Since global warming issue has become an issue of great concern, many major automobile manufacturers have popularized highly efficient and ecofriendly technologies including common rail direct injection (CRDI) diesel and gasoline direct injection (GDI) engines. Recently, especially for diesel engine...
Since global warming issue has become an issue of great concern, many major automobile manufacturers have popularized highly efficient and ecofriendly technologies including common rail direct injection (CRDI) diesel and gasoline direct injection (GDI) engines. Recently, especially for diesel engines, exhaust emission regulations have become stricter than ever due to the introduction of real-driving emission (RDE) and upcoming stringent standards. Those strict regulations have forced automotive engineers to seek other options such as electric vehicles including hybrid electric vehicles and fuel cell electric vehicles. However, because of their potential and demand, internal combustion engine (ICE) technologies should be improved further. As a powerful alternative, the turbocharged LPG direct injection (T-LPDI) engine can lower gaseous and particle emissions simultaneously via the fuel's superior evaporation and clean combustion characteristics. The advanced T-LPDI system was first introduced for passenger vehicles, which could effectively reduce greenhouse gas (GHG) and nanoparticle emissions to a greater extent than the modern GDI system. Many studies have also been undertaken on LPG-fueled engines and vehicles to deal with the environmental issues, and the advantages and disadvantages have been discussed and compared to those of gasoline- and diesel-fueled systems.
In this study, the T-LPDI system was adopted in a light-duty truck (LDT) application with relatively severe driving characteristics because of commercial use. The LDTs require higher engine torque performance to ship heavy freight, and their trip distance and duration are much longer than passenger vehicles. Therefore, engines for LDTs should be developed to satisfy engine performance and exhaust emission performance simultaneously. A T-LPDI engine and vehicle were newly developed using the Atkinson cycle, dedicated fuel supply and control system, and evaluated for LDT application compared to base engines and vehicles. The T-LPDI system used a dedicated fuel supply and control system including a high-pressure pump and an injector, which were developed for the LPG fuel system. Through engine tests, the T-LPDI engine performance was developed to produce a higher torque and power than those of base vehicles. Then, engine parameters, such as the lambda, spark ignition timing, fuel injection timing, fuel injection pressure, and variable charge motion (VCM) control strategy, were studied for the dedicated T-LPDI engine system. These engine parameters could affect engine combustion and exhaust emissions, and thus the parameters were calibrated through a parametric study. The T-LPDI engine was installed to the LDT, and the exhaust emission characteristics were investigated under chassis and RDE test results compared to those obtained for base vehicles. The environmental effectiveness of the T-LPDI vehicle was mainly evaluated in terms of GHG (CO2, CH4, and N2O) and nanoparticle (particle mass and number) emissions, and gaseous emissions (HC, CO, and NOx) emissions were also discussed under chassis and RDE tests.
Throughout this study, the T-LPDI system showed powerful performance in terms of GHG and nanoparticle emissions compared to base vehicles. The chassis CO2 emissions improved 10.0% and 10.7% on average compared to those of base diesel and LPG vehicles respectively. Under RDE tests, CO2 emissions from the T-LPDI vehicle reduced by 12.7% than those of base diesel vehicle and 13.4% than those of base LPG vehicle. The nanoparticle emissions from the T-LPDI vehicle were also lower than those of base diesel and LPG vehicles by 10.0% and 83.6% in terms of particle mass (PM) emissions, and 73.4% and 99.2% in terms of particle number (PN) emissions, respectively. The combined effect of the stoichiometric operation, three-way catalyst (TWC), gaseous fuel, Atkinson cycle, and turbocharged direct injection scheme were strongly effective in improving the engine performance and exhaust emission characteristics for LDT applications.
Since global warming issue has become an issue of great concern, many major automobile manufacturers have popularized highly efficient and ecofriendly technologies including common rail direct injection (CRDI) diesel and gasoline direct injection (GDI) engines. Recently, especially for diesel engines, exhaust emission regulations have become stricter than ever due to the introduction of real-driving emission (RDE) and upcoming stringent standards. Those strict regulations have forced automotive engineers to seek other options such as electric vehicles including hybrid electric vehicles and fuel cell electric vehicles. However, because of their potential and demand, internal combustion engine (ICE) technologies should be improved further. As a powerful alternative, the turbocharged LPG direct injection (T-LPDI) engine can lower gaseous and particle emissions simultaneously via the fuel's superior evaporation and clean combustion characteristics. The advanced T-LPDI system was first introduced for passenger vehicles, which could effectively reduce greenhouse gas (GHG) and nanoparticle emissions to a greater extent than the modern GDI system. Many studies have also been undertaken on LPG-fueled engines and vehicles to deal with the environmental issues, and the advantages and disadvantages have been discussed and compared to those of gasoline- and diesel-fueled systems.
In this study, the T-LPDI system was adopted in a light-duty truck (LDT) application with relatively severe driving characteristics because of commercial use. The LDTs require higher engine torque performance to ship heavy freight, and their trip distance and duration are much longer than passenger vehicles. Therefore, engines for LDTs should be developed to satisfy engine performance and exhaust emission performance simultaneously. A T-LPDI engine and vehicle were newly developed using the Atkinson cycle, dedicated fuel supply and control system, and evaluated for LDT application compared to base engines and vehicles. The T-LPDI system used a dedicated fuel supply and control system including a high-pressure pump and an injector, which were developed for the LPG fuel system. Through engine tests, the T-LPDI engine performance was developed to produce a higher torque and power than those of base vehicles. Then, engine parameters, such as the lambda, spark ignition timing, fuel injection timing, fuel injection pressure, and variable charge motion (VCM) control strategy, were studied for the dedicated T-LPDI engine system. These engine parameters could affect engine combustion and exhaust emissions, and thus the parameters were calibrated through a parametric study. The T-LPDI engine was installed to the LDT, and the exhaust emission characteristics were investigated under chassis and RDE test results compared to those obtained for base vehicles. The environmental effectiveness of the T-LPDI vehicle was mainly evaluated in terms of GHG (CO2, CH4, and N2O) and nanoparticle (particle mass and number) emissions, and gaseous emissions (HC, CO, and NOx) emissions were also discussed under chassis and RDE tests.
Throughout this study, the T-LPDI system showed powerful performance in terms of GHG and nanoparticle emissions compared to base vehicles. The chassis CO2 emissions improved 10.0% and 10.7% on average compared to those of base diesel and LPG vehicles respectively. Under RDE tests, CO2 emissions from the T-LPDI vehicle reduced by 12.7% than those of base diesel vehicle and 13.4% than those of base LPG vehicle. The nanoparticle emissions from the T-LPDI vehicle were also lower than those of base diesel and LPG vehicles by 10.0% and 83.6% in terms of particle mass (PM) emissions, and 73.4% and 99.2% in terms of particle number (PN) emissions, respectively. The combined effect of the stoichiometric operation, three-way catalyst (TWC), gaseous fuel, Atkinson cycle, and turbocharged direct injection scheme were strongly effective in improving the engine performance and exhaust emission characteristics for LDT applications.
주제어
#Greenhouse gas (GHG) Nanoparticle emission Unregulated emission Atkinson cycle Light-duty truck Real-driving emission (RDE) LPG direct injection (LPDI)
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