Cycle-by-Cycle Exhaust Temperature Monitoring for Detection of Misfiring and Combustion Instability in Reciprocating Engines

2007 ◽  
Author(s):  
David P. Gardiner ◽  
William D. Allan ◽  
Marc LaViolette ◽  
Michael F. Bardon
Keyword(s):  
Electromagnetic Interference ◽  
Combustion Instability ◽  
Pressure Sensors ◽  
Combustion Stability ◽  
Cylinder Pressure ◽  
Combustion Analysis ◽  
Exhaust Temperature ◽  
Reciprocating Engines ◽  
Temperature Signal ◽  
Combustion Monitoring

This paper describes a means of achieving cycle-by-cycle combustion monitoring of reciprocating engines without the use of cylinder pressure sensors. This approach is intended primarily for engines that are not equipped with indicator passages (that would facilitate the installation of cylinder pressure sensors) but are (or can be) equipped with fittings for individual cylinder exhaust thermocouples. The monitoring system uses rugged exhaust temperature probes and advanced signal processing and analysis to detect cycle-by-cycle variations in exhaust temperatures and correlates these with conventional combustion analysis parameters. The system is particularly useful for detecting the deteriorations in combustion stability that precede misfiring as well as individual misfire events if they occur. Engine test results are presented showing the correlation between the exhaust temperature signal and parameters based upon cylinder pressure measurements. The ability to detect low level combustion instability and isolated, individual misfires has been demonstrated on a 95 liter V12 industrial natural gas engine. It as also been shown that successful acquisition of high fidelity exhaust temperature signals for the combustion analysis can be achieved in the presence of the high levels of electromagnetic interference typical of a power generation facility.

scholarly journals Real-Time Monitoring of Combustion Instability in a Homogeneous Charge Compression Ignition (HCCI) Engine Using Cycle-by-Cycle Exhaust Temperature Measurements

2012 ◽  
Author(s):  
David P. Gardiner ◽  
W. Stuart Neill ◽  
Wallace L. Chippior
Keyword(s):  
Real Time ◽  
Fuel Injection ◽  
Combustion Instability ◽  
Temperature Measurements ◽  
Cylinder Pressure ◽  
Hcci Engine ◽  
Exhaust Temperature ◽  
Indicated Mean Effective Pressure ◽  
Test Engine ◽  
Reference Measurements

This paper describes an experimental study concerning the feasibility of monitoring the combustion instability levels of an HCCI engine based upon cycle-by-cycle exhaust temperature measurements. The test engine was a single cylinder, four-stroke, variable compression ratio Cooperative Fuel Research (CFR) engine coupled to an eddy current dynamometer. A rugged exhaust temperature sensor equipped with special signal processing circuitry was installed near the engine exhaust port. Reference measurements were provided by a laboratory grade, water-cooled cylinder pressure transducer. The cylinder pressure measurements were used to calculate the Coefficient of Variation of Indicated Mean Effective Pressure (COV of IMEP) for each operating condition tested. Experiments with the HCCI engine confirmed that cycle-by-cycle variations in exhaust temperature were present, and were of sufficient magnitude to be captured for processing as high fidelity signal waveforms. There was a good correlation between the variability of the exhaust temperature signal and the COV of IMEP throughout the operating range that was evaluated. The correlation was particularly strong at the low levels of COV of IMEP (2–3%), where production engines would typically operate. A real-time combustion instability signal was obtained from cycle-by-cycle exhaust temperature measurements, and used to provide feedback to the fuel injection control system. Closed loop operation of the HCCI engine was achieved in which the engine was operated as lean as possible while maintaining the COV level at or near 2.5%.

Spark Advance Real-Time Optimization Based on Combustion Analysis

2010 ◽  
Author(s):  
Enrico Corti ◽  
Claudio Forte
Keyword(s):  
Real Time ◽  
Pressure Sensors ◽  
Heat Losses ◽  
Test Time ◽  
Cylinder Pressure ◽  
Combustion Analysis ◽  
Mean Values ◽  
Control Setting ◽  
Cycle Variation ◽  
Novel Approach

