Heat Release Parameters Research Articles

The influence of Animal Fat Methyl Ester (AME) on diesel engine work parameters

This paper presents the analysis of the base energy parameters and composition of exhaust gases for one-cylinder test diesel engine SB 3.1. fuelled by standard diesel fuel (DF) and Animal Fat Methyl Ester (AME). Animal Fat Methyl Ester (AME) is the result of using waste pork fat. A lot of publications analyze the use of fish fat methyl ester (CFME) and chicken fat methyl esters (CFME) but in Polish conditions we have a lot of pork fat waste. All of measurement was carried out on the some engine speed – 1600 rpm (speed of maximum engine torque) and various engine loads. Some of the analysed parameters were read directly from the laboratory measurement systems (e.g. fuel consumption) and the rest of them had been calculated (e.g. total efficiency of engine). Before the engine tests, the basic physical parameters of the used fuels were determined in the fuel laboratory: dynamic viscosity as a function of fuel temperature, distillation curve, combustion heat and calorific value. The calorific value of the used AMF fuel is 37,4 MJ/kg (42,6 MJ/kg for DF). As a result of the AME fuel viscosity analysis, it was found that in the fuel system of the internal combustion engine this fuel should be heated to the temperature 65°C. Hourly AMF fuel consumption is about 9% higher than for standard diesel fuel (DF). The overall efficiency of the engine, taking into account the calorific value of the fuel and the fuel heating energy, is lower by about 7% for the AMF-powered engine than for DF fuelled engine. In the case of an AMF-powered engine, a higher NOx concentration and a lower smoke opacity than for a DF-powered engine are obtained. For more accurate cause and effect analysis, the indicator diagrams and the rate of heat release in the cylinder of the combustion engine fuelled by the tested fuels (AMF and DF) were measured, which includes the second article: The influence of Animals Fat Methyl Ester (AME) on the indicator diagrams and heat release parameters in diesel engine cylinder.

The influence of non-cooled exhaust gas recirculation on the indicator diagrams and heat release parameters in diesel engine cylinder

This paper presents the results of the diesel engine research on the indicator and heat realized diagrams for VW 1.9 TDI working in 2 modes: with standard, non-cooled EGR system, and without this system. All of measurement was carried out on the some engine speed – 2000 rpm (speed of maximum engine torque) and various engine load. Some of the analyzed parameters were read directly from the measurement systems (e.g. indicator diagrams) or engine controller (e.g. start of injection) and the rest of them had to be calculated. The calculation of rate of heat release (dQ/dα) was based on the well-known mathematical model. When the exhaust gas recirculation valve is open, the maximum of combustion pressure and rate of maximum kinetic heat release (dQk/dα)max are smaller than when the valve is closed. These facts are connected with the shorter self-combustion delay for engine working with EGR. But this is also associated with reduction of the rate of maximum diffusion heat release (dQd/dα)max, which means that more particulates (PM) are excreted into the atmosphere. This fact explains e.g. significantly higher smog of exhaust gases for diesel engine which works with EGR system. The analysis results show that exhaust gas recirculation system slightly deteriorates the energetic parameters of VW 1.9 TDI engine, but, at the same time, significantly reduces the level of toxic nitrogen oxides in exhaust gases

Effects of hydrogen enrichment on combustion characteristics of a CI engine

In this study a comprehensive investigation of combustion (cylinder pressure, rate of pressure rise, ignition delay) and heat release (rate of heat release, cumulative heat release and center of heat release) parameters of a four cylinder, turbocharged, common rail compression ignition engine running with hydrogen addition was carried out. Hydrogen was send into intake manifold by using a mixing chamber. Flow rates of hydrogen were 20 lpm and 40 lpm for achieving constant speed of 1750 rpm at 50 Nm, 75 Nm and 100 Nm engine loads (EL). Results showed that maximum cylinder pressures (CPs), rate of pressure rises (ROPRs) and ignition delays (IDs) raised, rate of heat releases (ROHRs) decreased and combustion durations (CDs) extended with hydrogen addition.

