Effect of natural gas injection timing on combustion performance & methane slip emission of diesel – NG dual fuel engine: An experimental study

2019 ◽  
Author(s):  
Betty Ariani ◽  
I. Made Ariana ◽  
M. Aguk Fathallah
Keyword(s):  
Experimental Study ◽  
Natural Gas ◽  
Gas Injection ◽  
Dual Fuel ◽  
Injection Timing ◽  
Combustion Performance ◽  
Methane Slip

scholarly journals Micro-pilot-induced Ignition Diesel/ Natural Gas Engine Control System Development and Engine Performance /Emission Optimization

2018 ◽  
Author(s):  
G Zhao
Keyword(s):  
Control System ◽  
Natural Gas ◽  
Gas Injection ◽  
Injection Pressure ◽  
Dual Fuel ◽  
Injection Timing ◽  
Gas Engine ◽  
Natural Gas Engine ◽  
Driving Circuit ◽  
Injection Ratio

Diesel/natural gas dual fuel engine is acquiring more and more attention due to its potential to reduce NOX and soot emission simultaneously. Micro-pilot-induced diesel ignition natural gas engine is a popular manner to further improve the emission reduction capability of dual fuel engine. A six cylinder, four stroke, commonrail diesel engine is converted into dual fuel engine. Natural gas is injected into the intake manifold after the throttle. Five gas injection valves are used to control natural gas flow rate. Based to the established fuel supply system, a dual fuel control system is developed by using MS9S12XEP100 MCU. Voltage boosting circuit, fuel injector driving circuit, gas injection valve driving circuit and MeUn driving circuit are integrated on the platform of MCU hardware. Two ECU is connected to each other by CAN bus and several I/O ports to fulfil the fuel injection functional requirement. A software framework involves gas injection timing synchronization, fuel mode managing, multi-time injection. A MAP based fresh air mass flow rate and intake charge efficiency model is integrated in the MCU to calculate the fresh air quality in cylinder. The last part is performance optimization research at low load. Ignition diesel is divided into two stages, and the first injection timing, first injection ratio and injection pressure are used as controllable parameter to reduce NOX and HC emission. Experimental result reveal that by dividing ignition injection into two stage and advancing first injection to 60°CA BTDC CH4 emission can be reduced by 77% while NOX remains unchanged. Increasing the first injection ratio and injection pressure can also reduce THC emission. If injection pressure is higher than 75MPa, the effect of HC reduction effect is not that obvious. Experimental results shows that developed control system can accomplish the functional requirements of dual fuel engine management. Emission test results demonstrate that IMO TierII can be satisfied at diesel mode. DF mode emission performance can meet the requirement of IMO TierIII. Furthermore, as the first domestic product dual fuel dedicated control system, which has passed through the CCS authentication in China, the engine emission level can meet the current and upcoming China’s emission standard on non-road engine on the premise of guaranteeing engine power and economy.

Numerical Investigation of the Performance of a High Pressure Direct Injection (HPDI) Natural Gas Engine

2014 ◽  
Author(s):  
Won Geun Lee ◽  
David Montgomery
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Direct Injection ◽  
Gas Injection ◽  
Load Condition ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Injection Timing ◽  
Pilot Injection ◽  
Dual Fuel Combustion

High Pressure Direct-Injection (HPDI) is a technology option for engines used in mobile equipment applications where use of LNG as a fuel is desired. Using the combination of a diesel pilot injection and direct gas injection, HPDI has the potential to deliver low emissions, excellent transient performance, high efficiency, and high gas substitution. When the HPDI program was initially undertaken, in order to aid in initial hardware design, 3-dimensional computational fluid dynamic modeling was conducted to understand the mixing and reaction processes in the combustion chamber of an HPDI engine. Gaining insight into qualitative trends of operation parameters and hardware configurations was a first critical step toward delivering a hardware set to demonstrate HPDI natural gas combustion system capabilities. To model the combustion of multi-component fuel at arbitrary constituent ratios, a combustion model based on a detailed chemical kinetics approach was employed. Several published mechanisms and combinations of established mechanisms were tested by comparing results with existing fumigated dual fuel engine results. The result shows that some of combined mechanisms for n-heptane combustion and methane combustion are capable of adequately predicting combustion behavior in diesel-natural gas dual fuel combustion systems. One of the reduced n-heptane mechanisms (by Patel et al.) also matched dual fuel combustion results reasonably well. This preliminary simulation study was conducted with typical trapped air conditions and fuel quantities matching the energy delivery for a 100 % load condition in existing DI diesel engines. A full 360-degree mesh at intake valve closing was constructed and a detailed geometry of the gas injector nozzle and sac area was modeled in locally refined grids using a Caterpillar proprietary CFD code that accepts industry standard mechanisms. The diesel pilot injection followed by gas injection and resulting combustion inside an HPDI engine was simulated from IVC through the compression and combustion strokes. The operating parameters — such as diesel pilot injection timing, pilot injection amount, and start of gas injection — were varied, and the effect on IMEP, NOx, CO and cylinder pressure were investigated. It was shown that the start of gas injection is the strongest parameter for control of combustion. Subsequent to the work discussed in this paper, the hardware configuration established as optimal during the modeling work was carried forward to the physical engine testing and was successful in delivering the performance and emissions goals without modification, demonstrating the accuracy and value of modern combustion modeling.

