Maximum Heat Release Rate Research Articles

Effect of ignition heat source on design fire curve of polyethylene foam in a compartment fire

This study analyzed a design fire curve in accordance with of an ignition heat source in a compartment. For this purpose, a structure with a 1:3 reduced scale of the ISO 9705 room corner tester was fabricated using fireboard, and the time variant heat release rate was calculated according to the volume of a polyethylene foam combustible. To predict the design fire curve, the exponential equation proposed in a previous study was compared with the heat release rate measured in a fire experiment. The retard index, which is the main factor used to predicting the time required to reach the maximum heat release rate, decreased proportion to the ignition heat source. This relationship was presented in an empirical equation. Especially, the retard index decreased according to the size of the ignition heat source regardless of the volume of the polyethylene foam combustible. By establishing experimental data considering the type and change in the volume of combustibles, the findings of this study can be used to create improved design fire curve prediction models.

TESTING OF NATURAL INSULATION MATERIALS USING A CONICAL CALORIMETER

This paper examines three types of natural insulation materials, such as fiberboard, hemp and straw, from the point of view of fire safety. Cellulose-based materials allow a wide range of applications when used for insulation and weatherproofing of buildings, in particular floors, roofs, ceilings, attics, sound barriers, etc. The use of these materials is increasing in ecological constructions as well as for weatherproofing wood-based structures. In terms of fire safety requirements, the question is: Which insulating material is the safest in terms of fire propagation? The article focuses on natural products used as external insulation systems which are covered by a facade plaster. Each type of insulation is briefly described in terms of its composition, use, and production process. We describe the process of preparation of samples as well as the testing and measurement procedures. Three tests were carried out for each type of material. For a more objective evaluation, results were averaged. The results of the cone calorimeter were used to obtain data for comparison. The aim is to clarify the behavior of the natural insulating material with regard to the heat release rate, ignition time, burning duration, and maximum heat release rate. These are the essential parameters for comparison. The values were compared to determine the safest material from the point of view of fire safety.

Synergistic Effect of Pine Oil and Eucalyptus Oil on the Performance of a Compression Ignition Engine

ABSTRACT Many biofuels extracted from the trees can be directly used as a fuel without any major treatment processes. Among these biofuels the pine and eucalyptus oil have low viscosity and other properties similar to fossil diesel. In the present experimental study the feasibility of using the combination of both the fuels as a blend in diesel is investigated. The viscosity, boiling point and flash point of both the pine and eucalyptus oil were observed to be lower than conventional diesel. Also, the calorific values of these oil biofuels are comparable to diesel. In the present study, various blends of pine and eucalyptus oil viz., P10E10D80, P15E15D70, P5E5D90, P50E50, P20D80, and E20D80 blends were tested in a single-cylinder, four-stroke, direct injection diesel engine for the combustion, emissions and performance characteristics. The results show that at full load condition, the blend of P10E10D80 oil reduces EGT (exhaust gas temperature), HC (hydrocarbon). CO (carbon monoxide) and smoke emissions by 17%, 14.7%, 13%, 20.14%, respectively. The brake thermal efficiency and maximum heat release rate increase by 5.2% and 13%, respectively. However, the NOx (oxides of nitrogen) emission is higher 8.79% than that of diesel fuel at full load condition. The experimental work reveals that the blend of P10E10D80 possesses significantly improved fuel characteristics and can be directly used in diesel engine. Abbreviations: D100: Diesel 100% (Neat oil); P20+D80: Pine20 % +Diesel 80%; P10+E10+ D80: Pine10 %+ Eucalyptus10%+ Diesel 80%; P15+E15 +D70: Pine15 %+ Eucalyptus15%+Diesel 70%; P5+E5 +D90: Pine5%+ Eucalyptus5% +Diesel 90%; P50+EU50: Pine50 %+ Eucalyptus 50%; EU20+D80: Eucalyptus20%+ Diesel 80%; BTE: Brake thermal efficiency; BSEC: Brake specific energy consumption; HC: Hydrocarbon; CO: Carbon monoxide; NOx: Oxide of nitrogen; HRR: heat release rate; ID: Ignition delay; 0C/A: Degree crank angle; BMEP: Brake mean effective pressure; TDC: Top dead centre ; GC-MS: gas chromatography mass spectrometry; Surface tension: mN/m; Calorific value : (MJ/Kg); Flash point: Degree centigrade; density: Kg/m3; Kinematic viscosity: mm2/s; M.F: Molecular formula

