scholarly journals Combustion and Emission Enhancement of a Spark Ignition Two-Stroke Cycle Engine Utilizing Internal and External Exhaust Gas Recirculation Approach at Low-Load Operation

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 609 ◽  
Author(s):  
Amin Mahmoudzadeh Andwari ◽  
Apostolos Pesyridis ◽  
Vahid Esfahanian ◽  
Mohd Said
Keyword(s):  
Weight Ratio ◽  
Exhaust Gas Recirculation ◽  
Exhaust Emissions ◽  
Combustion Stability ◽  
Average Charge ◽  
Exhaust Gas ◽  
Low Load ◽  
Gas Recirculation ◽  
Charge Temperature ◽  
Stroke Cycle

Two-stroke cycle engines have always been prominent due to their distinctive advantage incorporating high power-to-weight ratio, however the drawbacks are poor combustion efficiency, fuel short-circuiting and excessive emission of uHC and CO. These problems are apparent at low-load and speed regions and are the major obstacle to their global acceptance. The deficiencies can be addressed by increasing the in-cylinder average charge temperature employing Exhaust Gas Recirculation (EGR). An experimental study is conducted to investigate the influence of utilizing EGR techniques, including Internal and External EGR, on combustion misfiring occurrence, combustion stability and exhaust emissions using a single cylinder two-stroke SI engine at idling, low and mid-load conditions. From the results, it is observed since the average in-cylinder charge temperature is increased, due to utilizing EGRs, engine’s low and mid-load irregular combustions (misfire) and exhaust emissions are remarkably supressed and almost all of misfire cycles eliminated depending on the percentage of EGRs. In terms of combustion stability, it is agreed in general the application of EGRs improves the cyclic variation of IMEP, Pmax and CA10 compared to conventional operation. However, applying Ex-EGR compared to In-EGR will deteriorate cyclic variability of IMEP and CA10.

A Converted Two-Stroke Cycle Engine for Compression Ignition Combustion

2014 ◽  
Vol 663 ◽  
pp. 331-335 ◽  
Author(s):  
Amin Mahmoudzadeh Andwari ◽  
Azhar Abdul Aziz ◽  
Mohd Farid Muhamad Said ◽  
Zulkarnain Abdul Latiff
Keyword(s):  
Internal Combustion Engines ◽  
Exhaust Gas Recirculation ◽  
Exhaust Emissions ◽  
Exhaust Gas ◽  
Cyclic Variation ◽  
Cyclic Variability ◽  
Auto Ignition ◽  
Compression Ignition Combustion ◽  
Gas Recirculation ◽  
Stroke Cycle

A new kind of alternative combustion concept that has attracted attention intensively in recent years is called controlled auto-ignition (CAI) combustion. CAI combustion has been proposed and partially implemented with the aim of both improving the thermal efficiency of internal combustion engines, achieving cleaner exhaust emissions and lower cyclic variation. An experimental study is conducted through a CAI two-stroke cycle engine in order to investigate the influence of internal exhaust gas recirculation (In-EGR) and external exhaust gas recirculation (Ex-EGR) variation in relation to combustion cyclic variability and exhaust emissions characteristics. Results implied that cyclic variation of both combustion-related and pressure-related parameter is substantially improved. Furthermore remarkable decreased exhaust emissions, unburned hydrocarbon (uHC), carbon monoxide (CO) and nitric dioxide (NOX), was observed.

