Experiments were conducted on a diesel-methanol dual-fuel(DMDF)engine modified by a six-cylinder,turbocharged,inter-cooled diesel engine.According to the number of diesel injection,the experiments are divided to two p...Experiments were conducted on a diesel-methanol dual-fuel(DMDF)engine modified by a six-cylinder,turbocharged,inter-cooled diesel engine.According to the number of diesel injection,the experiments are divided to two parts:the single injectionmode and double injectionmode.The results show that,at the double injectionmode,themaximumof pressure rise rate is small and the engine runs smoothly,however,knock still occurswhen the cocombustion ratio(CCR)is big enough.Under knock status,the power density of the block vibration concentrating at some special frequencies rises dramatically,and the special frequency of single injection mode(about 4.1 kHz)is lower than that of double injection mode(7–9 kHz).The cylinder pressure oscillations of knock status are very different fromthe non-knock status.Under knock status,cylinder pressure oscillations become more concentrated and fiercer at some special frequencies,and the same as the block vibration.The special frequency of single injection mode(3–6 kHz)is lower than that of double injection mode(above 9 kHz).展开更多
This study considers the effect of Eichhornia Crassipes Biodiesel(ECB)blends on the performances,combustion,and emission characteristics of a direct injection compression ignition engine operated in a dual-fuel mode(D...This study considers the effect of Eichhornia Crassipes Biodiesel(ECB)blends on the performances,combustion,and emission characteristics of a direct injection compression ignition engine operated in a dual-fuel mode(DFM)and equipped with an Exhaust gas recirculation technique(EGR).In particular,a single-cylinder,four-stroke,water-cooled diesel engine was utilized and four modes of fuel operation were considered:mode I,the engine operated with an ordinary diesel fuel;mode II,the engine operated with the addition of 2.4 L/min of lique-fied petroleum gas(LPG)and 20%EGR;mode III,20%ECB with 2.4 L/min LPG and 20%EGR;mode IV,40%ECB with 2.4 L/min LPG and 20%EGR.The operation conditions were constant engine speed(1500 rpm),var-iation of load(25%,50%,75%,and 100%),full load,with a compression ratio of 18,and a time injection of 23°BTDC(Before top died center).With regard to engine emissions,carbon dioxide(CO_(2)),carbon monoxide(CO),hydrocarbons(UHC),and nitrogen oxide(NOX)were measured using a gas analyzer.The smoke opacity was measured using an OPABOX smoke meter.By comparing the results related to the different modes with mode I at full load,the BTE(Brake thermal efficiency)increased by 20.17%,11.45%,and 12.66%with modes II,III,and IV,respectively.In comparison to the results for mode II,the BTE decreased due to the combustion of ECB blends by 7.26%and 6.24%for mode III and mode IV,respectively,at full load.In comparison to mode II,the Brake specific energy consumption(BSEC)increased with the ECB substitution.With ECB blends,there is a noticeable decrease in the CO,CO_(2),and UHC emissions at a partial load.Furthermore,the 20%ECB has no effect on CO emissions at full load.For modes II and IV,the CO_(2)increased by 33.33%and 19%,respectively,while the UHC emissions were reduced by 14.49%for mode III and 26.08%for mode IV.The smoke of mode III was lower by 7.21%,but for mode IV,it was higher by 12.37%.In addition,with mode III and mode IV,the NOx emissions increased by 30.50%and 18.80%,respectively.展开更多
As of 2020,shipping companies will have to use low-sulphur fuels to comply with current international regulations set out in Annex VI of the MARPOL Agreement(regulations for the prevention of air pollution from ships)...As of 2020,shipping companies will have to use low-sulphur fuels to comply with current international regulations set out in Annex VI of the MARPOL Agreement(regulations for the prevention of air pollution from ships),which will limit the maximum sulphur content in marine fuels to 0.5%.It is against this backdrop that natural gas(LNG)is being considered as one of the primary alternative fuels to enable compliance with this international regulation.Currently,there are 103 LNG-fuelled vessels in operation around the world and 97 on order.Car and passenger vessels make up the largest segment,accounting for 40 of the 103;none of these,however,is a high-speed(HSC)ropax vessel with capacity for both passengers and trucksi n open seas.HSC vessels are deployed in niche markets requiring high-speed propulsion engines(around 1,000 rpm)that can maintain service speeds.Existing LNG dual-fuel engines cannot be used to retrofit HSC vessels as they have been developed from a range of medium-speed engines(around 500-700 rpm)and they are heavier than those high-speed engines traditionally used by the HSC industry.This paper presents the innovative technology developed for the world’s first adaptation of a high-speed engine to LNG dual-fuel use by the shipping company Fred.Olsen S.A.,within the GAINN4SHIP INNOVATION project.展开更多
