The Potential of a Separated Electric Compound Spark Ignition Engine for Hybrid Vehicle Application

Author(s):  
Emiliano Pipitone ◽  
Salvatore Caltabellotta

Abstract In-cylinder expansion of internal combustion engines based on Diesel or Otto cycles cannot be completely brought down to ambient pressure, causing a 20% theoretical energy loss. Several systems have been implemented to recover and use this energy such as turbocharging, turbo-mechanical and turbo-electrical compounding, or the implementation of Miller Cycles. In all these cases however, the amount of energy recovered is limited allowing the engine to reach an overall efficiency incremental improvement between 4% and 9%. Implementing an adequately designed expander-generator unit could efficiently recover the unexpanded exhaust gas energy and improve efficiency. In this work, the application of the expander-generator unit to a hybrid propulsion vehicle is considered, where the onboard energy storage receives power produced by an expander-generator, which could hence be employed for vehicle propulsion through an electric drivetrain. Starting from these considerations, a simple but effective modelling approach is used to evaluate the energetic potential of a spark-ignition engine electrically supercharged and equipped with an exhaust gas expander connected to an electric generator. The overall efficiency was compared to a reference turbocharged engine within a hybrid vehicle architecture. It was found that, if adequately recovered, the unexpanded gas energy could reduce engine fuel consumption and related pollutant emissions by 4% to 12%, depending on overall power output.

2021 ◽  
Vol 11 (13) ◽  
pp. 6035
Author(s):  
Luigi Teodosio ◽  
Luca Marchitto ◽  
Cinzia Tornatore ◽  
Fabio Bozza ◽  
Gerardo Valentino

Combustion stability, engine efficiency and emissions in a multi-cylinder spark-ignition internal combustion engines can be improved through the advanced control and optimization of individual cylinder operation. In this work, experimental and numerical analyses were carried out on a twin-cylinder turbocharged port fuel injection (PFI) spark-ignition engine to evaluate the influence of cylinder-by-cylinder variation on performance and pollutant emissions. In a first stage, experimental tests are performed on the engine at different speed/load points and exhaust gas recirculation (EGR) rates, covering operating conditions typical of Worldwide harmonized Light-duty vehicles Test Cycle (WLTC). Measurements highlighted relevant differences in combustion evolution between cylinders, mainly due to non-uniform effective in-cylinder air/fuel ratio. Experimental data are utilized to validate a one-dimensional (1D) engine model, enhanced with user-defined sub-models of turbulence, combustion, heat transfer and noxious emissions. The model shows a satisfactory accuracy in reproducing the combustion evolution in each cylinder and the temperature of exhaust gases at turbine inlet. The pollutant species (HC, CO and NOx) predicted by the model show a good agreement with the ones measured at engine exhaust. Furthermore, the impact of cylinder-by-cylinder variation on gaseous emissions is also satisfactorily reproduced. The novel contribution of present work mainly consists in the extended numerical/experimental analysis on the effects of cylinder-by-cylinder variation on performance and emissions of spark-ignition engines. The proposed numerical methodology represents a valuable tool to support the engine design and calibration, with the aim to improve both performance and emissions.


Author(s):  
Karthik Nithyanandan ◽  
Chia-fon F. Lee ◽  
Han Wu ◽  
Jiaxiang Zhang

Acetone-Butanol-Ethanol (ABE), an intermediate product in the ABE fermentation process for producing bio-butanol, is considered a promising alternative fuel because it not only preserves the advantages of oxygenated fuels which typically emit fewer pollutants, but also lowers the cost of fuel recovery for each individual component during fermentation. An experiment was conducted using a Ford single-cylinder spark-ignition (SI) research engine to investigate the potential of ABE as an SI engine fuel. Blends of pure gasoline and ABE, ranging from 0% to 80% vol. ABE, were created and the performance and emission characteristics were compared with pure gasoline as the baseline. Measurements of brake torque and exhaust gas temperature along with in-cylinder pressure traces were used to study the performance of the engine and measurements of emissions of unburned hydrocarbons, carbon monoxide, and nitrogen oxides were used to compare the fuels in terms of combustion byproducts. Experiments were performed at a constant engine speed and a comparison was made on the basis of similar power output (Brake Mean Effective Pressure (BMEP)). In-cylinder pressure data showed that the peak pressure of all the blends was slightly lower than that of gasoline, except for ABE80 which showed a slightly higher and advanced peak relative to gasoline. ABE showed an increase in brake specific fuel consumption (BSFC); while exhaust gas temperature and nitrogen oxide measurements show that ABE combusts at a lower peak temperature. The emissions of unburned hydrocarbons were higher compared to those of gasoline but the CO emissions were lower. Of particular interest is the combined effect of the higher laminar flame speed (LFS) and higher latent heat of vaporization of ABE fuels on the combustion process.


