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

2012 ◽  
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.

A Computational Investigation of Piston Bowl Geometry and Injector Spray Pattern Effects on Gasoline Compression Ignition in a Heavy-Duty Diesel Engine

2019 ◽  
Author(s):  
Yu Zhang ◽  
Yuanjiang Pei ◽  
Meng Tang ◽  
Michael Traver
Keyword(s):  
Diesel Engine ◽  
Fuel Efficiency ◽  
Compression Ignition ◽  
Swirl Ratio ◽  
Heavy Duty ◽  
Load Range ◽  
Spray Pattern ◽  
Piston Bowl ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel

Abstract This study computationally investigates the potential of utilizing gasoline compression ignition (GCI) in a heavy-duty diesel engine to address a future ultra-low tailpipe NOx standard of 0.027 g/kWh while achieving high fuel efficiency. By conducting closed-cycle, full-geometry, 3-D computational fluid dynamics (CFD) combustion simulations, the effects of piston bowl geometry, injector spray pattern, and swirl ratio (SR) were investigated for a market gasoline. The simulations were performed at 1375 rpm over a load range from 5 to 15 bar BMEP. The engine compression ratio (CR) was increased from 15.7 used in previous work to 16.5 for this study. Two piston bowl concepts were studied with Design 1 attained by simply scaling from the baseline 15.7 CR piston bowl, and Design 2 exploring a wider and shallower combustion chamber design. The simulation results predicted that through a combination of the wider and shallower piston bowl design, a 14-hole injector spray pattern, and a swirl ratio of 1, Design 2 would lead to a 2–7% indicated specific fuel consumption (ISFC) improvement over the baseline by reducing the spray-wall interactions and lowering the in-cylinder heat transfer loss. Design 1 (10-hole and SR2) showed a more moderate ISFC reduction of 1–4% by increasing CR and the number of nozzle holes. The predicted fuel efficiency benefit of Design 2 was found to be more pronounced at low to medium loads.

Strategies to Meet US 1994/95 Diesel Engine Federal Emission Legislation for HSDI diesel Engine Powered Vehicles

1992 ◽  
Vol 206 (1) ◽  
pp. 47-54 ◽  
Author(s):  
L Bürgler ◽  
P L Herzog ◽  
P Zelenka
Keyword(s):  
Diesel Engine ◽  
Development Strategy ◽  
Central Position ◽  
Piston Bowl ◽  
Denox Catalysts ◽  
Main Emphasis ◽  
Hsdi Diesel Engine ◽  
Emission Limits ◽  
Technological Strategies ◽  
Emission Legislation

The forthcoming US passenger car and light-duty truck emission limits are currently the most stringent ones worldwide. The paper discusses which type of diesel engine has the best chance of fulfilling those requirements and what development strategy has to be followed. A comparative analysis between IDI and DI diesel engines shows the potential of the HSDI diesel engine to meet NOx/particulates limits of 0.4/0.08 g/min while maintaining its fuel economy advantage. Appropriate technological strategies are outlined. Besides the well-known technologies such as central position of injector and piston bowl, multi-valve cylinder head, inlet port swirl control etc., main emphasis is placed on the optimization of mixture preparation using fuel systems with variable injection rates as well as oxidation and DENOX catalysts.

Flow Field Measurements inside a Piston Bowl of a Heavy-Duty Diesel Engine

2011 ◽  
Author(s):  
Harri Hillamo ◽  
Teemu Anttinen ◽  
Ulf Aronsson ◽  
Clément Chartier ◽  
Oivind Andersson ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Flow Field ◽  
Field Measurements ◽  
Heavy Duty ◽  
Piston Bowl ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel

Effect of Piston Bowl Shape and Swirl Ratio on Engine Heat Transfer in a Light-Duty Diesel Engine

2014 ◽  
Author(s):  
Helgi Skuli Fridriksson ◽  
Martin Tuner ◽  
Oivind Andersson ◽  
Bengt Sunden ◽  
Hakan Persson ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Diesel Engine ◽  
Swirl Ratio ◽  
Piston Bowl ◽  
Light Duty

Numerical Simulation Study of the Influence of Structural Parameters of Combustion Chamber on In-Cylinder Flow Field of Diesel Engine

2013 ◽  
Vol 860-863 ◽  
pp. 1729-1732
Author(s):  
Guo Cheng Li ◽  
Ping Sun ◽  
Peng Hu
Keyword(s):  
Diesel Engine ◽  
Flow Field ◽  
Combustion Chamber ◽  
Structural Parameters ◽  
Volume Ratio ◽  
Initial Boundary ◽  
Swirl Flow ◽  
Swirl Ratio ◽  
Depth Ratio ◽  
Cylinder Flow

Based on the entity model of the type 4B26 diesel engine, calculated by CFD FIRE and combined with the software BOOST for the initial boundary conditions, the influence of combustion chamber structural parameters, such as boss height, surface-volume ratio and diameter-depth ratio of combustion chamber, on in-cylinder flow field of diesel engine was investigated. The results show that the influence of the boss height on flow field in the cylinder and the transient swirl ratio is obvious, and increasing the boss height is beneficial to urge the formation of mixture rapidly. Reducing the surface-volume ratio is beneficial for improving the maximum transient swirl ratio, and the air strength maintains well also, but has little influence to the retentivity of the swirl intensity. Meanwhile, reducing the diameter-depth ratio does not only improves the air flow movement strengthen in the combustion chamber, but also enhances the maximum transient swirl ratio, and the retentivity of swirl flow movement is satisfying.

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