Fuel Factors Affecting the High-Load Limit of a Temperature Stratified Controlled Auto-Ignition Engine

Maria, Amir; Cheng, Wai K.; Cannella, William; Kar, Kenneth

doi:10.4271/2014-01-1287

Cited by 3 publications

(4 citation statements)

References 8 publications

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“…Simulation Results. As conceptualized by Maria et al [12], the heat release rate in HCCI combustion occurs as a cascading ignition process and can be affected by three factors:…”

Section: Resultsmentioning

confidence: 99%

“…The effects of changing NVO on charge composition are discussed in detail in the Experimental Procedure section. While these new experiments were able to isolate compositional effects, the changes in IVC temperature necessary to maintain fixed combustion phasing possibly introduced thermal gradient changes between the fuels which could have potentially influenced HCCI heat release rates [11,12]. To further interpret the experimental results and separate thermal effects from fuel chemistry effects, simulation work was performed with a multiple zone balloon model (no mixing between zones) utilizing a simplified chemical kinetics mechanism.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Impact of Low Octane Primary Reference Fuel on HCCI Combustion Burn Rates: The Role of Thermal Stratification

Hagen¹,

Lavoie

Wooldridge

et al. 2017

Journal of Engineering for Gas Turbines and Power

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A new experimental method was developed which isolated charge composition effects for wide levels of internal exhaust gas recirculation (iEGR) at constant total EGR (tEGR) for homogeneous charge compression ignition (HCCI) combustion. The effect of changing iEGR was examined for both gasoline (research octane number (RON) = 90.5) and PRF40 at constant charge composition at multiple engine speeds. For this study, the charge composition was defined as the total mass of fresh air, fuel, and tEGR. Experimental results showed that for a given iEGR level, PRF40 had a reduced burn duration and higher maximum heat release rate (HRR) when compared with gasoline. PRF40 was found to have a nearly constant burn duration and HRR for a given load and CA50, largely independent of engine speed and iEGR level. Gasoline, for equivalent conditions, showed an increased burn duration at higher iEGR levels. When comparing PRF40 to gasoline at fixed combustion phasing and iEGR level, the increased HRR for PRF40 was correlated with reduced intake valve closing (IVC) temperatures. To examine the impact of thermal gradients (as distinct from fuel chemistry effects) due to IVC temperature differences, a multizone “balloon model” was used to evaluate experimental conditions. The model results demonstrated that when the in-cylinder temperature profiles between fuels were matched by adjusting wall temperature, the heat release rates were nearly identical. This result suggested the observed differences in burn rates between gasoline and PRF40 were influenced to a large degree by differences in thermal stratification and to a lesser extent by differences in fuel chemistry.

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“…Simulation Results. As conceptualized by Maria et al [12], the heat release rate in HCCI combustion occurs as a cascading ignition process and can be affected by three factors:…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Impact of Low Octane Primary Reference Fuel on HCCI Combustion Burn Rates: The Role of Thermal Stratification

Hagen¹,

Lavoie

Wooldridge

et al. 2017

Journal of Engineering for Gas Turbines and Power

View full text Add to dashboard Cite

show abstract

“…The mixture was prepared in a mixing chamber of approximately 10 times the volume of the RCM displacement. The design and operation of the mixing chamber are described in detail in the study by Maria et al 20 The mixture comprised fuel, oxygen, nitrogen, and argon. The latter was used to control the compression temperature by displacing some of the nitrogen to obtain a change in the ratio of specific heats of the mixture.…”

Section: Experimental Setup and Methodsmentioning

confidence: 99%

“…The design and operation of the mixing chamber are described in detail in Ref. [20]. The mixture comprised fuel, oxygen, nitrogen and argon.…”

Section: Mixture Preparationmentioning

confidence: 99%

A study of soot formation in a rapid compression machine at conditions representative of cold-fast-idle in spark ignition engines

Ketterer

Cheng

2018

International Journal of Engine Research

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The soot yield, defined as the ratio of the soot mass to the carbon mass in the fuel, for the homogeneous combustion of a rich fuel-air mixture has been measured in a rapid compression machine using the laser light extinction method. The temperature and pressure conditions are representative of those in spark-ignition direct-injection engines at cold-fast-idle. The fuels used are a certification gasoline (with 28% aromatic content) and a blend of the gasoline with toluene (the blend had 40% aromatic content by volume) so that the sensitivity of soot formation to the fuel aromatic content could be assessed. Beyond a threshold fuel equivalence ratio (ϕ) value, the soot yield increases exponentially with ϕ. The soot yield of the gasoline–toluene blend is four to six times higher than that of the gasoline. The soot yield decreases exponentially with temperature, by a factor of 0.58 for every 10 K increase in temperature. In the 657–695 K temperature range, the threshold ϕ value increases linearly from approximately 2.4 to 2.7, at a rate of 0.1 point per 10 K rise in temperature. This temperature dependence is insensitive to the charge density.

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The Impact of Low Octane Primary Reference Fuel on HCCI Combustion Burn Rates: The Role of Thermal Stratification

Hagen¹,

Lavoie

Wooldridge

et al. 2016

ASME 2016 Internal Combustion Engine Division Fall Technical Conference

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A new experimental method was developed which isolated charge composition effects for wide levels of internal EGR (iEGR) at constant total EGR (tEGR) for negative valve overlap (NVO) homogeneous charge compression ignition (HCCI) combustion. Using this method, the effect of changing iEGR was examined for both research grade gasoline (RON = 90.5) and PRF40 across multiple engine speeds and at constant charge composition. For this study, the charge composition was defined as the total mass of fresh air, fuel and tEGR. Comparison also was made between the two fuels at a fixed iEGR level to isolate, independent of compositional effects, the effect of a low octane fuel on HCCI burn rates. From the experimental results, for all engine speeds, for a given iEGR level, PRF40 was found to have a reduced burn duration and higher maximum heat release rate (HRR) compared with gasoline. PRF40 was found to have a nearly constant burn duration and HRR for a given load and CA50, largely independent of engine speed and iEGR level. Gasoline, for equivalent conditions, showed an increased burn duration at higher iEGR levels. When comparing PRF40 to gasoline at fixed speed, combustion phasing and iEGR level, the increase in HRR was found to coincide with reduced intake valve closing (IVC) temperatures necessary to maintain constant combustion phasing for the PRF40. The reduced IVC temperature for PRF40 reduced the thermal stratification in-cylinder compared with gasoline and may have been the cause of this change. To examine the impact of thermal gradients relative to fuel chemistry, a multi-zone “balloon model” was used to evaluate experimental conditions. The model used a reduced chemical kinetic mechanism for PRFs with PRF87 representing gasoline. The results of the model demonstrated that when the in-cylinder temperature profiles between PRF40 and PRF87 were matched by adjusting wall temperature, the heat release rates were nearly identical. This result suggested the observed differences in burn rates between gasoline and PRF40 were influenced to a large degree by differences in thermal stratification, and to a lesser extent by differences in fuel chemistry.

show abstract

Fuel Factors Affecting the High-Load Limit of a Temperature Stratified Controlled Auto-Ignition Engine

Cited by 3 publications

References 8 publications

The Impact of Low Octane Primary Reference Fuel on HCCI Combustion Burn Rates: The Role of Thermal Stratification

The Impact of Low Octane Primary Reference Fuel on HCCI Combustion Burn Rates: The Role of Thermal Stratification

A study of soot formation in a rapid compression machine at conditions representative of cold-fast-idle in spark ignition engines

The Impact of Low Octane Primary Reference Fuel on HCCI Combustion Burn Rates: The Role of Thermal Stratification

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