4^th Generation Diesel Common Rail System: Realizing Ideal Structure Function for Diesel Engine

Investigation on an Injection Strategy Optimization for Diesel Engines Using a One-Dimensional Spray Model

“…Figure 1 shows the schematic diagram of one-dimensional discrete diesel spray model. The fuel mass and axial momentum in each control volume are solved by the transport Equations (1) and (2).…”

“…Thus, the entrainment rate peak is decided by tEOI and UEOI. To calculate tEOI and UEOI under varying injection rate shapes, the Equation (14) proposed by Liu et al [11] is used in this paper: As discussed in the previous study [2], the velocity at the nozzle exit is high enough to affect the spray when the injection rate just begins to decrease for the ramping-down, triangle and trapezoid injection rates. Once the velocity at the nozzle exit is too low to affect the spray, the real time of the EOI (t EOI ) can be defined.…”

“…To cope with the emission problem and improve the performance of diesel engines, the common rail technology has flourished around the world. The advanced fuel injection technologies in a common rail system, such as the ultrahigh injection pressure [1][2][3][4] and the multiple-injection strategy [5][6][7] as well as the high control accuracy [8], have greatly improved the performance of diesel engines. Under the action of ultrahigh injection pressures, the fuel can be injected into the cylinder in a short time, while the multiple-injection strategy divides the whole injection duration into many parts, creating shorter injection durations.…”

Effects of valve needle speed on flow characteristics in control valve for unit pump fuel system

“…Comparing equation (2) with equation (3), the difference between the unsteady and the steady is Ð Dl (∂u=∂t)dl which is induced by the inertial force. According to Bernoulli's principle and the general continuity equation, we get the flow formula under the steady flow as follows where Q m is the mass flow rate, Cd is the discharge coefficient, Dp is the differential pressure between the inlet and the outlet, r is the density of the fluid, and A is the flow area.…”

“…These characteristics cause the inner flow within the control valve to be extremely complicated, and there is great turbulence, forming strong vortex and inducing cavitation. [2][3][4] Initially, the inner flow of the control valve may cause great pressure fluctuations and noise, vibrations, efficiency loss, and erosion damage on surfaces of the mechanical components that will reduce valve reliability and control precision. 5 Compounding these factors, the inner flow can cause abnormal hydrodynamic force resulting in erratic movement of the valve.…”