A B A blend Bgr.xjtu.edu.cn/upload/PUB.1643.4/Combustion... · diameters smaller than 10 and 2.5 m m respectively). practical measures for the improvement of combustion Almost all

1011

Combustion characteristics and heat release analysisof a compression ignition engine operating on adiesel/methanol blend

Z H Huang1*, H B Lu2, D M Jiang2, K Zeng2, B Liu2, J Q Zhang2 and X B Wang21State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, People’s Republicof China2School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an, People’s Republic of China

Abstract: A stabilized diesel/methanol blend was developed and the combustion characteristics andheat release analysis of this blend was carried out in a compression ignition engine. The study showedthat the increase in the methanol mass fraction will result in an increase in the heat release rate inthe premixed burning phase and shorten the combustion duration of the diffusive burning phase.Ignition delay increases with the increase in the methanol mass fraction and the behaviour is moreobvious at low engine load and high engine speed. The rapid-burn duration varies little with themethanol mass fraction and the total combustion duration decreases with the increase in the methanolmass fraction. At a low engine speed, the centre of heat release curve tends to be close to the topdead centre (TDC), with an increase in the methanol mass fraction at all engine loads and fuel deliveryadvance angles, the maximum rate of pressure rise and the maximum rate of heat release increasewith the increase in the methanol mass fraction. At a high engine speed, the centre of the heat releasecurve closes to TDC at high engine load and will depart from TDC at low engine load. The maximumrate of pressure rise and heat release gives an increasing trend with the increase of methanol massfraction at high engine loads. The maximum cylinder pressure increases with the increase of themethanol mass fraction. The presence of oxygen reduces the peak pressure, but the reduction wasfound to be insensitive to the proportion of oxygen within the 6–11 per cent range of testing.

Keywords: combustion, heat release analysis, diesel/methanol blends, compression ignition engine

maximum rate of heat release withNOTATION AdQBdQ B

maxcrank angle

A wall area (m2)heat transfer rate with crank angleATDC after top dead centre AdQw

dQ Bb.m.e.p brake mean effective pressure (MPa)BTDC before top dead centre

hc heat transfer coefficient (J/m2 s K)Cp

constant pressure specific heatHu lower heating value (MJ/kg)

(kJ/kg K)H wt% mass fraction of hydrogen in the fuel

CV

constant volume specific heat (kJ/kg K)blend

C wt% mass fraction of carbon in the fuelm mass of cylinder gases (kg)

blendO wt% mass fraction of oxygen in the fuel

maximum rate of pressure rise withblendAdp

dQBmax

crank anglep cylinder gas pressure (MPa)pmax maximum cylinder gas pressure (MPa)heat release rate with crank angleAdQB

dQ B R gas constant (J/kg K)T mean gas temperature ( K)Tmax maximum mean gas temperature ( K)The MS was received on 16 June 2003 and was accepted after revision

for publication on 16 April 2004. Tw wall temperature ( K)* Corresponding author: State Key Laboratory of Multiphase Flow in

TDC top dead centrePower and Engineering, Institute of Internal Combustion Engines, Xi’anJiaotong University, Xi’an, 710049, People’s Republic of China. V cylinder volume (m3)

D11003 © IMechE 2004 Proc. Instn Mech. Engrs Vol. 218 Part D: J. Automobile Engineering

1012 Z H HUANG, H B LU, D M JIANG, K ZENG, B LIU, J Q ZHANG AND X B WANG

ge effective thermal efficiency istics of diesel/dimethyl carbonate (DMC) in a com-pression ignition engine [9]. Wang et al. [10] conductedhfd fuel delivery advance angle (CA degrees

BTDC) research on combustion of oxygenated fuel with exhaustgas recirculation (EGR) while Murayama et al. [11]Qc crank angle of the centre of heat release

curve (CA degrees ATDC) studied the emissions and combustion with EGR andDMC. In the study, they used external EGR, whichQe crank angle of heat release ending

