Parametric Characterization of High-Pressure Diesel Fuel Injection Systems

2003 ◽  
Vol 125 (2) ◽  
pp. 412-426 ◽  
Author(s):  
T.-C. Wang ◽  
J.-S. Han ◽  
X.-B. Xie ◽  
M.-C. Lai ◽  
N. A. Henein ◽  
...  
Keyword(s):  
Ambient Pressure ◽  
Injection Pressure ◽  
Injection Rate ◽  
Common Rail ◽  
Rail Pressure ◽  
Electronic Unit ◽  
Rate Shaping ◽  
Common Rail Pressure ◽  
Nozzle Configuration

The focus of the study described herein is the characterization of the high-pressure hydraulic electronic unit injector (HEUI) and of the electronic unit injector (EUI) diesel injection systems. The characterization items include injection pressure, injection rate, injector response time, needle lift, start up injection transient, and dynamic discharge coefficient of the nozzles. Macroscopic and microscopic spray visualizations were also performed. The effects of injection conditions and nozzle configurations on injection characteristics were reviewed. Nozzle sac pressure was measured to correlate with the up-stream injection pressure. A LabVIEW data acquisition and controls system was implemented to operate the injection systems and to acquire and analyze data. For an HEUI system, based on the results of the study, it can be concluded that common-rail pressure and length of the injection rate-shaping pipe determine the injection pressure, while the pressure rising rate and injection duration determine the peak injection pressure; it was also found that the nozzle flow area, common-rail pressure, and the length of the rate-shaping pipe are the dominating parameters that control the injection rate, and the rate shape is affected mainly by common-rail pressure, especially the pressure rising rate and length of the rate-shaping pipe. Both injection pressure and ambient pressure affected the spray tip penetration significantly. The penetration increased corresponding to the increase of injection pressure or decrease of ambient pressure. The variation of spray penetration depends on the type of injection system, nozzle configuration, and ambient pressure. The large penetration variation observed on the HEUI sprays could be caused by eccentricity of the VCO (valve-covered-orifices) nozzle. The variation of the mini-sac nozzle was 50% less than that of the VCO nozzle. The near-field spray behavior was shown to be highly transient and strongly depended on injector design, nozzle configuration, needle lift and oscillation, and injection pressure.

On-Board Fuel Property Identification Method Based on High-Pressure Common Rail Pressure Signal

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Junfeng Zhao ◽  
Junmin Wang
Keyword(s):  
High Pressure ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Common Rail ◽  
Combustion Engines ◽  
Rail Pressure ◽  
Fuel Property ◽  
Pressure Signal ◽  
Common Rail Pressure ◽  
Property Identification

This paper investigates the impact of fuel property variations on the common rail pressure fluctuation in high-pressure common rail (HPCR) system and explores the possibility of identifying the fuel types based on the measurement of rail pressure for internal combustion engines. Fluid transients, particularly the water hammer effect in a HPCR system, are discussed and the 1D governing equations are given. A typical HPCR system model is developed in GT-Suite with the injectors, three-plunger high-pressure pump, and pressure control valve being modeled in a relatively high level of detail. Four different fuels including gasoline, ethanol, diesel, and biodiesel are modeled and their properties including density, bulk modulus, and acoustic wave speed are validated against data in the literature. Simulation results are obtained under different conditions with variable rail pressures and engine speeds. To reduce the excessive rail pressure oscillation caused by multiple injections, only four main-injections are enabled in each engine revolution. The results show that the natural frequency of a common rail varies with the type of fuel filled in it. By applying the fast Fourier transform (FFT) to the pressure signal, the differences of fuel properties can be revealed in the frequency domain. The experiment validation is conducted on a medium-duty diesel engine, which is equipped with a typical HPCR system and piezo-electric injectors. Tests results are given for both pure No. 2 diesel and pure soybean biodiesel at different rail pressure levels and different engine speeds. This approach is proved to be potentially useful for fuel property identification of gasoline-ethanol or diesel-biodiesel blends on internal combustion engines.

Comparison of Three Types of Common Rail Systems Suited for Diesel Engines From 1 to 5 Megawatt

2006 ◽  
Author(s):  
Marco Ganser ◽  
Ulrich Moser
Keyword(s):  
Diesel Engines ◽  
Pressure Wave ◽  
Dynamic Pressure ◽  
Injection Pressure ◽  
Injection Rate ◽  
Common Rail ◽  
Wave Dynamics ◽  
Rail Systems ◽  
Heavy Duty Diesel ◽  
The Individual

The basic physical law governing the injection in Common Rail Systems is the compressibility of the fuel. The effects of pressure wave dynamics, the layout of the system volume and its geometrical distribution strongly affect the injection events at every injector. In this Paper, three different arrangements of system volumes and their effect upon the performance of the individual injectors are compared using the hydraulics simulation tool AMESim. Two systems are known in the passenger car and the heavy duty diesel engine domains. The third system is new and takes advantage of pressure wave dynamics to tailor the injection event. This system is best suited for Diesel Engines with a power from 1 to 5 MW, as used in locomotives, ships, power generation and heavy earthmoving machinery. It produces a more favorable pattern of the injection pressure and injection rate shape during any injection event by hydraulically interconnecting the individual injector’s accumulators during the injection and taking advantage of pressure wave dynamics. Right after the end of each injection, dynamic pressure pulsations are evened out with a dampening device. A multi-cylinder system provides equal conditions for all injections. Its very simple design and increased performance makes the novel system of very attractive use in the above mentioned fields.

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