Improvement of the Cold Start Qualities of Diesel Engines with Swirl Chambers

Urlaub, Alfred

doi:10.4271/940075

Cited by 9 publications

(4 citation statements)

References 2 publications

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“…Therefore, the fuel mixed with air forms a sufficiently ignitable mixture during the ignition delay period; further, a large premixed combustion phase is expected. 2 In this condition, the autoignition delay, which is highly dependent on the injection parameter, [3][4][5][6][7][8] the engine speed, 4,5 the fuel properties, 2,9 the combustion chamber conditions [3][4][5][6][7][8]10 and its design, 11 becomes longer owing to the reductions in the starting pressure and temperature for combustion. Simultaneously, the portion of stoichiometric air-fuel mixture is reduced with a lower combustion rate.…”

Section: Introductionmentioning

confidence: 99%

Study on the twin-pilot-injection strategies for the reduction in the exhaust emissions in a low-compression-ratio engine

Suh

2014

Proceedings of the Institution of Mechanical Engineers, Part D:

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An investigation of twin-pilot-injection strategies was performed in a low-compression-ratio engine in order to improve the combustion performance and to reduce the exhaust emissions. All tests were conducted on a modified four-cylinder test engine running on only one cylinder with a reduced compression ratio (15.3:1), and analyses of the combustion pressure, the heat release rate and the net work output in the cylinder were performed. At the same time, the reduction in the exhaust emissions such as carbon monoxide, hydrocarbons and soot under different twin-pilot-injection strategies was compared with other combustion cases (single-injection strategy and one-pilot-injection strategy). Higher combustion pressures, lower heat release rates, shorter ignition delay times, higher indicated mean effective pressures (about 2.1%) and lower coefficients of variation in the indicated mean effective pressure (approximately 29.4%) in all multiple-injection (one-pilot-injection or twin-pilot-injection) cases, which indicated improved operation of the low-compression-ratio engine, were observed. Retarded injection timing ( tp,SOE = 20–10° crank angle before top dead centre) in the twin-pilot-injection case proved to the best timing for reduction in the carbon monoxide emissions because the relatively short ignition delay with the high in-cylinder temperature enhanced the carbon monoxide oxidation rate. Twin-pilot-injection strategies formed higher hydrocarbon emissions because of the rich fuel mixture during the ignition delay time than one-pilot-injection combustion did. As more multiple injections were applied, lower nitrogen oxide emissions (up to 45.7%) were observed because the early termination of the first injection event and the restart of injection created a time interval between injections in which freshly charged air could be entrained into the flame.

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Section: Introductionmentioning

confidence: 99%

Study on the twin-pilot-injection strategies for the reduction in the exhaust emissions in a low-compression-ratio engine

Suh

2014

Proceedings of the Institution of Mechanical Engineers, Part D:

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“…Many studies have shown that the parameters that impact autoignition during cranking include residuals composition, equivalence ratio, surface temperature and the inlet charge temperature. More investigations have shown the effect of the ambient temperature [1,[29][30][31][32][33][34], injection system variables [1,30,31], cranking speed [30,31], fuel properties including volatility and cetane number [8,35], compression ratio and combustion chamber design [36]. Numerous studies have been carried out to optimize the different parameters that affect the cold start of diesel engines [37,38,39].…”

Section: Introductionmentioning

confidence: 99%

“…Several factors , such as ambient temperature and pressure [1,[5][6][7][8][9][10]11], the combustion chamber design [11,12,13], the fuel properties [14,15,16], the injection process [1,6,7,17], cranking speed [6,7,11,17], residuals composition, equivalence ratio, surface temperature and the inlet charge temperature [ 14,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40], affect the combustion process and engine-out emissions.…”

Section: Factors Affecting Cold Startmentioning

confidence: 99%

Opposing effects of recirculated gases during cranking on cold start of diesel engines

Rofail

Henein

Bryzik

2011

Proceedings of the Institution of Mechanical Engineers, Part D:

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The effect of recirculating engine-out gases into the intake manifold on the cold start of direct-injection diesel engines is investigated. Two types of recirculation are examined. The first is low-pressure recirculation of engine-out gases into the intake manifold where their rate is controlled by a gas recirculation (GR) valve installed between the exhaust and intake manifold. The second is high-pressure recirculation by restricting the flow of the engine-out gases using a butterfly (BF) valve, installed in the exhaust system after the turbocharger to increase the back pressure and the rate of recirculated gases. Since there is no combustion during cranking, these gases contain evaporated hydrocarbons and partial oxidation products, mostly formaldehyde (HCHO). Experimental investigations on a four-cylinder direct-injection diesel engine indicated that high rates of cranking gas recirculation (CGR) increase the ignition delay and lengthen the cranking period. Since higher concentrations of hydrocarbons (HC) are expected to enhance the autoignition process, it is suspected that the recirculated HCHO would have an opposite effect. These opposing effects are investigated using the ChemKin diesel cycle simulation model. The model results demonstrated the effect of HCHO on slowing the autoignition and combustion reactions.

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“…The contributing factors for the ignition and optimization of the control strategy in the cold start have been widely investigated. − To improve the cold startability of the diesel engines, many measures have been proposed to aid the cold start …”

Section: Introductionmentioning

confidence: 99%

Effects of Inlet Port Auxiliary Fuel Injection on the Startability of the Diesel Engine

Liu¹,

Su²,

Han³

et al. 2009

Energy Fuels

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The incomplete combustion and misfire of the diesel engine during the cold start may result in high hydrocarbon (HC) emissions. The effects of the auxiliary fuel injection of ether, CO, and propane on the start ignition behavior and exhaust emissions were studied in this paper. The results indicated that proper auxiliary fuel injection can promote the ignition and improve the combustion performance. Besides the good volatility, the ignitability of auxiliary fuel is also one of the most important factors that can improve the startability of the diesel engine. Propane and CO injections have negative effects on the ignitability of the start. Propane and CO injections deteriorate combustion and increase the HC emissions. When a proper amount of ether is injected into the intake port, the ignition during the start can be improved and the misfiring as well as incomplete combustion cycles are eliminated. As a result, the HC emissions decrease and particulate matter (PM) emissions reduce by more than 60%.

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Improvement of the Cold Start Qualities of Diesel Engines with Swirl Chambers

Cited by 9 publications

References 2 publications

Study on the twin-pilot-injection strategies for the reduction in the exhaust emissions in a low-compression-ratio engine

Study on the twin-pilot-injection strategies for the reduction in the exhaust emissions in a low-compression-ratio engine

Opposing effects of recirculated gases during cranking on cold start of diesel engines

Effects of Inlet Port Auxiliary Fuel Injection on the Startability of the Diesel Engine

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