Development of a reduced chemical mechanism targeted for a 5-component gasoline surrogate: A case study on the heat release nature in a GCI engine

Gasoline Compression Ignition (GCI) is a promising engine operating mode that can reduce maximum pressure rise rate (MPRR) without knock tendency and better control the combustion phasing compared to the Homogeneous Charge Compression Ignition (HCCI) by using a late direct-injection (DI). In this study, a 107-species reduced mechanism and a 207-species skeletal mechanism were developed using the Computer Assisted Reduction Mechanism (CARM) and validated under engine conditions for a newly developed 5-component surrogate for a Haltermann 437 certification gasoline (AKI=93). Then, 3D computational fluid dynamics (CFD) simulations with an optimized grid size determined by a grid convergence study were performed with the 107-species reduced mechanism and the 5-component certification gasoline surrogate. Two experimental boosted GCI cases with similar, moderate MPRR and heat release parameters, but different second DI timings (−52° aTDC and −5° aTDC), were validated and analyzed. For the −52° aTDC DI case, the combustion can be interpreted as a partially sequential auto-ignition due to the competition between the charge cooling effect and the equivalence ratio (ϕ)-sensitive effect of the stratified mixture, which is responsible for mitigating the MPRR. For the −5° aTDC DI case, the combustion can be decoupled into a partially sequential auto-ignition and a subsequent non-premixed combustion by the DI fuel near top dead center in the compression stroke. The MPRR is relaxed through the slow, mixing-limited combustion between the injected fuel and the premixed mixture.

Implementation of two color method to investigate late cycle soot oxidation process in a CI engine under low load conditions

Soot emissions from diesel engines are an important concern in meeting emissions regulations. Soot emissions are the result of two competing processes: soot formation and soot oxidation. Mechanisms of soot formation are discussed extensively in the literature. Equivalence ratio at lift-off length along with residence time and gas temperature play an important role for soot formation in a diffusion flame. Mixing capability and bulk gas temperature are the most important parameters that influence the in-cylinder soot oxidation process. Normally, research studies of soot formation-oxidation processes have been developed under controlled and not completely representative conditions of engine operation in the field. Therefore, the main objective of this work was to develop a simplified methodology to evaluate in-cylinder soot oxidation under ‘real’ engine conditions. In particular the impact of mixing process and bulk gas temperature on late cycle soot oxidation was evaluated. The experimental measurements were made in a production light-duty diesel engine varying those parameters that have been demonstrated in the literature as the most relevant in soot formation – oxidation processes; injection pressure, ambient density and intake air temperature. To measure soot, two color method was applied by means of an optoelectronic pyrometer. To evaluate the mixing capability a specific “tracer” Apparent Combustion Time (ACT−1) based on the experimental heat release and injection parameters was defined. The relationship between both parameters was used to explain the soot oxidation process.

THE RESEARCH OF SIMPLIFICATION OF 1.9 TDI DIESEL ENGINE HEAT RELEASE PARAMETERS DETERMINATION / 1,9 TDI DYZELINIO VARIKLIO ŠILUMOS IŠSISKYRIMO PARAMETRŲ NUSTATYMO SUPAPRASTINIMO TYRIMAS

