Title: Effect of Two Stage Turbocharging System and Retarded Intake Valve Closing Timing on Thermal Efficiency and Emissions in a Partially Premixed Combustion Diesel Engine
Abstract:The effects of retarded intake valve closing timing(RIVCT)and two stage turbocharging system matching based on partially premixed combustion strategy were investigated. Tests were performed on a 12,L ...The effects of retarded intake valve closing timing(RIVCT)and two stage turbocharging system matching based on partially premixed combustion strategy were investigated. Tests were performed on a 12,L L6engine at loads up to BMEP of 0.5,MPa. The reasonable control of the intercooler intensity,two-stage compressor operating efficiency and pressure ratio distribution is helpful to improve the engine performance by achieving the minimum driving work,which resulted in the reduced exhaust energy required. RIVCT(where RIVCT is-80°CA ATDC,-65°CA ATDC and-55°CA ATDC at 1,300,r/min,1,600,r/min and 1,900,r/min,respectively)lowers the intake air flow to reduce the back pressure,pumping losses and improve the thermal efficiency. The increase in the proportion of thermal efficiency is different. Thermal efficiency increases by 1%,1.5% and 2%respectively at 1,300,r/min,1,600,r/min and 1,900,r/min. For given injection timing and EGR rate,RIVCT lowers the effective compression ratio and temperature during the compression stroke,resulting in an increased ignition delay as fuel mixes more homogenously with the charge air ahead of combustion. Results show a significant reduction of soot(above 30%). Meanwhile,RIVCT increases the ignition delay to enhance fuel-air mixing,thereby lowering the local flame temperature and resulting in a significant reduction in NOx emissions(above 70%).Read More
Publication Year: 2013
Publication Date: 2013-01-01
Language: en
Type: article
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Cited By Count: 1
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