Split Injection Spray Development, Mixture Formation, and Combustion Processes in a Diesel Engine Piston Cavity: Rig Test and Real Engine Results

2018 ◽  
Author(s):  
Tomoya Shiwaku ◽  
Shintaro Yasaki ◽  
Keiya Nishida ◽  
Youichi Ogata ◽  
Mamoru Suzuki ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Mixture Formation ◽  
Split Injection ◽  
Engine Piston ◽  
Combustion Processes

Effects of dwell time of split injection on mixture formation and combustion processes of diesel spray

2021 ◽  
pp. 095440702110536
Author(s):  
Samir Chandra Ray ◽  
Jaeheun Kim ◽  
Scinichi Kakami ◽  
Keiya Nishida ◽  
Youichi Ogata
Keyword(s):  
Dwell Time ◽  
Equivalence Ratio ◽  
Diesel Spray ◽  
Spray Combustion ◽  
Mixture Formation ◽  
Split Injection ◽  
Lean Mixture ◽  
Rich Mixture ◽  
The Rich ◽  
Combustion Processes

The effects of dwell time on the mixture formation and combustion processes of diesel spray are investigated experimentally. A commercial multihole injector with a 0.123 mm hole diameter is used to inject the fuel. The injection procedure is either a single or split injection with different dwell times, whereas the total amount of injected fuel mass is 5.0 mg per hole. Three dwell times are selected, that is, 0.12, 0.32 and 0.54 ms, with a split ratio of 7:3 based on previous findings. The vapour phase is observed, and the mixture formation pertaining to the equivalence ratio is analysed using the tracer laser absorption scattering (LAS) technique. A high-speed video camera is used to visualise the spray combustion flame luminosity, whereas a two-colour pyrometer system is used to evaluate the soot concentrations and flame temperature. An analysis of the mixture formation based on the spray evaporating condition reveals a more concentrated area of the rich mixture within a 0.32 ms dwell time. In the shortest dwell time of 0.12 ms, the equivalence ratio distribution decreases uniformly from the rich mixture region to the lean mixture region. In the case involving a shorter dwell time, a suitable position for the second injection around the boundaries of the first injection is obtained by smoothly growing the lean mixture and avoiding the large zone of the rich mixture. Therefore, the shortest dwell time is acceptable for mixture formation, considering the overall distribution of the equivalence ratios. Spray combustion analysis results show that the soot formation rate of the single injection and 0.32 ms dwell time case is high and decreases quickly, implying a rapid reduction in the high amount of soot. Consequently, 0.12 ms can be considered the optimal dwell time due to the ignition delay and relatively low soot emission afforded.

Effect of split injection on mixture formation and combustion processes of diesel spray injected into two-dimensional piston cavity

2017 ◽  
Vol 232 (8) ◽  
pp. 1121-1136 ◽  
Author(s):  
Kang Yang ◽  
Hirotaka Yamakawa ◽  
Keiya Nishida ◽  
Youichi Ogata ◽  
Yusuke Nishioka
Keyword(s):  
Soot Formation ◽  
Single Injection ◽  
Injection Pressure ◽  
Diesel Spray ◽  
Two Dimensional ◽  
Mixture Formation ◽  
Split Injection ◽  
Main Injection ◽  
Combustion Processes ◽  
Injection Strategies

The objective of this study is to obtain an enhanced understanding of the effect of split injection on mixture formation and combustion processes of diesel spray. A two-dimensional (2D) piston cavity of the same shape as that used in a small-bore diesel engine was employed to form the impinging spray flame. The fuel was injected into a high pressure, high temperature constant volume vessel through a single-hole nozzle with a hole diameter of 0.11 mm. The injection process comprised a pre-injection followed by the main injection. The main injection was carried out either as a single injection of injection pressure 100 MPa (Pre+S100), or by two types of split injection of injection pressure 160 MPa. The latter two types were defined by mass fraction ratios 1:1 and 3:1 (Pre+D160_1-1, Pre+D160_3-1). In order to observe the spray mixture formation process, the tracer laser absorption scattering (LAS) techique was adopted. Tracer LAS fuel with 97.5 vol% of n-tridecane and 2.5 vol% of 1-methylnaphthalene (α-MN) was employed. The spatial distributions of the vapor and liquid phases and the spray mixture formation characteristics in the 2D piston cavity for the three injection strategies were investigated. The diesel spray combustion and soot formation processes were studied using a high-speed video camera. The flame structure and soot formation process were examined using two-color pyrometry. The experimental results revealed that the split-injection vapor distribution was significantly more homogeneous than that of the single injection. The main injection fuel caught up with the pre-injection fuel and provided the spray tip with substantial additional momentum, enabling it to advance further. A high soot concentration and low temperatures appeared near the cavity wall region under the three injection strategies. The soot reduction rate for split injection was higher than that for single injection. The second main injection caught up with the previous injection’s flame, which deteriorated the combustion and resulted in higher soot generation. The effect of split injection on the process of soot evolution finished at the same time as that of single injection.

