Understanding optimal engine operating strategies for gasoline-fueled HCCI engines using crank-angle resolved exergy analysis

Saxena, Samveg; Shah, Nihar; Bedoya, Iván D.; Phadke, Amol

doi:10.1016/j.apenergy.2013.09.056

Cited by 60 publications

(28 citation statements)

References 17 publications

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“…The engine block heat loss was calculated by using Equation (16) and exergy was calculated by using Equation (17).…”

Section: Second Law Analysismentioning

confidence: 99%

“…First a combustion timing was set for optimal efficiency then the changes in the components of the loss mechanism were studied for early and late combustion condition. The results suggest that the equivalence ratio should be maintained at relatively high values across most operating conditions while intake pressure is used to vary engine load [17]. Sezer et al examined the effects of the SI engine's charge properties on the exergy equilibrium.…”

Section: Introductionmentioning

confidence: 99%

“…Multiple injection strategies are widely used in CI engines to reduce NOx emission [17]. Therefore, effect of working parameters of multiple injection strategies such as dwell time, main and pre injection timing, mass proportion and injection pressure on exergy has created a new research field.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Comparative Study on Energy and Exergy Analyses of a CI Engine Performed with Different Multiple Injection Strategies at Part Load: Effect of Injection Pressure

Özkan

2015

Entropy

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Abstract:In this study, a four stroke four cylinder direct injection CI engine was run using three different injection pressures. In all measurements, the fuel quantity per cycle, the pre injection and main injection timing, the boost pressure and the engine speed were kept constant. The motor tests were performed under 130, 140 and 150 MPa rail pressure. During the theoretical part of the study, combustion, emission, energy and exergy analysis were made using the test results. An increase in the injection pressure increases combustion efficiency. The results show that combustion efficiency is not enough by itself, because the increase in the power need of the injection pump, decreases the thermal efficiency. The increase in the combustion temperature, increases the cooling loss and decreases the exergetic efficiency. In addition, the NOx emissions increased by 12% and soot emissions decreased 44% via increasing injection pressure by 17%. The thermal and exergetic efficiencies are found inversely proportional with injection pressure. Exergy destruction is found independent of the injection pressure and its value is obtained as ~6%.

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“…The engine block heat loss was calculated by using Equation (16) and exergy was calculated by using Equation (17).…”

Section: Second Law Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Comparative Study on Energy and Exergy Analyses of a CI Engine Performed with Different Multiple Injection Strategies at Part Load: Effect of Injection Pressure

Özkan

2015

Entropy

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“…Previous efforts found the optimal CA50 within 2-10°ATDC for the best tradeoff between efficiency, emissions, and maximum brake torque [69,[90][91][92]. We selected 3 ± 2°ATDC based on similar values used in numerous recent studies [23, 50-52, 75, 76], which falls on the early side of the optimal timing range.…”

Section: Sensitivity To Ca50 Value and Tolerancementioning

confidence: 99%

Investigation of the LTC fuel performance index for oxygenated reference fuel blends

Niemeyer

Daly

Cannella

et al. 2015

Fuel

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A new metric for ranking the suitability of fuels in LTC engines was recently introduced, based on the fraction of potential fuel savings achieved in the FTP-75 light-duty vehicle driving cycle. In the current study, this LTC fuel performance index was calculated computationally and analyzed for a number of fuel blends comprised of n-heptane, isooctane, toluene, and ethanol in various combinations and ratios corresponding to octane numbers from 0 to 100. In order to calculate the LTC index for each fuel, computational driving cycle simulations were first performed using a typical light-duty passenger vehicle, providing pairs of engine speed and load points. Separately, for each fuel blend considered, single-zone naturally aspirated HCCI engine simulations with a compression ratio of 9.5 were performed in order to determine the operating envelopes. These results were combined to determine the varying improvement in fuel economy offered by fuels, forming the basis for the LTC fuel index. The resulting fuel performance indices ranged from 36.4 for neat n-heptane (PRF0) to 9.20 for a three-component blend of n-heptane, isooctane, and ethanol (ERF1). For the chosen engine and chosen conditions, in general lower-octane fuels performed better, resulting in higher LTC fuel index values; however, the fuel performance index correlated poorly with octane rating for less-reactive, higher-octane fuels.

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“…HCCI is an alternative operating mode for an internal combustion engine and is considered as one potential solution to solve this problem [4,5] besides that HCCI also can operated on wide range of fuel [3]. HCCI engines operates at higher thermal efficiency as high as 50% [6] than gasoline and diesel engines [7,8] with similar displacement volume, while it also emits ultra-low particle matter (PM) and nitrogen oxides (NOx) emissions [9]. These emission reductions are achieved by physically separating the injection events from the onset of combustion, therefore makes ignition delayed long enough to ensure a lean and nearly-homogenous air-fuel mixture.…”

Section: Introductionmentioning

confidence: 99%

Numerical modeling on homogeneous charge compression ignition combustion engine fueled by diesel-ethanol blends

et al. 2016

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Abstract. This paper investigates the performance and emission characteristics of HCCI engines fueled with oxygenated fuels (ethanol blend). A modeling study was conducted to investigate the impact of ethanol addition on the performance, combustion and emission characteristics of a Homogeneous Charge Compression Ignition (HCCI) engine fueled by diesel. One dimensional simulation was conducted using the renowned commercial software for diesel and its blend fuels with 5% (E5) and 10% ethanol (E10) (in vol.) under full load condition at variable engine speed ranging from 1000 to 2750 rpm with 250 rpm increment. The model was then validated with other researcher's experimental result. Model consists of intake and exhaust systems, cylinder, head, valves and port geometries. Performance tests were conducted for volumetric efficiency, brake engine torque, brake power, brake mean effective pressure, brake specific fuel consumption, and brake thermal efficiency, while exhaust emissions were analyzed for carbon monoxide (CO) and unburned hydrocarbons (HC. The results showed that blending diesel with ethanol increases the volumetric efficiency, brake specific fuel consumption and brake thermal efficiency, while it decreases brake engine torque, brake power and brake mean effective pressure. In term of emission characteristics, the CO emissions concentrations in the engine exhaust decrease significantly with ethanol as additive. But for HC emission, its concentration increase when apply in high engine speed. In conclusion, using Ethanol as fuel additive blend with Diesel operating in HCCI shows a good result in term of performance and emission in low speed but not recommended to use in high speed engine. Ethanol-diesel blends need to researched more to make it commercially useable.

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Understanding optimal engine operating strategies for gasoline-fueled HCCI engines using crank-angle resolved exergy analysis

Cited by 60 publications

References 17 publications

A Comparative Study on Energy and Exergy Analyses of a CI Engine Performed with Different Multiple Injection Strategies at Part Load: Effect of Injection Pressure

A Comparative Study on Energy and Exergy Analyses of a CI Engine Performed with Different Multiple Injection Strategies at Part Load: Effect of Injection Pressure

Investigation of the LTC fuel performance index for oxygenated reference fuel blends

Numerical modeling on homogeneous charge compression ignition combustion engine fueled by diesel-ethanol blends

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