The investigation of modified methodology of Audi 1.9 TDI 1Z diesel engine heat release parameters’ determination is represented in the article. In this research the AVL BOOST BURN and IMPULS software was used to treat data and to simulate engine work process. The reverse task of indicated pressure determination from heat release data was solved here. T. Bulaty and W. Glanzman methodology was modified for purpose to simplify the determination of heat release parameters. The maximal cylinder pressure, which requires additional expensive equipment, was changed into the objective indicator – exhaust gas temperature. This modification allowed to simplify the experimental engine tests and also gave simulation results in an error range up to 2% of main engine operating parameters. The study results are assessed as an important point for the simplification of engine test under field conditions. Straipsnyje pateikta dyzelinio Audi variklio 1,9 TDI 1Z šilumos išsiskyrimo parametrų nustatymo metodikos ir jos modifikavimo tyrimas. Šio tyrimo procese atilikto eksperimento duomenims apdoroti ir darbo procesui modeliuoti panaudoti AVL BOOST BURN ir IMPULS programiniai paketai. Tyrime buvo sprendžiamas atvirkščias indikatorinio slėgio nustatymo iš šilumos charakteristikos duomenų uždavinys. Siekiant supaprastinti šilumos išsiskyrimo parametrų nustatymą, panaudota modifikuota T. Bulaty ir W. Glanzman metodika. Maksimalaus slėgio cilindre parametras, kurio nustatymas reikalauja papildomos brangios įrangos, buvo pakeistas objektyviu išmetamųjų dujų temperatūros parametru. Šis modifikavimas leidžia supaprastinti eksperimentinius tyrimus bei leido atlikti pagrindinių variklio darbo parametrų modeliavimą neviršijant 2 % paklaidų ribos. Tyrimo rezultatas vertinamas itin svarbiu variklių bandymų lauko sąlygomis supaprastinimo atžvilgiu.

Approximate Model of Chemical Reaction Kinetics for Detonation Processes in Mixture Of CH4 with Air

An approximate two-stage kinetic model of the chemical reaction in methane/oxygen mixtures containing water and inert diluents is developed. The model includes one differential equation for the calculation of the molar mass of the gas after the induction period and algebraic formulas for the calculation of the heat release, internal energy, and thermodynamic parameters of the mixture. Based on this model, 2D numerical simulations of irregular multifront detonation wave in a stoichiometric methane/air mixture is performed. The calculated results of the detonation structure and cell width correspond very well to the available experimental data.

A novel flame-retardant acrylonitrile-butadiene-styrene system based on aluminum isobutylphosphinate and red phosphorus: Flame retardance, thermal degradation and pyrolysis behavior

Aluminum isobutylphosphinate (APBu) and its synergistic system with red phosphorus (APBu/RP) were used to flame-retard ABS. With the addition of APBu to ABS, the flame retardance of the material was greatly improved, that LOI value was as high as 29.8%, and a UL-94 V-0 rating was obtained; moreover, heat release parameters obtained from cone calorimetry decreased. However, the smoke release of the material during combustion increased. When RP was added to ABS-APBu system, flame-retardant synergism was gained, and it was helpful to reduce the smoke release of the material. The decomposition behaviors of materials were studied by thermogravimetric analysis (TG), and it was found that the residues of materials at 700 °C increased with the addition of APBu or APBu/RP. The flame-retardant mechanisms of APBu and APBu/RP were analyzed by Fourier transform infrared spectrum (FTIR), scanning electron microscopy (SEM) and pyrolysis-gas chromatograph/mass spectrometer (Py-GC/MS). Results suggested that the addition of RP to ABS-APBu further enhanced the flame retardation of APBu both in the gaseous phase and condensed phase, leading to a high synergistic effect.

On laminar flame speed correlations for H2/CO combustion in premixed spark ignition engines

The stringent regulations on the reduction of both pollutant emissions and dependence from crude oil have increased the interest toward alternative energy resources. Transport and energy production sectors are strongly involved in the pollutions net environmental balance and, at the same time, their primary energy requirements are significant. In this scenario, several efforts are carried out to identify new solutions. In the last two decades, in the automotive industry, the use of several alternative fuels for internal combustion engine applications has been investigated. Specifically, this work focuses on syngas and its use in spark ignition (SI) engines. First, a comprehensive analysis of the syngas combustion process has been carried out and accurate laminar flame speed correlations are proposed to characterize the fuel oxidation. Then, these correlations have been implemented in a CFD model to simulate a CFR engine combustion process. Different H2/CO–air mixtures (fuel molar ratio ranging from 50:50 to 100:0 of H2:CO) at different engine operating conditions (compression ratio from 6:1 to 10:1 and fuel equivalence ratio from 0.6 to 0.8) have been considered and the results have been compared with available experimental data. A good agreement has been observed in all conditions, in terms of pressure trace, heat release and other parameters that are useful to characterize the combustion process in SI engines, i.e. burn duration, ignition lag and rapid burn angle.

