A simple two-zone mass transfer model was used to predict the mean squish velocity history at the rim of a conventional bowl-in-piston combustion chamber. The chamber’s geometry produces gas flow that converges radially inwards (“squish”) as TDC (top dead center) is approached. The squish flow generates turbulence, which can be used to enhance the combustion rate. When compared with PIV (particle image velocimetry) measurements, the peak squish velocity at the bowl rim was 12% less than the value predicted by the simple mass transfer model. After a thorough examination, the assumption of uniform density in the simple model was strongly suspected to be the cause of this discrepancy. Improvements were made to the simple model to account for density variations that are caused by nonuniform heat transfer in the combustion chamber. The revised model yielded velocities that were in close agreement with PIV measurements.

1.
Fansler
,
T. D.
, and
French
,
D. T.
, 1987, “
Swirl, Squish and Turbulence in Stratified-Charge Engines: Laser Velocimetry Measurements and Implications for Combustion
,” SAE Paper No. 870371.
2.
Monaghan
,
M. L.
, and
Pettifer
,
H. F.
, 1981, “
Air Motion and Its Effects on Diesel Performance and Emissions
,” SAE Paper No. 810255.
3.
Bacon
,
D. M.
,
Renshaw
,
J.
, and
Walker
,
K. L.
, 1981, “
The Use of In-Cylinder Modelling and LDA Techniques in Diesel Engine Design
,”
Proceedings of the International Conference on New Energy Conservation Technologies and their Commercialization
,
J. P.
Milhone
and
E. H.
Willis
, eds.,
Springer-Verlag
, Berlin, pp.
2431
2440
.
4.
Johns
,
R. J. R.
, 1985, “
The Effect of Piston Bowl Offset on the Compression-Induced Air Motion in Direct Injection Diesel Engine Combustion Chambers
,”
Proceedings of the International Symposium on Diagnostics and Modeling of Combustion in Reciprocating Engines
, Tokyo, pp.
489
502
.
5.
Döhring
,
K.
, 1986, “
The Relative Effects of Intake and Compression Generated Turbulence on I.C. Engine Combustion Duration
,” M.A.Sc. thesis, University of British Columbia.
6.
Lappas
,
P.
, 2003, “
An Experimental and Computational Study of Flow in the Squish Jet Combustion Chamber
,” Ph.D. thesis, University of British Columbia.
7.
Heywood
,
J. B.
, 1988,
Internal Combustion Engine Fundamentals
,
McGraw-Hill
, New York, pp.
353
357
.
8.
Tabaczynski
,
R. J.
, 1976, “
Turbulence and Turbulent Combustion in Spark-Ignition Engines
,”
Prog. Energy Combust. Sci.
0360-1285,
2
, pp.
143
165
.
9.
Anetor
,
L.
, 1994, “
Experimental and Numerical Simulation of Charge Motion in Internal Combustion Engines
,” Ph.D. thesis, University of British Columbia.
10.
Melling
,
A.
, 1997, “
Tracer Particles and Seeding for Particle Image Velocimetry
,”
Meas. Sci. Technol.
0957-0233,
8
(
12
), pp.
1406
1416
.
11.
Keane
,
R. D.
, and
Adrian
,
R. J.
, 1992, “
Theory of Cross-Correlation Analysis of PIV Images
,”
Appl. Sci. Res.
0003-6994,
49
, pp.
191
215
.
12.
Bhattacharyya
,
G. K.
, and
Johnson
,
R. A.
, 1977,
Statistical Concepts and Methods
,
John Wiley and Sons
, New York, Chap. 8
13.
Annand
,
W. J. D.
, 1963, “
Heat Transfer in the Cylinders of Reciprocating Internal Combustion Engines
,”
Proc. Inst. Mech. Eng.
0020-3483,
177
(
36
), pp.
973
990
.
14.
Alkidas
,
A. C.
, 1980, “
Heat Transfer Characteristics of a Spark-Ignition Engine
,”
ASME J. Heat Transfer
0022-1481,
102
, pp.
189
193
.
15.
Maciejewski
,
P. K.
, and
Moffat
,
R. J.
, 1992, “
Heat Transfer with Very High Free-Stream Turbulence: Part II—Analysis of Results
,”
ASME J. Heat Transfer
0022-1481,
114
(
4
), pp.
834
839
.
You do not currently have access to this content.