50:
153:
135:, which processes the signal to determine if, in fact, knock is occurring. If it is, then the control unit activates a solenoid valve that directs boost pressure to the turbocharger's pneumatically controlled wastegate, that opens to bypass exhaust gases from the turbocharger directly to the exhaust pipe, lowering turbo
143:
may be connected. This LED will then light up if knock is detected. Because the knock sensor becomes less accurate at high revolutions, the APC tapers maximum boost pressure after approximately 4,500 RPM.
179:
in the instrument panel. Although knock sensors are common even on non-turbocharged and turbocharged engines today, Saab has continued to use the APC name prominently as a differentiating feature.
42:
in 1982, and the APC was fitted to all subsequent 900 Turbos through 1993 (and 1994 convertibles), as well as 9000 Turbos through 1989. The APC was sold to
Maserati to equip the carbureted
139:
pressure until the knock subsides. Knock events that are managed by the APC can be discerned when the in-dash boost needle "twitches" slightly. The APC unit has a 'knock' output where an
109:, and uses these inputs to control a solenoid valve that trims the rate of rise of pressure as well as the maximum pressure by directing boost pressure to the turbocharger's pneumatic
278:
91:
The APC controls boost pressure and the overall performance, specifically the rate of rise and maximum boost level - and it detects and manages harmful knock events.
271:
846:
131:) bolted to the engine block responds to unique frequencies caused by engine knock. The sensor generates a small voltage that is sent to the
186:
under normal driving conditions, the short white dash is atmospheric pressure (engine off), the orange scale is where there is safe turbo
205:/APC system, available in 9000 models only. The DI/APC system managed knock not only by decreasing boost via a solenoid but by retarding
264:
785:
463:
187:
760:
344:
77:
935:
287:
896:
810:
755:
707:
615:
201:
Saab integrated the APC's boost control functionality with ignition control in 1990 with the introduction of the
891:
732:
441:
218:
46:, with different settings for the Biturbo, and was known as the Maserati Automatic Boost Controller (MABC).
666:
132:
76:(initially, 8.5:1 as opposed to 7.2:1, and, on 16-valve variants introduced in 1985, 9.0:1). This improved
488:
95:
605:
446:
243:
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372:
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750:
648:
378:
671:
468:
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73:
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43:
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393:
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183:
85:
742:
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567:
334:
99:
940:
929:
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798:
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620:
552:
547:
511:
428:
368:
329:
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120:
39:
36:
24:
531:
526:
493:
398:
388:
324:
308:
136:
909:
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562:
521:
478:
408:
202:
157:
23:) was the first engine knock and boost control system. The APC was invented by
881:
841:
820:
815:
717:
702:
625:
557:
483:
423:
354:
191:
175:) models with this unit include the APC name displayed on a non-numeric boost
128:
106:
29:
256:
836:
577:
572:
359:
339:
110:
152:
859:
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727:
458:
383:
349:
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102:
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223:
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403:
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81:
49:
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48:
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as well; DI/APC also managed the engine's basic ignition timing.
851:
260:
298:
140:
94:
To control the turbocharger, the APC monitors the engine's
869:
829:
784:
741:
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657:
639:
586:
540:
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422:
307:
182:The white area on the left side of the scale shows
272:
8:
279:
265:
257:
190:, the red scale is boost above 0.5 - 0.7
345:Crankcase ventilation system (PCV valve)
84:without causing engine damage caused by
234:
194:where the wastegate may be opened or a
7:
14:
447:Overhead valve (pushrod) layout
27:at the Swedish car maker SAAB.
1:
17:Automatic Performance Control
198:due to overboost may occur.
244:"Turbocharger with a brain"
242:Jack, Keebler (July 1982).
