Maintaining Low Exhaust Emissions With Turbocharged Gas Engines Using a Feedback Air–Fuel Ratio Control System

1987 ◽  
Vol 109 (4) ◽  
pp. 487-490 ◽  
Author(s):  
D. W. Eckard ◽  
J. V. Serve´
Keyword(s):  
Control System ◽  
Temperature Control ◽  
Exhaust Emissions ◽  
Ambient Conditions ◽  
Load Range ◽  
Heating Value ◽  
Gas Engine ◽  
Precise Control ◽  
Natural Gas Engine ◽  
Fuel Ratio

Maintaining low exhaust emissions on a turbocharged, natural gas engine through the speed and load range requires precise control of the air–fuel ratio. Changes in ambient conditions or fuel heating value will cause the air–fuel ratio to change substantially. By combining air–gas pressure with preturbine temperature control, the air–fuel ratio can be maintained regardless of changes in the ambient conditions or the fuel’s heating value. Design conditions and operating results are presented for an air–fuel controller for a turbocharged engine.

Design and Experimental Study of Deposition Temperature Control System in Ultra-High Vacuum

2012 ◽  
Vol 571 ◽  
pp. 564-568
Author(s):  
Zhi Dan Yan ◽  
Li Dong Sun ◽  
Chun Guang Hu ◽  
Xiao Tang Hu ◽  
Peter Zeppenfeld
Keyword(s):  
Control System ◽  
Temperature Control ◽  
Deposition Temperature ◽  
Film Growth ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Temperature Control System ◽  
Growth Morphology ◽  
Precise Control ◽  
Key Factor

Deposition temperature is a key factor influencing the growth morphology of thin-films, aiming at this phenomenon, a precise control system of deposition temperature in ultra-high vacuum is developed in the paper. It can realize accurate temperature control in a range of 150K to 450K during experiment by combination of resistance heating up and liquid helium cooling down strategies, which is benefit to further understand the temperature-depended mechanism of organic molecule thin-film growth. Besides, it is experimentally studied that the growth morphology of p-6p molecules on a mica substrate is closely related to the substrate deposition temperature, indicating that the length of p-6p nano-fibers is proportional to the deposition temperature, while their distribution density is inversely proportional to the temperature.

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.

Selective NOx Recirculation for Stationary Lean-Burn Natural Gas Engines

2004 ◽  
Author(s):  
Chamila A. Tissera ◽  
Matt M. Swartz ◽  
Emre Tatli ◽  
Ramprabhu Vellaisamy ◽  
Nigel N. Clark ◽  
...  
Keyword(s):  
Natural Gas ◽  
Combustion Process ◽  
Injection System ◽  
Lean Burn ◽  
Desorption Process ◽  
Gas Engine ◽  
No Conversion ◽  
Natural Gas Engine ◽  
Fuel Ratio ◽  
Conversion Rates

NOx control in a lean burn natural gas engine is typically achieved with appropriate management of air/fuel ratio and ignition timing. A novel approach for further reduction involves the capture of NOx by first adsorbing the NOx from the exhaust stream, followed by the periodic desorption of NOx from an aftertreatment medium. Then, by passing the desorbed NOx gas into the intake air stream and back through the engine, a percentage of the NOx will be converted to harmless gases during the combustion process. The objective of this paper is to report the NOx conversion phenomenon during a lean combustion process. The results of this testing will be used to develop an optimal system for the conversion of NOx with a NOx adsorber. A 1993 Cummins L10-G spark ignited natural gas engine was used to conduct the experiments. Commercially available nitric oxide (NO, 98.8% purity) was injected into the engine intake to mimic the NOx stream from the desorption process to obtain NO conversion rates at various steady-state engine operating points. The NO injection system was capable of injecting NO at varying flow rates and time intervals. NO was injected into the intake manifold for ten and twenty second periods, and the conversion rates were calculated. When the injected NO amount increased from 0.22 g/s to 1.2 g/s and engine loads varied from 200ft-lb to 400ft-lb at 800 RPM, the NO conversion rates increased from 5% to 47%. It was observed that the air/fuel ratio, injected NO quantity and the engine load greatly effected the NO conversion rates. It was also noted that engine speed had a negligible affect when the intake NO concentration was held constant.

Improvement of Performance and Exhaust Emissions in a Converted Dual-Fuel Natural Gas Engine

2000 ◽  
Author(s):  
Takuji Ishiyama ◽  
Masahiro Shioji ◽  
Shin-ichi Mitani ◽  
Hiroaki Shibata ◽  
Makoto Ikegami
Keyword(s):  
Natural Gas ◽  
Exhaust Emissions ◽  
Dual Fuel ◽  
Gas Engine ◽  
Natural Gas Engine

Analysis of Exhaust Emissions of Natural Gas Engine by Using Response Surface Methodology

2008 ◽  
Vol 8 (19) ◽  
pp. 3328-3339 ◽  
Author(s):  
R. Saidur ◽  
M.I. Jahirul ◽  
M. Hasanuzzam ◽  
H.H. Masjuki
Keyword(s):  
Response Surface Methodology ◽  
Natural Gas ◽  
Response Surface ◽  
Exhaust Emissions ◽  
Gas Engine ◽  
Natural Gas Engine
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