Numerical Analysis of Engine Efficiency by Pilot and Main Injection Timing Optimization through 1D Modeling of Diesel Engine

With the universal utilization of the common-rail injection system in automotive diesel engines, the multistage injection strategies have become typical approaches to satisfy the increasingly stringent emission regulations, and especially the post injection has received considerable attention as an effective way for reducing the smoke emissions. Normally the post injection is applied in combination with the pilot injection to restrain the NOx emissions, smoke emissions, and combustion noise simultaneously, and the pilot injection condition affects the combustion process of the main injection and might affect the smoke reduction effect of the post injection. Thus this study aims at obtaining the post injection strategy to reduce smoke emissions in a diesel engine, where post injection is employed in combination with pilot injection. The experiments were performed using a single-cylinder diesel engine under various conditions of pilot and post injection with a constant load at an IMEP of 1.01 MPa, fixed speed of 1500 rpm, and NOx emissions concentration of 150 ± 5 ppm that was maintained by adjusting the EGR ratio. The injection pressure was set at 90 MPa at first, and then it was varied to 125 MPa to evaluate the effects of post injection on the smoke reduction in the case of higher injection pressure. The experimental results show that small post injection quantity with a short interval from the end of main injection causes less smoke emissions. And larger pilot injection quantity and later pilot injection timing lead to higher smoke emissions. And then, to explore and interpret the smoke emissions tendencies with varying pilot and post injection conditions, the experimental results of three-stage injection conditions were compared to those of two reference cases, which only included the pilot and main injection, and the interaction between main spray flames and post sprays was applied for analysis. Based on the comparative analysis, the larger smoke reduction effect of post injection was observed with the larger pilot injection quantity, while it is not greatly influenced by pilot injection timing. In addition, the smoke emissions can be reduced considerably by increasing the injection pressure, however the smoke reduction effect of post injection was attenuated. And all of these tendencies were able to be interpreted by considering the intensity variation of the interaction between main spray flames and post sprays.

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Application of CFD, Taguchi Method, and ANOVA Technique to Optimize Combustion and Emissions in a Light Duty Diesel Engine

Mathematical Problems in Engineering ◽

10.1155/2014/502902 ◽

2014 ◽

Vol 2014 ◽

pp. 1-9 ◽

Cited By ~ 6

Author(s):

Senlin Xiao ◽

Wanchen Sun ◽

Jiakun Du ◽

Guoliang Li

Keyword(s):

Diesel Engine ◽

Taguchi Method ◽

Fuel Consumption ◽

Soot Formation ◽

Dynamics Simulation ◽

Injection Timing ◽

Light Duty ◽

Study Results ◽

Main Injection ◽

Pilot Fuel

Some previous research results have shown that EGR (exhaust gas recirculation) rate, pilot fuel quantity, and main injection timing closely associated with engine emissions and fuel consumption. In order to understand the combined effect of EGR rate, pilot fuel quantity, and main injection timing on theNOx(oxides of nitrogen), soot, and ISFC (indicated specific fuel consumption), in this study, CFD (computational fluid dynamics) simulation together with the Taguchi method and the ANOVA (analysis of variance) technique was applied as an effective research tool. At first, simulation model on combustion and emissions of a light duty diesel engine at original baseline condition was developed and the model was validated by test. At last, a confirmation experiment with the best combination of factors and levels was implemented. The study results indicated that EGR is the most influencing factor onNOx. In case of soot emission and ISFC, the greatest influence parameter is main injection timing. For all objectives, pilot fuel quantity is an insignificant factor. Furthermore, the engine with optimized combination reduces by at least 70% forNOx, 20% in soot formation, and 1% for ISFC, in contrast to original baseline engine.

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The influence of the hydrogen injection timing on the IC engine working cycle

Thermal Science ◽

10.2298/tsci190816346g ◽

2020 ◽

pp. 346-346

Author(s):

Ivan Grujic ◽

Jovan Doric ◽

Oday Abdullah ◽

Nadica Stojanovic ◽

Aleksandar Davinic

Keyword(s):

Diesel Engine ◽

Pressure Rise ◽

Maximum Pressure ◽

Injection Timing ◽

Ic Engine ◽

Engine Efficiency ◽

Working Cycle ◽

Spark Timing ◽

Ic Engines ◽

Combustion Speed

From an ecological aspect, the hydrogen has all properties to be a very good fuel for IC engines. However the high combustion speed, as well as the possibility of backfire, is inconvenient properties of port injection. In this paper, the influence of the injection timing on the IC engine working cycle parameters (pressure and temperature) was investigated deeply. The investigation, of the injection timing influence on the IC engine working cycle parameters, was performed numerically by application of ANSYS software. It was observed the geometry of the real engine with added pre chamber, in order of layer mixture formation and pressure damping, because of high combustion speed. The results are presented for four cases with different injection timing and the same spark timing. By earlier injection, the time for mixing rise as well as the possibility of homogenization and uniform mixture creation, in pre chamber and cylinder. This claim it is confirmed on the basis of obtaining pressure and pressure rise gradient, which are growing with earlier injection, because of hydrogen combustion characteristics in stoichiometric mixture. The higher pressures as well as the surface under the diagram are positive from the aspect of the engine efficiency. However, with the earlier injection, the values of the pressure rise gradient are higher than for the classic diesel engine. This means that this phenomena can cause brutal engine work from the aspect of mechanical stresses. However the value of the maximum pressure is smaller than this in a diesel engine, this is due to added pre chamber, which has decreased the compression ratio.

