Effects of second injection timing on combustion characteristics of the spark ignition direct injection gasoline engines with dimethyl ether enrichment in the intake port

Energy ◽  
2019 ◽  
Vol 180 ◽  
pp. 10-18 ◽  
Author(s):  
Lei Shi ◽  
Changwei Ji ◽  
Shuofeng Wang ◽  
Teng Su ◽  
Xiaoyu Cong ◽  
...  
Author(s):  
Jianye Su ◽  
Weiyang Lin ◽  
Jeff Sterniak ◽  
Min Xu ◽  
Stanislav V. Bohac

Spark ignition direct injection (SIDI) gasoline engines, especially in downsized boosted engine platforms, are increasing their market share relative to port fuel injection (PFI) engines in U.S., European and Chinese vehicles due to better fuel economy by enabling higher compression ratios and higher specific power output. However, particulate matter (PM) emissions from engines are becoming a concern due to adverse human health and environment effects, and more stringent emission standards. To conduct a PM number and size comparison between SIDI and PFI systems, a 2.0 L boosted gasoline engine has been equipped and tested with both systems at different loads, air fuel ratios, spark timings, fuel pressures and injection timings for SIDI operation and loads, air fuel ratios and spark timings for PFI operation. Regardless of load, air fuel ratio, spark timing, fuel pressure, and injection timing, particle size distribution from SIDI and PFI is shown to be bimodal, exhibiting nucleation and accumulation mode particles. SIDI produces particle numbers that are an order of magnitude greater than PFI. Particle number can be reduced by retarding spark timing and operating the engine lean, both for SIDI and PFI operation. Increasing fuel injection pressure and optimizing injection timing with SIDI also reduces PM emissions. This study provides insight into the differences in PM emissions from boosted SIDI and PFI engines and an evaluation of PM reduction potential by varying engine operating parameters in boosted SIDI and PFI gasoline engines.


2014 ◽  
Vol 1070-1072 ◽  
pp. 1835-1839
Author(s):  
Wei Bo Shi ◽  
Xiu Min Yu

This paper reviews and summarizes recent developments in hydrogen and gasoline mixtures powered engine research. According to the hydrogen and gasoline injection location, engine can be divided into three categories: hydrogen intake port injection, gasoline direct injection; Hydrogen direct injection, gasoline intake port injection; hydrogen and gasoline intake port injection. Different gasoline and hydrogen injection location determines the engines have different advantages. Follow an overview of spark ignition engine using hydrogen and gasoline mixtures, general trade-off when operating engine on hydrogen and gasoline mixtures are analyzed and highlights regarding accomplishments in efficiency improvement and emissions reduction are presented. These include estimates of efficiency potential of hydrogen and gasoline engines, fuel economy and emissions.


Author(s):  
Jianye Su ◽  
Weiyang Lin ◽  
Jeff Sterniak ◽  
Min Xu ◽  
Stanislav V. Bohac

Spark ignition direct injection (SIDI) gasoline engines, especially in downsized boosted engine platforms, are increasing their market share relative to port fuel injection (PFI) engines in U.S., European and Chinese vehicles due to better fuel economy by enabling higher compression ratios and higher specific power output. However, particulate matter (PM) emissions from engines are becoming a concern due to adverse human health and environment effects, and more stringent emission standards. To conduct a PM number and size comparison between SIDI and PFI systems, a 2.0 L boosted gasoline engine has been equipped and tested with both systems at different loads, air fuel ratios, spark timings, fuel pressures and injection timings for SIDI operation and loads, air fuel ratios and spark timings for PFI operation. Regardless of load, air fuel ratio, spark timing, fuel pressure, and injection timing, particle size distribution from SIDI and PFI is shown to be bimodal, exhibiting nucleation and accumulation mode particles. SIDI produces particle numbers that are an order of magnitude greater than PFI. Particle number can be reduced by retarding spark timing and operating the engine lean, both for SIDI and PFI operation. Increasing fuel injection pressure and optimizing injection timing with SIDI also reduces PM emissions. This study provides insight into the differences in PM emissions from boosted SIDI and PFI engines and an evaluation of PM reduction potential by varying engine operating parameters in boosted SIDI and PFI gasoline engines.


2012 ◽  
Vol 614-615 ◽  
pp. 337-342
Author(s):  
Li Luo ◽  
Bin Xu ◽  
Zhi Hao Ma ◽  
Jian Wu ◽  
Ming Li

In this study, the effect of injection timing on combustion characteristics of a direct injection, electronically controlled, high pressure, common rail, turbocharged and intercooled engine fuelled with different pistacia chinensis bunge seed biodiesel/diesel blends has been experimentally investigated. The results indicated that brake specific fuel consumption reduces with the increasing of fuel injection advance angle and enhances with the increasing of biodiesel content in the blends. The peak of cylinder pressure and maximum combustion temperature increase evidently with the increment of fuel injection advance angle. However, the combustion of biodiesel blends starts earlier than diesel at the same fuel injection advance angle. At both conditions, the combustion duration and the peak of heat release rate are insensitive to the changing of injection timing.


