scholarly journals Performance of direct injected propane and gasoline in a high stroke-to-bore ratio SI engine: Pathways to diesel efficiency parity with ultra low soot

2021 ◽  
pp. 146808742110069
Author(s):  
D Splitter ◽  
V Boronat ◽  
FDF Chuahy ◽  
J Storey
Keyword(s):  
Particle Size ◽  
Compression Ratio ◽  
Thermal Efficiency ◽  
High Efficiency ◽  
Spark Ignition ◽  
Liquid Films ◽  
Spark Ignition Engine ◽  
Gasoline Direct Injection ◽  
Combustion Stability ◽  
Engine Operation

This work explores pathways to achieve diesel-like, high-efficiency combustion with stoichiometric 3-way catalyst compatible combustion in a single-cylinder spark ignition (SI) research engine. A unique high stroke-to-bore engine design (1.5:1) with cooled exhaust gas recirculation (EGR) and high compression ratio ( rc) was used to improve engine efficiency by up to 30% compared with a production turbocharged gasoline direct injection spark ignition engine. Engine experiments were conducted with both 91 RON E10 gasoline and liquified petroleum gas (LPG) (i.e. autogas) and were compared to legacy gasoline data on the production engine. Geometric compression ratio ( rc) of 13.3:1 was used for both fuels with additional experiments at 16.8:1 for LPG only. Measurements of exhaust soot particle size and number concentrations were made with both fuels. Significant reduction in soot particles across the whole particle size range were achieved with LPG due to the elimination of in-cylinder liquid films. The effects of EGR, late intake valve closing (IVC) and fuel characteristics were investigated through their effects on efficiency, combustion stability and soot production. Results of 47% gross thermal efficiency, and 45% net thermal efficiency at stoichiometric engine operation, at up to 17 bar IMEP and 2000 r/min with 16.8:1 rc were achieved with LPG. Estimated brake efficiency values were compared to a contemporary medium duty diesel engine illustrating the benefits of the chosen path for achieving diesel efficiency parity.

scholarly journals Spark ignition engine performance and emissions in a high compression engine using biogas and methane mixtures without knock occurrence

2015 ◽  
Vol 19 (6) ◽  
pp. 1919-1930 ◽  
Author(s):  
Montoya Gómez ◽  
Arrieta Amell ◽  
Lopez Zapata
Keyword(s):  
Output Power ◽  
Compression Ratio ◽  
Thermal Efficiency ◽  
Combustion Engine ◽  
Maximum Output Power ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Maximum Output ◽  
Engine Operation ◽  
High Compression

With the purpose to use biogas in an internal combustion engine with high compression ratio and in order to get a high output thermal efficiency, this investigation used a diesel engine with a maximum output power 8.5 kW, which was converted to spark ignition mode to use it with gaseous fuels. Three fuels were used: Simulated biogas, biogas enriched with 25% and 50% methane by volume. After conversion, the output power of the engine decreased by 17.64% when using only biogas, where 7 kW was the new maximum output power of the engine. The compression ratio was kept at 15.5:1, and knocking did not occur during engine operation. Output thermal efficiency operating the engine in SI mode with biogas enriched with 50% methane was almost the same compared with the engine running in diesel-biogas dual mode at full load and was greater at part loads. The dependence of the diesel pilot was eliminated when biogas was used in the engine converted in SI mode. The optimum condition of experiment for the engine without knocking was using biogas enriched with 50% methane, with 12 degrees of spark timing advance and equivalence ratio of 0.95, larger output powers and higher values of methane concentration lead the engine to knock operation. The presence of CO2 allows operating engines at high compression ratios with normal combustion conditions. Emissions of nitrogen oxides, carbon monoxide and unburnt methane all in g/kWh decreased when the biogas was enriched with 50% methane.

