an oil splashing device, and a temperature sensor. The wind passage terminal end wall is provided in a rear end of the cooling wind passage, the oil splashing device is provided on the rear side of the wind passage terminal end wall and formed to splash engine oil in the crankcase onto the wind passage terminal end wall, and the temperature sensor is attached to a front part of the wind passage terminal end wall.

The aim of the invention is to economically produce a pressure measuring sensor element, and relates, according to one aspect, to a method for producing a pressure sensor measuring element for a pressure sensor which comprises at least one membrane and a covering protecting the membrane, the pressure sensor element being produced in a layer-by-layer generative production method. This makes it possible to, for example, easily construct a combination sensor for detecting pressure and an additional parameter. It is also possible to structures for reinforcement or for influencing resonant frequency or for influencing heat conduction.

A method of determining combustion efficiency in an engine includes utilizing a control module having a computer memory, a processor, and inputs and outputs, the processor executing logic stored within the memory, sensing data by first sensors disposed on the engine and second sensors disposed in an exhaust system fluidly coupled to the engine, the first and second sensors electrically connected to the inputs, receiving within the control module data sensed by the first and the second sensors; determining an oxygen content of air entering the engine, determining an oxygen content of exhaust upstream of an oxidation catalyst; determining a fuel latent heat of vaporization; determining a fuel injection quantity to combust with oxygen entering the engine; determining a combustion efficiency index based on the oxygen content of air entering the engine and in the exhaust, and the latent heat of vaporization of fuel; and adjusting a fuel injection quantity.

An engine includes a cylinder pressure sensor inserted into a through-hole of a cylinder head. A sealing member that seals between a hole wall surface and a body-side wall surface. A dimension relationship of D1<D3(D4/D2) is satisfied where: D1 is a distance in a direction of a central axis from a reference position of the sealing member to a first given position; D2 is a distance between the hole wall surface and the body-side wall surface at the first given position; D3 is a distance in the direction of the central axis from the reference position to a second given position; and D4 is a distance between the hole wall surface and the body-side wall surface at the second given position.