(CA degrees ADTC) was measured by determining the ratio of CO2 con-centration in the intake port to that in the exhaust port.Qs crank angle of heat release beginning

(CA degrees BTDC) Ajav et al. [12] studied the diesel/ethanol blends foremission reduction and Bertoli et al. [13], Miyamotoet al. [14] and Akasaka and Sakurai [15] also conductedresearch on diesel combustion improvement and emission1 INTRODUCTIONreduction by using various types of oxygenated fuelblends.Reduction of engine emissions is a major research

aspect in engine development. With increasing concern Methanol is regarded as one of the promising alternativefuels or an oxygen additive in a diesel engine, with itsin environmental protection and stringent exhaust gas

regulations, it is difficult to simultaneously reduce NOx

advantages of low price and high oxygen fraction.However, due to the difficulty in forming a stabilizedand smoke in a normal diesel engine due to the trade-off

curve between NOx

and smoke. The promising methods diesel/methanol blend, limited research has been under-taken and previous work has been mainly concentratedto solve this problem are to use clean fuel like natural

gas [1, 2], oxygenated alternative fuels like alcohol or on the application of diesel/ethanol blend in the com-pression ignition engine [16, 17]. Therefore, more researchdimethyl ether (DME) [3–5] or to add oxygenated fuels

to diesel fuel in order to provide more oxygen during is needed to find out how the diesel/methanol blend canbe utilized more effectively in the compression ignitioncombustion. It is well known that diesel engine com-

bustion produces particulate matter (PM), in which engine by clarifying the basic combustion and emissioncharacteristics and providing an approach for attainingthe fine particulates are believed to be the main factor

accounting for diseases of the human respiratory tract. a stabilized diesel/methanol blend with some solvent. Thestudy is expected to supply more information for enginesThe fine particles most likely to cause adverse health

effects are PM10 and PM2.5 (particles with aerodynamic operating on the oxygenated fuels and provide morepractical measures for the improvement of combustiondiameters smaller than 10 and 2.5 mm respectively).

Almost all fine particulates are generated as a result of and the reduction of emissions.Based on previous study by the authors, the objectivecombustion processes, diesel-fuelled engine combustion

and various industrial processes. PM can be reduced when of this study is to develop a stabilized diesel/methanolblend by adding specific solvents and then to investigatesufficient oxygen is available in combustion chamber, thus

utilization of oxygen-contained fuels in diesel engines is the combustion characteristics and heat release processof a compression ignition engine operating on the diesel/expected to decrease PM10 and PM2.5.

In the utilization of pure oxygenated fuels, Fleisch methanol blends.et al. [3], Kapus and Ofner [4] and Sorenson andMikkelsen [5] have studied dimethyl ether (DME) inthe modified diesel engine, and their results showed that 2 TEST ENGINE AND FUEL PROPERTIESthe engine could achieve ultra-low emissions without afundamental change in the combustion system. Huang The specifications of the test engine are listed in Table 1.

Three kinds of diesel/methanol blends were designated foret al. [6 ] investigated the combustion and emissioncharacteristics in a compression ignition engine with study. Due to the low solubility of methanol in the diesel

fuel, a solvent consisting of oleic and iso-butanol wasDME and found that the engine had a high thermalefficiency, a short premixed combustion phase and a fast added to diesel/methanol blends to form a stabilized blend.diffusive combustion phase. It had the advantage of lownoise with smoke-free combustion. Kajitani et al. [7]

Table 1 Engine specificationsstudied the DME-fuelled engine where the injectiontiming was retarded in order to reduce both smoke

