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Effective control measures for pollutants emitted by diesel generator sets (2)

June 06, 2022
In the previous article, we described the effective control measures for pollutant emissions from diesel generator sets from several steps of selecting a low-pollutant combustion system and improving the fuel supply system. In this article, we will continue to learn about other effective measures from other aspects. The emission of pollutants emitted by diesel generator sets can be controlled.
       3. Improve the intake system. The trend of diesel engine technology development is to increase the fuel injection pressure and reduce the intake swirl intensity to reduce the intake (pressure) loss, and to cooperate with the multi-hole and small-bore injectors to obtain a good mixture.
       The improvement of the intake system can be carried out in three ways:
       1) Adopt resonance air intake system. The general inertial charging system can only work in a narrow range of operating conditions of the diesel engine, while the variable resonance intake system can adjust the intake air volume in the entire speed range of full load and partial load.
       2) Adopt variable swirl air intake system. Since the intake swirl intensity has a great influence on NOx, the variable swirl intake system is used to control the swirl intensity according to the change of speed and load, which can reduce the amount of NOx generated without sacrificing economy.
       3) Adopt multi-valve technology. The use of multi-valve (4 valves per cylinder) can expand the total flow cross-sectional area of ​​the intake and exhaust valves, increase the charge coefficient, and the injector can be vertically arranged on the cylinder axis, which is conducive to the uniform distribution of fuel in the combustion chamber space, The mixture formation and combustion conditions are greatly improved, the heat release law is more reasonable, the NOx is reduced, the CO is also reduced, and the soot is also significantly reduced when the load is large.
       4. Adopt supercharging and intercooling technology. Because supercharging can improve diesel engine performance and reduce emissions, diesel engines will more commonly use exhaust gas turbocharging technology.
After the diesel engine is supercharged, the amount of CO and HC can be reduced due to the increased air density entering the cylinder. Without an intercooler, the amount of NOx emissions may increase due to the high intake air temperature. After using the intercooler, the intake air temperature can be reduced, so the NOx emission will decrease accordingly.
       5. Reduce the consumption of lubricating oil. Studies have shown that lubricating oil consumption has a significant impact on the size of diesel particulate emission limits. Therefore, the consumption of lubricating oil should be strictly controlled. The target is that the consumption of lubricating oil is less than 0.19g/kW·h under high load and high-speed operation conditions; When the oil gets particulate emission, the lubricating oil consumption is less than 0.5g/h×displacement (L). The control target of particulates generated from lubricating oil is not more than 0.0408 g/kw·h.
       Strategies to reduce lubricant particulate emissions include:
       1) Reduce the consumption of lubricating oil on the cylinder wall.
       2) Reduce the consumption of lubricating oil entering the combustion chamber and the supercharger.
       3) Develop low consumption lubricating oil.
       6. Adopt electronically controlled fuel injection technology. In order to meet the increasingly stringent emission regulations of diesel engines, electronic control of diesel engines has become an indispensable technology for diesel engines. The diesel engine adopts electronically controlled fuel injection technology to optimize the control of the fuel injection law and fuel injection quantity, and to control the fuel quantity of the premixed combustion and diffusion combustion parts. Pre-injection before main injection can effectively reduce NOx and noise, because pre-injection suppresses premixed combustion, delays diffusion combustion, and reduces the average gas temperature, so NOx generation is reduced.