Injector Tip Temperature and Combustion Performance of a Natural Gas-Diesel Dual Fuel Engine at Medium and High Load Conditions

2018 ◽  
Author(s):  
Hongsheng Guo ◽  
Brian Liko
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
High Load ◽  
Dual Fuel ◽  
Injection Timing ◽  
Combustion Engines ◽  
Combustion Performance ◽  
Diesel Injection ◽  
Dual Fuel Combustion ◽  
Load Conditions

Diesel engines have been widely used due to the higher reliability and superior fuel conversion efficiency. However, they still generate significant amount of carbon dioxide (CO2) and particulate matter (PM) emissions. Natural gas is a low carbon and clean fuel that generates less CO2 and PM emissions than diesel during combustion. Replacing diesel by natural gas in internal combustion engines help reduce both CO2 and PM emissions. Natural gas – diesel dual fuel combustion is a practical and efficient way to replace diesel by natural gas in internal combustion engines. One concern for dual fuel combustion engines is the diesel injector tip temperature increase with increasing natural gas fraction. This paper reports an experimental investigation on the diesel injector tip temperature variation and combustion performance of a natural gas – diesel dual fuel engine at medium and high load conditions. The natural gas fraction was changed from zero to 90% in the experiment. The results suggest that the injector tip temperature increased with increasing natural gas fraction at a given diesel injection timing or with advancing the diesel injection timing at a given natural gas fraction. However, the injector tip temperature never exceeded 250 °C in the whole experimental range. The effect of natural gas fraction on combustion performance depended on engine load and diesel injection timing.

scholarly journals A Numerical Study on the Combustion Process and Emission Characteristics of a Natural Gas-Diesel Dual-Fuel Marine Engine at Full Load

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1342
Author(s):  
Van Chien Pham ◽  
Jae-Hyuk Choi ◽  
Beom-Seok Rho ◽  
Jun-Soo Kim ◽  
Kyunam Park ◽  
...  
Keyword(s):  
Natural Gas ◽  
Combustion Process ◽  
Simulation Software ◽  
Dual Fuel ◽  
Injection Timing ◽  
Emission Characteristics ◽  
Cylinder Pressure ◽  
Marine Engine ◽  
Full Load ◽  
Simulation Results

This paper presents research on the combustion and emission characteristics of a four-stroke Natural gas–Diesel dual-fuel marine engine at full load. The AVL FIRE R2018a (AVL List GmbH, Graz, Austria) simulation software was used to conduct three-dimensional simulations of the combustion process and emission formations inside the engine cylinder in both diesel and dual-fuel mode to analyze the in-cylinder pressure, temperature, and emission characteristics. The simulation results were then compared and showed a good agreement with the measured values reported in the engine’s shop test technical data. The simulation results showed reductions in the in-cylinder pressure and temperature peaks by 1.7% and 6.75%, while NO, soot, CO, and CO2 emissions were reduced up to 96%, 96%, 86%, and 15.9%, respectively, in the dual-fuel mode in comparison with the diesel mode. The results also show better and more uniform combustion at the late stage of the combustions inside the cylinder when operating the engine in the dual-fuel mode. Analyzing the emission characteristics and the engine performance when the injection timing varies shows that, operating the engine in the dual-fuel mode with an injection timing of 12 crank angle degrees before the top dead center is the best solution to reduce emissions while keeping the optimal engine power.

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