An Experimental Investigation on the Effect of Post-Injection Strategies on Combustion and Emissions in the Low-Temperature Diesel Combustion Regime

2005 ◽  
Vol 129 (1) ◽  
pp. 279-286 ◽  
Author(s):  
Hanho Yun ◽  
Rolf D. Reitz
Keyword(s):  
Low Temperature ◽  
Soot Formation ◽  
Combustion Regime ◽  
Nox Emissions ◽  
Diesel Combustion ◽  
Low Temperature Combustion ◽  
Post Injection ◽  
Temperature Combustion ◽  
Soot Emissions ◽  
Injection Strategies

In order to meet future emissions regulations, new combustion concepts are being developed. Among them, the development of low-temperature diesel combustion systems has received considerable attention. Low NOx emissions are achieved through minimization of peak temperatures during the combustion process. Concurrently, soot formation is inhibited due to a combination of low combustion temperatures and extensive fuel-air premixing. In this study, the effect of late-cycle mixing enhancement by post-injection strategies on combustion and engine-out emissions in the low-temperature (low soot and NOx emissions) combustion regime was experimentally investigated. The baseline operating condition considered for low-temperature combustion was 1500rpm, 3bar IMEP with 50% EGR rate, and extension to high loads was considered by means of post injection. Post-injection strategies gave very favorable emission results in the low-temperature combustion regime at all loads tested in this study. Since post injection leads to late-cycle mixing improvement, further reductions in soot emissions were achieved without deteriorating the NOx emissions. With smaller fuel injected amounts for the second pulse, better soot emissions were found. However, the determination of the dwell between the injections was found to be very important for the emissions.

An Experimental and Numerical Investigation on the Effect of Post Injection Strategies on Combustion and Emissions in the Low-Temperature Diesel Combustion Regime

2005 ◽  
Author(s):  
Hanho Yun ◽  
Yong Sun ◽  
Rolf D. Reitz
Keyword(s):  
Low Temperature ◽  
Soot Formation ◽  
Combustion Regime ◽  
Nox Emissions ◽  
Diesel Combustion ◽  
Low Temperature Combustion ◽  
Post Injection ◽  
Temperature Combustion ◽  
Soot Emissions ◽  
Injection Strategies

In order to meet future emissions regulations, new combustion concepts are being developed. Among them, the development of low-temperature diesel combustion systems has received considerable attention. Low NOx emissions are achieved through minimization of peak temperatures occurring during the combustion process. Concurrently, soot formation is inhibited due to a combination of low combustion temperatures and extensive fuel-air pre-mixing. In this study, the effect of late-cycle mixing enhancement by post injection strategies on combustion and engine-out emissions in the low-temperature combustion regime was investigated experimentally and numerically. The baseline operating condition considered for low-temperature combustion was 1500 rev/min, 3bar IMEP with 50% EGR rate, and extension to high loads was considered by means of post injection. Post injection strategies gave very favorable emission results in the low temperature combustion regime at all loads. With small second fuel injected amounts, better soot emissions were found. However, the determination of the dwell between the injections was found to be very important for the emissions. Since post injection leads to late-cycle mixing improvement, further reductions in soot emissions were achieved without deteriorating the NOx emissions. To explain these results, numerical analysis was also done using the KIVA-CHEMKIN code. The simulations show that optimal combustion requires that the post injection fuel avoid fuel rich regions formed from the main injection.

