Possibilities of Wall Heat Transfer Measurements at a Supercharged Euro VI Heavy-Duty Diesel Engine with High EGR-Rates, an In-Cylinder Peak Pressure of 250 Bar and an Injection Pressure up to 2500 Bar

2019 ◽  
Author(s):  
Christian Hennes ◽  
Jürgen Lehmann ◽  
Thomas Koch
Keyword(s):  
Heat Transfer ◽  
Diesel Engine ◽  
Peak Pressure ◽  
Injection Pressure ◽  
Wall Heat Transfer ◽  
Heavy Duty ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel

Effect of Altitude on In-Cylinder Heat Transfer of a Heavy Duty Diesel Engine

2021 ◽  
Author(s):  
Zhentao Liu ◽  
Jinlong Liu
Keyword(s):  
Heat Transfer ◽  
Diesel Engine ◽  
High Altitude ◽  
Heat Loss ◽  
The United States ◽  
Bulk Temperature ◽  
Atmospheric Conditions ◽  
Heavy Duty ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel

Abstract Diesel engines are the predominant power source in trucking industry. Heavy duty trucks move more than 70% of all goods transported around the United States. The atmospheric conditions vary with altitude but are vital to diesel engine performance, efficiency, and emissions. Existing studies reported reduced thermal efficiency and increased emissions when truck engines were operated at high altitude. As the heat loss is a key parameter related to engine efficiency, the goal of this paper was to investigate the altitude impacts on in-cylinder heat transfer characteristics. A single cylinder four-stroke heavy duty diesel engine was performed at constant speed and load but different intake pressure to simulate the varying atmospheric conditions at different altitude. The engine raised the amount of diesel mass injected to the cylinder per cycle to maintain the identical power output under decreased atmospheric pressure and to compensate the combustion deterioration happened inside the cylinder. The experimental results indicated a higher bulk temperature at high altitude due to a smaller amount of mixture mass trapped inside the cylinder. Such a larger temperature difference between the hot products and the cold walls increased in-cylinder heat transfer to the coolant, especially during the combustion period. Specifically, a rise in 2000m altitude resulted in up to ∼2% increment in heat loss to the atmosphere per fired cycle. As a result, applying thermal coating to improve fuel economy is more necessary in high altitude states, such as Colorado and Wyoming.

A Fast Coupled CFD-Thermal Analysis of a Heavy Duty Diesel Engine Water Cooling System

2008 ◽  
Author(s):  
Mazdak Jafarabadi ◽  
Hamidreza Chamani ◽  
Amir Malakizadi ◽  
Seyed Ali Jazayeri
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Heat Flux ◽  
Diesel Engine ◽  
Cooling System ◽  
Nucleate Boiling ◽  
Heavy Duty ◽  
Engine Cooling ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel

In recent years, the design of an efficient cooling system together with good thermal efficiency for a new engine is becoming a critical task and therefore the need for an accurate and fast thermo-fluid simulation of engine cooling system is of vital importance. In this study, a detailed CFD and thermal FE simulation of a 12 cylinders V-type medium speed heavy duty diesel engine cooling system has been carried out using ANSYS-CFX commercial code. At first, a global model, for one bank with six cylinders, has been simulated using appropriate mesh density which ensures the accuracy of the results together with reasonable computational time. At this stage, the worst cylinder has been selected based on the wall temperature and the cooling flow rate. Later, using the inlet and outlet boundary conditions extracted from the global model, a series of detailed thermo-fluid analyses have been conducted for the worst cylinder with a finer mesh. The subcooled nucleate boiling heat transfer computation is carried out using the boiling departure lift-off (BDL) model, in which the total heat flux is assumed to be additively composed of a forced convective and a nucleate boiling component. In order to obtain the temperature field for components under consideration, a comprehensive thermal analysis has been preformed coupling with the detailed CFD analyses to reach an accepted value through transferring data between the CFD and FEA software. This method leads to an accurate prediction of the wall temperature and heat flux. It is observed that at hot spots, nucleate boiling occurs for low coolant flow regions specifically around the cylinder head’s exhaust port and liner coolant side wall. Also a considerable increment in the Heat Transfer Coefficient (HTC) has been observed on the superheated regions where the boiling is initiated.

