Dependence of Ultra-High EGR and Low Temperature Diesel Combustion on Fuel Injection Conditions and Compression Ratio

2006 ◽  
Author(s):  
Hideyuki Ogawa ◽  
Tie Li ◽  
Noboru Miyamoto ◽  
Shingo Kido ◽  
Hejime Shimizu
Keyword(s):  
Low Temperature ◽  
Compression Ratio ◽  
Fuel Injection ◽  
Diesel Combustion

scholarly journals The Dependence of Ultra-High EGR and Low Oxygen Diesel Combustion on Fuel Injection and Compression Ratio

2006 ◽  
Vol 72 (714) ◽  
pp. 543-549 ◽  
Author(s):  
Hideyuki OGAWA ◽  
Tie LI ◽  
Shingo KIDO ◽  
Hajime SHIMIZU ◽  
Noboru MIYAMOTO
Keyword(s):  
Compression Ratio ◽  
Fuel Injection ◽  
Diesel Combustion ◽  
Low Oxygen

An Evaluation of Combustion and Emissions Performance With Low Cetane Naphtha Fuels in a Multi-Cylinder Heavy-Duty Diesel Engine

2015 ◽  
Author(s):  
Yu Zhang ◽  
Alexander Voice ◽  
Tom Tzanetakis ◽  
Michael Traver ◽  
David Cleary
Keyword(s):  
High Temperature ◽  
Diesel Engine ◽  
Low Temperature ◽  
Compression Ratio ◽  
Fuel Injection ◽  
Fuel Efficiency ◽  
Injection Pressure ◽  
Heavy Duty ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel

Future projections in global transportation fuel use show a demand shift towards diesel and away from gasoline. At the same time greenhouse gas regulations will drive higher vehicle fuel efficiency and lower well-to-wheel CO2 production. Naphtha, a contributor to the gasoline stream and requiring less processing at the refinery level, is an attractive candidate to mitigate this demand shift while lowering the overall greenhouse gas impact. In this work, low cetane and high volatility gasoline-like fuels have shown potential to achieve high fuel efficiency with low engine-out emissions in a production commercial vehicle engine. This study investigates the combustion and emissions performance of two low cetane naphtha fuels (Naphtha 1: RON59; Naphtha 2: RON69) and one ultra-low sulfur diesel (ULSD) in a model year (MY) 2013, six-cylinder, heavy-duty diesel engine. The engine is equipped with a single-stage variable geometry turbocharger (VGT) and a fuel injection system that is capable of 2500 bar fuel injection pressure. The engine has a stock geometric compression ratio of 18.9. To date, most studies in this area have been conducted using single-cylinder research engines. Aramco aims to better understand the implications on hardware and software design in a multi-cylinder engine with a production engine air system. Engine testing was focused on the Heavy-Duty Supplemental Emissions Test (SET) “B” speed over a load sweep from 5 to 15 bar BMEP. At each operating point, NOx sweeps were conducted over wide ranges (e.g., 0.2 → 3 g/hp-hr) to understand the implications of fuel reactivity as well as other properties on combustion behavior under both high temperature mixing-controlled combustion and low temperature premixed combustion. At 10–15 bar BMEP, mixing-controlled combustion dominates the engine combustion process. Under a compression ratio of 18.9, cylinder pressure and temperature are sufficiently high to suppress the reactivity (cetane number) difference between ULSD and the low cetane naphtha fuels. As a result, the three test fuels showed similar ignition delay under high temperature and pressure conditions. Nevertheless, naphtha fuels still exhibited notable soot reduction compared to ULSD. Under mixing-controlled combustion, this is likely due to their lower aromatic content and higher volatility. At 10 bar BMEP, Naphtha 1 generated less soot than Naphtha 2 since it contains less aromatics and is more volatile. When operated at light load, in a less reactive thermal environment, the lower reactivity naphtha fuels led to longer ignition delays than ULSD. As a result, the soot benefit of naphtha fuels was enhanced. Overall, naphtha fuels and ULSD had similar fuel efficiency. Utilizing the soot benefit of the naphtha fuels, engine-out NOx was calibrated from the production level of 3–4 g/hp-hr down to 2–2.5 g/hp-hr over the twelve non-idle SET steady-state modes. At this reduced NOx level, naphtha fuels were still able to maintain a soot advantage over ULSD and remain “soot-free” (smoke ≤ 0.2 FSN) while achieving diesel-equivalent fuel efficiency. Finally, partially premixed compression ignition (PPCI) low temperature combustion (LTC) operation (NOx ≤ 0.2 g/hp-hr; smoke ≤ 0.2 FSN) was achieved with both of the naphtha fuels at 5 bar BMEP through a late injection approach with high injection pressure. Under high EGR dilution, Naphtha 2 showed an appreciably longer ignition delay than Naphtha 1, resulting in a soot reduction benefit. Early injection PPCI operation cannot be attained with the stock engine compression ratio due to excessive pressure rise rates. Although the late injection PPCI operation offered a significant NOx benefit over mixing-controlled combustion operation, it led to lower fuel efficiency with undesirably late combustion phasing. This points the research towards a lower engine compression ratio and an air system upgrade to promote high efficiency PPCI LTC operation.

