524:
112:
123:
532:
277:
31:
154:, several cars and motorcycles used inlet valve(s) located in the cylinder head, however these valves were vacuum-actuated ("atmospheric") rather than driven by a camshaft as with typical OHV engines. The exhaust valve(s) were driven by a camshaft, but were located in the engine block as with side-valve engines.
252:
pushrod engine. Due to a loophole in the rules, the pushrod engine was allowed to use a larger displacement and higher boost pressure, significantly increasing its power output compared to the OHC engines used by other teams. Team Penske qualified in pole position and won the race by a large margin.
345:
The lubrication requirements for OHV cylinder heads are much lower, as they typically have a single camshaft within the block, where an OHC engine can have two per bank of cylinders, requiring oil passages through the cylinder head. OHV heads only need lubrication for the rocker arms at the pushrod
375:
In OHV engines, the size and shape of the intake ports as well as the position of the valves are limited by the pushrods and the need to accommodate them in the head casting. As a result, it is rare for an OHV engine to have more than two valves per cylinder, while OHC engines often have four,
241:; however, use of this design was mostly limited to high-performance cars for many decades. OHC engines slowly became more common from the 1950s to the 1990s, and by the start of the 21st century, the majority of automotive engines (except for some North American V8 engines) used an OHC design.
304:
A V-type engine design allows both cylinder heads to be mirror images of each other at the front of each cylinder bank. In a V-type OHV engine design, it is possible to use the same cylinder head casting for both banks, by simply flipping it around for the second bank. The
339:, which add complexity. In contrast, an OHV engine has the camshaft positioned close to the crankshaft, which may be driven by a much shorter chain or even direct gear connection. However, this is somewhat negated by a more complex valvetrain requiring pushrods.
193:) from 1899–1902, where the overhead valve engine design was further refined. This engine employed pushrod-actuated rocker arms, which in turn opened poppet valves parallel to the pistons. Marr returned to Buick in 1904 (having built a small quantity of the
350:, and rocker tip. This lubrication is typically provided through the hollow pushrods themselves rather than a dedicated lubrication system in the head. The reduced lubrication requirements can also mean that a smaller, lower-capacity oil pump is used.
80:(OHC) engine also has overhead valves, the common usage of the term "overhead valve engine" is limited to engines where the camshaft is located in the engine block. In these traditional OHV engines, the motion of the camshaft is transferred using
197:, with one of the first known engines to use an overhead camshaft design), the same year that Buick received a patent for an overhead valve engine design. In 1904, the world's first production OHV engine was released in the
173:, therefore becoming the first OHV engines. In 1896, U.S. patent 563,140 was taken out by William F. Davis for an OHV engine with liquid coolant used to cool the cylinder head, but no working model was built.
205:
design with two valves per cylinder. The engine was very successful for Buick, with the company selling 750 such cars in 1905, and the OHV engine has powered almost all Buick automobiles since then.
298:
design of an OHV engine results in a smaller overall size, compared with an equivalent OHC engine, which can have some advantages in center of gravity and hood height in V-engine designs.
590:
797:
1454:
88:
to operate the valves at the top of the engine. However, some designs have the camshaft in the cylinder head but still sit below or alongside the valves (the
732:
306:
1459:
790:
693:
1365:
503:
483:
458:
594:
783:
1304:
223:"side-valve" engines remained commonplace in the U.S. until the mid-to-late 1950s, when they began to be phased out for OHV engines.
656:
622:
580:
Hobbs, Leonard S. The Wright
Brothers' Engines and Their design. Washington, D.C.: Smithsonian Institution Press, 1971, p 61, 63.
