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.

The effects of cylinder deactivation on the thermal behaviour and fuel economy of a three-cylinder direct injection spark ignition gasoline engine

2018 ◽  
Vol 233 (11) ◽  
pp. 2838-2849
Author(s):  
Michael McGhee ◽  
Ziman Wang ◽  
Alexander Bech ◽  
Paul J Shayler ◽  
Dennis Witt
Keyword(s):  
Fuel Economy ◽  
Gasoline Engine ◽  
Thermal State ◽  
Direct Injection ◽  
Spark Ignition ◽  
Combustion Efficiency ◽  
Spark Ignition Engine ◽  
Engine Fuel ◽  
Cylinder Deactivation ◽  
Direct Injection Spark Ignition

The changes in thermal state, emissions and fuel economy of a 1.0-L, three-cylinder direct injection spark ignition engine when a cylinder is deactivated have been explored experimentally. Cylinder deactivation improved engine fuel economy by up to 15% at light engine loads by reducing pumping work, raising indicated thermal efficiency and raising combustion efficiency. Penalties included an increase in NOx emissions and small increases in rubbing friction and gas work losses of the deactivated cylinder. The cyclic pressure variation in the deactivated cylinder falls rapidly after deactivation through blow-by and heat transfer losses. After around seven cycles, the motoring loss is ~2 J/cycle. Engine structural temperatures settle within an 8- to 13-s interval after a switch between two- and three-cylinder operation. Engine heat rejection to coolant is reduced by ~13% by deactivating a cylinder, extending coolant warm-up time to thermostat-opening by 102 s.

Effects of Blending Gasoline With Ethanol and Butanol on Engine Efficiency and Emissions Using a Direct-Injection, Spark-Ignition Engine

2009 ◽  
Author(s):  
Christopher Cooney ◽  
Thomas Wallner ◽  
Steve McConnell ◽  
Jeffrey C. Gillen ◽  
Clint Abell ◽  
...  
Keyword(s):  
Alternative Fuels ◽  
Direct Injection ◽  
Substantial Reduction ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Engine Operation ◽  
Advanced Biofuels ◽  
Engine Calibration ◽  
Combustion Behavior ◽  
Test Engine

The new U.S. Renewable Fuel Standard requires an increase of ethanol and advanced biofuels to 36 billion gallons by 2022. Due to its high octane number, renewable character and minimal toxicity, ethanol was believed to be one of the most favorable alternative fuels to displace gasoline in spark-ignited engines. However, ethanol fuel results in a substantial reduction in vehicle range when compared to gasoline. In addition, ethanol is fully miscible in water which requires blending at distribution sites instead of the refinery. Butanol, on the other hand, has an energy density comparable to gasoline and lower affinity for water than ethanol. Butanol has recently received increased attention due to its favorable fuel properties as well as new developments in production processes. The advantageous properties of butanol warrant a more in-depth study on the potential for butanol to become a significant component of the advanced biofuels mandate. This study evaluates the combustion behavior, performance, as well as the regulated engine-out emissions of ethanol and butanol blends with gasoline. Two of the butanol isomers; 1-butanol as well as iso-butanol, were tested as part of this study. The evaluation includes gasoline as a baseline, as well as various ethanol/gasoline and butanol/gasoline blends up to a volume blend ratio of 85% of the oxygenated fuel. The test engine is a spark ignition, direct-injection, (SIDI), four-cylinder test engine equipped with pressure transducers in each cylinder. These tests were designed to evaluate a scenario in terms of using these alcohol blends in an engine calibrated for pump gasoline operation. Therefore no modifications to the engine calibration were performed. Following this analysis of combustion behavior and emissions with the base engine calibration, future studies will include detailed heat release analysis of engine operation without exhaust gas recirculation. Also, knock behavior of the different fuel blends will be studied along with unregulated engine out emissions.

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.

Effects of Valve Deactivation on Thermal Efficiency in a Direct Injection Spark Ignition Engine under Dilute Conditions

2018 ◽  
Author(s):  
Philip John Roberts ◽  
Alexandros Kountouriotis ◽  
Pawel Okroj ◽  
Pavlos Aleiferis ◽  
Brian Cooper
Keyword(s):  
Thermal Efficiency ◽  
Direct Injection ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Direct Injection Spark Ignition

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.

Soot Development in an Optical Direct Injection Spark Ignition Engine Fueled with Isooctane

2021 ◽  
Vol 22 (2) ◽  
pp. 455-463
Author(s):  
Fangxi Xie ◽  
Miaomiao Zhang ◽  
Yongzhen Wang ◽  
Yan Su ◽  
Wei Hong ◽  
...  
Keyword(s):  
Direct Injection ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Direct Injection Spark Ignition
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