Analysis of a Prechamber Ignited HPDI Gas Combustion Concept

Zelenka, Ján; Kammel, Gernot; Wimmer, Andreas; Bärow, Enrico; Huschenbett, Matthias

doi:10.4271/2020-01-0824

Cited by 18 publications

(7 citation statements)

References 10 publications

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“…Kammel et al initially developed this system using CFD modeling and the simulations showed that the pre-chamber ignited single-fuel HPDI concept resulted in mixing controlled combustion of natural gas that yield diesel-like engine performance. A followon study by Zelenka et al (Zelenka et al, 2020) experimentally demonstrated this prechamber ignited HPDI natural gas combustion concept on a large 6 L single-cylinder research engine. They were able to show experimentally that the concept delivers diesel engine combustion characteristics, such as high thermal efficiency and precise control over the start of combustion and the rate of combustion energy release.…”

Section: Mixing Controlled Combustion With High Octane Fuels Enabled mentioning

confidence: 93%

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A System to Enable Mixing Controlled Combustion With High Octane Fuels Using a Prechamber and High-Pressure Direct Injector

2021

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The demand for transportation energy is growing and thus improving the efficiency and reducing the pollutant emissions from this energy sector is critical. Transportation has historically been powered by the internal combustion engine (ICE). Many alternative technologies are being evaluated to replace the ICE, such as hydrogen fuel cells and battery electrics. These technologies appear attractive at the vehicle-level but have many challenges regarding life cycle emissions and lack of infrastructure. A more pragmatic approach would be to use the current liquid fuels infrastructure with cleaner burning, renewable fuels that have the potential to be carbon neutral, such as low carbon alcohols (e.g., methanol, ethanol, propanol, and butanol). These alternative fuels tend to have a high-octane number, making them great candidates for conventional spark ignition (SI) engines. However, SI engines are plagued by several challenges when it comes to high load operation, such as pre-ignition, knock-limited peak torque, poor snap torque response, high levels of cyclic variability, and sensitivity to varying fuel properties. The objective of this research is to develop a technology that will allow high octane fuels to be utilized in engines and utilize robust mixing controlled combustion. The proposed technology is a system which utilizes an active prechamber in the shape of an annulus and a high-pressure direct fuel injector. The active prechamber and the high-pressure direct injector use the same liquid fuel, which could be any fuel that has relatively high volatility and high resistance to autoignition (i.e., high-octane number). The active prechamber is fired late in the compression stroke and hot jet flames are ejected from the prechamber. These jets ignite the direct injected fuel sprays near top dead center, establishing a mixing controlled combustion event. This will allow for robust operation across the full engine operating space with clean burning renewable fuels, without the shortcomings of SI engines regarding knock-limited operation and part load efficiency.

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Section: Mixing Controlled Combustion With High Octane Fuels Enabled mentioning

confidence: 93%

“…Even with recent technological advancements, direct injected LNG systems typically operate with a peak injection pressure of 500-600 bar (McTaggart-Cowan et al, 2015;Mumford et al, 2017;Zelenka et al, 2020).…”

Section: Mixing Controlled Combustion With High Octane Fuels Enabled mentioning

confidence: 99%

A System to Enable Mixing Controlled Combustion With High Octane Fuels Using a Prechamber and High-Pressure Direct Injector

2021

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“…The lean charge is ignited in a gas-scavenged prechamber. Further details regarding the the engine layout and testbed infrastructure can found in Zelenka et al 43…”

Section: Methodsmentioning

confidence: 99%

“…The lean charge is ignited in a gas-scavenged prechamber. Further details regarding the the engine layout and testbed infrastructure can found in Zelenka et al 43 The engine test bed is equipped with state-of-the-art measurement technology that enables the measurement of time-based and crank angle resolved data. Since the methodology described in this manuscript requires crank angle resolved pressure traces from MCC and PC, both chambers are separately equipped with cylinder pressure transducers.…”

Section: Methodsmentioning

confidence: 99%

Development of a zero-dimensional method for thermodynamic analysis and NOx calculation in the prechamber of a lean-burn gas engine