Nowadays alternative and innovative energy recovery solutions are adopted on board ships to reduce fuel consumption and harmful emissions.According to this,the present work compares the engine exhaust gas waste heat r...Nowadays alternative and innovative energy recovery solutions are adopted on board ships to reduce fuel consumption and harmful emissions.According to this,the present work compares the engine exhaust gas waste heat recovery and hybrid turbocharger technologies,which are used to improve the efficiency of a dual-fuel four-stroke(DF)marine engine.Both solutions aim to satisfy partly or entirely the ship’s electrical and/or thermal loads.For the engine exhaust gas waste heat recovery,two steam plant schemes are considered:the single steam pressure and the variable layout(single or dual steam pressure plant).In both cases,a heat recovery steam generator is used for the electric power energy generation through a steam turbine.The hybrid turbocharger is used to provide a part of the ship’s electric loads as well.The thermodynamic mathematical models of DF engines,integrated with the energy recovery systems,are developed in a Matlab-Simulink environment,allowing the comparison in terms of performance at different engine loads and fuels,which are Natural Gas(NG)and High Fuel Oil(HFO).The use of NG always involves better efficiency of the system for all the engine working conditions.It results that the highest efficiency value achievable is 56%at 50%maximum continuous rating(MCR)engine load.展开更多
In this study,environmental and economic examinations of Liquefied Natural Gas(LNG)investments are conducted.A year-long noon report data is received from a container ship and LNG conversion is performed.Savings from ...In this study,environmental and economic examinations of Liquefied Natural Gas(LNG)investments are conducted.A year-long noon report data is received from a container ship and LNG conversion is performed.Savings from both the fuel expenses and the amount of the emissions are calculated and presented.To eliminate the fuel consumption uncertainties in future operation periods of the stated ship,different scenarios that simulate various fuel consumption statuses are created and analyzed within the Monte Carlo Simulation method.Lastly,calculations are made with two different time prices,approx.one and half year apart.As a result of the analyses,LNG can provide high environmental benefits since it reduces 99%for SOx,95%for PM10,95%for PM2.5,41%for CO_(2),and 82%for NOx,respectively.It is also determined that LNG investment is highly sensitive to fuel prices.In addition,the LNG usage can be beneficial for maritime companies in terms of marine policies such as paying carbon tax based on the expanding European Union Emission Trade System to maritime business.Still,it needs supportive carbon reduction method to comply with the maritime decarbonization strategy.This study has great importance in that the economic analysis way presented is able to adapt any alternative fuel system conversion for the maritime industry.展开更多
In this experimental work,an optically accessible rapid compression machine is used to study the ignition and combustion process under engine relevant operation conditions for five different air-natural gas equivalenc...In this experimental work,an optically accessible rapid compression machine is used to study the ignition and combustion process under engine relevant operation conditions for five different air-natural gas equivalence ratios(λ)ignited with either 12.2 mg or 6.7 mg of pilot diesel injected at 1,600 bar.Initial temperature of the ambient mixture,walls and injector was 333 K.Additionally,for the short(6.7 mg)diesel injection,the variation in the ID(ignition delay)for two higher ambient temperatures(343 K and 353 K)was measured.Pressure and piston displacement are recorded while two high-speed cameras simultaneously capture signals in the visible range spectrum and at 305 nm wavelength for OH^(*)chemiluminescence respectively.ID is measured both from OH^(*)and pressure rise.From the recorded data,the heat release ratio is estimated and compared with the visual signals.This gives an insight of the temporal and spatial evolution of the flame,as well as a qualitative perception of the transition from spray ignition into a premixed flame in the ambient fuel-air mixture.It was found that increasing the methane concertation delays the ignition,reduces the natural flame luminosity and enhances the OH^(*)chemiluminescence signal.展开更多
基金funded by the Science Research Project of State Grid Shaanxi Electric Power Company(5226 KY22001J)Yulin Science and Technology Planning Project(CXY-2020-024)+1 种基金Natural Science Basic Research Plan of Shaanxi(2018JQ5115,2020JM-243)the Special Fund for Basic Scientific Research of Central Colleges,Chang’an University(2018JQ5115).