Comparative analysis of performance, emission and combustion parameters of diesel engine fuelled with ethyl ester of fish oil and its diesel blends

The thirst for fuel is steadily increasing as technology continues to open new areas of exploration. At the same time, the indiscriminate extraction of fossil fuels also may result in extinction of petroleum deposits in foreseeable future. Along with this, pollutant emission from diesel engines causes major impacts on ecological systems. In order to overcome the above problems associated with the use of petroleum derived fuels, a suitable source of biodiesel should be used to replace conventional diesel fuel. Hence, in this work, feasibility of using biodiesel prepared from fish oil was investigated. Various properties such as viscosity, density, calorific value, flash point and cetane value of biodiesel and biodiesel–diesel blends of different proportions were investigated. Later, experimental tests were carried out to evaluate the performance, emission and combustion characteristics of a single cylinder, constant speed, direct injection diesel engine using biodiesel–diesel blends, under variable load conditions. It was found that there was a reduction in NOx, HC and CO emission along with a marginal increase of CO2 and smoke emissions with the increase in biodiesel proportion in the fuel. The brake thermal efficiency was found to be higher compared to diesel for the entire load. An analysis of the cylinder pressure rise, heat release, and other combustion parameters such as peak pressure, rate of pressure rise, combustion duration and ignition delay was carried out. The ignition delay, maximum heat release rate and combustion duration were lower for biodiesel–diesel blends compared to diesel. Ultimately, fish oil can indeed become the appropriate source for biodiesel, with environmental benefits.

Modelling the effect of injection pressure on heat release parameters and nitrogen oxides in direct injection diesel engines

Investigation and modelling the effect of injection pressure on heat release parameters and engine-out nitrogen oxides are the main aim of this study. A zero-dimensional and multi-zone cylinder model was developed for estimation of the effect of injection pressure rise on performance parameters of diesel engine. Double-Wiebe rate of heat release global model was used to describe fuel combustion. extended Zeldovich mechanism and partial equilibrium approach were used for modelling the formation of nitrogen oxides. Single cylinder, high pressure direct injection, electronically controlled, research engine bench was used for model calibration. 1000 and 1200 bars of fuel injection pressure were investigated while injection advance, injected fuel quantity and engine speed kept constant. The ignition delay of injected fuel reduced 0.4 crank angle with 1200 bars of injection pressure and similar effect observed in premixed combustion phase duration which reduced 0.2 crank angle. Rate of heat release of premixed combustion phase increased 1.75 % with 1200 bar injection pressure. Multi-zone cylinder model showed good agreement with experimental in-cylinder pressure data. Also it was seen that the NOx formation model greatly predicted the engine-out NOx emissions for both of the operation modes.

Combustion characteristics of cellulosic loose fibres

SUMMARYThe aim of this paper is to study the combustion characteristics of loose fibrous cellulosic compounds through cone calorimeter measurements. The challenge in studying loose fibrous materials by cone calorimeter in a reproducible manner is met by optimizing various process parameters such as sample weight, heat flux and grid type. The method is validated using cotton fibres and fabrics with a range of flame retardant properties. Good correlations are obtained between the flame retardant content of samples and the heat release parameters for both the fibres and the fabrics. In addition, fibres from specific cotton cultivars showed statistically significant differences in heat release characteristics. This shows that valuable data concerning the combustion behaviour and the corresponding kinetics of loose fibrous compounds can be successfully gathered using a cone calorimeter. Thus, such data can be exploited to well define future fibre breeding programmes or fibre modification research. Copyright © 2012 John Wiley & Sons, Ltd.

