scholarly journals Hydraulic Interactions between Injection Events Using Multiple Injection Strategies and a Solenoid Diesel Injector

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3087
Author(s):  
Simón Martínez-Martínez ◽  
Oscar A. de la Garza ◽  
Miguel García-Yera ◽  
Ricardo Martínez-Carrillo ◽  
Fausto A. Sánchez-Cruz
Keyword(s):  
Dwell Time ◽  
Injection Rate ◽  
Operating Conditions ◽  
Multiple Injection ◽  
Rail Pressure ◽  
Injection Strategy ◽  
Fuel Mass ◽  
And Control ◽  
Injection Strategies ◽  
Do So

An experimental study was performed to explore the influence of dwell time on the hydraulic interactions between injection events using pilot injection strategy, split injection strategy, post injection strategy and a solenoid diesel injector. To do so, a sweep of dwell time from 0.55 up to 2 ms using all multiple injection strategies and levels of rail pressure, of 80, 100 and 120 MPa, and single level of back pressure, of 5 MPa, was performed. The hydraulic interactions between injection events were characterized through the second injection hydraulic delay and second injection mass in an injection discharge curve indicator equipped with all the components required for its operation and control. In order to define the operating conditions of the multiple injection strategies, to ensure the same injected fuel mass in all cases, the characteristic curves of injection rate for the solenoid diesel injector studied were obtained. The second injection hydraulic delay increases with dwell time values in the range of 0.55–0.9 ms for all multiple injection strategies and levels of rail pressure tested. Conversely, the second injection hydraulic delay decreases with dwell time values higher than 0.9 ms. Moreover, the second hydraulic delay depends mainly on the dwell time and not on the injected fuel mass during the first injection event. The second injection mass increases with dwell values less than 0.6 ms. By contrast, the second injection mass is not significantly affected by that of the first injection at a dwell time higher than 0.6 ms.

Influence of fuel injection strategies on efficiency and particulate emissions of gasoline and ethanol blends in a turbocharged multi-cylinder direct injection engine

2019 ◽  
Vol 22 (1) ◽  
pp. 152-164 ◽  
Author(s):  
Ripudaman Singh ◽  
Taehoon Han ◽  
Mohammad Fatouraie ◽  
Andrew Mansfield ◽  
Margaret Wooldridge ◽  
...  
Keyword(s):  
Thermal Efficiency ◽  
Fuel Injection ◽  
Direct Injection ◽  
Injection Timing ◽  
Multiple Injection ◽  
Fuel Mass ◽  
Direct Injection Engine ◽  
Fuel Blends ◽  
Ethanol Blends ◽  
Injection Strategies

The effects of a broad range of fuel injection strategies on thermal efficiency and engine-out emissions (CO, total hydrocarbons, NOx and particulate number) were studied for gasoline and ethanol fuel blends. A state-of-the-art production multi-cylinder turbocharged gasoline direct injection engine equipped with piezoelectric injectors was used to study fuels and fueling strategies not previously considered in the literature. A large parametric space was considered including up to four fuel injection events with variable injection timing and variable fuel mass in each injection event. Fuel blends of E30 (30% by volume ethanol) and E85 (85% by volume ethanol) were compared with baseline E0 (reference grade gasoline). The engine was operated over a range of loads with intake manifold absolute pressure from 800 to 1200 mbar. A combined application of ethanol blends with a multiple injection strategy yielded considerable improvement in engine-out particulate and gaseous emissions while maintaining or slightly improving engine brake thermal efficiency. The weighted injection spread parameter defined in this study, combined with the weighted center of injection timing defined in the previous literature, was found well suited to characterize multiple injection strategies, including the effects of the number of injections, fuel mass in each injection and the dwell time between injections.