Experimental Study of Low Temperature Diesel Combustion Sensitivity to Engine Operating Parameters

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
G. P. McTaggart-Cowan ◽  
S. Cong ◽  
C. P. Garner ◽  
E. Wahab ◽  
M. Peckham
Keyword(s):  
Low Temperature ◽  
Engine Speed ◽  
Fuel Injection ◽  
Fractional Factorial ◽  
Combustion Stability ◽  
Small Scale ◽  
Operating Parameters ◽  
Diesel Combustion ◽  
Injection Quantity ◽  
Charge Temperature

This work elucidated which engine operating parameters have the greatest influence on Low temperature diesel combustion (LTC) and emissions. Key parameters were selected and evaluated at low and intermediate speed and load conditions using fractional factorial and Taguchi orthogonal experimental designs. The variations investigated were: about ± 5% in EGR rate, fuel injection quantity and engine speed respectively; and ± 10 °C in intake charge temperature. The half-fractional factorial results showed that the interactions among these parameters were negligible for a specific load/speed point. The Taguchi orthogonal method could be used as an efficient DoE tool for studying the multi-parameter ‘small-scale transients’ that a diesel engine would be likely to encounter when operating in LTC modes. LTC showed the most significant sensitivity to EGR rate variations, where an increase from 60% to 63% in EGR rate doubled THC and CO emissions and reduced combustion stability. LTC was also sensitive to the fuel injection quantity with an increase in injected mass lowering the overall oxygen-fuel ratio and thereby increasing THC and CO emissions. These two parameters influenced the oxygen concentration in the intake charge; which was identified to be a decisive parameter for the LTC combustion and emissions. Intake charge temperature affected the total charge quantity trapped in the cylinder and showed noticeable influence on CO emissions for the low speed intermediate load condition. Variations in engine speed showed a negligible influence on the LTC combustion processes and emissions.

Analysis of Mixture Formation and Flame Development of Diesel Combustion Using a Rapid Compression Machine and Optical Visualization Technique

2013 ◽  
Vol 315 ◽  
pp. 293-298 ◽  
Author(s):  
Amir Khalid ◽  
Bukhari Manshoor
Keyword(s):  
Fuel Injection ◽  
Injection Pressure ◽  
Exhaust Emissions ◽  
Combustion Characteristics ◽  
Diesel Combustion ◽  
Rapid Compression Machine ◽  
Mixture Formation ◽  
Optical Visualization ◽  
Flame Development ◽  
Rapid Compression

Mixture formation plays as a key element on burning process that strongly affects the exhaust emissions such as nitrogen oxide (NOx) and Particulate Matter (PM). The reductions of emissions can be achieved with improvement throughout the mixing of fuel and air behavior. Measurements were made in an optically-accessible rapid compression machine (RCM) with intended to simulate the actual diesel combustion related phenomena. The diesel combustion was simulated with the RCM which is equipped with the Denso single-shot common-rail fuel injection system, capable of a maximum injection pressure up to 160MPa. Diesel engine compression process could be reproduced within the wide range of ambient temperature, ambient density, swirl velocity, equivalence ratio and fuel injection pressure. The mixture formation and combustion images were captured by the high speed camera. Analysis of combustion characteristics and observations of optical visualization of images reveal that the mixture formation exhibit influences to the ignition process and flame development. Therefore, the examination of the first stage of mixture formation is very important consideration due to the fuel-air premixing process linked with the combustion characteristics. Furthermore, the observation of a systematic control of mixture formation with experimental apparatus enables us to achieve considerable improvements of combustion process and would present the information for fundamental understanding in terms of reduced fuel consumption and exhaust emissions.

Sign in / Sign up

Export Citation Format

Share Document