Matched Impedance to Control Fluid Transients

1983 ◽  
Vol 105 (2) ◽  
pp. 219-224 ◽  
Author(s):  
S. J. Wright ◽  
E. B. Wylie ◽  
L. B. Taplin

A methodology for the use of passive elements for transient control in pipelines is outlined. The specific objective is the elimination of pressure fluctuations in a fuel delivery line that are created by fuel injector operation. This is accomplished by the appropriate sizing of resistance elements upstream and downstream of the fuel injection system in the delivery line such that no pressure wave reflections occur in the system. The concept of matching the resistance element to the characteristic impedance of the fuel delivery system is described and applied to orifice and laminar flow elements. Experimental evidence is presented to validate the concepts.

1991 ◽  
Vol 113 (1) ◽  
pp. 143-151 ◽  
Author(s):  
W. C. Yang ◽  
J. M. Glidewell ◽  
W. E. Tobler ◽  
G. K. Chui

A dynamic model of a multi-port electronic fuel injection system, capable of analyzing fast fluid transients in the fuel, is presented. The model consists of distributed parameter models for fuel lines and lumped parameter models for the fuel pump, pressure regulator and injectors. Modal approximation is used to model fuel lines. An experimental test bench has been established, and comparison of simulation and experimental results shows excellent agreement in transient characteristics. Using this experimentally verified model, the effects of injector clogging and vapor in the fuel rail on pressure transients are examined. A bond graph model of the total system is presented to identify the proper formulation of each subsystem model.


Author(s):  
John M. Gattoni ◽  
David M. Sykes ◽  
Paul E. Yelvington

Using the latest manufacturing technology and patented nozzle geometry, an innovative high-speed (two or more injections at an engine operating speed of 6,000 RPM), lightweight fuel injection system was developed that controls supercavitation within the fuel injector nozzle. The patented supercavitating fuel injector nozzle reduces the penetration length of the fuel spray by 25–30%, average droplet size by 15.5% when operating at the same fuel pressure, and improves droplet size uniformity over conventional nozzles. The combination of these properties represents a tremendous opportunity to improve fuel delivery in engines. In addition to the performance benefits, this technology could be easily implemented into any direct-injected engine system, both compression ignition and spark ignition engines, reciprocating and rotary, because only the nozzle assembly needs to be developed for that particular fuel injector platform.


2018 ◽  
Vol 173 (2) ◽  
pp. 3-8
Author(s):  
Mirosław KARCZEWSKI ◽  
Krzysztof KOLIŃSKI

Majority of modern diesel engines is fitted with common-rail (CR) fuel systems. In these systems, the injectors are supplied with fuel under high pressure from the fuel rail (accumulator). Dynamic changes of pressure in the fuel rail are caused by the phenomena occurring during the fuel injection into the cylinders and the fuel supply to the fuel rail through the high-pressure fuel pump. Any change in this process results in a change in the course of pressure in the fuel rail, which, upon mathematical processing of the fuel pressure signal, allows identification of the malfunction of the pump and the injectors. The paper presents a methodology of diagnosing of CR fuel injection system components based on the analysis of dynamic pressure changes in the fuel rail. In the performed investigations, the authors utilized LabView software and a µDAC data acquisition module recording the fuel pressure in the rail, the fuel injector control current and the signal from the camshaft position sensor. For the analysis of the obtained results, ‘FFT’ and ‘STFT’ were developed in order to detect inoperative injectors based on the curves of pressure in the fuel rail. The performed validation tests have confirmed the possibility of identification of malfunctions in the CR system based on the pressure curves in the fuel rail. The ‘FFT’ method provides more information related to the system itself and accurately shows the structure of the signal, while the ’STFT’ method presents the signal in such a way as to clearly identify the occurrence of the fuel injection. The advantage of the above methods is the accessibility to diagnostic parameters and their non-invasive nature.


2014 ◽  
Vol 663 ◽  
pp. 426-430
Author(s):  
C.L. Hoo ◽  
Mohd Zaki Nuawi ◽  
S.M. Haris ◽  
S. Abdullah ◽  
Ahmad Rasdan Ismail

The Fuel injector is an important component in a vehicle engine for determining the performance of an engine. It is believed that, by knowing the current state of the injector, one can take any prior safety measure and ensuring the optimal performance of the engine. However, it is very difficult to study and analyse the fuel injection system in real time during the operation of the vehicle. A study was conducted in developing a method to monitor the fuel injector using the strain signal generated from the strain gauge sensors installed on the fuel injector. This method is practically implementable and can be used on the actual operation of the engine. A research rig was developed in order to visualise the behaviour of the injector at any instant by obtaining the three key parameters from the strain gage sensors which are the pulse width (ms), frequency (Hz) and pressure (bar). All data obtained from this experiment will be analysed using the Matlab software, where the I-kaz (Z∞) will be applied as the main method to clearly visualize the operation of the machine. The result shows that for the same pulse width and pressure, the series have the same pattern for I-kaz coefficient. They have a consistent trend compared to the Skewness and Kurtosis parameters. This method serves to predict and describe the behaviour of the fuel injector to ease the monitoring task at any instant throughout the engine operation.


