Knocking and pre-ignition are identified, without contributing to pre-ignition, even when vibration magnitudes and timings of occurrence of the knocking and pre-ignition are the same. When detecting an abnormal combustion that cannot be identified as a knocking or pre-ignition, ignition timing is advanced, at which time knocking is identified when an abnormal combustion intensity increases, and pre-ignition is identified when a difference between ignition timing and abnormal combustion occurrence timing increases.

An apparatus includes a base assembly, a gasket and a housing assembly. The base assembly may have a locking feature and a bearing feature. The locking feature may have a first passage in communication with an exterior of the apparatus. The gasket may be disposed on the base assembly and may have (i) a base portion, (ii) a column portion and (iii) a second passage in communication with the first passage. The housing assembly may have a sealing feature and may be configured to hold a sensor. The sealing feature (a) may mate with the bearing feature and (b) may compress the base portion of the gasket. The sensor (a) may seal to the column portion of the gasket and (b) may be in communication with the exterior of the apparatus through the first passage and the second passage.

Methods and systems are provided for determining engine knock sensor degradation. In one example, a method may include sending an excitation signal to an actuator to generate vibrations in the absence of engine combustion, and determining engine knock sensor degradation by comparing the knock sensor output with the excitation signal.

A method and a device for knock control of an internal combustion engine, a knock signal of a cylinder of the internal combustion engine being measured by a knock sensor and, on the basis thereof, a knock intensity is generated. The knock intensity is compared to a reference level in order to classify a combustion as a knocking or non-knocking combustion. Moreover, an arrangement is provided, which takes the level of the knock intensity into account for the determination of the reference level.

A disconnection detection circuit includes: a pull-up resistor to which the detection signal is fed and which connects a signal line connected to the wiring cable to a power supply or a pull-down resistor which connects the signal line to a GND; and a voltage clip circuit 105 which includes a high-voltage clip circuit which is connected between the signal line and the power supply and which clips the voltage of the signal line to the maximum specified voltage and a low-voltage clip circuit which is connected between the signal line and the GND and which clips the voltage of the signal line to the minimum specified voltage.

A method of monitoring an operating event of a combustion engine includes receiving a noise signal sensed by a knock sensor disposed in or proximate to the combustion engine, correlating the noise signal with a musical instrument digital interface (MIDI) fingerprint having at least an ADSR envelope indicative of the operating event, and detecting if the operating event has occurred based on the correlating of the noise signal with the fingerprint.

A cylinder internal pressure sensor includes: a housing; a diaphragm having flexibility and being joined to one end of the housing; a sensor element configured to change an output signal according to deformation of the diaphragm; and an opposed member housed inside the housing so as to face the diaphragm. The opposed member defines a housing room between the diaphragm and the opposed member, and includes: a cylindrical tube part being a layered structure with an inner tube and an outer tube; and a seal part provided inside the tube part. The sensor element is fixed to the seal part. The tube part is provided with a spring rate reducing portion that is provided between the diaphragm and a position where the inner tube and the outer tube are joined together.

Knocking and pre-ignition are identified, without contributing to pre-ignition, even when vibration magnitudes and timings of occurrence of the knocking and pre-ignition are the same. When detecting an abnormal combustion that cannot be identified as a knocking or pre-ignition, ignition timing is advanced, at which time knocking is identified when an abnormal combustion intensity increases, and pre-ignition is identified when a difference between ignition timing and abnormal combustion occurrence timing increases.

In a spark-ignition internal combustion engine having multiple cylinders, successive segment time periods assigned to the individual cylinders during working strokes thereof, and subsequently irregular running values are determined from the segment time periods. In a predefined speed range of the engine, the irregular running values of the cylinders are compared with a predefined threshold, and suspected auto-ignition for a first cylinder is detected if the irregular running value of a second cylinder located before the first cylinder in terms of timing of the ignition sequence undershoots the threshold. Fuel to the first cylinder suspected of auto-ignition is interrupted for a predefined number of cycles, and the fuel interruption influence on the irregular running values of the second cylinder during the cycles is detected. The suspected auto-ignition of the first cylinder is either confirmed or rejected based on the irregular running values occurring at the second cylinder.

There is provided a pressure detection device (10) including: a pressure detection element (21) which receives pressure (P) so as to output a detection signal (Qi) corresponding to the pressure (P); and a processing circuit (30) which processes and outputs the detection signal (Qi) output from the pressure detection element (21), where on a circuit board (40) on which a conductor pattern is formed, an integrated circuit (IC1) including an analog circuit which uses a reference voltage (Vr) set to a predetermined voltage value as an operation reference and converts the detection signal (Qi) into a voltage waveform is mounted, and the processing circuit (30) includes an input circuit 50 which feeds the detection signal (Qi) to the integrated circuit (IC1) and a shield pattern (SHP1) which surrounds the region of at least a part of the input circuit (50) and to which the reference voltage (Vr) is applied.