Bore (mm) 100and NO

xemissions. Stroke (mm) 115

Displacement (cm3) 903Practically, adding some oxygenated compounds toCompression ratio 18diesel fuel to reduce engine emissions without engineShape of combustion chamber v shape in the bottom of the

modification seems to be more attractive. Huang et al. bowl-in-pistonRated power/speed 11 kW/2300 r/mintested gasoline/oxygenate blends in a spark-ignited engineNozzle hole diameter (mm) 0.3and achieved satisfactory results in emission reduction [8]Number of nozzle holes 4

and investigated the combustion and emission character-

D11003 © IMechE 2004Proc. Instn Mech. Engrs Vol. 218 Part D: J. Automobile Engineering

1013COMBUSTION CHARACTERISTICS AND HEAT RELEASE ANALYSIS

Table 2 Fuel properties of diesel, methanol, solvents and blended fuel constitutions

SolventsBase fuel: Blended fuel:diesel methanol Oleic Iso-butanol

Chemical formula C10.8H18.7 CH3OH C18H34O2 C4H10OMole weight (g) 148.3 32 282 74Density (g/cm3) 0.86 0.796 0.8905 0.802Lower heating value (MJ/kg) 44.40 19.68 38.65 33.14Heat of evaporation (kJ/kg) 260 1110 200 580Self-ignition temperature (°C) 200–220 470 335 385Cetane number 45 5 40 10C wt% 86 37.5 76.6 64.8H wt% 14 12.5 12 13.5O wt% 0 50 11.4 21.7Blended fuel 1 (wt%) 79.86 8.96 10.1 1.08Blended fuel 2 (wt%) 71.28 13.33 14.47 0.92Blended fuel 3 (wt%) 63.94 17.66 16.6 1.8

The properties of oleic indicate that it is a better surface fraction in the fuel blends ranges from 5.87 to 11.1, asshown in Fig. 2. It can be seen that the oxygen in theactivator [18] as well as being cheap and able to be

supplied in large quantities. It was proved by the authors fuel blends was mainly contributed by the addition ofmethanol, although the mass fraction of methanol andto be beneficial to the formation of diesel/methanol

blends. Iso-butanol has a relatively high solubility in solvent is the same, so it is reasonable to regard theinfluence of oxygen in the fuel blends as being a resultdiesel fuel and can be completely soluble in methanol

for any ratio. It has been reported as a solvent for diesel/ of the addition of methanol. The fuel properties showthat methanol has a high oxygen content while the heatethanol blends [18]. Thus, the study selected oleic and

iso-butanol as the solvents for diesel/methanol blends value is less and the cetane number is low compared tothe diesel fuel. With respect to the autoignition temper-and successfully developed stabilized blends. The fuel

properties and constitutions of three blends are given in ature of the blended fuel, the study did not record anymeasurements and therefore could not give a definiteTables 2 and 3 and Fig. 1 respectively.

Methanol and oleic were first blended together answer for the variation of autoignition temperaturewith methanol addition. However, it is estimated thatbefore being blended with diesel fuel; a small amount

of iso-butanol was found to increase the stability and the autoignition temperature of the blended fuel maytend to increase with methanol increase due to a highhomogeneity of the diesel/methanol blend. The oxygenautoignition temperature of methanol.

In the experiment, the three fuel blends with differentTable 3 Fuel properties of the diesel/methanol blended fuelmethanol proportions were injected directly into the com-

Blended Blended Blended bustion chamber before TDC. Meanwhile, combustionfuel 1 fuel 2 fuel 3

characteristics were analysed at the same brake meanLower heating value (MJ/kg) 41.73 39.89 38.64 effective pressure (b.m.e.p.). These parameters were thenHeat of evaporation (kJ/kg) 333.53 367.57 405.94 compared with those of pure diesel combustion in orderCetane number 40.41 38.4 36.21

to clarify the effect of the oxygenate additive on com-C wt% 80.47 77.98 75.5H wt% 13.66 13.5 13.4 bustion. Fuel is injected directly into the cylinder beforeO wt% 5.87 8.52 11.1 TDC from the diesel injector. No coking phenomenon,