Preparation and Flame Retardancy of Hydrotalcite/Montmorillonite Nanocomposite

Layered nanocomposite hydrotalcite/montmorillonite (LDH/MMT) was obtained though in-situ synthesis of nickel-magnesium-aluminum hydrotalcite (Ni-Mg-Al LDH) on the surface of montmorillonite nanosheets (MMTNS) by one-step hydrothermal method. X-ray diffractometer (XRD), Fourier Transform Infrared Spectrometer (FTIR), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) were used to characterize the composite material. The flame retardancy property of the composite was investigated by thermogravimetry (TG) and cone calorimeter (Cone). The results show that both the hydrotalcite and montmorillonite nanosheets have a lamellar structure; LDH/MMT composite has better thermal stability than that of hydrotalcite or montmorillonite alone, and the flame retardant effect of LDH/MMT on polystyrene (PS) is more obvious. The composite material can reduce the maximum heat release rate of polystyrene during combustion by 14.8%.

Characterization of pine and Eucalyptus oil and correlative evaluation of their performance as diesel blend in conventional diesel engine

ABSTRACT The present study envisages the use of diesel blended with plant based oils in conventional engine and their evaluation for engine performance and other emission parameters. Here, individual Pine (P20D80) and Eucalyptus oil (E20D80), and their same (1:1) proportion where ratio mixed (P10E10D80) as a 20% blend with the diesel was used. The selection of mentioned oils was made on the basis of their low viscosity and similarities to fossil diesel. The results revealed that when the engine was operated with P10E10D80, the brake thermal efficiency (5.5%) and lower fuel energy consumption was improved as compared to other blended fuels at full load. Also, the physicochemical characteristics such as viscosity, boiling point lower and calorific value of P10E10D80 were found to be comparable with conventional diesel. The cetane index of P10E10D80 was observed to be lower than E20D80 and conventional diesel, but higher than P20D80. The results revealed that P10E10D80 blend provide a maximum heat release rate of 71.94 J/CA at in-cylinder pressure of 79.63 bar and the ignition delay of the P10E10D80 blend was lower. Moreover, the EGT, HC, and CO smoke opacity emission of the P10E10D80 blend was lower as compared to diesel at full load. Interestingly, the atomization and evaporation rates of P10E10D80 were superior to other blends as well as conventional diesel. The results demonstrated reduction of 15.82%, 23%, 48%, and 26.79% in EGT, HC, CO, and smoke opacity, respectively, with the use of plant based oil blend with diesel. However, NOX emission was increased by 8.60% and observed a 13.50% higher heat release rate compare with blend and conventional diesel at full load. Moreover, an attempt to correlate the constituents of the oils with their performance has also been made.

Flame retardancy of rigid polyurethane foams containing thermoregulating microcapsules with phosphazene-based monomers

Thermoregulating microcapsules (MC) with flame-retardant properties were used to produce polyurethane (PU) foams. Thermogravimetric analyses of the microcapsules performed under atmospheric air and nitrogen confirmed that the hexa(methacryloylethylenedioxy) cyclotriphosphazene (PNC-HEMA) monomer raised the amount of residue after exposure to high temperature, proving the formation of a thermally stable char layer. Additionally, the flame-retardant properties of the microcapsules were analyzed by micro-combustion calorimetry (MCC), and the PU foams were tested by both MCC and cone calorimetry. The total heat release and maximum heat release rate were lower for microcapsules containing the flame-retardant PNC-HEMA. The composition of the microcapsules has been proved by MCC and TGA, where the release of the encapsulated phase change material (PCM) occurred at the expected temperature. However, in PU foams, the release of PCM is shifted to higher temperatures. Accordingly, these materials can be considered as an important alternative to commonly used microcapsules containing phase PCMs, where a lower flammability is required for their future application.Graphic abstract

Energy balance analysis, combustion characteristics, and particulate number concentration-NOx trade-off of a heavy-duty diesel engine fueled with various PODEn/diesel blends