476:
Theorie und
Konstruktion eines rationellen Wärmemotors zum Ersatz der Dampfmaschinen und der heute bekannten Verbrennungsmotoren
982:
722:
1279:
398:
143:, which was first successfully run in 1876. As internal combustion engines began to develop separately to steam engines,
1469:
863:
1464:
365:(i.e., the lifters, pushrods, and rockers). Inertia from these valvetrain parts makes OHV engines more susceptible to
361:
Although OHV engines have simpler drive systems for the camshaft, there are a greater number of moving parts in the
806:
1415:
1329:
1274:
1226:
1134:
249:
1410:
1251:
960:
232:
1185:
93:
185:
in the United States built a motorised tricycle powered by a single-cylinder OHV engine. Marr was hired by
1007:
328:
1124:
261:
257:
245:
260:
to reduce fuel consumption and exhaust emissions. In 2008, the first production pushrod engine to use
1119:
891:
648:
640:
697:
1269:
1167:
897:
499:
182:
1190:
987:
62:
992:
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151:
77:
1284:
1241:
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256:
In the early 21st century, several pushrod V8 engines from
General Motors and Chrysler used
202:
111:
122:
1395:
1106:
955:
912:
220:
209:
89:
66:
103:
engines used a hybrid design combining elements of both side-valves and overhead valves.
1261:
1231:
1086:
853:
727:
636:
571:"The Buick, A Complete History," third ed., 1987, Terry P. Dunham and Lawrence Gustin.
1448:
1433:
1324:
1317:
1294:
1139:
1071:
1066:
1030:
947:
887:
848:
838:
198:
158:
135:
The first internal combustion engines were based on steam engines and therefore used
116:
58:
54:
1050:
1045:
1012:
917:
907:
843:
827:
332:
295:
144:
70:
96:
are good examples), so they can essentially be considered overhead valve designs.
1428:
1312:
1129:
1081:
1040:
997:
927:
366:
265:
208:
Several other manufacturers began to produce OHV engines, such as the 1906–1912
140:
136:
694:"Automotive Engineering International Online: Powertrain Technology Newsletter"
1400:
1360:
1339:
1334:
1236:
1221:
1144:
1076:
1002:
942:
873:
754:
402:
362:
170:
100:
85:
35:
17:
775:
608:
1355:
1096:
1091:
878:
858:
336:
280:
276:
216:
283:(with intake manifold removed), showing the camshaft, pushrods, and rockers
1378:
1374:
1246:
977:
902:
868:
354:
Compared with OHC engines, OHV engines have the following disadvantages:
347:
324:
320:
162:
1405:
1289:
166:
81:
1216:
1195:
972:
922:
237:
The first overhead camshaft (OHC) engine dates back to 1902, in the
69:, where the valves were located below the combustion chamber in the
30:
315:
OHV engines have a less complex drive system for the camshaft than
680:
623:"What Was the Final Year for a New Flathead-Powered American Car?"
275:
248:
motor race, Team Penske entered a car powered by the custom-built
186:
121:
110:
29:
755:"What is the difference between OHV, OHC, SOHC and DOHC engines?"
309:
family is a popular example of these kinds of OHV V-type engines.
1370:
666:
779:
287:
OHV engines have several advantages compared with OHC engines:
817:
316:
219:
joined Buick in almost exclusive use of OHV engines. However,
302:
Using the same cylinder head casting for both cylinder banks:
335:, or multiple chains. These systems require the use of
478:. Berlin: Springer Berlin Heidelberg. pp. 5, 62.
645:
376:
allowing for higher rates of combustion and exhaust.
1388:
1348:
1303:
1260:
1209:
1176:
1158:
1105:
1059:
1021:
941:
826:
647:(Third ed.). New York: E. P. Dutton. p.
392:
390:
716:
714:
791:
8:
373:Constraints on valve quantity and location:
126:1904 patent for Buick overhead valve engine
798:
784:
776:
307:General Motors LS-based small-block engine
161:used overhead poppet valves actuated by a
723:"The Pushrod Engine Finally Gets its Due"
399:"HowStuffWorks "Camshaft Configurations""
864:Crankcase ventilation system (PCV valve)
559:Walter L. Marr, Buick's Amazing Engineer
401:. Auto.howstuffworks.com. Archived from
386:
34:Components of a traditional OHV engine
27:Type of piston engine valvetrain design
1455:Cam-in-block valvetrain configurations
561:. Boston: Racemaker Press. p. 14.