Simulation of Extended Expansion Lean Burn Spark Ignition Engine

2004 ◽  
Author(s):  
A. Manivannan ◽  
R. Ramprabhu ◽  
P. Tamilporai ◽  
S. Chandrasekaran
Keyword(s):  
Heat Transfer ◽  
Compression Ratio ◽  
Thermal Efficiency ◽  
Numerical Study ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Valve Closure ◽  
Intake Valve ◽  
Lean Burn ◽  
Atkinson Cycle

This paper deals with Numerical Study of 4-stoke, Single cylinder, Spark Ignition, Extended Expansion Lean Burn Engine. Engine processes are simulated using thermodynamic and global modeling techniques. In the simulation study following process are considered compression, combustion, and expansion. Sub-models are used to include effect due to gas exchange process, heat transfer and friction. Wiebe heat release formula was used to predict the cylinder pressure, which was used to find out the indicated work done. The heat transfer from the cylinder, friction and pumping losses also were taken into account to predict the brake mean effective pressure, brake thermal efficiency and brake specific fuel consumption. Extended Expansion Engine operates on Otto-Atkinson cycle. Late Intake Valve Closure (LIVC) technique is used to control the load. The Atkinson cycle has lager expansion ratio than compression ratio. This is achieved by increasing the geometric compression ratio and employing LIVC. Simulation result shows that there is an increase in thermal efficiency up to a certain limit of intake valve closure timing. Optimum performance is attained at 90 deg intake valve closure (IVC) timing further delaying the intake valve closure reduces the engine performance.

scholarly journals The Operating Features of a Stoichiometric, Ammonia and Gasoline Dual Fueled Spark Ignition Engine

2006 ◽  
Author(s):  
Shawn M. Grannell ◽  
Dennis N. Assanis ◽  
Stanislav V. Bohac ◽  
Donald E. Gillespie
Keyword(s):  
Compression Ratio ◽  
Thermal Efficiency ◽  
Maximum Load ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Gaseous Ammonia ◽  
Spark Ignition Engines ◽  
Stoichiometric Mixture ◽  
Brake Thermal Efficiency ◽  
Practical Operation

An overall stoichiometric mixture of air, gaseous ammonia and gasoline was metered into a single cylinder, variable compression ratio, supercharged CFR engine at varying ratios of gasoline to ammonia. The engine was operated such that the combustion was knock-free with minimal roughness for all loads ranging from idle up to a maximum load in the supercharge regime. For a given load, speed, and compression ratio there was a range of ratios of gasoline to ammonia for which knock-free, smooth firing was obtained. This range was investigated at its roughness limit and also at its knock limit. If too much ammonia was used, then the engine fired with an excessive roughness. If too much gasoline was used, then knock-free combustion could not be obtained while the maximum brake torque spark advance was maintained. Stoichiometric operation on gasoline alone was also investigated, for comparison. It was found that a significant fraction of the gasoline used in spark ignition engines could be replaced with ammonia. Operation on mostly gasoline was required near idle. However, mostly ammonia could be used at high load. Operation on ammonia alone was possible at some of the supercharged load points. Generally, the use of ammonia or ammonia with gasoline allowed knock-free operation at higher compression ratios and higher loads than could be obtained with the use of gasoline alone. The use of ammonia/gasoline allowed practical operation at a compression ratio of 12:1 whereas the limit for gasoline alone was 9:1. When running on ammonia/gasoline the engine could be operated at brake mean effective pressures that were more than 50% higher than those achieved with the use of gasoline alone. The maximum brake thermal efficiency achieved with the use of ammonia/gasoline was 32.0% at 10:1 compression ratio and BMEP = 1025 kPa. The maximum brake thermal efficiency possible for gasoline was 24.6% at 9:1 and BMEP = 570 kPa.

scholarly journals ANN Modelling of Propane-Powered 4-Stroke Spark Ignition Engine

2017 ◽  
Vol 11 (10) ◽  
pp. 1
Author(s):  
Jehad A. A. Yamin
Keyword(s):  
Experimental Data ◽  
Compression Ratio ◽  
Thermal Efficiency ◽  
Equivalence Ratio ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Ann Model ◽  
Spark Plug ◽  
Parametric Studies

