scholarly journals Influence of high compression ratio and excess air ratio on performance and emissions of natural gas fuelled spark ignition engine

2018 ◽  
Vol 22 (5) ◽  
pp. 2013-2024 ◽  
Author(s):  
Mario Sremec ◽  
Mladen Bozic ◽  
Ante Vucetic ◽  
Darko Kozarac

Compressed natural gas is in automotive industry recognized as one of the ?cleanest? fossil fuels which can be used in internal combustion engines with a number of benefits. Since natural gas has much higher octane rating than gasoline it is expected that higher compression ratios can be used. The goal of the research is to determine the change of performance of spark ignited engine with the increase of compression ratio to values similar to compression ignited engine while keeping the exhaust emissions on the acceptable level and avoiding knock combustion. Measurements are performed at compression ratios 12, 16, and 18 at three different values of air excess ratio. Methane with known composition from a pressure cylinder is used instead of natural gas and the results are comprised of indicating results (in-cylinder and intake pressure in a crank angle space), emissions, temperatures, and mass-flows on various intake and exhaust positions. Analysis of results shows high influence of compression ratio and excess air ratio on combustion, performance, and exhaust gas emissions.

2019 ◽  
pp. 146808741985910 ◽  
Author(s):  
Guillermo Rubio-Gómez ◽  
Lis Corral-Gómez ◽  
David Rodriguez-Rosa ◽  
Fausto A Sánchez-Cruz ◽  
Simón Martínez-Martínez

In the last few years, increasing concern about the harmful effects of the use of fossil fuels in internal combustion engines has been observed. In addition, the limited availability of crude oil has driven the interest in alternative fuels, especially biofuels. In the context of spark ignition engines, bioalcohols are of great interest owing to their similarities and blend capacities with gasoline. Methanol and ethanol have been widely used, mainly due to their knocking resistance. Another alcohol of great interest is butanol, thanks to its potential of being produced as biofuel and its heat value closer to gasoline. In this study, a comparative study of gasoline–alcohol blend combustion, with up to 20% volume, with neat gasoline has been carried out. A single-cylinder, variable compression ratio, Cooperative Fuel Research-type spark ignition engine has been employed. The comparison is made in terms of fuel conversion efficiency and flame development angle. Relevant information related to the impact in the combustion process of the use of the three main alcohols used in blends with gasoline has been obtained.


2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Sachin Kumar Gupta ◽  
Mayank Mittal

Abstract Biogas, which is a renewable alternative fuel, has high antiknocking properties with the potential to substitute fossil fuels in internal combustion engines. In this study, performance characteristics of a spark-ignition (SI) engine operated under methane (baseline case) and biogas are compared at the compression ratio (CR) of 8.5:1. Subsequently, the effect of CR on operational limits, performance, combustion, and emission characteristics of the engine fueled with biogas is evaluated. A variable compression ratio, spark-ignition engine was operated at various CRs of 8.5:1, 10:1, 11:1, 13:1, and 15:1 over a wide range of operating loads at 1500 rpm. Results showed that the operating range of the engine at 8.5:1 CR reduced when biogas was utilized in the engine instead of methane. However, the operating range of the engine for biogas extended with an increase in CR—an increase from 9.6 N-m-16.5 N-m to 2.8 N-m-15.1 N-m was observed when CR was increased from 8.5:1 to 15:1. The brake thermal efficiency improved from 13.7% to 16.3%, and the coefficient of variation (COV) of indicated mean effective pressure (IMEP) reduced from 12.7% to 1.52% when CR was increased from 8.5:1 to 15:1 at 8 N-m load. The emission level of carbon dioxide was decreased with an increase in CR due to an improvement in the thermal efficiency and the combustion process.


2015 ◽  
Vol 773-774 ◽  
pp. 430-434
Author(s):  
Azizul Mokhtar ◽  
Nazrul Atan ◽  
Najib Rahman ◽  
Amir Khalid

Bio-additive is biodegradable and produces less air pollution thus significant for replacing the limited fossil fuels and reducing threats to the environment from exhaust emissions and global warming. Instead, the bio-additives can remarkably improve the fuel economy SI engine while operating on all kinds of fuel. Some of the bio-additive has the ability to reduce the total CO2 emission from internal petrol engine. This review paper focuses to determine a new approach in potential of bio-additives blends operating with bio-petrol on performance and emissions of spark ignition engine. It is shown that the variant in bio-additives blending ratio and engine operational condition are reduced engine-out emissions and increased efficiency. It seems that the bio-additives can increase the maximum cylinder combustion pressure, improve exhaust emissions and largely reduce the friction coefficient. The review concludes that the additives usage in bio-petrol is inseparable for the better engine performance and emission control and further research is needed to develop bio-petrol specific additives.


Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7037
Author(s):  
Donatas Kriaučiūnas ◽  
Tadas Žvirblis ◽  
Kristina Kilikevičienė ◽  
Artūras Kilikevičius ◽  
Jonas Matijošius ◽  
...  

