Reduced Cold-Start Emissions Using Rapid Exhaust Port Oxidation (REPO) in a Spark-Ignition Engine

1997 ◽  
Author(s):  
Michael E. Crane ◽  
Robert H. Thring ◽  
Daniel J. Podnar ◽  
Lee G. Dodge
Author(s):  
Makoto Koike ◽  
Tetsunori Suzuoki ◽  
Tadashi Takeuchi ◽  
Takayuki Homma ◽  
Satoshi Hariu ◽  
...  

2019 ◽  
Vol 22 (1) ◽  
pp. 184-198
Author(s):  
Mikiya Araki ◽  
Katsuya Sakairi ◽  
Takashi Kuribara ◽  
Juan C González Palencia ◽  
Seiichi Shiga ◽  
...  

In a four-stroke cycle port-fuel-injected spark-ignition engine, a significant portion of unburned hydrocarbons is exhausted during the short period of cold start. The aim of this study is to investigate the physics behind the wall-wet phenomena and its determining parameter as simply as possible even though qualitative to some extent. The test engine is driven at a constant speed of 350 r/min. The fuel injection starts at a certain cycle, and the cycles required for the first ignition is counted. Three gasoline injectors having different atomization characteristics are used for port fuel injection, and the droplet size, the spray angle and the spray velocity are varied independently. The fuel transport phenomena from the injector to the cylinder are characterized by only two parameters, α and β, the mass fraction of the fuel without wall-wet and the mass fraction of the evaporated fuel from liquid films on walls. They are determined so that all the first ignition cycles observed experimentally are consistently reproduced by the model. The value of α is successfully determined for every single injector, and it increases monotonously with the decrease in the Stokes number.


Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1330 ◽  
Author(s):  
Nguyen Xuan Khoa ◽  
Ocktaeck Lim

In this research, the residual gas, peak firing pressure increase, and effective release energy were completely investigated. To obtain this target, the experimental system is installed with a dynamo system and a simulation model was setup. Through combined experimental and simulation methods, the drawbacks of the hardware optimization method were eliminated. The results of the research show that the valve port diameter-bore ratio (VPD/B) has a significant effect on the residual gas, peak firing pressure increase, and effective release energy of a four-stroke spark ignition engine. In this research, the engine was performed at 3000 rpm and full load condition. Following increased IPD/B ratio of 0.3–0.5. The intake port and exhaust port diameter has a contrary effect on engine volumetric efficiency, the residual gas ratio increase 27.3% with larger intake port and decrease 18.6% with larger exhaust port. The engine will perform optimal thermal efficiency when the trapped residual gas fraction ratio is from 13% to 14%. The maximum effective release energy was 0.45 kJ at 0.4 intake port-bore ratio, and 0.451 kJ at 0.35 exhaust port-bore ratio. The NOx emission increases until achieved a maximum value after that decrease even VPD/B was still increasing. With a VPD/B ratio of 0.35 to 0.4, the engine works without the misfiring.


2014 ◽  
Vol 977 ◽  
pp. 47-50
Author(s):  
Mei Yu Shi ◽  
Rong Fu Zhu ◽  
Jiang Li ◽  
Yuan Tao Sun

The influence of butanol/gasoline blends at low temperature for-7°C, on cold-start emissions of a spark-ignition engine was tested. In cold-start period of the engine, the efficiency of the engine was expected to be poor, and the air/fuel mixture would be leaner for the more butanol added. The experimental results showed that the engine could be stable with B10 and B30 in cold-start, and HC and CO emissions reduced more significantly with more butanol added.


2014 ◽  
Vol 555 ◽  
pp. 375-384 ◽  
Author(s):  
Stelian Tarulescu ◽  
Adrian Soica

This paper present a study regarding the emissions produced at the engine cold start. Also, the paper presents a brief survey of current extra emissions estimation methods. The main goal of this work is to describe the relative cold start extra emissions as a function of exhaust gas temperature. Experimental research has been done for a light vehicle, Dacia Sandero, equipped with a 1390 cm3 Renault spark ignition engine (Power = 55 kW at 5500 rpm). There were been made several tests, in different temperature conditions, in the could season, using a portable analyzer, GA-21 plus (produced by Madur Austria). The parameters measured with the analyzer and used in the analysis are: CO, NO, NOx and SO2. It was concluded that the highest pollutants values ​​are recorded until the point when the catalyst comes into operation (when the gas temperature entering the catalyst is approx. 200 oC) and exhaust gas temperature is 40-50 oC. In order to accomplish a mathematical approximation of CO, NO and SO2 in function of exhaust gas temperature, logarithmic approximations and polynomial regressions were used. The curves resulted from the mathematical model can be used to approximate the level of CO, NO and SO2, for similar vehicles.


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