Fig. 2 Oxygen mass fraction in fuel blendsFig. 1 Constitution of the fuel blends



no wearing and no corrosion were found within the CA and the acquisition process covered 254 completedperiod of the experiment. However, a further durability cycles, the average value of these 254 cycles being out-study on the wear and possible corrosion is unavoidable putted as the pressure data used for calculation of thebefore its application in diesel engines. combustion parameters. The b.m.e.p was calculated from

engine power, speed and configuration specifications.The thermodynamic model is used to calculate the

3 RESULTS AND DISCUSSION thermodynamic parameters in this paper. The modelneglects leakage through the piston rings [19], so the

3.1 Instrumentation and method of calculation energy conservation in the cylinder is written as follows:

The cylinder pressure was recorded by a piezoelectrictransducer with a resolution of 10 Pa and the dynamic dQB

dQ−

dQWdQ=

d(mu)

dQ+p

dV

dQtop dead centre (TDC) was determined by motoring.The crank angle (CA) signal was obtained from anangle-generating device mounted on the main shaft. The =mC

VdT

dQ+mT

dCV

dQ+p

dV

dQ(1)

signal of cylinder pressure was acquired for every 0.5°

Fig. 3 Heat release rate of the fuel blends at 1500 r/min



The gas state equation is where the heat transfer rate is given by

pV=mRT (2) dQWdQ=hcA(T−TW) (5)

The variation of the gas state equation with crank angleThe heat transfer coefficient hc uses the correlationis given byformula given by Woschni in reference [20]. C

pand C

Vare temperature-dependent parameters; their formulae

pdV

dQ+V

dp

dQ=mR

dT

dQ(3) are also given in reference [20]. The primary source is

cylinder pressure–crank angle data. Using primary dataand the above formula, the peak pressure pmax , meanThe heat release rate dQB /dQ can be derived fromgas temperature T, maximum mean gas temperature Tmax,formulae (1) and (3) as follows:rate of pressure rise and heat release (dp/dQ), (dQB /dQ)and its maximum value (dp/dQ)max or (dQB /dQ)max candQB

dQ=p

Cp

R

dV

dQ+

CV

V

R

dp

dQ+mT

dCV

dQ+

dQWdQ

(4)be calculated.

Fig. 4 Heat release rate of the fuel blends at 2000 r/min



The ignition delay is the time interval from the heat release curve is determined by the following formula:beginning of the nozzle valve lift to the beginning of thetiming of pressure rising after fuel injection (the crankangle of pressure starts rising after fuel injection); the

Qc=P QeQs

dQBdQQ dQ

P QeQs

dQBdQ

dQ

(6)rapid combustion duration is the time interval fromthe beginning of pressure rising to the ending of rapidpressure rising (the crank angle of dp/dQ obviously dropsto a low value and later gives a slow decrease); the total in which Qs is the crank angle at the beginning of the

heat release and Qe is the crank angle at the end ofcombustion duration is the time interval from thebeginning of heat release (the crank angle of the heat the heat release.

Figure 3 illustrates the heat release rates of the diesel/release curve starts rising after fuel injection) to the end-ing of heat release (the crank angle of the heat release methanol blends, dQB /dQ, at three settings of the fuel

delivery advance angle at an engine speed of 1500 r/min.curve falls to zero). The crank angle of the centre of the

Fig. 5 Ignition delay of the fuel blends



Those for an engine speed of 2000 r/min are shown in which in turn results in a long ignition delay and anincrease in premixed combustion fuel prepared withinFig. 4. The results show that an increase in the oxygen

mass fraction (or the methanol mass fraction) will result the ignition delay period. This eventually brings aboutan increase in the heat release rate and the fraction ofin an increase in the maximum rate of heat release and

the fraction of fuel burned in the premixed combustion fuel burned in the premixed combustion phase. Althoughmore fuel is needed in the case of diesel/methanol blendsphase; the behaviour is more obvious at a high engine