文摘Experiments were conducted on a diesel-methanol dual-fuel(DMDF)engine modified by a six-cylinder,turbocharged,inter-cooled diesel engine.According to the number of diesel injection,the experiments are divided to two parts:the single injectionmode and double injectionmode.The results show that,at the double injectionmode,themaximumof pressure rise rate is small and the engine runs smoothly,however,knock still occurswhen the cocombustion ratio(CCR)is big enough.Under knock status,the power density of the block vibration concentrating at some special frequencies rises dramatically,and the special frequency of single injection mode(about 4.1 kHz)is lower than that of double injection mode(7–9 kHz).The cylinder pressure oscillations of knock status are very different fromthe non-knock status.Under knock status,cylinder pressure oscillations become more concentrated and fiercer at some special frequencies,and the same as the block vibration.The special frequency of single injection mode(3–6 kHz)is lower than that of double injection mode(above 9 kHz).
文摘This study considers the effect of Eichhornia Crassipes Biodiesel(ECB)blends on the performances,combustion,and emission characteristics of a direct injection compression ignition engine operated in a dual-fuel mode(DFM)and equipped with an Exhaust gas recirculation technique(EGR).In particular,a single-cylinder,four-stroke,water-cooled diesel engine was utilized and four modes of fuel operation were considered:mode I,the engine operated with an ordinary diesel fuel;mode II,the engine operated with the addition of 2.4 L/min of lique-fied petroleum gas(LPG)and 20%EGR;mode III,20%ECB with 2.4 L/min LPG and 20%EGR;mode IV,40%ECB with 2.4 L/min LPG and 20%EGR.The operation conditions were constant engine speed(1500 rpm),var-iation of load(25%,50%,75%,and 100%),full load,with a compression ratio of 18,and a time injection of 23°BTDC(Before top died center).With regard to engine emissions,carbon dioxide(CO_(2)),carbon monoxide(CO),hydrocarbons(UHC),and nitrogen oxide(NOX)were measured using a gas analyzer.The smoke opacity was measured using an OPABOX smoke meter.By comparing the results related to the different modes with mode I at full load,the BTE(Brake thermal efficiency)increased by 20.17%,11.45%,and 12.66%with modes II,III,and IV,respectively.In comparison to the results for mode II,the BTE decreased due to the combustion of ECB blends by 7.26%and 6.24%for mode III and mode IV,respectively,at full load.In comparison to mode II,the Brake specific energy consumption(BSEC)increased with the ECB substitution.With ECB blends,there is a noticeable decrease in the CO,CO_(2),and UHC emissions at a partial load.Furthermore,the 20%ECB has no effect on CO emissions at full load.For modes II and IV,the CO_(2)increased by 33.33%and 19%,respectively,while the UHC emissions were reduced by 14.49%for mode III and 26.08%for mode IV.The smoke of mode III was lower by 7.21%,but for mode IV,it was higher by 12.37%.In addition,with mode III and mode IV,the NOx emissions increased by 30.50%and 18.80%,respectively.