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Effects of fuel injection parameters on premixed charge compression ignition combustion and emission characteristics in a medium-duty compression ignition diesel engine

International Journal of Engine Research ◽

10.1177/1468087419867014 ◽

2019 ◽

pp. 146808741986701 ◽

Cited By ~ 1

Author(s):

Santiago Molina ◽

Antonio García ◽

Javier Monsalve-Serrano ◽

David Villalta

Keyword(s):

Diesel Engine ◽

Fuel Injection ◽

Transport Sector ◽

Injection Timing ◽

Compression Ignition ◽

Injection Strategy ◽

Low Load ◽

Main Injection ◽

Compression Ignition Combustion ◽

The Impact

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 means of a methodology based on the evaluation of a merit function. The results suggest that the best injection strategy for the low-load premixed charge compression ignition operating condition investigated implies using a high injection pressure and a triple-injection event with a delayed main injection with almost 15% of the total fuel mass injected.

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Effect of Injection System Parameters on Performance and Emission Characteristics of a Small Single Cylinder Diesel Engine

International Journal of Automotive and Mechanical Engineering ◽

10.15282/ijame.18.2.2021.17.0673 ◽

2021 ◽

Vol 18 (2) ◽

Author(s):

D.K. Dond ◽

N.P. Gulhane

Keyword(s):

Diesel Engine ◽

Fuel Injection ◽

Direct Injection ◽

Common Rail ◽

Injection System ◽

Injection Timing ◽

Emission Characteristics ◽

Performance And Emission ◽

System Parameters ◽

Main Injection

Limited fossil fuel reservoir capacity and pollution caused by them is the big problem in front of researchers. In the present paper, an attempt was made to find a solution to the same. The conventional fuel injection system was retrofitted with a simple version of the common rail direct injection system for the small diesel engine. Further, the effect of injection system parameters was observed on the performance and emission characteristics of the retrofitted common rail direct injection diesel engine. The parameters such as injection pressure, the start of pilot injection timing, the start of main injection timing and quantity of percentage fuel injection during the pilot and main injection period were considered for experimental investigation. It was observed that all the evaluated parameters were found vital for improving the engine’s performance and emission characteristics. The retrofitted common rail direct injection system shows an average 7% rise in brake thermal efficiency with economic, specific fuel consumption. At the same time, much more reduction in hydrocarbon, carbon monoxide and smoke opacity with a penalty of a slight increase in nitrogen oxides.

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Effects of Pre-Injection on Combustion Characteristics of a Single-Cylinder Diesel Engine

Volume 3: Combustion Science and Engineering ◽

10.1115/imece2009-10493 ◽

2009 ◽

Cited By ~ 4

Author(s):

M. Mittal ◽

G. Zhu ◽

T. Stuecken ◽

H. J. Schock

Keyword(s):

Diesel Engine ◽

Combustion Process ◽

Load Condition ◽

Combustion Characteristics ◽

Combustion Noise ◽

Injection Timing ◽

Single Cylinder ◽

Multiple Injections ◽

Main Injection ◽

Load Conditions

Multiple injections used for diesel engines, especially pre- and post-injections, have the potential to reduce combustion noise and emissions with improved engine performance. This paper outlines the combustion characteristics of a single-cylinder diesel engine with multiple injections. The effects of pre-injection (multi-injection) on combustion characteristics are presented in a single-cylinder diesel engine at different engine speeds and load conditions. A common rail fuel system with a solenoid injector, driven by a peak and hold circuit, is used in this work. This enables us to control the number of injections, fuel injection timing and duration, and the fuel rail pressure that can be used to optimize the engine combustion process (e.g., eliminate engine knock). Mass fraction burned and burn durations are determined by analyzing the measured in-cylinder pressure data. Results are compared with the cases when no pre-injection was used, i.e. only main injection, at the same engine speeds and load conditions. In each study, different cases are considered with the variation in main injection timing. It is found that at full-load condition and lower engine speeds pre-injection is an effective method to alter the engine burn rate and hence to eliminate knock.