2021 ◽  
Vol 21 (2) ◽  
pp. 80-95
Author(s):  
Noor Hassan ◽  
Adel M Saleh

Pollutants emitted from internal combustion engines cause significant environmental pollution, and the reduction of these pollutants is the goal of all. The deterioration of air quality is increasing year after year due to increasing the population and cars and low awareness of pollution reduction. In this study, the impact of recycling of exhaust gas in a spark ignition engine was tested on the NOx emitted from it, which is considered one of the most dangerous environmental pollutant. The results of the study showed that the brake specific fuel consumption increases by increasing the amount of the EGR interning the engine, also the brake thermal efficiency increases and the volumetric efficiency decreases with this increase. The NOx concentrations emitted are significantly reduced when high rates of EGR (15% and 20%) are added. The use of high octane fuel RON94.5 has helped to reduce the expected EGR damage, such as greater reduction in the specific fuel consumption, or a greater reduction in the volumetric efficiency.


2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Melih Yıldız ◽  
Bilge Albayrak Çeper

For years, the goal of vehicle manufacturers; combustion control of spark ignition engines, ease of passage between the various cycles For years, the goal of vehicle manufacturers; combustion control of spark ignition engines, ease of passage between the various cycles, low emission values of diesel engines, high fuel economy and output power, thereby achieving optimum values in internal combustion engines. In this context, to improve the engine performance and increase the volumetric and thermal efficiency of the engine in all operating conditions to minimize the power losses and to reduce the exhaust emissions in order to obtain the maximum power, most economical and without environmental pollution, continues to be updated. In this study, the optimum working map of the engine was obtained by considering the power, torque, specific fuel consumption, cylinder pressure, exhaust gas temperature, thermal efficiency, average effective pressure, heat dissipation rate and emissions of four stroke, two cylinder, spark ignition SI engine fuel.


Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 691
Author(s):  
Andrzej Żółtowski ◽  
Wojciech Gis

Ammonia is a toxic exhaust component emitted from internal combustion engines. Both pure ammonia and the products of its reaction with nitrogen and sulfur compounds, being the source of particulate matter (PM) emissions, are dangerous for human health and life. The aim of the article was to demonstrate that NH3 can be produced in exhaust gas after-treatment systems of spark-ignition (SI) engines used in light-duty vehicles. In some cases, NH3 occurs in high enough concentrations that can be harmful and dangerous. It would be reasonable to collect research data regarding this problem and consider the advisability of limiting these pollutant emissions in future regulations. The article presents the results of the spark-ignition engine testing on an engine test bench and discusses the impact of the air–fuel ratio regulation and some engine operating parameters on the concentration of NH3. It has been proven that in certain engine operating conditions and a combination of circumstances like the three-way catalytic reactor (TWC) temperature and periodic enrichment of the air–fuel mixture may lead to excessive NH3 emissions resulting from the NO conversion in the catalytic reactor. This is a clear disadvantage due to the lack of limitation of these pollutant emissions by the relevant type-approval regulations. This article should be a contribution to discussion among emissions researchers whether future emission regulations (e.g., Euro 7 or Euro VII) should include a provision to reduce NH3 emissions from all vehicles.


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).


Author(s):  
Nicolas Iafrate ◽  
Anthony Robert ◽  
Jean-Baptiste Michel ◽  
Olivier Colin ◽  
Benedicte Cuenot ◽  
...  

Downsized spark ignition engines coupled with a direct injection strategy are more and more attractive for car manufacturers in order to reduce pollutant emissions and increase efficiency. However, the combustion process may be affected by local heterogeneities caused by the interaction between the spray and turbulence. The aim for car manufacturers of such engine strategy is to create, for mid-to-high speeds and mid-up-high loads, a mixture which is as homogeneous as possible. However, although injection occurs during the intake phase, which favors homogeneous mixing, local heterogeneities of the equivalence ratio are still observed at the ignition time. The analysis of the mixture preparation is difficult to perform experimentally because of limited optical accesses. In this context, numerical simulation, and in particular Large Eddy Simulation (LES) are complementary tools for the understanding and analysis of unsteady phenomena. The paper presents the LES study of the impact of direct injection on the mixture preparation and combustion in a spark ignition engine. Numerical simulations are validated by comparing LES results with experimental data previously obtained at IFPEN. Two main analyses are performed. The first one focuses on the fuel mixing and the second one concerns the effect of the liquid phase on the combustion process. To highlight these phenomena, simulations with and without liquid injection are performed and compared.


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