Experimental Investigation of the Heat Release Rate in a Sinusoidal Spark Ignition Engine

1989 ◽  
Author(s):  
Aaron George ◽  
Nigel Clark ◽  
James Smith ◽  
Jonathan Cox
Keyword(s):  
Experimental Investigation ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Spark Ignition ◽  
Spark Ignition Engine

Numerical Investigation of Fuel Property Effects on Mixed-Mode Combustion in a Spark-Ignition Engine

2019 ◽  
Author(s):  
Chao Xu ◽  
Pinaki Pal ◽  
Xiao Ren ◽  
Sibendu Som ◽  
Magnus Sjöberg ◽  
...  
Keyword(s):  
Heat Release ◽  
Flame Propagation ◽  
Heat Release Rate ◽  
Release Rate ◽  
Octane Number ◽  
Mixed Mode ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Chemical Effect ◽  
Auto Ignition

Abstract In the present study, mixed-mode combustion of an E30 fuel in a direct-injection spark-ignition engine is numerically investigated at a fuel-lean operating condition using multidimensional computational fluid dynamics (CFD). A fuel surrogate matching Research Octane Number (RON) and Motor Octane Number (MON) of E30 is first developed using neural network based non-linear regression model. To enable efficient 3D engine simulations, a 164-species skeletal reaction mechanism incorporating NOx chemistry is reduced from a detailed chemical kinetic model. A hybrid approach that incorporates the G-equation model for tracking turbulent flame front, and the multi-zone well-stirred reactor model for predicting auto-ignition in the end gas, is employed to account for turbulent combustion interactions in the engine cylinder. Predicted in-cylinder pressure and heat release rate traces agree well with experimental measurements. The proposed modelling approach also captures moderated cyclic variability. Two different types of combustion cycles, corresponding to purely deflagrative and mixed-mode combustion, are observed. In contrast to the purely deflagrative cycles, mixed-mode combustion cycles feature early flame propagation followed by end-gas auto-ignition, leading to two distinctive peaks in heat release rate traces. The positive correlation between mixed-mode combustion cycles and early flame propagation is well captured by simulations. With the validated numerical setup, effects of NOx chemistry on mixed-mode combustion predictions are investigated. NOx chemistry is found to promote auto-ignition through residual gas recirculation, while the deflagrative flame propagation phase remains largely unaffected. Local sensitivity analysis is then performed to understand effects of physical and chemical properties of the fuel, i.e., heat of evaporation (HoV) and laminar flame speed (SL). An increased HoV tends to suppress end-gas auto-ignition due to increased vaporization cooling, while the impact of HoV on flame propagation is insignificant. In contrast, an increased SL is found to significantly promote both flame propagation and auto-ignition. The promoting effect of SL on auto-ignition is not a direct chemical effect; it is rather caused by an advancement of the combustion phasing, which increases compression heating of the end gas.

Comparison Between Measured Radiance and a Radiation Model in a Spark-Ignition Engine

1990 ◽  
Vol 112 (3) ◽  
pp. 331-334 ◽  
Author(s):  
J. Yang ◽  
S. L. Plee ◽  
D. J. Remboski ◽  
J. K. Martin
Keyword(s):  
Heat Release ◽  
Release Rate ◽  
Maximum Rate ◽  
Spark Ignition ◽  
Rate Of Change ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Maximum Heat ◽  
Radiant Intensity ◽  
Maximum Heat Release

Measurements of the radiant emission in the near infrared have been obtained in a spark-ignition engine over a wide range of operating conditions. The system includes an in-cylinder optical sensor and associated detector. Prior work has shown correlations between the measured radiance and pressure quantities such as maximum cylinder pressure, crank angle of maximum pressure, and Indicated Mean Effective Pressure. Here are presented comparisons between the radiant intensity and a simplified model of the radiation emission, which demonstrate that the measured intensity is a function of the mass-burn fraction, mean burned-gas temperature, and the exposed combustion-chamber surface area. Further simplification leads to the conclusion that the time of the maximum rate of change of radiant intensity is the same as for the maximum heat-release rate, leading to the possibility of feedback control of spark timing. In addition, the magnitudes of the maximum rate of change of radiant emission and maximum heat-release rate have a linear relationship over a range of different operating conditions.

scholarly journals LARGE EDDY SIMULATION OF LEAN MIXED-MODE COMBUSTION ASSISTED BY PARTIAL FUEL STRATIFICATION IN A SPARK-IGNITION ENGINE

2021 ◽  
pp. 1-15
Author(s):  
Chao Xu ◽  
Sibendu Som ◽  
Magnus Sjoberg
Keyword(s):  
Large Eddy Simulation ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Mixed Mode ◽  
Spark Ignition ◽  
Pilot Injection ◽  
Eddy Simulation ◽  
Fuel Stratification ◽  
Large Eddy

Abstract Partial fuel stratification (PFS) is a promising fuel injection strategy to improve the stability of lean combustion by applying a small pilot injection near spark timing. Mixed-mode combustion, which makes use of end-gas autoignition following conventional deflagration-based combustion, can be further utilized to speed up the overall combustion. In this study, PFS assisted mixed-mode combustion in a lean-burn direct injection spark-ignition (DISI) engine is numerically investigated using multi-cycle large eddy simulation (LES). A previously developed hybrid G-equation/well-stirred reactor combustion model is extended to the PFS condition. The experimental spray morphology is employed to derive spray model parameters for the pilot injection. The LES based model is validated against experimental data and is further compared with the Reynolds-averaged Navier-Stokes (RANS) based model. Overall, both RANS and LES predict the mean pressure and heat release rate traces well, while LES outperforms RANS in capturing the CCV and the combustion phasing in the mass burned space. Liquid and vapor penetrations obtained from the simulations agree reasonably well with the experiment. Detailed flame structures predicted from the simulations reveal the transition from a sooting diffusion flame to a lean premixed flame, which is consistent with experimental findings. LES captures more wrinkled and stretched flames than RANS. Finally, the LES model is employed to investigate the impacts of fuel properties, including heat of vaporization (HoV) and laminar burning speed (SL). Combustion phasing is found more sensitive to SL than to HoV, with a larger fuel property sensitivity of the heat release rate from autoignition than that from deflagration. Moreover, the combustion phasing in the PFS-assisted operation is shown to be less sensitive to SL compared with the well-mixed operation.

