Emissions Reduction Design And Test Research For YC4108ZLQ Diesel Engine

Exhaust emissions of vehicle is one of the important factors for environment pollution, and emissions of diesel vehicle stands in the breach. It's the fact that automobile emissions often occurred in the world make people attach importance to protect our atmospheric environment. Some countries have set down the statutes about exhaust emissions successively and made use of legislations to control atmospheric pollution. Currently purge technology for exhaust emissions control has come to the top and got fast developing in Europe, United States and Japan in which emission statutes were strictly put in practice, but technical difference in this aspect for our country is rather great. From 1998, some large cities in our country set down local statutes one after the other, restrict diesel vehicle into the city. But in recent years, with the rapid development of technology, many diesel engine manufacture corporations have used advanced technology and developed the diesel engine which can arrive at our country's emission standard, therefore the thing that restrict diesel vehicle into the city changed step by step. According to "Emission pollution control technical policy for diesel engine road vehicle"which is joint released by National General Bureau of Environmental Protection , National Committee for Economic and Trade and the Technology Office before long, our country's exhaust emission for diesel engine road vehicle should arrive at Europe II emission standard in 2004, and will try our best to arrive at Europe III emission standard in 2008, then try to reach international emission control level after 2010. In fact some main cities in our country have put in practice Europe II emission standard in 2003, and will put ahead in practice Europe III emission standard in 2005. Control vehicle emissions, reduce atmospheric pollution and develop exhaust purge technology is still one of the biggest research tasks in the future. In the light of national layout requirement for relational industry policy, in order to meet the demand of future market, YC4108ZLQ diesel engine this paper researched is the new production which is improved and developed by themselves of Yuchai Machinery Co. Ltd. in Guangxi in 2003, which is based on the YC4108ZQ diesel engine which steadily arrived at Europe I emission standard. The engine's main design guideline: Rated Power is 96KW/2800r/min, its emission level arrives at Europe II standard. In order to meet design requirements, and make its emission level arrive at Europe II standard, YC4108ZLQ diesel engine mainly adopts the technical measures as follow: 1. Make use of supercharging, air-air inter-cooling technology. Turbo shell parameter: A/R is 0.49, compressor shell parameter: A/R is 0.42. 2. Improve the fuel supply system. High pressure fuel pump uses PN pump. The pump working ability is between AD pump and P type pump. Relative to AD pump, its rate of fuel supply is quickened a little to shorten fuel supply duration angles, and its pump-end working pressure is increased a little to improve pulverization quality of fuel. To increase the rate of fuel injection can reduce the increase of CO and HC which arose because of the delay of fuel injection timing. Fuel injector is P type without pressure chamber volume. To reduce pressure chamber volume is able to lower the emission of HC. 3. Combustion chamber design. D. I. ωshrink type combustion chamber is used to suit the intake swirl and fuel spray reasonably. The design of combustion chamber impresses on gas flowing, mixing fuel with gas and combustion speed, therefore matching tests with kinds of schemes are made to get better power, economy andemission guideline. 4. Oil consumption is reduced to decrease the particle PM emission. 1) To decrease the oil consumption, mesh construction parameter for cylinder liner flat must be improved, the parameter of mesh deep and angle also must be designed reasonably. 2) The rigidity design which makes the cylinder block and cylinder liner stronger is used to decrease the distortion of cylinder liner. 3) Matching clearance and section shape of piston ring must be optimized to improve its laying oil and razing oil ability. 4) Matching clearance between piston and cylinder liner is optimized to improve oil circle measure, thus the oil can return to oil pan quickly. 5. Valve train improvement. Improving the cam profile and increasing the cam maximal lift can add the time-area of the valve and charge more air. To avoid the valve abdication hole on piston top too deep(even without opening), and to avoid the exhaust gas of engine flow return in low speed and low load ,valve timing is improved. Performance experiment and emissions test for YC4108ZLQ diesel engine is made in workbench, and the factors which affect emissions as follow are contrasted by experiment and analysis: 1. Influence on emission of fuel supply advance angle. Test results show that reducing the fuel supply advance angle, i.e., retarding the fuel supply advance angle is one of the effective measures which can reduce NOX emission of diesel engine. But reducing the fuel supply advance angle will make PM emission increase. 2. Influence on emission of intake pressure. Within the range of proper intake pressure, preferable integrated emission guideline can obtain, emissions guideline will occur different variety out of the range. If intake pressure is too low, and all kinds of emissions will increase; if intake pressure is too high, CO and HC emission will go up.3. Influence of combustion chamber on emission. Combustion chamber design will influence greatly on gas flow, fuel-air mixture and combustion. The shallow combustion chamber that its caliber is properly increase and use multi-hole nozzle with small aperture can get preferable dynamics, economy and emission guideline. 4. Influence of pressure chamber volume of fuel injector on emission. Pressure chamber volume influences greatly on HC emission, To reduce the pressure chamber volume can decrease HC emission. By technical improvement and relevant adjustable parameters are optimally selected, test results in workbench showed that the power and economy guideline for YC4108ZLQ diesel engine meet the design requirement, and its emissions arrive at Europe II standard .