An ANN model was developed by the authors and tested against experimental data available for an engine as supplied in the manual by the manufacturers. The model was found to perform excellently well by showing similar trends of performance for this engine as well as other engines for which the necessary data was available. This model was then used to perform some parametric studies to improve the performance of an engine using LPG (mainly Propane C3H8) as a fuel. This paper presents discussion on some of the parameters that affect the engine’s thermal efficiency with suggestions to improve it. The effect of equivalence ratio, compression ratio and spark plug location at different speeds on the thermal efficiency have been studied. Based on the engine and the range of variables studied it was found that the best spark plug location was 0.395 for all equivalence ratios studied at CR = 9.

THE OXIDATION, IGNITION, AND DETONATION OF FUEL VAPORS AND GASES: XIII. THE 12:1 COMPRESSION RATIO PERFORMANCE OF THE C.F.R. SPARK IGNITION ENGINE USING TOWN GAS; COMPARISON WITH DIESEL ENGINES

1950 ◽  
Vol 28f (5) ◽  
pp. 134-155 ◽  
Author(s):  
R. O. King ◽  
E. J. Durand ◽  
Bernard D. Wood ◽  
A. B. Allan
Keyword(s):  
Compression Ratio ◽  
Thermal Efficiency ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Coolant Temperature ◽  
Otto Cycle ◽  
Air Supply ◽  
Standard Value ◽  
Gas Ratio ◽  
Gas Supply

The experiments described are part of a series being made to determine the factors which limit the power and efficiency of an Otto cycle spark ignition engine using Toronto town gas nearly free of sulphur. The air supply was unthrottled and power was varied by varying the gas supply. Mixture strength was "correct" at an air-to-gas ratio of 4:1. Trials were run with jacket coolant temperatures of 100°, 140°, 212°, and 295° F., the compression ratio being always 12:1 and the speed 900 r.p.m. A maximum indicated thermal efficiency of 43% was attained with coolant temperatures of 100° and 140° F. and an air-to-gas ratio of 8:1. Thermal efficiency diminished rapidly as air-to-gas ratio was increased and tended to become zero instead of the air standard value. The brake horsepower became zero for an air–gas ratio of approximately 11:1, the mixture strength being then 64% weak. Thus the engine was run at 900 r.p.m. from zero to full load, that is with 100% quality control. The maximum I.M.E.P. of 144 lb./sq. in. was obtained with a jacket coolant temperature of 100° F. The indicated thermal efficiency was then 36% and the mixture 10.7% rich. The performance of the Otto cycle engine could probably be improved by running at higher speeds but even at the relatively low speed of 900 r.p.m. for that type, it compared favorably in most respects with that of the compression ignition type of Diesel engine.

Assessing the Influence of Compression Ratio on Engine Characteristics Including Operational Limits of a Biogas-Fueled Spark-Ignition Engine

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Sachin Kumar Gupta ◽  
Mayank Mittal
Keyword(s):  
Compression Ratio ◽  
Thermal Efficiency ◽  
Internal Combustion Engines ◽  
Fossil Fuels ◽  
Combustion Process ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Operating Range ◽  
Indicated Mean Effective Pressure ◽  
Wide Range

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.

scholarly journals The use of partial fuel stratification to enable stable ultra-lean deflagration-based Spark-Ignition engine operation with controlled end-gas autoignition of gasoline and E85

2019 ◽  
Vol 21 (9) ◽  
pp. 1678-1695
Author(s):  
Zongjie Hu ◽  
Junjie Zhang ◽  
Magnus Sjöberg ◽  
Wei Zeng
Keyword(s):  
Thermal Efficiency ◽  
Direct Injection ◽  
Spark Ignition ◽  
Combustion Efficiency ◽  
Spark Ignition Engine ◽  
Load Range ◽  
Engine Operation ◽  
Lean Mixture ◽  
Stable Combustion ◽  
Fuel Stratification

