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Reducing emissions

Fuel mixture formation and combustion process

- Injection pressure;
- The time of injection;
- The spread of aerosol (room spray profile of the spray, the direction of the spray jet);
- Fuel injection timing;
- Movement of air;
- The amount of air.

These factors influence the release of pollutants and engine fuel consumption. The high combustion temperatures and high oxygen concentrations lead to increased formation of NOx. Isolation of carbon black is increased by reducing the amount of air and insufficient formation of the fuel mixture.

Criteria Engine

The configuration of the combustion chamber and the inlet channel may have a positive impact on reducing emissions of exhaust gases. If the movement of air in the combustion chamber is in accord with carefully fuel jet nozzles and that promotes efficient mixing of air and fuel is achieved the complete combustion of the injected fuel. Moreover, the beneficial effects are achieved homogenize the mixture of air and exhaust gas cooled in the EGR path. The use of four valves per cylinder and a turbocharger with variable turbine geometry (VTG) also helps to reduce emissions and increase power density.

Fuel injection timing

Reducing the combustion temperature, and slowing down the process of fuel injection leads to reduction of NOx in the exhaust gases. However, if these parameters are greatly reduced, increasing the HC content of exhaust gas and fuel consumption, as well as the selection of carbon black at high engine loads.

If the fuel injection timing deviates by only 1 ?� (crankshaft) from the optimum value, the NOx content can be increased by 5%, taking into account that the deviation is 2 ?� (crankshaft) in the direction of advancing the time of fuel injection may lead to an increase in pressure in the cylinders Engine 10 bar, and the deviation at 2 ?� (crankshaft) in the delay side can be increased by 20 ?� C exhaust gas temperature. This high sensitivity requires extreme precision in adjusting the fuel injection timing.

Fuel atomization

Microfine atomization of the fuel contributes to the efficient mixing of air and fuel. It makes a significant contribution to reducing the release of soot and HC. The high injection pressure and optimal geometric configuration sprayer holes lead to a good atomization of the fuel.

To eliminate the appearance of visible soot output fuel injection amount should be limited in accordance with the amount of air entering the engine. This requires the supply of excess air is at least 10 ... 40% (X = 1,1 ... 1,4). After closing the nozzle needle fuel remaining in the hole of the atomizer is vaporized and leads to an increase in HC discharge. This means that such harmful amounts should be minimized.