Lean HCCI/Rich SACI Gasoline Combustion Cycling and Three-Way Catalyst for Fuel Efficiency and NOx Reduction

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Yi Chen ◽  
Vojtěch Šíma ◽  
Weiyang Lin ◽  
Jeff Sterniak ◽  
Stanislav.V Bohac
Keyword(s):  
Fuel Efficiency ◽  
Nox Reduction ◽  
Oxygen Storage Capacity ◽  
Oxygen Depletion ◽  
Oxygen Storage ◽  
Excess Oxygen ◽  
Nox Emissions ◽  
Compression Ignition ◽  
Brake Mean Effective Pressure ◽  
Three Way Catalyst

Multimode combustion (MMC) concepts using homogeneous charge compression ignition (HCCI) gasoline combustion at low loads and spark assisted compression ignition (SACI) gasoline combustion at medium loads have the potential for improved fuel efficiency relative to spark ignition (SI) gasoline combustion. Two MMC concepts are compared in this paper with respect to fuel efficiency and tailpipe NOx emissions. The first concept uses stoichiometric HCCI and SACI to allow standard three-way catalyst (TWC) operation. The second concept also uses HCCI and SACI, but cycles between lean and rich combustion and uses a TWC with increased oxygen storage capacity (OSC) for potentially even greater fuel efficiency improvement. This paper performs a preliminary comparison of the two MMC concepts by analyzing two scenarios: (1) cycling between stoichiometric HCCI at 2 bar BMEP (brake mean effective pressure) and stoichiometric SACI at 3 bar BMEP, and (2) cycling between lean HCCI at 2 bar BMEP and rich SACI at 3 bar BMEP. The effects of excess oxygen ratio during HCCI operation and the frequency of oxygen depletion events on TWC performance and fuel efficiency are investigated. Results show that MMC lean/rich cycling can achieve better fuel efficiency than stoichiometric HCCI/SACI cycling. NOx emissions are moderately higher, but may still be low enough to meet current and future emission regulations.

Lean HCCI/Rich SACI Gasoline Combustion Cycling and Three-Way Catalyst for Fuel Efficiency and NOx Reduction

2014 ◽  
Author(s):  
Yi Chen ◽  
Vojtěch Šíma ◽  
Weiyang Lin ◽  
Jeff Sterniak ◽  
Stanislav V. Bohac
Keyword(s):  
Fuel Efficiency ◽  
Nox Reduction ◽  
Oxygen Storage Capacity ◽  
Oxygen Depletion ◽  
Oxygen Storage ◽  
Excess Oxygen ◽  
Nox Emissions ◽  
Compression Ignition ◽  
Brake Mean Effective Pressure ◽  
Three Way Catalyst

Multi-mode combustion (MMC) concepts using homogeneous charge compression ignition (HCCI) gasoline combustion at low loads and spark assisted compression ignition (SACI) gasoline combustion at medium loads have the potential for improved fuel efficiency relative to spark ignition (SI) gasoline combustion. Two MMC concepts are compared in this paper with respect to fuel efficiency and tailpipe NOx emissions. The first concept uses stoichiometric HCCI and SACI to allow standard three-way catalyst (TWC) operation. The second concept also uses HCCI and SACI, but cycles between lean and rich combustion and uses a TWC with increased oxygen storage capacity (OSC) for potentially even greater fuel efficiency improvement. This paper performs a preliminary comparison of the two MMC concepts by analyzing two scenarios: 1) cycling between stoichiometric HCCI at 2 bar BMEP (brake mean effective pressure) and stoichiometric SACI at 3 bar BMEP, and 2) cycling between lean HCCI at 2 bar BMEP and rich SACI at 3 bar BMEP. The effects of excess oxygen ratio during HCCI operation and the frequency of oxygen depletion events on TWC performance and fuel efficiency are investigated. Results show that MMC lean/rich cycling can achieve better fuel efficiency than stoichiometric HCCI/SACI cycling. NOx emissions are moderately higher, but may still be low enough to meet current and future emission regulations.

Rapidly Pulsed Reductants for Diesel NOx Reduction With Lean NOx Traps: Comparison of Alkanes and Alkenes as the Reducing Agent

2016 ◽  
Author(s):  
Amin Reihani ◽  
Brent Patterson ◽  
John Hoard ◽  
Galen B. Fisher ◽  
Joseph R. Theis ◽  
...  
Keyword(s):  
Catalytic Reduction ◽  
Nox Reduction ◽  
Oxygen Storage Capacity ◽  
Pulse Frequency ◽  
Oxygen Storage ◽  
Passenger Cars ◽  
Catalyst Composition ◽  
Nox Conversion ◽  
Lean Nox ◽  
Lean Nox Traps

