A Predictive Ignition Delay Correlation Under Steady-State and Transient Operation of a Direct Injection Diesel Engine

2003 ◽  
Vol 125 (2) ◽  
pp. 450-457 ◽  
Author(s):  
D. N. Assanis ◽  
Z. S. Filipi ◽  
S. B. Fiveland ◽  
M. Syrimis
Keyword(s):  
Steady State ◽  
Diesel Engine ◽  
Ignition Delay ◽  
Direct Injection ◽  
Thermodynamic Simulation ◽  
Injection Pressure ◽  
Transient Operation ◽  
Load Spectrum ◽  
Two Phase ◽  
Transient Conditions

Available correlations for the ignition delay in pulsating, turbulent, two-phase, reacting mixtures found in a diesel engine often have limited predictive ability, especially under transient conditions. This study focuses on the development of an ignition delay correlation, based on engine data, which is suitable for predictions under both steady-state and transient conditions. Ignition delay measurements were taken on a heavy-duty diesel engine across the engine speed/load spectrum, under steady-state and transient operation. The dynamic start of injection was calculated by using a skip-fire technique to determine the dynamic needle lift pressure from a measured injection pressure profile. The dynamic start of combustion was determined from the second derivative of measured cylinder pressure. The inferred ignition delay measurements were correlated using a modified Arrhenius expression to account for variations in fuel/air composition during transients. The correlation has been compared against a number of available correlations under steady-state conditions. In addition, comparisons between measurements and predictions under transient conditions are made using the extended thermodynamic simulation framework of Assanis and Heywood. It is concluded that the proposed correlation provides better predictive capability under both steady-state and transient operation.

scholarly journals Effect of Fuel Cetane Numbers on Reducing the Ignition Delay Period and Exhaust Emissions from DI Diesel Engine

2020 ◽  
Vol 15 ◽  
Keyword(s):  
Diesel Engine ◽  
Ignition Delay ◽  
Direct Injection ◽  
Cetane Number ◽  
Injection Pressure ◽  
Exhaust Emissions ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Engine Torque ◽  
Di Diesel Engine

In this present study a theoretical investigation is used to examine the effect of different fuel cetane numbers (CNs) on reducing the ignition delay and exhaust emissions from diesel engine at certain operating conditions. The operating conditions for such diesel engine include compression ratios, engine speeds and intake pressures and temperatures. For this purpose, the fuels with 40 and 50 CN were tested in a four cycle, four cylinders direct injection (DI) diesel engine. Theoretical analyses were conducted for the standard injection pressures (150 bars); the exhaust emissions were tested at engine speeds from 4500 min-1 to 1000 min-1 at full engine load. The results showed that, at all operating conditions, the ignition delay decreases as the cetane number, compression ratio, engine speed, intake pressure and temperature are increased so that combustion efficiency is improved. Also the exhaust emissions NOX, SO2 and CO are reduced when the fuel CN is increased from 40 to 50 for the standard injection pressure (150 bars). Increases in engine torque and power output were observed when the CN is increased.

Applying the Representative Interactive Flamelet Model to Evaluate the Potential Effect of Wall Heat Transfer on Soot Emissions in a Small-Bore Direct-Injection Diesel Engine

2002 ◽  
Vol 124 (4) ◽  
pp. 1042-1052 ◽  
Author(s):  
C. Hergart ◽  
N. Peters
Keyword(s):  
Diesel Engine ◽  
Combustion Chamber ◽  
Direct Injection ◽  
Particle Growth ◽  
Potential Effect ◽  
Two Phase ◽  
Flamelet Model ◽  
Detailed Chemistry ◽  
Direct Injection Diesel Engine ◽  
Soot Emissions

Capturing the physics related to the processes occurring in the two-phase flow of a direct-injection diesel engine requires a highly sophisticated modeling approach. The representative interactive flamelet (RIF) model has gained widespread attention owing to its ability of correctly describing ignition, combustion, and pollutant formation phenomena. This is achieved by incorporating very detailed chemistry for the gas phase as well as for the soot particle growth and oxidation, without imposing any significant computational penalty. This study addresses the part load soot underprediction of the model, which has been observed in previous investigations. By assigning flamelets, which are exposed to the walls of the combustion chamber, with heat losses calculated in a computational fluid dynamics (CFD) code, predictions of the soot emissions in a small-bore direct-injection diesel engine are substationally improved. It is concluded that the experimentally observed emissions of soot may have their origin in flame quenching at the relatively cold combustion chamber walls.