Biogas has increasingly been used as an alternative to fossil fuels in the world due to a number of factors, including the availability of raw materials, extensive resources, relatively cheap production and sufficient energy efficiency in internal combustion engines. Tightening environmental and renewable energy requirements create excellent prospects for biogas (BG) as a fuel. A study was conducted on a 1.6-L spark ignition (SI) engine (HR16DE), testing simulated biogas with different methane and carbon dioxide contents (100CH4, 80CH4_20CO2, 60CH4_40CO2, and 50CH4_50CO2) as fuel. The rate of heat release (ROHR) was calculated for each fuel. Vibration acceleration time, sound pressure and spectrum characteristics were also analyzed. The results of the study revealed which vibration of the engine correlates with combustion intensity, which is directly related to the main measure of engine energy efficiency—break thermal efficiency (BTE). Increasing vibrations have a negative correlation with carbon monoxide (CO) and hydrocarbon (HC) emissions, but a positive correlation with nitrogen oxide (NOx) emissions. Sound pressure also relates to the combustion process, but, in contrast to vibration, had a negative correlation with BTE and NOx, and a positive correlation with emissions of incomplete combustion products (CO, HC).


2021 ◽  
pp. 1-20
Author(s):  
Jinlong Liu ◽  
Qiao Huang ◽  
Christopher Ulishney ◽  
Cosmin E. Dumitrescu

Abstract Machine learning (ML) models can accelerate the development of efficient internal combustion engines. This study assessed the feasibility of data-driven methods towards predicting the performance of a diesel engine modified to natural gas spark ignition, based on a limited number of experiments. As the best ML technique cannot be chosen a priori, the applicability of different ML algorithms for such an engine application was evaluated. Specifically, the performance of two widely used ML algorithms, the random forest (RF) and the artificial neural network (ANN), in forecasting engine responses related to in-cylinder combustion phenomena was compared. The results indicated that both algorithms with spark timing, mixture equivalence ratio, and engine speed as model inputs produced acceptable results with respect to predicting engine performance, combustion phasing, and engine-out emissions. Despite requiring more effort in hyperparameter optimization, the ANN model performed better than the RF model, especially for engine emissions, as evidenced by the larger R-squared, smaller root-mean-square errors, and more realistic predictions of the effects of key engine control variables on the engine performance. However, in applications where the combustion behavior knowledge is limited, it is recommended to use a RF model to quickly determine the appropriate number of model inputs. Consequently, using the RF model to define the model structure and then employing the ANN model to improve the model's predictive capability can help to rapidly build data-driven engine combustion models.


Author(s):  
Lorenzo Gasbarro ◽  
Jinlong Liu ◽  
Christopher Ulishney ◽  
Cosmin E. Dumitrescu ◽  
Luca Ambrogi ◽  
...  

Abstract Investigations using laboratory test benches are the most common way to find the technological solutions that will increase the efficiency of internal combustion engines and curtail their emissions. In addition, the collected experimental data are used by the CFD community to develop engine models that reduce the time-to-market. This paper describes the steps made to increase the reliability of engine experiments performed in a heavy-duty natural-gas spark-ignition engine test-cell such as the design of the control and data acquisition system based on Modbus TCP communication protocol. Specifically, new sensors and a new dynamometer controller were installed. The operation of the improved test bench was investigated at several operating conditions, with data obtained at both high- and low-sampling rates. The results indicated a stable test bench operation.


2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Mingzhang Pan ◽  
Haiqiao Wei ◽  
Dengquan Feng

Exhaust gas recirculation (EGR) has gained prominence as a significant method to control port fuel injection engine knock caused by high compression ratio and high intake pressure (IP). In this paper, the effect of EGR on knock intensity was investigated under various conditions which included different compression ratios (9:1, 10:1, 11:1), IPs (1.0 bar, 1.2 bar, 1.4 bar) and intake temperatures (ITs, 20 °C, 40 °C, 60 °C). The torque output being a crucial variant was also considered. The results showed that EGR effectively reduced the maximum amplitude of pressure oscillations (MAPO) and knock intensity factor (KI20). The effect of EGR on knock resistance was more significant at higher compression ratio, IP, and IT. The output torque of the engine reached a peak value with a suitable EGR ratio which also controlled the intensity of knock under different conditions.


2014 ◽  
Vol 18 (1) ◽  
pp. 39-52
Author(s):  
Bijan Yadollahi ◽  
Masoud Boroomand

In this study, a numerical model has been developed in AVL FIRE software to perform investigation of Direct Natural Gas Injection into the cylinder of Spark Ignition Internal Combustion Engines. In this regard two main parts have been taken into consideration, aiming to convert an MPFI gasoline engine to direct injection NG engine. In the first part of study multi-dimensional numerical simulation of transient injection process, mixing and flow field have been performed via three different validation cases in order to assure the numerical model validity of results. Adaption of such a modeling was found to be a challenging task because of required computational effort and numerical instabilities. In all cases present results were found to have excellent agreement with experimental and numerical results from literature. In the second part, using the moving mesh capability the validated model has been applied to methane Injection into the cylinder of a Direct Injection engine. Five different piston head shapes along with two injector types have been taken into consideration in investigations. A centrally mounted injector location has been adapted to all cases. The effects of injection parameters, combustion chamber geometry, injector type and engine RPM have been studied on mixing of air-fuel inside cylinder. Based on the results, suitable geometrical configuration for a NG DI Engine has been discussed.


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