Polyoxymethylene dimethyl ethers (PODEn) are promising diesel additives that have been widely evaluated and display many advantages for improving the combustion and emissions of diesel engines. There have been few investigations, however, that have performed an energy balance analysis of diesel/PODEn blends. Such an analysis would provide new insights into understanding the energy flow distribution and help further improve the energy conversion efficiency of diesel engines fueled with diesel/PODEn blends. For this reason, an energy balance analysis was conducted on a heavy-duty China VI diesel engine fueled with various diesel/PODEn blends (mass fractions of 10%, 20%, and 30%). In addition, combustion characteristics, as well as the particulate number concentration (PNC)-NOx trade-off relationship, were also examined. The results revealed that as the PODEn blending ratio increased, the effective work ratio (i.e., the brake thermal efficiency) gradually increased, while the exhaust loss ratio, cooling loss ratio, and incomplete combustion loss ratio decreased under each given operating condition. Therefore, fueling with diesel/PODEn blends caused the energy distribution to be superior and optimized compared to fueling with diesel fuel. Moreover, the PODEn addition reduced the peak in-cylinder pressure, mean in-cylinder temperature, and maximum heat release rate. Also, both the ignition delay and combustion duration were shortened, and the heat release process became both more concentrated and closer to the top dead center. This significantly improved the brake thermal efficiency, with the maximum increment reaching 3.29%. The trade-off between the NOx and PM emissions was significantly improved by blending PODEn during all operating conditions. In conclusion, diesel blending with PODEn effectively improved the energy conversion efficiency and combustion process of a test engine, resulting in a reduction of energy losses, especially under high load conditions.

Numerical study of cold-start performances of a medium compression ratio direct-injection twin-spark plug synchronous ignition engine fueled with methanol

The cold-start mixture preparation, combustion and emissions behaviors of a medium compression ratio direct-injection twin-spark plug synchronous ignition engine fueled with methanol were numerically simulated. Simulation results display that the methanol injection timing, ignition timing and the global equivalence ratio had an important influence on the concentration distribution of methanol-air mixture, the flow velocity, and the density of the flame surface during cold start. Ignition delay period reached the shortest at injection timing 70°CA BTDC. Ignition delay period for injection timing 130°CA BTDC and 50°CA BTDC increased 209% and 45.5% compared to injection timing 70°CA BTDC, respectively. Ignition delay period reached the shortest at ignition timing 21°CA BTDC. Ignition delay period of twin-spark plug was shorter than that of single-spark plug at the same equivalence ratio. There existed the maximum in-cylinder pressure, maximum heat release rate, maximum in-cylinder temperature, lowest unburned methanol and soot emissions, and highest NOX emissions at injection timing 70°CA BTDC. The maximum in-cylinder pressure, maximum heat release rate, and maximum in-cylinder temperature gradually increased with the advance of ignition timing. Injection timing 70°CA BTDC, ignition timing 21°CA BTDC, and equivalence ratio 0.9 could obtain the best cold start performance compromise using twin-spark plug ignition mode. At equivalence ratio 1.0, twin-spark plug ignition had better combustion performances, lower unburned methanol and soot emissions, and higher NOX emissions compared with single-spark plug ignition. Twin-spark plug synchronous ignition had more advantageous to cold starting ignition compared with single-spark plug ignition for a medium compression ratio direct-injection spark-ignition methanol engine.

Fire Hazard of Lithium-ion Battery Energy Storage Systems: 1. Module to Rack-scale Fire Tests

Lithium-ion batteries (LIB) are being increasingly deployed in energy storage systems (ESS) due to a high energy density. However, the inherent flammability of current LIBs presents a new challenge to fire protection system design. While bench-scale testing has focused on the hazard of a single battery, or small collection of batteries, the more complex burning behavior of a commercially design module (collection of batteries) or rack (collection of modules) is still largely unknown. In this study, a series of small- to large-scale free burn fire tests were conducted on ESS comprised of either iron phosphate (LFP) or lithium nickel oxide/lithium manganese oxide (LNO/LMO) batteries. Small-scale tests showed that a thermal runaway event could lead to a self-propagating fire for both the LFP and LNO/LMO batteries with a significantly greater heat release rate (HRR) generated from the LNO/LMO battery. Intermediate- and large-scale tests showed that the burning of a single module was sufficient to involve all other modules within the same ESS rack for both types of battery chemistries. The different burning behavior of the two battery chemistries was further demonstrated with the LNO/LMO battery generating a maximum HRR nearly three times that of the LFP battery. To better understand the hazard associated with these fires, a multi-point source model was used to analyze the radiative heat exposure to the environment. The end result is an experimentally validated data set that can be used to estimate the heat exposure to objects surrounding an ESS fire, such as ESS racks across an aisle space in a large deployment, or other nearby combustibles. These data also provide the basis for evaluating the effectiveness of sprinkler protection at reducing the fire hazard and protecting the surroundings.

