CFD Analysis of VVT/VVA on the Gas Exchange and Fuel-Air Mixing in a Diesel Engine

Atomization and fuel-air mixing is an important process in diesel combustion. It directly affects the combustion and emission of diesel engine. Optical technique has the advantage of being unobtrusive in nature when compared to other technique. nanospark unit that has spark duration of 30ns was used as a lightsource to capture high resolution spray image using still film camera. The very short duration of the spark freeze the fast movement of the spray droplet, and sharp image of fuel droplet to be successfully captured by the camera, and then analyzed for sizing and spatial distribution. In addition, by using a more elaborate optical setup, dual image of the same spray can be captured, with a very short time interval between each of them. This provides the means to study dynamic behaviors of the diesel spray and also the droplets, as the progression of the spray and trajectory and velocity of the droplet can be analyze from these images. With the proposed optical technique and optical arrangement, microscopic detail of the diesel engine spray can be captured. Critical data such as droplet sizing can be extracted from this high resolution image. Furthermore, by introducing a more sophisticated optical arrangement coined dual-nano spark photography method, the droplet dynamic behaviors such as flying angle and velocity can be study.

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Modeling the Gas Exchange Processes of a Modern Diesel Engine With an Integrated Physics-Based and Data-Driven Approach

Volume 2: Modeling and Control of Engine and Aftertreatment Systems; Modeling and Control of IC Engines and Aftertreatment Systems; Modeling and Validation; Motion Planning and Tracking Control; Multi-Agent and Networked Systems; Renewable and Smart Energy Systems; Thermal Energy Systems; Uncertain Systems and Robustness; Unmanned Ground and Aerial Vehicles; Vehicle Dynamics and Stability; Vibrations: Modeling, Analysis, and Control ◽

10.1115/dscc2019-9226 ◽

2019 ◽

Author(s):

Jorge Pulpeiro Gonzalez ◽

King Ankobea-Ansah ◽

Elena Escuder Milian ◽

Carrie M. Hall

Keyword(s):

Diesel Engine ◽

Gas Exchange ◽

High Efficiency ◽

Direct Injection ◽

Data Driven ◽

Model Framework ◽

Variable Valve Actuation ◽

Exchange Processes ◽

Data Driven Approach ◽

Using Data

Abstract The gas exchange processes of engines are becoming increasingly complex since modern engines leverage technologies including variable valve actuation, turbochargers, and exhaust gas recirculation. Control of these many devices and the underlying gas flows is essential for high efficiency engine concepts. If these processes are to be controlled and estimated using model-based techniques, accurate models are required. This work explores a model framework that leverages a data-driven model of the turbocharger along with submodels of the intercooler, intake and exhaust manifolds and engine processes to provide cylinder-specific predictions of the pressure and temperatures of the gases across the system. This model is developed and validated using data from a 2.0 liter VW turbocharged, direct-injection diesel engine and shown to provide accurate prediction of critical gas properties.

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Scaling liquid penetration in evaporating sprays for different size diesel engines

International Journal of Engine Research ◽

10.1177/1468087419889835 ◽

2019 ◽

Vol 21 (9) ◽

pp. 1662-1677 ◽

Cited By ~ 3

Author(s):

Xinyi Zhou ◽

Tie Li ◽

Yijie Wei ◽

Ning Wang

Keyword(s):

Diesel Engine ◽

Diesel Engines ◽

High Speed ◽

Scaling Laws ◽

Fuel Injection ◽

Pollutant Emissions ◽

Liquid Penetration ◽

Spray Characteristics ◽

Penetration Length ◽

Air Mixing

Scaled model experiments can greatly reduce the cost, time and energy consumption in diesel engine development, and the similarity of spray characteristics has a primary effect on the overall scaling results of engine performance and pollutant emissions. However, although so far the similarity of spray characteristics under the non-evaporating condition has been studied to some extent, researches on scaling the evaporating sprays are still absent. The maximum liquid penetration length has a close relationship with the spray evaporation processes and is a key parameter in the design of diesel engine spray combustion system. In this article, the similarity of maximum liquid penetration length is theoretically derived based on the hypotheses that the spray evaporation processes in modern high-pressure common rail diesel engines are fuel–air mixing controlled and local interphase transport controlled, respectively. After verifying that the fuel injection rates are perfectly scaled, the similarity of maximum liquid penetration length in evaporating sprays is studied for three scaling laws using two nozzles with hole diameter of 0.11 and 0.14 mm through the high-speed diffused back-illumination method. Under the test conditions of different fuel injection pressures, ambient temperatures and densities, the lift-off law and speed law lead to a slightly increased maximum liquid penetration length, while the pressure law can well scale the maximum liquid penetration length. The experimental results are consistent with the theoretical analyses based on the hypothesis that the spray evaporation processes are fuel–air mixing controlled, indicating that the local interphase transports of energy, momentum and mass on droplet surface are not rate-controlled steps with respect to spray evaporation processes.

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Electro Hydraulic Gas Exchange Valve Actuation of 4-Stroke Large Bore Diesel Engine

8th FPNI Ph.D Symposium on Fluid Power ◽

10.1115/fpni2014-7804 ◽

2014 ◽

Author(s):

Mika Herranen ◽

Kalevi Huhtala

Keyword(s):

Diesel Engine ◽

Gas Exchange ◽

Power Consumption ◽

Controller Design ◽

Control Valve ◽

Hydraulic Actuator ◽

Direction Control ◽

Test Engine ◽

Return Spring ◽

Valve Actuation

After several years of study, a large bore diesel engine Electro-Hydraulic Valve Actuation (EHVA) system has reached a development point where the system has been successfully used for years in laboratory test engine environment too. During the evolution of the EHVA, insight of the hydraulic and control systems features has been cleared. This paper concludes main findings and results of EHVA research in Tampere University of Technology / IHA. The hydraulic circuit effect to the power consumption of EHVA is clear. 3-way controlled actuator has advantages compared to 4-way controlled system. Direction control valve defines controllability of the system, and has source of the largest single component power loss. Hydraulic actuator design has also a fair effect to the overall power consumption when pressure force vs. required flow changes heavily, due to load forces. Mechanically, return spring design of the gas exchange valve has great effect to power consumption too. Controller design is dependent on what kind of performance is required. The controller compensates lack of control valve bandwidth, and reacts to changing environmental variables. In this state, the Iterative Learning Controller (ILC) has proved the best choice. If gas exchange valve exact lift motion during the lift event is not important but variation between the strokes is kept in narrow range, a Model-Based Controller (MBC) is a strong option.

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