Experimental Evaluation of Compression Ignition Engine Fueled with Cashew Nut Shell Liquid Diesel Blend with the Effect of Various Injection Pressures

2015 ◽  
Vol 787 ◽  
pp. 717-721
Author(s):  
Sangeetha Krishnamoorthy ◽  
K. Rajan ◽  
K.R. Senthil Kumar ◽  
M. Prabhahar
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Injection Pressure ◽  
Cashew Nut Shell Liquid ◽  
Compression Ignition Engine ◽  
Brake Thermal Efficiency ◽  
Performance And Emission ◽  
Full Load ◽  
Cashew Nut ◽  
Cashew Nut Shell

This paper investigates the performance and emission characteristics of 20% cashew nut shell liquid (CNSL)-diesel blend (B20) in a direct injection diesel engine. The cashew nut shell liquid was prepared by pyrolysis method. The test was conducted with various nozzle opening pressures like 200 bar, 225 bar and 250 bar at different loads between no load to full load. The results showed that the brake thermal efficiency was increased by 2.54% for B20 with 225 bar at full load. The CO and smoke emissions were decreased by 50% and 14% respectively and the NOx emission were decreased slightly with 225 bar injection pressure compared with 200 bar and 250 bar at full load. On the whole, it is concluded that the B20 CNSL blend can be effectively used as a fuel for diesel engine with 225 bar injection pressure without any modifications.

Effect of Swirl Ratio and Injection Pressure on Autoignition, Combustion and Emissions in a High Speed Direct Injection Diesel Engine Fuelled With Biodiesel (B-20)

2009 ◽  
Author(s):  
Vinay Nagaraju ◽  
Mufaddel Dahodwala ◽  
Kaushik Acharya ◽  
Walter Bryzik ◽  
Naeim A. Henein
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Direct Injection ◽  
Injection Pressure ◽  
Combustible Mixture ◽  
Injection System ◽  
Ignition Process ◽  
Swirl Ratio ◽  
Mixture Formation ◽  
Physical And Chemical

Biodiesel has different physical and chemical properties than ultra low sulfur diesel fuel (ULSD). The low volatility of biodiesel is expected to affect the physical processes, mainly fuel evaporation and combustible mixture formation. The higher cetane number of biodiesel is expected to affect the rates of the chemical reactions. The combination of these two fuel properties has an impact on the auto ignition process, subsequently combustion and engine out emissions. Applying different swirl ratios and injection pressures affect both the physical and chemical processes. The focus of this paper is to investigate the effect of varying the swirl ratio and injection pressure in a single-cylinder research diesel engine using a blend of biodiesel and ULSD fuel. The engine is a High Speed Direct Injection (HSDI) equipped with a common rail injection system, EGR system and a swirl control mechanism. The engine is operated under simulated turbocharged conditions with 3 bar Indicated Mean Effective Pressure (IMEP) at 1500 rpm, using 100% ULSD and a blend of 20% biodiesel and 80% ULSD fuel. The biodiesel is developed from soy bean oil. A detailed analysis of the apparent rate of heat release (ARHR) is made to determine the role of the biodiesel component of B-20 in the combustible mixture formation, autoignition process, premixed, mixing controlled and diffusion controlled combustion fractions. The results explain the factors that cause an increase or a drop in NOx emissions reported in the literature when using biodiesel.

Diesel engine control optimization for transient operation with lean/rich switches

2003 ◽  
Vol 4 (3) ◽  
pp. 219-231 ◽  
Author(s):  
N. P. Kyrtatos ◽  
E. I. Tzanos ◽  
C. I. Papadopoulos
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Optimization Procedure ◽  
Combustion Model ◽  
Transient Operation ◽  
Simulation Code ◽  
Engine Operation ◽  
Control Optimization ◽  
Management Schemes ◽  
Engine Components

Transient operation of a direct injection heavy duty (DI HD) diesel engine equipped with an NOx storage catalyst (NSC) was simulated using a ‘virtual powerplant’ simulation code with a zero-dimensional multizone combustion model. For the regeneration of the NSC the engine is required to work with lean/rich operation switches, which necessitates advanced engine management schemes for the fuelling, throttle and turbocharger wastegate. An optimization procedure, using the simulation model, resulted in a proposed schedule for the control of the various engine components involved in such engine operation.

scholarly journals Effects of injection pressure on cavitation and spray in marine diesel engine

2016 ◽  
Vol 9 (3) ◽  
pp. 186-198 ◽  
Author(s):  
Fei Yan ◽  
Yuchen Du ◽  
Lihui Wang ◽  
Wenxian Tang ◽  
Jian Zhang ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Bubble Dynamics ◽  
Pressure Fluctuations ◽  
Injection Pressure ◽  
Spray Angle ◽  
Marine Diesel Engine ◽  
Sauter Mean Diameter ◽  
Two Phase ◽  
Marine Diesel ◽  
Single Bubble Dynamics

Numerical simulation of the cavitation and spray in a marine diesel engine is performed to investigate the effects of injection pressure on the cavitation flow and spray characteristics in the marine diesel engine, which in turn influence atomization and combustion in the cylinder. A two-phase flow model combined with single bubble dynamics and a droplet break-up model are used to simulate cavitation and spray, respectively, and the results are compared to the experimental data. With increasing injection pressure, the pressure fluctuations inside the nozzle become more intense. The spray penetration is proportional to time at the beginning of injection. Higher injection pressure increases the spray angle. In addition, massive structures on spray edge can return to the spray body, whereas the massive structures on the spray head remain unchanged throughout its lifetime. Each additional 20 MPa of injection pressure reduces the Sauter mean diameter by approximately 9%.

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