Emission and performance estimation in hydrogen injection strategies on diesel engines

Recently, the increasing demand for energy requires the use of alternative fuels, especially in fossil fueled power systems. As a promising alternative fuel for next-generation diesel engines that utilize fossil fuel, hydrogen fuel is one step ahead due to its positive properties. In this study, the effects of hydrogen on the performance of a diesel engine have been numerically investigated with respect to different injection ratios and timings. The numerical results of the study for 25% load conditions on a single-cylinder, four-stroke diesel engine have been validated against experimental data taken from literature and good agreement has been observed for pressure results. Emission parameters such as NOx, CO and performance parameters such as cylinder temperature, pressure, power, thermal efficiency and IMEP are presented comparatively.The results of numerical analyses show that the maximum pressure, temperature and heat release rate are observed with injection ratio of H15 and early injection timing (20° CA BTDC). Besides that, engine power, thermal efficiency and IMEP are greatly improved with increasing injection ratio and early injection timing. Although combustion chamber performance parameters improve with rising the hydrogen injection ratio, higher NOx emissions have also been detected as a negative side effect. Furthermore, while early injection timing increases diesel engine performance, it also causes an increase in NOx emissions. Therefore, precise determination of injection timing together with the optimum amount of hydrogen has revealed that it brings crucial improvement in engine performance and emissions.

Activation Conditions of Sprinkler Head Considering Fire Growth Scenario

The aim of this study is to investigate the gas temperature and velocity during sprinkler activation considering the fire growth scenario based on the thermal response model of the sprinkler. The fire source is assumed to have time square fire growth scenarios with a maximum heat release rate of 3 MW. Eight types of standard and fast-response sprinkler heads with an operating temperature range of 65–105 ℃ and a response time index range of 25–171 m<sup>1/2</sup>s<sup>1/2</sup> were adopted. The temperature difference between the gas stream and the sensing element of the sprinkler head decreased as the fire growth slowed down, and the RTI value decreased. The overall gas temperature and velocity conditions predicted using the FDS model at sprinkler activation were in reasonable agreement with those of standard test conditions of the sprinkler head response. However, the sprinkler head could be activated at lower limits of gas temperature and velocity under the current test conditions for a slowly growing fire scenario.

An Experimental Study on the Fire Spread Rate and Separation Distance between Facing Stores in Passage-Type Traditional Markets

Real-scale fire experiments were conducted to understand the fire spread characteristics of the major combustibles handled in traditional markets, a space with high fire risk. The major combustibles were selected through field surveys administered at a number of traditional markets. Through real-scale fire experiments, the horizontal fire spread rate according to the maximum heat release rate of major combustibles was examined. In addition, the separation distance to prevent fire spread to the facing store by radiant heat transfer was examined. As a result of the experiments, it was confirmed that the arrangement method of the combustibles causes a large change in the maximum heat release rate, fire growth rate, and fire spread rate. The horizontal fire spread rate showed a linear proportional relationship with respect to the maximum heat release rate regardless of the type of combustibles, and a correlation to define the relationship was proposed. A correlation equation for predicting the separation distance that can prevent fire spread by radiant heat transfer was proposed, and the curve by the correlation equation was in good agreement with the experimental results. Through this study, it is expected that the correlation proposed to examine the horizontal fire spread rate and the separation distance of major combustibles in a traditional market can be usefully used in the design of fire protection systems to reduce fire damage in the traditional market.

Effects of the hydrogen and methane fractions in biosyngas on the stability of a small reciprocated internal combustion engine

A bio-syngas, produced from wood biomass gasification, is used with a small reciprocated spark ignition engine for higher thermal efficiency. In this experiment, as the knocking doesn’t occur even though the ignition timing is 70 deg-BTDC (before top dead center), the MBT, most-advanced for best torque ignition timing, couldn’t be determined. This phenomena, without knocking combustion, are reported by several researchers. In this report, the way to determine the ignition timing for the maximum efficiency is shown. With the cylinder pressure measurement, when the maximum heat release rate position is set near TDC, top dead center, the thermal efficiency shows the maximum and the stability shows the best in any hydrogen fraction or any methane fraction of the mixed fuel.Po.

