Experimental Investigation of Injection Strategies on Low Temperature Combustion Fuelled with Gasoline in a Compression Ignition Engine

The present study focuses on the experimental investigation on the effect of fuel injection strategies on LTC with gasoline on a single-cylinder CI engine. Firstly, the engine performance and emissions have been explored by sweeping SOI1 and split percentage for the load of 0.9 MPa IMEP at an engine speed of 1500 rpm. Then, the double-injection strategy has been tested for load expansion compared with single-injection. The results indicate that, with the fixed CA50, the peak HRR is reduced by advancing SOI1 and increasing split percentage gradually. Higher indicated thermal efficiency, as well as lower MPRR and COV, can be achieved simultaneously with later SOI1 and higher split percentage. As split percentage increases,NOXemission decreases but soot emission increases. CO and THC emissions are increased by earlier SOI1, resulting in a slight decrease in combustion efficiency. Compared with single-injection, the double-injection strategy enables successful expansion of high-efficiency and clean combustion region, with increasing soot, CO, and THC emissions at high loads and slightly declining combustion efficiency and indicated thermal efficiency, however. MPRR and soot emission are considered to be the predominant constraints to the load expansion of gasoline LTC, and they are related to their trade-off relationship.

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Effect of Injection Timing on PPCI and MPCI Mode Fueled With Straight-Run Naphtha

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4025722 ◽

2013 ◽

Vol 136 (3) ◽

Cited By ~ 3

Author(s):

Hongqiang Yang ◽

Shijin Shuai ◽

Zhi Wang ◽

Jianxin Wang

Keyword(s):

Diesel Fuel ◽

Single Injection ◽

Operating Conditions ◽

Premixed Combustion ◽

Spray Combustion ◽

Injection Timing ◽

Soot Emission ◽

Compression Ignition ◽

Injection Strategy ◽

Injection Strategies

Partially premixed compression ignition (PPCI) and multiple premixed compression ignition (MPCI) mode of straight-run naphtha have been investigated under different injection strategies. The MPCI mode is realized by the multiple premixed combustion processes in a sequence of “spray-combustion-spray-combustion” around the compression top dead center. The spray and combustion events are preferred to be completely separated, without any overlap in the temporal sequence in order to ensure the multiple-stage premixed compression ignition. The PPCI mode is well known as the “spray-spray-combustion” sequence, with the start of combustion separated from the end of injection. Straight-run naphtha with a research octane number (RON) of 58.8 is tested in a single cylinder compression ignition engine whose compression ratio is 16.7 and displacement is 0.5 l. Double and triple injection strategies are investigated as the last injection timing sweeping at 1.0 MPa IMEP and 1800 rpm conditions. The MPCI mode is achieved using the double injection strategy, but its soot emission is higher than the PPCI mode under triple injection strategy. This is mainly because of the lower RON of the straight-run naphtha and the ignition delay is too short to form an ideally premixed combustion process after the second injection of straight-run naphtha. Diesel fuel is also tested under the same operating conditions, except for employing a single injection strategy. The naphtha PPCI and MPCI mode both have lower fuel consumption and soot emission than diesel fuel single injection mode, but the THC emissions are both higher than that of diesel fuel.

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Influence of injection strategies on knock resistance and combustion characteristics in a DISI engine

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/0954407018804118 ◽

2018 ◽

Vol 233 (10) ◽

pp. 2637-2649

Author(s):

Haiqiao Wei ◽

Jie Yu ◽

Aifang Shao ◽

Lei Zhou ◽

Jianxiong Hua ◽

...

Keyword(s):

Single Injection ◽

Operating Conditions ◽

Spark Ignition Engine ◽

Combustion Stability ◽

Injection Timing ◽

Split Injection ◽

Injection Strategy ◽

Double Injection ◽

The Impact ◽

Injection Strategies

The combustion of a direct injection spark ignition engine is significantly affected by the fuel injection strategy due to the impact this strategy has on the gas-mixture formation and the turbulence flow. However, comprehensive assessments on both knock and engine performances for different injection strategies are generally lacking. Therefore, the main objective of the present study is to provide an experimental evidence of how a single injection strategy and a split injection strategy compare in terms of both knock tendency and engine performances like thermal efficiency, torque and combustion stability. Starting from the optimization of a single injection strategy, a split injection strategy is then evaluated. Under the present operating conditions, an optimum secondary injection timing of 100 CAD BTDC is found to have significant improvements on both the knock resistance and the overall engine performances. It should be noted that the present results indicate that the relationship between double injection and anti-knock performance is not monotonous. In addition, the double injection shows superior potential in improving fuel economy and power performance in contrast with the single injection thanks to a more stable combustion when a late injection timing is applied.