Effect of Injection Timing on PPCI and MPCI Mode Fueled With Straight-Run Naphtha

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Hongqiang Yang ◽  
Shijin Shuai ◽  
Zhi Wang ◽  
Jianxin Wang
Keyword(s):  
Diesel Fuel ◽  
Single Injection ◽  
Operating Conditions ◽  
Premixed Combustion ◽  
Spray Combustion ◽  
Injection Timing ◽  
Soot Emission ◽  
Compression Ignition ◽  
Injection Strategy ◽  
Injection Strategies

Partially premixed compression ignition (PPCI) and multiple premixed compression ignition (MPCI) mode of straight-run naphtha have been investigated under different injection strategies. The MPCI mode is realized by the multiple premixed combustion processes in a sequence of “spray-combustion-spray-combustion” around the compression top dead center. The spray and combustion events are preferred to be completely separated, without any overlap in the temporal sequence in order to ensure the multiple-stage premixed compression ignition. The PPCI mode is well known as the “spray-spray-combustion” sequence, with the start of combustion separated from the end of injection. Straight-run naphtha with a research octane number (RON) of 58.8 is tested in a single cylinder compression ignition engine whose compression ratio is 16.7 and displacement is 0.5 l. Double and triple injection strategies are investigated as the last injection timing sweeping at 1.0 MPa IMEP and 1800 rpm conditions. The MPCI mode is achieved using the double injection strategy, but its soot emission is higher than the PPCI mode under triple injection strategy. This is mainly because of the lower RON of the straight-run naphtha and the ignition delay is too short to form an ideally premixed combustion process after the second injection of straight-run naphtha. Diesel fuel is also tested under the same operating conditions, except for employing a single injection strategy. The naphtha PPCI and MPCI mode both have lower fuel consumption and soot emission than diesel fuel single injection mode, but the THC emissions are both higher than that of diesel fuel.

scholarly journals DEVELOPING AND VALIDATING A GT-SUITE BASED MODEL FOR A SECOND GENERATION COMMONRAIL SOLENOID INJECTOR

2021 ◽  
Vol 59 (3) ◽  
pp. 390
Author(s):  
Dat Xuan Nguyen ◽  
Vu Hoang Nguyen ◽  
Phuong Xuan Pham
Keyword(s):  
Second Generation ◽  
Injection Rate ◽  
Operating Conditions ◽  
Calibration Data ◽  
Rail Pressure ◽  
Start Of Injection ◽  
Wide Range ◽  
Experiment And Simulation ◽  
The Difference ◽  
Physical And Chemical

Injection profiles, containing important parameters like injection rate, directly affect the spray structure, fuel-air mixture quality, and as such the physical and chemical processes occurring in the IC engine’s combustion chamber. Therefore, injection profiles are one of the keys to improving power, thermal efficiency and minimizing the emission for IC engines. In this paper, a GT-Suite - based simulation model for a second generation solenoid commonrail injector typically utilized in Hyundai 2.5 TCI-A diesel engines, has been successfully developed and validated. The validation is done by using experimental data are acquired by a Zeuch’s method-based Injection Analyzer (UniPg STS) in University of Perugia, Italy. The calibration data is measured over a wide range of rail pressure and energizing time (ET) corresponding to the engine operating conditions. The results show that the injector model developed here is reliable and suitable for examining the injector’s hydraulic characteristics. The difference in start of injection values obtained through experiment and simulation is only about 15 µs. The total injection volumes obtained through experiment and simulation under ET > 0.8 ms is less than     10 % while the difference is quite high under ET < 0.8 ms and high rail pressure (up to 34.5 %).