Research on the Combustibility of PI Needle Punched Nonwovens by Cone Calorimeter

This paper demonstrates the combustibility of PI needle punched nonwovens by Cone Calorimeter. Ignition parameter, heat release parameters, smoke and toxicity parameters and mass loss parameters of the fabric were obtained from it. It was found that ignition time is 38 s; the peak of heat release rate is 65 kW/m2; total heat release is 7 MJ/m2; smoke release rate is 1.5 L/s; smoke factor is 1.3 MW/m2 and mass lose rate is 73.3%. Therefore the results show that PI needle punched nonwovens has excellent fire-resistance performance.

Statistical analysis of the cyclic variations of heat release parameters in HCCI combustion of methanol and gasoline

Combustion instability and cyclic variations lead to the requirement of closed loop control for use of homogeneous charge compression ignition (HCCI) engine technology for automotive applications. The closed loop control of HCCI combustion requires robust combustion timing parameters with a systematic and detailed study of its variations vis-à-vis engine operating conditions. An experimental study is conducted to provide insight into cyclic variations of HCCI combustion phasing for two fuels (gasoline and methanol) using statistical techniques. In this study, cycle-to-cycle variations of heat release parameters such as Maximum Rate of Heat Release (ROHRmax), 10% Mass Burn Fraction (MBF), 50% MBF, 90% MBF and Indicated Mean Effective Pressure (IMEP) of HCCI combustion engine fueled with methanol and gasoline were investigated using a modified two-cylinder, four-stroke engine. The experiments were conducted with different engine operating conditions at constant intake air temperature (140°C) and different air–fuel ratios at constant engine speed (1500rpm). To evaluate the cycle-to-cycle variations of combustion parameters at different test conditions, coefficient of variation (COV) and standard deviation of parameters were used. The results showed that CA50 (crank angle position of 50% MBF) is a robust parameter for the closed loop control of HCCI combustion.

Textile heat release properties measured by microscale combustion calorimetry: experimental repeatability

SUMMARYIn this research, we evaluated the repeatability of microscale combustion calorimetry (MCC) measurement of heat release properties for different textile fabrics including polypropylene, cotton, polyester, Kevlar, acrylic, nylon, silk, and the cotton treated with an organophosphorus flame retardant. The repeatability investigation was mostly based on the measurement of peak heat release rate (PHRR) and heat release capacity (HRC), the two most important heat release parameters measured by MCC. We found that PHRR and HRC of most textile fibers had coefficient of variance (CV) lower than and in the vicinity of 3.0. The CVs were influenced by both the standard deviation (SD) of measurements and by the values of these measurements. The use of an aerobic pyrolysis environment (80/20 nitrogen/oxygen) for MCC experiments did not affect the repeatability of measurement. We also evaluated the shift of the oxygen analyzer as a result of long‐term usage, and found that PHRR and HRC of cotton decreased between−4.0 and−3.9, respectively, after an 11‐month period, indicating that the shift of the oxygen analyzer is limited. Experimental factors influencing the MCC repeatability were also discussed. Copyright © 2011 John Wiley & Sons, Ltd.

Modelling of the thermal cycle of a gas engine using AVL FIRE Software

Paper presents results of modelling gas engine thermal cycle using AVL FIRE and KIVA 3V software. There are described three combustion models used in software. KIVA and FIRE software are used in Institute of Internal Combustion Engines and Control Engineering for analysis of thermal cycle of IC engines. FIRE software gives many possibilities with many combustion models. All used combustion models are dependent on turbulence of flow field before ignition. Comparison of modelling results of thermal cycle of IC engine is presented in paper. Pressure, temperature, heat release and turbulence parameters variations in function of crank angle as well as spatial distribution of above mentioned quantities at selected crank angles were determined.

