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Controlling fuel injection
Controlling the fuel injection can be made in the crankshaft position 90 ?� before TDC. If the start of fuel injection is made less than 40 ?� before TDC, fuel may deposit on the surface of the piston and cylinder walls and lead to undesirable dissolving it in the engine oil. In the control injection of a small amount of diesel fuel (1 ... 4 cm 3) is fed into the cylinder in the "pre-conventional" combustion chamber. The efficiency of fuel combustion can be improved to achieve the following effects: - Slight compression pressure to start the reaction, and incomplete combustion, which in turn, leads to: - ignition delay of the main injection;
- reduction of pressure in the combustion of fuel and smoothing the peaks of pressure (softer combustion).
These effects reduce the noise of the combustion, reduces fuel consumption and, in many cases, reduce emissions. In the case of discharge rates without controlling fuel injection in accordance with the compression takes place only a slight increase in pressure before TDC, which peaks sharply relative to the point of maximum pressure. A sharp increase in pressure in conjunction with a steep peak contributes significantly to the creation of noise during the combustion of fuel in a diesel engine. As shown on the curve with the unloading speed controlling injection pressure about TDC achieves a somewhat higher value, and the pressure increases at a slower rate. Since this reduces the ignition delay, control injection contributes indirectly to the formation torque. Specific fuel consumption may increase or decrease as a function of the main injection and the time between the control and the main fuel injection.  | The rise of the needle valve nozzle and the rate of discharge without controlling injection
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