Multi-Dimensional Simulation on the Matching of Combustion Chamber and Injection Pressure for a Heavy-Duty Diesel Engine

2012 ◽  
Vol 516-517 ◽  
pp. 623-627
Author(s):  
Ye Yuan ◽  
Guo Xiu Li ◽  
Yu Song Yu ◽  
Peng Zhao ◽  
Hong Meng Li
Keyword(s):  
Diesel Engine ◽  
Combustion Chamber ◽  
Injection Pressure ◽  
Power Stroke ◽  
Heavy Duty ◽  
Power Performance ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel ◽  
Dimensional Simulation ◽  
Dilute Mixture

Multi-dimensional simulation was applied for the investigation of the combustion system of a heavy-duty diesel engine. Firstly, the matching of combustion chamber and injection pressure has been determined by simulation. Then through intermediate characteristic parameters which could quantitatively describe the properties of the mixing and combustion, the influence of the matching of chamber caliber ratios and injection pressure on each sub-process in compression and power stroke was analyzed comprehensively. The results showed that, for the model studied in this article, increasing the combustion chamber caliber ratio and injection pressure could help expanding the distribution range of the mixture in cylinder, making the mixture more uniform, increasing the proportion of the dilute mixture, thus effectively improved the power performance.

Modeling the Fuel Spray of a High Reactivity Gasoline Under Heavy-Duty Diesel Engine Conditions

2017 ◽  
Author(s):  
Yuanjiang Pei ◽  
Roberto Torelli ◽  
Tom Tzanetakis ◽  
Yu Zhang ◽  
Michael Traver ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Ambient Pressure ◽  
Injection Pressure ◽  
High Reactivity ◽  
Operating Conditions ◽  
Heavy Duty ◽  
Fuel Temperature ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel

Recent experimental studies on a production heavy-duty diesel engine have shown that gasoline compression ignition (GCI) can operate in both conventional mixing-controlled and low-temperature combustion modes with similar efficiency and lower soot emissions compared to diesel at a given engine-out NOx level. This is primarily due to the high volatility and low aromatic content of high reactivity, light-end fuels. In order to fully realize the potential of GCI in heavy-duty applications, accurate characterization of gasoline sprays for high-pressure fuel injection systems is needed to develop quantitative, three-dimensional computational fluid models that support simulation-led design efforts. In this work, the non-reacting fuel spray of a high reactivity gasoline (research octane number of ∼60, cetane number of ∼34) was modeled under typical heavy-duty diesel engine operating conditions, i.e., high temperature and pressure, in a constant-volume combustion chamber. The modeling results were compared to those of a diesel spray at the same conditions in order to understand their different behaviors due to fuel effects. The model was developed using a Lagrangian-Particle, Eulerian-Fluid approach. Predictions were validated against available experimental data generated at Michigan Technological University for a single-hole injector, and showed very good agreement across a wide range of operating conditions, including ambient pressure (3–10 MPa), temperature (800–1200 K), fuel injection pressure (100–250 MPa), and fuel temperature (327–408 K). Compared to a typical diesel spray, the gasoline spray evaporates much faster, exhibiting a much shorter liquid length and wider dispersion angle which promote gas entrainment and enhance air utilization. For gasoline, the liquid length is not sensitive to different ambient temperatures above 800 K, suggesting that the spray may have reached a “saturated” state where the transfer of energy from the hot gas to liquid has already been maximized. It was found that higher injection pressure is more effective at promoting the evaporation process for diesel than it is for gasoline. In addition, higher ambient pressure leads to a more compact spray and fuel temperature variation only has a minimal effect for both fuels.

