Visualizations of combustion and emissions characteristics in a light-duty diesel engine with achieved premixed low temperature combustion

2015 ◽  
Vol 16 (2) ◽  
pp. 201-209 ◽  
Author(s):  
H. Jia ◽  
B. Yin ◽  
J. Wang ◽  
L. Chen
Keyword(s):  
Diesel Engine ◽  
Low Temperature ◽  
Low Temperature Combustion ◽  
Light Duty ◽  
Temperature Combustion ◽  
Premixed Low Temperature Combustion

Comparison of Filter Smoke Number and Elemental Carbon Mass From Partially Premixed Low Temperature Combustion in a Direct-Injection Diesel Engine

2011 ◽  
Vol 133 (10) ◽  
Author(s):  
William F. Northrop ◽  
Stanislav V. Bohac ◽  
Jo-Yu Chin ◽  
Dennis N. Assanis
Keyword(s):  
Diesel Engine ◽  
Low Temperature ◽  
Elemental Carbon ◽  
Direct Injection ◽  
Low Temperature Combustion ◽  
Soot Mass ◽  
Temperature Combustion ◽  
Carbon Mass ◽  
Partially Premixed ◽  
Premixed Low Temperature Combustion

Partially premixed low temperature combustion (LTC) is an established advanced engine strategy that enables the simultaneous reduction of soot and NOx emissions in diesel engines. Measuring extremely low levels of soot emissions achievable with LTC modes using a filter smoke meter requires large sample volumes and repeated measurements to achieve the desired data precision and accuracy. Even taking such measures, doubt exists as to whether filter smoke number (FSN) accurately represents the actual smoke emissions emitted from such low soot conditions. The use of alternative fuels such as biodiesel also compounds efforts to accurately report soot emissions since the reflectivity of high levels of organic matter found on the particulate matter collected may result in erroneous readings from the optical detector. Using FSN, it is desired to report mass emissions of soot using empirical correlations derived for use with petroleum diesel fuels and conventional modes of combustion. The work presented in this paper compares the experimental results of well known formulas for calculating the mass of soot using FSN and the elemental carbon mass using thermal optical analysis (TOA) over a range of operating conditions and fuels from a four-cylinder direct-injection passenger car diesel engine. The data show that the mass of soot emitted by the engine can be accurately predicted with the smoke meter method utilizing a 3000 ml sample volume over a range of FSN from 0.02 to 1.5. Soot mass exhaust concentration calculated from FSN using the best of the literature expressions and that from TOA taken over all conditions correlated linearly with a slope of 0.99 and R2 value of 0.94. A primary implication of the work is that the level of confidence in reporting the soot mass based on FSN for low soot formation regimes such as LTC is improved for both petroleum diesel and biodiesel fuels.

UHC and CO Emissions Sources From a Light-Duty Diesel Engine Undergoing Late-Injection Low-Temperature Combustion

2009 ◽  
Author(s):  
Isaac W. Ekoto ◽  
William F. Colban ◽  
Paul C. Miles ◽  
Ulf Aronsson ◽  
O¨ivind Andersson ◽  
...  
Keyword(s):  
High Temperature ◽  
Diesel Engine ◽  
Low Temperature ◽  
Injection Timing ◽  
Spatial Distributions ◽  
Low Temperature Combustion ◽  
Light Duty ◽  
Temperature Heat ◽  
Temperature Combustion ◽  
Homogeneous Reactor

Low load carbon monoxide (CO) and unburned hydrocarbon (UHC) emissions sources are examined in an optically accessible, light-duty diesel engine employing a late-injection, low-temperature combustion strategy. The study focus is to identify the cause of the rapid degradation in emissions and efficiency as injection timing is retarded. The in-cylinder progression of mixing and combustion processes is examined through ultraviolet planar laser-induced fluorescence (UV PLIF) imaging of hydrocarbon spatial distributions. Spectrally-resolved, deep-UV LIF measurements are also used to construct late-cycle spatial distributions of CO, C2, and polycyclic aromatic hydrocarbons within the clearance volume. Engine-out emissions measurements and numerical results from both detailed chemistry homogeneous reactor and multidimensional simulations complement the measurements. The measured spatial distributions show that while most fuel accumulates on the bowl-pip during high-temperature heat-release, much of it is transported into the squish-volume by the reverse squish flow. Homogeneous reactor simulations further show that expansion cooling quenches reactions, preventing the transition to high-temperature heat-release for mixtures with an equivalence ratio below 0.6. Lean squish-volume mixtures, coupled with wall heat losses, severely inhibit squish volume fuel oxidation. Further retarding injection timing exacerbates quenching, resulting in a two-fold increase in UHC emissions and a 33% increase in CO, primarily from the squish-volume.

Fuel Effects on Low Temperature Combustion in a Light-Duty Diesel Engine

2010 ◽  
Author(s):  
Alok Warey ◽  
Jean-Paul Hardy ◽  
Manuela Hennequin ◽  
Marek Tatur ◽  
Dean Tomazic ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Low Temperature ◽  
Low Temperature Combustion ◽  
Light Duty ◽  
Temperature Combustion ◽  
Fuel Effects
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