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Effects of the Multiple Injection Strategy on Combustion and Emission Characteristics of a Two-Stroke Marine Engine

Energies ◽

10.3390/en14206821 ◽

2021 ◽

Vol 14 (20) ◽

pp. 6821

Author(s):

Ju-Hwan Seol ◽

Van Chien Pham ◽

Won-Ju Lee

Keyword(s):

Single Injection ◽

Simulation Software ◽

Emission Characteristics ◽

Cylinder Pressure ◽

Multiple Injection ◽

Injection Strategy ◽

Marine Engine ◽

Injection Mode ◽

Double Injection ◽

Simulation Results

This paper presents research on the effects of the multiple injection strategies on the combustion and emission characteristics of a two-stroke heavy-duty marine engine at full load. The ANSYS FLUENT simulation software was used to conduct three-dimensional simulations of the combustion process and emission formations inside the engine cylinder in both single- and double-injection modes to analyze the in-cylinder pressure, temperature, and emission characteristics. The simulation results were then compared and showed good agreement with the measured values reported in the engine’s sea-trial technical reports. The simulation results showed reductions in the in-cylinder pressure and temperature peaks by 6.42% and 12.76%, while NO and soot emissions were reduced up to 24.16% and 68%, respectively, in the double-injection mode in comparison with the single-injection mode. However, the double-injection strategy increased the CO2 emission (7.58%) and ISFOC (23.55%) compared to the single-injection. These are negative effects of the double-injection strategy on the engine that the operators need to take into consideration. The results were in line with the literature reviews and would be good material for operators who want to reduce the engine exhaust gas emission in order to meet the stricter IMO emission regulations.

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Optimization of piston bowl and valve system in compression ignition engine fueled with gasoline/diesel/polyoxymethylene dimethyl ethers for high efficiency

International Journal of Engine Research ◽

10.1177/1468087419865384 ◽

2019 ◽

pp. 146808741986538

Author(s):

Bowen Li ◽

Haoye Liu ◽

Linjun Yu ◽

Zhi Wang ◽

Jianxin Wang

Keyword(s):

Heat Transfer ◽

Thermal Efficiency ◽

High Efficiency ◽

Compression Ignition ◽

Combustion Mode ◽

Compression Ignition Engine ◽

Valve System ◽

Percentage Points ◽

Polyoxymethylene Dimethyl Ethers ◽

Variable Valve

Polyoxymethylene dimethyl ethers, with excellent volatility and oxygen content of up to 49%, have great potential to improve engine performance and emission characteristics. In this study, experiments were carried out in a single-cylinder engine fueled with gasoline/diesel/polyoxymethylene dimethyl ethers blend fuel using multiple premixed compression ignition combustion mode along with engine optimization to exploit the high-efficiency potential. The thermal efficiency was increased by 9.4 percentage points after transforming the combustion mode from conventional diesel mode to gasoline/diesel/polyoxymethylene dimethyl ethers multiple premixed compression ignition mode. A fully variable valve system and a redesigned low-heat-transfer piston were used to further improve the thermal efficiency. The low-heat-transfer piston had a 15% lower area–volume ratio compared with the original ω-type piston. By replacing the original ω-type piston with the low-heat-transfer piston, the heat transfer loss was reduced by 2.29 percentage points and thus indicated thermal efficiency could be increased by 2.37 percentage points, which was up to 50.03%. On the basis of the low-heat-transfer piston, indicated thermal efficiency could be further increased to 51.09% with the application of fully variable valve system due to the longer ignition delay and more premixed combustion. At the same time, NOX emissions could be controlled below 0.4 g/kW·h using high exhaust gas recirculation ratio, which equaled the NOX emission limit of Euro VI standard. Although soot emissions could be increased due to weak turbulence and insufficient intake charge using the low-heat-transfer piston and fully variable valve system, it was still lower than those of the original diesel engines.

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Effect of Injection Strategies in Diesel/NG Direct-Injection Engines on the Combustion Process and Emissions under Low-Load Operating Conditions

Energies ◽

10.3390/en13040990 ◽

2020 ◽

Vol 13 (4) ◽

pp. 990 ◽

Cited By ~ 1

Author(s):

Jinze Li ◽

Longfei Deng ◽

Jianjun Guo ◽

Min Zhang ◽

Zhenyuan Zi ◽

...

Keyword(s):

Thermal Efficiency ◽

Direct Injection ◽

Combustion Process ◽

Combustion Efficiency ◽

Operating Conditions ◽

Diffusion Combustion ◽

Combustion Mode ◽

Low Load ◽

Hc Emissions ◽

Injection Strategies

The direct injection of natural gas (NG), which is an important research direction in the development of NG engines, has the potential to improve thermal efficiency and emissions. When NG engines operate in low-load conditions, combustion efficiency decreases and hydrocarbon (HC) emissions increase due to lean fuel mixtures and slow flame propagation speeds. The effect of two combustion modes (partially premixed compression ignition (PPCI) and high pressure direct injection (HPDI)) on combustion processes was investigated by CFD (Computational Fluid Dynamics), with a focus on different injection strategies. In the PPCI combustion mode, NG was injected early in the compression stroke and premixed with air, and then the pilot diesel was injected to cause ignition near the top dead center. This combustion mode produced a faster heat release rate, but the HC emissions were higher, and the combustion efficiency was lower. In the HPDI combustion mode, the diesel was injected first and ignited, and then the NG was injected into the flame. This combustion mode resulted in higher emissions of NOx and soot, with a diffusion combustion in the cylinder. HC emissions significantly decreased. Compared with PPCI combustion, HPDI had a higher thermal efficiency.

