Glow Plug Research Articles

The initiation and development of combustion under cold idling conditions using a glow plug in diesel engines

Factors determining the success or failure of combustion initiation using a glow plug have been investigated through experimental work on a single cylinder, common rail diesel engine with a geometric compression ratio of 15.5, and a quiescent combustion bomb with optical access. A glow plug was required to avoid engine misfires when bulk gas temperature at the start of injection was less than 413 °C. The distance between the glow plug and the spray edge, the glow plug temperature, and the bulk gas temperature were important factors in meeting two requirements for successful ignition: a minimum local temperature of 413 °C and a minimum air/fuel vapour equivalence ratio of 0.15–0.35.

독립형 연료전지 시스템을 위한 가솔린 연료프로세스의 시동 및 운전

본 연구에서는 병참연료인 가솔린을 연료프로세서의 연료로 선택하여 광범위한 온도범위에서도 적용가능한 시동 및 제어 전략을 제시하였다. 가솔린 연료프로세서는 시동 초기 단계에서 연소 방식으로 상온상태의 자열개질기 촉매를 라이프온도까지 가열시킨다. 안정적인 가솔린-공기 혼합기체의 점화를 위하여 유동방향 기준 촉매 하단에 글로우 플러그를 설치하였다. 자열개질기가 촉매반응을 시작하면 가솔린 연료프로세서의 개질기는 정상상태까지 POX 모드, 부분 ATR 모드, 완전 ATR 모드 순으로 운전된다. 최종적으로 확립된 시동 및 제어 전략은 상온 및 저온 환경에서 가솔린 연료프로세서의 실제 실험을 통해 타당성을 확인하였다. 그 결과 가솔린 연료프로세서는 상온 및 저온에서 40분 이내에 정상상태에 도달하여 수소 37 ~ 42 vol.%(dry basis), 일산화탄소 0.3 vol.%의 개질가스를 생성할 수 있었다. This study introduces the system layout and control strategy necessary to start and operate a fuel processor in a wide range of temperatures where a gasoline was selected as the fuel of fuel processor considering logistic support of Korea Army. The autothermal reformig(ATR) catalyst is heated to light-off temperature by combustion method in the initial stage. In order to ignite the gasoline and air mixture stably, the glow plug is installed after ATR catalyst. When the catalyst is increased to light-off temperature, the reformer is operated from initiation to steady state conditions as follows: Partial oxidation(POX) mode, partial ATR mode, full ATR mode. Finally the start-up and control strategy is validated by the operational test of gasoline fuel processor at low and room temperature. As a result the gasoline fuel processor is able to start-up within 40 min and to produce the reformate gas which has 37 ~ 42 vol.%(dry basis) of <TEX>$H_2$</TEX> and 0.3 vol.% of CO.

Research on Performance and Temperature Control of Glow Plugs for PPCI Low Load Assist

Partial premixed compression ignition (PPCI) combustion is one of the most promising concepts to achieve combustion with high efficiency and low engine emissions. Glow plugs can be utilized to increase the combustion stability of PPCI combustion at idle or low loads, assisting the auto-ignition of gasoline or fuel with high octane number, which are major challenges remaining in PPCI combustion. The low load ignition assist application of glow plug is quite different from the traditional cold start assist. Other than simply heating the air in the cylinder, in the PPCI application the glow plug needs to heat the charge to specific temperatures at specific time, because the heating is vital to the ignition timing control in PPCI combustion. As a preliminary work of PPCI combustion low load assist application, in this paper infrared thermometer and some other devices were utilized to study the performance of representative glow plugs in open air. Based on the experiments, GPCU (glow plug control unit) was designed, open-loop and closed-loop temperature control algorithms were proposed. Further a lumped heat capacitance model of the glow plug was built based on system identification to study glow plug surface temperature behavior. It was found that PSG glow plug has excellent performance, maximum temperature of more than 1200°C was observed, 600 °C surface temperature was achieved in around 3 seconds. Open-loop temperature control was verified on GPCU; two glow plug temperature models were proposed, which can estimate the glow plug temperature for feedback control.

