The Efficiency and Emission Characteristics of Dual Fuel Combustion Using Gasoline Direct Injection and Ethanol Port Injection in an SI Engine

2014 ◽  
Author(s):  
Namho Kim ◽  
Seokwon Cho ◽  
Hoimyung Choi ◽  
Han Ho Song ◽  
Kyoungdoug Min
Keyword(s):  
Direct Injection ◽  
Fuel Combustion ◽  
Gasoline Direct Injection ◽  
Dual Fuel ◽  
Emission Characteristics ◽  
Si Engine ◽  
Dual Fuel Combustion

Mapping the combustion modes of a dual-fuel compression ignition engine

2021 ◽  
pp. 146808742110183
Author(s):  
Jonathan Martin ◽  
André Boehman
Keyword(s):  
Direct Injection ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Combustion Modes ◽  
Si Engines ◽  
Dual Fuel Combustion ◽  
Soot Emissions ◽  
Ci Engines

Compression-ignition (CI) engines can produce higher thermal efficiency (TE) and thus lower carbon dioxide (CO2) emissions than spark-ignition (SI) engines. Unfortunately, the overall fuel economy of CI engine vehicles is limited by their emissions of nitrogen oxides (NOx) and soot, which must be mitigated with costly, resource- and energy-intensive aftertreatment. NOx and soot could also be mitigated by adding premixed gasoline to complement the conventional, non-premixed direct injection (DI) of diesel fuel in CI engines. Several such “dual-fuel” combustion modes have been introduced in recent years, but these modes are usually studied individually at discrete conditions. This paper introduces a mapping system for dual-fuel CI modes that links together several previously studied modes across a continuous two-dimensional diagram. This system includes the conventional diesel combustion (CDC) and conventional dual-fuel (CDF) modes; the well-explored advanced combustion modes of HCCI, RCCI, PCCI, and PPCI; and a previously discovered but relatively unexplored combustion mode that is herein titled “Piston-split Dual-Fuel Combustion” or PDFC. Tests show that dual-fuel CI engines can simultaneously increase TE and lower NOx and/or soot emissions at high loads through the use of Partial HCCI (PHCCI). At low loads, PHCCI is not possible, but either PDFC or RCCI can be used to further improve NOx and/or soot emissions, albeit at slightly lower TE. These results lead to a “partial dual-fuel” multi-mode strategy of PHCCI at high loads and CDC at low loads, linked together by PDFC. Drive cycle simulations show that this strategy, when tuned to balance NOx and soot reductions, can reduce engine-out CO2 emissions by about 1% while reducing NOx and soot by about 20% each with respect to CDC. This increases emissions of unburnt hydrocarbons (UHC), still in a treatable range (2.0 g/kWh) but five times as high as CDC, requiring changes in aftertreatment strategy.

Effects of N-Butanol Content on the Dual-Fuel Combustion Mode With CNG at Two Engine Speeds

2018 ◽  
Author(s):  
Xiangyu Meng ◽  
Wuqiang Long ◽  
Yihui Zhou ◽  
Mingshu Bi ◽  
Chia-Fon F. Lee
Keyword(s):  
Thermal Efficiency ◽  
Engine Speed ◽  
Direct Injection ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Combustion Mode ◽  
Start Of Injection ◽  
Wide Range ◽  
Pilot Fuel ◽  
Dual Fuel Combustion

Because of the potential to reduce NOx and PM emissions simultaneously and the utilization of biofuel, diesel/compressed natural gas (CNG) dual-fuel combustion mode with port injection of CNG and direct injection of diesel has been widely studied. While in comparison with conventional diesel combustion mode, the dual-fuel combustion mode generally leads lower thermal efficiency, especially at low and medium load, and higher carbon monoxide (CO) and total hydrocarbons (THC) emissions. In this work, n-butanol was blended with diesel as the pilot fuel to explore the possibility to improve the performance and emissions of dual-fuel combustion mode with CNG. Various pilot fuels of B0 (pure diesel), B10 (90% diesel/10% n-butanol by volume basis), B20 (80% diesel/20% n-butanol) and B30 (70% diesel/30% n-butanol) were compared at the CNG substitution rate of 70% by energy basis under the engine speeds of 1400 and 1800 rpm. The experiments were carried out by sweeping a wide range of pilot fuel start of injection timings based on the same total input energy including pilot fuel and CNG. As n-butanol was added into the pilot fuel, the pilot fuel/CNG/air mixture tends to be more homogeneous. The results showed that for the engine speed of 1400 rpm, pilot fuel with n-butanol addition leads to a slightly lower indicated thermal efficiency (ITE). B30 reveals much lower NOx emission and slightly higher THC emissions. For the engine speed of 1800 rpm, B20 can improve ITE and decrease the NOx and THC emissions simultaneously relative to B0.

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