An Investigation of Injection Rate Controlled Heat Release of Low Cetane Fuels in a Direct Injected Diesel Engine

1990 ◽  
Author(s):  
Bradlee J. Stroia ◽  
Duane L. Abata
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Injection Rate ◽  
Rate Controlled

Flame Speeds of Low-Cetane Fuels in a Diesel Engine

1991 ◽  
Vol 113 (3) ◽  
pp. 456-463 ◽  
Author(s):  
B. J. Stroia ◽  
D. L. Abata
Keyword(s):  
Theoretical Model ◽  
Diesel Engine ◽  
Heat Release ◽  
High Speed ◽  
Fuel Injection ◽  
Injection Rate ◽  
Initial Stage ◽  
Main Injection ◽  
Pilot Fuel ◽  
Rate Controlled

A theoretical and experimental investigation of the flame speeds of low-cetane fuels during the initial stage of heat release in a Diesel engine is described. This information is important for developing a fundamental background in the understanding of fuel injection rate-controlled heat release in a Diesel engine. In this study, a theoretical model based on droplet size, turbulent intensity, and equivalence ratio was developed for the flame propagation through a fuel droplet/air matrix. The results of the theoretical model were compared to experimental high-speed photographs of flame growth in a Diesel engine. For successful injection rate controlled heat release to occur using pilot injdection, the model determined that the combustion zone due to a pilot fuel spray must flow to a distance of at least 30 orifice diameters from the nozzle tip before the main injection event can take place. Results of the model were verified by experiment for the two limiting cases of X/D less than 30 and X/D greater than 30. As expected, rate-controlled heat release was to achieved for the case of X/D less than 30. However, for the case of X/D greater than 30, the main fuel injectin ignited upon injection into the cylinder, and heat release was controlled by rate of injection.

scholarly journals Effects of Injection Rate Profile on Combustion Process and Emissions in a Diesel Engine

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Fuqiang Bai ◽  
Zuowei Zhang ◽  
Yongchen Du ◽  
Fan Zhang ◽  
Zhijun Peng
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Combustion Process ◽  
Injection Rate ◽  
Injection System ◽  
Nox Emissions ◽  
Release Process ◽  
Common Rail Injection System ◽  
Soot Emissions ◽  
Rate Profile

When multi-injection is implemented in diesel engine via high pressure common rail injection system, changed interval between injection pulses can induce variation of injection rate profile for sequential injection pulse, though other control parameters are the same. Variations of injection rate shape which influence the air-fuel mixing and combustion process will be important for designing injection strategy. In this research, CFD numerical simulations using KIVA-3V were conducted for examining the effects of injection rate shape on diesel combustion and emissions. After the model was validated by experimental results, five different shapes (including rectangle, slope, triangle, trapezoid, and wedge) of injection rate profiles were investigated. Modeling results demonstrate that injection rate shape can have obvious influence on heat release process and heat release traces which cause different combustion process and emissions. It is observed that the baseline, rectangle (flat), shape of injection rate can have better balance between NOx and soot emissions than the other investigated shapes. As wedge shape brings about the lowest NOx emissions due to retarded heat release, it produces the highest soot emissions among the five shapes. Trapezoid shape has the lowest soot emissions, while its NOx is not the highest one. The highest NOx emissions were produced by triangle shape due to higher peak injection rate.

Effect of Biodiesel-Ethanol Blended Fuel Spray Characteristics on the Reduction of Exhaust Emissions in a Common-Rail Diesel Engine

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Seung Hyun Yoon ◽  
Su Han Park ◽  
Hyun Kyu Suh ◽  
Chang Sik Lee
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Diesel Fuel ◽  
Injection Rate ◽  
Combustion Characteristics ◽  
Common Rail ◽  
Fuel Spray ◽  
Blended Fuel ◽  
Ethanol Blends ◽  
Conventional Diesel Fuel