Influence of injection strategies on knock resistance and combustion characteristics in a DISI engine

2018 ◽  
Vol 233 (10) ◽  
pp. 2637-2649
Author(s):  
Haiqiao Wei ◽  
Jie Yu ◽  
Aifang Shao ◽  
Lei Zhou ◽  
Jianxiong Hua ◽  
...  
Keyword(s):  
Single Injection ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Combustion Stability ◽  
Injection Timing ◽  
Split Injection ◽  
Injection Strategy ◽  
Double Injection ◽  
The Impact ◽  
Injection Strategies

The combustion of a direct injection spark ignition engine is significantly affected by the fuel injection strategy due to the impact this strategy has on the gas-mixture formation and the turbulence flow. However, comprehensive assessments on both knock and engine performances for different injection strategies are generally lacking. Therefore, the main objective of the present study is to provide an experimental evidence of how a single injection strategy and a split injection strategy compare in terms of both knock tendency and engine performances like thermal efficiency, torque and combustion stability. Starting from the optimization of a single injection strategy, a split injection strategy is then evaluated. Under the present operating conditions, an optimum secondary injection timing of 100 CAD BTDC is found to have significant improvements on both the knock resistance and the overall engine performances. It should be noted that the present results indicate that the relationship between double injection and anti-knock performance is not monotonous. In addition, the double injection shows superior potential in improving fuel economy and power performance in contrast with the single injection thanks to a more stable combustion when a late injection timing is applied.

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

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4221
Author(s):  
Intarat Naruemon ◽  
Long Liu ◽  
Qihao Mei ◽  
Xiuzhen Ma
Keyword(s):  
Diesel Engines ◽  
Injection Rate ◽  
Pollutant Emission ◽  
Gas Jet ◽  
Entrainment Rate ◽  
Multiple Injection ◽  
Mixing Process ◽  
Injection Strategy ◽  
One Dimensional ◽  
Injection Duration

Common rail systems have been widely used in diesel engines due to the stricter emission regulations. The advances in injector technology and ultrahigh injection pressure greatly promote the development of multiple-injection strategy, leading to the shorter injection duration and more variable injection rate shape, which makes the mixing process more significant for the formation of pollutant emission. In order to study the mixing process of diesel sprays under variable injection rate shapes and find the optimized injection strategy, a one-dimensional spray model was modified in this paper. The model was validated by the measured spray penetrations based on shadowgraphy experiments with the varying injection rate. The simulations were performed with five injection rate shapes, triangle, ramping-up, ramping-down, rectangle and trapezoid. Their spray penetrations, entrainment rates and equivalence ratios along spray axial distance are compared. The potentials of multiple-injection and gas-jet after end-of-injection (EOI) to improve mixing process and emission reduction are discussed finally. The results indicated that ramping-up injection rate obtains the highest entrainment rate after EOI, and it needs 1.5 times of injection duration for the entrainment wave to arrive at the spray tip. For the other four injection rates, the sprays can be treated as a steady-like state, needing twice of injection duration from EOI to the time the entrainment wave reaches the spray tip. The multiple-injection with proper injection rate shape enhanced the entrainment rate, and the gas-jet after EOI affected the mixture distribution and entrainment rate in spray tail under ramping-down injection rate.

Numerical-Experimental Study and Solutions to Reduce the Dwell Time Threshold for Fusion-Free Consecutive Injections in a Multijet Solenoid-Type C.R. System

2006 ◽  
Author(s):  
Andrea Emilio Catania ◽  
Alessandro Ferrari ◽  
Ezio Spessa
Keyword(s):  
Dwell Time ◽  
Operating Conditions ◽  
Injection System ◽  
Numerical Code ◽  
Needle Valve ◽  
Time Range ◽  
Time Interval ◽  
Particulate Emissions ◽  
And Control ◽  
Nozzle Opening