load. Figures 3 and 4 also show a delay in the heat in order to achieve the same b.m.e.p., this will increasethe fuel injection duration. Furthermore, oxygen enrich-release initiating timing in the case of diesel/methanol

blends compared with that of pure diesel fuel. This delay ment by injecting oxygen-contained fuel blends willimprove the combustion in the diffusive burning phasewill increase with an increase in the methanol mass

fraction in fuel blends; the delay tends to be more obvious and can shorten the combustion duration of the diffusiveburning phase (the characteristics can be obtained in theat low engine load or at high engine speed. An increase

in the methanol mass fraction (oxygen mass fraction) late section comprising the total combustion duration,the ignition delay and the rapid burn duration).will cause a decrease in cetane number of the fuel blends,

Fig. 6 Rapid combustion duration of the fuel blends



The heat release process is almost completed at the pattern at low engine speed (1500 r/min) and a flat andlong premixed burning pattern at high engine speedposition of the same crank angle, which is another aspect

providing the evidence to support the fast diffusive burn- (2000 r/min). This can also be explained by the influenceof the ignition delay on the scale of the crank angle, asing phase in the diesel/methanol fuel blend. Since a low

engine load has a low gas temperature in the cylinder a long ignition delay will cause the combustion to beprolonged to a late stage, as shown in Fig. 4.and the ignition delay would be largely affected by cetane

number under such an environment, a relatively large Figure 5 gives the ignition delay of the diesel/methanolblends at three settings of fuel delivery advance angle.ignition delay would therefore occur at the low engine

load. The ignition delay represents preparation for the Generally speaking, the ignition delay showed an increasewith the increase in the methanol mass fraction in blendsphysical and chemical pre-flame processes and does not

vary very much in the time-scale (ms). However, it will and the behaviour is more obvious at low engine loadand high engine speed. As explained above, lowering ofincrease with the increase in engine speed for the scale

of the crank angle. At low engine load, the heat release the cetane number with an increase in methanol additionis responsible for the increase in the ignition delay.curves also revealed a sharp and short premixed burning

Fig. 7 Total combustion durations of the fuel blends



Moreover, the increase in the heat of evaporation of the injected in the case of oxygen-containing fuel blends, theimprovement of mixing and combustion due to oxygenblends will cause a temperature drop of the cylinder

gases and an increase in the ignition delay. For a specific enrichment could also ensure a fast premixed combustion.For a specific fuel, the duration of rapid burn shows anfuel, the ignition delay increases with the decrease of

engine load (b.m.e.p.), which would be due to the influence increase with an increase in b.m.e.p.; the increase inthe duration of fuel injection is responsible for thisof the cylinder gas temperature within the ignition delay

period as the gas temperature is lower at low engine behaviour. The total combustion duration decreases withan increase in the methanol mass fraction in the diesel/load than at high engine load. The long ignition delay

(crank angle scale) at high engine speed is due to the methanol blends at low loads and engine speeds (Fig. 7),indicating that the addition of methanol in diesel fuelfact that high engine speed will correspond to a large

crank angle under the same time-scale (ms). With respect could promote the combustion and shorten the com-bustion duration. The decrease in total combustionto the rapid burn duration (shown in Fig. 6), it was

found that the methanol mass fraction had little influence duration would be mainly due to the decrease in thediffusive burning phase as the ignition delay increases,on the rapid burn duration. Although more fuel is

Fig. 8 Centre of the heat release curve of the fuel blends



causing fewer variations in rapid burn duration to be angles. The fast combustion rates at the premixed burn-ing phase and the subsequent diffusive burning phaseobserved. As explained above in the discussion of heat

release, the fast combustion rate in the premixed com- cause the centre of the heat release curve to be closeto TDC. Another is the case at high engine speedbustion phase as well as in the subsequently diffusive

combustion phase results in a decrease in total combustion (2000 r/min), where Qc shows a decrease with the increasein the methanol mass fraction at high engine loadduration of the diesel/methanol blends.