An experimental investigation was performed to analyze the effects of biodiesel-ethanol blended fuel spray on the combustion, and exhaust emission characteristics in a single cylinder common-rail diesel engine. In order to analyze the macroscopic and microscopic characteristics of biodiesel blended fuel spray, parameters, such as injection rate, droplet diameter, and spray tip penetration, were measured using an injection rate meter system, spray visualization, and droplet measuring system. Also, measurements of combustion, exhaust emissions, and size distributions of particulate matter were carried out under various engine operating conditions for biodiesel-ethanol blends and the results were compared with those of conventional diesel fuel. In this investigation, the measured results of biodiesel-ethanol blended fuel show that the Sauter mean diameter decreased with the increase of relative velocity between the injected fuel and the ambient gas. Comparing the combustion characteristics of diesel fuel and biodiesel-ethanol blended fuels, both diesel and blended fuel show similar trends of combustion pressure and rate of heat release. However, the combustion of biodiesel-ethanol blends indicated lower combustion characteristics, such as combustion pressures and heat release rates, than those of diesel fuel because of its lower heating value. In the case of exhaust gas recirculation, the indicated specific NOx(ISNOx) and soot concentration results showed lower emissions compared with those of conventional diesel fuel.

Computational Analysis of a Diesel Engine Autoignition, Combustion, and Emissions Using Injection Rate Shapes

2013 ◽  
Author(s):  
Amit Shrestha ◽  
Ziliang Zheng ◽  
Tamer Badawy ◽  
Naeim A. Henein
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Computational Analysis ◽  
Injection Rate ◽  
Gas Pressure ◽  
Operating Conditions ◽  
Rate Of Heat Release

Injection rate shaping is a method used to control the instantaneous mass flow rate of the fuel during an injection event. The rate at which the fuel is delivered affects the composition of the combustible mixture and its distribution in the combustion chamber, thereby has an impact on the combustion process in the diesel engine. This paper investigates the effects of five different types of injection rate shapes on diesel engine autoignition, combustion, and engine-out emission trends using a three-dimensional computational simulation approach. For this purpose, an n-heptane fuel model is utilized. Initially, a tophat rate-shape, characterized by the constant mass flow rate of the fuel, is assumed to represent the actual injection profile of an actual engine. Then, in order to develop sufficient confidence in the simulation predictions, this assumption together with the calibrated CFD models are validated by reproducing the cylinder gas pressure, the rate of heat release, and engine-out emissions trends for two sets of engine operating conditions. Later, using all the rate shapes the investigation is conducted for one test point considering two different cases of fuel injection: Case 1 - same SOI and duration of injection (DOI), and Case 2 - same combustion phasing and DOI. The results obtained from the computational analysis show that the injection rate shape affects the autoignition, combustion, and emissions of a diesel engine. It is observed that the rate shapes, characterized by high injection rates at the beginning of the injection event, enhance the formation of negative temperature coefficient (NTC) regime. Therefore, the mole fractions of different species are determined during the NTC regime in order to examine the processes relevant to the formation of the NTC regimes for these rate shapes. Further, for the same SOI and DOI case, significant differences in the ignition delays between each rate shapes are observed. The maximum deviation of the ignition delay from the reference tophat is found to be 37%. Furthermore, the paper highlights the differences in the cylinder gas pressure, gas temperature, and rate of heat release due to different fuel delivery rates of different rate shapes. Finally, the comparison of the engine-out emissions for different rate shapes for both the cases of injection are presented and discussed in detail.

scholarly journals The Effect of RME-1-Butanol Blends on Combustion, Performance and Emission of a Direct Injection Diesel Engine

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2941
Author(s):  
Wojciech Tutak ◽  
Arkadiusz Jamrozik ◽  
Karol Grab-Rogaliński
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Direct Injection ◽  
Specific Energy Consumption ◽  
Combustion Process ◽  
Constant Load ◽  
Combustion Stability ◽  
Performance And Emission ◽  
Energy Share ◽  
The Stability