Soot Emissions of Various Oxygenated Biofuels in Conventional Diesel Combustion and Low-Temperature Combustion Conditions

2012 ◽  
Vol 26 (3) ◽  
pp. 1900-1911 ◽  
Author(s):  
Haifeng Liu ◽  
Xiaojie Bi ◽  
Ming Huo ◽  
Chia-fon F. Lee ◽  
Mingfa Yao
Keyword(s):  
Low Temperature ◽  
Diesel Combustion ◽  
Low Temperature Combustion ◽  
Temperature Combustion ◽  
Soot Emissions

Multiple injection strategies for reducing HC and CO emissions in diesel-methane dual-fuel low temperature combustion

Fuel ◽  
2021 ◽  
Vol 305 ◽  
pp. 121372
Author(s):  
Deivanayagam Hariharan ◽  
Sundar Rajan Krishnan ◽  
Kalyan Kumar Srinivasan ◽  
Aamir Sohail
Keyword(s):  
Low Temperature ◽  
Dual Fuel ◽  
Low Temperature Combustion ◽  
Multiple Injection ◽  
Temperature Combustion ◽  
Injection Strategies

The effect of advanced ignition system on gasoline low temperature combustion

2019 ◽  
pp. 146808741986754
Author(s):  
Hanho Yun ◽  
Cherian Idicheria ◽  
Paul Najt
Keyword(s):  
Low Temperature ◽  
Nox Emissions ◽  
Low Temperature Combustion ◽  
Efficiency Gain ◽  
Ignition System ◽  
Stable Combustion ◽  
Indicated Mean Effective Pressure ◽  
Spark Plug ◽  
Temperature Combustion ◽  
Valve Overlap

Engines operating in low temperature combustion during positive valve overlap operation offer significant benefits of high fuel economy over the low temperature combustion during negative valve overlap operation. Significant efficiency improvement was achieved by the increased gamma and lower pumping loss. However, NOx emissions were increased due to reliance on the flame-induced combustion. In this study, the corona ignition system was evaluated to reduce NOx emissions during positive valve overlap operation while maintaining the benefit of efficiency gain. The tests were performed in a 2.2-L multi-cylinder engine. The results show that the ignition delay is always shorter with the corona ignition system than with the spark plug. The corona ignition system is able to support stable combustion (coefficient of variation of indicated mean effective pressure <3%) in a lower load during positive valve overlap operation than the spark plug, which gives us additional efficiency benefit. Since the corona ignition system promotes simultaneous ignition of the mixture at multiple locations in the combustion chamber as opposed to ignition being limited to the spark gap channel, the dependence of the flame burn for stable combustion during positive valve overlap operation minimizes, which leads to lower NOx emissions over the spark plug.

Modeling Soot Formation Using Reduced PAH Chemistry in n-Heptane Lifted Flames With Application to Low Temperature Combustion

2008 ◽  
Author(s):  
Gokul Vishwanathan ◽  
Rolf D. Reitz
Keyword(s):  
Low Temperature ◽  
Soot Formation ◽  
Numerical Study ◽  
Low Temperature Combustion ◽  
Constant Volume Chamber ◽  
Soot Mass ◽  
Temperature Combustion ◽  
Lifted Flames ◽  
Polycyclic Aromatic ◽  
Species Comparisons

A numerical study of in-cylinder soot formation and oxidation processes in n-heptane lifted flames using various soot inception species has been conducted. In a recent study by the authors, it was found that the soot formation and growth regions in lifted flames were not adequately represented by using acetylene alone as the soot inception species. Comparisons with a conceptual model and available experimental data suggested that the location of soot formation regions could be better represented if polycyclic aromatic hydrocarbon (PAH) species were considered as alternatives to acetylene for soot formation processes. Since the local temperatures are much lower under low temperature combustion (LTC) conditions, it is believed that significant soot mass contribution can be attributed to PAH rather than to acetylene. To quantify and validate the above observations, a reduced n-heptane chemistry mechanism has been extended to include PAH species up to four fused aromatic rings (pyrene). The resulting chemistry mechanism was integrated into the multidimensional CFD code KIVA-CHEMKIN for modeling soot formation in lifted flames in a constant volume chamber. The investigation revealed that a simpler model that only considers up to phenanthrene (three fused rings) as the soot inception species has good possibilities for better soot location predictions. The present work highlights and illustrates the various research challenges toward accurate qualitative and quantitative predictions of soot for new low emission combustion strategies for I.C. engines.

