Design and Simulation of Two Stroke Engines

Roots blower
in turbocharged/supercharged fuel-injected engine,
13-14, 15
Saab vehicles
and Monte Carlo Rally, 2
S AE (Society of Automotive Engineers)
Standard J604D, 27
Sako/Nakayama experimental data (178 cc snowmobile
engine)
NO emissions, 478-479
Sato, T.
liquid gasoline injection studies, 513-514
Scavenge ratio (SR)
defined, 27, 212
Scavenging
definitions
purity (idealized incoming scavenge flow),
212
scavenge ratio, 27, 212
scavenging efficiency (basic), 28, 212-213
scavenging efficiency (perfect displacement),
213-214
scavenging efficiency (perfect mixing),
214-215
scavenging purity, 28
fundamental theory of, 211-213
see also isothermal scavenge model (below)
Benson-Brandham model
comparison with QUB test results, 233-236
loop/cross/uniflow scavenging, relevance of
model to, 218-219
predictive value, inadequacy of, 233
purity, importance of (and SE curve), 217-218
trapping characteristics model, advantages of,
216-218
two part (mixing/displacement) model,
215-217
Yamaha DT250 cylinders: QUB test results
vs. Benson-Brandham models, 234-235
see also Computer modeling (various)
blower scavenging (three-cylinder supercharged
engine)
exhaust tuning, 405-407
open-cycle pressures and charging (cylinders
1-2), 404-405
615
Index
temperature and purity in scavenging ports,
405, 406
blower scavenging (four-cylinder supercharged
engine)
introduction and discussion, 407
four cylinders, advantages of, 409
open port period, three cylinder vs. four cylinder,
409
open-cycle pressures and charging (cylinders
1-2), 407-409
CFD (Computational Fluid Dynamics) in
introduction, 244
Ahmadi-Befrui predictive calculations, 250
charge purity plots (Yamaha test cylinders),
246-248
in future design and development (discussion),
274, 275-276
grid structure for scavenging calculations,
244-245
PHOENICS CFD port design code, flow assumptions
in, 245-246
as a port design tool (loop scavenging),
264-265
SE-TE-SR plots (CFD vs. experimental values),
248-250
cross scavenging
Clerk, Sir Dugald (deflector piston), 9, 10
combustion chamber design for, 339
design advantages of, 253-254
detonation/preignition potential of, 10
ease of optimization, 253
influence on SE-SR and TE-SR characteristics,
218-219
manufacturing advantages of, 10-11
piston for (conventional), 10, 11
piston for (QUB type), 10, 11, 12
port design for. See Port design, scavenging
scavenging efficiency of, 10, 11
design and development techniques (discussion)
CAD/CAM techniques, 274, 275
CFD, use of, 274, 275-276
experimental experience, summary of,
273-274
rapid prototyping (stereo lithography), 274,
276
see also Computer modeling (various)
effect on exhaust emissions, 484-486