An Evaluation of Combustion and Emissions Performance With Low Cetane Naphtha Fuels in a Multi-Cylinder Heavy-Duty Diesel Engine

2015 ◽  
Author(s):  
Yu Zhang ◽  
Alexander Voice ◽  
Tom Tzanetakis ◽  
Michael Traver ◽  
David Cleary
Keyword(s):  
High Temperature ◽  
Diesel Engine ◽  
Low Temperature ◽  
Compression Ratio ◽  
Fuel Injection ◽  
Fuel Efficiency ◽  
Injection Pressure ◽  
Heavy Duty ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel

Future projections in global transportation fuel use show a demand shift towards diesel and away from gasoline. At the same time greenhouse gas regulations will drive higher vehicle fuel efficiency and lower well-to-wheel CO2 production. Naphtha, a contributor to the gasoline stream and requiring less processing at the refinery level, is an attractive candidate to mitigate this demand shift while lowering the overall greenhouse gas impact. In this work, low cetane and high volatility gasoline-like fuels have shown potential to achieve high fuel efficiency with low engine-out emissions in a production commercial vehicle engine. This study investigates the combustion and emissions performance of two low cetane naphtha fuels (Naphtha 1: RON59; Naphtha 2: RON69) and one ultra-low sulfur diesel (ULSD) in a model year (MY) 2013, six-cylinder, heavy-duty diesel engine. The engine is equipped with a single-stage variable geometry turbocharger (VGT) and a fuel injection system that is capable of 2500 bar fuel injection pressure. The engine has a stock geometric compression ratio of 18.9. To date, most studies in this area have been conducted using single-cylinder research engines. Aramco aims to better understand the implications on hardware and software design in a multi-cylinder engine with a production engine air system. Engine testing was focused on the Heavy-Duty Supplemental Emissions Test (SET) “B” speed over a load sweep from 5 to 15 bar BMEP. At each operating point, NOx sweeps were conducted over wide ranges (e.g., 0.2 → 3 g/hp-hr) to understand the implications of fuel reactivity as well as other properties on combustion behavior under both high temperature mixing-controlled combustion and low temperature premixed combustion. At 10–15 bar BMEP, mixing-controlled combustion dominates the engine combustion process. Under a compression ratio of 18.9, cylinder pressure and temperature are sufficiently high to suppress the reactivity (cetane number) difference between ULSD and the low cetane naphtha fuels. As a result, the three test fuels showed similar ignition delay under high temperature and pressure conditions. Nevertheless, naphtha fuels still exhibited notable soot reduction compared to ULSD. Under mixing-controlled combustion, this is likely due to their lower aromatic content and higher volatility. At 10 bar BMEP, Naphtha 1 generated less soot than Naphtha 2 since it contains less aromatics and is more volatile. When operated at light load, in a less reactive thermal environment, the lower reactivity naphtha fuels led to longer ignition delays than ULSD. As a result, the soot benefit of naphtha fuels was enhanced. Overall, naphtha fuels and ULSD had similar fuel efficiency. Utilizing the soot benefit of the naphtha fuels, engine-out NOx was calibrated from the production level of 3–4 g/hp-hr down to 2–2.5 g/hp-hr over the twelve non-idle SET steady-state modes. At this reduced NOx level, naphtha fuels were still able to maintain a soot advantage over ULSD and remain “soot-free” (smoke ≤ 0.2 FSN) while achieving diesel-equivalent fuel efficiency. Finally, partially premixed compression ignition (PPCI) low temperature combustion (LTC) operation (NOx ≤ 0.2 g/hp-hr; smoke ≤ 0.2 FSN) was achieved with both of the naphtha fuels at 5 bar BMEP through a late injection approach with high injection pressure. Under high EGR dilution, Naphtha 2 showed an appreciably longer ignition delay than Naphtha 1, resulting in a soot reduction benefit. Early injection PPCI operation cannot be attained with the stock engine compression ratio due to excessive pressure rise rates. Although the late injection PPCI operation offered a significant NOx benefit over mixing-controlled combustion operation, it led to lower fuel efficiency with undesirably late combustion phasing. This points the research towards a lower engine compression ratio and an air system upgrade to promote high efficiency PPCI LTC operation.

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