Analysis Research of Technology Schemes of Reduction NOx Emission in Lean Burn Gasoline Engine

2013 ◽  
Vol 724-725 ◽  
pp. 1454-1458
Author(s):  
Dong Peng Yue ◽  
Wen Zhang ◽  
Zhi Jun Li ◽  
Ying Zhang ◽  
Lei Liu ◽  
...  

The lean burn technology has been paid attention recently by more and more people because the economics and emission of the gasoline engine can been improved extensively by lean burn technology. However, the reduction of NOx emission is quite small because of the rich oxygen. The different combination schemes of NOx adsorber and Three Way Catalyst were adopted in this paper and experiments of reduction NOx emission have been studied in an modified EFI 16 valves lean burn gasoline engine . The experiment results show that the scheme of the position of Three Way Catalyst is before the NOx adsorber Catalyst was the best scheme of reduction NOx emission in lean burn gasoline engine.

Author(s):  
Zhengmao Ye ◽  
Zhijun Li ◽  
Habib Mohamadian

A novel catalyst converter system has been developed for NOx emission aftertreatment of lean burn gasoline engines. The goal is to investigate its impact on emission characteristic and Break Specific Fuel Consumption (BSFC) across a wide range of engine speed and load operating regions, subject to several arrangement schemes for this catalyst converter. It has been indicated from experimental results that the upstream placement of TWC (Three Way Catalyst) ahead of the NOx Adsorber Catalyst is the best solution, which gives rise to the highest converting efficiency to reduce the NOx emission level of the lean burn gasoline engine. The effects of engine speed on exhaust emissions and BSFC are also reflected by operating time of lean mode and rich mode as well as the time ratio between the two using adsorber-reduction catalyst converters. Engine load is in fact the major factor in affecting exhaust characteristics and BSFC of lean burn engines.


Author(s):  
Martyn V Twigg

Photochemical reactions of vehicle exhaust pollutants were responsible for photochemical smog in many cities during the 1960s and 1970s. Engine improvements helped, but additional measures were needed to achieve legislated emissions levels. First oxidation catalysts lowered hydrocarbon and carbon monoxide, and later nitrogen oxides were reduced to nitrogen in a two-stage process. By the 1980s, exhaust gas could be kept stoichiometric and hydrocarbons, carbon monoxide and nitrogen oxides were simultaneously converted over a single ‘three-way catalyst’. Today, advanced three-way catalyst systems emissions are exceptionally low. NO x control from lean-burn engines demands an additional approach because NO cannot be dissociated under lean conditions. Current lean-burn gasoline engine NO x control involves forming a nitrate phase and periodically enriching the exhaust to reduce it to nitrogen, and this is being modified for use on diesel engines. Selective catalytic reduction with ammonia is an alternative that can be very efficient, but it requires ammonia or a compound from which it can be obtained. Diesel engines produce particulate matter, and, because of health concerns, filtration processes are being introduced to control these emissions. On heavy duty diesel engines the exhaust gas temperature is high enough for NO in the exhaust to be oxidised over a catalyst to NO 2 that smoothly oxidises particulate material (PM) in the filter. Passenger cars operate at lower temperatures, and it is necessary to periodically burn the PM in air at high temperatures.


2007 ◽  
Author(s):  
Zhijun Li ◽  
Zhengmao Ye ◽  
Habib Mohamadian ◽  
Ying Zhang ◽  
Xiaoming Sun ◽  
...  

Lean burn gasoline direct injection (GDI) engines are the most preferred gasoline engines because of their low fuel consumption and high thermal efficiency. However, these engines produce exhaust gases that are particularly rich in oxygen and therefore the present three-way catalytic converter (TWC) is not suitable for converting the generated NOX emission into Nitrogen gases. In this present work, a new method of reducing Nitrogen Oxides emission in a gasoline engine is attempted by using an ordinary oxidation catalyst together with a deNOX(zeolite-based) catalyst. In this work, Na-form of ZSM-5 zeolite was used as a catalyst and cupric chloride (CuCl2) and ferric chloride (FeCl3) where used as transition metals. Cu-ZSM5 and Fe-ZSM5 catalyst were prepared separately in our laboratory. Na+ ion exchange method is used to prepare the catalyst. After that Cu-ZSM% and Fe- ZSM5 catalyst were washcoated separately onto the blank monoliths. Oxidation monoliths ( for oxidation of CO and HC into CO2 and H2O) were purchased directly from market. One oxidation monolith and one zeolite coated monolith were placed in a stainless steel container and canned with inlet and outlet cones ( forming catalytic convertor ). Experiments were conducted on a 2 cylinder Multi Point Port Fuel Injection engine along with a dynamometer. Exhaust emissions such as NOX, CO, HC, O2, CO2 were measured with AVL Di-gas-444 Analyzer. Exhaust gas temperature is measured with the use of a thermocouple. Firstly load tests (4, 7, 10, 13, and 16KW) were conducted on the engine without catalytic convertor was fixed close to the outlet pipe and the test were conducted again with same loading condition as mentioned above. Then by the same above procedure is followed to conduct test with Cu-ZSM5 and Fe-ZSM5 catalytic convertors. From the results it is observed that both Cu and Fe zeolite catalyst minimize emissions than the commercial catalytic converter.


Lean burn gasoline direct injection (GDI) engines are the most preferred gasoline engines because of their low fuel consumption and high thermal efficiency. However, these engines produce exhaust gases that are particularly rich in oxygen and therefore the present three-way catalytic converter (TWC) is not suitable for converting the generated NOX emission into Nitrogen gases. In this present work, a new method of reducing Nitrogen Oxides emission in a gasoline engine is attempted by using an ordinary oxidation catalyst together with a deNOX(zeolite-based) catalyst. In this work, Na-form of ZSM-5 zeolite was used as a catalyst and cupric chloride (CuCl2 ) and ferric chloride (FeCl3 ) where used as transition metals. Cu-ZSM5 and Fe-ZSM5 catalyst were prepared separately in our laboratory. Na+ ion exchange method is used to prepare the catalyst. After that Cu-ZSM% and Fe- ZSM5 catalyst were washcoated separately onto the blank monoliths. Oxidation monoliths ( for oxidation of CO and HC into CO2 and H2O) were purchased directly from market. One oxidation monolith and one zeolite coated monolith were placed in a stainless steel container and canned with inlet and outlet cones ( forming catalytic convertor ). Experiments were conducted on a 2 cylinder Multi Point Port Fuel Injection engine along with a dynamometer. Exhaust emissions such as NOX, CO, HC, O2 , CO2 were measured with AVL Di-gas-444 Analyzer. Exhaust gas temperature is measured with the use of a thermocouple. Firstly load tests (4, 7, 10, 13, and 16KW) were conducted on the engine without catalytic convertor was fixed close to the outlet pipe and the test were conducted again with same loading condition as mentioned above. Then by the same above procedure is followed to conduct test with Cu-ZSM5 and Fe-ZSM5 catalytic convertors. From the results it is observed that both Cu and Fe zeolite catalyst minimize emissions than the commercial catalytic converter.


Author(s):  
Myoungjin Kim ◽  
Sihun Lee ◽  
Wootae Kim

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.


Sign in / Sign up

Export Citation Format

Share Document