A comparative study into the effects of pre and post catalyst exhaust gas recirculation on the onset of knock

2020 ◽  
pp. 146808742096229
Author(s):  
Dominic Parsons ◽  
Simon Orchard ◽  
Nick Evans ◽  
Umud Ozturk ◽  
Richard Burke ◽  
...  
Keyword(s):  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Engine Combustion ◽  
Low Load ◽  
Fine Control ◽  
Novel Method ◽  
Gdi Engine ◽  
Stochastic Phenomena ◽  
Gas Recirculation ◽  
Onset Angle

Exhaust gas recirculation (EGR) is proven as a valuable technology for controlling knock whilst maintaining lambda one operation, and is also capable of providing efficiency gains at low load. Despite this few studies in the literature address the question of EGR composition effects, namely whether the EGR gas is sourced from before or after the catalyst, and this remains an area which is often overlooked whilst investigating EGR performance. This paper demonstrates a novel method combining experiment air-path emulation and in-depth data processes to compare the effect of EGR catalysis on the angle of knock onset in a 1L GDI engine. Since initial temperature and pressure have a significant impact on knocking behaviour, an artificial boosting rig replaced the turbomachinery. This enabled fine control over the engine boundary conditions to ensure parity between the catalysed and un-catalysed cases. To overcome the difficulty of comparing stochastic phenomena in an inherently variable dataset, a pairing method was combined with Shahlari and Ghandhi’s angle of knock onset determination method to assess the effects of EGR composition on knock onset for EGR rates ranging from 9% to 18%. The air path emulation system stabilised the engine combustion to provide a suitably rich dataset for analysing knock using the pairing method. Catalysed EGR improved the mean knock onset angle by 0.55 CAD, but due to the inherent variability in cylinder pressure data this only equated to a 58.3% chance of a later knock onset angle for catalysed EGR in any given pair of comparative cycles.

Hydrogen enrichment: A way to maintain combustion stability in a natural gas fuelled engine with exhaust gas recirculation, the potential of fuel reforming

2001 ◽  
Vol 215 (3) ◽  
pp. 405-418 ◽  
Author(s):  
S. Allenby ◽  
W-C. Chang ◽  
A. Megaritis ◽  
M. L. Wyszyński
Keyword(s):  
Natural Gas ◽  
Exhaust Gas Recirculation ◽  
Combustion Stability ◽  
Exhaust Gas ◽  
Fuel Reforming ◽  
Rapid Reduction ◽  
Indicated Mean Effective Pressure ◽  
Hydrogen Enrichment ◽  
Gas Recirculation ◽  
Operating Points

An experimental study was carried out to evaluate the potential of hydrogen enrichment to increase the tolerance of a stoichiometrically fuelled natural gas engine to high levels of dilution by exhaust gas recirculation (EGR). This provides significant gains in terms of exhaust emissions without the rapid reduction in combustion stability typically seen when applying EGR to a methane-fuelled engine. Presented results give the envelope of benefits from hydrogen enrichment. In parallel, the performance of a catalytic exhaust gas reforming reactor was investigated in order that it could be used as an onboard source of hydrogen-rich EGR. It was shown that sufficient hydrogen was generated with currently available prototype catalysts to allow the engine, at the operating points considered, to tolerate up to 25 per cent EGR, while maintaining a coefficient of variability of indicated mean effective pressure below 5 per cent. This level of EGR gives a reduction in NO emissions greater than 80 per cent in all test cases.

Extending Lean and Exhaust Gas Recirculation-Dilute Operating Limits of a Modern Gasoline Direct-Injection Engine Using a Low-Energy Transient Plasma Ignition System

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
James Sevik ◽  
Thomas Wallner ◽  
Michael Pamminger ◽  
Riccardo Scarcelli ◽  
Dan Singleton ◽  
...  
Keyword(s):  
Direct Injection ◽  
Exhaust Gas Recirculation ◽  
Low Energy ◽  
Gasoline Direct Injection ◽  
Combustion Stability ◽  
Exhaust Gas ◽  
Ignition System ◽  
Plasma Ignition ◽  
Gas Recirculation ◽  
Transient Plasma