文摘As of 2020,shipping companies will have to use low-sulphur fuels to comply with current international regulations set out in Annex VI of the MARPOL Agreement(regulations for the prevention of air pollution from ships),which will limit the maximum sulphur content in marine fuels to 0.5%.It is against this backdrop that natural gas(LNG)is being considered as one of the primary alternative fuels to enable compliance with this international regulation.Currently,there are 103 LNG-fuelled vessels in operation around the world and 97 on order.Car and passenger vessels make up the largest segment,accounting for 40 of the 103;none of these,however,is a high-speed(HSC)ropax vessel with capacity for both passengers and trucksi n open seas.HSC vessels are deployed in niche markets requiring high-speed propulsion engines(around 1,000 rpm)that can maintain service speeds.Existing LNG dual-fuel engines cannot be used to retrofit HSC vessels as they have been developed from a range of medium-speed engines(around 500-700 rpm)and they are heavier than those high-speed engines traditionally used by the HSC industry.This paper presents the innovative technology developed for the world’s first adaptation of a high-speed engine to LNG dual-fuel use by the shipping company Fred.Olsen S.A.,within the GAINN4SHIP INNOVATION project.
文摘Nowadays alternative and innovative energy recovery solutions are adopted on board ships to reduce fuel consumption and harmful emissions.According to this,the present work compares the engine exhaust gas waste heat recovery and hybrid turbocharger technologies,which are used to improve the efficiency of a dual-fuel four-stroke(DF)marine engine.Both solutions aim to satisfy partly or entirely the ship’s electrical and/or thermal loads.For the engine exhaust gas waste heat recovery,two steam plant schemes are considered:the single steam pressure and the variable layout(single or dual steam pressure plant).In both cases,a heat recovery steam generator is used for the electric power energy generation through a steam turbine.The hybrid turbocharger is used to provide a part of the ship’s electric loads as well.The thermodynamic mathematical models of DF engines,integrated with the energy recovery systems,are developed in a Matlab-Simulink environment,allowing the comparison in terms of performance at different engine loads and fuels,which are Natural Gas(NG)and High Fuel Oil(HFO).The use of NG always involves better efficiency of the system for all the engine working conditions.It results that the highest efficiency value achievable is 56%at 50%maximum continuous rating(MCR)engine load.
文摘In this study,environmental and economic examinations of Liquefied Natural Gas(LNG)investments are conducted.A year-long noon report data is received from a container ship and LNG conversion is performed.Savings from both the fuel expenses and the amount of the emissions are calculated and presented.To eliminate the fuel consumption uncertainties in future operation periods of the stated ship,different scenarios that simulate various fuel consumption statuses are created and analyzed within the Monte Carlo Simulation method.Lastly,calculations are made with two different time prices,approx.one and half year apart.As a result of the analyses,LNG can provide high environmental benefits since it reduces 99%for SOx,95%for PM10,95%for PM2.5,41%for CO_(2),and 82%for NOx,respectively.It is also determined that LNG investment is highly sensitive to fuel prices.In addition,the LNG usage can be beneficial for maritime companies in terms of marine policies such as paying carbon tax based on the expanding European Union Emission Trade System to maritime business.Still,it needs supportive carbon reduction method to comply with the maritime decarbonization strategy.This study has great importance in that the economic analysis way presented is able to adapt any alternative fuel system conversion for the maritime industry.
基金the European Research Council with a“Horizon Europe:Marie Skłodowska-Curie Actions”grant and it can be disseminated freely.
文摘In this experimental work,an optically accessible rapid compression machine is used to study the ignition and combustion process under engine relevant operation conditions for five different air-natural gas equivalence ratios(λ)ignited with either 12.2 mg or 6.7 mg of pilot diesel injected at 1,600 bar.Initial temperature of the ambient mixture,walls and injector was 333 K.Additionally,for the short(6.7 mg)diesel injection,the variation in the ID(ignition delay)for two higher ambient temperatures(343 K and 353 K)was measured.Pressure and piston displacement are recorded while two high-speed cameras simultaneously capture signals in the visible range spectrum and at 305 nm wavelength for OH^(*)chemiluminescence respectively.ID is measured both from OH^(*)and pressure rise.From the recorded data,the heat release ratio is estimated and compared with the visual signals.This gives an insight of the temporal and spatial evolution of the flame,as well as a qualitative perception of the transition from spray ignition into a premixed flame in the ambient fuel-air mixture.It was found that increasing the methane concertation delays the ignition,reduces the natural flame luminosity and enhances the OH^(*)chemiluminescence signal.
