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.

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).

When only smoke is generated, the sensor sensitivity is not substantially changed from the initial value. When both smoke and unburned HC are generated, the number of times the sensor sensitivity becomes lower than the initial value is increased. From these results, it can be understood that a deposit is formed in the presence of unburned HC and smoke existing simultaneously. The degree of reduction in sensor sensitivity becomes higher if the smoke concentration is increased when the unburned HC concentration condition is fixed. From this result, it can also be understood that while the coexistence of smoke and unburned HC is a prerequisite, unburned HC contributes largely to the formation of a deposit.

A glow plug including a substantially cylindrical housing extending in an axial direction; a rod-shaped heater unit having a front end protruding from the front end of the housing and movable in the axial direction; a connecting member connecting the heater unit to the housing within the housing and allowing the heater unit to move in the axial direction; and a pressure sensor that detects pressure received by the heater unit. The heater unit has a large-diameter portion at the rear end thereof and a small-diameter portion frontward of the large-diameter portion and having a diameter smaller than the diameter of the large-diameter portion. The connecting member connects the small-diameter portion of the heater unit to the housing within the housing.

A glow plug wherein a combustion gas prevention wall (67) extends radially outward on the outer circumferential surface of heater (10) such that when the heater (10) is viewed rearward from its forward end (10a) along the axial direction, the combustion gas prevention wall (67) closes an annular gap K1 at a position forward of annular membrane portion (63) of seal member (60). The combustion gas prevention wall (67) has an outer diameter D2 greater than the inner diameter D1 of forward end (136) of the housing.

An internal combustion engine, a method of operating the internal combustion engine, and a controller are disclosed. The method may be implemented in part by the controller and comprises determining a shaft angle of an engine shaft; supplying, to an ion sensor fluidly coupled to a combustion chamber of the engine a low voltage at a beginning of a combustion cycle to generate an ion sensor current and a high voltage during an ionization voltage window based at least in part on the shaft angle, wherein the low voltage is configured to prevent premature ignition of fuel in the combustion chamber and the high voltage exceeds the low voltage and is configured to increase the ion sensor current above a current threshold.

A method for transmitting data from a sensor to a receiver by means of an analog interface, whereby, during a first period of time, the sensor transmits identifier data for identifying the type of the sensor and/or for identifying the type of a component associated with the sensor, and measurement signals of the sensor are only transmitted after the first period of time. In this context, it is also provided that the transmission of the identifier data serves to identify a specific sensor from a group of multiple sensors and/or a specific component that is associated with the sensor from a group of multiple components, whereby the multiple sensors of the appertaining group and/or the multiple components of the appertaining group have mechanically identical interfaces and consequently can fundamentally be employed alternatingly. A method according to the invention is advantageously suitable, among other things, for transmitting data from a cylinder pressure sensor—which is especially integrated into a glow plug of an internal combustion engine—to a receiver, whereby this receiver can especially be integrated into a control unit, for instance, an engine control unit of the internal combustion engine. With such a method according to the invention, before measurement signals of the cylinder pressure sensor are transmitted, the engine control unit of the internal combustion engine can advantageously identify whether a defined, selected cylinder pressure sensor, and particularly a defined selected glow plug with an integrated cylinder pressure sensor, is also actually installed in the internal combustion engine.

Described is a method for regulating the temperature of a glow plug of an internal combustion engine, wherein a target resistance is determined from a target temperature by means of a resistance temperature characteristic of the glow plug and the actual resistance of the glow plug is regulated to the target resistance, the glow plug is heated to determine the resistance temperature characteristic of the glow plug, and thereby determining a resistance gradient and an electrical resistance of the glow plug is measured before the heating or at a defined time during the heating, using both the measured resistance and the resistance gradient, the resistance temperature characteristic is determined.

A method for transmitting data from a sensor to a receiver by means of an analog interface, whereby, during a first period of time, the sensor transmits identifier data for identifying the type of the sensor and/or for identifying the type of a component associated with the sensor, and measurement signals of the sensor are only transmitted after the first period of time. In this context, it is also provided that the transmission of the identifier data serves to identify a specific sensor from a group of multiple sensors and/or a specific component that is associated with the sensor from a group of multiple components, whereby the multiple sensors of the appertaining group and/or the multiple components of the appertaining group have mechanically identical interfaces and consequently can fundamentally be employed alternatingly. A method according to the invention is advantageously suitable, among other things, for transmitting data from a cylinder pressure sensor—which is especially integrated into a glow plug of an internal combustion engine—to a receiver, whereby this receiver can especially be integrated into a control unit, for instance, an engine control unit of the internal combustion engine. With such a method according to the invention, before measurement signals of the cylinder pressure sensor are transmitted, the engine control unit of the internal combustion engine can advantageously identify whether a defined, selected cylinder pressure sensor, and particularly a defined selected glow plug with an integrated cylinder pressure sensor, is also actually installed in the internal combustion engine.

A system and method to enable electronically controlled internal combustion engines to self-adjust parameters and operate properly on different fuels that have wide ranges of physical and chemical properties. Input from a sensor is utilized that gives a signal indicative of the combustion process. The ECU processes the signal and readjusts the engine operating parameters to achieve its operating goals.