In ‘Multijet’ Common Rail (C.R.) diesel injection systems, when two consecutive injection current-pulses are approached to each other, the fusion of the two injections can occur. This causes undesired excessive amount of injected fuel, which leads to worsening of particulate emissions and fuel consumption. In order to avoid such a phenomenon, lower limits to the values of dwell time are introduced in the control unit maps, by means of a conservatively overestimated threshold, limiting the flexible management of multiple injections and C.R. system capability to perform a larger number of injection shots. The reason of the injection fusion is mainly due to the time delay between the electrical signal to the solenoid and the needle lift at both valve opening and closure. In particular, the dwell-time range inside of which injection fusion occurs was shown to decrease by reducing the nozzle closure delay. Experimental tests were carried out on a high-performance Moehwald-Bosch MEP2000/CA4000 test bench for determining the functional dependence of nozzle closure and opening delays on solenoid energizing time and nominal rail pressure. Besides, a mathematical relation between the solenoid energizing time and the injection time interval was determined. A Multijet C.R. injection system mathematical model, that was previously developed, including thermodynamics of liquids, fluid dynamics, subsystem mechanics, and electromagnetism equations, was applied to better understand the cause and effect relationships for nozzle opening and closure delays. In particular, numerical results on the time histories of delivery- and control-chamber pressures, pilot- and needle-valve lifts, mass flow rates through Z and A holes, were obtained and analyzed in order to highlight the dependence of nozzle opening and closure delays on electro-injector internal geometric features and on the needle dynamics. For all the considered operating conditions, the model predictions were compared to the experimental injection flow-rate patterns and to the pressure data taken at the injector inlet, for assessment. The nozzle closure delay was shown to strongly depend on the needle dynamics. Parametric tests were carried out with the numerical code by changing needle and control plunger mass, needle spring preload and stiffness, maximum needle stroke, in order to identify configurations useful for minimizing the nozzle closure delay. On the basis of the indications derived from these numerical tests, a modified version of the commercial electro-injector was realized so as to achieve effectively reduced nozzle closure delays and very close sequential injections without any fusion between them.

scholarly journals Experimental Evaluation of an Internally Passively Pressurized Circulation Control Propeller

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Jonathan Kweder ◽  
Cale H. Zeune ◽  
Jon Geiger ◽  
Andrew D. Lowery ◽  
James E. Smith
Keyword(s):  
Stagnation Pressure ◽  
Operating Conditions ◽  
Circulation Control ◽  
Trailing Edge ◽  
Lifting Force ◽  
Percent Increase ◽  
Propeller Blades ◽  
Almost All ◽  
And Control ◽  
Do So

The purpose of circulation control for fixed wing aircrafts is to increase the lifting force when large lifting forces and/or slow speeds are required, such as at takeoff and landing. Wing flaps and slats are used on almost all fixed-wing aircraft. While effective in increasing lift, they do so with penalty of increasing drag, weight, and control complexity. The goal of this research was to find an alternative way of pumping pressurized air to the trailing edge slot on a UAV propeller. This design called for rerouting stagnation pressure from the frontal propeller area through the inside of the propeller blades to ejection slots on the trailing edge. This allows for the forward velocity of the aircraft to drive the pressurization of the circulation control plenum passively, without additional hardware. For this study, a Clark-Y airfoil section propeller with an overall diameter of 0.609 meters was designed and tested. The comparison of the augmented to unaugmented propeller showed a 5.12 percent increase in efficiency, which is shown to act over the entire range of flight envelopes of the aircraft and is shown to be particularly beneficial at advance ratios above 0.30, normal operating conditions of propeller-driven UAVs.

scholarly journals One-dimensional modeling of the interaction between close-coupled injection events for a ballistic solenoid injector

2018 ◽  
Vol 20 (4) ◽  
pp. 452-469 ◽  
Author(s):  
Raul Payri ◽  
Joaquin De la Morena ◽  
Vincenzo Pagano ◽  
Ali Hussain ◽  
Gilbert Sammut ◽  
...  
Keyword(s):  
Dwell Time ◽  
Dynamic Pressure ◽  
Injection Pressure ◽  
Operating Conditions ◽  
One Dimensional ◽  
Dimensional Modeling ◽  
Custom Made ◽  
Wide Range ◽  
Common Rail Injector ◽  
Injection Strategies