84:(hence the term "pushrod engine") and
7:
319:engines. Most OHC engines drive the
735:from the original on 26 August 2014
683:even use OHC motors for lawnmowers!
139:. This was the case for the first
25:
67:flathead (or "sidevalve") engines
1460:Engine valvetrain configurations
453:. Berlin: Springer. p. 17.
191:Buick Auto-Vim and Power Company
57:whose valves are located in the
966:Overhead valve (pushrod) layout
609:"Chevrolet 1930s General Specs"
506:from the original on 2017-08-28
451:Die Entstehung des Dieselmotors
266:Dodge Viper (fourth generation)
313:Simpler camshaft drive system:
181:In 1898, bicycle manufacturer
115:1894 prototype overhead valve
1:
643:. In Georgano, G. N. (ed.).
369:at high engine speeds (RPM).
147:became increasingly common.
721:Webster, Larry (May 2004).
679:Now, manufacturers such as
343:Simpler lubrication system:
1486:
807:Internal combustion engine
397:Nice, Karim (2000-12-13).
292:Smaller overall packaging:
230:
213:Vertical 4-Cylinder Engine
1424:
1275:Diesel particulate filter
1227:Idle air control actuator
1168:Engine control unit (ECU)
813:
696:. Sae.org. Archived from
227:Overhead camshaft engines
49:) and sometimes called a
1340:Viscous fan (fan clutch)
1252:Throttle position sensor
961:Overhead camshaft layout
557:; Cox, James H. (2007).
233:Overhead camshaft engine
150:Beginning with the 1885
879:Core plug (freeze plug)
474:Diesel, Rudolf (1893).
449:Diesel, Rudolf (1913).
159:prototype Diesel engine
359:Limited engine speeds:
284:
264:was introduced in the
177:Production OHV engines
127:
119:
65:. This contrasts with
38:
279:
262:variable valve timing
258:cylinder deactivation
246:1994 Indianapolis 500
125:
114:
43:overhead valve engine
33:
1120:Compression ignition
500:"U.S. patent 563140"
1470:Scottish inventions
1270:Catalytic converter
625:. 20 December 2018.
424:"Part I: V-engines"
201:. The engine was a
183:Walter Lorenzo Marr
101:intake-over-exhaust
1465:Motorcycle engines
1396:Knocking / pinging
988:Combustion chamber
597:on April 28, 2016.
555:Kimes, Beverly Rae
285:
250:Mercedes-Benz 500I
128:
120:
63:combustion chamber
39:
1442:
1441:
1411:Stratified charge
1178:Electrical system
1160:Engine management
993:Compression ratio
933:Starter ring gear
832:rotating assembly
535:on 28 August 2017
485:978-3-642-64949-3
460:978-3-642-64940-0
152:Daimler Reitwagen
78:overhead camshaft
16:(Redirected from
1477:
1285:Exhaust manifold
1150:Spark plug wires
1036:Boost controller
1023:Forced induction
800:
793:
786:
777:
770:
769:
767:
765:
759:www.samarins.com
751:
745:
744:
742:
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690:
684:
677:
671:
670:
633:
627:
626:
619:
613:
612:
605:
599:
598:
593:. Archived from
591:"Wright Engines"
587:
581:
578:
572:
569:
563:
562:
551:
545:
544:
542:
540:
531:. Archived from
529:pdfpiw.uspto.gov
521:
515:
514:
512:
511:
496:
490:
489:
471:
465:
464:
446:
440:
439:
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428:www.topspeed.com
420:
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21:
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1420:
1416:Top dead centre
1384:
1344:
1299:
1256:
1205:
1179:
1172:
1161:
1154:
1101:
1055:
1017:
973:Tappet / lifter
956:Flathead layout
946:
937:
831:
822:
809:
804:
774:
773:
763:
761:
753:
752:
748:
738:
736:
720:
719:
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703:
701:
692:
691:
687:
678:
674:
659:
637:Georgano, G. N.