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Application of double-injection strategy on gasoline compression ignition engine under low load condition

Fuel ◽

10.1016/j.fuel.2017.04.107 ◽

2017 ◽

Vol 203 ◽

pp. 792-801 ◽

Cited By ~ 30

Author(s):

Donghoon Kim ◽

Choongsik Bae

Keyword(s):

Load Condition ◽

Compression Ignition ◽

Compression Ignition Engine ◽

Injection Strategy ◽

Double Injection ◽

Low Load

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Towards low emissions and high thermal efficiency of gasoline compression ignition engine under high loads by modulating the fuel reactivity and injection strategy

Science China Technological Sciences ◽

10.1007/s11431-019-1436-y ◽

2019 ◽

Vol 63 (1) ◽

pp. 96-104 ◽

Cited By ~ 1

Author(s):

ChenXu Jiang ◽

ZiLong Li ◽

Yong Qian ◽

XingCai Lu

Keyword(s):

Thermal Efficiency ◽

Compression Ignition ◽

Compression Ignition Engine ◽

Injection Strategy

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Improving the Thermal Efficiency of the Homogeneous Charge Compression Ignition Engine by Using Various Combustion Patterns

Energies ◽

10.3390/en11113002 ◽

2018 ◽

Vol 11 (11) ◽

pp. 3002 ◽

Cited By ~ 1

Author(s):

Yuh-Yih Wu ◽

James H. Wang ◽

Faizan Mushtaq Mir

Keyword(s):

Thermal Efficiency ◽

High Efficiency ◽

Homogeneous Charge Compression Ignition ◽

Combustion Engine ◽

Combustion Characteristics ◽

Compression Ignition ◽

Compression Ignition Engine ◽

Cycle Simulation ◽

Homogeneous Charge ◽

Wiebe Function

The efficiency of an internal combustion engine (ICE) is essential for automobiles and motorcycles. Several studies have demonstrated that the homogeneous charge compression ignition (HCCI) is a promising technology for realizing engines with high efficiency and low emissions. This study investigated the combustion characteristics of the HCCI using a 125 cc motorcycle engine with n-heptane fuel. The engine performance, combustion characteristics, and thermal efficiency were analyzed from experimental data. The results revealed that a leaner air–fuel mixture led to higher engine efficiency and output. The improvement of engine output is contradictory to the general trend. Energy balance analysis revealed that lower heat loss, due to the low cylinder gas temperature of lean combustion, contributed to higher efficiency. A double-Wiebe function provided excellent simulation of the mass fraction burned (MFB) of the HCCI. Air cycle simulation with the MFB, provided by the double-Wiebe function, was executed to investigate this phenomenon. The results indicated that a better combustion pattern led to higher thermal efficiency, and thus the engine output and thermal efficiency do not require a fast combustion rate in an HCCI engine. A better combustion pattern can be achieved by adjusting air–fuel ratio (AFR) and the rates of dual fuel and exhaust gas recirculation (EGR).

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Effects of split and single injection strategies on particle number emission and combustion of a GDI engine

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/0954407018759739 ◽

2018 ◽

Vol 233 (5) ◽

pp. 1100-1114 ◽

Cited By ~ 2

Author(s):

Fangxi Xie ◽

Wenliang Zheng ◽

Hong Chen ◽

Yu Liu ◽

Yan Su ◽

...

Keyword(s):

Fuel Consumption ◽

Particle Number ◽

Fuel Injection ◽

Single Injection ◽

Specific Fuel Consumption ◽

Injection Timing ◽

Brake Specific Fuel Consumption ◽

Split Injection ◽

Injection Strategy ◽

Injection Strategies

Influence of fuel injection parameters of the single and split injection strategies on combustion, performance and particle number emission had been investigated on a gasoline direct injection engine with stoichiometric mixture combustion under medium and low engine operating conditions. The test results showed that the optimal injection timing for single injection strategy was about 290–280 °CA BTDC, and an earlier or a later injection timing could lead to a deterioration of particle number emission. For split injection strategy, the injected parameters also needed to be optimized subtly in order to improve particle number emission. When the inappropriate injected parameters were adopted, particle number emission increased rather than decrease when compared with single injection strategy. Similar to single injection strategy, when the second injection timing of split injection strategy further retarded from 280 °CA BTDC, the particle number emission and brake-specific fuel consumption also started to deteriorate, and the in-cylinder combustion process was delayed and slowed. The optimal first injection timing was about 300 °CA BTDC. When the first injection timing was delayed to 280 °CA BTDC with the second injection timing being 260 °CA BTDC, the particle number emission increased and the shortened interval time between first and second fuel injection might have had a negative effect. The smaller difference of the fuel quantity between the first and the second injection was not good for the improvement of particle number emission and brake-specific fuel consumption, and the best injection proportion was 2:8. Overall, the engine particle number emission could be decreased to some extent, which could reach about 10–30%, by split injection strategy with optimal control parameters at medium and low engine loads.

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