This paper describes an attempt to separate out and to quantify the relative importance of fuel injection characteristics and in-cylinder air motion as factors influencing the rate of fuel-air mixing and of combustion in high-speed D.I. diesel engines, where bulk swirling air motion is absent. Tests on a 121 mm bore × 139 mm stroke, 1.6 liter, single-cylinder engine at constant engine speed reveal substantially shorter fuel-air mixing times as the mean fuel injection kinetic energy (M.I.K.E.) is increased. Also, tests at constant injection kinetic energy but with varying engine speed (involving different fuel injection system builds at each speed) show that fuel-air mixing times are reduced at higher engine speeds. From these trends it is concluded that, while injection kinetic energy is the dominant factor in determining fuel-air mixing rates in D.I. diesels, small-scale turbulent air motions, the intensity and structure of which are related to engine speed, also exert an important influence on the mixing rate.

Issue Section:
Internal Combustion Engines
Topics:
Diesel engines, Engines, Fuels, Kinetic energy, Sprays, Combustion, Cylinders, Single-cylinder engines, Swirling flow, Turbulence
1.
Arcoumanis, C., and Whitelaw, J. H., 1987, “Fluid Mechanics of Internal Combustion-Engines—a Review,” Proc. Inst. Mech. Engrs., Vol. 201, No. C1.
2.
Ball
 
W. F.
,
1981
, “
Einflusse des Einspritzdruckes auf die Verbrennung bei Dieselmotoren mit Direkteinspritzung ohne Luftdroll
,”
MTZ
, Vol.
42
, No.
4
, pp.
141
–
149
.
3.
Ball, W. F., and Timoney, D. J., 1981, “The Performance of a Quiescent Direct Injection Diesel Combustion System and Its Comparison With Prediction,” Presented at CIMAC, Helsinki, 8–12 June.
4.
Bazari, Z., 1992, “A DI Diesel Combustion and Emissions Predictive Capability for Use in Cycle Simulation,” SAE Paper No. 920462.
5.
Beck et al., 1988, “Effects of Fuel Injection on Diesel Combustion,” SAE Paper No. 880299.
6.
Catania, A. E., et al., 1992, “Time-Frequency Spectral Structure of Turbulence in an Automotive Engine,” SAE Paper No. 920153.
7.
Catania
 
A. E.
, and
Mittica
 
A.
,
1987
, “
Induction System Effects on Small-Scale Turbulence in a High-Speed Diesel Engine
,”
ASME JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER
, Vol.
112
, pp.
357
–
368
.
8.
Catania
 
A. E.
, and
Mittica
 
A.
,
1990
, “
Autocorrelation and Autospectra Estimation of Reciprocating Engine Turbulence
,”
ASME JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER
, Vol.
112
, pp.
357
–
368
.
9.
Chikahisa et al., 1992, “Combustion Similarity for Different Size Diesel Engines: Theoretical Prediction and Experimental Results,” SAE Paper No. 920465.
10.
Doyle et al., 1989, “Application of an Advanced In-Line Injection System to a Heavy Duty Diesel Engine,” SAE Paper No. 891847.
11.
Herzog, P., 1989, “The Ideal Rate of Injection for Swirl Supported Diesel Engines,” Presented at IMechE Seminar on Diesel Fuel Injection Systems, London, 10–11 Oct.
12.
Heywood
 
J. B.
,
1986
, “
Fluid Motion Within The Cylinder of Internal Combustion Engines—The 1986 Freeman Scholar Lecture
,”
ASME Journal of Fluids Engineering
, Vol.
109
, pp.
3
–
35
.
13.
Ikegami et al., 1988, “Diesel Combustion and the Pollutant Formation as Viewed From Turbulent Mixing Concept,” SAE Paper No. 880425.
14.
Ikegami et al., 1990, “Combustion Chamber Shape and Pressurised Injection in High-Speed Direct Injection Diesel Engines,” SAE Paper No. 900440.
15.
Kamimoto
 