Synthesis and characterization of carbon nanotubes from engine soot and its application as an additive in Schizochytrium biodiesel fuelled DICI engine

The present work investigated the synthesis of carbon nanotubes from engine soot particles by laser ablation vaporization method. The synthesized carbon nanotubes were characterized structurally by X-ray Diffraction, Scanning Electron Microscopy, Raman Spectroscopy and Thermogravimetry Analysis. Further, the effects of adding carbon nanotubes in to Schizochytrium methyl ester-diesel blended fuel (20% by volume Schizochytrium methyl ester + 80% diesel and 40% by volume Schizochytrium methyl ester + 60% diesel; symbolized by SCME 20 and SCME 40 respectively) were investigated on the performance, combustion and emission characteristics of direct injection diesel engine. The carbon nanotubes were mixed ultrasonically at two concentrations of 25 and 50 ppm in SCME 20 and SCME 40 individually. All blends were investigated under different engine loading conditions and their results reported that by adding carbon nanotubes at 25–50 ppm of SCME 20 increased the brake thermal efficiency by 2.5% and decreased the brake specific fuel consumption by 3.2% when compared to the neat SCME 20 blend. The maximum heat release rate and peak in-cylinder pressure were found increased by 5% and 4%, respectively. More specifically, the engine exhaust emissions such as UHC, CO, NOx and smoke found reduced by 14.28%, 23.07%, 5% and 21.52% respectively, at a concentrations of 50 ppm in SCME20 blends. The result showed that the concentrations of 50 ppm in SCME20 possess the optimum enhancement in the performance and emissions of the DICI engine.

Numerical investigation on the effect of oxygen in combustion characteristics and to extend low load operating range of a natural-gas HCCI engine

The effect of increasing oxygen on extending the low load operating range and combustion and emission characteristics of a natural-gas homogeneous charge compression ignition engine with pre-chamber is studied numerically. There are five oxygen percentage selected to investigate the influence of oxygen in homogeneous charge compression ignition combustion. The five selected Oxygen percentages are 21% (pure air), 40%, 60%, 80% and 100% (pure oxygen), which have 0.3 (pure air), 0.158, 0.105, 0.079 and 0.063 (pure oxygen) equivalence ratios, respectively. 60% oxygen is the optimum amount due to the earliest start of combustion and CA50 in all cases that directly affect the indicated mean effective pressure and efficiency. It has the maximum pressure, temperature, and heat release rate compared to the other oxygen percentages. Increasing oxygen up to 60%led to producing more OH radicals, while more increasing oxygen, causes a lack of H atoms from the decomposition of the CH bond in natural-gas caused to reducing OH concentration. Increasing oxygen makes the temperature distribution more uniform and shorts the combustion duration. It also leads to drop the temperature for the start of combustion. CO and UHC drop with excess oxygen, the maximums decreasing for CO and UHC are almost 100% and the minimums are 50.11% for CO and 80.4% for UHC occurring in 40% oxygen. Oxygen can extend the load range to the dilute regions, 40% oxygen would expand about 47.33% while by 60%, 80%, and 100% oxygen it would expand about 65%, 73.67%, and 79% respectively.

Analysis on the Fire Growth Rate Index Considering of Scale Factor, Volume Fraction, and Ignition Heat Source for Polyethylene Foam Pipe Insulation

The fire growth rate index (FIGRA), which is the ratio of the maximum value of the heat release rate (Qmax) and the time (tmax) to reach the maximum heat release rate, is a general method to evaluate a material in the fire-retardant performance in fire technology. The object of this study aims to predict FIGRA of the polyethylene foam pipe insulation in accordance with the scale factor (Sf), the volume fraction of the pipe insulation (VF) and the ignition heat source (Qig). The compartments made of fireboard have been mock-up with 1/3, 1/4, and 1/5 reduced scales of the compartment as specified in ISO 20632. The heat release rate data of the pipe insulation with the variation of Sf, VF, and Qig are measured from 33 experiments to correlate with FIGRA. Based on a critical analysis of the heat transfer phenomenon from previous research literature, the predictions of Qmax and tmax are presented. It is noticeable that the fire-retardant grade of the polyethylene foam pipe insulation could have Grade B, C, and D in accordance with the test conditions within ±15% deviation of the predicted FIGRA. In case of establishing the database of various types of insulation, the prediction models could apply to evaluate the fire-retardant performance.

