Improving the Efficiency of Low Temperature Combustion Engines Using a Chamfered Ring-Land

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Jae Hyung Lim ◽  
Rolf D. Reitz
Keyword(s):  
Combustion Efficiency ◽  
Low Temperature Combustion ◽  
Combustion Engines ◽  
Compression Ignition ◽  
Reactivity Controlled Compression Ignition ◽  
Indicated Mean Effective Pressure ◽  
Hcci Combustion ◽  
Unburned Hydrocarbon ◽  
Piston Crown ◽  
Temperature Combustion

In the present study, a chamfered piston crown design was used in order to reduce unburned hydrocarbon (UHC) emissions from the ring-pack crevice. Compared to the conventional piston design, the chamfered piston showed 17–41% reduction in the crevice-borne UHC emissions in homogeneous charge compression ignition (HCCI) combustion. Through parametric sweeps 6 mm was identified to be a suitable chamfer size and the mechanism of the UHC reduction was revealed. Based on the findings in this study, the chamfered piston design was also tested in dual-fuel reactivity controlled compression ignition (RCCI) combustion. In the tested RCCI case using the chamfered piston the UHC and CO emissions were reduced by 79% and 36%, respectively, achieving 99.5% combustion efficiency. This also improved gross indicated thermal efficiency (gITE) from 51.1% to 51.8% in a 9 bar indicated mean effective pressure (IMEP) RCCI combustion case.

Improving the Efficiency of Low Temperature Combustion Engines Using a Chamfered Ring-Land

2014 ◽  
Author(s):  
Jae Hyung Lim ◽  
Rolf D. Reitz
Keyword(s):  
Combustion Efficiency ◽  
Dual Fuel ◽  
Low Temperature Combustion ◽  
Combustion Engines ◽  
Compression Ignition ◽  
Reactivity Controlled Compression Ignition ◽  
Hcci Combustion ◽  
Unburned Hydrocarbon ◽  
Piston Crown ◽  
Temperature Combustion

In the present study a chamfered piston crown design was used in order to reduce unburned hydrocarbon (UHC) emissions from the ring-pack crevice. Compared to the conventional piston design, the chamfered piston showed 17%∼41% reduction in the crevice-borne UHC emissions in homogeneous charge compression ignition (HCCI) combustion. Through parametric sweeps 6 mm was identified to be a suitable chamfer size and the mechanism of the UHC reduction was revealed. Based on the findings in this study, the chamfered piston design was also tested in dual-fuel reactivity controlled compression ignition (RCCI) combustion. In the tested RCCI case using the chamfered piston the UHC and CO emissions were reduced by 79% and 36%, respectively, achieving 99.5% combustion efficiency. This also improved gross indicated thermal efficiency from 51.1% to 51.8% in a 9 bar IMEP RCCI combustion case.

A Study of Combustion Inefficiency in Diesel Low Temperature Combustion and Gasoline–Diesel RCCI Via Detailed Emission Measurement

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Shouvik Dev ◽  
Prasad Divekar ◽  
Kelvin Xie ◽  
Xiaoye Han ◽  
Xiang Chen ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Low Temperature ◽  
Combustion Products ◽  
Combustion Efficiency ◽  
Emission Measurement ◽  
Low Temperature Combustion ◽  
Compression Ignition ◽  
Incomplete Combustion ◽  
Temperature Combustion ◽  
Energy Penalty

Reduction of engine-out NOx emissions to ultra-low levels is facilitated by enabling low temperature combustion (LTC) strategies. However, there is a significant energy penalty in terms of combustion efficiency as evidenced by the high levels of hydrocarbon (HC), carbon monoxide (CO), and hydrogen emissions. In this work, the net fuel energy lost as a result of incomplete combustion in two different LTC regimes is studied—partially premixed compression ignition (PPCI) using in-cylinder injection of diesel fuel and reactivity controlled compression ignition (RCCI) of port injected gasoline and direct injected diesel. A detailed analysis of the incomplete combustion products was conducted. Test results indicated that carbon monoxide (CO), hydrogen, and light hydrocarbon (HC) made up for most of the combustion in-efficiency in the PPCI mode, while heavier HC and aromatics were significantly higher in the RCCI mode.

scholarly journals An Experimental Investigation on the Influence of Port Injection at Valve on Combustion and Emission Characteristics of B5/Biogas RCCI Engine