Future emission regulations could force manufacturers to install in-cylinder pressure sensors on production engines. The availability of such a signal opens a new scenario in terms of combustion control: many settings that previously were optimized off-line, can now be monitored and calibrated in realtime. One of the most effective factors influencing performance and efficiency is the combustion phasing: in gasoline engines Electronic Control Units (ECU) manage the Spark Advance (SA) in order to set the optimal combustion phase. SA optimal values are usually determined by means of calibration procedures carried out on the test bench by changing the ignition angle while monitoring Brake and Indicated Mean Effective Pressure (BMEP, IMEP) and Brake Specific Fuel Consumption (BSFC). The optimization process relates BMEP, IMEP and BSFC mean values with the control setting (SA). However, the effect of SA on combustion is not deterministic, due to the cycle-to-cycle variation: the analysis of mean values requires many engine cycles to be significant of the performance obtained with the given control setting. This paper presents a novel approach to SA optimization, with the objective of improving the performance analysis robustness, while reducing the test time. The approach can be either used in the calibration phase or in on-board applications, if the in-cylinder pressure signal is available: this would allow maintaining the optimization active throughout the entire engine life. The methodology is based on the observation that, for a given running condition, IMEP can be considered a function of a single combustion parameter, represented by the 50% Mass Fraction Burned (50%MFB). Due to cycle-to-cycle variation, many different MFB50 and IMEP values are obtained during a steady state test carried out with constant SA, but these values are related by means of a unique relationship. The distribution on the plane IMEP-MFB50 forms a parabola, therefore the optimization could be carried out by choosing SA values maintaining the scatter around the vertex. Unfortunately the distribution shape is slightly influenced by heat losses (i.e., by SA): this effect must be taken into account in order to avoid over-advanced calibrations. SA is then controlled by means of a PID (Proportional Integer Derivative) controller, fed by an error that is defined based on the previous considerations: a contribution is related to the MFB50-IMEP distribution, and a second contribution is related to the net Cumulative Heat Release (CHRNET)-IMEP distribution. The latter is able to take into account for heat losses. Firstly, the methodology has been tested on in-cylinder pressure data, collected from different SI engines; then, it has been implemented in real-time, by means of a programmable combustion analyzer: the system performs a cycle-to-cycle combustion analysis, evaluating the combustion parameters necessary to calculate the target SA, which is then actuated by the ECU. The approach proved to be efficient, reducing the number of engine cycles necessary for the calibration to less than 1000 per operating condition.

scholarly journals Experimental Study on Dynamic Combustion Characteristics in Swirl-Stabilized Combustors

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1609
Author(s):  
Donghyun Hwang ◽  
Kyubok Ahn
Keyword(s):  
Experimental Study ◽  
Heat Release ◽  
Dynamic Pressure ◽  
Combustion Instability ◽  
Flame Structure ◽  
Pressure Sensors ◽  
Necessary Condition ◽  
Rayleigh Criterion ◽  
Pressure Oscillations ◽  
Geometric Conditions

An experimental study was performed to investigate the combustion instability characteristics of swirl-stabilized combustors. A premixed gas composed of ethylene and air was burned under various flow and geometric conditions. Experiments were conducted by changing the inlet mean velocity, equivalence ratio, swirler vane angle, and combustor length. Two dynamic pressure sensors, a hot-wire anemometer, and a photomultiplier tube were installed to detect the pressure oscillations, velocity perturbations, and heat release fluctuations in the inlet and combustion chambers, respectively. An ICCD camera was used to capture the time-averaged flame structure. The objective was to understand the relationship between combustion instability and the Rayleigh criterion/the flame structure. When combustion instability occurred, the pressure oscillations were in-phase with the heat release oscillations. Even if the Rayleigh criterion between the pressure and heat release oscillations was satisfied, stable combustion with low pressure fluctuations was possible. This was explained by analyzing the dynamic flow and combustion data. The root-mean-square value of the heat release fluctuations was observed to predict the combustion instability region better than that of the inlet velocity fluctuations. The bifurcation of the flame structure was a necessary condition for combustion instability in this combustor. The results shed new insight into combustion instability in swirl-stabilized combustors.