Precursor derived SiOC/MoSi&lt;sub&gt;2&lt;/sub&gt;-composites for diesel glow plugs: preparation and high temperature properties

Precursor derived SiOC/MoSi&lt;sub&gt;2&lt;/sub&gt;-composites for diesel glow plugs: preparation and high temperature properties

Puffing and micro-explosion of diesel–biodiesel–ethanol blends

The puffing and micro-explosion of a single burning droplet comprised of neat diesel, rapeseed methyl ester (RME); binary fuel mixtures of diesel–ethanol, diesel–RME, RME–ethanol; and ternary microemulsion of these fuel blends at various compositions have been studied using high speed backlight imaging method. Fuel droplet was suspended on the tip of a 130μm gauge thermocouple and it was ignited using a glow plug heater. Based on the temporal variation of droplet projected area, the characteristics of fuel droplets studied were classified into smooth burning, puffing and explosion. A ternary plot has been proposed to identify the mixture composition of the blends that can result in smooth burning, puffing and explosion. Micro-explosion phenomenon was observed in the ternary blends with ethanol percentages between 10% and 40%. Secondary droplets resulted from the puffing and explosion of suspended parent droplet were observed to undergo further explosion. The time scales associated with complete disintegration of secondary droplets are found to be comparable to the mixing and the chemical reaction time scales of sprays in diesel engines.

Hot surface ignition of n-hexane in air

An experimental investigation is conducted to analyze hot-surface ignition of n-hexane-air mixtures. The experimental setup, equipped with temperature diagnostics and schlieren imaging, utilizes a glow plug to initiate ignition in a flammable mixture. The hot-surface temperature at the point of ignition is measured for equivalence ratios ranging from 0.6 to 3 and chamber pressures varying from 25 to 100 kPa. The hot-surface temperature resulting in ignition is found to be weakly sensitive to equivalence ratio with a mean value of 980 K for mixtures with equivalence ratios between 0.75 and 3 at 100 kPa. Chamber pressure has a stronger influence with ignition temperature increasing to about 1140 K at 25 kPa. The experimental trends were reproduced in numerical simulations utilizing detailed chemistry of n-heptane as a surrogate for n-hexane given their similar ignition and flame propagation characteristics. The simulations further predict a two-stage ignition process resulting from an initial breakdown of the fuel with a small increase in temperature followed by a main ignition event accompanied by fuel depletion. Reaction rate analysis of the sequence of events leading to ignition conducted using a reduced order kinetic model suggests that the second-stage ignition event is caused primarily by the decomposition of hydrogen peroxide which occurs at temperatures above 900 K. The two-stage ignition process observed here is significantly different from that observed in previous studies due to the presence of convective and diffusive processes as well as the continuous increase in hot-surface temperature. These arguments are used to explain the insensitivity of ignition temperature to equivalence ratio, its decrease with increasing chamber pressure, and the location of the ignition kernel observed in experiments and simulations.

Critical firing and misfiring boundary in a spark ignition methanol engine during cold start based on single cycle fuel injection

The influence of the mass of methanol injected per cycle, ambient temperature, injection and ignition timing, preheating methods, and supplying additional liquefied petroleum gas (LPG) injection into the intake manifold on the critical firing and misfiring boundary of an electronically injection controlled spark ignition (SI) methanol engine during cold start were investigated experimentally based on a single cycle fuel injection with cycle-by-cycle control strategy. The critical firing and misfiring boundary was restricted by all parameters. For ambient temperatures below 16 °C, methanol engines must use auxiliary start-aids during cold start. Optimal control of the methanol injection and ignition timing can realize ideal next cycle firing combustion after injection. Resistance wire and glow plug preheating can provide critical firing down to ambient temperatures of 5 °C and 0 °C, respectively. Using an additional LPG injection into the intake manifold can provide critical firing down to an ambient temperature of −13 °C during cold start. As the ambient temperature decreases, the optimal angle difference between methanol injection timing and LPG injection timing for critical firing of a methanol engine increases rapidly during cold start.

