A Thermodynamic Study on Boosted HCCI: Experimental Results

Kulzer, André; Nier, Tobias; Karrelmeyer, Roland

doi:10.4271/2011-01-0905

Cited by 27 publications

(11 citation statements)

References 10 publications

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“…The first is using a hybrid mode of combustion in which a portion of the fuel energy is consumed by a propagating flame front initiated by a spark, with the remainder of the fuel energy being consumed by a volumetric HCCI-like combustion event, known both as spark-assisted HCCI (SA-HCCI) and spark-assisted compression ignition (SACI) [7,8,9,10,11]. The second is to implement a boosted air handling system so that the required dilution for HCCI can be maintained as the engine load is increased [12,13,14,15,16,17]. This study focuses on the latter strategy of load range expansion, specifically with the use of DI fueling and a NVO valve train strategy used to control combustion phasing and noise.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Engine Control Authority on HCCI Combustion as the High Load Limit is Approached

Szybist

Edwards

Foster

et al. 2013

SAE Int. J. Engines

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In this study the authority of the available engine controls are characterized as the high load limit of homogeneous charge compression ignition (HCCI) combustion is approached. A boosted single-cylinder research engine is used and is equipped with direct injection (DI) fueling, a laboratory air handling system, and a hydraulic valve actuation (HVA) valve train to enable negative valve overlap (NVO) breathing. Results presented include engine loads from 350 to 650 kPa IMEP net and manifold pressure from 98 to 190 kPaa. It is found that in order to increase engine load to 650 kPa IMEP net , it is necessary to increase manifold pressure and external EGR while reducing the NVO duration. While both are effective at controlling combustion phasing, NVO duration is found to be a "coarse" control while fuel injection timing is a "fine" control. NO X emissions are low throughout the study, with emissions below 0.1 g/kW-h at all boosted HCCI conditions, while good combustion efficiency is maintained (>96.5%). Net indicated thermal efficiency increases with load up to 600 kPa IMEP net , where a peak efficiency of 41% is achieved. Parametric investigations reveal that increasing exhaust gas recirculation (EGR) at a constant intake manifold pressure (MAP) and increasing MAP at a constant external EGR rate both retard combustion phasing. It is also found that combustion phasing becomes increasingly sensitive to NVO duration as engine load increases. Finally, comparisons are made between commonly used noise metrics. It is found that compared to the AVL combustion noise meter, ringing intensity (RI) significantly underestimates combustion noise under boosted HCCI conditions. CITATION: Szybist, J., Edwards, K., Foster, M., Confer, K. et al., "Characterization of Engine Control Authority on HCCI Combustion as the High Load Limit is Approached," SAE Int. J. Engines 6(1):2013,

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Section: Introductionmentioning

confidence: 99%

Characterization of Engine Control Authority on HCCI Combustion as the High Load Limit is Approached

Szybist

Edwards

Foster

et al. 2013

SAE Int. J. Engines

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“…Even though the intake pressure was limited to 2 bar in this study, higher boost levels up to 3 bar are currently being investigated [13]. Even though the intake pressure was limited to 2 bar in this study, higher boost levels up to 3 bar are currently being investigated [13].…”

Section: Overall Assessment the State Equation Methods Hasmentioning

confidence: 98%

Assessment of Residual Mass Estimation Methods for Cylinder Pressure Heat Release Analysis of HCCI Engines With Negative Valve Overlap

Ortiz-Soto

Vávra

Babajimopoulos

2012

Journal of Engineering for Gas Turbines and Power

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Increased residual levels in homogeneous charge compression ignition (HCCI) engines employing valve strategies such as recompression or negative valve overlap (NVO) imply that accurate estimation of residual gas fraction (RGF) is critical for cylinder pressure heat release analysis. The objective of the present work was to evaluate three residual estimation methods and assess their suitability under naturally aspirated and boosted HCCI operating conditions: (i) the simple state equation method employs the ideal gas law at exhaust valve closing (EVC); (ii) the Mirstcy method assumes isentropic exhaust process; and (Hi) the Fitzgerald method models in-cylinder temperature from exhaust valve opening (EVO) to EVC by accounting for heat loss during the exhaust process and uses measured exhaust temperature for calibration. Simulations with a calibrated and validated "virtual engine" were performed for representative HCCI operating conditions of engine speed, fuel-air equivalence ratio, NVO and intake pressure (boosting). The state equation method always overestimated RGF by more than 10%. The Mirsky method was most robust, with average errors between 3-5%. The Fitzgerald method performed consistently better, ranging ffom no error to 5%, where increased boosting caused the largest discrepancies. A sensitivity study was also performed and determined that the Mirsky method was most robust to possible pressure and temperature measurement errors. Virtual Engine ApproachIn-depth analysis of residual estimation methods requires engine data over a wide range of operating conditions. Moreover, validation of these methods requires benchmark results of incylinder content, temperature, and properties that are difficult to measure directly. For these reasons, it was opted to perform the analysis using a virtual engine, i.e., a model of the actual engine. The virtual engine is calibrated and validated against experimental results to ensure representative behavior and then employed as the main data source for the investigation. As with any model-based approach, discrepancies are expected, but given the conceptual level of the present study, proper trend-wise performance of the model is considered of greater interest than obtaining an exact Journal of Engineering for Gas Turbines and Power

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“…Canakci [11] applied a moderate boost of up to approximately 0.14 MPa to gasoline port injected HCCI engine and found that increase of the intake pressure at constant fuelling enabled a substantial reduction in NO X emissions; at the same time, however, an excessive PRR was noted. However, application of high boost pressure of up to 0.3 MPa allowed Kulzer et al [12,13] to conclude that increasing in-cylinder charge dilution by air enables substantial reduction in PRR. It should be noted, however, that achieving such high boost pressure in CAI engine operated in the NVO mode requires a mechanical boost device, which would reduce overall efficiency of the engine.…”

Section: Introductionmentioning

confidence: 99%

Late direct fuel injection for reduced combustion rates in a gasoline controlled auto-ignition engine

Hunicz¹,

Mikulski²,

Gęca³

et al. 2018

THERM SCI

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Homogeneous charge compression ignition concepts despite high efficiency and ultra-low nitrous oxides emissions, suffer from week controllability and load range limited by excessive pressure rise rates. In the present work, controlled auto-ignition is achieved via direct injection of gasoline into the exhaust gasses recompressed during negative valve overlap phase. Single cylinder engine experiments are designed to explore the potential of additional late post injection strategies for pressure rise rate and peak pressure suppressing. For two mixture strengths, fuel distribution is varied between 3 gasoline injection events. In-depth combustion analysis is supported by emission measurement results. Increasing the amount of gasoline, post-injected during the main compression event, was proven to be an effective measure for reducing pressure rise rates, with over 50% reduction potential. The regulation capability however, is limited by typical tread-offs between stratified and homogenous fuelling concepts. Using post injection strategy results in decreased hydrocarbon emissions, but causes rapid increase in carbon monoxide and particulate matter emissions. Nitrous oxide increase rate is dependent on mixture strength with significantly higher sensitivities during lean operation.

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A Thermodynamic Study on Boosted HCCI: Experimental Results

Cited by 27 publications

References 10 publications

Characterization of Engine Control Authority on HCCI Combustion as the High Load Limit is Approached

Characterization of Engine Control Authority on HCCI Combustion as the High Load Limit is Approached

Assessment of Residual Mass Estimation Methods for Cylinder Pressure Heat Release Analysis of HCCI Engines With Negative Valve Overlap

Late direct fuel injection for reduced combustion rates in a gasoline controlled auto-ignition engine

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