An engine-knock controlling system for a carburetor-based engine includes one or more cylinders in which combustion occurs, wherein the system also includes a plurality of knock sensors coupled to an engine block, a first wiring harness, a first control unit, a second wiring harness, and a second control unit or an intermediate control unit, or a second control unit and intermediate control unit. The knock sensor(s) detects threatening engine-knock noise as an audible signal and transmits a signal through the wiring harnesses and control units to generate an ignition retarding action to correct the engine misfire and eliminate the knock/ping. Once the engine knock event is resolved, the processor of the first control unit transmits via the second wiring harness a signal to the second control unit or to the intermediate control unit, or to the second control unit and the intermediate control unit, to allow full-advance of ignition timing.

On an inner wall surface of a plug hole, an internal thread portion and a seat portion are formed. The seat portion has a tapered seat surface. A glow plug with a combustion pressure sensor includes a housing, a glow heater, a load transfer member, and a pressure detector. The housing has an external thread and a seat facing portion. The seat facing portion has a tapered contact surface in surface contact with the tapered seat surface. A recessed portion recessed to be in non-contact with the seat portion is formed annularly about a central axis of the housing.

On an inner wall surface of a plug hole, an internal thread portion and a seat portion are formed. The seat portion has a tapered seat surface. A glow plug with a combustion pressure sensor includes a housing, a glow heater, a load transfer member, and a pressure detector. The housing has an external thread and a seat facing portion. The seat facing portion has a tapered contact surface in surface contact with the tapered seat surface. A recessed portion recessed to be in non-contact with the seat portion is formed annularly about a central axis of the housing.

According to one or more embodiments presently described, a method of operating an internal combustion engine that includes injecting fuel into a combustion chamber to form an air-fuel mixture, where the combustion chamber includes a cylinder head, cylinder sidewalls, and a piston that reciprocates within the cylinder sidewalls. The method may also include detecting pre-ignition of the air-fuel mixture during a detected intake or compression stroke of the piston, determining that a super knock condition could occur, and mitigating formation of a super knock condition by deploying a super knock countermeasure within the detected compression stroke.

When a diesel engine is determined to be in a motoring state, a hysteresis zero angle H.sub.0 is determined (step S14). Subsequently, a gradient d.sub.n is calculated (step S16). The gradient d.sub.n is calculated based on data (θ.sub.n, Δh.sub.n) of a deviation Δh.sub.n at a retardation side from the hysteresis zero angle H.sub.0 and at an advance side from a predetermined crank angle. Subsequently, the gradient d.sub.n and the hysteresis zero angle H.sub.0 are updated (step S18). When the diesel engine is determined to be in a non-motoring state, data (θ.sub.n, P.sub.n) of an actual in-cylinder pressure is corrected based on a newest correction coefficient η and hysteresis zero angle H.sub.0 (step S22).

A control device for an internal combustion engine is provided that can detect the adherence of deposits to a cylinder pressure sensor without subjecting the internal combustion engine to an impact or the like. A control device for an internal combustion engine equipped with a cylinder pressure sensor detects changes in the sensitivity of the cylinder pressure sensor. If the control device detects a decrease in the sensitivity of the cylinder pressure sensor after detecting an increase in the sensitivity of the cylinder pressure sensor, the control device determines that deposits are adhered to the cylinder pressure sensor.

An internal combustion engine knock determining device includes a vibration detector that produces a signal corresponding to engine vibration, an intensity computing unit that retrieves vibrational components in a plurality of frequency regions in which vibration intensity peaks are located when knock occurs, a background-noise computing unit that calculates background noise caused by factors other than knock, a frequency computing unit that determines specific frequency regions from which to determine whether knock is occurring by excluding certain frequency regions designated as frequency regions requiring exclusion due to the intensity of false-detection causing noise as a proportion of the background noise in the certain regions, and a knock determining unit that determines the occurrence of knock based on the vibration intensity in the specific frequency regions obtained by excluding the frequency regions requiring exclusion, wherein the number of specific frequency regions is increased to improve the accuracy of knock detection.

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.

A pressure-sensor-integrated glow plug which can increase reliability of a bonding portion between a ceramic heater and a metal-made outer sleeve while being manufactured with relatively simple manufacturing steps and, at the same time, can maintain airtightness over a long period, and a method of manufacturing such a pressure-sensor-integrated glow plug.

A pressure-sensor-integrated glow plug which can increase reliability of a bonding portion between a ceramic heater and a metal-made outer sleeve while being manufactured with relatively simple manufacturing steps and, at the same time, can maintain airtightness over a long period, and a method of manufacturing such a pressure-sensor-integrated glow plug.