The Effects of Physical Factors on Ignition Delay

Lyn, W. T.; Valdmanis, E.

doi:10.4271/680102

Cited by 53 publications

(14 citation statements)

References 7 publications

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“…The higher viscosity, higher cetane number, and lower volatility of the biodiesel combine with the earlier injection timing to effect the start of combustion. Since emissions of nitrogen oxides (NO x ) generally increase with advanced timing, this effect may be partly responsible for the increase in NO x observed with biodiesel (2)(3)(4)(5)(6).…”

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confidence: 99%

Speed of sound and isentropic bulk modulus of alkyl monoesters at elevated temperatures and pressures

Tat

Gerpen

2003

J Americ Oil Chem Soc

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Biodiesel is a biodegradable, sulfur-free, oxygenated, and renewable alternative diesel fuel consisting of the alkyl monoesters of FA from vegetable oils and animal fats. Biodiesel can be used in existing diesel engines without significant modifications. However, differences in physical properties between biodiesel and petroleum-based diesel fuel may change the engine's fuel injection timing and combustion characteristics. These altered physical and chemical properties also may cause the exhaust emissions and performance to differ from the optimized settings chosen by the engine manufacturer. In particular, the density, speed of sound, and isentropic bulk modulus have a significant effect on the fuel injection system and combustion. The objective of this study was to measure these three properties for biodiesel (and the pure esters that are the constituents of biodiesel) at temperatures from 20 to 100°C and at pressures from atmospheric to 32.5 MPa. Ten different biodiesel fuels, 16 different pure FA esters, three hydrocarbons, and one diesel fuel were tested. The measured values of density, speed of sound, and isentropic bulk modulus are presented. Correlations between pressure and temperature are demonstrated. Speed of sound and isentropic bulk modulus tend to increase as the degree of unsaturation increases and as the chain length increases. However, density increased with shorter chain length and decreased with saturation.Biodiesel, an alternative diesel fuel consisting of the alkyl monoesters of FA from vegetable oils and animal fats, can be used in existing diesel engines without modifications. However, differences in physical properties between biodiesel and petroleumbased diesel fuel may change the engine's injection timing and combustion delay, thus altering the combustion timing and combustion rate. The combustion timing changes can cause exhaust emissions and performance different from the optimized settings chosen by the engine manufacturer. The properties that will have the greatest effect on the fuel injection timing are the speed of sound, the isentropic bulk modulus, and the viscosity. Monyem et al.(1) showed that for fixed injection-pump timing, the injection pressure pulse for biodiesel was 1.5-2.0°advanced from the diesel fuel baseline. The injection timing advance was at least partially due to differences in the fuel properties, such as the bulk modulus and speed of sound. Additional work on the same engine showed that changes in the pump static timing associated with the injection of the greater fuel volume needed to compensate for biodiesel's lower energy content are also responsible for the injection timing advance. The higher viscosity, higher cetane number, and lower volatility of the biodiesel combine with the earlier injection timing to effect the start of combustion. Since emissions of nitrogen oxides (NO x ) generally increase with advanced timing, this effect may be partly responsible for the increase in NO x observed with biodiesel (2-6).The objective of the current project was to m...

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confidence: 99%

Speed of sound and isentropic bulk modulus of alkyl monoesters at elevated temperatures and pressures

Tat

Gerpen

2003

J Americ Oil Chem Soc

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“…Early combustion timing causes combustion to occur closer to TDC and perhaps during the compression process, increasing the pressure, temperature, and NOx emission [64,67,68]. Combustion timing in a diesel engine is mainly affected by the injection timing, or the start of injection, and the ignition delay, which is the time between the start of injection and the start of combustion [64][65][66][67][68]. The ignition delay time is mostly affected by the fuel's cetane number.…”

Section: The Concept Map and Test Schedulementioning

confidence: 99%

“…A higher cetane number shortens the ignition delay time and advances the combustion timing. Early injection timing and higher cetane number advance the combustion timing which tends to increase the NOx emission [64][65][66][67][68]. Biodiesel has a lower energy content than diesel fuel and when a greater volume of fuel is injected to correct for this, some fuel injection pumps will advance the start of injection timing, causing an additional increase in NOx emission.…”