Extension of the Combustion Stability Range in Dry Low NOx Lean Premixed Gas Turbine Combustor Using a Fuel Rich Annular Pilot Burner

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
L. Rosentsvit ◽  
Y. Levy ◽  
V. Erenburg ◽  
V. Sherbaum ◽  
V. Ovcharenko ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Combustion Zone ◽  
Combustion Instability ◽  
Experimental Results ◽  
Nox Emission ◽  
Combustion Stability ◽  
Stability Range ◽  
Numerical Effort ◽  
Lean Premixed ◽  
Pilot Burner

The present work is concerned with improving combustion stability in lean premixed (LP) gas turbine combustors by injecting free radicals into the combustion zone. The work is a joint experimental and numerical effort aimed at investigating the feasibility of incorporating a circumferential pilot combustor, which operates under rich conditions and directs its radicals enriched exhaust gases into the main combustion zone as the means for stabilization. The investigation includes the development of a chemical reactors network (CRN) model that is based on perfectly stirred reactors modules and on preliminary CFD analysis as well as on testing the method on an experimental model under laboratory conditions. The study is based on the hypothesis that under lean combustion conditions, combustion instability is linked to local extinctions of the flame and consequently, there is a direct correlation between the limiting conditions affecting combustion instability and the lean blowout (LBO) limit of the flame. The experimental results demonstrated the potential reduction of the combustion chamber's LBO limit while maintaining overall NOx emission concentration values within the typical range of low NOx burners and its delicate dependence on the equivalence ratio of the ring pilot flame. A similar result was revealed through the developed CHEMKIN-PRO CRN model that was applied to find the LBO limits of the combined pilot burner and main combustor system, while monitoring the associated emissions. Hence, both the CRN model, and the experimental results, indicate that the radicals enriched ring jet is effective at stabilizing the LP flame, while keeping the NOx emission level within the characteristic range of low NOx combustors.

A NOx Reduction Project for a GT11 Type Gas Turbine

2005 ◽  
Author(s):  
Lars O. Nord ◽  
David R. Schoemaker ◽  
Helmer G. Andersen
Keyword(s):  
Power Plant ◽  
Distribution System ◽  
Gas Turbines ◽  
Nox Reduction ◽  
Measurement Data ◽  
Combustion Stability ◽  
Study Phase ◽  
Nox Emissions ◽  
Ambient Conditions ◽  
Exhaust Temperature

A study was initiated to investigate the possibility of significantly reducing the NOx emissions at a power plant utilizing, among other manufacturers, ALSTOM GT11 type gas turbines. This study is limited to one of the GT11 type gas turbines on the site. After the initial study phase, the project moved on to a mechanical implementation stage, followed by thorough testing and tuning. The NOx emissions were to be reduced at all ambient conditions, but particularly at cold conditions (below 0°C) where a NOx reduction of more than 70% was the goal. The geographical location of the power plant means cold ambient conditions for a large part of the year. The mechanical modifications included the addition of Helmholtz damper capacity with an approximately 30% increase in volume for passive thermo-acoustic instability control, significant piping changes to the fuel distribution system in order to change the burner configuration, and installation of manual valves for throttling of the fuel gas to individual burners. Subsequent to the mechanical modifications, significant time was spent on testing and tuning of the unit to achieve the wanted NOx emissions throughout a major part of the load range. The tuning was, in addition to the main focus of the NOx reduction, also focused on exhaust temperature spread, combustion stability, CO emissions, as well as other parameters. The measurement data was acquired through a combination of existing unit instrumentation and specific instrumentation added to aid in the tuning effort. The existing instrumentation readings were polled from the control system. The majority of the added instrumentation was acquired via the FieldPoint system from National Instruments. The ALSTOM AMODIS plant-monitoring system was used for acquisition and analysis of all the data from the various sources. The project was, in the end, a success with low NOx emissions at part load and full load. As a final stage of the project, the CO emissions were also optimized resulting in a nice compromise between the important parameters monitored, namely NOx emissions, CO emissions, combustion stability, and exhaust temperature distribution.

scholarly journals Cylinder pressure sensors for smart combustion control

2019 ◽  
Vol 8 (1) ◽  
pp. 75-85 ◽  
Author(s):  
Dennis Vollberg ◽  
Dennis Wachter ◽  
Thomas Kuberczyk ◽  
Günter Schultes
Keyword(s):  
Thin Films ◽  
Test Bench ◽  
Copper Wire ◽  
Combustion Process ◽  
Pressure Sensors ◽  
Gauge Factor ◽  
Full Detail ◽  
Relative Pressure ◽  
Cylinder Pressure ◽  
Combustion Control

