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.

A lead-free piezoelectric ceramic composition mainly includes a first crystal phase (KNN phase) and a second crystal phase (NTK phase). In the first crystal phase (KNN phase), a plurality of crystal grains formed of an alkali niobate/tantalate perovskite oxide having piezoelectric characteristics is bound to each other in a deposited state. The second crystal phase (NTK phase) is formed of a compound containing titanium (Ti) and fills spaces between the crystal grains in the first crystal phase.

Disclosed is a method for forming a spacer extending at least partially within the length of a central bore passing from one side to the other of a barrel of a mounting base of an accelerometer sensor, the central bore being designed to receive a fastening element for fixing the mounting base onto a support element, the fastening element being centered by the spacer in the central bore, the mounting base being at least partially surrounded by an encapsulation of overmolded plastic material. When the plastic material is overmolded around the mounting base to form the encapsulation, a part of the plastic material passes through the barrel to form the spacer while fixing it to the encapsulation. Also described is a mounting base with at least one channel for the passage of the plastic material, and to an accelerometer sensor equipped with such a mounting base.

A method and control device for automatically identifying knocking in an internal combustion engine, wherein, in a predefined measurement time frame, a signal of the knocking sensor is received and evaluated with respect to a criterion for detecting knocking. A basic threshold value predefined for the identification of knocking is modified by a predefined variable interference factor, which depends on a relative point in time at which an inlet valve of at least one of the cylinders closes in relation to a predefined reference point. A signal based on the sensor signal is only identified as knocking if it reaches at least the modified basic threshold value.

The objective of the present invention is to remove drift of a piezoelectric element and thereby obtain a highly precise pressure detection signal by means of a simple configuration. A pressure detection signal processing device 200 includes: a charge amplifier 210 that accumulates electric charge produced by a piezoelectric element 35 in response to a received pressure and outputs a corresponding voltage signal; drift component extraction units 230 and 240 that extract a drift component of the piezoelectric element 35 by performing differential processing on the voltage signal; and a drift correction unit 250 that generates, based on the extracted drift component, a correction signal for removing the drift component and feeds the correction signal back to an input side of the charge amplifier.

An electrical connector includes two lateral mounting bush. A knock sensor which delivers data representative of the operation of a fuel injector is integrally overmoulded in one of the mounting bush. The knock sensor includes a piezoelectric member arranged between a base member and a seismic member.

A knocking sensor detecting vibration of an engine body and a pressure sensor detecting a pressure of a combustion chamber are provided. A value representing the knocking strength is acquired from output values of the pressure sensor. Weights of a neural network are learned using a value representing the vibration of the engine body detected by the knocking sensor as an input value of the neural network and using the acquired value representing the knocking strength as training data. The value representing the knocking strength is estimated from the output values of the knocking sensor by using the learned neural network.

An ignition timing control device for an internal combustion engine includes a storage device and a processor. The storage device stores a first learned neural network and a second learned neural network. The processor is configured to perform, in a next cycle where ignition timing is delayed, control to delay the ignition timing in a cycle after the next cycle based on a difference between a predictive value of an estimate of a value representing knocking intensity calculated with use of the second learned neural network and the estimate of the value representing the knocking intensity calculated with use of the first learned neural network. When the difference is larger than a predetermined set value, the processor is configured not to perform the control to delay the ignition timing in the cycle after the next cycle.

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.

An ignition timing control device includes bandpass filters each configured to pass and output only a specific frequency band for the output value of a knocking sensor, a storage device storing first learned neural networks configured to receive the output values of the bandpass filters in respective frequency band, and a processor. Each of the first learned neural networks is pre-learned to output an estimated value for a value representing knocking intensity when receiving the filtered output value of the bandpass filter. The processor calculates an optimal estimated value using a part of acquired estimated values for the value excluding a unique estimated value, and executes retarding control of an ignition timing based on the calculated optimal estimated value.