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Assessment on the consequences of injection strategies on combustion process and particle size distributions in Euro VI medium-duty diesel engine

International Journal of Engine Research ◽

10.1177/1468087419865652 ◽

2019 ◽

Vol 21 (4) ◽

pp. 683-697 ◽

Cited By ~ 2

Author(s):

Vicente Bermúdez ◽

Antonio García ◽

David Villalta ◽

Lian Soto

Keyword(s):

Particle Size ◽

Diesel Engine ◽

Size Distribution ◽

Particle Concentration ◽

Combustion Process ◽

Injection Pressure ◽

Injection Timing ◽

Injection Parameters ◽

Main Injection ◽

Injection Strategies

Although there are already several works where the influence of injection parameters on exhaust emissions, and specifically on particulate matter emissions, in diesel engines has been evaluated, the diversity in the results that can be found in the literature indicates the need to carry out new experiments that can provide more information about the influence of these parameters on modern diesel engines. This study intends to be placed within this scientific framework, hence a parametric study was carried out based on the independent modification of the main injection timing and the injection pressure with respect to the nominal conditions of a new Euro VI direct injection diesel engine. Four steady-state operation points of the engine map were chosen: 25% load and 950 r/min, 50% load and 1500 r/min, 75% load and 2000 r/min and 100% load and 2200 r/min, where in each of these operation points, the variations of the injection parameters in the study on the combustion process and its consequent impact on the particle size distribution, including an analysis of the geometric mean diameter values, were evaluated. The results showed that the different injection strategies adopted, despite not significantly affecting the engine efficiency, did cause a significant impact on particle number emissions. At the low load operation, the size distribution showed a bimodal structure, and as the main injection timing was delayed and the injection pressure was decreased, the nucleation-mode particle concentration decreased, while the accumulation-mode particle concentration increased. In addition, at medium load, the nucleation-mode particle emission decreased considerably while the accumulation-mode particle emission increased, and this increase was much greater with the main injection timing delay and the injection pressure reduction. Similar behavior was observed at high load, but with a much more prominent pattern.

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Experimental Investigation of Thermal Load in High Speed Direct Injection Diesel Engine Under the Control of Various Engine Performance Parameters

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4001767 ◽

2010 ◽

Vol 133 (3) ◽

Cited By ~ 2

Author(s):

Jeonghoon Lee

Keyword(s):

Diesel Engine ◽

Thermal Load ◽

High Speed ◽

Direct Injection ◽

Injection Timing ◽

Pilot Injection ◽

Performance Parameters ◽

Full Load ◽

Main Injection ◽

Vibration Noise

Multiple injection strategies are being widely utilized to reduce the vibration, noise, and particle emission in diesel engines. A considerable amount of research related to attempts to increase the maximum power and to reduce vibration, noise, and particulate matters has been done. However, investigations of various performance parameters in terms of the thermal load in high speed direct injection engines are rarely to be found despite the fact that the relationship between these parameters and the reliability of the engine is important for mass production. Hence, the thermal load imposed on the cylinder head and cylinder block of a four-cylinder diesel engine was investigated under the most severe test conditions, at the rated speed and with a full load, by changing the performance parameters such as the main injection timing, the fuel pressure in the common rail, the boost pressure, the exhaust gas recirculation, the fuel quantity of the pilot injection, the timing of the pilot injection, the fuel quantity of the postinjection, and the timing of postinjection. Experimental results showed that the main injection timing among other parameters was the parameter that influenced the thermal load most at the rated engine speed and under a full load condition.

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A Study on a Passenger Car Diesel Engine Fueled with Butanol-Diesel Blend under Typical Operating Condition

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.190-191.1345 ◽

2012 ◽

Vol 190-191 ◽

pp. 1345-1350

Author(s):

Ting Bo Zhou ◽

Zhi Yu Han ◽

Zheng Chen ◽

Biao Du ◽

Yun Liu

Keyword(s):

Diesel Engine ◽

Injection Timing ◽

Passenger Car ◽

Blend Ratio ◽

Operating Condition ◽

Injection Quantity ◽

Combustion Phase ◽

Main Injection ◽

Typical Operating Condition ◽

Burn Rate

The effects of butanol-diesel blending ratio, injecting timing and pilot injection quantity on combustion and emissions were experimentally investigated for a passenger car diesel engine. The results showed that under the typical operating condition of 2000r/min engine speed and 0.2MPa BMEP engine load, the engine’s combustion phase retarded, the peak combustion pressure and maximum in-cylinder mean temperature decreasing with the delay of the main injection timing using both the neat diesel and diesel-butanol blends. And the engine smoke level increased, while the NOx and CO emissions decreased. However, at the same main injection timing, with the increase of the butanol in the blends, the ignition delay of the combustion prolonged, the burn rate and brake specific fuel consumption increased, NOx and soot emissions decreased, and HC and CO emissions increased, while the peak in-cylinder pressure was slightly influenced. The results of this study indicate that the selection of the butanol-diesel blend ratio and injection timing should consider the engineering balances among the engine’s fuel economy and emissions.

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