Effects of injection pressure on the NOx and PM emission control of diesel engine: A review under the aspect of PCCI combustion condition (original) (raw)
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STUDY OF THE EFFECT OF FUEL INJECTION PRESSURE ON DIESEL ENGINE PERFORMANCE AND EMISSION - A REVIEW
Diesel engines combustion quality is based on the formation of fuel-air mixture. Enormous efforts have made to reduce the harmful diesel engine emissions. High engine noise, Particulate matter (PM) and NOx production are the results of improper combustion process and considered as the major constraints. The performance and emission characteristics of diesel engines depend on many parameters. Precise control over the fuel injection process is one of the most important factors and plays a very important role in combustion to increase the engine performance with minimal exhaust emission. The injection system must satisfy high pressure capability, injection pressure control, flexible timing control, and injection rate control. The purpose of this study is to find the performance and exhaust emission of diesel engines by implementing high injection pressure. Present paper is more concentrated on the optimization of high pressure injection to reduce particulate matter (PM), NOx and fuel consumption with increased engine power.
SAE Technical Paper Series, 2007
Homogeneous Charge Compression Ignition (HCCI) combustion is a combustion concept which offers simultaneous reductions in both NO x and soot emissions from internal combustion engines. In light of increasingly stringent diesel emissions limits, research efforts have been invested into HCCI combustion as an alternative to conventional diesel combustion. This paper reviews the implementation of HCCI combustion in direct injection diesel engines using early, multiple and late injection strategies. Governing factors in HCCI operations such as injector characteristics, injection pressure, piston bowl geometry, compression ratio, intake charge temperature, exhaust gas recirculation (EGR) and supercharging or turbocharging are discussed in this review. The effects of design and operating parameters on HCCI diesel emissions, particularly NO x and soot, are also investigated. For each of these parameters, the theories are discussed in conjunction with comparative evaluation of studies reported in the specialised literature.
Energy, 2017
In this study, an advanced combustion concept 'premixed charge compression ignition' (PCCI) has been explored for diesel engines. PCCI combustion is a single-stage combustion process, in which a large fraction of fuel burns in premixed combustion phase resulting in relatively lower in-cylinder temperatures compared to compression ignition (CI) engine combustion. However at high loads, PCCI combustion results in severe knocking and higher oxides of nitrogen (NOx) emissions. This limits the applicability of this combustion concept to medium loads. This limitation of PCCI combustion can be resolved by altering in-cylinder pressure-temperature history at the time of fuel injection. This can be also be resolved by deploying suitable split fuel injection strategy and exhaust gas recirculation (EGR), which control combustion events such as start of combustion (SoC) and combustion phasing, leading to lower knocking and NOx emissions. To investigate the effects of various split injection strategy and EGR on PCCI combustion, engine experiments were conducted at different start of main injection (SoMI) timings (12, 16, 20 and 24° bTDC), start of pilot injection (SoPI) timings (30, 35 and 40° bTDC) and EGR rates (0, 15 and 30%). This study also included detailed
Thermal Science, 2015
The use of diesel engines for vehicle has been increasing recently due to its higher thermal efficiency and lower CO2 emission level. However, in the case of diesel engine, NOx increases in a high temperature combustion region and particulate matter is generated in a fuel rich region. Therefore, the technique of PCCI (premixed charge compression ignition) is often studied to get the peak combustion temperature down and to make a better air-fuel mixing. However it also has got a limited operating range and lower engine power produced by the wall wetting and the difficulty of the ignition timing control. In this research, the effect of injection strategies on the injected fuel behavior, combustion and emission characteristics in a PCCI engine were investigated to find out the optimal conditions for fuel injection, and then ethanol blended diesel fuel was used to control the ignition timing. As a result, the combustion pressures and ROHR (rate of heat release) of the blended fuel becam...
International Journal of Vehicle Design, 2012
Homogenous charge compression ignition (HCCI) cases are compared for improvements on the combustion chamber design of the engine to achieve near zero particulate matter (PM) and NOx emissions. Therefore combustion simulations of the engine have been performed to fi nd out emission generation in the cylinder. The interaction of air motion with high-pressure fuel spray has also been analyzed. Finally, a comparison has been made considering the performance of the engine for various confi gurations such as compression ratio, injection timing, and cone angle. The results are widely in agreement qualitatively with the previous similar experimental and computational studies in the literature.
