Effects of Combustion Phasing, Relative Air-fuel Ratio, Compression Ratio, and Load on SI Engine Efficiency

2006 ◽  
Author(s):  
Ferrán A. Ayala ◽  
Michael D. Gerty ◽  
John B. Heywood
Keyword(s):  
Compression Ratio ◽  
Si Engine ◽  
Engine Efficiency ◽  
Fuel Ratio

scholarly journals A Numerical Analysis of the Effects of Equivalence Ratio Measurement Accuracy on the Engine Efficiency and Emissions at Varied Compression Ratios

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1413
Author(s):  
Ruomiao Yang ◽  
Xiaoxia Sun ◽  
Zhentao Liu ◽  
Yu Zhang ◽  
Jiahong Fu
Keyword(s):  
Compression Ratio ◽  
Thermal Efficiency ◽  
Equivalence Ratio ◽  
Measurement Accuracy ◽  
High Compression Ratio ◽  
Engine Efficiency ◽  
Fuel Ratio ◽  
High Compression ◽  
Performance And Emissions ◽  
Engine Stability

Increasingly stringent regulations to reduce vehicle emissions have made it important to study emission mitigation strategies. Highly accurate control of the air-fuel ratio is an effective way to reduce emissions. However, a less accurate sensor can lead to reduced engine stability and greater variability in engine efficiency and emissions. Additionally, internal combustion engines (ICE) are moving toward higher compression ratios to achieve higher thermal efficiency and alleviate the energy crisis. The objective of this investigation was to analyze the significance of the accuracy of air-fuel ratio measurements at different compression ratios. In this study, a calibrated 1D CFD model was used to analyze the performance and emissions at different compression ratios. The results showed that carbon monoxide (CO) and nitrogen oxides (NOx) were sensitive to the equivalence ratio regardless of the compression ratio. With a slight change in the equivalence ratio, a high compression ratio had little effect on the change in engine performance and emissions. Moreover, with the same air-fuel ratio, an excessively high compression ratio (CR = 12) might result in knocking phenomenon, which increases the fluctuation of the engine output parameters and reduces engine stability. Overall, for precise control of combustion and thermal efficiency improvement, it is recommended that the measurement accuracy of the equivalence ratio is higher than 1% and the recommended value of the compression ratio are roughly 11.

COMPUTATIONAL AND EXPERIMENTAL STUDIES OF A LOW-EMISSION BURNER FOR A PERSPECTIVE TURBOJET ENGINE WITH THE COMPRESSION RATIO EXCEEDING 40

2020 ◽  
Author(s):  
M. A. Danilov ◽  
◽  
M. V. Drobysh ◽  
A. N. Dubovitsky ◽  
F. G. Markov ◽  
...  
Keyword(s):  
Compression Ratio ◽  
Experimental Studies ◽  
The Other ◽  
Aircraft Engines ◽  
Engine Efficiency ◽  
Other Hand ◽  
Turbojet Engine ◽  
Low Emission ◽  
Civil Aircraft ◽  
The One

Restrictions of emissions for civil aircraft engines, on the one hand, and the need in increasing the engine efficiency, on the other hand, cause difficulties during development of low-emission combustors for such engines.

Comparing methods for improving spark-ignited engine efficiency: Over-expansion with multi-link cranktrain and high compression ratio with late intake valve closing

2020 ◽  
Vol 262 ◽  
pp. 114560 ◽  
Author(s):  
Zhuyong Yang ◽  
Niranjan Miganakallu ◽  
Tyler Miller ◽  
Jeremy Worm ◽  
Jeffrey Naber ◽  
...  
Keyword(s):  
Compression Ratio ◽  
Intake Valve ◽  
High Compression Ratio ◽  
Engine Efficiency ◽  
High Compression

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.

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