Figure 8 shows the position (crank angle) of the centre (b.m.e.p.= 0.608 MPa), an increase at low engineload (b.m.e.p.=0.208 MPa) and is invariable at middleof the heat release curve Qc of the diesel/methanol blends

at three settings of fuel delivery advance angle. The engine load (b.m.e.p.=0.392 MPa). Since the increaseof the ignition delay is more obvious in the case ofbehaviour of Qc versus the methanol mass fraction can

be classified into two types. One is the case at low engine high engine speed (2000 r/min) and low engine load(b.m.e.p.=0.208 MPa), the heat release curve would bespeed (1500 r/min), where the centre of the heat release

curve shows a decrease with the increase in the methanol extended to a late phase (as shown in Fig. 4) and causesthe centre of the heat release curve to extend to a latemass fraction at all engine loads and fuel delivery advance

Fig. 9 Maximum cylinder gas pressure of the fuel blends



phase. However, at high engine load, the ignition delay behavior can be observed at the middle and high loadsfor all engine speeds. Since Pmax is related to the amountgives little variation with the methanol addition. Thus,

the fast premixed combustion and diffusive combustion of prepared fuel within the ignition delay period (premixedburning phase) and the lowering of gas temperature duewould cause the centre of the heat release curve to be

close to TDC. to fuel evaporation, an increase in the methanol massfraction will increase the fraction of fuel in the premixedFigure 9 shows the maximum cylinder gas pressure of

the diesel/methanol blends Pmax at three settings of fuel combustion phase and then causes an increase in Pmax .The calculated mean gas temperature remains relativelydelivery advance angle. The calculated maximum mean

gas temperature Tmax versus the oxygen mass fraction constant with the methanol mass fraction, which suggeststhat methanol addition has little influence on the maxi-is shown in Fig. 10. Except at low engine load, Pmax

shows an increase with the increase in the methanol mum mean gas temperature at the same b.m.e.p. Tmaxreaches its peak value at a later phase than that ofmass fraction in diesel/methanol blends. The presence of

oxygen reduces the peak pressure, but the reduction was Pmax and Tmax will reflect the combustion of both thepremixed burning phase and the subsequently diffusivefound to be insensitive to the proportion of oxygen

within the 6–11 per cent range of testing, and the burning phase. Two factors are considered to affect the

Fig. 10 Calculated maximum mean gas temperature of the fuel blends



value of Tmax : one is the heat of evaporation and CV

in the diffusive burning phase due to oxygen enrich-ment favours an increase in Tmax and comprehensiveand the other is the predicted combustion improvement

of the diffusive burning phase. With respect to the effectiveness shows little influence of methanol additionon Tmax for the diesel/methanol blends.influence of the diffusive burning phase on Tmax , the

calculation based on the thermodynamic model revealed Figures 11 and 12 give the maximum rate of pressurerise (dp/dQ)max and the maximum rate of heat releasethat the peak mean gas temperature Tmax occurs at about

10° CA later than that of the peak cylinder pressure, (dQB /dQ)max at three settings of the fuel delivery advanceangle. It was found that the curves of (dp/dQ)max andwhich indicated that Tmax occurred within the diffusive

combustion period. Thus, it can be suggested that Tmax (dQB/dQ)max demonstrate similar patterns, which revealedthat the term dp/dQ would play a decisive role inwould be influenced to some degree by the diffusive

combustion process and combustion improvement of determining dQB /dQ in the fast burning period and isless dependent on the terms dV/dQ and dC

V/dQ. At a lowthe diffusive burning phase would influence Tmax . An

increase in the methanol mass fraction will increase the engine speed (1500 r/min), (dQB /dQ)max and (dp/dQ)maxincrease with the increase in the methanol mass fractionheat of evaporation and C

V, which may lead to a

decrease in Tmax . However, combustion improvement and the behaviour is more obvious at high engine load.

