Numerical Assessment of Additive Manufacturing-Enabled Innovative Piston Bowl Design for a Light-Duty Diesel Engine Achieving Ultra-Low Engine-Out Soot Emissions

For copious levels of exhaust gas recirculation (EGR) (>30 %), oxides of nitrogen (NOx) emissions can be reduced from Euro V to Euro VI regulated levels at the expense of fuel economy and soot emissions. The Lifted-Flame Concept (LFC) has been demonstrated by several researchers to be successful in reducing NOx, while minimizing soot emissions and impact to fuel economy. By simultaneously applying increased EGR and fuel pressure the LFC extends the lift-off length of a diffusion flame and enhances fuel-air entrainment leading to improved fuel and oxygen utilization. When combined with advanced turbocharging and EGR systems the LFC applied to a modern light duty (LD) diesel engine can result in improved fuel economy and lower soot emissions and shows good potential for meeting low soot engine-out targets. In the proposed paper a computational study was conducted using a multi-dimensional engine model. A modified 3D CFD KIVA code with detailed chemistry solver was used to model the diesel fuel spray, droplet breakup, vaporization, mixing, auto-ignition and subsequent heat release and emissions. The model uses inputs from 1D Amesim electro-hydraulic solver to generate the rate of injection (ROI) profile to raise pressure of 1800 bar to 2500 bar as well as to include a simulated post-injection. A 1D model using GT-Power was developed and utilized to provide air system boundary conditions for the 3D CFD model. Post-processing optimization was conducted using Matlab to identify minimum fuel economy and soot emissions for the study of several parameters. The objective of the study was to demonstrate Euro VI emissions levels on a 3.2 L LD diesel engine without NOx aftertreatment and minimal impact to fuel economy using the lifted flame concept. The engine-out NOx emission level was targeted at 0.4 g/kWh and the soot levels were targeted at 0.2 g/kWh assuming diesel particulate filter would be used for after-treatment. The results of the computational study successfully demonstrate the potential of the lifted flame concept to meet Euro VI without the use of NOx aftertreatment technology.

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Numerical Assessment of the CO2 Reduction Potential of Variable Valve Actuation on a Light Duty Diesel Engine

10.4271/2018-37-0006 ◽

2018 ◽

Author(s):

Andrea Piano ◽

Federico Millo ◽

Davide Di Nunno ◽

Alessandro Gallone

Keyword(s):

Diesel Engine ◽

Reduction Potential ◽

Co2 Reduction ◽

Variable Valve Actuation ◽

Light Duty ◽

Numerical Assessment ◽

Variable Valve ◽

Valve Actuation

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Effects of Mixing and Chemical Parameters on Homogeneous Charge Induced Ignition Combustion Based on a Light-Duty Diesel Engine with Ultra-Low NOx and Soot Emissions and High Thermal Efficiency

10.4271/2013-01-0914 ◽

2013 ◽

Cited By ~ 6

Author(s):

Wenbin Yu ◽

Zhiqiang Kang ◽

Wei Guo ◽

Jichun Liu ◽

Weibo Zhao ◽

...

Keyword(s):

Diesel Engine ◽

Thermal Efficiency ◽

Chemical Parameters ◽

Light Duty ◽

Soot Emissions ◽

Induced Ignition ◽

Homogeneous Charge

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The Effects of Spray Angle and Piston Bowl Shape on Diesel Engine Soot Emissions Using 3-D CFD Simulation

10.4271/2005-01-2117 ◽

2005 ◽

Cited By ~ 9

Author(s):

Jaeman Lim ◽

Kyoungdoug Min

Keyword(s):

Diesel Engine ◽

Cfd Simulation ◽

Spray Angle ◽

Piston Bowl ◽

Soot Emissions

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High Efficiency Two-Valve DI Diesel Engine for Off-Road Application Complying With Upcoming Emission Limits

ASME 2012 Internal Combustion Engine Division Spring Technical Conference ◽

10.1115/ices2012-81217 ◽

2012 ◽

Cited By ~ 2

Author(s):

Gian Marco Bianchi ◽

Giulio Cazzoli ◽

Claudio Forte ◽

Marco Costa ◽

Marcello Oliva

Keyword(s):

Diesel Engine ◽

Flow Field ◽

High Efficiency ◽

Nox Emission ◽

Main Concern ◽

Swirl Ratio ◽

Emission Standard ◽

Piston Bowl ◽

Soot Emissions ◽

Emission Limits

Nowadays, environmental concerns are posing a great challenge to DI Diesel engines. Increasingly tightening emission limits require a higher attention on combustion efficiency. In this scenario, computational fluid-dynamics can prove its power guaranteeing a deeper understanding of mixture formation process and combustion. A high efficiency Diesel engine can be developed only mastering all the parameters that can affect the combustion and, therefore, NOx and soot emissions. In this work, the development of an engine in order to fulfill Tier 4i emission standard will be presented. Originally, the engine was a two-valve engine supplied with a DPF. Since no SCR aftertreatment is supplied, NOx emission target are achieved through external exhaust gas recirculation and retarding the start of injection. In order to fulfill Tier 4i emissions, the main concern is on soot emission and, thus, the combustion chamber has been re-designed, through CFD simulations, leading to a better interaction between the flow field, the fuel spray and the piston bowl geometry. Particularly, through intake phase simulations, performed with the CFD code Fire v2009 v3, different intake ducts, with different swirl ratio, have been simulated in order to provide a flow field as realistic as possible for the combustion simulations. Through combustion process simulations, performed with the CFD code Kiva, by varying different parameters the interaction between the swirl flow field, generated by the intake duct, the reverse squish motion, and motions aerodynamically generated by spray has been investigated leading to the definition of a new engine lay-out. The study shows how, given the need of retarded injection for limiting NOx emission, the decrease of swirl ratio, when combined with a proper piston bowl design, allows a significant decrease of soot emissions and the achievement of Tier 4i emission standard.

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