Author(s):  
Jun-Kai Wang ◽  
Jing-Lun Li ◽  
Ming-Hsun Wu ◽  
Rong-Horng Chen

The effects of pulsed water injection at the intake port of a modern port fuel injection gasoline engine were investigated. A port water injection system was developed and the water injector was installed on the intake runner of the single cylinder motorcycle engine at a location upstream of the fuel injector. The results show that with a water-gasoline injection ratio of 1, more than 80% of NOx emission can be removed. The trade-off was a 25% reduction in torque output at 4000 rpm and 20% throttle opening; however, the decrease on torque can be controlled to be within 5% by reducing water-gasoline mass ratios to less than 0.6. We also performed NOx emission modeling using one-dimensional gas dynamics code with extended Zeldovich mechanism, and consistent results were found between numerical prediction and experimental measurements. The port water injection approach appears to be an effective means for reducing NOx emission from a gasoline engine at low speed and high load conditions without largely sacrificing the performances on torque output and unburned hydrocarbon emissions.


2005 ◽  
Author(s):  
Tatsuya Ujiie ◽  
Hidetoshi Saito ◽  
Minoru Ueda ◽  
Shunji Akamatsu ◽  
Akira Hayashi ◽  
...  

Author(s):  
Adel Mansour ◽  
Michael Benjamin ◽  
Erlendur Steinthorsson

The push towards higher specific fuel consumption and smaller, lighter packaging for aerospace gas turbine engines has resulted in large increases in engine operating pressure and temperature. This is a trend that is expected to continue, and as a result, thermal management of the hot engine section including the fuel nozzle, combustor, and turbine has emerged as a critical technology area requiring further development. For the fuel injection system, nozzle thermal management, turndown ratio, and atomization performance while maintaining correct combustor aerodynamics are the most important performance features that necessitate optimization. Significant advances in fuel injection concepts are required to meet the increasingly demanding combustor requirements. Complex heat-shielded designs are often required to reduce nozzle wetted-wall temperatures and prevent the formation of carbonaceous deposits within the fuel delivery passages. To support the development of advanced combustors and address these increasing performance demands, Parker has developed a new Hybrid Air Blast nozzle. Advanced analytical and experimental design tools were applied to reduce the cut-and-try approach previously used in nozzle development. The developed hybrid air blast design achieved excellent atomization performance over a wide range of fuel flow rates and air pressure drops. Thermal analysis of the nozzle showed that the wetted wall temperatures were reduced considerably when compared to previous designs operating at the same conditions. Eight-port circumferential spray patternation results were outstanding with the patternation factor at various values of liquid flow rate ranging between 0.12 and 0.18. This patternation factor is a significant improvement over those of current state-of-the-art injectors that are typically of the order of 0.25.


Author(s):  
Q Huang ◽  
D P Sansum

An experimental study of a fluidic type fuel injector for spark ignition (SI) engines is described in this paper. The fluidic injector unit consists of four monostable fluidic devices controlled by a solenoid interface and air–fuel mixing nozzles for better fuel atomization. The prototype fluidic injector unit was implemented on a research engine. The results of air–fuel ratio (AFR) variations, engine combustion characteristics and exhaust emissions from the fluidic injector were compared with those from a baseline solenoid type injector. It was demonstrated from single cylinder engine tests that the fluidic system produces 9 to 20 per cent lower hydrocarbon (HC) emissions and 5 to 8 per cent higher indicated mean effective pressure (IMEP) than the baseline injection system. This has confirmed the effectiveness of the use of air-assisted fluidic injectors and the fact that improved mixture preparation and better fuel presentation are obtained by the fluidic injector. However, the lean misfire limit by the fluidic injector is reduced by 1 AFR compared to that of the solenoid injector due to large AFR dispersions caused by cyclic fuel delivery variations of the fluidic device. It is envisaged that the fluidic injector potentially offers cost and emission benefits for SI engines when the cyclic flow stability is improved.


Author(s):  
Yong Yi ◽  
Aleksandra Egelja ◽  
Clement J. Sung

The development of a very high pressure diesel fuel injection system has been one of the key solutions to improve engine performance and to reduce emissions. The diesel fuel management in the injector directly affects how the fuel spray is delivered to the combustion chamber, and therefore affects the mixing, combustion and the pollutants formation. To design such a very high pressure diesel fuel injection system, an advanced CFD tool to predict the complex flow in the fuel injection system is required in the robust design process. In this paper, a novel 3D CFD dynamic mesh with cavitation model is developed to simulate the dynamic response of the needle motion of a diesel fuel injector corresponding to high common rail pressure and other dimensional design variables, coupling with the imbalance of the spring force and the flow force (pressure plus viscous force). A mixture model is used for cavitation resulting from high speed flow in fuel injector. Due to the lack of experimental data, the model presented in this paper is only validated by a limited set of experimental data. Required meshing strategy is also discussed in the paper.


Transport ◽  
2015 ◽  
Vol 31 (3) ◽  
pp. 305-311 ◽  
Author(s):  
Tomas Mickevičius ◽  
Stasys Slavinskas ◽  
Raimondas Kreivaitis

This paper presents a comparative experimental study for determining the effect of ethanol on functionality of a high pressure pump of the common rail fuel injection system. For experimental durability tests were prepared two identical fuel injection systems, which were mounted on a test bed for a fuel injection pump. One of the fuel injection systems was feed with diesel fuel; other fuel injection system was fuelled with ethanol–diesel fuel blend. A blend with 12% v/v ethanol and 88% v/v diesel fuel and low sulphur diesel fuel as a reference fuel were used in this study. To determine the effect of ethanol on the durability of the high pressure pump total fuel delivery performance and surface roughness of pump element were measured prior and after the test. Results show that the use of the ethanol–diesel blend tested produced a negative effect on the durability of the high pressure fuel pump. The wear of plungers and barrels when using ethanol–diesel fuel blend caused a decrease in fuel delivery up to 30% after 100 h of operation.


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