Fig. 11 Maximum rate of pressure rise of the fuel blends



Fig. 12 Maximum heat release rate of the fuel blends

The increase in the ignition delay with the increase in 4 CONCLUSIONSthe methanol mass fraction would make more fuel tobe burned in the premixed burning phase and increase A stabilized diesel/methanol blend was developed and(dQB /dQ)max and (dp/dQ)max . However, at a high engine a combustion and heat release analysis was carried outspeed (2000 r/min), (dQB /dQ)max and (dp/dQ)max show in a compression ignition engine. The main results area relatively high increasing trend with the increase summarized as follows:in the methanol mass fraction at high engine load

1. Increasing the methanol mass fraction of the diesel/(b.m.e.p.=0.608 MPa), a relatively low increasing trendmethanol blends will result in an increase in the heatwith the increase in the methanol mass fraction atrelease rate in the premixed burning phase and shortenmiddle engine load (b.m.e.p.=0.392 MPa) and a slightthe combustion duration of the diffusive burning phase.decreasing trend with the increase in the oxygen mass

2. The ignition delay increases with the increase in thefraction at low engine load (b.m.e.p.=0.208 MPa). Lowmethanol mass fraction, with the behaviour beingvalues of (dp/dQ)max and (dQB /dQ)max for diesel/methanolmore obvious at low engine load and high engineblends at low engine load and high engine speed would

be due to the extension of combustion. speed. The rapid burn duration varies little with the



6 Huang, Z. H., Wang, H. W. and Chen, H. Y. Study onmethanol mass fraction and the total combustioncombustion characteristics of a compression ignition engineduration decreases with the increase in the methanolfueled with dimethyl ether. Proc. Instn Mech. Engrs, Part D:mass fraction.J. Automobile Engineering, 1999, 213(D6), 647–652.3. At a low engine speed, the centre of the heat release

7 Kajitani, Z., Chen, L. and Konno, M. Engine performancecurve is close to TDC, the maximum rate of pressureand exhaust characteristics of direct-injection diesel engine

rises and the heat release rate increases with the operated with DME. SAE Trans., 1997, 106(4), 1568–1577.increase in the methanol mass fraction. At a high 8 Huang, Z., Miao, H., Zhou, L. and Jiang, D. Combustionengine speed and load, the centre of the heat release characteristics and hydrocarbon emissions of a spark ignitioncurve is also close to TDC while it departs from TDC engine fuelled with gasoline-oxygenate blends. Proc. Instnat low engine load. Mech. Engrs, Part D: J. Automobile Engineering, 2000,

214(D3), 341–346.4. The peak cylinder gas pressure increases with the9 Huang, Z. H., Jiang, D. M., Zeng, K., Liu, B. andincrease in the methanol mass fraction and the pre-

Yang, Z. L. Combustion characteristics and heat releasesence of oxygen reduces the peak pressure, but theanalysis of a DI compression ignition engine fueled withreduction was found to be insensitive to the proportiondiesel–dimethyl carbonate blends. Proc. Instn Mech.of oxygen within the 6–11 per cent range of testing.Engrs, Part D: J. Automobile Engineering, 2003, 217(D7),595–606.

10 Wang, H. W., Huang, Z. H., Zhou, L. B., Jiang, D. M. andACKNOWLEDGEMENTS Yang, Z. L. Investigation on emission characteristics of a

compression ignition engine with oxygenated fuels andThis study was supported by the National Science exhaust gas recirculation. Proc. Instn Mech. Engrs, Part D:Fund for Distinguished Young Scholars from the J. Automobile Engineering, 2000, 214(D5), 503–508.

