Capacitive Ignition System Research Articles

The Tolerance Control of Capacitive Ignition Systems Ignition Capacity with Semiconductor Spark Plugs

The Tolerance Control of Capacitive Ignition Systems Ignition Capacity with Semiconductor Spark Plugs

Methods of Enhancing the Ignition Capacity of Capacitive Ignition Systems under Conditions of High-Altitude Launches of Aircraft Engines

Methods of Enhancing the Ignition Capacity of Capacitive Ignition Systems under Conditions of High-Altitude Launches of Aircraft Engines

СОВЕРШЕНСТВОВАНИЕ СРЕДСТВ КОНТРОЛЯ ЭФФЕКТИВНОСТИ СИСТЕМ ЗАЖИГАНИЯ АВИАЦИОННЫХ ДВИГАТЕЛЕЙ

Relevance Aircraft engine ignition systems are one of the main elements that determine the reliability of the operation of the aircraft as a whole. Evaluating and monitoring the performance of such systems must be carried out at stages from development to operation, so the task of creating such systems is very urgent. Aim of research Development of new structures and principles of operation of digital meters of parameters characterizing the efficiency of capacitive ignition systems of aircraft engines with semiconductor spark plugs. Research methods The issues of construction are considered and the developed hardware solutions for digital meters of parameters characterizing the efficiency of capacitive ignition systems of aircraft engines with semiconductor spark plugs are presented. The structures of the meters and timing diagrams of their operation are presented, and the features of using current and voltage sensors are discussed. Results The article presents the results of the development of measuring systems for parameters characterizing the efficiency of capacitive ignition systems of aircraft engines with semiconductor spark plugs — a meter for the criterion of the ignition ability of the ignition system as a function of the parameters of spark discharges in spark plugs and a universal meter for the duration of spark discharges, which allows measuring the duration of discharges of oscillatory and aperiodic types. The proposed technical solutions make it possible to improve the quality and completeness of assessing the efficiency of spark discharges in semiconductor spark plugs. The developed structures belong to the class of systems with «hard» operating logic and perform the necessary measuring operations with maximum speed.

Algorithms for calculating the reliability of an aircraft engine capacitive ignition system for different operating conditions

An algorithm is developed for calculating the reliability of a high-voltage two-channel capacitive ignition system of an aircraft engine under normal conditions and in case of damage of individual elements that ensure the durability of the ignition system under impacts not provided for by normal operation conditions. The assessment is carried out on the basis of reliability design schemes, taking into account the laws of discharge processes in semiconductor spark plugs. Expressions are obtained to determining the probability of fail safe operation of the ignition system. Keywords: two-channel capacitive ignition system, probability, fail safe operation, durability, discharge processes, design scheme, reliability. elaint@yandex.ru, yushkova-usatu@bk.ru, aliyakarimowa@yandex.ru

РЕЗОНАНСНЫЕ ЯВЛЕНИЯ В СИСТЕМАХ ЗАЖИГАНИЯ АВИАЦИОННЫХ ДВИГАТЕЛЕЙ

The relevance An analysis of scientific and technical literature in the field of development and research of aircraft engine ignition systems shows that the manifestations of resonant processes in nonlinear discharge circuits of capacitive ignition systems in the presence of two energy storage devices - a storage capacitor and an inductor coil have not been studied with the issuance of recommendations for matching the parameters of energy storage devices. This problem is of significant practical interest from the point of view of optimizing the parameters of the discharge circuits, increasing the energy efficiency and igniting ability of ignition systems. Aim of research Revealing the possibilities of increasing the efficiency of capacitive ignition systems based on the use of the manifestation of resonant processes in nonlinear discharge circuits containing two energy storage devices. Research methods Studies have been carried out involving a theoretical description of the processes during the discharge of the former charged capacitor to the R-L circuit, followed by experimental confirmation of the assumptions of the alleged states, described with the alleged resonance of occurrence in the discharge circuit using a similar falling current-voltage characteristic. Results The manifestations of resonant phenomena in a capacitive ignition system during the discharge of a capacitor on a non-linear circuit R-L are investigated. It is theoretically substantiated and experimentally proved that the dependences of the voltage in the spark discharge, the current and the energy of the discharges on the capacitance of the storage capacitor at a fixed inductance of the discharge circuit are uneven with inflection points corresponding to the equality of the inductive and capacitive resistances. It is shown that the energy efficiency of the discharge circuit can remain practically unchanged with a more than 1.5-fold decrease in the capacitance of the storage capacitor in the region of manifestation of resonant processes. The results obtained make it possible to coordinate the parameters of capacitive ignition systems, to determine the optimal values of the inductance of the discharge circuits for a given value of the capacitance of storage capacitors to ensure maximum energy efficiency and igniting capacity.

Effectiveness of pulse-plasma ignition systems with synchronization of processes in discharge circuits

The results of the development and modeling of pulse-plasma ignition systems (IS) of gas turbine engines with synchronization of processes in the main and auxiliary discharge circuits, which occupy an intermediate position between the pulsed capacitive and plasma IS, in which a long electric arc discharge is implemented, are presented. It is experimentally proven that the flammability of pulsed-plasma IS exceeds the igniting ability of capacitive IS of an oscillatory discharge with equal energies of storage capacitors. Keywords: pulse-plasma ignition system, aperiodic discharge, process synchronization, discharge current, spark plug voltage, flammability, starting characteristic of the igniter. texprom@yandex.ru

Assessing the Simulation of Capacitive Ignition Systems in Gas-Turbine Engines

Fast pulsed processes in the semiconductor spark plugs of capacitive ignition systems for gas-turbine engines are analyzed. The results may be used to assess existing models of ignition systems. The most stable dependences of the discharge parameters in the spark plugs on the discharge-circuit parameters are presented. The discharge-circuit parameters considered are its inductance; the capacitance and charging voltage of the storage capacitor; the electrode gap; the cable length; the material of the inductance core; and the type of spark discharge.