Cost Effective BS-VI Solution - A Combined Low Temperature Combustion and Conventional Diesel Combustion Concepts

2019 ◽  
Author(s):  
Simhachalam Juttu ◽  
Sanjeev Gothekar ◽  
Neelkanth V Marathe ◽  
Nagesh Harishchandra Walke ◽  
Subhanker Dev
Keyword(s):  
Low Temperature ◽  
Cost Effective ◽  
Diesel Combustion ◽  
Low Temperature Combustion ◽  
Temperature Combustion

The role of the diffusion-limited injection in direct dual fuel stratification

2016 ◽  
Vol 18 (4) ◽  
pp. 351-365 ◽  
Author(s):  
Martin Wissink ◽  
Rolf Reitz
Keyword(s):  
Low Temperature ◽  
Heat Release ◽  
Thermal Efficiency ◽  
Soot Formation ◽  
Combustion Stability ◽  
Dual Fuel ◽  
Low Temperature Combustion ◽  
Fuel Stratification ◽  
Diffusion Limited ◽  
Temperature Combustion

Low-temperature combustion offers an attractive combination of high thermal efficiency and low NO x and soot formation at moderate engine load. However, the kinetically-controlled nature of low-temperature combustion yields little authority over the rate of heat release, resulting in a tradeoff between load, noise, and thermal efficiency. While several single-fuel strategies have achieved full-load operation through the use of equivalence ratio stratification, they uniformly require retarded combustion phasing to maintain reasonable noise levels, which comes at the expense of thermal efficiency and combustion stability. Previous work has shown that control over heat release can be greatly improved by combining reactivity stratification in the premixed charge with a diffusion-limited injection that occurs after low-temperature heat release, in a strategy called direct dual fuel stratification. While the previous work has shown how the heat release control offered by direct dual fuel stratification differs from other strategies and how it is enabled by the reactivity stratification created by using two fuels, this paper investigates the effects of the diffusion-limited injection. In particular, the influence of fuel selection and the pressure, timing, and duration of the diffusion-limited injection are examined. Diffusion-limited injection fuel type had a large impact on soot formation, but no appreciable effect on performance or other emissions. Increasing injection pressure was observed to decrease filter smoke number exponentially while improving combustion efficiency. The timing and duration of the diffusion-limited injection offered precise control over the heat release event, but the operating space was limited by a tradeoff between NO x and soot.

Low Temperature Combustion Using Nitrogen Enrichment to Mitigate NOx From Large Bore Gas-Fueled Engines

2008 ◽  
Author(s):  
Munidhar S. Biruduganti ◽  
Sreenath B. Gupta ◽  
Raj Sekar
Keyword(s):  
Low Temperature ◽  
Power Density ◽  
Nox Reduction ◽  
Engine Performance ◽  
Air Separation ◽  
Nitrogen Enrichment ◽  
Nox Emissions ◽  
Low Temperature Combustion ◽  
Lean Burn ◽  
Temperature Combustion

Low Temperature Combustion (LTC) is identified as one of the pathways to meet the mandatory ultra low NOx emissions levels set by regulatory agencies. This phenomenon can be realized by utilizing various advanced combustion control strategies. The present work discusses nitrogen enrichment using an Air Separation Membrane (ASM) as a better alternative to the mature Exhaust Gas Re-circulation (EGR) technique currently in use. A 70% NOx reduction was realized with a moderate 2% nitrogen enrichment while maintaining power density and simultaneously improving Fuel Conversion Efficiency (FCE). The maximum acceptable Nitrogen Enriched Air (NEA) in a single cylinder spark ignited natural gas engine was investigated in this paper. Any enrichment beyond this level degraded engine performance both in terms of power density and FCE, and unburned hydrocarbon (UHC) emissions. The effect of ignition timing was also studied with and without N2 enrichment. Finally, lean burn versus stoichiometric operation utilizing NEA was compared. Analysis showed that lean burn operation along with NEA is one of the effective pathways for realizing better FCE and lower NOx emissions.

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