Section: The Concept Map and Test Schedulementioning

confidence: 99%

Investigation of oxides of nitrogen emissions from biodiesel-fueled engines

Tat

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“…Tenggang waktu dari periode injeksi solar sampai terjadinya titik api yang mula-mula disebut ignition delay. Ignition delay adalah suatu parameter yang sangat mempengaruhi dari awal sampai akhir proses pembakaran di dalam silinder mesin diesel, oleh sebab itu sangat mempengaruhi performa dan emisi gas buang mesin, sehingga dari dahulu telah banyak penelitian [1][2][3][4][5][6][7][8][9][10][11] dilakukan. Dewasa ini, telah banyak riset terhadap mesin diesel berbahan bakar ganda, yang memungkinkan bahan bakar gas (BBG), seperti; Liquified Petroleum Gas, Compressed Natural Gas, dan lain-lain, dipakai sebagai bahan bakar utama [12][13][14][15][16][17].…”

Section: Pendahuluanunclassified

Prediksi Ignition Delay Mesin Diesel Berbahan Bakar Ganda

Siagian¹,

Silaban²

2013

jtm

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ABSTRAKPada mesin diesel ada tenggang waktu antara sejak dimulainya penginjeksian solar (periode injeksi) ke dalam silinder bakar mesin, kemudian terbentuk campuran udara+embun solar sampai terjadi titik api yang mula-mula atau periode pengapian. Tenggang waktu atau keterlambatan pengapian ini disebut ignition delay. Ignition delay adalah suatu parameter yang sangat berpengaruh terhadap awal sampai akhir proses pembakaran di dalam silinder bakar mesin, oleh sebab itu sangat menentukan performa dan emisi gas buang mesin. Pada pengujian di sini, sebagai mesin berbahan bakar ganda.Bahan Bakar Gas (BBG), yaitu; propana, metana, dan hidrogen masing-masing dialirkan ke dalam silinder bakar mesin diesel konvensional, setelah bercampur dengan udara oleh sebuah mixer yang ditempatkan di dalam intake port. Kemudian bahan bakar solar disemprotkan langsung ke dalam silinder mesin dengan jumlah kecil (hanya sebagai pemicu api saja), dan ignition delay solar yang diinjeksikan tersebut dengan periode injeksi yang bervariasi dianalisis dan dievaluasi. Pada penelitian ini telah dilakukan dan ditemukan model perhitungan untuk memprediksi ignition delay, yaitu dengan menerapkan persyaratan autoignition Livengood-Wu (Livengood dan Wu, 1955). Dengan didapatkannya model perhitungan untuk memprediksi ignition delay ini maka diharapkan dapat mempermudah dan meningkatkan akurasi hasil yang didapat di dalam penelitian pada level simulasi khususnya pada bidang mesin diesel.Kata kunci: Keterlambatan pengapian, periode injeksi, periode pengapian, prediksi, bahan bakar ganda. Livengood-Wu (Livengood and Wu, 1955 ABSTRACT In diesel engines there is the lag time between injection of diesel fuel since the beginning (injection period) into the cylinder combustion engine, then formed a mixture of air +moisture diesel until there is a point which first fire or ignition period. The grace period or ignition delay is called the ignition delay. Ignition delay is a parameter that greatly affects the beginning to the end of the process of fuel combustion in the engine cylinder and therefore determine the performance and engine exhaust emissions. In testing here, as a dual-fuel engines, fuel gas, namely propane, methane, and hydrogen respectively supplied to the cylinder combustion conventional diesel engines, after mixing with air by a mixer placed in the intake ports. Then the diesel fuel is sprayed directly into the cylinder machine with a small amount (just as the trigger fires only), and the ignition delay of diesel fuel is injected with variable injection period is analyzed and evaluated. In this study has been carried out and found the model calculations to predict the ignition delay, ie by applying the requirements of auto ignition PENDAHULUANPada mesin diesel ada tenggang waktu antara sejak dimulainya penginjeksian solar (periode injeksi), kemudian meningkatnya tekanan dan temperatur sampai batas tertentu akibat gerakan menekan dari piston maka campuran udara + solar di dalam ruang bakar mesin mengalami terjadinya titik api yang mula-mula sehin...

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The Effects of Physical Factors on Ignition Delay

Cited by 53 publications

References 7 publications

Speed of sound and isentropic bulk modulus of alkyl monoesters at elevated temperatures and pressures

Speed of sound and isentropic bulk modulus of alkyl monoesters at elevated temperatures and pressures

Investigation of oxides of nitrogen emissions from biodiesel-fueled engines

Prediksi Ignition Delay Mesin Diesel Berbahan Bakar Ganda

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