Systems and methods for estimating when an engine event occurs is described. The system includes a controller configured to receive a first signal from at least one knock sensor coupled to a combustion engine, receive a second signal from at least one engine crankshaft sensor coupled to the combustion engine, transform the first and second signals into a plurality of feature vectors using a multivariate transformation algorithm, determine an expected window of an engine event with a statistical model, center a segment of the plurality of feature vectors around the expected window, estimate, using the statistical algorithm, a time in the expected window corresponding to when the engine event occurred, and adjust operation of the combustion engine based on the time.

An ignition timing control device has a knocking detection unit and an ignition timing adjustment unit. In a condition that the operation state of the internal combustion engine is suitable for adjustment of the ignition timing, the ignition timing control device outputs to an igniter an adjusted ignition signal as adjusted (corrected) by an adjusted ignition timing determination process. The ignition timing control device outputs to the igniter a reference ignition signal as it is outputted from an internal combustion engine control unit without adjustment (correction) in a condition that the operation state of the internal combustion engine is not suitable for adjustment of the ignition timing.

A lead-free piezoelectric ceramic composition includes a first crystal phase made of an alkali niobate/tantalate type perovskite oxide having piezoelectric properties, and a second crystal phase made of an M-TiO spinel compound (where the element M is a monovalent to quadrivalent element).

A pressure detection device includes: a cylindrical body made of a conductor; a pressure receiver made of a conductor, the pressure receiver being mounted to one end side of the body and receiving pressure from the outside; a signal generator arranged inside the body, the signal generator being electrically connected to the pressure receiver and generating a signal corresponding to the pressure received by the pressure receiver; and a cover made of an insulator with a lower thermal conductivity than thermal conductivities of the body and the pressure receiver, the cover continuously covering an outer surface of the pressure receiver and a portion of an outer surface of the body, the portion being located at a side closer to the pressure receiver.

The present invention provides an ignition timing control device and ignition timing control system for an internal combustion engine, capable of controlling an ignition timing of the engine promptly in response to a change in engine operating conditions. An ignition timing adjustment unit (43) is adapted to correct the ignition timing to a proper ignition timing in a retard region with reference to a maximum advance value based on a knocking signal outputted from a knocking detection unit (41) and a reference ignition signal (A) outputted from an external electronic control unit (37). The output signal from the ignition timing adjustment unit (43) can be thus promptly adjusted by retarding the ignition timing relative to a reference ignition timing given from the external electronic control unit (37) upon detection of engine knocking.

A non-resonant knock sensor includes: a sensor body having a metal shell provided with a shell-side cylindrical portion and a shell-side flange portion, a piezoelectric element, a weight arranged to hold the piezoelectric element between the shell-side flange portion and the weight and a fixing member having a third through hole through which the shell-side cylindrical portion is inserted and being arranged to press the weight toward the shell-side flange portion and thereby fix the weight in position; and a resin molded part. The fixing member has formed therein flow paths for introducing a resin into an inner space between the shell-side cylindrical portion and the piezoelectric element. The flow paths are provided in the form of at least one of being connected to the third through hole and being separated from the third through hole and are formed intermittently in a circumferential direction of the fixing member.

There is provided a pressure detection device including: a pressure detection element which receives pressure so as to output a detection signal corresponding to the pressure P; and a processing circuit which processes and outputs the detection signal output from the pressure detection element, where the processing circuit includes: a voltage transformation circuit which only transforms a power supply voltage fed from an external power supply so as to obtain a first reference voltage with a predetermined voltage value; an integrator circuit which uses the first reference voltage as an operation reference to perform integral processing on the detection signal so as to convert the detection signal into a voltage waveform; and at least one or more amplifier circuits which use a second reference voltage with a predetermined voltage value as an operation reference to perform amplification processing on an output signal from the integrator circuit.

A measurement amplifying circuit (400) for a piezo-electric sensor (100) positioned in an internal combustion engine supplying a signal to be measured, includes: a module (420) for generating a common mode voltage; a differential amplifier (410); and a subtraction module (430). The module (420) for generating a common mode voltage is to be connected to a wall (111) of the engine, the module (420) for generating a common mode voltage being suitable for supplying a common mode voltage signal (Vcm) reproducing the variations of an engine signal (Sb) received from the wall (111) of the engine.

Systems and methods for estimating an engine event location are disclosed herein. In one embodiment, a controller is configured to receive a signal from at least one knock sensor coupled to a reciprocating engine, transform the signal, using a multivariate transformation algorithm, into a power spectral density, transform the power spectral density into a plurality of feature vectors using predictive frequency bands, predict the engine event location using at least the plurality of feature vectors and a predictive model, and adjust operation of the reciprocating engine based on the engine event location.

Disclosed are a sensor for measuring seating force of an engine intake and exhaust valve and a measuring method. The sensor comprises a mounting boss, a force bearing element, a piezoelectric element, an annular thin-wall shell and an annular diaphragm with a T-shaped section. Meanwhile, the present disclosure also provides a measuring method by using the sensor. The sensor is simple in mechanism and convenient to use, has certain universality, and can realize the measurement of the impact load of the engine intake and exhaust valve.