Lean operation of Spark-Ignition engines can provide higher thermal efficiency compared to standard stoichiometric operation. However, for a homogeneous lean mixture, the associated reduction of flame speeds becomes an important issue from the perspective of robust ignition and fast flame spread throughout the charge. This study is focused on the use of a lean partial fuel stratification strategy that can stabilize the deflagration, while sufficiently fast combustion is ensured via the use of end-gas autoignition. The engine has a spray-guided Direct-Injection Spark-Ignition combustion system and was fueled with either a high-octane certification gasoline or E85. Partial fuel stratification was achieved using several fuel injections during the intake stroke in combination with a small pilot-injection concurrent with the Spark-Ignition. The results reveal that partial fuel stratification enables very stable combustion, offering higher thermal efficiency for parts of the load range in comparison to well-mixed lean and stoichiometric combustion. The heat release and flame imaging demonstrate that the combustion often has three distinct stages. The combustion of the pilot-injected fuel, ignited by the normal spark, acts as a “super igniter,” ensuring a very repeatable initiation of combustion, and flame incandescence reveals locally rich conditions. The second stage is mainly composed of blue flame propagation in a well-mixed lean mixture. The third stage is the compression autoignition of a well-mixed and typically very lean end-gas. The end-gas autoignition is critical for achieving high combustion efficiency, high thermal efficiency, and stable combustion. Partial fuel stratification enables very effective combustion-phasing control, which is critical for controlling the occurrence and intensity of end-gas autoignition. Comparing the gasoline and E85 fuels, it is noted that achieving end-gas autoignition for the higher octane E85 requires a more aggressive compression of the end-gas via the use of a more advanced combustion phasing or higher intake-air temperature.

Development of GDI Engine for Improving Brake Thermal Efficiency Over 44%

2019 ◽  
Author(s):  
Dongwon Jung ◽  
Byeongseok Lee ◽  
Jinwook Son ◽  
Soohyung Woo ◽  
Youngnam Kim
Keyword(s):  
Compression Ratio ◽  
Thermal Efficiency ◽  
Direct Injection ◽  
Stability Limit ◽  
Spark Ignition ◽  
High Load ◽  
Gasoline Direct Injection ◽  
Brake Thermal Efficiency ◽  
Combustion Duration ◽  
Gdi Engine

Abstract This study demonstrates the effects of technologies applied for the development of a gasoline direct injection (GDI) engine for improving the brake thermal efficiency (BTE) over 44%. The GDI engine for the current study is an in-line four-cylinder engine with a displacement of 2156cm3, which has relatively high stroke to bore ratio of 1.4 (110mm stroke and 79mm bore). All experiments have been conducted using a gasoline having RON 92 for stoichiometric operation at 2000RPM. First, since compression ratio is directly related to the thermal efficiency, four compression ratios (14.3, 15.2, 15.8 and 17.2) were explored for operation without exhaust gas recirculation (EGR). Then, for the same four compression ratios, EGR was used to suppress the knock occurrence at high loads with high compression ratio (CR), and its effect on initial and main combustion duration was compared. Second, the shape of intake port was revised to increase tumble flow of in-cylinder charge for reducing combustion duration at low and high load, and extending EGR-stability limit further eventually. Then, as an effective method to ensure stable, complete and fast combustion for EGR-diluted stoichiometric operation, the use of twin spark ignition system is examined by modifying both valve diameter of intake and exhaust, and its effect is compared against that of single spark ignition. In addition, the layout of twin spark ignition was also examined for the location of Front-Rear and Intake-Exhaust. To get the maximum BTE at high load, 12V electronic super charger (eSC) was applied. Under the condition of using 12V eSC, the effect of intake cam duration was identified by increasing from 260deg to 280deg. Finally, 48V eSC was applied with the longer intake camshaft duration of 280deg. As a result, the maximum BTE of 44% can be achieved for stoichiometric operation with EGR.

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