In this article, an investigation of a solenoid common-rail injector has been carried out to understand the hydraulic interactions between close-coupled injection events. For this purpose, a one-dimensional model of the injector was developed on GT-SUITE software. The geometrical and hydraulic characteristics of the internal elements of the injector, needed to construct the model, were obtained by means of different custom-made experimental tools. The dynamic behavior of the injector was characterized using an EVI rate of injection meter. The hydraulic results from the model show a good alignment with the experiments for single injections and a varied degree of success for multiple injections. Once the model was validated, it has been used to understand the injector performance under multiple-injection strategies. The mass of a second injection has shown to highly depend on the electrical dwell time, especially at low values, mostly due to the dynamic pressure behavior in the needle seat. The critical dwell time, defined as the minimum electrical dwell time needed to obtain two independent injection events, has been numerically obtained on a wide range of operating conditions and correlated to injection pressure and energizing time of the first injection. Finally, the increase in the needle opening velocity of the second injection compared to the single-injection case has been analyzed for close-coupled injection events.

scholarly journals Temporal Evolution of Split-Injected Fuel Spray at Elevated Chamber Pressures

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4284 ◽  
Author(s):  
Gang Wu ◽  
Xinyi Zhou ◽  
Tie Li
Keyword(s):  
High Speed ◽  
Fuel Injection ◽  
Penetration Rate ◽  
Injection Pressure ◽  
Test System ◽  
Injection Rate ◽  
Spray Angle ◽  
Split Injection ◽  
Injection Strategy ◽  
Injection Strategies

For reducing soot and NOx emissions, an effective method is to apply split injection strategies. In this research, characteristics of split injection were investigated by applying the pilot-main injection strategy and main-post injection strategy. The injection mass of fuel with the two strategies was measured by an in-house fuel injection rate test system based on the Bosch method. The development of spray tip and tail penetrations, as well as the evolvement of the spray angle when applying these two injection strategies, were explored by employing the high speed shadowgraphy at various injection pressures and surrounding gas densities. The results indicate the tail penetration rate of spray has no relation to the fuel injection pressure. However, the increased injection pressure causes a faster penetration development in the spray tip position. It was also found that the spray tip penetration rate of the second spray is slightly slower than that of the first spray at the beginning stage of injection, but it was significantly larger than the first one at the later stage.

Investigation of fuel injection rate identification algorithm based on rail pressure fluctuation characteristics induced by injection

2021 ◽  
pp. 095440702110393
Author(s):  
Xuejian Ma ◽  
Yan Lei ◽  
Tao Qiu ◽  
Jingen Wang ◽  
Guangzhao Yue
Keyword(s):  
Pressure Sensor ◽  
Pressure Fluctuation ◽  
Control Algorithm ◽  
Fuel Injection ◽  
Injection Rate ◽  
Operating Conditions ◽  
Fuel System ◽  
Rail Pressure ◽  
Fuel Injection Rate ◽  
Injection Pulse

As an important part of the common-rail (CR) fuel system for diesel engines, the injector circulation capacity and the fuel injection mass flow rate vary with carbon deposition and wear, affecting the engine output performance. This study proposes a method to identify the fuel injection rate online, based on the rail pressure fluctuation characteristics induced by fuel injection. The control algorithm uses the signal from the existing rail pressure sensor; the diesel engine does not require modification or additional sensors. A quasi-dimensional model of the CR fuel system was built to analyse the rail pressure wave fluctuation characteristics, and a parameter K was defined as the pressure drop rate. Based on K, a control algorithm was proposed. A high-pressure fuel pump test rig was built to test the fuel injection performance under different operating conditions, and the experimental data were processed by wavelet transform. From the test data, the K of the CR system was analysed using the feedback of the rail pressure sensor. The experimental results show that the value of K increases with an increase in the initial pressure and injection pulse, and is independent of the injection mode. The algorithm is feasible, and works more accurately with a longer injection pulse and a lower pump speed. This method uses the existing rail pressure sensor, does not incur extra cost and has great potential for improving the injection accuracy.

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