Thermal effects on the diesel injector performance through adiabatic 1D modelling. Part II: Model validation, results of the simulations and discussion

Payri, Raúl; Salvador, Francisco; Carreres, Marcos; Belmar-Gil, M.

doi:10.1016/j.fuel.2019.115663

Cited by 17 publications

(5 citation statements)

References 37 publications

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“…When the pilot quantity increased to 3 mg, stable conditions were reached but not with a fully developed flow, probably due to the sac pressure loss during the SOI process. 33,40,43–45 Sac pressure decreases mainly for two reasons: the volume of the displaced needle that is filled with fuel from its surroundings, plus the fuel that is injected into the chamber. Thus, even though the needle reached lift levels where it does not have any influence on the internal flow development, fully developed flow conditions are not reached until sac pressure recovers.…”

Section: Resultsmentioning

confidence: 99%

Measurements of the mass allocation for multiple injection strategies using the rate of injection and momentum flux signals

Payri

Gimeno

Martí-Aldaraví

et al. 2020

International Journal of Engine Research

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As legislations set very stringent environmental and fuel economy standards, researchers have pushed into a continuous development in all areas of the diesel engine. The recent evolution of the injection technologies has permitted to modify the fuel-delivery strategies. From what was a single pulse per injection event, modern systems allow to inject up to eight different times precisely per combustion cycle. In such sense, experimental results of the rate of injection and momentum flux could be useful for validation and improvement of computational models. Moreover, accurately quantifying the injected mass per pulse in a fuel–gas interface can provide data with more realistic engine-like conditions. To this end, this research presents measurements of the rate of injection and momentum flux for two simple multiple injection strategies: a pilot-main and a main-post. Boundary conditions included two rail and discharge pressures, two different pilot/post quantities and four dwell times. A new approach was employed to estimate the mass allocation with the momentum flux data, and results were compared to the rate of injection traces to verify the distribution calculated. On the results, signals for each pulse were successfully decoupled using its rising and falling edge. The shot-to-shot variability of the pilot/post injection was highly dependent on its transitory characteristics, and on the dwell time for post injections due to internal pressure waves. The injected mass per pulse was successfully measured as well in the momentum flux test rig, and the energizing time changed slightly to account for the different operation interfaces. Signals from both measurement campaigns showed a remarkable agreement when compared, ascertain the possibility of measuring the injected mass, and its allocation for multiple injection strategies, in the momentum flux test rig.

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Section: Resultsmentioning

confidence: 99%

Measurements of the mass allocation for multiple injection strategies using the rate of injection and momentum flux signals

Payri

Gimeno

Martí-Aldaraví

et al. 2020

International Journal of Engine Research

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“…After obtaining the fuel temperature in the nozzle hole, combined with the fuel pressure in the nozzle hole, the fuel density under the current temperature and pressure can be calculated according to the fuel density physical property formula. Then, the volume flow rate of fuel injected from the nozzle holes can be calculated by Equation (10):…”

Section: Influence Of Fuel Heating Effects On the Cycle Injection Qua...mentioning

confidence: 99%

“…This led to a change in the cavitation characteristics at the entrance of the injection hole, which significantly affected the injection quantity. Salvador et al [9] and Payri et al [10] used AMESim software to establish an adiabatic flow model for a CR injector and analyzed the variation in the fuel temperature increase at each orifice in the injector for different pre-main injection time intervals. They noted that the temperature increase in the fuel after flowing through an orifice was significantly affected by the initial fuel temperature and pressure difference.…”

Section: Introductionmentioning

confidence: 99%

Study on Dynamic Injection Prediction Model of High-Pressure Common Rail Injector under Thermal Effect

Liu¹,

Li²,

Wu³

et al. 2022

Energies

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This study investigates a prediction model for the cycle injection quantity in a high-pressure common rail injector under a transient thermal boundary. The results show that the transient temperature increase curve calculated by the mathematical model of the common rail injector under adiabatic flow is significantly different from the experimental data. A non-isothermal model of the injector coupled with heat transfer is established, which considers the actual heat transfer phenomenon. The excellent agreement between the new calculation results and the experimental data confirms that the fuel injection process of a common rail injector comprises the coupled phenomena of fuel heating and heat transfer. Based on the established simulation model, it is found that in the continuous injection process of the injector, owing to the thermal effect of injection, the cycle injection quantity decreases gradually with an increase in the injector working time and then stabilizes. Under the condition of an injection pulse width of 1.2 ms and frequency of 100 Hz, when the injection pressure increases from 140 MPa to 300 MPa, the reduction in the cycle injection quantity increases from 3.9% to 7.8%, because the higher injection pressure results in higher transient heat at the nozzle holes. In the work of common rail injector assemblies, to achieve more accurate control of the cycle injection quantity, it is necessary to include the correction of a decreasing cycle injection quantity caused by transient heat in the electronic control system.

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“…By introducing adiabatic flow assumption into the isothermal injector calculation model, the local fuel temperature variation along the flow direction in the injector was calculated. [18][19][20] Results showed significant changes in fuel temperature across some injector restrictions, and thermal effects also influenced the injection rate and duration. Bae et al 21 experimentally analyzed the influence of fuel temperature on the transient needle movement and fuel injection speed, and the researchers believed that the increase of fuel temperature would lead to a reduced injection duration and fuel injection speed.…”

Section: Introductionmentioning

confidence: 99%

Multi-objective optimization of fuel injection performance of a common rail injector

Fan

Lan

et al. 2023

International Journal of Engine Research

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The improvement of injector performance is important for the operation of common rail (CR) fuel systems. In this study, the optimization work has been carried out on a large-flow common rail injector. First, to simulate the injection process, a one-dimensional (1-D) model was developed and validated against the experimental data. The mathematical approximation model was also established to correlate the injection performance with the factors. Then, a multi-objective model by taking three design objectives into account was established and solved. Finally, Pareto front was obtained and the final optimization solution was determined. Furthermore, an extensive validation and analysis for the optimized results under various operating conditions was also carried out. Results shows that the three objectives, total response time, injection pressure fluctuation and injection pressure drop respectively, are improved by 11.75%, 39.12%, and 10.03% under the typical condition. And the proposed multi-objective optimization program based on design of experiment (DOE) technique, response surface methodology (RSM) and Elitist Non-dominated sorting genetic algorithm (NSGA-II) in present work can exhibit a good capability to optimize the problem of the injection performance in a CR fuel system.

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Thermal effects on the diesel injector performance through adiabatic 1D modelling. Part II: Model validation, results of the simulations and discussion

Cited by 17 publications

References 37 publications

Measurements of the mass allocation for multiple injection strategies using the rate of injection and momentum flux signals

Measurements of the mass allocation for multiple injection strategies using the rate of injection and momentum flux signals

Study on Dynamic Injection Prediction Model of High-Pressure Common Rail Injector under Thermal Effect

Multi-objective optimization of fuel injection performance of a common rail injector

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