Abstract. Different sensor concepts for time-resolved cylinder pressure monitoring of combustion engines are realized and evaluated in this paper. We distinguish a non-intrusive form of measurement outside the cylinder, performed by means of a force compression rod from intrusive, real in-cylinder measurement by means of pressure membrane sensors being exposed to the hot combustion process. The force compression rod has the shape of a sine wave with thinner zones equipped with highly sensitive foil strain gauges that experience a relatively moderate temperature level of 120 ∘C. The sensor rod delivers a relative pressure value that may be influenced by neighbour cylinders due to mechanical coupling. For the intrusive sensor type, two different materials for the membrane-type sensor element were simulated and tested, one based on the ceramic zirconia and the other based on stainless steel. Due to the higher thermal conductivity of steel, the element experiences only 200 ∘C while the zirconia element reaches 300 ∘C. Metallic chromium thin films with high strain sensitivity (gauge factor of 15) and high-temperature capability were deposited on the membranes and subsequently structured to a Wheatstone bridge. The pressure evolution can be measured with both types in full detail, comparable to the signals of test bench cylinder pressure sensors. For the preferential steel-based sensor type, a reliable laser-welded electrical connection between the thin films on the membrane and a copper wire was developed. The in-cylinder pressure sensors were tested both on a diesel test bench and on a gas-fired engine. On the latter, an endurance test with 20 million cycles was passed. Reliable cylinder pressure sensors with a minimum of internal components are thus provided. The signals will be processed inside the sensor housing to provide analysis and aggregated data, i.e. mass fraction burned (MFB50) and other parameters as an output to allow for smart combustion control.

Cylinder-Pressure-Based Engine Control Using Pressure-Ratio-Management and Low-Cost Non-Intrusive Cylinder Pressure Sensors

2000 ◽  
Author(s):  
Mark C. Sellnau ◽  
Frederic A. Matekunas ◽  
Paul A. Battiston ◽  
Chen-Fang Chang ◽  
David R. Lancaster
Keyword(s):  
Low Cost ◽  
Pressure Ratio ◽  
Pressure Sensors ◽  
Engine Control ◽  
Cylinder Pressure

scholarly journals Tailoring Charge Reactivity Using In-Cylinder Generated Reformate for Gasoline Compression Ignition Strategies

2016 ◽  
Author(s):  
Isaac W. Ekoto ◽  
Benjamin M. Wolk ◽  
William F. Northrop ◽  
Nils Hansen ◽  
Kai Moshammer
Keyword(s):  
Performance Metrics ◽  
Engine Performance ◽  
Combustion Stability ◽  
Gas Temperature ◽  
Exhaust Temperature ◽  
Start Of Injection ◽  
Main Period ◽  
Piston Crevice ◽  
Ignition Characteristics ◽  
Negative Valve Overlap

In-cylinder reforming of injected fuel during an auxiliary negative valve overlap (NVO) period can be used to optimize main-cycle combustion phasing for low-load Low-Temperature Gasoline Combustion, where highly dilute mixtures can lead to poor combustion stability. The objective of this work is to examine the effects of reformate composition on main-cycle engine performance for a research gasoline. A custom alternate-fire sequence with nine pre-conditioning cycles was used to generate a common exhaust temperature and composition boundary condition for a cycle-of-interest. Performance metrics such as main-period combustion stability and total cycle efficiency were collected for these custom cycles. The NVO-produced reformate stream was also separately collected using a dump valve apparatus and characterized in detail using both gas chromatography and photoionization mass spectroscopy. To facilitate gas sample analysis, sampling experiments were conducted using a five-component gasoline surrogate (iso-octane, n-heptane, ethanol, 1-hexene, and toluene) that matched the molecular composition, 50% boiling point, and ignition characteristics of the research gasoline. For the gasoline, it was found that the most advanced NVO start-of-injection (SOI) led to the most advanced main-cycle 10% burn angle. The effect was more pronounced as the fraction of total fuel injected in the NVO period increased. With the most retarded NVO SOI, shorter residence times and piston spray impingement limited the opportunity for injected fuel decomposition. For the gasoline surrogate, the most advanced NVO SOI had reduced reactivity relative to more intermediate NVO SOI, which was attributed to rapid in-cylinder mixing that led to a large amount of fuel quench in the piston crevice. For all NVO periods, combustion phasing advanced as the main-period fueling decreased. Slower kinetics for leaner mixtures were offset by a combination of increased bulk-gas temperature from higher charge specific heat ratios and increased fuel reactivity due to higher charge reformate fractions.

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