Oppl¹,

Pirker²,

Wohlthan³

et al. 2021

International Journal of Engine Research

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Significant improvements in the power density and efficiency of lean-burn large gas-engines with a prechamber and their high flexibility in meeting fluctuating power requirements illustrate the potential for using these engines in stationary power generation and in the transportation sector. Since these engines have comparatively low CO2 and NOx-emissions, they are seen as a promising solution to meet stricter emission standards. However, current combustion concepts for these engines must be enhanced to improve their performance and emission behavior; simulation methods play a major role in this process. It is critical to know and understand the fundamental processes and their relationships in the prechamber and main combustion chamber; conducting detailed analyses makes this possible. Zero-dimensional methods are suitable for these analyses. Due to their shorter calculation times, they allow extensive parameter variations to be investigated. Common methods in this area are limited to calculating performance and emission related values only in the main combustion chamber. Since a considerable share of NOx-emissions from high-performance lean-burn gas-engines arise in the prechamber, it is imperative to conduct a separate thermodynamic analysis of the prechamber and its interaction with the main combustion chamber. This paper presents a zero-dimensional method with which NOx-emissions from the prechamber can be calculated separately from the emissions of the main combustion chamber. To this end, it is necessary to conduct thermodynamic analyses of both the chambers and to consider their interaction. The measurement data for development and validation of this method is provided by tests on a single-cylinder engine with separate cylinder-pressure indication for both the chambers. Based on the results of the analyses, it can be determined to what extent each of the two systems is involved in the formation of nitrogen-oxides. With knowledge of the origin of NOx-emissions, measures may be enacted that reduce total NOx-emissions.

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“…Most low-carbon alternative fuels, including gasoline/ ethanol blends, have low cetane numbers relative to diesel fuel, meaning they are resistant to autoignition. Rapid autoignition of low-cetane fuels presents a challenge, however there are several technologies that are under development to enable the use of low-cetane fuels in mixing-controlled combustion, such as prechamber ignition 1,9 and diesel pilot ignition. 10 These technologies aim to allow the use of a wide variety of low-cetane fuels in mixing-controlled combustion.…”

Section: Introductionmentioning

confidence: 99%

Experimental measurements of soot formation in fuel-rich homogeneous mixtures using an optical rapid compression machine

Gross

Dempsey

Kempf

et al. 2023

International Journal of Engine Research

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Advanced combustion strategies are necessary for the use of more environmentally sustainable fuels than traditional diesel. Alcohol fuels and alcohol/gasoline blends are of particular interest as they are readily available in the marketplace. Heavy-duty engines typically use compression ignited, conventional diesel mixing controlled combustion. Mixing controlled combustion features a non-premixed diffusion flame with a wide range of local equivalence ratios, leading to potentially high rates of soot formation. This work studies the sooting behavior of iso-octane and ethanol as a function of equivalence ratio. Measurements are carried out in a rapid compression machine (RCM) and are reported for pre-ignition conditions of 10–30 bar and temperatures of 650–800 K. Theoretical equilibrium and bulk gas temperatures are calculated for both fuels. These data are used to identify the critical equivalence ratio, the lowest equivalence ratio where soot is detected with a single-pass laser extinction diagnostic. The critical equivalence ratio for iso-octane varies between 1.82 and 1.77 for compressed pressures of 10 and 20 bar, respectively. Ethanol, sometimes considered sootless, had a critical equivalence ratio between 2.37 and 2.12 for compressed pressures of 20 and 30 bar, respectively. When characterizing soot formation by oxygenated equivalence ratio, the critical equivalence ratios for ethanol approach those of iso-octane. This suggests the oxygenated nature of alcohol fuels reduces sooting tendency, but other factors such as fuel molecular structure and morphology may play a role. It was observed that ethanol will form soot at equivalence ratios only slightly higher than iso-octane, which could have implications in mixing controlled combustion. It was seen for both fuels that soot formation is pressure sensitive, with the critical equivalence ratio being inversely proportional to compressed pressure and the rate of soot formation. Future work will investigate the sooting behavior of gasoline/ethanol blends.

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Analysis of a Prechamber Ignited HPDI Gas Combustion Concept

Cited by 18 publications

References 10 publications

A System to Enable Mixing Controlled Combustion With High Octane Fuels Using a Prechamber and High-Pressure Direct Injector

A System to Enable Mixing Controlled Combustion With High Octane Fuels Using a Prechamber and High-Pressure Direct Injector

Development of a zero-dimensional method for thermodynamic analysis and NOx calculation in the prechamber of a lean-burn gas engine

Experimental measurements of soot formation in fuel-rich homogeneous mixtures using an optical rapid compression machine

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