11 Murayama, T., Zheng, M. and Chikahisa, T. SimultaneousNational Natural Science Foundation of China (grantreduction of smoke and NO

xfrom a DI diesel engine with59925617), the Ford–China Research and Develop-

EGR and dimethyl carbonate. SAE paper 952518, 1995.ment Fund (50122166), the National Basic Research12 Ajav, E. A., Singh, B. and Bhattacharya, T. K. ExperimentalProgram (2001CB209208) and the Key Project of the

study of some performance parameters of a constant speedNational Natural Science Fund (50136040). The authorsstationary diesel engine using ethanol–diesel blend as fuel.acknowledge the students of Xi’an Jiaotong UniversityBiomass and Bioenergy, 1999, 17, 357–365.

for their help with the experiment. The authors also 13 Bertoii, C., Giacomo, N. D. and Beatrice, C. Diesel com-express their thanks to their colleagues at Xi’an Jiaotong bustion improvements by the use of oxygenated syntheticUniversity for their helpful comments and advice during fuels. SAE Trans., 1997, 106(4), 1557–1567.the preparation of the manuscript. 14 Miyamoto, N., Ogawa, H. and Obata, K. Improvements of

diesel combustion and emissions by addition of oxygenatedagents to diesel fuels: influence of properties of diesel fuelsand kinds of oxygenated agents. JSAE Rev., 1998, 19(2),REFERENCES154–156.

15 Akasaka, Y. and Sakurai, Y. Effect of oxygenated fuel on1 Huang, Z., Shiga, S., Ueda, T., Nakamura, H., Ishima, T.,exhaust emission from DI diesel engines. Trans. Jap. Soc.Obokata, T., Tsue, M. and Kono, M. Effect of fuel injectionMech. Engrs, 1996, Ser. B, 63(609), 1833–1839.timing relative to ignition timing on the natural-gas direct-

16 Satge de Caro, P., Mouloungui, E., Vaitilingom, G. andinjection combustion. Trans. ASME, J. Engng for GasBerge, J. C. Interest of combining an additive with diesel–Turbines and Power, 2003, 125(3), 783–790.ethanol blends for use in diesel engines. Fuel, 2001, 80,2 Shiga, S., Ozone, S., Machacon, H. T. C., Karasawa, T.,565–574.Nakamura, H., Ueda, T., Jingu, N., Huang, Z., Tsue, M.

17 Ali, Y., Hanna, M. A. and Borg, J. E. Optimization ofand Kono, M. A study of the combustion and emissiondiesel, methyl tallowate and ethanol blend for reducingcharacteristics of compressed-natural-gas direct-injectionemissions from diesel engine. Bioresource Technol., 1995,stratified combustion using a rapid-compression-machine.52, 237–243.Combust. Flame, 2002, 129(1–2), 1–10.

18 He, X., Zan, Y. and Li, S. Fuels for Internal Combustion3 Fleisch, T., McCarthy, C. and Basu, A. A new clean dieselEngines, 1999 (Chinese Petroleum and Chemical Press,technology: demonstration of ULEV emissions on a NavistarBeijing, PR China).diesel engine fueled with dimethyl ether. SAE Trans., 1995,

19 Huang, Z. H., Shiga, S., Ueda, T., Jingu, N., Nakamura, H.,104(4), 42–53.Ishima, T., Obokata, T., Tsue, M. and Kono, M. A basic4 Kapus, P. and Ofner, H. Development of fuel injectionbehavior of CNG DI combustion in a spark-ignited rapidequipment and combustion system for DI diesels operatedcompression machine. Jap. Soc. Mech. Engrs Int. J. Ser. B,on dimethyl ether. SAE Trans., 1995, 104(4), 54–69.Fluids and Thermal Engng, 2002, 45(4), 891–900.5 Sorenson, S. C. and Mikkelsen, S. E. Performance and

20 Heywood, J. B. Internal Combustion Engine Fundamentals,emissions of a 0.273 liter direct injection diesel engine fueled1988 (McGraw-Hill, New York).with neat dimethyl ether. SAE Trans., 1995, 104(4), 80–90.


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A B A blend Bgr.xjtu.edu.cn/upload/PUB.1643.4/Combustion... · diameters smaller than 10 and 2.5 m m respectively). practical measures for the improvement of combustion Almost all