Flammability Characteristics of Green Roofs

Assessing the fire risk of vegetated roofs includes the determination of their possible contribution to fire. Green roof components such as plants and growing media are organic materials and present a fuel that can catch and support the spread of fire. The flammability characteristics of these components were analyzed and compared to a typical roof covering. Growing media with 15% of organic matter were tested using cone calorimeter apparatus. The fuel load and heat release rate of the growing media were measured in both moist (30%) and dry conditions. It was observed that growing media in a moist condition do not present a fire risk, reaching a maximum heat release rate of 33 kW/m2. For dry substrates, a peak heat release rate of 95 kW/m2 was recorded in the first minute, which then rapidly decreased to 29 kW/m2 in the second minute. Compared to a typical bitumen roof membrane, the green roof showed a better fire performance. The literature data report more severe results for plant behavior, reaching peak heat release rates (HRRs) of 397 kW/m2 for dried and 176 kW/m2 for a green material. However, a rapid decrease in HRR to much lower values occurs in less than 2 min. The results also show that extensive and intensive types of green roofs present 22% and 95% of the additional fire load density when installed on a modified bitumen membrane, 19.7 and 85.8 MJ/m2, respectively.

Effects of injection timing on combustion performance and emissions in a diesel engine burning biodiesel blended with methanol

Currently, biodiesel has been received much attention from many researchers around the world due to its clean and renewable characteristics. In the present study, combustion and emissions characteristics have been studied on a modified four-cylinder, 4-stroke, water-cooled, direct injection compression internal engine equipped with a common rail fuel injection system fueled with methanol-biodiesel blends as well as pure biodiesel. The experiment was operated at a constant engine speed of 1800 rpm and injection timing from 2.5-22.5 ? crank angle before top dead center. With the injection timing advanced, peak in-cylinder pressure and maximum heat release rate increased while combustion start points were advanced. Ignition delay was shorten first and then prolonged while brake thermal efficiency was increased first and then decreased. With the injection timing in advance, NOx emissions increased, 1,3-butadiene and benzene emissions decreased while hydrocarbon and acetaldehyde emissions decreased first and then increased, and soot emissions increased first and then decreased.

Evaluation of Design Fire Curves for Single Combustibles in a Cinema Complex

An actual fire test was performed on single combustibles placed in a local cinema complex, and quantitative differences in the maximum heat release rate (HRR) and fire growth rate were investigated based on the design fire curve methods (i.e., the general and 2-stage methods). In terms of combustible use and fire load, a total of 12 combustibles were selected, classified into cinema lounge and movie theater. It was found that the maximum HRR and fire growth rate determined using the two-stage method were quantitatively different from those of the general method. The application of the two-stage method, which can be used to determine the fire growth rate of the initial fire stage more precisely, could be useful in accurately predicting the activation time of fire detectors and fire-extinguishing facilities, as well as the available safe egress time (ASET) and required safe egress time (RSET).

Sensitivity Analysis Applied to the Thermodynamic Diagnosis of Combustion in a Diesel Engine with DIAGNO-DIESEL® Software

At present, in order to mitigate the environmental impact of internal combustion machines and to increase their efficiency, it is necessary to carry out thermodynamic studies to predict their mechanical, thermal, and environmental behavior under different operational conditions. Within the thermodynamic modeling of thermal machines, it is necessary to carry out a process of characterization of the device under study. This article proposes a methodology for the characterization of 4JJ1 Isuzu Diesel engines applying combustion diagnosis, where the pressure signal in the combustion chamber is input, which is measured experimentally based on the angle of the crankshaft and how Exit the heat release curve. A motored procedure, in which the heat transfer process has been adjusted to the combustion chamber walls of the engine under study, has been performed. With this characterization, it has been verified that the change in 10% of the heat transfer adjustment coefficient in the chamber leads to a maximum change of 0.8% in the heat release rate through a sensitivity analysis of the developed model. The mass retained at the closing of the admission has a more pronounced effect, where a 10% change in this variable causes a 4.2% change in the heat release rate. A 10% change in the compression ratio has been observed, causing a maximum change of 6.1% in the heat release rate. Changes in the constants for piezoelectric transducer measurement, pressure level reference and crank angle measurement result in less than 5% change in maximum heat release rate values estimated by the diagnostic model.