2020 ◽  
Vol 10 (2) ◽  
pp. 452
Author(s):  
Ibrahim B. Dalha ◽  
Mior A. Said ◽  
Zainal A. Abdul Karim ◽  
Salah E. Mohammed
Keyword(s):  
Fuel Mixture ◽  
Injection Timing ◽  
Compression Ignition ◽  
Reactivity Controlled Compression Ignition ◽  
Indicated Mean Effective Pressure ◽  
Unburned Hydrocarbon ◽  
Crank Angle ◽  
Slow Combustion ◽  
Low Load ◽  
Co Emission

High unburned hydrocarbon (UHC) and carbon monoxide (CO) emissions, on account of the premixed air-fuel mixture entering the crevices and pre-mature combustion, are setbacks to reactivity-controlled compression ignition (RCCI) combustion at a low load. The influence of direct-injected B5 and port injection of biogas at the intake valve was, experimentally, examined in the RCCI mode. The port injection at the valve was to elevate the temperature at low load and eliminate premixing for reduced pre-mature combustion and fuel entering the crevices. An advanced injection timing of 21° crank angle before top dead centre and fraction of 50% each of the fuels, were maintained at speeds of 1600, 1800 and 2000 rpm and varied the load from 4.5 to 6.5 bar indicated mean effective pressure (IMEP). The result shows slow combustion as the load increases with the highest indicated thermal efficiency of 36.33% at 5.5 bar IMEP. The carbon dioxide and nitrogen oxides emissions increased, but UHC emission decreased, significantly, as the load increases. However, CO emission rose from 4.5 to 5.5 bar IMEP, then reduced as the load increases. The use of these fuels and biogas injection at the valve were capable of averagely reducing the persistent challenge of the CO and UHC emissions, by 20.33% and 10% respectively, compared to the conventional premixed mode.

scholarly journals Multipulse Ballistic Injection: A Novel Method for Improving Low Temperature Combustion with Early Injection Timings

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3727
Author(s):  
Márton Virt ◽  
Gergely Granovitter ◽  
Máté Zöldy ◽  
Ádám Bárdos ◽  
Ádám Nyerges
Keyword(s):  
Low Temperature ◽  
Combustion Efficiency ◽  
Low Temperature Combustion ◽  
Indicated Mean Effective Pressure ◽  
Temperature Combustion ◽  
Combustion Technology ◽  
Novel Method ◽  
Wall Wetting ◽  
Gas Recirculation ◽  
Early Injection

Nowadays, increasingly stricter regulations on emission reduction are inducing rapid developments in combustion science. Low-temperature combustion (LTC) is an advanced combustion technology that increases an engine’s thermal efficiency and even provides low emissions of nitrogen oxides (NOx) and particulate matter (PM). The technology often uses early direct injections to achieve sufficient mixture homogeneity. This leads to increasing wall wetting and lower combustion efficiency. This paper introduces the Multipulse ballistic injection (MBI) method to improve combustion with early injection timings. The research was carried out in a four-cylinder medium-duty diesel engine with high-pressure exhaust gas recirculation (HP-EGR). The investigation was divided into two experiments. In the first experiment, MBI was examined without EGR, and in the second, EGR was applied to study its effects. It was found that the MBI strategy decreased wall wetting and increased homogeneity and the indicated mean effective pressure (IMEP) at early injection angles.

scholarly journals Impact of injection strategies on combustion characteristics, efficiency and emissions of gasoline compression ignition operation in a heavy-duty multi-cylinder engine

2018 ◽  
Vol 21 (8) ◽  
pp. 1426-1440 ◽  
Author(s):  
Buyu Wang ◽  
Michael Pamminger ◽  
Ryan Vojtech ◽  
Thomas Wallner
Keyword(s):  
High Temperature ◽  
Thermal Efficiency ◽  
Fuel Injection ◽  
Pressure Rise ◽  
Pilot Injection ◽  
Low Temperature Combustion ◽  
Compression Ignition ◽  
Temperature Combustion ◽  
Gas Recirculation ◽  
Direct Fuel Injection