T.
, and
Kobayashi
 
H.
,
1991
, “
Combustion Processes in Diesel Engines
,”
Prog. Energy Combust. Sci.
, Vol.
17
, pp.
163
–
189
.
16.
Konno et al., 1992, “Reduction of Smoke and NOx by Strong Turbulence Generated During the Combustion Process in D.I. Diesel Engines,” SAE Paper No. 920467.
17.
Krieger, K., 1989, “Diesel Fuel Injection Systems for Heavy Duty Engines,” Presented at IMechE Seminar on Diesel Fuel Injection Systems, London, 10–11 Oct.
18.
Lancaster, D. R., et al., 1976, “Effects of Turbulence on Spark-Ignition Engine Combustion,” SAE Paper No. 760160.
19.
Lancaster, D. R., 1976, “Effects on Engine Variables on Turbulence in a Spark-Ignition Engine,” SAE Paper No. 760159.
20.
Magnussen, B. F., and Hjertager, B. H., 1976, “On Mathematical Modelling of Turbulent Combustion With Special Emphasis on Soot Formation and Combustion,” 16th Symposium (International) on Combustion, The Combustion Institute.
21.
Nagano et al., 1994, “Reduction of Exhaust Emissions by Air-Jet Turbulence in a DI Diesel Engine: Application to an In-Line 6-Cylinder Engine,” JSAE Review 15, pp. 9–14.
22.
Nakakita
 et al.,
1991
, “
Effects of High Pressure Fuel Injection on the Combustion and Exhaust Emissions of a High-Speed Diesel Engine
,”
JSAE Review
, Vol.
12
, No.
1
, pp.
18
–
25
, Jan.
23.
Needham, J. R., et al., 1990, “Injection Timing and Rate Control—A Solution for Low Emissions,” SAE Paper No. 900854.
24.
Needham
 
J. R.
, and
Whelan
 
S.
,
1994
, “
Meeting the Challenge of Low Emissions and Fuel Economy With the Ricardo Four-Valve High-Speed Direct Injection Engine
,”
Proc. Instn. Mech. Engnrs Part D
, Vol.
208
, pp.
181
–
190
.
25.
Plee, S. L., and Ahmad, T., 1983, “Relative Roles of Premixed and Diffusion Burning in Diesel Combustion,” SAE Paper No. 831733.
26.
Ramos, J. I., 1989, Internal Combustion Engine Modelling, Hemisphere Publishing Corporation.
27.
Russell et al., 1989, “Rate Modulation for Direct Injection Diesel Engines,” Presented at IMechE Seminar on Diesel Fuel Injection Systems, London, 10–11 Oct.
28.
Sakata et al., 1990, “Development of Toyota Reflex Burn (TRB) System in DI Diesel,” SAE Paper No. 900658.
29.
Smith, W. J., and Timoney, D. J., 1991, “Fuel Injection Rate Analysis Using Measured Data,” IMechE Paper C430/057, IMechE Proceedings Computers in Engine Technology.
30.
Smith, W. J., and Timoney, D. J., 1992, “Fuel Injection Rate Analysis—A New Diagnostic Tool for Combustion Research,” SAE Paper No. 922224.
31.
Timoney, D. J., 1985a, “Engine Speed-Related Effects in D.I. Diesel Combustion,” Presented at the International Symposium on Advanced Engine Research (ISER), University of Wisconsin, Madison, U.S.A., Sept.
32.
Timoney, D. J., 1985b, “Smoke and Fuel Consumption Measurements in a Direct Injection Diesel Engine With Variable Swirl,” SAE Paper No. 851542.
33.
Timoney, D. J., 1987a, “Effects of Important Variables on Measured Heat Release Rates in a D.I. Diesel,” SAE Paper No. 870271.
34.
Timoney, D. J., 1987b, “Problems With Heat Release Analysis in D.I. Diesels,” SAE Paper No. 870270.
35.
Timoney, D. J., 1987c, “Energetics of Fuel-Air Mixing in D.I. Diesel Engines,” Proc. International Centre for Heat and Mass Transfer, 26, D. Brian Spalding and N. H., Afgan, ed., Hemisphere Publishing Corporation, pp. 189–199.
36.
Timoney, D. J., and Smith, W. J., 1987, “Influence of Turbulence in a D.I. Diesel,” Proc. NATO Advanced Study Institute on Combusting Flow Diagnostics, Montechoro, Portugal, Apr.
37.
Timoney, D. J., and Smith, W. J., 1993, “Relationships Between Instantaneous Fuel Injection Rate and Exhaust Emissions From a D.I. Diesel Combustion System,” 20e Conseil International des Machines a Combustion (CIMAC-20), London, May, Paper D80.
38.
Tippelman, G., 1977, “A New Method of Investigation of Swirl Ports,” SAE Paper No. 770404.
39.
Witze, P. O., 1977, “Measurement of the Spatial Distribution and Engine Speed Dependence of Turbulent Air Motion in an I.C. Engine,” SAE Paper No. 770220.
40.
Zelenka et al., 1990, “Ways Towards the Clean Heavy Duty Diesel,” SAE Paper No. 900602.
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