Effects of Fuel Composition on In-Cylinder Air/Fuel Ratio During Fuelling Transients in an SI Engine, Measured Using Differential Infra-Red Absorption

1996 ◽  
Author(s):  
S. M. Skippon ◽  
S. R. Nattrass ◽  
J. S. Kitching ◽  
L. Hardiman ◽  
H. Miller
Keyword(s):  
Fuel Composition ◽  
Si Engine ◽  
Fuel Ratio ◽  
Infra Red

Analysis of Water–Fuel Ratio Variation in a Gas Turbine With a Wet-Compressor System by Change in Fuel Composition

2017 ◽  
Vol 140 (5) ◽  
Author(s):  
Yonatan Cadavid ◽  
Andres Amell ◽  
Juan Alzate ◽  
Gerjan Bermejo ◽  
Gustavo A. Ebratt
Keyword(s):  
Gas Turbine ◽  
Burning Velocity ◽  
Thermal Power ◽  
Flame Temperature ◽  
Fuel Composition ◽  
Nox Formation ◽  
Gaseous Hydrocarbon ◽  
Power Generators ◽  
Fuel Ratio ◽  
Combustion Properties

The wet compressor (WC) has become a reliable way to reduce gas emissions and increase gas turbine efficiency. However, fuel source diversification in the short and medium terms presents a challenge for gas turbine operators to know how the WC will respond to changes in fuel composition. For this study, we assessed the operational data of two thermal power generators, with outputs of 610 MW and 300 MW, in Colombia. The purpose was to determine the maximum amount of water that can be added into a gas turbine with a WC system, as well as how the NOx/CO emissions vary due to changes in fuel composition. The combustion properties of different gaseous hydrocarbon mixtures at wet conditions did not vary significantly from each other—except for the laminar burning velocity. It was found that the fuel/air equivalence ratio in the turbine reduced with lower CH4 content in the fuel. Less water can be added to the turbine with leaner combustion; the water/fuel ratio was decreased over the range of 1.4–0.4 for the studied case. The limit is mainly due to a reduction in flame temperature and major risk of lean blowout (LBO) or dynamic instabilities. A hybrid reaction mechanism was created from GRI-MECH 3.0 and NGIII to model hydrocarbons up to C5 with NOx formation. The model was validated with experimental results published previously in literature. Finally, the effect of atmospheric water in the premixed combustion was analyzed and explained.

scholarly journals Adaptive Air-Fuel Ratio Regulation for Port-Injected Spark-Ignited Engines Based on a Generalized Predictive Control Method

Energies ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 173 ◽  
Author(s):  
Lei Meng ◽  
Xiaofeng Wang ◽  
Chunnian Zeng ◽  
Jie Luo
Keyword(s):  
Predictive Control ◽  
Noise Suppression ◽  
Control Method ◽  
Simulation Analysis ◽  
Catalytic Converter ◽  
Exhaust Emission ◽  
Generalized Predictive Control ◽  
Si Engine ◽  
Fuel Ratio ◽  
Wall Wetting

The accurate air-fuel ratio (AFR) control is crucial for the exhaust emission reduction based on the three-way catalytic converter in the spark ignition (SI) engine. The difficulties in transient cylinder air mass flow measurement, the existing fuel mass wall-wetting phenomenon, and the unfixed AFR path dynamic variations make the design of the AFR controller a challenging task. In this paper, an adaptive AFR regulation controller is designed using the feedforward and feedback control scheme based on the dynamical modelling of the AFR path. The generalized predictive control method is proposed to solve the problems of inherent nonlinearities, time delays, parameter variations, and uncertainties in the AFR closed loop. The simulation analysis is investigated for the effectiveness of noise suppression, online prediction, and self-correction on the SI engine system. Moreover, the experimental verification shows an acceptable performance of the designed controller and the potential usage of the generalized predictive control in AFR regulation application.

Influence of Air/Fuel Ratio on Cyclic Variation and Exhaust Emission in Natural Gas SI Engine

1999 ◽  
Author(s):  
Livier Ben ◽  
Nathalie Raud-Ducros ◽  
Remy Truquet ◽  
Georges Charnay
Keyword(s):  
Natural Gas ◽  
Exhaust Emission ◽  
Cyclic Variation ◽  
Si Engine ◽  
Fuel Ratio

scholarly journals Air/Fuel Ratio Estimation of SI Engine Using Higher Order Sliding Mode

2013 ◽  
Vol 46 (21) ◽  
pp. 501-506 ◽  
Author(s):  
Muhammad Amin Akram ◽  
Aamer Iqbal Bhatti ◽  
Qadeer Ahmed
Keyword(s):  
Sliding Mode ◽  
Higher Order ◽  
Ratio Estimation ◽  
Si Engine ◽  
Fuel Ratio

Air-Fuel Ratio Control of Spark Ignition Engines With TWC Using LPV Techniques

2009 ◽  
Author(s):  
Rohit A. Zope ◽  
Javad Mohammadpour ◽  
Karolos M. Grigoriadis ◽  
Matthew Franchek
Keyword(s):  
Design Method ◽  
Spark Ignition ◽  
Operating Conditions ◽  
System Stability ◽  
Linear Matrix ◽  
Pi Control ◽  
Spark Ignition Engines ◽  
Si Engine ◽  
Precise Control ◽  
Fuel Ratio

Precise control of the air-fuel ratio in a spark ignition (SI) engine is important to minimize emissions. The emission reduction strongly depends on the performance of the air-fuel ratio controller for the SI engine in conjunction with the Three Way Catalytic (TWC) converter. The TWC converter acts as a buffer to any variations occurring in the air-fuel ratio. It stores oxygen during a lean operation and releases the stored oxygen during a rich transient phase. The stored oxygen must be maintained close to the current storage capacity to yield maximum benefits from the TWC converter. Traditionally this is achieved using a simple PI control or a gain-scheduled PI control to address the variability in the operating conditions of the engine. This, however, does not guarantee closed-loop system stability and/or performance. In this work a model-based linear parameter varying (LPV) approach is used to design an H∞ controller. The design goal is to minimize the effect of disturbances on the air-fuel ratio and hence the relative storage level of oxygen in the TWC, over a defined operating range for the SI engine. The design method formulated in terms of Linear Matrix Inequalities (LMIs) leads to a convex optimization problem which can be efficiently solved using existing interior-point optimization algorithms. Simulations performed validate the proposed control design methodology.

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