Experimental Analysis on Glow Plug Hot Surface Ignition C. I. Engine using Methanol as Fuel with Additive

Experimental Analysis on Glow Plug Hot Surface Ignition C. I. Engine using Methanol as Fuel with Additive

PERFORMANCE AND EMISSION CHARACTERISTICS ON GLOW PLUG HOT SURFACE IGNITION C.I. ENGINE USING ETHANOL AS FUEL WITH ADDITIVE

The concept of using alcohol fuels as alternative to diesel fuel in diesel engine is recent one. The scarcity of transportation petroleum fuels due to the fast depletion of the petroleum deposits and frequent rise in their costs in the international market have spurred many efforts to find alternatives. Alcohols were quickly recognized as prime candidates to displace or replace high octane petroleum fuels. Innovative thinking led to find varies techniques by which alcohol can be used as fuel in diesel engine. Amongst the fuel alternative proposed, the most favourest ones are methanol and ethanol. The specific tendency of alcohols to ignite easily from a hot surface makes it suitable to ignite in a diesel engine by different methods. The advantage of this property of alcohols enables to design and construct a new type of engine called surface ignition engine. Methanol and ethanol are very susceptible to surface ignition, this method is very suitable for these fuels. The hot surfaces which, can be used in surface ignition engine are electrically heated glow plug with hot surface. Hence present research work carries the experimental investigation on glow plug hot surface ignition engine, by adding different additives with methanol and ethanol as fuels, with an objective to find the best one performance, emission and compression parameters.

Advanced Catalytic Igniters Technology for Small Compact Engine Applications

Development of technologies that allow small, high power density engines such as unmanned aerial vehicles (UAV), unmanned marine vehicles (UMV), and unmanned ground vehicles (UGV) to operate on single logistic fuel such as JP-8 is one of government goals. To advance this goal, a lightweight, compact, and retrofit capable ignition source is critical. Compared to standard spark igniters and noncatalytic glow plugs, the use of catalytic glow plugs will provide benefits of lower required compression ratio, improved igniter life, reduced electrical energy requirements, and overall reduction in system weight and size. Experimental testing demonstrated a significant increase in surface temperature (160+ °C) with impingement of a fuel spray compared to a conventional glow plug with engine testing demonstrating the use of catalyst allows stable engine operation at reduced power requirements. Computational analysis was performed to provide insight into the catalyst behavior. Analytical studies suggested increased stability due to both heat release due to exothermic catalytic reaction and production of reactive species. This technology would allow high power density engines to use heavy fuels, while potentially reducing electric power supply and engine complexity and weight, both of which would allow greater range and/or payload capacity. This paper discusses the feasibility of advanced igniters technology as an enabling component for the use of heavy fuels in small, high power density internal combustion engines. The paper presents and discusses analytical investigation, experimental test results, and durability testing data in an internal combustion engine environment.

Перспективы применения калильной свечи для реализации многократного запуска ракетных двигателей малой тяги на несамовоспламеняющемся двухкомпонентном топливе

Перспективы применения калильной свечи для реализации многократного запуска ракетных двигателей малой тяги на несамовоспламеняющемся двухкомпонентном топливе

Effect of pilot injection on engine noise in a single cylinder compression ignition engine

An experimental study was performed to investigate the effect of pilot injection on engine noise using a single cylinder combustion ignition engine. The engine rotary speed was fixed at 1200 RPM and a 10-mg quantity was injected at a pilot injection ratio of 1:9, 2:8, or 3:7. The engine performance parameters were calculated from the combustion pressure data acquired by a piezoelectric transducer (6057A80, Kistler), which was placed in the location of the glow plug. Engine noise was measured at a distance and height of 1 meter each from the engine for 9-10 seconds and analyzed using a commercial sound analysis program. By analyzing in-cylinder pressure and sound quality metrics, the following conclusions were obtained. The frequency analysis showed that the combustion noise was distributed at the frequency bands from 1100 Hz to 1900 Hz and from 2100 Hz to 2900 Hz. Pilot injections lowered the maximum rate of pressure increase, and the trend of the maximum pressure rise rate varied significantly according to injection pressure. The maximum pressure rise rate exhibited a linear relationship with sound level and loudness. Thus, the pilot injection strategy appeared to improve engine noise characteristics.