The efficiency improvement and emissions reduction potential of lean and exhaust gas recirculation (EGR)-dilute operation of spark-ignition gasoline engines is well understood and documented. However, dilute operation is generally limited by deteriorating combustion stability with increasing inert gas levels. The combustion stability decreases due to reduced mixture flame speeds resulting in significantly increased combustion initiation periods and burn durations. A study was designed and executed to evaluate the potential to extend lean and EGR-dilute limits using a low-energy transient plasma ignition system. The low-energy transient plasma was generated by nanosecond pulses and its performance compared to a conventional transistorized coil ignition (TCI) system operated on an automotive, gasoline direct-injection (GDI) single-cylinder research engine. The experimental assessment was focused on steady-state experiments at the part load condition of 1500 rpm 5.6 bar indicated mean effective pressure (IMEP), where dilution tolerance is particularly critical to improving efficiency and emission performance. Experimental results suggest that the energy delivery process of the low-energy transient plasma ignition system significantly improves part load dilution tolerance by reducing the early flame development period. Statistical analysis of relevant combustion metrics was performed in order to further investigate the effects of the advanced ignition system on combustion stability. Results confirm that at select operating conditions EGR tolerance and lean limit could be improved by as much as 20% (from 22.7 to 27.1% EGR) and nearly 10% (from λ = 1.55 to 1.7) with the low-energy transient plasma ignition system.

Effect of Turbulence and External Exhaust Gas Recirculation on HCCI Combustion Mode and Exhaust Emissions

2009 ◽  
Vol 23 (9) ◽  
pp. 4295-4303 ◽  
Author(s):  
Francisco J. Jiménez-Espadafor ◽  
Miguel Torres Garcia ◽  
José A. Correa Herrero ◽  
José A. Becerra Villanueva
Keyword(s):  
Exhaust Gas Recirculation ◽  
Exhaust Emissions ◽  
Exhaust Gas ◽  
Combustion Mode ◽  
Hcci Combustion ◽  
Gas Recirculation

The effects of exhaust gas recirculation on diesel combustion and emissions

2000 ◽  
Vol 1 (1) ◽  
pp. 107-126 ◽  
Author(s):  
N Ladommatos ◽  
S Abdelhalim ◽  
H Zhao
Keyword(s):  
Carbon Dioxide ◽  
Heat Capacity ◽  
Diesel Engine ◽  
Combustion Process ◽  
Exhaust Gas Recirculation ◽  
Particulate Emissions ◽  
Exhaust Gas ◽  
Particulate Emission ◽  
Gas Recirculation ◽  
Charge Temperature

An investigation was conducted with the aim of identifying and quantifying the effects of exhaust gas recirculation (EGR) on diesel engine combustion and exhaust emissions. Five effects of EGR were identified and investigated experimentally: the reduction in oxygen supply to the engine, participation in the combustion process of carbon dioxide and water vapour present in the EGR, increase in the specific heat capacity of the engine inlet charge, increased inlet charge temperature and reduction in the inlet charge mass flowrate arising from the use of hot EGR. The experimental methodology developed allowed each one of these effects to be investigated and quantified separately. The investigation was carried out on a high-speed, direct injection diesel engine, running at an intermediate speed and load. A limited number of tests were also conducted in an optically accessible diesel engine, which established the effects of EGR on local flame temperature. Finally, tests were conducted with simulated EGR being used additionally to the engine air supply. This contrasts with the conventional use of EGR, whereby EGR replaces some of the air supplied to the engine. It was found that the first effect of EGR (reduction in the oxygen flowrate to the engine) was substantial and resulted in very large reductions in exhaust NOx at the expense of higher particulate emissions. The second and third effects (participation of carbon dioxide and water vapour in the combustion process and increase in the charge specific heat capacity) were almost insignificant. The fourth effect (higher inlet charge temperature) increased both exhaust NOx and particulate emissions. The fifth effect (reduction in the inlet charge due to thermal throttling) reduced NOx but raised particulate emission. Finally, when EGR was used additionally to the inlet air charge (rather than displacing air), substantial reductions in NOx were recorded with little increase in particulate emission.

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