The main objective of this study was assessment of the performance, emissions and combustion characteristics of a diesel engine using RME–1-butanol blends. In assessing the combustion process, great importance was placed on evaluating the stability of this process. Not only were the typical COVIMEP indicators assessed, but also the non-burnability of the characteristic combustion stages: ignition delay, time of 50% heat release and the end of combustion. The evaluation of the combustion process based on the analysis of heat release. The tests carried out on a 1-cylinder diesel engine operating at a constant load. Research and evaluation of the combustion process of a mixture of RME and 1-butanol carried out for the entire range of shares of both fuels up to 90% of 1-butanol energetic fraction. The participation of butanol in combustion process with RME increased the in-cylinder peak pressure and the heat release rate. With the increase in the share of butanol there was noted a decrease in specific energy consumption and an increase in engine efficiency. The share of butanol improved the combustion stability. There was also an increase in NOx emissions and decrease in CO and soot emissions. The engine can be power by blend up to 80% energy share of butanol.

A phenomenological combustion analysis of a dual-fuel natural-gas diesel engine

2016 ◽  
Vol 231 (1) ◽  
pp. 66-83 ◽  
Author(s):  
Shuonan Xu ◽  
David Anderson ◽  
Mark Hoffman ◽  
Robert Prucka ◽  
Zoran Filipi
Keyword(s):  
Diesel Engine ◽  
Natural Gas ◽  
Heat Release ◽  
Diesel Fuel ◽  
Fuel Injection ◽  
Dual Fuel ◽  
Injection Timing ◽  
Heavy Duty ◽  
Engine System ◽  
Wiebe Function

Energy security concerns and an abundant supply of natural gas in the USA provide the impetus for engine designers to consider alternative gaseous fuels in the existing engines. The dual-fuel natural-gas diesel engine concept is attractive because of the minimal design changes, the ability to preserve a high compression ratio of the baseline diesel, and the lack of range anxiety. However, the increased complexity of a dual-fuel engine poses challenges, including the knock limit at a high load, the combustion instability at a low load, and the transient response of an engine with directly injected diesel fuel and port fuel injection of compressed natural gas upstream of the intake manifold. Predictive simulations of the complete engine system are an invaluable tool for investigations of these conditions and development of dual-fuel control strategies. This paper presents the development of a phenomenological combustion model of a heavy-duty dual-fuel engine, aided by insights from experimental data. Heat release analysis is carried out first, using the cylinder pressure data acquired with both diesel-only and dual-fuel (diesel and natural gas) combustion over a wide operating range. A diesel injection timing correlation based on the injector solenoid valve pulse widths is developed, enabling the diesel fuel start of injection to be detected without extra sensors on the fuel injection cam. The experimental heat release trends are obtained with a hybrid triple-Wiebe function for both diesel-only operation and dual-fuel operation. The ignition delay period of dual-fuel operation is examined and estimated with a predictive correlation using the concept of a pseudo-diesel equivalence ratio. A four-stage combustion mechanism is discussed, and it is shown that a triple-Wiebe function has the ability to represent all stages of dual-fuel combustion. This creates a critical building block for modeling a heavy-duty dual-fuel turbocharged engine system.

A Spray-Droplet Model for Diesel Combustion

1969 ◽  
Vol 184 (10) ◽  
pp. 28-35 ◽  
Author(s):  
J. Shipinski ◽  
P. S. Myers ◽  
O. A. Uyehara
Keyword(s):  
Experimental Data ◽  
Diesel Engine ◽  
Heat Release ◽  
Engine Speed ◽  
Chamber Pressure ◽  
Gas Temperature ◽  
Single Droplet ◽  
Burning Rates ◽  
Burning Model ◽  
The One

A spray-burning model (based on single-droplet theory) for heat release in a diesel engine is presented. Comparison of computations using this model and experimental data from an operating diesel engine indicate that heat release rates are not adequately represented by single-droplet burning rates. A new concept is proposed, i.e. a burning coefficient for a fuel spray. Comparisons between computations and experimental data indicate that the numerical value of this coefficient is nearly independent of engine speed and combustion-chamber pressure. However, the instantaneous value of the spray burning coefficient is approximately proportional to the instantaneous mass-averaged cylinder gas temperature to the one-third power.

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