Microcharacterization of heavy-duty diesel engine piston deposits

2002 ◽  
Vol 33 (3) ◽  
pp. 259-268 ◽  
Author(s):  
G. C. Smith ◽  
A. B. Hopwood ◽  
K. J. Titchener
Keyword(s):  
Diesel Engine ◽  
Heavy Duty ◽  
Engine Piston ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel

The analyses of frictional losses and thermal stresses in a diesel engine piston coated with different thicknesses of thermal barrier films using co-simulation method

2021 ◽  
pp. 146808742110656
Author(s):  
Fatma Bayata ◽  
Cengiz Yildiz
Keyword(s):  
Diesel Engine ◽  
Coating Thickness ◽  
Thermal Stresses ◽  
Equivalent Stress ◽  
Simulation Method ◽  
Thermal Barrier ◽  
Barrier Films ◽  
Engine Piston ◽  
Frictional Performance ◽  
Artificial Neural Network Ann

This study comparatively presents the thermal and mechanical effects of different Thermal Barrier Coatings (TBCs) and their thicknesses on the performance of aluminum diesel engine piston by combining Finite Element Analyses (FEA) and Artificial Neural Network (ANN) methods. The piston structure of MWM TbRHS 518S indirect injection six-cylinder diesel engine was modeled. The clustered TBCs (NiCrAlY–Gd2Zr2O7, NiCrAlY–MgO-ZrO2, NiCrAl–Yttria Partially Stabilized Zirconia (YPSZ), and NiCrAlY–La2Zr2O7) were implemented to the related surface of aluminum alloy piston and then static, thermal, and transient structural FEA were conducted for each model. Based on both of the temperature and equivalent stress distributions, NiCrAlY–Gd2Zr2O7 coated model displayed the best performance. Additionally, the effects of top coating thicknesses of TBCs were investigated in the range of 0.1–1.0 mm with 0.1 mm increments in FEAs. The thermally effective top coating thickness was predicted as 0.95 mm for the selected TBC using ANN method. Then the effects of coating thickness on frictional performance were revealed by generating transient structural FE models and utilizing stribeck diagram. The uncoated and 0.95 mm NiCrAlY–Gd2Zr2O7 coated models were adjusted as transient and the related crank angle – dependent in-cylinder combustion pressure data was implemented. The friction force was reduced by at least 15% in NiCrAlY–Gd2Zr2O7 coated model.

scholarly journals Mechanism of Emission Reduction in HSDI Diesel Engine: Split Injection

2015 ◽  
Vol 09 (2) ◽  
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Temporal Distribution ◽  
Reaction Rates ◽  
Chemical Mechanism ◽  
Symmetric Model ◽  
Diesel Combustion ◽  
Split Injection ◽  
Engine Combustion ◽  
Experimental Values

In order to meet the stringent emission standards significant efforts have been imparted to the research and development of cleaner IC engines. Diesel combustion and the formation of pollutants are directly influenced by spatial and temporal distribution of the fuel injected. The development and validation of computational fluid dynamics (CFD) models for diesel engine combustion and emissions is described. The complexity of diesel combustion requires simulation with many complex interacting sub models in order to have a success in improving the performance and to reduce the emissions. In the present work an attempt has been made to develop a multidimensional axe-symmetric model for CI engine combustion and emissions. Later simulations have been carried out using split injection for single, double and three pulses (split injection) for which commercial validation tool FLUENT was used for simulation. The tool solves basic governing equations of fluid flow that is continuity, momentum, species transport and energy equation. Using finite volume method turbulence was modeled by using RNG K-ɛ model. Injection was modeled using La Grangian approach and reaction was modeled using non premixed combustion which considers the effects of turbulence and detailed chemical mechanism into account to model the reaction rates. The specific heats were approximated using piecewise polynomials. Subsequently the simulated results have been validated with the existing experimental values. The peak pressure obtained by simulation for single and double is 10% higher than to that of experimental value. Whereas for triple injections 5% higher than to that of experimental value. For quadruple injection the pressure has been decreased by 10% when compared to triple injection.NOX have been decreased in simulation for single, double and triple injections by 15%, 28% and 20%.For quadruple injection NOX were reduced in quadruple injection by 20% to that of triple injection. The simulated value of soot for single, double and triple injections are 12%, 22% and 12% lesser than the experimental values. For quadruple injection the soot levels were almost negligible. The simulated heat release rates for single, double and triple were reduced by 12%, 18% and 11%. For quadruple injection heat release is reduced same as to that of triple injection.

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