35:SAAB introduced it on the
957:
288:Internal combustion engine
905:
756:Diesel particulate filter
708:Idle air control actuator
649:Engine control unit (ECU)
294:
72:The APC allowed a higher
821:Viscous fan (fan clutch)
733:Throttle position sensor
442:Overhead camshaft layout
219:Saab Information Display
360:Core plug (freeze plug)
133:electronic control unit
80:and allowed the use of
164:
69:
155:
52:
30:U.S. patent 4,372,119
601:Compression ignition
751:Catalytic converter
169:Full Pressure Turbo
119:To detect knock, a
59:pressure transducer
877:Knocking / pinging
469:Combustion chamber
165:
70:
936:Engine technology
923:
922:
892:Stratified charge
659:Electrical system
641:Engine management
474:Compression ratio
414:Starter ring gear
313:rotating assembly
82:low-octane petrol
74:compression ratio
948:
766:Exhaust manifold
631:Spark plug wires
517:Boost controller
504:Forced induction
281:
274:
267:
258:
252:
251:
250:. July 1982: 85.
239:
44:Maserati Biturbo
32:
956:
955:
951:
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949:
947:
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926:
925:
924:
919:
901:
897:Top dead centre
865:
825:
780:
737:
686:
660:
653:
642:
635:
582:
536:
498:
454:Tappet / lifter
437:Flathead layout
427:
418:
312:
303:
290:
285:
255:
248:Popular Science
241:
240:
236:
232:
215:
207:ignition timing
184:manifold vacuum
150:
148:APC boost gauge
105:via a pressure
68:
28:
12:
11:
5:
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788:
786:Cooling system
782:
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753:
747:
745:
743:Exhaust system
739:
738:
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735:
730:
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715:
713:Inlet manifold
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568:Fuel injection
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335:Connecting rod
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177:pressure gauge
149:
146:
100:inlet manifold
67:
66:
65:solenoid valve
63:
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57:
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40:Saab H engines
13:
10:
9:
6:
4:
3:
2:
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799:Water cooling
797:
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776:Oxygen sensor
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691:Intake system
689:
683:
682:Starter motor
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664:
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621:Ignition coil
619:
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553:Petrol engine
551:
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548:Diesel engine
546:
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528:
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518:
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512:Blowoff valve
510:
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429:Cylinder head
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348:
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328:
326:
323:
321:
320:Balance shaft
318:
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315:
310:
306:
302:
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293:
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130:
127:(basically a
126:
122:
121:piezoelectric
117:
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108:
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97:
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87:
83:
79:
75:
64:
61:
58:
55:
54:
51:
47:
45:
41:
38:
37:turbo charged
33:
31:
26:
25:Per Gillbrand
22:
18:
806:Electric fan
606:Coil-on-plug
532:Turbocharger
527:Supercharger
399:Main bearing
389:Firing order
379:Displacement
325:Block heater
309:Engine block
297:Part of the
296:
247:
237:
200:
181:
172:
168:
166:
118:
93:
90:
78:fuel economy
71:
62:control unit
56:knock sensor
34:
20:
16:
15:
830:Lubrication
794:Air cooling
611:Distributor
563:Fuel filter
541:Fuel system
522:Intercooler
489:Timing belt
479:Head gasket
409:Piston ring
158:boost gauge
930:Categories
882:Power band
842:Oil filter
816:Thermostat
761:EGT sensor
723:MAF sensor
718:MAP sensor
703:Air filter
667:Alternator
626:Spark plug
558:Carburetor
484:Rocker arm
424:Valvetrain
355:Crankshaft
299:Automobile
230:References
156:turbo/APC
129:microphone
107:transducer
616:Glow plug
578:Fuel tank
573:Fuel pump
340:Crankcase
111:wastegate
915:Category
860:Dry sump
856:Wet sump
847:Oil pump
811:Radiator
728:Throttle
588:Ignition
459:Camshaft
384:Flywheel
365:Cylinder
350:Crankpin
213:See also
196:fuel cut
162:Saab 900
114:actuator
103:pressure
887:Redline
771:Muffler
672:Battery
596:Magneto
224:Trionic
910:Portal
698:Airbox
677:Dynamo
404:Piston
394:Stroke
373:layout
301:series
125:sensor
123:knock
870:Other
494:Valve
464:Chest
188:boost
167:Saab
160:in a
137:boost
86:knock
941:Saab
852:Sump
369:bank
330:Bore
98:and
837:Oil
426:and
311:and
192:bar
173:FPT
141:LED
96:RPM
21:APC
932::
858:,
371:,
246:.
203:DI
116:.
88:.
862:)
854:(
375:)
367:(
280:e
273:t
266:v
171:(
19:(
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