Regularities of fast-flowing pulsed discharge processes for assessing the adequacy of simulation results for capacitive ignition systems GTD

The results of the analysis of the laws of fast-flowing pulsed processes in semiconductor plugs of capacitive ignition systems of gas turbine engines (GTE), which can be a guideline for assessing the adequacy of the developed models of ignition systems, are presented. The most stable dependences of the energy parameters of discharges in semiconductor plugs on the parameters of the discharge circuits are presented — the capacitance and charge voltage of the storage capacitor, the inductance of the discharge circuit, the interelectrode gap, the cable length, the core material of the induction coil, type of spark discharge. Keywords capacitive ignition system, storage capacitor, semiconductor spark plug, spark discharge parameters texprom@yandex.ru

Instrumentation for modeling of discharge processes in ignition capacitive systems

In this article, developing a computer model allowing to obtain analytically the dependences of the discharge current i(t) and voltage in a spark discharge U(t) on the given discharge circuit parameters is carried out. A toolkit for evaluating the characteristics of capacitive ignition systems of various types at the stages of creating new circuit technical solutions and engineering has been developed. The obtained results allow to significantly reduce the time for evaluating the potential of ignition systems without carrying out sufficiently complex and labor-intensive experimental studies. The resulting dependences i(t) and U(t) allow to determine and calculate all the main parameters of spark discharges in plugs—energy, power and duration of discharges, as well as the maximum value of the discharge current.

Two-Channel Capacitive Ignition System with a Transistor Converter for Ground-Based Gas-Turbine Engines

A prototype of a two-channel capacitive ignition system for ground-based gas-turbine engines is developed. This system is based on a single-stage flyback transistor converter with a field-effect transistor controlled by an integrated timer. The timer operates in square-wave generator mode, with additional low-voltage voltage stabilization.

Oscillatory–Discharge Processes in Capacitive Ignition Systems with a Unipolar Pulse

The discharge processes in a capacitive ignition system with a unipolar pulse, which offers advantages as compared with ignition systems of oscillatory discharge, are investigated. It is noted that the received wisdom concerning the dynamics of development of a unipolar discharge pulse is rather conditional. It is shown that, for small values of inductance of discharge circuit, the discharge in the plug becomes oscillatory, with a pronounced oscillating component being superimposed onto the aperiodic component of the current. An experimental setup and a technique for investigating the oscillatory discharges when changing the parameters of the discharge circuit including the storage-capacitor capacitance and the inductances in the circuit of a shooting semiconductor plug and in the circuit of a high-voltage diode are described. The results of oscilloscope experimental studies and an analysis of results of measuring of the energy of spark discharges in the shooting semiconductor plug are presented depending on the parameters of the discharge circuit. The regularities of development of oscillatory discharges are laid out. It is shown that oscillatory discharges are generated not only under small inductances of the discharge circuit, but also when increasing the inductance in the case of connecting an additional inductance, the value of which is lower than the value of the main inductance, to the high-voltage diode circuit. It is proved that the energy efficiency of the capacitive ignition system of oscillatory discharge can exceed the efficiency of modern ignition systems with a unipolar pulse.

Factors Affecting the Life of Semiconductor Spark Igniters in Gas-Turbine Engines

The influence of the energy accumulated in the capacitive ignition system and the spark frequency on the life of semiconductor spark igniters in gas-turbine engines is investigated.

Characteristics of Plasma Ejection of Expulsion-Type Semiconductor Spark Plugs of Gas-Turbine Engines

Many variants are known of expulsion-type semiconductor plugs for capacitive ignition systems for gas-turbine engines, which differ in the design of discharge chambers. A distinctive feature of serial-produced expulsion-type plugs, which are manufactured by domestic industry, is the relative arrangement of semiconductor element and side electrode, at which the working surface of semiconductor is located not along the plug axis, but at an angle. The working surface of the side electrode is near the discharge-chamber base. There is no systematized information on research on discharge processes in the expulsion-type plugs in the technical literature. This work is dedicated to the study of interrelation between the energy parameters of spark discharges, space–time characteristics of plasma ejection from the discharge chambers of plugs, and plug-ignition effectiveness. The oscillography, together with plasma-ejection high-speed photographing methods, are used as research techniques. A serial-produced semiconductor plug and a specially developed model of expulsion-type plug with a window made of organic glass were chosen as the objects of research. The organic-glass window made it possible to photograph the process of plasma-discharge development within the discharge chamber. The oscillograms of discharge current and voltage drops in the plugs were recorded with a two-beam oscilloscope using a noninductive coaxial shunt and a resistive voltage divider. The parameters of plasma ejection were correlated with the plug-ignition effectiveness. The obtained results complement the general understandings of the regularities of development of plasma ejection from the discharge chambers of semiconductor plugs and confirm that the discharge parameters have an effect on the initial ignition speed from the standpoint of thermal and chain igniting mechanisms.