The Influence of Air-Fuel Ratio on Combustion Stability of a Gasoline Engine at Idle

1999 ◽  
Author(s):  
Sung Bin Han ◽  
Yon Jong Chung
Keyword(s):  
Gasoline Engine ◽  
Combustion Stability ◽  
Fuel Ratio

Tumble Flow Measurements Using Three Different Methods and Its Effects on Fuel Economy and Emissions

2006 ◽  
Author(s):  
Myoungjin Kim ◽  
Sihun Lee ◽  
Wootae Kim
Keyword(s):  
Fuel Economy ◽  
High Performance ◽  
Gasoline Engine ◽  
Exhaust Emissions ◽  
Combustion Stability ◽  
Lean Burn ◽  
Flow Measurements ◽  
Part Load ◽  
Gasoline Engines ◽  
Dynamometer Test

In-cylinder flows such as tumble and swirl have an important role on the engine combustion efficiencies and emission formations. In particular, the tumble flow, which is dominant in-cylinder flow in current high performance gasoline engines, has an important effect on the fuel consumptions and exhaust emissions under part load conditions. Therefore, it is important to know the effect of the tumble ratio on the part load performance and optimize the tumble ratio of a gasoline engine for better fuel economy and exhaust emissions. First step in optimizing a tumble flow is to measure a tumble ratio accurately. In this research the tumble flow was measured, compared and correlated using three different measurement methods: steady flow rig, 2-Dimensional PIV, and 3-Dimensional PTV. Engine dynamometer test was performed to find out the effect of the tumble ratio on the part load performance. Dynamometer test results of high tumble ratio engine showed faster combustion speed, retarded MBT timing, higher exhaust emissions, and a better lean burn combustion stability. Lean limit of the baseline engine was expanded from A/F=18:1 to A/F=21:1 by increasing a tumble ratio using MTV.

The effect of air/fuel ratio on the CO and NOx emissions for a twin-spark motorcycle gasoline engine under wide range of operating conditions

Energy ◽  
2019 ◽  
Vol 169 ◽  
pp. 1202-1213 ◽  
Author(s):  
Banglin Deng ◽  
Qing Li ◽  
Yangyang Chen ◽  
Meng Li ◽  
Aodong Liu ◽  
...  
Keyword(s):  
Gasoline Engine ◽  
Operating Conditions ◽  
Nox Emissions ◽  
Fuel Ratio ◽  
Wide Range

Effects of passive pre-chamber jet ignition on combustion and emission at gasoline engine

2021 ◽  
Vol 13 (12) ◽  
pp. 168781402110671
Author(s):  
Wei Duan ◽  
Zhaoming Huang ◽  
Hong Chen ◽  
Ping Tang ◽  
Li Wang ◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Gasoline Engine ◽  
Combustion Process ◽  
Pressure Rise ◽  
Spark Ignition ◽  
Combustion Stability ◽  
Intake Valve ◽  
Part Load ◽  
Significant Difference ◽  
Valve Opening

Pre-chamber jet ignition is a promising way to improve fuel consumption of gasoline engine. A small volume passive pre-chamber was tested at a 1.5L turbocharged GDI engine. Combustion and emission characteristics of passive pre-chamber at low-speed WOT and part load were studied. Besides, the combustion stability of the passive pre-chamber at idle operation has also been studied. The results show that at 1500 r/min WOT, compared with the traditional spark ignition, the combustion phase of pre-chamber is advanced by 7.1°CA, the effective fuel consumption is reduced by 24 g/kW h, and the maximum pressure rise rate is increased by 0.09 MPa/°CA. The knock tendency can be relieved by pre-chamber ignition. At part load of 2000 r/min, pre-chamber ignition can enhance the combustion process and improve the combustion stability. The fuel consumption of pre-chamber ignition increases slightly at low load, but decreases significantly at high load. Compared with the traditional spark ignition, the NOx emissions of pre-chamber increase significantly, with a maximum increase of about 15%; the HC emissions decrease, and the highest decrease is about 36%. But there is no significant difference in CO emissions between pre-chamber ignition and spark plug ignition. The intake valve opening timing has a significant influence on the pre-chamber combustion stability at idle operation. With the delay of the pre-chamber intake valve opening timing, the CoV is reduced and can be kept within the CoV limit.

scholarly journals Estimation of Individual Cylinder Air-Fuel Ratio in Gasoline Engine with Output Delay

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Changhui Wang ◽  
Zhiyuan Liu
Keyword(s):  
Gasoline Engine ◽  
Delay System ◽  
Exhaust Pipe ◽  
Gas Mixing ◽  
Fuel Ratio ◽  
Torque Generation ◽  
Output Delay ◽  
Reduce Emissions ◽  
The Individual ◽  
Balancing Control

The estimation of the individual cylinder air-fuel ratio (AFR) with a single universal exhaust gas oxygen (UEGO) sensor installed in the exhaust pipe is an important issue for the cylinder-to-cylinder AFR balancing control, which can provide high-quality torque generation and reduce emissions in multicylinder engine. In this paper, the system dynamic for the gas in exhaust pipe including the gas mixing, gas transport, and sensor dynamics is described as an output delay system, and a new method using the output delay system observer is developed to estimate the individual cylinder AFR. With the AFR at confluence point augmented as a system state, an observer for the augmented discrete system with output delay is designed to estimate the AFR at confluence point. Using the gas mixing model, a method with the designed observer to estimate the individual cylinder AFR is presented. The validity of the proposed method is verified by the simulation results from a spark ignition gasoline engine from engine software enDYNA by Tesis.

Research in Elman Neural Network for AFR Model of Automotive Engine

2011 ◽  
Vol 204-210 ◽  
pp. 755-759
Author(s):  
Yu Hong Bu
Keyword(s):  
Neural Network ◽  
Bp Neural Network ◽  
Gasoline Engine ◽  
Model Identification ◽  
Ratio Model ◽  
Power Performance ◽  
Elman Neural Network ◽  
Automotive Engine ◽  
Engine Model ◽  
Fuel Ratio

Air fuel ratio is a key index affecting power performance and fuel economy and exhaust emissions of the gasoline engine, whose accurate model is the foundation of accuracy air fuel ratio control. In the paper, at first, it has studied the Elman neural network (NN) simulation model of Air Fuel ratio physical model of automotive engine. Second, employing the SI-V8 in en-DYNA engine model as experimental device, the paper discussed the structure determination of Elman neural network; finally, it compared model identification performance between Elman and BP neural network. Experiment results show the generalization performance of neural network does not have a linear relationship to the neurons in hidden layer of Elman NN, and the air fuel ratio based on Elman neural network is better than the air fuel ratio model based on BP neural network. The average relative error of Elman NN air fuel ratio model is less than 0.5%, however, which of BP NN is more than 1%.

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