The simulation and production of glow plugs based on thermal modeling

In this work, we present the thermal behavior of a glow plug examined with thermal impedance modeling. The circuit model is based on the analogy of thermal and electrical domains and expresses the glow plug used in diesel engines to preheat the air-diesel fuel mixture. In this study, the circuit design, implementation, and simulation of a glow plug for diesel engines are illustrated. In order to verify this thermal model, 2 different glow plugs are produced. The test results of the glow plugs produced in this study show complete agreement with the simulation results. It is thought that this circuit-based model will provide fast and reliable simulations and will be benecial in the industry for addressing different glow plug needs.

Determination of Engine Speed by Using the Ceramic Glow Plug as a Sensor Element

Determination of Engine Speed by Using the Ceramic Glow Plug as a Sensor Element

IMPACT ANALYSIS OF INTERNAL CATALYST CONVERTER ON OPERATING PARAMETERS OF VW 1.9 TDI ENGINE

The largest amount of air pollutants is produced by the combustion of fossil fuels (coal, lignite, petroleum, natural gas, etc.). Such combustion releases huge amounts of greenhouse gases into the atmosphere (including carbon oxides (CO, CO2), sulphur oxides (SO2, SO3), nitrogen oxides (NO, NOx)) and dust, ashes and soot. Transportation is a significant share of the air pollution, mainly wheel-based transportation. The combustion process in diesel engine is very complex physico-chemically and varies in time. The process is accompanied by simultaneous exchange of heat and mass and chemical reactions. The development of internal combustion engines is made towards meeting of the increasingly stringent requirements for toxic exhaust emissions, reduction of fuel consumption, and preservation of Earth's natural resources. The problem to solve in modern diesel engines is the emission of toxic compounds. One way to reduce emissions is to use a catalytic converter positioned directly in the combustion chamber of an internal combustion engine. The aim of this analysis is assessment of toxic emissions of a diesel engine with an internal catalyst. Qualitative assessment of engine emissions was determined by comparing test results of an engine with ceramic-ally coated valves against one with just conventional valves (commercial valves without a ceramic coating). The study utilized a fourcylinder 1.9 TDI VW engine. It was expected that the use of glow plugs with an active coating would reduce the release of toxic compounds.

Three-dimensional numerical analysis of diesel combustion under cold ambient conditions

A lower compression ratio has been demanded for diesel engines in recent years to improve fuel consumption, exhaust emissions and maximum power recently. However, low compression ratio may have combustion instability issues under cold temperature condition, especially just after engine started. As the first step in this study, cold temperature combustion was investigated on the basis of an in-cylinder pressure analysis, and it was found that higher heat release around top dead center, which was mainly attributed to pilot injection, was a key factor in reducing engine speed fluctuation. Three-dimensional computational fluid dynamics simulations were conducted to obtain a better understanding of combustion under cold condition, particularly mixture formation near the glow plug. Specifically, for this purpose, a time-scale interaction combustion model was developed for simulating combustion phenomena. This model was based on a reasonable combustion mode, taking into account the characteristic time scale of chemical reactions and turbulence eddy breakup. In addition, the parameters of the ignition model and computational grids near the glow plug were improved for application to cold start conditions.