Comparative Performance, Emission, and Combustion Characteristics of Rice-Bran Oil and Its Biodiesel in a Transportation Diesel Engine

The methyl esters of vegetable oils known as biodiesel are becoming increasingly popular because of their low environmental impact and potential as a green alternative fuel for diesel engines. Methyl ester of rice-bran oil (RBOME) is prepared through the process of transesterification. In the present investigation, experiments have been carried out to examine the performance, emission, and combustion characteristics of a direct-injection transportation diesel engine running with diesel, 20% blend of rice-bran oil (RBO), and 20% blend of RBOME with mineral diesel. A four-stroke, four-cylinder, direct-injection transportation diesel engine (MDI 3000) was instrumented for the measurement of the engine performance, emissions, in-cylinder pressure-crank angle history, rate of pressure rise, and other important combustion parameters such as instantaneous heat release rate, cumulative heat release rate, mass fraction burned, etc. A careful analysis of the performance, emissions, combustion, and heat release parameters has been carried out. HC, CO, and smoke emissions for RBO and RBOME blends were lower than mineral diesel while NOx emissions were almost similar and brake specific fuel consumption (BSFC) was slightly higher than mineral diesel. Combustion characteristics were quite similar for the three fuels.

A comprehensive experimental investigation of combustion and heat release characteristics of a biodiesel (hazelnut kernel oil methyl ester) fueled direct injection compression ignition engine

In the present study, hazelnut ( Corylus avellana L.) kernel oil was transesterified with methanol using potassium hydroxide as catalyst to obtain biodiesel and a comprehensive experimental investigation of combustion (cylinder gas pressure, rate of pressure rise, ignition delay) and heat release (rate of heat release, cumulative heat release, combustion duration and center of heat release) parameters of a direct injection compression ignition engine running with biodiesel and its blends with diesel fuel was carried out. Experiment parameters included the percentage of biodiesel in the blend, engine load, injection timing, injection pressure, and compression ratio. Results showed that hazelnut kernel oil methyl ester and its blends with diesel fuel can be used in the engine without any modification and undesirable combustion and heat release characteristics were not observed. The modifications such as increasing of injection timing, compression ratio, and injection pressure provided significant improvement in combustion and heat release characteristics.

Characterization of the Combustion Process of Flame Resistant Thermal Protective Textiles in the Presence of Oily Contaminants: Effects of Contamination and Decontamination

This paper reports two experimental studies wherein the combustion process of flame resistant (FR) thermal protective textiles is characterized in terms of thermal decomposition and heat release parameters before and after contamination and in terms of heat release parameters after contamination and decontamination. Aramid and FR cotton/nylon decomposed at higher and aramid/FR viscose at lower temperature in the presence of oil. Oil interferes with thermally induced interactions between aramid and FR viscose, altering the thermal decomposition rates and formation of char, and thereby increasing the effectiveness of the flame retardant present in the viscose. It is apparent that oily contaminants present in FR fabrics affect the initiation of the thermal degradation and formation of char. All contaminated FR fabrics showed significantly higher peak heat release rate (PHRR), total heat release (THR) and effective heat of combustion (EHC) compared to uncontaminated ones. Oily specimens laundered with no detergent or prewash product had higher PHRR, THR and EHC compared to other treatments regardless of the fabric type or number of contamination/decontamination cycles. Heat release increased with increased number of contamination/decontamination cycles for most laundry treatments for all FR fabrics. FR cotton/nylon had the highest and aramid had the lowest PHRR and THR whether specimens were uncontaminated, contaminated or decontaminated. In this study heat release from FR fabrics increased with increased oily contamination.

Identification of one-zone heat release parameters for SI engine

Heat release analysis is used for predicting the gross heat release characteristic from the pressure data inside the cylinder. In present work, simulation of one-zone heat release model, which involves large number of physically important parameters, is done in Matlab/Simulink environment. The objective here is to find out that how many of these parameters can be reliably determined using in-cylinder pressure measurements. Levenberg-Marquardt optimisation method is used to minimise a least-square objective function for determining the parameters. The smaller value of the objective function is not enough to validate the quality of parameters estimated; hence, their reliability is determined by studying the logarithmic P-V diagram. A methodology is also proposed to find out the parameters, which cannot be identified reliably. The present approach helps in identifying one-zone heat release parameters systematically and prevents the use of arbitrary values of parameters.