Lean NOx Traps (LNTs) are often used to reduce NOx on smaller diesel passenger cars where urea-based Selective Catalytic Reduction (SCR) systems may be difficult to package. However, the performance of LNTs at temperatures above 400°C needs to be improved. The use of Rapidly Pulsed Reductants (RPR) is a process in which hydrocarbons are injected in rapid pulses ahead of the LNT in order to improve its performance at higher temperatures and space velocities. This approach was developed by Toyota and was originally called Di-Air (Diesel NOx aftertreatment by Adsorbed Intermediate Reductants) [1]. There is a vast parameter space that needs to be explored in order to maximize the NOx conversion at high temperatures and flow rates while minimizing the fuel penalty associated with the hydrocarbon injections. Four parameters were identified as important for RPR operation: (1) the flow field and reductant mixing uniformity; (2) the pulsing parameters including the pulse frequency, duty cycle, and rich magnitude; (3) the reductant type; and (4) the catalyst composition, including the type and loading of precious metal, the type and loading of NOx storage material, and the amount of oxygen storage capacity (OSC). In this study, RPR performance was assessed between 150°C and 650°C with several reductants including dodecane, propane, ethylene, propylene, H2, and CO. A novel injection and mixer system was designed that allowed for the investigation of previously unexplored areas of high frequency injections up to f = 100Hz. Under RPR conditions, H2, CO, dodecane, and C2H4 provided approximately 80% NOx conversion at 500°C, but at 600°C the conversions were significantly lower, ranging from 40 to 55%. The NOx conversion with C3H8 was low across the entire temperature range, with a maximum conversion of 25% near 300°C and essentially no conversion at 600°C. In contrast, C3H6 provided greater than 90% NOx conversion over a broad range of temperature between 280°C and 630°C. Among the hydrocarbons, this suggested that the high temperature NOx conversion with RPR improves as the reactivity of the hydrocarbon increases.

Low Cetane Fuels in Compression Ignition Engine to Achieve LTC

2011 ◽  
Author(s):  
Swami Nathan Subramanian ◽  
Stephen Ciatti
Keyword(s):  
Low Temperature ◽  
Internal Combustion Engines ◽  
High Efficiency ◽  
Fuel Efficiency ◽  
Nox Emissions ◽  
Low Temperature Combustion ◽  
Compression Ignition ◽  
Oxides Of Nitrogen ◽  
Compression Ignition Engine ◽  
Conventional Combustion

The conventional combustion processes of Spark Ignition (SI) and Compression Ignition (CI) have their respective merits and demerits. Internal combustion engines use certain fuels to utilize those conventional combustion technologies. High octane fuels are required to operate the engine in SI mode, while high cetane fuels are preferable for CI mode of operation. Those conventional combustion techniques struggle to meet the current emissions norms while retaining high efficiency. In particular, oxides of nitrogen (NOx) and particulate matter (PM) emissions have limited the utilization of diesel fuel in compression ignition engines, and conventional gasoline operated SI engines are not fuel efficient. Advanced combustion concepts have shown the potential to combine fuel efficiency and improved emissions performance. Low Temperature Combustion (LTC) offers reduced NOx and PM emissions with comparable modern diesel engine efficiencies. The ability of premixed, low-temperature compression ignition to deliver low PM and NOx emissions is dependent on achieving optimal combustion phasing. Variations in injection pressures, injection schemes and Exhaust Gas Recirculation (EGR) are studied with low octane gasoline LTC. Reductions in emissions are a function of combustion phasing and local equivalence ratio. Engine speed, load, EGR quantity, compression ratio and fuel octane number are all factors that influence combustion phasing. Low cetane fuels have shown comparable diesel efficiencies with low NOx emissions at reasonably high power densities.

Overview: Modification of Cerium Oxide in Three-Way Catalysts

2014 ◽  
Vol 575 ◽  
pp. 97-102 ◽  
Author(s):  
M. Nazri Abu Shah ◽  
S. Hanim Md Nor ◽  
Kamariah Noor Ismail ◽  
Abdul Hadi
Keyword(s):  
Thermal Stability ◽  
Rare Earth ◽  
Metal Oxides ◽  
Cerium Oxide ◽  
Storage Capacity ◽  
Rare Earth Metals ◽  
Oxygen Storage Capacity ◽  
Oxygen Storage ◽  
Alkaline Metals ◽  
Three Way Catalyst

An overview of modification of cerium oxide, CeO2which is employed in the three-way catalyst (TWCs) is presented in this article. The modifications of cerium oxide, CeO2incorporated with the metal oxides for the improvement of thermal stability, microstructure and oxygen storage capacity (OSC) are discussed. In view of that, the types of metal oxide are grouped into transition metals, rare earth metals, and alkaline metals and the effect of each group into cerium oxide, CeO2are elaborated.