Glow-plug-assisted combustion of nitromethane sprays in a constant volume chamber

Experimental investigations on spray combustion of nitromethane in air within a constant volume chamber are presented. The sprays produced by a commercial gasoline injector, were ignited by using a pair of glow plugs, while the initial chamber pressure was varied from 1 bar to 7 bar. The nature of the combustion processes at various initial pressures was elucidated by measuring the pressure rise as well as using FTIR spectroscopy of the combustion products, and high speed photography. The maximum differential pressures reached during combustion were found to increase with chamber pressure up to 4 bar, and decrease thereafter while the ignition delays were found to be in the order of 10 ms for all pressures. The global equivalence ratio was found to vary from 0.43 at an initial pressure of 1 bar to 0.06 at an initial pressure of 7 bar, thus reducing the flame temperatures achieved within the chamber with increasing chamber pressures. The trends observed in the calculated heat release rates, cumulative heat released, and rate of heat loss from the chamber were found to provide key insights into the combustion process, which was concluded to be occurring through three distinct processes – turbulent premixed combustion, turbulent spray combustion, and turbulent film combustion. The effects of decreasing flame temperatures on the three processes were discussed in detail.

Operation of neat pine oil biofuel in a diesel engine by providing ignition assistance

The notion to provide ignition support for the effective operation of lower cetane fuels in a diesel engine has been ably adopted in the present study for the sole fuel operation of pine oil biofuel. Having noted that the lower cetane number and higher self-ignition temperature of pine oil biofuel would inhibit its direct use in a diesel engine, combined ignition support in the form of preheating the inlet air and installing a glow plug in the cylinder head has been provided to improve the auto-ignition of pine oil. While, an air preheater, installed in the inlet manifold of the engine, preheated the inlet air so as to provide ignition assistance partially, the incorporation of glow plug in the cylinder head imparted the further required ignition support appropriately. Subsequently, the operational feasibility of neat pine oil biofuel has been examined in a single cylinder diesel engine and the engine test results were analyzed. From the experimental investigation, though the engine performance and emissions such as CO (carbon monoxide) and smoke were noted to be better for pine oil with an inlet air temperature of 40°C, the engine suffered the setback of knocking due to delayed SOC (start of combustion). However, with the ignition support through glow plug and preheating of inlet air, the engine knocking was prevented and the normal operation of the engine was ensured. Categorically, at an inlet air temperature of 60°C, BTE (brake thermal efficiency) was found to be in par with diesel, while emissions such as CO and smoke were reduced by 13.2% and 16.8%, respectively, for neat pine oil biofuel at full load condition.

ANALYSIS OF CALCULATED CYCLES PARAMETERS IN CASE OF NATURAL GAS SUPPLY AND DIESEL ENGINE

The paper is dedicated to comparative analysis of cycles of engines supplied with natural gas having diesel compression ratio and quality power control with the basic diesel engine cycle. Two types of gas engines were investigated: with internal mixture formation and glow plug air-gas mixture ignition; with external mixture formation and air-gas mixture ignition with the help of pilot diesel fuel injection. Calculation results by external speed characteristics demonstrated that the gas engines were at least as good as the base diesel engines as regards to power and fuel efficiency. At the same time they have lower mechanical and thermal loads and considerably lower СО2 emissions.

COMPARATIVE ANALYSIS OF NATURAL GAS ENGINE PARAMETERS WITH QUALITY AND QUANTITY CONTROL

Parameters of natural gas engines were calculated with the aim to determine the optimal way of their working process organization. Analysis of calculations results demonstrated that quality power level control ensured the improvement of parameters of investigated engines. Calculations showed that compared with the diesel engine, the gas engine with quantity power level control, internal mixture formation and glow plug ignition of the gas-air mixture ensured the decrease of СО2 emissions by 26.8%, and the natural gas engine with quality power level control, external mixture formation and gas-air mixture ignition by a small pilot portion of fine atomized diesel fuel supplied by a Common Rail fuel system – by 25.5%. Therefore, one can choose one or another method of diesel engine conversion for operation on gas fuel considering available technical opportunities and with minimal expenses.