International Journal of Engine Research, 2019
From the different power plants, the compression ignition diesel engines are considered the best alternative to be used in the transport sector due to its high efficiency. However, the current emission standards impose drastic reductions for the main pollutants, that is, NO x and soot, emitted by this type of engines. To accomplish with these restrictions, alternative combustion concepts as the premixed charge compression ignition are being investigated nowadays. The objective of this work is to evaluate the impact of different fuel injection strategies on the combustion performance and engine-out emissions of the premixed charge compression ignition combustion regime. For that, experimental measurements were carried out in a single-cylinder medium-duty compression ignition diesel engine at low-load operation. Different engine parameters as the injection pattern timing, main injection timing and main injection fuel quantity were sweep. The best injection strategy was determined by m...
2010
Homogeneous Charge Compression Ignition (HCCI) combustion is a combustion concept which offers simultaneous reductions in both NOx and soot emissions from internal combustion engines. In light of increasingly stringent diesel emissions limits, research efforts have been invested into HCCI combustion as an alternative to conventional diesel combustion. This paper reviews the implementation of HCCI combustion in direct injection diesel engines using early, multiple and late injection strategies. Governing factors in HCCI operations such as injector characteristics, injection pressure, piston bowl geometry, compression ratio, intake charge temperature, exhaust gas recirculation (EGR) and supercharging or turbocharging are discussed in this review. The effects of design and operating parameters on HCCI diesel emissions, particularly NOx and soot, are also investigated. For each of these parameters, the theories are discussed in conjunction with comparative evaluation of studies reported in the specialised literature.
In diesel engines, fuels that are more resistant to autoignition allow more time for mixing before combustion occurs and help reduce NOx and smoke. The fuel is injected near but before TDC in order to ensure in-cycle control over combustion phasing through injection timing and must not be fully premixed with air as in HCCI combustion. The present work considers the effects of fuel autoignition quality, volatility and aromatic content on this type of engine operation. A single-cylinder light-duty compression ignition engine is run on six very different fuels at different speeds, loads and EGR levels using a single injection. Even a fuel with very high aromatic level (~75%) and in the diesel boiling range can be run to get low NOx (< 0.4 g/kWh) and low smoke (FSN <0.1) if its cetane number is low enough. In contrast, at the same operating conditions, even if the fuel contains no aromatics or sulphur and is volatile but has high cetane, it cannot be run to get low NOx and low smoke simultaneously. Moreover, if the combustion phasing and delay are matched for any two fuels at a given condition, their emissions behaviour is also matched regardless of the differences in volatility and composition demonstrating that the autoignition resistance of the fuel is the most important fuel property when the injection is completed before combustion starts. The paper will also discuss strategies to address other issues that arise in this type of combustion such as high pressure rise rates at high loads and high CO and HC emissions.
Sensitivity of combustion noise and NOx and soot emissions to pilot injection in PCCI Diesel engines
Applied Energy, 2013
Diesel engines are the most commonly used internal combustion engines nowadays, especially in European transportation. This preference is due to their low consumption and acceptable driveability and comfort. However, the main disadvantages of traditional direct injection Diesel engines are their high levels of noise, nitrogen oxides (NO x) and soot emissions, and the usage of fossil fuels. In order to tackle the problem of high emission levels, new combustion concepts have been recently developed. A good example is the premixed charge compression ignition (PCCI) combustion, a strategy in which early injections are used, causing a burning process in which more fuel is burned in premixed conditions, which affects combustion noise. The use of a pilot injection has become an effective tool for reducing combustion noise. The main objective of this paper is to analyze experimentally the pollutant emissions, combustion noise, and performance of a Diesel engine operating under PCCI combustion with the use of a pilot injection. In addition, a novel methodology, based on the decomposition of the in-cylinder pressure signal, was used for combustion noise analysis. The results show that while the PCCI combustion has potential to reduce significantly the NO x and soot emission levels, compared to conventional Diesel combustion strategy, combustion noise continues to be a critical issue for the implementation of this new combustion concept in passenger cars.
Traktory i sel hozmashiny, 2020
The paper presents the simulation result of the influence of the ratio of the diameter of the combustion chamber Dкс to its depth hкс and boost pressure рк on the characteristics of a 1ChN 12/13 single-cylinder engine with an injection pressure of 300 MPa at a crankshaft speed of 1400 min-1. The simulation was performed with Dкс/hкс from 3,4 to 10,0, and рк from 0,15 to 0,45 MPa. The results show that the engine achieves the best performance, nitrogen oxides NOx in the exhaust gases decreases at Dкс/hкс = (7,8-10), and the pressure рк from 0,25 to 0,35 MPa. At рк = 0,35 MPa, Dкс/hкс = 10, the indicated power increases by 7,1 %. NOx reduces by 68 % but soot, CO, HC increase 4,5, 9,5, and 2,2 times, respectively. The results also show the impact of the boost pressure on spray characteristics. The boost pressure increases, the penetration, and the tip velocity decrease, but the spray angle changes a little. While the combustion chamber diameter changes, the penetration, and the spray a...