Author(s):  
Hyun Kyu Suh ◽  
Hyun Gu Roh ◽  
Chang Sik Lee

The aim of this work is to investigate the effect of the blending ratio and pilot injection on the spray and combustion characteristics of biodiesel fuel and compare these factors with those of diesel fuel in a direct injection common-rail diesel engine. In order to study the factors influencing the spray and combustion characteristics of biodiesel fuel, experiments involving exhaust emissions and engine performance were conducted at various biodiesel blending ratios and injection conditions for engine operating conditions. The macroscopic and microscopic spray characteristics of biodiesel fuel, such as injection rate, split injection effect, spray tip penetration, droplet diameter, and axial velocity distribution, were compared with the results from conventional diesel fuel. For biodiesel blended fuel, it was revealed that a higher injection pressure is needed to achieve the same injection rate at a higher blending ratio. The spray tip penetration of biodiesel fuel was similar to that of diesel. The atomization characteristics of biodiesel show that it has higher Sauter mean diameter and lower spray velocity than conventional diesel fuel due to high viscosity and surface tension. The peak combustion pressures of diesel and blending fuel increased with advanced injection timing and the combustion pressure of biodiesel fuel is higher than that of diesel fuel. As the pilot injection timing is retarded to 15deg of BTDC that is closed by the top dead center, the dissimilarities of diesel and blending fuels combustion pressure are reduced. It was found that the pilot injection enhanced the deteriorated spray and combustion characteristics of biodiesel fuel caused by different physical properties of the fuel.


Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5223
Author(s):  
Guanting Li ◽  
Xiumin Yu ◽  
Ping Sun ◽  
Decheng Li

Split hydrogen direct injection (SHDI) has been proved capable of better efficiency and fewer emissions. Therefore, to investigate SHDI deeply, a numerical study on the effect of second injection timing was presented at a gasoline/hydrogen spark ignition (SI) engine with SHDI. With an excess air ratio of 1.5, five different second injection timings achieved five kinds of hydrogen mixture distribution (HMD), which was the main factor affecting the engine performances. With SHDI, since the HMD is manageable, the engine can achieve better efficiency and fewer emissions. When the second injection timing was 105° crank angle (CA) before top dead center (BTDC), the Pmax was the highest and the position of the Pmax was the earliest. Compared with the single hydrogen direct injection (HDI), the NOX, CO and HC emissions with SHDI were reduced by 20%, 40% and 72% respectively.


2019 ◽  
Vol 22 (1) ◽  
pp. 140-151 ◽  
Author(s):  
Xue-Qing Fu ◽  
Bang-Quan He ◽  
Si-Peng Xu ◽  
Tao Chen ◽  
Hua Zhao ◽  
...  

Lean-burn combustion is effective in reducing fuel consumption of gasoline engines because of the higher specific heat ratio of the fuel lean mixture and reduced heat loss from lower combustion temperature. However, its application to real engines is hampered by the unstable ignition, high cyclic variability, and partial-burn due to slower combustion, as well as the restricted maximum lean-burn air/fuel ratio limit and the insufficiently low nitrogen oxides emission. Multi-point micro-flame-ignited hybrid combustion has been proposed and applied to extend the lean burn limit of premixed gasoline and air mixture. To achieve micro-flame-ignited combustion in premixed lean gasoline mixture formed by port fuel injection, a small amount of dimethyl ether is injected directly into the cylinder of a four-stroke gasoline engine to control and accelerate the ignition and combustion process so that the engine could be operated with the overall excess air coefficient (Lambda) of 1.9. The results show that heat release processes can be grouped into three forms, that is, ramp type, double-peak type, and trapezoid type. Regardless of single or split injections, direct injection timing of dimethyl ether dominates the features of heat release. The ramp type occurs at early injection timing while the double-peak type takes place at late injection timing. Trapezoid type appears between the above two types. Dimethyl ether injection timing controls the ignition timing and has less effect on combustion duration. Single injection of dimethyl ether leads to much earlier ignition timing and slightly longer combustion duration, forming higher nitrogen oxides emissions than the split injections. Ultra-low nitrogen oxides emissions and higher thermal efficiency are achieved in the ramp type combustion compared to the other two types of combustion in both injection approaches.


2019 ◽  
Vol 21 (2) ◽  
pp. 302-318 ◽  
Author(s):  
Carl-Philipp Ding ◽  
David Vuilleumier ◽  
Namho Kim ◽  
David L Reuss ◽  
Magnus Sjöberg ◽  
...  

Mid-level ethanol/gasoline blends can provide knock resistance benefits for stoichiometric spark-ignition engine operation, but previous studies have identified challenges associated with spray impingement and wall wetting, leading to excessive particulate matter emissions. At the same time, stratified-charge spark-ignition operation can provide increased thermal efficiency, but care has to be exercised to avoid excessive in-cylinder soot formation. In support of the use of mid-level ethanol/gasoline blends in advanced spark-ignition engines, this study presents spray and fuel-film measurements in a direct-injection spark-ignition engine operated with a 30 vol.%/70 vol.% ethanol/gasoline blend (E30). Crank-angle resolved fuel-film measurements at the piston surface are conducted using two different implementations of the refractive index matching technique. A small-angle refractive index matching implementation allows quantification of the wetted area, while a large-angle refractive index matching implementation enables semi-quantitative measurements of fuel-film thickness and volume, in addition to fuel-film area. The fuel-film measurements show that both the amount of fuel deposited on the piston and the shape of the fuel-film patterns are strongly influenced by the injection timing, duration, intake pressure, and coolant temperature. For combinations of high in-cylinder gas density and long injection duration, merging of the individual spray plumes, commonly referred to as spray collapse, can cause a dramatic change to the shape and thickness of the wall fuel films. Overall, the study provides guidance to engine designers aiming at minimizing wall wetting through tailored combinations of injection timings and durations.


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