Design and Simulation of Two Stroke Engines

Design and Simulation of Two-Stroke Engines
DKW machines
early supercharged models, 1
Duret, P.
Institut Francais du Petrole stratified charging
engine, 504
Dynamometer testing. See Performance measurement
Efficiency
mechanical (defined), 37-38
see also Friction/friction losses
Eight-stroking
from inadequate scavenging, 218
Empirical design assistance
introduction, 415-416
disc valve design. See under Disc valves
engine porting
chainsaw performance, effect of porting
changes on, 426-431
determination of Asv (measured), 424-426
engine performance values vs. Asv (QUB experience),
420-423
mass flow rates, 417-419
port area vs. crankshaft angle, 417
specific time area (Asv), derivation of,
419-420
TTMEAREA TARGETS program, derived
Asv values from, 423-424
see also practical considerations (below);
Specific time area (Asv)
exhaust systems
tuned (high-performance engine), 437-445
untuned, 435-437
see also Exhaust systems
practical considerations
introduction, 431
basic engine dimensions, acquisition of,
431-432
data selection, remarks on, 445-446
empiricism in general (comment), 434-435
exhaust ports, width criteria for, 432
factors driving a new design, 431
inlet ports, width criteria for, 433
port timing criteria, 434
scavenge port layout (piston ported engine),
433
transfer ports, width criteria for, 433-434
598
unpegged rings, 433-434
reed valve design. See under Reed valves
Engine testing. See Performance measurement
Equivalence ratio
defined, 299
in compression-ignition engines, 305
in lean mixture combustion, 300
in rich mixture combustion, 299
in SI engines, 304-305
see also Air-fuel ratio
Exhaust closure. See Port design; Port timing;
Trapping
Exhaust emissions/exhaust gas analysis
air-fuel ratio (general)
importance of (discussion), 465
molecular, 297-298
stoichiometric, 298-299
air-fuel ratio, effect of (low emissions engine)
bsCO emissions, 488
bsHC emissions, 487-488
bsC>2 emissions, 487-488
air-fuel ratio, effect of (QUB 400 research engine)
bsHC emissions, 473-476
CO emissions, 473-475
G-> emissions, 473, 475
air-i uel ratio, effect of (two-zone chainsaw engine
simulation)
brake specific hydrocarbon emissions,
479-480, 482
on bsCO emissions, 480-482
CO2 mass ratio, 353, 354-355
on CO mass ratio, 352, 354
cylinder temperature (vs. crankshaft angle),
349-350
hydrogen mass ratio, 354, 355
NO growth rate, 349-352
peak temperatures (burn/unburned zones),
349,350
Batoni performance maps (Vespa motor scooter
engine)
CO emissions, 476-478
HC emissions, 478
butterfly exhaust valve, effect of (HC emissions),
491-492, 493
carbon dioxide (CO2)
two-zone closed cycle combustion model
(chainsaw), 353, 354-355
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