Non-road Euro ¢ò Emission Single Cylinder Diesel Engine Research

With the increasing shortage of fossil oil, aggravation of environmental pollution and human health, as well as stringent exhaust emission standards, single cylinder diesel engine which have been widely used in agricultural machinery should be developed friendly to environment, namely we should put more emphasis study on its pollution control now.This paper contains a series of studies, improvements and experimental work of the single-cylinder diesel engines'structure and parameters to meet EuroⅡemission standards. The study, high-power models ZS1115 as research object, develop a new generation-that is ZS1115H environmental models-to reach EuroⅡemission limits by improving combustion system, intake and exhaust systems, fuel injection system and so on. Based on lessons learned from this study, the gradual improvement to other models and the upgrading of ZS Series models are achieved. The determination that the combustion chamber type is thick mouth, big boss-type reentrantωis based on the analysis of air movement within the cylinder. Reducing the intake swirl ratio appropriately, and increasing the piston's compression vortex, squish and reverse squish and so on make the mixture formation and combustion more complete. At the same time, adjust the gap between piston and cylinder, and the size and shape of the piston rings to reduce oil consumption and lower emissions of CH and particulate. Airway inlet spiral, the reduction of the intake swirl according to the combustion chamber and the improvement of the flow coefficient make the gas mixture more uniform, while reducing the burning speed decreases the maximum combustion temperature and reduces NOx emissions. Improve fuel injection pressure and injection rate by optimizing the factors which affect the fuel injection system, using low-inertia small pressure chamber "P"-type injector instead of "S" series fuel injectors, and replacing the AD pump with DP pump. Reduce the initial injection rate and the pre-mixed combustion temperature to reducing NOx emissions. In the diffusion combustion period, increasing fuel injection rate to ensure adequate fuel injected into the combustion chamber, to achieve rapid combustion in order to reduce soot and particulate emissions. At the premise of ensuring economy, adjust the fuel injection timing to minimize the fuel injection timing, shorten ignition delay and reduce the cylinder pressure of the combustion diffusion and temperature rise rate, to reduce the amount of pollutants and noise in order to achieve the purpose of energy saving engine. Test results show:the new designs of the fuel system, intake and exhaust system, and combustion system, while improving the injection pressure, reducing the fuel supply advance angle, taking the appropriate combustion chamber swirl ratio and increasing the role of squeeze flow, taking the new section piston shape and increasing the combustion chamber sealing, to optimize the engine working process and reduce the fuel consumption and oil consumption effectively, so that make the combustion more reasonable and full, and effectively control CH, NOx and soot formation. Reduce emissions of exhaust pollutants with a slight increasing overall performance over the current level. A series of measures such as improving piston assembly and fuel system and achieving the best match of inlet, injection rate and combustion system have greatly improved the engine power and economy. At the same time, other contaminants of new models successfully achieve the European II emission standard in addition particles, and a greater degree of well-off exits, to ensure consistency of the model to meet the EuropeanⅡemission standard in the mass production. The successful development of diesel engine ZS1115H as the start of single-cylinder diesel engine's improving, lay a solid foundation for the single-cylinder diesel engine industry to adapt to the modern development trends in energy saving and the improvement of product quality, and provide ideas and approach to design, which will have a far-reaching impact on the healthy development of single-cylinder diesel engine industry.