635:
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630:
621:
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607:
606:
602:
589:
588:
584:
579:
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566:
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548:
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525:"Patent Images"
523:
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417:
408:
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274:
235:
229:
210:Wright Brothers
179:
133:
109:
45:, abbreviated (
28:
23:
22:
15:
12:
11:
5:
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1473:
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1321:
1320:
1315:
1309:
1307:
1305:Cooling system
1301:
1300:
1298:
1297:
1292:
1287:
1282:
1277:
1272:
1266:
1264:
1262:Exhaust system
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1257:
1255:
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1244:
1239:
1234:
1232:Inlet manifold
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1103:
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1099:
1094:
1089:
1087:Fuel injection
1084:
1079:
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1063:
1061:
1057:
1056:
1054:
1053:
1048:
1043:
1038:
1033:
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1005:
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939:
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920:
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910:
905:
900:
895:
881:
876:
871:
866:
861:
856:
854:Connecting rod
851:
846:
841:
835:
833:
824:
823:
814:
811:
810:
805:
803:
802:
795:
788:
780:
772:
771:
746:
728:Car and Driver
710:
685:
672:
657:
628:
614:
600:
582:
573:
564:
546:
516:
491:
484:
466:
459:
441:
430:. 29 July 2006
415:
385:
384:
382:
379:
378:
377:
370:
352:
351:
340:
310:
299:
273:
270:
231:Main article:
228:
225:
178:
175:
132:
129:
108:
105:
51:pushrod engine
26:
24:
18:Pushrod engine
14:
13:
10:
9:
6:
4:
3:
2:
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1471:
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1326:
1323:
1322:
1319:
1318:Water cooling
1316:
1314:
1311:
1310:
1308:
1306:
1302:
1296:
1295:Oxygen sensor
1293:
1291:
1288:
1286:
1283:
1281:
1278:
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1273:
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1268:
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1228:
1225:
1223:
1220:
1218:
1215:
1214:
1212:
1210:Intake system
1208:
1202:
1201:Starter motor
1199:
1197:
1194:
1192:
1189:
1187:
1184:
1183:
1181:
1175:
1169:
1166:
1165:
1163:
1157:
1151:
1148:
1146:
1143:
1141:
1140:Ignition coil
1138:
1136:
1133:
1131:
1128:
1126:
1123:
1121:
1118:
1116:
1113:
1112:
1110:
1108:
1104:
1098:
1095:
1093:
1090:
1088:
1085:
1083:
1080:
1078:
1075:
1073:
1072:Petrol engine
1070:
1068:
1067:Diesel engine
1065:
1064:
1062:
1058:
1052:
1049:
1047:
1044:
1042:
1039:
1037:
1034:
1032:
1031:Blowoff valve
1029:
1028:
1026:
1024:
1020:
1014:
1011:
1009:
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979:
976:
974:
971:
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967:
964:
962:
959:
957:
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953:
951:
949:
948:Cylinder head
944:
940:
934:
931:
929:
926:
924:
921:
919:
916:
914:
911:
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906:
904:
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870:
867:
865:
862:
860:
857:
855:
852:
850:
847:
845:
842:
840:
839:Balance shaft
837:
836:
834:
829:
825:
821:
819:
812:
808:
801:
796:
794:
789:
787:
782:
781:
778:
760:
756:
750:
747:
734:
730:
729:
724:
717:
715:
711:
700:on 2011-08-05
699:
695:
689:
686:
682:
676:
673:
668:
664:
660:
658:0-525-93254-2
654:
650:
646:
642:
638:
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629:
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583:
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492:
487:
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462:
456:
452:
445:
442:
429:
425:
419:
416:
405:on 2016-02-02
404:
400:
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349:
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251:
247:
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226:
224:
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218:
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211:
206:
204:
200:
199:Buick Model B
196:
195:Marr Auto-Car
192:
188:
184:
176:
174:
172:
168:
164:
160:
155:
153:
148:
146:
145:poppet valves
142:
138:
130:
124:
118:
117:Diesel engine
113:
106:
104:
102:
97:
95:
91:
87:
83:
79:
74:
72:
68:
64:
60:
59:cylinder head
56:
55:piston engine
52:
48:
44:
37:
32:
19:
1325:Electric fan
1125:Coil-on-plug
1051:Turbocharger
1046:Supercharger
965:
918:Main bearing
908:Firing order
898:Displacement
844:Block heater
828:Engine block
816:Part of the
815:
762:. Retrieved
758:
749:
737:. Retrieved
726:
702:. Retrieved
698:the original
688:
675:
644:
631:
617:
603:
595:the original
585:
576:
567:
558:
549:
537:. Retrieved
533:the original
528:
519:
508:. Retrieved
494:
475:
469:
450:
444:
432:. Retrieved
427:
418:
407:. Retrieved
403:the original
372:
358:
353:
342:
312:
301:
296:cam-in-block
291:
286:
255:
243:
236:
212:
207:
190:
189:(then named
180:
156:
149:
137:slide valves
134:
131:Predecessors
98:
76:Although an
75:
71:engine block
50:
46:
42:
40:
1349:Lubrication
1313:Air cooling
1130:Distributor
1082:Fuel filter
1060:Fuel system
1041:Intercooler
1008:Timing belt
998:Head gasket
928:Piston ring
764:19 December
739:31 December
434:13 December
367:valve float
329:timing belt
215:. In 1911,
171:rocker arms
141:Otto engine
99:Some early
86:rocker arms
1449:Categories
1401:Power band
1361:Oil filter
1335:Thermostat
1280:EGT sensor
1242:MAF sensor
1237:MAP sensor
1222:Air filter
1186:Alternator
1145:Spark plug
1077:Carburetor
1003:Rocker arm
943:Valvetrain
874:Crankshaft
818:Automobile
704:2011-09-07
641:"Maudslay"
510:2017-06-07
409:2011-09-07
381:References
363:valvetrain
337:tensioners
61:above the
36:valvetrain
1135:Glow plug
1097:Fuel tank
1092:Fuel pump
859:Crankcase
639:(1982) .
325:camshafts
281:V8 engine
217:Chevrolet
203:flat-twin
157:The 1894
1434:Category
1379:Dry sump
1375:Wet sump
1366:Oil pump
1330:Radiator
1247:Throttle
1107:Ignition
978:Camshaft
903:Flywheel
884:Cylinder
869:Crankpin
733:Archived
667:81-71857
504:Archived
348:trunnion
327:using a
321:camshaft
221:flathead
167:pushrods
163:camshaft
94:Opel CIH
90:Ford CVH
82:pushrods
1406:Redline
1290:Muffler
1191:Battery
1115:Magneto
244:At the
107:History
53:, is a
1429:Portal
1217:Airbox
1196:Dynamo
923:Piston
913:Stroke
892:layout
820:series
665:
655:
482:
457:
272:Design
1389:Other
1013:Valve
983:Chest
681:Honda
539:8 May
346:end,
333:chain
187:Buick
1371:Sump
888:bank
849:Bore
766:2019
741:2014
663:LCCN
653:ISBN
541:2018
480:ISBN
455:ISBN
436:2019
331:, a
294:The
239:Marr
169:and
92:and
1356:Oil
945:and
830:and
649:407
323:or
317:OHC
73:.
47:OHV
41:An
1451::
1377:,
890:,
757:.
731:.
725:.
713:^
661:.
651:.
527:.
502:.
426:.
389:^
268:.
165:,
1381:)
1373:(
894:)
886:(
799:e
792:t
785:v
768:.
743:.
707:.
669:.
611:.
543:.
513:.
488:.
463:.
438:.
412:.
20:)
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