scholarly journals Large Eddy Simulation of Lean Mixed-Mode Combustion Assisted by Partial Fuel Stratification in a Spark-Ignition Engine

2020 ◽  
Author(s):  
Chao Xu ◽  
Sibendu Som ◽  
Magnus Sjöberg
Keyword(s):  
Large Eddy Simulation ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Mixed Mode ◽  
Spark Ignition ◽  
Pilot Injection ◽  
Eddy Simulation ◽  
Fuel Stratification ◽  
Large Eddy

Abstract Lean operation is beneficial to spark-ignition engines due to the high thermal efficiency compared with conventional stoichiometric operation. Lean combustion can be significantly stabilized by the partial fuel stratification (PFS) strategy, in which a small amount of pilot injection is applied near the spark energizing timing in addition to main injections during intake. Furthermore, mixed-mode combustion, which makes use of end-gas autoignition following conventional deflagration-based combustion, can be further utilized to speed up the overall combustion. In this study, PFS-assisted mixed-mode combustion in a lean-burn direct injection spark-ignition (DISI) engine is numerically investigated using multi-cycle large eddy simulation (LES). To accurately represent the pilot injection characteristics, experimentally-derived spray morphology parameters are employed for spray modeling. A previously developed hybrid G-equation/well-stirred reactor model is extended to PFS conditions, to capture interactions of pilot injection, turbulent flame propagation and end-gas autoignition. The LES-based engine model is compared with Reynolds-averaged Navier-Stokes (RANS) based model, allowing an investigation of both mean and cycle-to-cycle variation (CCV) of combustion characteristics. Instantaneous spray and flame structures from simulations are compared with experiments. The LES-based model is finally leveraged to investigate impacts of fuel properties including heat of vaporization (HoV) and laminar flame speed (SL). It is shown that overall, the predicted mean pressure and heat release rate traces from both RANS and LES agree well with the experiment, while LES captures the CCV and the combustion phasing in the mass burned space much better than RANS. Predicted liquid fuel penetrations agree reasonably well with the experiment, both for RANS and LES. Detailed flame structures in the simulations also reveal the transition from a sooting flame to a lean premixed flame, which is consistent with experimental findings. LES is shown to capture more wrinkled and stretched flame fronts than RANS. Local sensitivity analysis further identifies the stronger combustion phasing sensitivity to SL compared with that to HoV, and the stronger sensitivity of autoignition heat release rate than deflagration. The results from this study demonstrate the high fidelity of the developed computational model based on LES, enabling future investigation of PFS-assisted mixed-mode combustion for different fuels and a wider range of operating conditions.

Development and Application of Advanced Combustion Modeling Tools for Heavy Duty Gaseous Fueled Industrial Spark Ignition Engines

2010 ◽  
Author(s):  
Harmit Juneja ◽  
Leon A. LaPointe ◽  
Francois Ntone ◽  
Edward J. Lyford-Pike ◽  
Xiao Qin
Keyword(s):  
Natural Gas ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Spark Ignition ◽  
Spark Ignition Engines ◽  
Heavy Duty ◽  
Modeling Tools ◽  
Combustion Modeling ◽  
Advanced Combustion

This paper covers the development and application of advanced combustion modeling tools to meet the stringent design objectives of heavy duty gaseous fueled industrial spark ignition engines. Extensive literature survey and validation work was conducted to identify the best available chemical mechanism to represent natural gas and its variations. Mechanism reduction using the Simulation Error Minimization (SEM) approach was undertaken to reduce the chemistry mechanism to a reasonable size for practical computational turn around times. Laminar flame speed (LFS) correlations were also developed using the identified chemistry mechanism. These fundamental elements were then integrated into a level set method (G-equation) based combustion model to predict heat release rate, exhaust gas composition, and the onset and intensity of autoignition (knock). The developed combustion modeling tools can handle lean or stoichiometric operation, presence of high levels of EGR, and variations in natural gas fuel composition. Detailed experimental data was available in the form of a spark timing sweep covering a non-knocking to a highly knocking operating condition for different fuel compositions. The intake flow modeling process was validated with available flow rig data at different valve lifts. Accurate modeling of the intake and compression process generates precise initial conditions for combustion modeling. Results are shown for conventional natural gas, natural gas containing 9% propane by mass, and natural gas containing 12% hydrogen mass fraction, at stoichiometric operating conditions. Excellent agreement with the measured data was observed in predicting heat release rate and the onset and intensity of knock for these different fuel compositions. The modeling tools developed in this study offer a robust methodology to design and optimize combustion systems for heavy duty gaseous fueled industrial spark ignition engines.

G0600-6-1 Experimental investigation of heat release rate in Bunsen flame tip affected by wall

2010 ◽  
Vol 2010.3 (0) ◽  
pp. 181-182
Author(s):  
Yusuke SUZUKI ◽  
Keisuke TAKEUCHI ◽  
Naoki HAYASHI ◽  
Hiroshi YAMASHITA ◽  
Kazuhiro YAMAMOTO
Keyword(s):  
Experimental Investigation ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Bunsen Flame
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