Gasoline compression ignition using a single gasoline-type fuel for direct/port injection has been shown as a method to achieve low-temperature combustion with low engine-out NOx and soot emissions and high indicated thermal efficiency. However, key technical barriers to achieving low-temperature combustion on multi-cylinder engines include the air handling system (limited amount of exhaust gas recirculation) as well as mechanical engine limitations (e.g. peak pressure rise rate). In light of these limitations, high-temperature combustion with reduced amounts of exhaust gas recirculation appears more practical. Furthermore, for high-temperature gasoline compression ignition, an effective aftertreatment system allows high thermal efficiency with low tailpipe-out emissions. In this work, experimental testing was conducted on a 12.4 L multi-cylinder heavy-duty diesel engine operating with high-temperature gasoline compression ignition combustion with port and direct injection. Engine testing was conducted at an engine speed of 1038 r/min and brake mean effective pressure of 1.4 MPa for three injection strategies, late pilot injection, early pilot injection, and port/direct fuel injection. The impact on engine performance and emissions with respect to varying the combustion phasing were quantified within this study. At the same combustion phasing, early pilot injection and port/direct fuel injection had an earlier start of combustion and higher maximum pressure rise rates than late pilot injection attributable to more premixed fuel from pilot or port injection; however, brake thermal efficiencies were higher with late pilot injection due to reduced heat transfer. Early pilot injection also exhibited the highest cylinder-to-cylinder variations due to differences in injector behavior as well as the spray/wall interactions affecting mixing and evaporation process. Overall, peak brake thermal efficiency of 46.1% and 46% for late pilot injection and port/direct fuel injection was achieved comparable to diesel baseline (45.9%), while early pilot injection showed the lowest brake thermal efficiency (45.3%).

Performance of multi-dimensional models for simulating diesel premixed charge compression ignition engine combustion using low- and high-pressure injectors

2005 ◽  
Vol 6 (5) ◽  
pp. 475-486 ◽  
Author(s):  
S-C Kong ◽  
Y Ra ◽  
R D Reitz
Keyword(s):  
High Pressure ◽  
Low Temperature ◽  
Spray Angle ◽  
Low Temperature Combustion ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Detailed Chemistry ◽  
Engine Combustion ◽  
Temperature Combustion ◽  
Hsdi Diesel Engine

An engine CFD model has been developed to simulate premixed charge compression ignition (PCCI) combustion using detailed chemistry. The numerical model is based on the KIVA code that is modified to use CHEMKIN as the chemistry solver. The model was applied to simulate ignition, combustion, and emissions processes in diesel engines operated to achieve PCCI conditions. Diesel PCCI experiments using both low- and high-pressure injectors were simulated. For the low-pressure injector with early injection (close to intake valve closure), the model shows that wall wetting can be minimized by using a pressure-swirl atomizer with a variable spray angle. In the case of using a high-pressure injector, it is found that late injection (SOI = 5 ° ATDC) benefits soot emissions as a result of low-temperature combustion at highly premixed conditions. The model was also used to validate the emission reduction potential of an HSDI diesel engine using a double injection strategy that favours PCCI conditions. It is concluded that the present model is useful to assess future engine combustion concepts, such as PCCI and low-temperature combustion (LTC).

Investigating Fuel Condensation Processes in Low Temperature Combustion Engines

2014 ◽  
Author(s):  
Lu Qiu ◽  
Rolf D. Reitz
Keyword(s):  
Low Temperature ◽  
Combustion Engine ◽  
Phase Region ◽  
Low Temperature Combustion ◽  
Combustion Engines ◽  
Two Phase ◽  
Temperature Combustion ◽  
Real Gas Effects ◽  
Unburned Hydrocarbons ◽  
Late Stages

Condensation of gaseous fuel is investigated in a low temperature combustion engine fueled with double direct-injected diesel and premixed gasoline at two load conditions. Possible condensation is examined by considering real gas effects with the Peng-Robinson equation of state and assuming thermodynamic equilibrium of the two fuels. The simulations show that three representative condensation events are observed. The first two condensations are found in the spray some time after the two direct injections, when the evaporative cooling reduces the local temperature until phase separation occurs. The third condensation event occurs during the late stages of the expansion stroke, during which the continuous expansion sends the local fluid into the two-phase region again. Condensation was not found to greatly affect global parameters, such as the average cylinder pressure and temperature mainly because, before the main combustion event, the condensed phase was converted back to the vapor phase due to compression and/or first stage heat release. However, condensed fuel is shown to affect the emission predictions, including engine-out particulate matter and unburned hydrocarbons.

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