An Experimental Investigation of Low-Octane Gasoline in Diesel Engines

2011 ◽  
Vol 133 (9) ◽  
Author(s):  
Stephen Ciatti ◽  
Swami Nathan Subramanian
Keyword(s):  
Low Temperature ◽  
Fuel Efficiency ◽  
Nox Emissions ◽  
Low Temperature Combustion ◽  
Compression Ignition ◽  
Oxides Of Nitrogen ◽  
Conventional Combustion ◽  
Compression Ignition Engines ◽  
Temperature Combustion ◽  
Power Densities

Conventional combustion techniques struggle to meet the current emissions norms. In particular, oxides of nitrogen (NOx) and particulate matter (PM) emissions have limited the utilization of diesel fuel in compression ignition engines. Advance combustion concepts have proved the potential to combine fuel efficiency and improved emission performance. Low-temperature combustion (LTC) offers reduced NOx and PM emissions with comparable modern diesel engine efficiencies. The ability of premixed, low-temperature compression ignition to deliver low PM and NOx emissions is dependent on achieving optimal combustion phasing. Diesel operated LTC is limited by early knocking combustion, whereas conventional gasoline operated LTC is limited by misfiring. So the concept of using an unconventional fuel with the properties in between those two boundary fuels has been experimented in this paper. Low-octane (84 RON) gasoline has shown comparable diesel efficiencies with the lowest NOx emissions at reasonable high power densities (NOx emission was 1 g/kW h at 12 bar BMEP and 2750 rpm).

An Experimental Investigation of Low Octane Gasoline in Diesel Engines

2010 ◽  
Author(s):  
Stephen Ciatti ◽  
Swami Nathan Subramanian
Keyword(s):  
Low Temperature ◽  
Fuel Efficiency ◽  
Nox Emissions ◽  
Low Temperature Combustion ◽  
Compression Ignition ◽  
Oxides Of Nitrogen ◽  
Conventional Combustion ◽  
Compression Ignition Engines ◽  
Temperature Combustion ◽  
Power Densities

Conventional combustion techniques struggle to meet the current emissions norms. In particular, oxides of nitrogen (NOx) and particulate matter (PM) emissions have limited the utilization of diesel fuel in compression ignition engines. Advance combustion concepts have proved the potential to combine fuel efficiency and improved emissions performance. Low Temperature Combustion (LTC) offers reduced NOx and PM emissions with comparable modern diesel engine efficiencies. The ability of premixed, low-temperature compression ignition to deliver low PM and NOx emissions is dependent on achieving optimal combustion phasing. Diesel operated LTC is limited by early knocking combustion whereas conventional gasoline operated LTC is limited by misfiring. So the concept of using an unconventional fuel with the properties in between those two boundary fuels has been experimented in this paper. Low octane (84 RON) gasoline has shown comparable diesel efficiencies with lowest NOx emissions at reasonable high power densities (NOx emission were 1 g/kW-hr at 12 bar BMEP and 2750 rpm).

Automotive Three-Way Catalyst Diagnostics with Experimental Results

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
Brandon M. Dawson ◽  
Matthew A. Franchek ◽  
Karolos Grigoriadis ◽  
Robert W. McCabe ◽  
Mike Uhrich ◽  
...  
Keyword(s):  
Instrumental Variables ◽  
Storage Capacity ◽  
Test Procedure ◽  
Oxygen Storage Capacity ◽  
Oxygen Storage ◽  
Model Structure ◽  
Information Synthesis ◽  
Catalyst Temperature ◽  
Useful Life ◽  
Three Way Catalyst

Presented is the model based diagnostics of a three-way catalyst (TWC). The proposed TWC model relates measurable engine inputs (engine air mass (AM) and catalyst temperature) to a metric that quantifies TWC oxygen storage capacity. The TWC model structure is based on the dynamics of the TWC and identified using orthogonal least squares (OLS). The model coefficients are estimated using an instrumental variables four step (IV4) approach. TWC diagnostics is realized by means of an information synthesis (IS) technique where changes in the adapted TWC model coefficients are utilized to estimate TWC health. The approach is experimentally validated on a federal test procedure (FTP) drive cycle for healthy (full useful life, FUL) and failed (threshold) TWCs. The results will show that a 100% accurate classification in TWC health estimation (FUL or threshold) is produced for the catalysts tested.

Measurement of Oxygen Storage Capacity of Three-Way Catalyst and Optimization of A/F Perturbation Control to Its Characteristics

2002 ◽  
Author(s):  
Kouji Miyamoto ◽  
Hiroyuki Takebayashi ◽  
Takahisa Ishihara ◽  
Hiroyuki Kido ◽  
Koichi Hatamura
Keyword(s):  
Storage Capacity ◽  
Oxygen Storage Capacity ◽  
Oxygen Storage ◽  
Three Way Catalyst

Influence of doping Mg cation in Fe3O4 lattice on its oxygen storage capacity to use as a catalyst for reducing emissions of a compression ignition engine

Fuel ◽  
2020 ◽  
Vol 272 ◽  
pp. 117728 ◽  
Author(s):  
Nasrin Sabet Sarvestani ◽  
Mohammad Tabasizadeh ◽  
Mohammad Hossein Abbaspour-Fard ◽  
Hamed Nayebzadeh ◽  
Hassan Karimi-Maleh ◽  
...  
Keyword(s):  
Storage Capacity ◽  
Oxygen Storage Capacity ◽  
Oxygen Storage ◽  
Compression Ignition ◽  
Compression Ignition Engine
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